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Sample records for ti shih chieh

  1. Cloning and characterization of WRKY gene homologs in Chieh-qua (Benincasa hispida Cogn. var. Chieh-qua How) and their expression in response to fusaric acid treatment.

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    Mao, Yizhou; Jiang, Biao; Peng, Qingwu; Liu, Wenrui; Lin, Yue; Xie, Dasen; He, Xiaoming; Li, Shaoshan

    2017-05-01

    The WRKY transcription factors play an important role in plant resistance for biotic and abiotic stresses. In the present study, we cloned 10 WRKY gene homologs (CqWRKY) in Chieh-qua (Benincasa hispida Cogn. var. Chieh-qua) using the rapid-amplification of cDNA ends (RACE) or homology-based cloning methods. We characterized the structure of these CqWRKY genes. Phylogenetic analysis of these sequences with cucumber homologs suggested possible structural conservation of these genes among cucurbit crops. We examined the expression levels of these genes in response to fusaric acid (FA) treatment between resistant and susceptible Chieh-qua lines with quantitative real-time PCR. All genes could be upregulated upon FA treatment, but four CqWRKY genes exhibited differential expression between resistant and susceptible lines before and after FA application. CqWRKY31 seemed to be a positive regulator while CqWRKY1, CqWRKY23 and CqWRKY53 were negative regulators of fusaric resistance. This is the first report of characterization of WRKY family genes in Chieh-qua. The results may also be useful in breeding Chieh-qua for Fusarium wilt resistance.

  2. Residue behavior and risk assessment of mixed formulation of imidacloprid and chlorfenapyr in chieh-qua under field conditions.

    Science.gov (United States)

    Huang, Jian Xiang; Liu, Cong Yun; Lu, Da Hai; Chen, Jia Jia; Deng, Yi Cai; Wang, Fu Hua

    2015-10-01

    A simple and rapid method based on high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was developed for the simultaneous determination of imidacloprid and chlorfenapyr residues in chieh-qua. Field trials were designed to investigate the dissipation and terminal residue behavior of the mixed formulation of imidacloprid and chlorfenapyr in chieh-qua in Guangzhou and Nanning areas. Risk assessment was performed by calculating the risk quotient (RQ) values. The developed analytical method exhibited recoveries of 89.9-110.3% with relative standard deviations (RSDs) of 2.8-12.5% at the spiked levels of 0.01, 0.10, and 1.00 mg/kg. The limit of detection (LOD) was 0.003 mg/kg, and the limit of quantification (LOQ) was 0.01 mg/kg for both imidacloprid and chlorfenapyr. It was found that the half-lives of imidacloprid in chieh-qua under field conditions were 3.3 and 3.5 days in Guangzhou and Nanning at a dose of 180 g ai/ha, while the half-lives of chlorfenapyr were 3.3 and 2.6 days, respectively. The terminal residues of imidacloprid and chlorfenapyr were from 0.01 to 0.21 mg/kg and from 0.01 to 0.46 mg/kg, respectively. Results of dietary exposure assessment showed that the RQ values were much lower than 1, indicating that the risk of imidacloprid and chlorfenapyr applied in chieh-qua was negligible to human health under recommended dosage and good agricultural practices. The proposed study would provide guidance for safe and reasonable use of imidacloprid and chlorfenapyr in chieh-qua cultivation in China.

  3. Use of Shih in Chinese Operational Art

    Science.gov (United States)

    2016-05-26

    These include leaders seeking to manipulate context, build troop morale through context, use an indirect approach, and exploit propensity within a...characteristics help determine whether or not shih was a factor in a given conflict. These include leaders seeking to manipulate context, build troop morale ...U.S. Army War College, 2011), ix-x; William H. Mott and Jae Chang Kim, The Philosophy of Chinese Military Culture: Shih vs. Li (New York, NY: Palgrave

  4. Journal of Biosciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Author Affiliations. Chi-Fang Chin1 Arthur Chun-Chieh Shih2 Kuo-Chin Fan1 3. Department of Computer Science and Information Engineering, National Central University, Chung-Li, Taiwan; Institute of Information Science, Academia Sinica, Taipei, Taiwan; Department of Informatics, Fo Guang Univeristy, Ilan, Taiwan ...

  5. East Asia: Southeast Asia

    Science.gov (United States)

    1990-09-05

    supporting role in the founding of Malaysia. Some people describe their role as having a position but having no authority. During the cogon grass campaign...Pian Hon Yun Shih-chin’s luck was much greater than Kuo Wei- chieh’s. Although both are deputy ministers, their grass - roots power is weak. Kuo

  6. A case of gastrinoma in a Shih-Tzu dog.

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    Fukushima, Ushio; Sato, Miyuki; Okano, Shozo; Aramaki, Yoshitaka; Ito, Hiroshi; Yoshioka, Kazuki; Oyamada, Toshifumi; Uechi, Masami

    2004-03-01

    A five-year-old male Shih-Tzu dog presented with severe vomiting and weight loss. The clinical signs were successfully improved by an eight-day treatment with an H(2)-receptor antagonist, gastrointestinal protectant and antibiotics. Ten days later, however, recurrence of vomiting was seen despite continuous medical treatment. Based on clinical signs and the results of various diagnostic tests including CBC, biochemical analysis, contrast radiography, and endoscopy, a duodenal or pancreatic neoplasm was suspected and exploratory laparotomy was conducted. Some swollen pancreatic regions were found, and biopsy of the pancreas indicated the diagnosis of a gastrin-secreting tumor. Consequently, based on a high serum gastrin level as well as clinical signs and immunohistological findings, we diagnosed the disease as canine gastrinoma, a rare tumor of the pancreas.

  7. Double Intussusception in a Shih-Tzu Puppy: The Triple-Circle Sign

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    J. M. Kim, S. S. Kang1, G. Kim and S. H. Choi*

    2012-05-01

    Full Text Available Intussusception is a common surgical disorder in puppies. Double intussusception (DI however, is an extremely rare form of this pathology. The authors report a case of a 3-month-old, Shih-Tzu puppy referred to Veterinary Medical Center of Chungbuk National University, Korea with symptoms of abdominal discomfort, intermittent vomiting and bloody diarrhea for 5 days. Ultrasonographic examination of the left mid-abdominal region revealed a mass with a ‘triple case’ sign completely different from the classic ‘target sign’. The surgical intervention confirmed it to be an ileocecal DI in ascending colon. The case emphasizes the rare ‘triple case’ sign as a descriptive finding on ultrasonography in DI presentations.

  8. Calming effect of orally administered γ-aminobutyric acid in Shih Tzu dogs.

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    Uetake, Katsuji; Okumoto, Ayano; Tani, Noriko; Goto, Akihiro; Tanaka, Toshio

    2012-12-01

    The calming effects of γ-aminobutyric acid (GABA) by oral administration were investigated in four adult Shih Tzu dogs. Three dosage levels (1, 2 and 4 mg/kg body weight) and non-administration were tested by an increase and decrease method. Changes in activity (for 1.5 h) and urinary cortisol levels (pre-administration, 3 and 7 h later) of dogs were monitored after administration. Without reference to dosage level, the mean times spent standing (P = 0.06), sitting (P level was observed at 7 h after administration (P GABA exerts calming effects on dogs as well as humans. © 2012 The Authors. Animal Science Journal © 2012 Japanese Society of Animal Science.

  9. Factors Associated with Fear of Falling among Community-Dwelling Older Adults in the Shih-Pai Study in Taiwan

    OpenAIRE

    Chang, Hsiao-Ting; Chen, Hsi-Chung; Chou, Pesus

    2016-01-01

    Background Fear of falling is an important risk indicator for adverse health related outcomes in older adults. However, factors associated with fear of falling among community-dwelling older adults are not well-explored. Objectives To explore the quality of life and associated factors in fear of falling among older people in the Shih-Pai area in Taiwan. Methods This community-based survey recruited three thousand eight hundred and twenty-four older adults aged ? 65 years. The measurements inc...

  10. Information from Yüan Shih on the Military Cooperation between the Golden Horde and the Yüan Dynasty.

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    Zhu-Cheng Zhao.

    2016-12-01

    Full Text Available Research objective: to reveal relations in military affairs between the Golden Horde and the Yüan Dynasty on the basis of the data of the Chinese dynastic history Yüan shih. Research materials: because of the large distance between these medieval Chinggisid powers, internecine strife between the houses of the Jochids and Toluids, armed conflicts between Arik-Boke and Kublai and due to the fact that the rulers of the Jochid ulus supported Arik-Boke, their state became independent from the Great Mongol Empire. Later on, long-term military conflicts and political turmoil interrupted communication between Sarai and Khanbalik. The Jochid ulus and the Yuan dynasty conducted their own foreign policies. However, communication between them was not interrupted and some information from the Golden Horde still fall in Chinese chronicles. One of the important and fundamental sources relating to the Mongol history is Yüan shih (History of the Yüan Dynasty. This written source contains some materials (although in fragments revealing the nature of the relations between the Yuan Dynasty and the Golden Horde. Research results and novelty: the author has provided information that the military units composed of the peoples of the Golden Horde (primarily of the Ases and Kipchaks, as well as of the Russians were among the troops in the Yüan Empire. At the same time, their proportion was significant both in the composition of commanding staff, as well as among ordinary soldiers. However, the source does not contain any information about the conditions under which these warriors arrived in China as well as about the routes they were moving. It is indisputable fact that they were sent to the Far East from the Jochid ulus during the highest power of this state in the reign of khan Uzbek. Perhaps it was an indication that the Yüan emperor displayed his authority over Sarai Khan in the political sense as well.

  11. Innovate the Teaching of Taiwaness History: An Application of Multimedia Distance Learning—A Web-site Construction Sample of Shih Hsin University

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    Shaw-Fong Lee

    2004-03-01

    Full Text Available Traditionally, the teaching of history course mostly utilizes face to face instruction and oral presentation. Along with the development of educational technology, the teaching methods could be more various such as using internet and multimedia. Literature reviews also indicate that using internet and multimedia may improve the effect of learning and teaching. This paper explores the development of a web-based instructional system for the course of Taiwanese History at Shih Hsin University.The result and the product of this development project is the web site, http://distance.shu.edu.tw/taiwan/list.htm. The content of the web-site includes instructional materials such as animations, videos, pictures, texts, historical maps, and so on. The developmental methods used in this project use curriculum design, survey, interview, review of literatures and focus group discussion.[Article content in Chinese

  12. A Case Study of Synchronous Distance Learning Between Shih Chien University and Beijing Foreign Studies University

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    Yen-Fen Lo

    2016-08-01

    Full Text Available Shih Chien University and Beijing Foreign Studies University collaboratively launched a project to offer synchronous distance learning courses on "Case Studies of Taiwanese Entrepreneurs" since February 2012. The three objectives of this study are: (1 to explore the Cross-Strait students' motives for selecting the course; (2 to examine the students' accommodation condition before and after completing the course; (3 to discuss the student's level of satisfaction of the course. This study uses qualitative data from case study interviews conducted in the second year of the project based on the research focus of the Cross-Strait students' motivation and satisfaction of the course. The research analysis tools are content analysis and theory triangulation. The findings are: (1 Cross-Strait students are motivated by their curiosity about the course, interest in the contents, and willingness to experience the novelty of distance learning to select the course; (2 the results of Cross-Strait students' accommodation condition are correlated to their interactions with the professor, the familiarity with the materials, the quality of the communication equipment, and the clarity of the images; (3 Cross-Strait students all accept the method of synchronous distance learning; (4 the quality of communication equipment has the lowest level of satisfaction.

  13. Correlates of self-report chronic insomnia disorders with 1-6 month and 6-month durations in home-dwelling urban older adults - the Shih-Pai Sleep Study in Taiwan: a cross-sectional community study.

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    Chiou, Jing-Hui; Chen, Hsi-Chung; Chen, Kuang-Hung; Chou, Pesus

    2016-06-03

    To examine the correlates of insomnia disorder with different durations in home-dwelling older adults. A cross-sectional survey in the Shih-Pai area of Taipei City, Taiwan (The Shih-Pai Sleep Study). A total 4047 subjects over the age of 65 years completed the study (2259 men and 1788 women). The Pittsburgh Sleep Quality Index and the duration of insomnia symptoms were used to identify DSM-IV 1-6 month and 6-month insomnia disorders. The prevalence of DSM-IV defined insomnia disorder was 5.8 %; two-thirds of these case lasted for ≥6 months. The shared correlates for both 1-6 and 6-month insomnia disorders were gender (women), depression and moderate pain. Pulmonary diseases were exclusively associated with 1-6 month insomnia disorder (OR: 2.57, 95 % CI: 1.46-4.52). In contrast, heart disease (OR: 1.73, 95 % CI: 1.21-2.49) and severe pain (OR: 2.34, 95 % CI: 1.14-4.40) were associated with 6-month insomnia disorder. The prevalence of persistent insomnia disorder is higher than short-term insomnia disorder. Correlates for less persistent and more persistent insomnia disorder appears to be partially different. Duration quantifiers may be important in the identification of the etiology of insomnia and further studies with follow-ups are needed to examine the order of developing insomnia disorder and associated conditions.

  14. PIIID-formed (Ti, O)/Ti, (Ti, N)/Ti and (Ti, O, N)/Ti coatings on NiTi shape memory alloy for medical applications

    Energy Technology Data Exchange (ETDEWEB)

    Sun Tao, E-mail: taosun@hotmail.com.hk [Department of Mechanical Engineering, University of Hong Kong, Pokfulam Road (Hong Kong); Institute of Microelectronics, Agency for Science, Technology and Research (A-STAR) (Singapore); Wang Langping, E-mail: aplpwang@hit.edu.cn [State Key Lab of Advanced Welding and Joining, Harbin Institute of Technology (China); Wang Min; Tong Howang [Department of Mechanical Engineering, University of Hong Kong, Pokfulam Road (Hong Kong); Lu, William W. [Department of Orthopedics and Traumatology, University of Hong Kong, Sassoon Road (Hong Kong)

    2012-08-01

    (Ti, O)/Ti, (Ti, N)/Ti and (Ti, O, N)/Ti composite coatings were fabricated on NiTi shape memory alloy via plasma immersion ion implantation and deposition (PIIID). Surface morphology of samples was investigated using atomic force microscopy (AFM) and scanning electron microscopy (SEM). Cross-sectional morphology indicated that the PIIID-formed coatings were dense and uniform. X-ray diffraction (XRD) was used to characterize the phase composition of samples. X-ray photoelectron spectroscopy (XPS) results showed that the surface of coated NiTi SMA samples was Ni-free. Nanoindentation measurements and pin-on-disc tests were carried out to evaluate mechanical properties and wear resistance of coated NiTi SMA, respectively. For the in vitro biological assessment of the composite coatings in terms of cell morphology and cell viability, osteoblast-like SaOS-2 cells and breast cancer MCF-7 cells were cultured on NiTi SMA samples, respectively. SaOS-2 cells attached and spread better on coated NiTi SMA. Viability of MCF-7 cells showed that the PIIID-formed composite coatings were noncytotoxic and coated samples were more biocompatible than uncoated samples. - Highlights: Black-Right-Pointing-Pointer PIIID-formed coatings were fabricated on NiTi SMA to improve its biocompatibility. Black-Right-Pointing-Pointer Microstructure, mechanical properties and biocompatibility of coatings were investigated. Black-Right-Pointing-Pointer All PIIID-formed composite coatings were noncytotoxic and cytocompatible.

  15. Factors Associated with Fear of Falling among Community-Dwelling Older Adults in the Shih-Pai Study in Taiwan.

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    Hsiao-Ting Chang

    Full Text Available Fear of falling is an important risk indicator for adverse health related outcomes in older adults. However, factors associated with fear of falling among community-dwelling older adults are not well-explored.To explore the quality of life and associated factors in fear of falling among older people in the Shih-Pai area in Taiwan.This community-based survey recruited three thousand eight hundred and twenty-four older adults aged ≥ 65 years. The measurements included a structured questionnaire, including quality of life by using Short-Form 36, and information of fear of falling, fall history, demographics, medical conditions, insomnia, sleep quality, depression and subjective health through face-to-face interviews.A total of 53.4% of participants reported a fear of falling. The rate of fear of falling was higher in female subjects. Subjects with fear of falling had lower Short Form-36 scores both for men and women. Falls in the previous year, older age, insomnia, depression and worse subjective health were correlates of fear of falling for both sexes. Male-specific associations with fear of falling were the accessibility of medical help in an emergency, diabetes mellitus and stroke. In parallel, cardiovascular diseases were a female-specific correlate for fear of falling.Fear of falling is prevalent among community-dwelling older adults. It is seems that there are gender differences in fear of falling with respect to the prevalence and associated factors in older adults. Gender differences should be considered when planning prevention and intervention strategies for fear of falling among older people.

  16. Gender Difference in the Interaction Effects of Diabetes and Hypertension on Stroke among the Elderly in the Shih-Pai Study, Taiwan.

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    Yun-Ju Lai

    Full Text Available To investigate the interaction effects of diabetes and hypertension on stroke, and also investigate the independent and interaction effects of parental history and environmental factors on diabetes and hypertension in a cross-sectional elderly population.The Shih-Pai Community Medical Service Program was a community-based, fixed cohort study conducted between June 1999 and November 2002. Socio-demographic and clinical data of subjects aged 65 years and older were collected by well-trained interviewers during home visits. Interaction effects were analyzed using Rothman's synergy index (SI.In total, 4,124 subjects were included in the study, with 2,284 males and 1,840 females. The synergistic interaction of diabetes and hypertension on stroke was statistically significant in women (SI = 3.16, 95% CI: 1.35-7.39. The synergistic interaction of parental diabetes and being overweight on diabetes was only statistically significant in men, and not in women (SI = 3.30, 95% CI: 1.00-10.83 in men, and SI = 1.15, 95% CI: 0.30-4.39 in women.A synergistic interaction was found for diabetes and hypertension in both sexes when parental history and being overweight were combined. Furthermore, combining diabetes and hypertension in elderly women was significant in terms of the risk of stroke. Strategies to control risk factors in individuals at additional high risk are urgently needed.

  17. Nanomechanical properties of TiCN and TiCN/Ti coatings on Ti prepared by Filtered Arc Deposition

    International Nuclear Information System (INIS)

    Sun, Yong; Lu, Cheng; Yu, Hailiang; Kiet Tieu, A.; Su, Lihong; Zhao, Yue; Zhu, Hongtao; Kong, Charlie

    2015-01-01

    Monolayer TiCN and multilayer TiCN/Ti coatings were deposited on the surface of Ti using the Filtered Arc Deposition System (FADS). Nanoindentation tests were performed on both coatings. The multilayer TiCN/Ti coating exhibited better ductility than the monolayer TiCN coating. The lattice constants of the coatings were characterized by X-ray diffraction. Transmission Electron Microscopy (TEM) was used to investigate the fracture behavior of the coatings. Inter-columnar, inclined and lateral cracks were found to be the dominant crack modes in the monolayer TiCN coatings while small bending crack and radial crack were the dominant crack modes in the multilayer TiCN/Ti coatings. The Finite Element Method (FEM) was used to simulate the indentation process. It was found that the Ti interlayer in the multilayer TiCN/Ti coating could efficiently suppress the fracture, which is responsible for the improved ductility of the multilayer TiCN/Ti coating

  18. Comparison of mechanical behavior of TiN, TiNC, CrN/TiNC, TiN/TiNC films on 9Cr18 steel by PVD

    Science.gov (United States)

    Feng, Xingguo; Zhang, Yanshuai; Hu, Hanjun; Zheng, Yugang; Zhang, Kaifeng; Zhou, Hui

    2017-11-01

    TiN, TiNC, CrN/TiNC and TiN/TiNC films were deposited on 9Cr18 steel using magnetron sputtering technique. The morphology, composition, chemical state and crystalline structure of the films were observed and analyzed by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and scanning electron microscopy (SEM). Hardness and adhesion force were tested by nanoindentation and scratch tester, respectively. The friction and wear behavior of TiN, TiNC, CrN/TiNC and TiN/TiNC films sliding against GCr15 balls were investigated and compared synthetically using ball-on-disk tribometer. It was found that Tisbnd N, Tisbnd C, Tisbnd Nsbnd C and Csbnd C bonds were formed. The TiN/TiNC film was composed of TiN, TiC and TiNC phases. Hardness and adhesion force results indicated that although the TiN film possessed the highest hardness, its adhesion force was lowest among all the films. Tribological test results showed that the friction coefficient of TiN/TiNC was much lower than that of TiN and the wear rate decreases remarkably from 2.3 × 10-15 m3/Nm to 7.1 × 10-16 m3/Nm, which indicated the TiN/TiNC film has better wear resistance.

  19. Microstructure and corrosion resistance of TC2 Ti alloy by laser cladding with Ti/TiC/TiB_2 powders

    International Nuclear Information System (INIS)

    Diao, Yunhua; Zhang, Kemin

    2015-01-01

    Highlights: • A TiC/TiB_2 composite coating was produced onto a TC2 Ti alloy by laser cladding with Ti/TiC/TiB_2 powders. • A maximum hardness of 1100 HV was achieved in the laser clad TiC/TiB_2 composite layer. • Corrosion resistance of the TC2 alloy in NaCl (3.5 wt%) aqueous solution can be improved after laser cladding. - Abstract: In the present work, a TiC/TiB_2 composite coating was produced onto a TC2 Ti alloy by laser cladding with Ti/TiC/TiB_2 powders. The surface microstructure, phase components and compositions were characterized with methods of optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffractometry (XRD), and energy dispersive spectrometry (EDS). The cladding layer is consisted of Ti, TiC and TiB_2. And the surface microhardness was measured. After laser cladding, a maximum hardness of 1100 HV is achieved in the laser cladding surface layer, which is more three times higher than that of the TC2 substrate (∼300 HV). Due to the formation of TiC and TiB_2 intermetallic compounds in the alloyed region and grain refinement, the microhardness of coating is higher than TC2 Ti alloy. In this paper, the corrosion property of matrix material and treated samples were both measured in NaCl (3.5 wt%) aqueous solution. From the result we can see that the laser cladding specimens’ corrosion property is clearly becoming better than that of the substrate.

  20. Characteristics of laser clad α-Ti/TiC+(Ti,W)C1-x/Ti2SC+TiS composite coatings on TA2 titanium alloy

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    Zhai, Yong-Jie; Liu, Xiu-Bo; Qiao, Shi-Jie; Wang, Ming-Di; Lu, Xiao-Long; Wang, Yong-Guang; Chen, Yao; Ying, Li-Xia

    2017-03-01

    TiC reinforced Ti matrix composite coating with Ti2SC/TiS lubricant phases in-situ synthesized were prepared on TA2 titanium alloy by laser cladding with different powder mixtures: 40%Ti-19.5%TiC-40.5%WS2, 40%Ti-25.2%TiC-34.8%WS2, 40%Ti-29.4%TiC-30.6%WS2 (wt%). The phase compositions, microstructure, microhardness and tribological behaviors and wear mechanisms of coatings were investigated systematically. Results indicate that the main phase compositions of three coatings are all continuous matrix α-Ti, reinforced phases of (Ti,W)C1-x and TiC, lubricant phases of Ti2SC and TiS. The microhardness of the three different coatings are 927.1 HV0.5, 1007.5 HV0.5 and 1052.3 HV0.5, respectively. Compared with the TA2 titanium alloy (approximately 180 HV0.5), the microhardness of coatings have been improved dramatically. The coefficients of friction and the wear rates of those coatings are 0.41 and 30.98×10-5 mm3 N-1 m-1, 0.30 and 18.92×10-5 mm3 N-1 m-1, 0.34 and 15.98×10-5 mm3 N-1 m-1, respectively. Comparatively speaking, the coating fabricated with the powder mixtures of 40%Ti-25.2%TiC-34.8%WS2 presents superior friction reduction and anti-wear properties and the main wear mechanisms of that are slight plastic deformation and adhesive wear.

  1. Formation and growth mechanism of TiC crystal in TiCp/Ti composites

    Institute of Scientific and Technical Information of China (English)

    金云学; 王宏伟; 曾松岩; 张二林

    2002-01-01

    Ti-C and Ti-Al-C alloys were prepared using gravity and directional solidification processes. Morphologies of TiC crystal were investigated by using SEM, XRD and EDX. Also, the formation and growth mechanism of TiC crystal have been analyzed on the basis of coordination polyhedron growth unit theory. During solidification of titanium alloys, the coordination polyhedron growth unit is TiC6. TiC6 growth units stack in a linking mode of edge to edge and form octahedral TiC crystal with {111} planes as present faces. Although the growing geometry of TiC crystal is decided by its lattice structure, the final morphology of TiC crystal depends on the effects of its growth environment. In solute concentration distribution, the super-saturation of C or TiC6 at the corners of octahedral TiC crystal is much higher than that of edges and faces of octahedral TiC crystal. At these corners the driving force for crystal growth is greater and the interface is instable which contribute to quick stacking rate of growth units at these corners and result in secondary dendrite arms along TiC crystallographic 〈100〉 directions. TiC crystal finally grows to be dendrites.

  2. Structural evolution of Ti/TiC multilayers

    International Nuclear Information System (INIS)

    Dahan, I.; Frage, N.; Dariel, M.P.

    2004-01-01

    Hard coatings based on metal/ceramic multilayers with periods in the nanometer range have been shown to possess some potential for improved tribological and mechanical properties. The present work is concerned with the structural evolution of (Ti/TiC) multilayers. Two kinds of multilayers consisting of 30 equithick (40 nm)TiC layers and 20 and 60 nm thick Ti layers, respectively, were sputter deposited on Mo substrates. The structural and the compositional evolution of these multilayers were examined by x-ray diffraction, transition electron microscopy (TEM), high-resolution TEM, Auger electron microscopy spectroscopy and differential thermal analysis (DTA), in the as-deposited state and after various heat treatments up to 500 deg. C. Initially, the Ti layers had a crystalline columnar grain structure displaying a (002) texture. The TiC layers displayed weak crystallinity with a pronounced (111) texture. In the course of the heat treatments, carbon diffused from the carbide layer into the adjacent Ti layers transforming the latter into off-stoichiometric TiC x with x≅0.5 and simultaneously depleting the carbon content of the initial carbide layer. The formed TiC x layers maintained the textural relationship with the neighboring TiC layers, consistent with a transformation that involved only a ABAB to ABC stacking change of the Ti sublattice. Increased mobility of the Ti atoms in carbon-depleted original TiC layers led to their full or partial recrystallization. The thermal effects associated both with the transformation of Ti layers into TiC, due to the influx of carbon atoms, and with the recrystallization of the original TiC layers were clearly revealed by the DTA measurements

  3. Deposition and characterisation of multilayer hard coatings. Ti/TiNδ/TiCxNy/(TiC) a-C:H/(Ti) a-C:H

    International Nuclear Information System (INIS)

    Burinprakhon, T.

    2001-02-01

    Multilayer hard coatings containing Ti, TiNδ, TiC x N y , (TiC m ) a-C:H, (TiC n ) a-C:H, and (Ti) a-C:H were deposited on commercially pure titanium substrates by using an asymmetric bipolar pulsed-dc reactive magnetron sputtering of a titanium target, with Ar, Ar+N 2 , Ar+N 2 +CH 4 , and Ar+CH 4 gas mixtures. The microstructures, elemental compositions and bonding states of the interlayers and the coating surfaces were studied by using cross-sectional transmission electron microscopy (XTEM), electron energy loss spectroscopy (EELS), X-ray diffraction (XRD), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). The microstructure development of the multilayer coating was strongly influenced by target poisoning. As a result of the complete poisoning of the titanium target during the deposition of TiNδ and TiC x N y interlayers, the a-C:H interlayers containing graded titanium and nitrogen contents were found to develop successively to the TiC x N y interlayer without the formation of near-stoichiometric TiC. The (TiC m ) a-C:H interlayer consisted of nano-particles of distorted fcc crystal structure embedded in the a-C:H matrix. The (TiC n ) a-C:H and (Ti) a-C:H top layers were found to be a-C:H matrix without nano-particles. In the (Ti) a-C:H top layer there was no measurable amount of Ti observed, regardless of the variation of CH 4 concentration between 37.5 and 60 % flow rate in Ar+-CH4 gas mixture. The top layer (Ti) a-C:H was found to contain approximately 10 atomic % nitrogen, due to N 2 contamination during deposition caused by low conductance of N 2 through the nominally closed valve of the mass flow controller. The change of the CH 4 concentration during deposition of the top layer (Ti) a-C:H, however, showed a strong influence on the hydrogen content. The comparison of the fluorescence background of the Raman spectra revealed that hydrogen-less (Ti) a-C:H was deposited at a CH 4 concentration of less than 50 % flow rate in Ar. The hardness

  4. Fabrication and characterization of laminated Ti-(TiB+La2O3/Ti composite

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    Yuanfei Han

    2015-10-01

    Full Text Available The incorporation of ceramic particulate reinforcements into titanium alloys can improve the specific strength and specific stiffness, while inevitably reduce the plasticity and ductility. In this study, in situ synthesized multilayer Ti-(TiB+La2O3/Ti composite was designed by learning from the microstructure of nature biological materials with excellent mechanical properties. The Ti-(TiB+La2O3/Ti composite with unique characteristic of laminated structure was prepared by combined powder metallurgy and hot rolling. The method has the synthesize advantages with in-situ reaction of Ti and LaB6 at high temperature and controllability of reinforcements size and constituent phases in composites. The result shows that the pores in the as sintered laminated structure composite completely disappeared after hot rolling at 1050 °C. The agglomerated reinforcement particles were well dispersed and distributed uniformly along the rolling direction. The thickness of pure Ti layer and (TiB+La2O3/Ti composite layer decreased from 1 mm to about 200 μm. Meanwhile, the grains size was refined obviously after rolling deformation. The room temperature tensile test indicates that the elongation of the laminated Ti-(TiB+La2O3/Ti composite improved from 13% to 17% in comparison with the uniform (TiB+La2O3/Ti composite, while the tensile strength had little change. It provides theoretical and experimental basis for fabricating the novel high performance laminated Ti-(TiB+La2O3/Ti composites.

  5. In situ NiTi/Nb(Ti) composite

    International Nuclear Information System (INIS)

    Jiang, Daqiang; Cui, Lishan; Jiang, Jiang; Zheng, Yanjun

    2013-01-01

    Graphical abstract: - Highlights: • In situ NiTi/Nb(Ti) composites were fabricated. • The transformation temperature was affected by the mixing Ti:Ni atomic ratios. • The NiTi component became micron-scale lamella after forging and rolling. • The composite exhibited high strength and high damping capacity. - Abstract: This paper reports on the creation of a series of in situ NiTi/Nb(Ti) composites with controllable transformation temperatures based on the pseudo-binary hypereutectic transformation of NiTi–Nb system. The composite constituent morphology was controlled by forging and rolling. It is found that the thickness of the NiTi lamella in the composite reached micron level after the hot-forging and cold-rolling. The NiTi/Nb(Ti) composite exhibited high damping capacity as well as high yield strength

  6. Microstructure and corrosion resistance of TC2 Ti alloy by laser cladding with Ti/TiC/TiB{sub 2} powders

    Energy Technology Data Exchange (ETDEWEB)

    Diao, Yunhua, E-mail: 990722012@qq.com; Zhang, Kemin, E-mail: zhangkm@sues.edu.cn

    2015-10-15

    Highlights: • A TiC/TiB{sub 2} composite coating was produced onto a TC2 Ti alloy by laser cladding with Ti/TiC/TiB{sub 2} powders. • A maximum hardness of 1100 HV was achieved in the laser clad TiC/TiB{sub 2} composite layer. • Corrosion resistance of the TC2 alloy in NaCl (3.5 wt%) aqueous solution can be improved after laser cladding. - Abstract: In the present work, a TiC/TiB{sub 2} composite coating was produced onto a TC2 Ti alloy by laser cladding with Ti/TiC/TiB{sub 2} powders. The surface microstructure, phase components and compositions were characterized with methods of optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffractometry (XRD), and energy dispersive spectrometry (EDS). The cladding layer is consisted of Ti, TiC and TiB{sub 2}. And the surface microhardness was measured. After laser cladding, a maximum hardness of 1100 HV is achieved in the laser cladding surface layer, which is more three times higher than that of the TC2 substrate (∼300 HV). Due to the formation of TiC and TiB{sub 2} intermetallic compounds in the alloyed region and grain refinement, the microhardness of coating is higher than TC2 Ti alloy. In this paper, the corrosion property of matrix material and treated samples were both measured in NaCl (3.5 wt%) aqueous solution. From the result we can see that the laser cladding specimens’ corrosion property is clearly becoming better than that of the substrate.

  7. Effect of nano-CeO 2 on microstructure properties of TiC/TiN+TiCN ...

    Indian Academy of Sciences (India)

    TiC/TiN+TiCN-reinforced composite coatings were fabricated on Ti–6Al–4V alloy by laser cladding, which improved surface performance of the substrate. ... X-ray diffraction results indicated that Al3Ti+TiC/TiN+nano-CeO2 laser-cladded coating consisted of Ti3Al, TiC, TiN, Ti2Al20Ce, TiC0.3N0.7, Ce(CN)3 and CeO2, this ...

  8. Microstructure Characteristic of In-situ Ti/TiC Composites

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    TiC reinforced titanium composites has been produced with different Al content and C content by XDTM. The results have shown that TiC particles are of two different morphologies: coarse dendritical primary TiC and short bar-shape eutectic TiC. Al content has great effects on the morphology of TiC. With the increasing of Al content, the morphology of primary TiC changes from coarse developed dendrite into short bar-shape or plate-shape TiC with 35%Al. Meanwhile, the structure of the matrix changes from single Ti to Ti and Ti3Al, and to Ti3Al and TiAl. However, the C content has no influence on the microstructure of matrix. When the C content is less than 1.2%, the dendrite TiC disappears and only short bar-shape or plate-shape TiC exists in the composites. In addition, the effect of heat treatment on the morphology of TiC has also studied.

  9. Synthesis of Nano-Ilmenite (FeTiO3) doped TiO2/Ti Electrode for Photoelectrocatalytic System

    Science.gov (United States)

    Hikmawati; Watoni, A. H.; Wibowo, D.; Maulidiyah; Nurdin, M.

    2017-11-01

    Ilmenite (FeTiO3) doped on Ti and TiO2/Ti electrodes were successfully prepared by using the sol-gel method. The structure, morphology, and optical properties of FeTiO3 are characterized by XRD, UV-Vis DRS, and SEM. The FeTiO3 and TiO2 greatly affect the photoelectrocatalysis performance characterized by Linear Sweep Voltammetry (LSV) and Cyclic Voltammetry (CV). The characterization result shows a band gap of FeTiO3 is 2.94 eV. XRD data showed that FeTiO3 formed at 2θ were 35.1° (110), 49.9° (024), and 61.2° (214). The morphology of FeTiO3/Ti and FeTiO3.TiO2/Ti using SEM shows that the formation of FeTiO3 thin layer signifies the Liquid Phase Deposition method effectively in the coating process. Photoelectrochemical (PEC) test showed that FeTiO3.TiO2/Ti electrode was highly oxidation responsive under visible light compared to the FeTiO3/Ti electrodes i.e. 7.87×10-4 A and 9.87×10-5 A. Degradation test of FeTiO3/Ti and FeTiO3.TiO2/Ti electrodes on titan yellow showed that the percentages of degradation with photoelectrocatalysis at 0.5 mg/L were 41% and 43%, respectively.

  10. Electrosynthesis of Ti5Si3, Ti5Si3/TiC, and Ti5Si3/Ti3SiC2 from Ti-Bearing Blast Furnace Slag in Molten CaCl2

    Science.gov (United States)

    Li, Shangshu; Zou, Xingli; Zheng, Kai; Lu, Xionggang; Chen, Chaoyi; Li, Xin; Xu, Qian; Zhou, Zhongfu

    2018-04-01

    Ti5Si3, Ti5Si3/TiC, and Ti5Si3/Ti3SiC2 have been electrochemically synthesized from the Ti-bearing blast furnace slag/TiO2 and/or C mixture precursors at a cell voltage of 3.8 V and 1223 K to 1273 K (950 °C to 1000 °C) in molten CaCl2. The pressed porous mixture pellets were used as the cathode, and a solid oxide oxygen-ion-conducting membrane (SOM)-based anode was used as the anode. The phase composition and morphologies of the cathodic products were systematically characterized. The final products possess a porous nodular microstructure due to the interconnection of particles. The variations of impurity elements, i.e., Ca, Mg, and Al, have been analyzed, and the result shows that Ca and Mg can be almost completely removed; however, Al cannot be easily removed from the pellet due to the formation of Ti-Al alloys during the electroreduction process. The electroreduction process has also been investigated by the layer-depended phase composition analysis of the dipped/partially reduced pellets to understand the detailed reaction process. The results indicate that the electroreduction process of the Ti-bearing blast furnace slag/TiO2 and/or C mixture precursors can be typically divided into four periods, i.e., (i) the decomposition of initial Ca(Mg,Al)(Si,Al)2O6, (ii) the reduction of Ti/Si-containing intermediate phases, (iii) the removal of impurity elements, and (iv) the formation of Ti5Si3, TiC, and Ti3SiC2. It is suggested that the SOM-based anode process has great potential to be used for the direct and facile preparation of Ti alloys and composites from cheap Ti-containing ores.

  11. 微量TiC对Mo-Ti-Zr-TiC合金性能与显微组织的影响%Effect of Trace TiC on Property and Microstructure of Mo-Ti-Zr-TiC Alloy

    Institute of Scientific and Technical Information of China (English)

    钱昭; 范景莲; 成会朝; 田家敏

    2012-01-01

    采用粉末冶金方法制备Mo-Ti-Zr-TiC合金,研究微量TiC的添加对Mo-Ti-Zr-TiC合金的拉伸性能和显微组织的影响.结果表明,在Mo-Ti-Zr合金中添加微量TiC(0.1%~0.5%,质量分数)后,合金的相对密度和室温抗拉强度得到了提高,当TiC添加量为0.4%时,合金强度最高,较Mo-Ti-Zr合金提高了28.1%.微量TiC的添加,阻碍了合金烧结过程中的晶粒长大,合金晶粒尺寸随TiC添加量的增加而降低.添加的细小TiC粒子在高温烧结过程中或与坯体中的微量氧发生反应形成了由Mo、Ti、C及O 4种元素组成的(Mo,Ti)xOyCz细小复合第二相粒子,或发生团聚结成大颗粒,对合金起到净化晶界氧和弥散强化的作用,因而合金的性能相比Mo-Ti-Zr合金有了较明显的提高.%Mo-Ti-Zr-TiC alloy was prepared via powder metallurgy method. The effects of trace TiC additive on the mechanical properties and microstructure of TiC reinforced Mo-Ti-Zr-TiC alloy were studied. The results indicate that the relative density and the tensile strength at room temperature of Mo-Ti-Zr-TiC alloy is effectively enhanced by adding trace TiC (0.1wt%~0.5wt%). The tensile strength achieves the highest value when the content of TiC is 0.4wt%, which is 28.1% higher than that of Mo-Ti-Zr alloy. The adding of trace TiC can inhibit the grain growth during alloy sintering process, which leads to the decrease of grain sizes with the rise of TiC content. A part of the fine TiC particles react with trace oxygen in molybdenum matrix to form (Mo,Ti)xOyC2 compound second phase particles during high temperature sintering, while the other part are agglomerated into large particles, which play a role in grain boundaries purification and dispersion-strengthening.

  12. The effects of boron in TiAl/Ti3Al

    International Nuclear Information System (INIS)

    Feng, C.R.; Michel, D.J.; Crowe, C.R.

    1989-01-01

    The authors discuss the TiAl/Ti 3 Al interfacial misfit dislocations structures investigated by TEM in Ti-45Al alloy and Ti-45Al/TiB 2 composite. For TiAl with c/a = 1.02, only a single set of misfit dislocation arrays are crystallographically possible; these were observed in Ti-45Al alloy. However, the observation of three sets of misfit dislocation arrays in the Ti-45Al/TiB 2 composite suggests that the occupation of octahedral sites in the TiAl structure by excess boron was responsible for a decrease in the c/a ratio leading to an increased fcc character of the TiAl at the TiAl/Ti 3 Al interface

  13. Liquid phase interaction in TiC0,5N0,5-TiNi-Mo and TiC0,5N0,5-TiNi-Ti-Mo

    International Nuclear Information System (INIS)

    Askarova, L.Kh; Grigorov, I.G.; Zajnulin, Yu.G.

    1998-01-01

    Using the methods of X ray diffraction analysis, electron microscopy and X ray spectrum microanalysis a study was made into specific features of phase and structure formation in alloys TiC 0,5 N 0,5 -TiNi-Mo and TiC 0,5 N 0,5 -TiNi-Mo in the presence of a liquid phase at temperatures of 1380-1600 deg C. It is revealed that the physical and chemical processes taking place during the liquid-phase sintering result in the formation of a three-phase alloy consisting of nonstoichiometric titanium carbonitride TiC 0.5-x N 0.5-x , a molybdenum base solid solution of titanium, nickel and carbon Mo(Ti, Ni, C) and one of two intermetallic compounds, either TiNi or Ni 3 Ti. Metallic element concentration in individual phase constituents of the alloy is determined by means of X ray spectrum microanalysis

  14. Isothermal section of the Ti-Si-B system at 1250 ° C in the Ti-TiSi2-TiB2 region

    OpenAIRE

    Ramos, Alfeu Saraiva; Baldan, Renato; Nunes, Carlos Angelo; Coelho, Gilberto Carvalho; Suzuki, Paulo Atsushi; Rodrigues, Geovani

    2013-01-01

    A partial isothermal section (Ti-TiSi2-TiB2 region) of the ternary Ti-Si-B system at 1250 ° C was determined from heat-treated alloys prepared via arc melting. Microstructural characterization has been carried out through scanning electron microscopy (SEM), x-ray diffraction (xRD) and wavelength dispersive spectrometry (WDS). The results have shown the stability of the near stoichiometric Ti6Si2B phase and a negligible solubility of boron in the Ti-silicides as well as of Si in the Ti-borides...

  15. Fabrication and Mechanical Properties of TiC/TiAl Composites

    Institute of Scientific and Technical Information of China (English)

    YUE Yun-long; GONG Yan-sheng; WU Hai-tao; WANG Chuan-bin; ZHANG Lian-meng

    2004-01-01

    TiC/TiAl composites with different TiC content were fabricated by rapid heating technique ofspark plasma sintering (SPS). The effect of TiC particles on microstructure and mechanical properties of TiAl matrix was investigated. The results indicate that grain sizes of TiAl matrix decrease and mechanical properties are improved because of the addition of TiC particles. The composites display a 26.8% increase in bending strength when10wt% TiC is added and 43.8% improvement in fracture toughness when 5 wt % TiC is added compared to valuesof TiC-free materials. Grain-refinement and dispersion-strengthening were the main strengthening mechanism. Theimprovement of fracture toughness was due to the deflexion of TiC particles to the crack.

  16. Epoxidation of limonene over Ti MCM 41 and Ti BETA

    International Nuclear Information System (INIS)

    Cubillos Lobo, Jairo Antonio; Gonzalez Rodriguez, Lina Maria; Montes de Correa, Consuelo

    2002-01-01

    Ti MCM 41 were synthesized and evaluated in the epoxidation of limonene, using peroxide of hydrogen (H 2 O) as agent oxidizer. The characteristic hexagonal phase of Ti MCM 41 was obtained by heating the precursor gel during three days at 100 centigrade degrees. Further heating up to ten days leads to a decrease of this phase. The increase (Ti) in the synthesis gel also decreases that phase. The increase of Ti in the synthesis gel also decreases that phase UV VIS and FTIR spectroscopy indicates that Ti was incorporated in the lattice of Ti MCM 41 as well as, in Ti BETA. SEM micrographs of Ti MCM 41 show that the morphology changes with the Ti loading. Ti MCM 41 was most active than Ti BETA for limonene epoxidation even though both show high selectivity to epoxides

  17. Microstructural evolution and wear behaviors of laser cladding Ti_2Ni/α(Ti) dual-phase coating reinforced by TiB and TiC

    International Nuclear Information System (INIS)

    Song, R.; Li, J.; Shao, J.Z.; Bai, L.L.; Chen, J.L.; Qu, C.C.

    2015-01-01

    Graphical abstract: - Highlights: • A TiC+TiB reinforced intermetallic matrix coating was fabricated by laser cladding. • The microstructural evolution of the reinforcements was analyzed. • A formula was established in term of wear loss, sliding time and applied load. • Wear behaviors were investigated by in situ continuing tests in different time intervals. • The transformation of wear mechanism at different applied loads was revealed. - Abstract: The Ti_2Ni/α(Ti) dual-phase coating reinforced by TiB and TiC was fabricated on the Ti6Al4V substrate by laser cladding. Phase constituents were confirmed by a theoretical prediction combined with X-ray diffraction (XRD) analyses. From the surface to the bottom of the coating, a regular evolution of the reinforcements’ microstructure, namely TiC_p+(TiB+TiC)_e, (TiB+TiC)_e and TiB_p+(TiB+TiC)_e (p and e were the abbreviations of primary and eutectic, respectively), was investigated by scanning electron microscopy (SEM). The coating possessed the higher microhardness than that of the substrate. An in situ dynamic method (in situ continuing tests at different time intervals) was designed to reveal wear behaviors at different wear stages. A quantitative calculation formula was established by a mathematic model to predict wear losses under different sliding time and applied loads in a definite precision. The wear mechanism was transformed from brittle debonding (at 10 N) to the joint action of brittle debonding and micro-cutting (at 20 N and 30 N) due to the microstructural evolution across the depth from the surface of the coating.

  18. Microstructure of in-situ Synthesized (TiB+TiC)/Ti Composites Prepared by Hot-pressing

    Institute of Scientific and Technical Information of China (English)

    Zhenzhu ZHENG; Lin GENG; Honglin WANG; Weimin ZHOU; Hongyu XU

    2003-01-01

    In-situ 5 vol.pct TiB whiskers and TiC particulates reinforced Ti composites were fabricated by blending Ti powderand B4C particulates followed by reactive hot-pressing. The microstructure of the composites was investigated byusing differential scanning c

  19. Stress analysis and microstructure of PVD monolayer TiN and multilayer TiN/(Ti,Al)N coatings

    NARCIS (Netherlands)

    Carvalho, NJM; Zoestbergen, E; Kooi, BJ; De Hosson, JTM

    2003-01-01

    Two PVD titanium nitride based coatings; monolayer TiN and multilayer resulting from the stacking of TiN and (Ti,Al)N layers were evaluated with respect to their stress state and microstructure. The TiN was deposited by triode evaporation ion plating, whereas the TiN/(Ti,AI)N was deposited using a

  20. Microstructure and Properties of (TiB2 + NiTi)/Ti Composite Coating Fabricated by Laser Cladding

    Science.gov (United States)

    Lin, Yinghua; Lei, Yongping; Fu, Hanguang; Lin, Jian

    2015-10-01

    Agglomerated TiB2 particle and network-like structure-reinforced titanium matrix composite coatings were prepared by laser cladding of the Ni + TiB2 + Ti preplaced powders on Ti-6Al-4V alloy. The network-like structure mainly consisted of NiTi and Ni3Ti. Through the experiment, it was found that the size of agglomerated particle gradually decreased with the increase of Ti content, but the number of the network-like structure first increased and then disappeared. In-situ reaction competition mechanism and the formation of network-like structure were discussed. The average micro-hardness gradually decreased with the increase of Ti content, but the average fracture toughness gradually increased. Meanwhile, the wear resistance of the coatings is higher than that of the substrate, but the wear loss of the coatings is gradually increased with the increase of Ti content.

  1. Antibacterial activity and cell compatibility of TiZrN, TiZrCN, and TiZr-amorphous carbon coatings

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Heng-Li [School of Dentistry, China Medical University, Taichung 404, Taiwan (China); Department of Bioinformatics and Medical Engineering, Asia University, Taichung 41354, Taiwan (China); Chang, Yin-Yu, E-mail: yinyu@nfu.edu.tw [Department of Mechanical and Computer-aided Engineering, National Formosa University, Yunlin 632, Taiwan (China); Liu, Jia-Xu [Department of Mechanical and Computer-aided Engineering, National Formosa University, Yunlin 632, Taiwan (China); Tsai, Ming-Tzu [Department of Biomedical Engineering, Hungkuang University, Taichung 433, Taiwan (China); Lai, Chih-Ho [Department of Microbiology and Immunology, Graduate Institute of Biomedical Sciences, Chang Gung University, Taoyuan, Taiwan (China)

    2015-12-01

    A cathodic-arc evaporation system with plasma-enhanced duct equipment was used to deposit TiZrN, TiZrCN, and TiZr/a-C coatings. Reactive gases (N{sub 2} and C{sub 2}H{sub 2}) activated by the Ti and Zr plasma in the evaporation process was used to deposit the TiZrCN and TiZr/a-C coatings with different C and nitrogen contents. The crystalline structures and bonding states of coatings were analyzed by X-ray diffraction and X-ray photoelectron spectroscopy. The microbial activity of the coatings was evaluated against Staphylococcus aureus (Gram-positive bacteria) and Actinobacillus actinomycetemcomitans (Gram-negative bacteria) by in vitro antibacterial analysis using a fluorescence staining method employing SYTO9 and a bacterial-viability test on an agar plate. The cell compatibility and morphology related to CCD-966SK cell-line human skin fibroblast cells on the coated samples were also determined using the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay, reverse-transcriptase-polymerase chain reaction, and scanning electron microscopy. The results suggest that the TiZrCN coatings not only possess better antibacterial performance than TiZrN and TiZr/a-C coatings but also maintain good compatibility with human skin fibroblast cells. - Highlights: • TiZrN, TiZrCN, and TiZr/a-C coatings were deposited using cathodic arc evaporation. • The TiZrCN showed a composite structure containing TiN, ZrN, and a-C. • The TiZrCN-coated Ti showed the least hydrophobicity among the samples. • The TiZrCN-coated Ti showed good human skin fibroblast cell viability. • The TiZrCN-coated Ti exhibited good antibacterial performance.

  2. Highly uniform bipolar resistive switching characteristics in TiO2/BaTiO3/TiO2 multilayer

    International Nuclear Information System (INIS)

    Ma, W. J.; Zhang, X. Y.; Wang, Ying; Zheng, Yue; Lin, S. P.; Luo, J. M.; Wang, B.; Li, Z. X.

    2013-01-01

    Nanoscale multilayer structure TiO 2 /BaTiO 3 /TiO 2 has been fabricated on Pt/Ti/SiO 2 /Si substrate by chemical solution deposition method. Highly uniform bipolar resistive switching (BRS) characteristics have been observed in Pt/TiO 2 /BaTiO 3 /TiO 2 /Pt cells. Analysis of the current-voltage relationship demonstrates that the space-charge-limited current conduction controlled by the localized oxygen vacancies should be important to the resistive switching behavior. X-ray photoelectron spectroscopy results indicated that oxygen vacancies in TiO 2 play a crucial role in the resistive switching phenomenon and the introduced TiO 2 /BaTiO 3 interfaces result in the high uniformity of bipolar resistive switching characteristics

  3. Study of excited states in 48Ti, 49Ti and 50Ti by means of radiative neutron capture

    International Nuclear Information System (INIS)

    Ruyl, J.F.A.G.

    1983-12-01

    The γ radiation produced by thermal neutron capture in a natural Ti target and in enriched 47 Ti and 49 Ti targets has been investigated. In the analysis 57 excited states of 48 Ti, 28 of 49 Ti and 31 of 50 Ti have been identified. The values for the 48 Ti and 49 Ti neutron binding energy agree with previous data, the value for 50 Ti differs by five standard deviations. The nature of the neutron capture mechanism has been investigated by comparing the present results with those from previous (d,p) work. It appears that in 47 Ti capture proceeds through a doorway state and that the potential capture mechanism is valid for 48 Ti and 49 Ti. The Fermi gas model gives a good representation of the nuclear level density in all three nuclei. From a measurement of the γ-ray circular polarization resulting from the capture of polarized neutrons, combined with previous (d,p) work, the spins of five 49 Ti levels could be determined, and those of 13 other 49 Ti levels could be confirmed. The combination of nuclear orientation measurements and circular polarization measurements had yielded the unambiguous determination of the spins of one 48 Ti state and of five 50 Ti states. Further spin and parity determinations for six 48 Ti and for five 50 Ti states have been obtained from the analysis of the identified branches together with the results of previous experiments. Shell-model calculations, which yielded excitation energies, branching ratios, lifetimes and (d,p) spectroscopic factors, give a good representation of the experimental data for the low-lying states in both even-even nuclei. (Auth.)

  4. Influence of electric current on microstructure evolution in Ti/Al and Ti/TiAl{sub 3} during spark plasma sintering

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Y. [Department of Materials Science and Engineering, Institute of Materials Science, University of Connecticut, Storrs, CT 06269-3136 (United States); Haley, J. [Department of Chemical Engineering and Materials Science, University of California, Davis, CA 95616-5294 (United States); Kulkarni, K. [Department of Materials Science and Engineering, Indian Institute of Technology, Kanpur 208016, UP (India); Aindow, M. [Department of Materials Science and Engineering, Institute of Materials Science, University of Connecticut, Storrs, CT 06269-3136 (United States); Lavernia, E.J., E-mail: lavernia@ucdavis.edu [Department of Chemical Engineering and Materials Science, University of California, Davis, CA 95616-5294 (United States); Department of Chemical Engineering and Materials Science, University of California, Irvine, CA 92697-2575 (United States)

    2015-11-05

    The synthesis of γ-TiAl from elemental metals via solid-state reactive diffusion processing routes involves multiple reaction steps with the formation of various intermediate intermetallic compounds, starting with TiAl{sub 3} because this phase is favored kinetically. To understand the processes by which the TiAl{sub 3} intermediate is eliminated during synthesis of γ-TiAl alloy via spark plasma sintering (SPS), the reaction between Ti and TiAl{sub 3} during SPS was studied with emphasis on the effects of the applied electric current and starting TiAl{sub 3} microstructure on the reaction kinetics and the underlying diffusion mechanisms. The intermediate intermetallic phases Ti{sub 3}Al, TiAl and TiAl{sub 2} were formed between the Ti and TiAl{sub 3} upon SPS processing at 900 °C. The applied electric current did not alter the character of the phases formation in the Ti/TiAl{sub 3} system, but thermodynamic calculations suggest that the activation energy for the nucleation of TiAl{sub 2} is reduced significantly with an electric current flowing. Moreover, the kinetics of the reactions between Ti and TiAl{sub 3} were enhanced when the starting TiAl{sub 3} microstructure was refined. The electric field also had a more significant influence on the grain growth kinetics for TiAl{sub 2} and TiAl in powder blend compacts with refined microstructures. - Highlights: • Reaction between Ti and TiAl{sub 3} during spark plasma sintering was studied. • Refined starting TiAl{sub 3} microstructure enhanced the reactions kinetics. • The nucleation barrier of TiAl{sub 2} was reduced by the applied electric field. • The applied electric field restrained the grain growth of TiAl and TiAl{sub 2}.

  5. Microstructural evolution and wear behaviors of laser cladding Ti{sub 2}Ni/α(Ti) dual-phase coating reinforced by TiB and TiC

    Energy Technology Data Exchange (ETDEWEB)

    Song, R.; Li, J., E-mail: jacob_lijun@sina.com; Shao, J.Z.; Bai, L.L.; Chen, J.L.; Qu, C.C.

    2015-11-15

    Graphical abstract: - Highlights: • A TiC+TiB reinforced intermetallic matrix coating was fabricated by laser cladding. • The microstructural evolution of the reinforcements was analyzed. • A formula was established in term of wear loss, sliding time and applied load. • Wear behaviors were investigated by in situ continuing tests in different time intervals. • The transformation of wear mechanism at different applied loads was revealed. - Abstract: The Ti{sub 2}Ni/α(Ti) dual-phase coating reinforced by TiB and TiC was fabricated on the Ti6Al4V substrate by laser cladding. Phase constituents were confirmed by a theoretical prediction combined with X-ray diffraction (XRD) analyses. From the surface to the bottom of the coating, a regular evolution of the reinforcements’ microstructure, namely TiC{sub p}+(TiB+TiC){sub e}, (TiB+TiC){sub e} and TiB{sub p}+(TiB+TiC){sub e} (p and e were the abbreviations of primary and eutectic, respectively), was investigated by scanning electron microscopy (SEM). The coating possessed the higher microhardness than that of the substrate. An in situ dynamic method (in situ continuing tests at different time intervals) was designed to reveal wear behaviors at different wear stages. A quantitative calculation formula was established by a mathematic model to predict wear losses under different sliding time and applied loads in a definite precision. The wear mechanism was transformed from brittle debonding (at 10 N) to the joint action of brittle debonding and micro-cutting (at 20 N and 30 N) due to the microstructural evolution across the depth from the surface of the coating.

  6. Effect of nano-CeO2 on microstructure properties of TiC/TiN+nTi(CN) reinforced composite coating

    International Nuclear Information System (INIS)

    Jianing, Li; Chuanzhong, Chen; Cuifang, Zhang

    2012-01-01

    TiC/TiN+TiCN reinforced composite coatings were fabricated on Ti-6Al-4V alloy by laser cladding, which improved surface performance of the substrate. Nano-CeO 2 was able to suppress crystallization and growth of the crystals in the laser-cladded coating to a certain extent. With the addition of proper content of nano-CeO 2 , this coating exhibited fine microstructure. In this study, the Al 3 Ti+TiC/TiN+nano-CeO 2 laser-cladded coatings were studied by means of X-ray diffraction and scanning electron microscope. The X-ray diffraction results indicated that the Al 3 Ti+TiC/TiN+nano-CeO 2 laser-cladded coating consisted of Ti 3 Al, TiC, TiN, Ti 2 Al 20 Ce, TiC 0.3 N 0.7 , Ce(CN) 3 and CeO 2 , this phase constituent was beneficial to increase the microhardness and wear resistance of Ti-6Al-6V alloy. (author)

  7. Deposit of thin films of TiN, a-C, Ti/TiN/a-C by laser ablation; Deposito de peliculas delgadas de TiN, a-C, Ti/TiN/a-C por ablacion laser

    Energy Technology Data Exchange (ETDEWEB)

    Mejia, I.S.; Escobar A, L.; Camps, E.; Romero, S. [ININ, 52045 Ocoyoacac, Estado de mexico (Mexico); Muhl, S. [IIM, UNAM, A.P. 364, 01000 Mexico D.F. (Mexico)

    2006-07-01

    Thin films of titanium nitride (TiN), amorphous carbon (a-C), as well as bilayers of Ti/TiN/a-C were deposited by means of the laser ablation technique. It was investigated the effect that it has the laser fluence used to ablation the targets in the structure and mechanical properties of the TiN deposited films. The TiN obtained films have a preferential orientation in the direction (200). The results show that the hardness of this material is influenced by the laser fluence. It is observed that the hardness is increased in an approximately lineal way with the increment of the fluence up to 19 J/cm{sup 2}. The films of amorphous carbon present hardness of the order of 11.2 GPa. Likewise it was found that the multilayers of Ti/TiN/aC presented a bigger hardness that of its individual components. (Author)

  8. A study on wear resistance and microcrack of the Ti3Al/TiAl + TiC ceramic layer deposited by laser cladding on Ti-6Al-4V alloy

    International Nuclear Information System (INIS)

    Li Jianing; Chen Chuanzhong; Squartini, Tiziano; He Qingshan

    2010-01-01

    Laser cladding of the Al + TiC alloy powder on Ti-6Al-4V alloy can form the Ti 3 Al/TiAl + TiC ceramic layer. In this study, TiC particle-dispersed Ti 3 Al/TiAl matrix ceramic layer on the Ti-6Al-4V alloy by laser cladding has been researched by means of X-ray diffraction, scanning electron microscope, electron probe micro-analyzer, energy dispersive spectrometer. The main difference from the earlier reports is that Ti 3 Al/TiAl has been chosen as the matrix of the composite coating. The wear resistance of the Al + 30 wt.% TiC and the Al + 40 wt.% TiC cladding layer was approximately 2 times greater than that of the Ti-6Al-4V substrate due to the reinforcement of the Ti 3 Al/TiAl + TiC hard phases. However, when the TiC mass percent was above 40 wt.%, the thermal stress value was greater than the materials yield strength limit in the ceramic layer, the microcrack was present and its wear resistance decreased.

  9. Study of the preparation of Cu-TiC composites by reaction of soluble Ti and ball-milled carbon coating TiC

    Science.gov (United States)

    Xu, Xuexia; Li, Wenbin; Wang, Yong; Dong, Guozhen; Jing, Shangqian; Wang, Qing; Feng, Yanting; Fan, Xiaoliang; Ding, Haimin

    2018-06-01

    In this work, Cu-TiC composites have been successfully prepared by reaction of soluble Ti and carbon coating TiC. Firstly, the ball milling of graphite and TiC mixtures is used to obtain the carbon coating TiC which has fine size and improved reaction activity. After adding the ball milled carbon coating TiC into Cu-Ti melts, the soluble Ti will easily react with the carbon coating to form TiC. This process will also improve the wettability between Cu melts and TiC core. As a result, besides the TiC prepared by reaction of soluble Ti and carbon coating, the ball milled TiC will also be brought into the melts. Some of these ball-milled TiC particles will go on being coated by the formed TiC from the reaction of Ti and the coating carbon and left behind in the composites. However, most of TiC core will be further reacted with the excessive Ti and be transformed into the newly formed TiC with different stoichiometry. The results indicate that it is a feasible method to synthesize TiC in Cu melts by reaction of soluble Ti and ball-milled carbon coating TiC.

  10. The martensitic transformation in Ti-rich TiNi shape memory alloys

    International Nuclear Information System (INIS)

    Lin, H.C.; Wu, S.K.; Lin, J.C.

    1994-01-01

    The martensitic (Ms) transformation temperatures and their ΔH values of Ti 51 Ni 49 and Ti 50.5 Ni 49.5 alloys are higher than those of equiatomic or Ni-rich TiNi alloys. The Ti-rich TiNi alloys exhibit good shape recovery in spite of a great deal of second phase Ti 2 Ni or Ti 4 Ni 2 O existing around B2 grain boundaries. The nearly identical transformation temperatures indicate that the absorbed oxygen in Ti-rich TiNi alloys may react with Ti 2 Ni particles, instead of the TiNi matrix, to form Ti 4 Ni 2 O. Martensite stabilization can be induced by cold rolling at room temperature. Thermal cycling can depress the transformation temperatures significantly, especially in the initial 20 cycles. The R-phase transformation can be promoted by both cold rolling and thermal cycling in Ti-rich TiNi alloys due to introduced dislocations depressing the Ms temperature. The strengthening effects of cold rolling and thermal cycling on the Ms temperature of Ti-rich TiNi alloys are found to follow the expression Ms = To - KΔσ y . The K values are affected by different strengthening processes and related to the as-annealed transformation temperatures. The higher the as-annealed Ms (or As), the larger the K value. (orig.)

  11. Multilayer TiC/TiN diffusion barrier films for copper

    International Nuclear Information System (INIS)

    Yoganand, S.N.; Raghuveer, M.S.; Jagannadham, K.; Wu, L.; Karoui, A.; Rozgonyi, G.

    2002-01-01

    TiC/TiN thin films deposited by reactive magnetron sputtering on Si (100) substrates were investigated by transmission electron microscopy for microstructure and by deep level transient spectroscopy (DLTS) for diffusion barrier against copper. TiN thin films deposited on Si substrates at a substrate temperature of 600 deg. C were textured, and TiC thin films deposited at the same temperature were polycrystalline. TiC/TiN multilayer films also showed the same characteristics with the formation of an additional interaction layer. The diffusion barrier characteristics of the TiC/TiN/Si were determined by DLTS and the results showed that the films completely prevented diffusion of copper into Si

  12. The Influence of a TiN Film on the Electronic Contribution to the Thermal Conductivity of a TiC Film in a TiN-TiC Layer System

    Science.gov (United States)

    Jagannadham, K.

    2018-01-01

    TiC and TiN films were deposited by reactive magnetron sputtering on Si substrates. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) characterization of the microstructure and interface structure have been carried out and the stoichiometric composition of TiC is determined. Thermal conductivity and interface thermal conductance between different layers in the films are evaluated by the transient thermo reflectance (TTR) and three-omega (3- ω) methods. The results showed that the thermal conductivity of the TiC films increased with temperature. The thermal conductivity of TiC in the absence of TiN is dominated by phonon contribution. The electronic contribution to the thermal conductivity of TiC in the presence of TiN is found to be more significant. The interface thermal conductance of the TiC/TiN interface is much larger than that of interfaces at Au/TiC, TiC/Si, or TiN/Si. The interface thermal conductance between TiC and TiN is reduced by the layer formed as a result of interdiffusion.

  13. Synthesis, microstructure and mechanical properties of Ti3SiC2-TiC composites pulse discharge sintered from Ti/Si/TiC powder mixture

    International Nuclear Information System (INIS)

    Tian Wubian; Sun Zhengming; Hashimoto, Hitoshi; Du Yulei

    2009-01-01

    Ti 3 SiC 2 -TiC composites with the volume fractions of TiC from 0 to 90% were fabricated by pulse discharge sintering (PDS) technique using Ti-Si-TiC as starting powders in the sintering temperature range of 1250-1400 deg. C. Phase content and microstructure of the synthesized samples were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The samples sintered at 1400 deg. C are almost fully dense for all compositions with relative density higher than 98%. The phase distribution in the synthesized samples is non-uniform. The Vickers hardness increases almost linearly with the volume fraction of TiC up to a value of 20.1 ± 1.4 GPa at 90 vol.% TiC. The flexural strength increases with the volume fraction of TiC to a maximum value of 655 ± 10 MPa at 50 vol.% TiC. The relationship between microstructure and mechanical properties is discussed.

  14. Sadhana | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Home; Journals; Sadhana. MING-HSIANG SHIH. Articles written in Sadhana. Volume 33 Issue 6 December 2008 pp 767-779. Development of digital image correlation method to analyse crack variations of masonry wall · Shih-Heng Tung Ming-Hsiang Shih Wen-Pei Sung · More Details Abstract Fulltext PDF. The detection ...

  15. First-Principles Study of the Polar TiC/Ti Interface

    Institute of Scientific and Technical Information of China (English)

    Limin LIU; Shaoqing WANG; Hengqiang YE

    2003-01-01

    The interface structure, work of adhesion, and bonding character of the polar TiC/Ti interface have been examined by the first-principles density functional plane-wave pseudopotential calculations. Both Ti- and C-terminated interfaces including six different interface structures were calculated, which present quite different features. For the Ti-terminated interface, the interfacial Ti-Ti bond has a strong metallic and weak covalent character; while for the C-terminated interface, the interfacial bond is a strong polar covalent interaction between the Ti-3d and C-2p orbital.The work of adhesion of C-terminated interface is nearly 9 J/m2 stronger than that of the Ti-terminated. It is found that each termination has relatively large work of adhesion, which is consistent with other polar interfaces.

  16. Sadhana | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Home; Journals; Sadhana. SHIH-HENG TUNG. Articles written in Sadhana. Volume 33 Issue 6 December 2008 pp 767-779. Development of digital image correlation method to analyse crack variations of masonry wall · Shih-Heng Tung Ming-Hsiang Shih Wen-Pei Sung · More Details Abstract Fulltext PDF. The detection of ...

  17. Sadhana | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Home; Journals; Sadhana. Ming-Hsiang Shih. Articles written in Sadhana. Volume 33 Issue 6 December 2008 pp 767-779. Development of digital image correlation method to analyse crack variations of masonry wall · Shih-Heng Tung Ming-Hsiang Shih Wen-Pei Sung · More Details Abstract Fulltext PDF. The detection of ...

  18. A study on wear resistance and microcrack of the Ti{sub 3}Al/TiAl + TiC ceramic layer deposited by laser cladding on Ti-6Al-4V alloy

    Energy Technology Data Exchange (ETDEWEB)

    Li Jianing, E-mail: ljnljn1022@163.com [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education), Department of Materials Science, Shandong University, Jing Shi Road 17923, Jinan 250061, Shandong (China); Chen Chuanzhong [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Department of Materials Science, Shandong University, Jing Shi Road 17923, Jinan 250061, Shandong (China); Squartini, Tiziano [INFM-Department of Physics, Siena University, Siena 53100 (Italy); He Qingshan [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Department of Materials Science, Shandong University, Jing Shi Road 17923, Jinan 250061, Shandong (China)

    2010-12-15

    Laser cladding of the Al + TiC alloy powder on Ti-6Al-4V alloy can form the Ti{sub 3}Al/TiAl + TiC ceramic layer. In this study, TiC particle-dispersed Ti{sub 3}Al/TiAl matrix ceramic layer on the Ti-6Al-4V alloy by laser cladding has been researched by means of X-ray diffraction, scanning electron microscope, electron probe micro-analyzer, energy dispersive spectrometer. The main difference from the earlier reports is that Ti{sub 3}Al/TiAl has been chosen as the matrix of the composite coating. The wear resistance of the Al + 30 wt.% TiC and the Al + 40 wt.% TiC cladding layer was approximately 2 times greater than that of the Ti-6Al-4V substrate due to the reinforcement of the Ti{sub 3}Al/TiAl + TiC hard phases. However, when the TiC mass percent was above 40 wt.%, the thermal stress value was greater than the materials yield strength limit in the ceramic layer, the microcrack was present and its wear resistance decreased.

  19. Fretting wear behaviour of TiC/Ti(C,N)/TiN multi-layer coatings at elevated temperature in gross slip regime

    International Nuclear Information System (INIS)

    Liu Hanwei; Huang Kunpeng; Zhu Minhao; Zhou Zhongrong

    2005-01-01

    Tic/Ti(C,N)/TiN multi-layer coatings are prepared on the 1Cr13 stainless steel substrate by the technique of Chemical Vapour Deposition, and the fretting wear behaviour of 1Cr13 stainless steel and TiC/Ti(C,N)/TiN coatings are investigated and studied controversially from 25 degree C to 400 degree C in the gross slip regime. It shows that the temperature has great influence on the fretting wear in the gross slip regime for the 1Cr13 stainless steel but little for Ti/C/Ti(C,N)/TiN multi-layer coatings. With the temperature increasing, the friction coefficient and the wear volume of the 1Cr13 alloy decreases and the wear volume of TiC/Ti(C, N)/TiN multi-layer coatings is invariant. TiC/Ti(C,N)/TiN multi-layer coatings have better wear-resistant capability than the 1Cr13 stainless steel, but the wear volume of the substrate increases greatly because of the grain-abrasion resulted from hard debris when TiC/Ti(C,N)/TiN multi-layer coatings are ground off. (authors)

  20. Tailoring ultrafine grained and dispersion-strengthened Ti 2 AlC/TiAl ...

    Indian Academy of Sciences (India)

    In situ Ti 2 AlC/TiAl composite was fabricated by hot-pressing method via the reaction system of Ti 3 AlC 2 and Ti-Al pre-alloyed powders at low temperature of 1150 ∘ C. The composite mainly consisted of TiAl, Ti 3 Al and Ti 2 AlC phases. Fine Ti 2 AlC particles were homogeneously distributed and dispersed in the matrix.

  1. Structure, phase composition and microhardness of vacuum-arc multilayered Ti/Al, Ti/Cu, Ti/Fe, Ti/Zr nano-structures with different periods

    Energy Technology Data Exchange (ETDEWEB)

    Demchishin, A.V., E-mail: ademch@meta.ua [Institute of Problems in Material Science, NASU, Kiev (Ukraine); Gnilitskyi, I., E-mail: iaroslav.gnilitskyi@unimore.it [DISMI – Department of Sciences and Methods for Engineering, University of Modena and Reggio Emilia, Reggio Emilia (Italy); Orazi, L., E-mail: leonardo.orazi@unimore.it [DISMI – Department of Sciences and Methods for Engineering, University of Modena and Reggio Emilia, Reggio Emilia (Italy); Ascari, A., E-mail: a.ascari@unibo.it [DIN – Department of Industrial Engineering, University of Bologna, Bologna (Italy)

    2015-07-01

    Highlights: • Multilayer coatings of Ti/Fe, Ti/Al, Ti/Cu and Ti/Zr are generated. • Microstructure and morphology of the different systems are investigated. • XR diffraction analysis was performed to investigate phases composition. • Effects of inter metallic phases on microhardess are investigated. • Correlations between parameters and layer thickness are outlined. - Abstract: The microstructure, phase composition and microhardness of multilayered Ti/Al, Ti/Cu, Ti/Fe and Ti/Zr condensates produced on stainless steel substrates via vacuum-arc evaporation of pure metals were studied. The sublayer periods (Λ) were regulated in the range 80–850 nm by varying the vacuum discharge current and the duration of the successive depositions of metallic plasma onto the substrates while maintaining the total deposition time constant. The regularity of the obtained nanostructures was investigated by scanning and transmission electron microscopy while phase compositions were identified with X-ray diffraction (XRD) analysis in order to evidence the presence of interdiffusion and the amount of intermetallics. Condensates cross sections were mechanically characterized by means of microhardness tests. Measurements were correlated to the periods and to the presence of intermetallics.

  2. Structure, phase composition and microhardness of vacuum-arc multilayered Ti/Al, Ti/Cu, Ti/Fe, Ti/Zr nano-structures with different periods

    International Nuclear Information System (INIS)

    Demchishin, A.V.; Gnilitskyi, I.; Orazi, L.; Ascari, A.

    2015-01-01

    Highlights: • Multilayer coatings of Ti/Fe, Ti/Al, Ti/Cu and Ti/Zr are generated. • Microstructure and morphology of the different systems are investigated. • XR diffraction analysis was performed to investigate phases composition. • Effects of inter metallic phases on microhardess are investigated. • Correlations between parameters and layer thickness are outlined. - Abstract: The microstructure, phase composition and microhardness of multilayered Ti/Al, Ti/Cu, Ti/Fe and Ti/Zr condensates produced on stainless steel substrates via vacuum-arc evaporation of pure metals were studied. The sublayer periods (Λ) were regulated in the range 80–850 nm by varying the vacuum discharge current and the duration of the successive depositions of metallic plasma onto the substrates while maintaining the total deposition time constant. The regularity of the obtained nanostructures was investigated by scanning and transmission electron microscopy while phase compositions were identified with X-ray diffraction (XRD) analysis in order to evidence the presence of interdiffusion and the amount of intermetallics. Condensates cross sections were mechanically characterized by means of microhardness tests. Measurements were correlated to the periods and to the presence of intermetallics

  3. Preparation and solar-light photocatalytic activity of TiO2 composites: TiO2/kaolin, TiO2/diatomite, and TiO2/zeolite

    Science.gov (United States)

    Li, Y.; Li, S. G.; Wang, J.; Li, Y.; Ma, C. H.; Zhang, L.

    2014-12-01

    Three TiO2 loaded composites, TiO2/kaolin, TiO2/diatomite, and TiO2/zeolite, were prepared in order to improve the solar-light photocatalytic activity of TiO2. The results showed that the photocatalytic activity could obviously be enhanced by loading appropriate amount of inorganic mineral materials. Meanwhile, TiO2 content, heat-treatment temperature and heat-treatment time on the photocatalytic activity were reviewed. Otherwise, the effect of solar light irradiation time and dye concentration on the photocatalytic degradation of Acid Red B was investigated. Furthermore, the degradation mechanism and adsorption process were also discussed.

  4. Photoelectrocatalytic property of microporous Pt-TiO2/Ti electrodes

    International Nuclear Information System (INIS)

    Hung, Chung-Hsuang; Wu, Kee-Rong; Yeh, Chung-Wei; Sun, Jui-Ching; Hsu, Chuan-Jen

    2013-01-01

    This study investigates the photoelectrocatalytic (PEC) property of microporous WO 3 -loaded TiO 2 /Ti layer, prepared via micro-arc oxidation (MAO) of Ti plate, followed by sputtering deposition of a thin Pt layer as a Pt-TiO 2 /Ti electrode. The WO 3 -loaded TiO 2 layer which is associated with a more acidic surface forms many local electrochemical cells on its micro-pores immersed in cationic dye solution. The electrocatalytic (EC) reactions can take place in the local cells by the applied electrons. A low resistivity that is accomplished by MAO technique and by platinization offers an easy path for the electron motions in the Pt-TiO 2 /Ti electrode. All these features make the EC oxidation of aqueous dye pollutants practically feasible without using counter electrodes and supporting electrolytes. Our experiments demonstrate that, under PEC condition, the Pt-TiO 2 /Ti shows the highest degradation rate constant of 0.83 h − 1 at an applied bias of 1.0 V and exhibits significantly high PEC and EC oxidation activities at a low applied bias of 0.25 V. This is attributable to high anodic currents generated in the Pt-TiO 2 /Ti even at low bias. The modified microporous electrodes conclusively reveal a very interesting EC property as a two double-sided device that functions the PEC and EC oxidation simultaneously without a need of supporting electrolyte and expensive Pt cathode. - Highlights: ► Pt-TiO 2 /Ti exhibits enhanced photoelectrocatalytic (PEC) activity at low applied bias. ► The proposed device uses low applied bias (< 1.0 V) with no explicit cathode. ► PEC oxidation can be performed without supporting electrolyte and Pt cathode

  5. Electron densities and chemical bonding in TiC, TiN and TiO derived from energy band calculations

    International Nuclear Information System (INIS)

    Blaha, P.

    1983-10-01

    It was the aim of this paper to describe the chemical bonding of TiC, TiN and TiO by means of energy bands and electron densities. Using the respective potentials we have calculated the bandstructure of a finer k-grid with the linearized APW method to obtain accurate densities of states (DOS). These DOS wer partitioned into local partial contributions and the metal d DOS were further decomposed into tsub(2g) and esub(g) symmetry components in order to additionally characterize bonding. The electron densities corresponding to the occupied valence states are obtained from the LAPW calculations. They provide further insight into characteristic trends in the series from TiC to TiO: around the nonmetal site the density shows increasing localisation; around the metal site the deviation from spherical symmetry changes from esub(g) to tsub(2g). Electron density plots of characteristic band states allow to describe different types of bonding occurring in these systems. For TiC and TiN recent measurements of the electron densities exist for samples of TiCsub(0.94) and TiNsub(0.99), where defects cause static displacements of the Ti atoms. If this effect can be compensated by an atomic model one hopefully can extrapolate to stoichiometric composition. This procedure allows a comparison with structure factors derived from theoretical electron densities. The agreement for TiN is very good. For TiC the extrapolated data agree in terms of the deviations from spherical symmetry near the Ti site with the LAPW data, but the densities around both atoms are more localized than in theory. An explanation could be: a) the defects affect the electronic structure in TiCsub(0.94) with respect to TiCsub(1.0): b) the applied atomic model does not properly extrapolate to stoichiometry, because parameters of this model correlate or become unphysical. (Author)

  6. TEM characterization of a Cr/Ti/TiC graded interlayer for magnetron-sputtered TiC/a-C:H nanocomposite coatings

    International Nuclear Information System (INIS)

    Galvan, D.; Pei, Y.T.; De Hosson, J.Th.M.

    2005-01-01

    A TiC/a-C:H nanocomposite coating is deposited on top of a Cr/Ti/TiC graded interlayer. Cross-section transmission electron microscopy is employed to investigate the detailed structure of the interlayer and the coating. Five different phases are formed as a consequence of the compositional gradient within the interlayer: pure Cr, a solid solution of Ti in Cr, a Ti/Cr amorphous/nanocrystalline phase, α-Ti and TiC. Solid state amorphization occurs during the interlayer deposition to give a dispersion of TiCr β-phase nanocrystals in an amorphous matrix. The TiC phase is textured and contains numerous stacking faults as a result of the growth in under-stoichiometric carbon concentration. C-enriched columnar boundaries are present within the coating, originating from the TiC column boundaries of the interlayer. The work indicates that an interlayer of amorphous/nanocrystalline Ti/Cr phase would reduce the presence of growth defects such as columnar boundaries within nanocomposite TiC/a-C:H coatings

  7. Stability of tritium permeation prevention barrier with TiC and TiN + TiC coating

    International Nuclear Information System (INIS)

    Shan Changqi; Chen Qingwang; Dai Shaoxia; Jiang Weisheng

    1999-01-01

    The stability of tritium permeation prevention barrier of 316L stainless steel with coating TiC and TiN + TiC under the conditions of very large thermal gradient, thermal cycling and plasma irradiation is researched. The research includes two aspects: one is the study on the stability resisting H + plasma irradiation; another is on the ability of two coating materials when they are used in long term under the condition of very large thermal gradient and cycling. The results show that TiC and TiN + TiC composite coating materials, after chemical heat treatment and forming tritium permeation prevention barrier, can resist H + ion irradiation, and also can resist very large thermal gradient and thermal cycling. The long time experiments show that tritium permeation prevention barrier of those coating materials is stable when they are used in long term

  8. Evaluated (n,p) cross sections of 46Ti, 47Ti and 48Ti

    International Nuclear Information System (INIS)

    Philis, C.; Bersillon, O.; Smith, D.; Smith, A.

    1977-01-01

    Microscopic evaluated neutron cross sections for the reactions 46 Ti(n;p) 46 Sc, 47 Ti(n;p) 47 Sc and 48 Ti(n;p) 48 Sc are obtained from threshold (or zero energy) to 20 MeV. The results are presented in graphical and numerical (ENDF format) form. The microscopic evaluated cross sections are compared with measured fission-spectrum-averaged values

  9. In situ preparation of (TiB + TiC + Nd2O3)/Ti composites by powder metallurgy

    International Nuclear Information System (INIS)

    Lu Junqiang; Qin Jining; Lu Weijie; Liu Yang; Gu Jiajun; Zhang Di

    2009-01-01

    Titanium matrix composites reinforced with multiple ceramic particulates TiB, TiC and Nd 2 O 3 were prepared by powder metallurgy utilizing the chemical reactions among Ti, B 4 C, NdB 6 and oxygen in Ti powder. The thermodynamic feasibility of the in situ reaction has been calculated. The phases were identified by X-ray diffraction (XRD). The result shows that multiple ceramic phases TiB, TiC and Nd 2 O 3 particulates have been synthesized. The microstructures were examined by means of optical microscopy (OM), scanning electron microscopy (SEM), backscattered electron microscopy and transmission electron microscope (TEM). The results show that the reinforcements are distributed uniformly in the matrix alloy and grow in different shapes. TiB grows in needle shape; TiC and Nd 2 O 3 grow in equiaxed or near-equiaxed shapes. The addition of NdB 6 is beneficial to grain refinement, grain-boundary purification and porosity reduction

  10. Nitrogen implantation of Ti and Ti+Al films deposited on tool steel

    International Nuclear Information System (INIS)

    Huang, C.-T.; Duh, J.-G.

    1995-01-01

    Titanium and aluminum thin films were deposited onto A2 steel by rf magnetron sputtering with various Al contents. The coated assembly was then implanted with nitrogen ions at 92 kV and 1 mA for 4.5 h. The thickness of the implanted Ti and Ti+Al films deposited for 1 h was around 0.4-0.5 μm. With the aid of X-ray diffraction by the grazing-incidence technique, secondary ion mass spectrum (SIMS) and X-ray photoelectron spectroscopy (XPS), the titanium oxide and titanium nitride were identified on the top and inner surface in the implanted Ti film. For Ti+Al films after nitrogen implantation, Ti 3 O 5 was formed on the top surface beneath which is a (Ti, Al) N solid solution. There was Ti 2 N compound formed in the implanted Ti film, while only a minor amount of Ti 2 N phase was observed in the inner region in the implanted Ti+Al film. The nitrogen distribution was flattened and spread in the implanted Ti film, while a concentration gradient was observed in the Ti+Al film after implantation. The measured surface hardness of implanted Ti film was higher than those of Ti+Al films and the hardness of implanted Ti+39%Al film was enhanced as compared to the Ti+50%Al film. (Author)

  11. Evolution process of the synthesis of TiC in the Cu-Ti-C system

    International Nuclear Information System (INIS)

    Liang, Y.H.; Wang, H.Y.; Yang, Y.F.; Wang, Y.Y.; Jiang, Q.C.

    2008-01-01

    The evolution process of TiC formation in the 20 wt.% Cu-Ti-C powder mixtures was studied by using differential thermal analysis (DTA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The Ti x Cu y compounds (Ti 2 Cu, TiCu, Ti 3 Cu 4 and TiCu 4 ) formed initially via solid-state diffusion reactions between Cu and Ti particles; and then Ti 2 Cu and TiCu can form a Cu-Ti eutectic liquids at about 1233 K. The unreacted Ti and C particles dissolved into the Cu-Ti liquids and led to the formation of Cu-Ti-C ternary liquids; subsequently, TiC particulates precipitated out of the saturated liquids. At the same time, also the formation of Ti 2 Cu occurred at the interface between the Cu-Ti liquids and the unreacted Ti particles. As the temperature increased further, the Ti 2 Cu melted and more Cu-Ti liquids formed; and then C particles continuously dissolved into the Cu-Ti-C liquids and TiC particulates gradually precipitated out of the saturated liquids

  12. Fabrication and Characterization of New Ti-TiO2-Al and Ti-TiO2--Pt Tunnel Diodes

    Directory of Open Access Journals (Sweden)

    Yaksh Rawal

    2012-01-01

    Full Text Available Remotely empowered wireless sensor networks use different energy resources including photovoltaic solar cells, wireless power transmission, and batteries. As another option the electromagnetic energy available in the ambient can be harvested to power these remote sensors. This is particularly valuable if it is desirable to harvest the ambient energy available in the wide range of electromagnetic spectrum. This has motivated the research for developing energy harvesting devices which can absorb this energy and produce a DC voltage. Rectenna, an antenna coupled with a rectifier, is the main component used for absorbing electromagnetic radiation at GHz and THz frequencies. Rectifying MIM tunnel diodes are able to operate at tens and hundreds of GHz frequency. As the preliminary steps towards development of high-frequency rectifiers, this paper presents fabrication and DC characterization of two new MIM diodes, Ti-TiO2-Al and Ti-TiO2-Pt. G-V analysis of the fabricated diodes verifies tunneling. Brinkman-Dynes-Rowell model is used to extract oxide thickness of which the derived value is around 9 nm. Ti-TiO2-Pt diode exhibits rectification ratio of 15 at 0.495 V, which is more than rectification ratio reported in earlier works.

  13. TiC/Ti3SiC2复合材料的制备及其性能研究%Preparation and properties of TiC/Ti3SiC2 composites

    Institute of Scientific and Technical Information of China (English)

    贾换; 尹洪峰; 袁蝴蝶; 杨祎诺

    2012-01-01

    以粉末Ti,Si,TiC和炭黑为原料,采用反应热压烧结法制备TiC/Ti3SiC2复合材料.借助XRD和SEM研究TiC含量对TiC/Ti3SiC2复合材料相组成、显微结构及力学特性的影响.结果表明:通过热压烧结可以得到致密度较高的TiC/Ti3SiC2复合材料;引入TiC可以促进Ti3SiC2的生成,当引入TiC的质量分数达30%,TiC/Ti3SiC2复合材料的弯曲强度和断裂韧性分别为406.9 MPa,3.7 MPa·m1/2;复合材料中Ti3SiC2相以穿晶断裂为主,TiC晶粒易产生拔出.%TiC/Ti3SiC2 composites were fabricated by reactive hot pressing sintering method using the mixture powder of Ti, Si, C and TiC as raw material. The effect of TiC content on phase composition, microstructure and mechanical properties of TiC/Ti3SiC2 composites was investigated by X-ray diffraction and scanning electron microscopy. The results demonstrate that dense TiC/ Ti3SiC2 composites can be obtained by hot pressing. The addition of TiC into composites can enhance the formation of TisSiC2. When the additional content of TiC reaches 30% (mass fraction) , the flexural strength and fracture toughness of TiC/Ti3SiC2 composite are 406.9 MPa and 3.7 MPa·m-2, respectively. Ti3SiC2 phase displays intergranular fracture and TiC grain pulls out from Ti3SiC2 matrix when TiC/Ti3SiC2 composite fractures.

  14. Controllable hydrothermal synthesis of rutile TiO2 hollow nanorod arrays on TiCl4 pretreated Ti foil for DSSC application

    International Nuclear Information System (INIS)

    Xi, Min; Zhang, Yulan; Long, Lizhen; Li, Xinjun

    2014-01-01

    Rutile TiO 2 nanorod arrays (TNRs) were achieved by hydrothermal process on TiCl 4 pretreated Ti foil. Subsequently, TNRs were hydrothermally etched in HCl solution to form hollow TiO 2 nanorod arrays (H-TNRs). The TiCl 4 pretreatment plays key roles in enhancement of Ti foil corrosion resistance ability and crystal nucleation introduction for TNRs growth. TNRs with desired morphology can be obtained by controlling TiCl 4 concentration and the amount of tetrabutyl titanate (TTB) accordingly. TNRs with the length of ∼1.5 μm and diameter of ∼200 nm, obtained on 0.15 M TiCl 4 pretreated Ti foil with 0.6 mL TTB, exhibits relatively higher photocurrent. The increased pore volume of the H-TNRs has contributed to the increased surface area which is benefit for Dye-Sensitized Solar Cells (DSSC) application. And the 180 °C-H-TNRs photoanode obtained from the 0.15-TiCl 4 -TNRs sample demonstrated 128.9% enhancement of photoelectric efficiency of DSSC compared to that of the original TNR photoanode. - Graphical abstract: Rutile hollow TiO 2 nanorod array photoanode obtained from original TiO 2 nanorod array photoanode by hydrothermal etching demonstrates enhanced photoelectric efficiency of DSSC. - Highlights: • TiO 2 nanorods are prepared via hydrothermal process on TiCl 4 -pretreated Ti foil. • Hollow TiO 2 nanorods are obtained by hydrothermal etching of TiO 2 nanorods. • TiCl 4 pretreatment plays a key role in protecting Ti foil from chemical corrosion. • Hollow TiO 2 nanorods photoanode shows enhanced photoelectric efficiency for DSSC

  15. Phase Constituents and Microstructure of Ti3Al/Fe3Al + TiN/TiB2 Composite Coating on Titanium Alloy

    Science.gov (United States)

    Li, Jianing; Chen, Chuanzhong; Zhang, Cuifang

    Laser cladding of the Fe3Al + B4C/TiN + Al2O3 pre-placed powders on the Ti-6Al-4V alloy can form the Ti3Al/Fe3Al + TiN/TiB2 composite coating, which improved the wear resistance of the Ti-6Al-4V alloy surface. In this study, the Ti3Al/Fe3Al + TiN/TiB2 composite coating has been researched by means of X-ray diffraction and scanning electron microscope. It was found that during the laser cladding process, Al2O3 can react with TiB2, leading to the formations of Ti3Al and B. This principle can be used to improve the Fe3Al + B4C/TiN laser-cladded coating on the Ti-6Al-4V alloy. Furthermore, during the cladding process, C consumed the oxygen in Fe3Al + B4C /TiN + Al2O3 molten pool, which retarded the productions of the redundant metal oxides.

  16. PHASE CONSTITUENTS AND MICROSTRUCTURE OF Ti3Al/Fe3Al + TiN/TiB2 COMPOSITE COATING ON TITANIUM ALLOY

    OpenAIRE

    JIANING LI; CHUANZHONG CHEN; CUIFANG ZHANG

    2011-01-01

    Laser cladding of the Fe3Al + B4C/TiN + Al2O3 pre-placed powders on the Ti-6Al-4V alloy can form the Ti3Al/Fe3Al + TiN/TiB2 composite coating, which improved the wear resistance of the Ti-6Al-4V alloy surface. In this study, the Ti3Al/Fe3Al + TiN/TiB2 composite coating has been researched by means of X-ray diffraction and scanning electron microscope. It was found that during the laser cladding process, Al2O3 can react with TiB2, leading to the formations of Ti3Al and B. This principle can be...

  17. The dynamics of TiN{sub x} (x = 1–3) admolecule interlayer and intralayer transport on TiN/TiN(001) islands

    Energy Technology Data Exchange (ETDEWEB)

    Edström, D., E-mail: daned@ifm.liu.se [Department of Physics, Chemistry and Biology (IFM), Linköping University, SE-58183 Linköping (Sweden); Sangiovanni, D.G.; Hultman, L. [Department of Physics, Chemistry and Biology (IFM), Linköping University, SE-58183 Linköping (Sweden); Petrov, I.; Greene, J.E. [Department of Physics, Chemistry and Biology (IFM), Linköping University, SE-58183 Linköping (Sweden); Frederick Seitz Materials Research Laboratory and the Materials Science Department, University of Illinois at Urbana-Champaign, Urbana, IL 61801 (United States); Chirita, V. [Department of Physics, Chemistry and Biology (IFM), Linköping University, SE-58183 Linköping (Sweden)

    2015-08-31

    It has been shown both experimentally and by density functional theory calculations that the primary diffusing species during the epitaxial growth of TiN/TiN(001) are Ti and N adatoms together with TiN{sub x} complexes (x = 1, 2, 3), in which the dominant N-containing admolecule species depends upon the incident N/Ti flux ratio. Here, we employ classical molecular dynamics (CMD) simulations to probe the dynamics of TiN{sub x} (x = 1–3) admolecules on 8 × 8 atom square, single-atom-high TiN islands on TiN(001), as well as pathways for descent over island edges. The simulations are carried out at 1000 K, a reasonable epitaxial growth temperature. We find that despite their lower mobility on infinite TiN(001) terraces, both TiN and TiN{sub 2} admolecules funnel toward descending steps and are incorporated into island edges more rapidly than Ti adatoms. On islands, TiN diffuses primarily via concerted translations, but rotation is the preferred diffusion mechanism on infinite terraces. TiN{sub 2} migration is initiated primarily by rotation about one of the N admolecule atoms anchored at an epitaxial site. TiN admolecules descend from islands by direct hopping over edges and by edge exchange reactions, while TiN{sub 2} trimers descend exclusively by hopping. In contrast, TiN{sub 3} admolecules are essentially stationary and serve as initiators for local island growth. Ti adatoms are the fastest diffusing species on infinite TiN(001) terraces, but on small TiN/TiN(001) islands, TiN dimers provide more efficient mass transport. The overall results reveal the effect of the N/Ti precursor flux ratio on TiN(001) surface morphological evolution and growth modes. - Highlights: • Classical MD is used to model TiN{sub x} admolecule dynamics on TiN/TiN(001) islands. • TiN{sub x} admolecules descend from islands by both direct hopping and exchange reactions. • TiN and TiN{sub 2} exhibit surprisingly high diffusivities on TiN/TiN(001) islands. • TiN{sub 3} tetramers are

  18. Study of preparation of TiB2 by TiC in Al melts

    International Nuclear Information System (INIS)

    Ding Haimin; Liu Xiangfa; Nie Jinfeng

    2012-01-01

    TiB 2 particles are prepared by TiC in Al melts and the characteristics of them are studied. It is found that TiC particles are unstable when boron exists in Al melts with high temperature and will transform to TiB 2 and Al 4 C 3 . Most of the synthesized TiB 2 particles are regular hexagonal prisms with submicron size. The diameter of the undersurfaces of these prisms is ranging from 200 nm to 1 μm and the height is ranging from 100 nm to 300 nm. It is considered that controlling the transformation from TiC to TiB 2 is an effective method to prepare small and uniform TiB 2 particles. - Highlights: ► TiC can easily transform into TiB 2 in Al melts. ► TiB 2 formed by TiC will grow into regular hexagonal prisms with submicron size. ► Controlling the transformation from TiC to TiB 2 is an effective method to prepare small and uniform TiB 2 particles.

  19. The Formation Time of Ti-O• and Ti-O•-Ti Radicals at the n-SrTiO3/Aqueous Interface during Photocatalytic Water Oxidation.

    Science.gov (United States)

    Chen, Xihan; Choing, Stephanie N; Aschaffenburg, Daniel J; Pemmaraju, C D; Prendergast, David; Cuk, Tanja

    2017-02-08

    The initial step of photocatalytic water oxidation reaction at the metal oxide/aqueous interface involves intermediates formed by trapping photogenerated, valence band holes on different reactive sites of the oxide surface. In SrTiO 3, these one-electron intermediates are radicals located in Ti-O • (oxyl) and Ti-O • -Ti (bridge) groups arranged perpendicular and parallel to the surface respectively, and form electronic states in the band gap of SrTiO 3 . Using an ultrafast sub band gap probe of 400 nm and white light, we excited transitions between these radical states and the conduction band. By measuring the time evolution of surface reflectivity following the pump pulse of 266 nm light, we determined an initial radical formation time of 1.3 ± 0.2 ps, which is identical to the time to populate the surface with titanium oxyl (Ti-O • ) radicals. The oxyl was separately observed by a subsurface vibration near 800 cm -1 from Ti-O located in the plane right below Ti-O • . Second, a polarized transition optical dipole allows us to assign the 1.3 ps time constant to the production of both O-site radicals. After a 4.5 ps delay, another distinct surface species forms with a time constant of 36 ± 10 ps with a yet undetermined structure. As would be expected, the radicals' decay, specifically probed by the oxyl's subsurface vibration, parallels that of the photocurrent. Our results led us to propose a nonadiabatic kinetic mechanism for generating radicals of the type Ti-O • and Ti-O • -Ti from valence band holes based on their solvation at aqueous interfaces.

  20. Ti and N adatom descent pathways to the terrace from atop two-dimensional TiN/TiN(001) islands

    Energy Technology Data Exchange (ETDEWEB)

    Edström, D., E-mail: daned@ifm.liu.se [Department of Physics, Chemistry and Biology (IFM), Linköping University, SE-58183 Linköping (Sweden); Sangiovanni, D.G.; Hultman, L.; Chirita, V. [Department of Physics, Chemistry and Biology (IFM), Linköping University, SE-58183 Linköping (Sweden); Petrov, I.; Greene, J.E. [Department of Physics, Chemistry and Biology (IFM), Linköping University, SE-58183 Linköping (Sweden); Frederick Seitz Materials Research Laboratory and the Materials Science Department, University of Illinois at Urbana-Champaign, Urbana, IL 61801 (United States)

    2014-05-02

    We use classical molecular dynamics and the modified embedded atom method to determine residence times and descent pathways of Ti and N adatoms on square, single-atom-high, TiN islands on TiN(001). Simulations are carried out at 1000 K, which is within the optimal range for TiN(001) epitaxial growth. Results show that the frequency of descent events, and overall adatom residence times, depend strongly on both the TiN(001) diffusion barrier for each species as well as the adatom island-edge location immediately prior to descent. Ti adatoms, with a low diffusion barrier, rapidly move toward the island periphery, via funneling, where they diffuse along upper island edges. The primary descent mechanism for Ti adatoms is via push-out/exchange with Ti island-edge atoms, a process in which the adatom replaces an island edge atom by moving down while pushing the edge atom out onto the terrace to occupy an epitaxial position along the island edge. Double push-out events are also observed for Ti adatoms descending at N corner positions. N adatoms, with a considerably higher diffusion barrier on TiN(001), require much longer times to reach island edges and, consequently, have significantly longer residence times. N adatoms are found to descend onto the terrace by direct hopping over island edges and corner atoms, as well as by concerted push-out/exchange with N atoms adjacent to Ti corners. For both adspecies, we also observe several complex adatom/island interactions, before and after descent onto the terrace, including two instances of Ti island-atom ascent onto the island surface. - Highlights: • We use classical molecular dynamics to model Ti and N adatom migration on TiN(001) islands. • N adatoms remain on islands significantly longer than Ti adatoms. • Ti adatoms descend via push-out/exchange, N adatoms primarily by direct hops. • N adatoms act as precursors for multilayer formation and surface roughening.

  1. Ti and N adatom descent pathways to the terrace from atop two-dimensional TiN/TiN(001) islands

    International Nuclear Information System (INIS)

    Edström, D.; Sangiovanni, D.G.; Hultman, L.; Chirita, V.; Petrov, I.; Greene, J.E.

    2014-01-01

    We use classical molecular dynamics and the modified embedded atom method to determine residence times and descent pathways of Ti and N adatoms on square, single-atom-high, TiN islands on TiN(001). Simulations are carried out at 1000 K, which is within the optimal range for TiN(001) epitaxial growth. Results show that the frequency of descent events, and overall adatom residence times, depend strongly on both the TiN(001) diffusion barrier for each species as well as the adatom island-edge location immediately prior to descent. Ti adatoms, with a low diffusion barrier, rapidly move toward the island periphery, via funneling, where they diffuse along upper island edges. The primary descent mechanism for Ti adatoms is via push-out/exchange with Ti island-edge atoms, a process in which the adatom replaces an island edge atom by moving down while pushing the edge atom out onto the terrace to occupy an epitaxial position along the island edge. Double push-out events are also observed for Ti adatoms descending at N corner positions. N adatoms, with a considerably higher diffusion barrier on TiN(001), require much longer times to reach island edges and, consequently, have significantly longer residence times. N adatoms are found to descend onto the terrace by direct hopping over island edges and corner atoms, as well as by concerted push-out/exchange with N atoms adjacent to Ti corners. For both adspecies, we also observe several complex adatom/island interactions, before and after descent onto the terrace, including two instances of Ti island-atom ascent onto the island surface. - Highlights: • We use classical molecular dynamics to model Ti and N adatom migration on TiN(001) islands. • N adatoms remain on islands significantly longer than Ti adatoms. • Ti adatoms descend via push-out/exchange, N adatoms primarily by direct hops. • N adatoms act as precursors for multilayer formation and surface roughening

  2. Deposit of thin films of TiN, a-C, Ti/TiN/a-C by laser ablation

    International Nuclear Information System (INIS)

    Mejia, I.S.; Escobar A, L.; Camps, E.; Romero, S.; Muhl, S.

    2006-01-01

    Thin films of titanium nitride (TiN), amorphous carbon (a-C), as well as bilayers of Ti/TiN/a-C were deposited by means of the laser ablation technique. It was investigated the effect that it has the laser fluence used to ablation the targets in the structure and mechanical properties of the TiN deposited films. The TiN obtained films have a preferential orientation in the direction (200). The results show that the hardness of this material is influenced by the laser fluence. It is observed that the hardness is increased in an approximately lineal way with the increment of the fluence up to 19 J/cm 2 . The films of amorphous carbon present hardness of the order of 11.2 GPa. Likewise it was found that the multilayers of Ti/TiN/aC presented a bigger hardness that of its individual components. (Author)

  3. The permeation behavior of deuterium through 1Cr18Ni9Ti stainless steel with TiN+TiC-TiN multiple films

    International Nuclear Information System (INIS)

    Xiong, Y.; Song, J.; Luo, D.; Lei, Q.; Chen, C.

    2015-01-01

    The prevention of tritium losses via permeation through structure components is an important issue in fusion technology. The production of thin layers on materials with low diffusivity and/or low surface recombination constants (so-called permeation barriers) seems to be the most practical method to reduce or hinder the permeation of tritium through materials. TiN+TiC+TiN multiple films are deposited on the surface of 1Cr18Ni9Ti stainless steel by ion-beam assisted deposition technology. The characteristics of films are tested by XPS ASEM and XRD, which shows that the film are compact and uniform with a thickness of about 15 μm, and have a good adherence with the substrate below 773 K. The diffraction peaks in the XRD patterns for TiC and TiN are broadened, implying that the multiple films are deposited on the surface of 1Cr18Ni9Ti stainless steel. Meanwhile, the C-H bonded CH 4 -appears in the infrared spectra of multiple films, suggesting that the CH 4 - is in a static state, so hydrogen atom cannot migrate from the site bonded with carbon to a neighboring site. The measured deuterium permeability in 1Cr18Ni9Ti stainless steel coated with multiple films is 2-3 orders of magnitude lower than that of pure 1Cr18Ni9Ti stainless steel substrate from 473 K to 773 K. However, this barrier is partly destroyed above 773 K

  4. Composition powders of the system TiC-TiB2

    International Nuclear Information System (INIS)

    Degrave, I.E.; Udalov, Yu.P.

    2000-01-01

    The ceramic composition on TiC-TiB 2 base is proposed for substitution of scarce and expensive tungsten carbide for manufacturing metallo-ceramic articles. The technology of TiC and TiB 2 powder production from the mixture of oxides and carbon-bearing reducing agents is developed. Saccharose is recommended to be used as a reductant. Carbon tetrachloride vapors are introduced into the reaction volume to accelerate the synthesis. The purification of the product from residual carbon is performed in high frequency glow discharge with the use of air as a plasma forming gas. Microstructural studies show that the product obtained constitutes submicron TiC particles in a TiB 2 matrix [ru

  5. Deformation twinning in metals and ordered intermetallics-Ti and Ti-aluminides

    Science.gov (United States)

    Yoo, M. H.; Fu, C. L.; Lee, J. K.

    1991-06-01

    The role of deformation twinning in the strength and ductility of metals and ordered intermetallic alloys is examined on the basis of crystallography, energetics and kinetics of deformation twinning. A systematic analysis is made by taking Ti, Ti3AI, TiAl, and A13Ti as four model systems. In comparison with profuse twinning in Ti, the intrinsic difficulty of twinning in Ti3A1 is rationalized in terms of the interchange shuffling mechanism. A fault (SISF) dragging mechanism based on the interaction torque explains the physical source for the low mobility of screw superdislocations in TiAl, which may lead to (111) [ 11bar{2}] twin nucleation. In TiAl and A13Ti alloys, the twin-slip (ordinary) conjugate relationship makes an important contribution to the strain compatibility for high-temperature plasticity. Potentially beneficial alloying additions to promote twinning are discussed. Les conséquences de la déformation par maclage sur la fracture et la ductilité des métaux et alliages intermétalliques ordonnés sont étudiées en fonction de la cristallographie, de l'énergie et de la cinétique des déformations par maclage. Une analyse systématique a été faite en considérant Ti, Ti3AI, TiAl et A13Ti comme quatre systèmes modèles. En comparaison avec le nombre important de maclages observés dans Ti, la difficulté intrinsèque des maclages dans Ti3AI est rationalisée en terme de mécanisme d'“interchange shuffling”. Un mécanisme de “dragging fault” basé sur l'interaction “torque” explique l'origine physique de la faible mobilité des superdislocations vissées dans TiAl qui peuvent conduire à la nucléation des macles (111) 112. Dans les alliages tels TiAl et A13Ti, la relation conjuguée entre la macle et le glissement (ordinaire) contribue de façon importante à la compatibilité des contraintes lors de la déformation plastique à haute température. Des effets bénéfiques potentiels liés à des éléments d'addition sur le processus

  6. Formation of Ti(III) and Ti(IV) states in Ti{sub 3}O{sub 5} nano- and microfibers obtained from hydrothermal annealing of C-doped TiO{sub 2} on Si

    Energy Technology Data Exchange (ETDEWEB)

    Stem, Nair, E-mail: nairstem@hotmail.com [Laboratório de Sistemas Integráveis (LSI), Escola Politécnica, Universidade de São Paulo, Av. Prof. Luciano Gualberto 158, 05508900 São Paulo, SP (Brazil); Souza, Michele L.; Araújo de Faria, Dalva Lúcia Araújo [Laboratório de Espectroscopia Molecular (LEM), Instituto de Química, Universidade de São Paulo, Av. Prof. Lineu Prestes 748, 05508900 São Paulo, SP (Brazil); Santos Filho, Sebastião G. dos [Laboratório de Sistemas Integráveis (LSI), Escola Politécnica, Universidade de São Paulo, Av. Prof. Luciano Gualberto 158, 05508900 São Paulo, SP (Brazil)

    2014-05-02

    In this work, it is investigated the formation of Ti(III) and Ti(IV) states at the surface and in the bulk of the Ti{sub 3}O{sub 5} material grown as meshes of nano- and micro-fibers obtained from hydrothermal annealing of C-doped TiO{sub 2} on Si. The topography and distribution of the fibers in the meshes were characterized by atomic force microscopy. When the fiber distribution was more compact, a higher photoluminescence signal at 850 nm (1.46 eV) was obtained, indicating the presence of a higher number of defects corresponding to the Ti(III) sites. From X-ray photoelectron spectroscopy, it was obtained a Ti(III)/Ti(IV) ratio much lower than the expected value for the Ti{sub 3}O{sub 5} phase (2 Ti(III): 1 Ti(IV)). The discrepancy was mainly attributed to the reaction of surface Ti(III) states of the Ti{sub 3}O{sub 5} fibers with water during the hydrothermal annealing, resulting in surface Ti(IV) with -OH radicals. On the other hand, X-ray photoelectron spectroscopy also indicated that substitutional and interstitial carbon atoms coexist, elemental carbon exists in the samples due to the co-deposition process and, as a result, the carbon inside of the TiO{sub 2} rutile lattice is acting as one of the precursors for the formation of Ti{sub 3}O{sub 5}. - Highlights: • Ti(III) states are detected inside of Ti{sub 3}O{sub 5} nano- and microfibers. • Ti(IV) states are predominantly detected on the surface of Ti{sub 3}O{sub 5} nano- and microfibers. • Photoluminescence at 850 nm for Ti{sub 3}O{sub 5} is due to defects associated to Ti(III). • Rutile possibly changes to C2/m Ti{sub 3}O{sub 5} during the hydrothermal annealing of C-doped TiO{sub 2}.

  7. Characterization of laser deposited Ti6Al4V/TiC composite powders on a Ti6Al4V substrate

    CSIR Research Space (South Africa)

    Mahamood, RM

    2014-01-01

    Full Text Available This paper reports the material characterization of Ti6Al4V/TiC composite produced by laser metal deposition. The Ti6Al4V/TiC composites were deposited with a composition ratio of 50 wt.% Ti64l4V and 50 wt.% TiC. The depositions were achieved...

  8. Layered Composite of TiC-TiB2 to Ti-6Al-4V in Graded Composition by Combustion Synthesis in High-gravity Field

    International Nuclear Information System (INIS)

    Huang Xuegang; Zhao Zhongmin; Zhang Long

    2013-01-01

    By taking combustion synthesis to prepare solidified TiB 2 matrix ceramic in high-gravity field, the layered composite of TiC-TiB 2 ceramic to Ti-6Al-4V substrate in graded composition was achieved. XRD, FESEM and EDS results showed that the bulk full-density solidified TiC-TiB 2 composite was composed of fine TiB 2 platelets, TiC irregular grains, a few of α-Al 2 O 3 inclusions and Cr alloy phases, and α'-Ti phases alternating with Ti-enriched carbides constituted the matrix of the joint in which fine TiB platelets were embedded, whereas some C, B atoms were also detected at the heat-affected zone of Ti-6A1-4V substrate. The layered composite of the solidified ceramic to Ti-6Al-4V substrate in graded composition with continuous microstructure was considered a result of fused joint and inter-diffusion between liquid ceramic and surface-molten Ti alloy, followed by TiB 2 -Ti peritectic reaction and subsequent eutectic reaction in TiC-TiB-Ti ternary system.

  9. Contribution to the study of U-Ti and U-Pu-Ti carbides; Contribution a l'etude des carbures U-C-Ti et (U, Pu) - C-Ti

    Energy Technology Data Exchange (ETDEWEB)

    Milet, C A [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1968-07-01

    After having discussed the reasons to use (U,Pu) carbides as fast reactor fuel, we examine the influence of the addition of titanium to these carbides. A preliminary study has been done on the system of U-C-Ti and some properties have been measured such as: density, thermal expansion, electrical resistivity, atmospheric corrosion and compatibility with stainless steel. The systems U-Pu-C-Ti (Pu/U + Pu equal to 15 per cent) and U-C-Ti have been found to be very similar. There exists a two phases region (U,Pu)C + TiC, an eutectic between (U,Pu)C and TiC for approximately 15 at %. The solubilities of U + Pu in TiC and of Ti in (U,Pu)C is less than 1 % at. The addition of titanium does not markedly change thermal expansion coefficients of (U,Pu)C. However the resistance to atmospheric corrosion and compatibility with stainless steel is improved. Thermal conductivity, calculated from electrical resistivity, has increased. On the other side, the density of fissile material is lowered. The combination of (U,Pu)C + TiC seems to be the most promising alloy for application as nuclear fuel. (author) [French] Apres avoir rappele les problemes poses par un combustible pour les reacteurs a neutrons rapides et l'interet des carbures U-Pu-C comme combustible, on examine l'influence de l'addition de titane dans ces carbures. Une etude preliminaire sur le systeme U-C-Ti a ete effectuee et quelques proprietes sont indiquees: densite, coefficients de dilatation, resistivite electrique, tenue a la corrosion atmospherique, compatibilite avec l'acier inoxydable. Le systeme U-Pu-C-Ti (Pu/U + Pu egal a 15 pour cent) presente de grandes analogies avec le systeme U-C-Ti. Il existe un domaine biphase (U,Pu)C + TiC, un eutectique entre (U,Pu)C et TiC pour environ 15 at % Ti; les solubilites de U + Pu clans TiC et de Ti dans (U,Pu)C sont inferieures a 1 at %. Par rapport a la phase (U,Pu)C, l'addition de titane est sans effets importants sur les coefficients de dilatation. Par contre la tenue a

  10. Characterization and Comparison of Photocatalytic Activity Silver Ion doped on TiO2(TiO2/Ag+) and Silver Ion doped on Black TiO2(Black TiO2/Ag+)

    Science.gov (United States)

    Kim, Jin Yi; Sim, Ho Hyung; Song, Sinae; Noh, Yeoung Ah; Lee, Hong Woon; Taik Kim, Hee

    2018-03-01

    Titanium dioxide (TiO2) is one of the representative ceramic materials containing photocatalyst, optic and antibacterial activity. The hydroxyl radical in TiO2 applies to the intensive oxidizing agent, hence TiO2 is suitable to use photocatalytic materials. Black TiO2was prepared through reduction of amorphous TiO2 conducting under H2 which leads to color changes. Its black color is proven that absorbs 100% light across the whole-visible light, drawing enhancement of photocatalytic property. In this study, we aimed to compare the photocatalytic activity of silver ion doped on TiO2(TiO2/Ag+) and silver ion doped on black TiO2(black TiO2/Ag+) under visible light range. TiO2/Ag+ was fabricated following steps. 1) TiO2 was synthesized by a sol-gel method from Titanium tetraisopropoxide (TTIP). 2) Then AgNO3 was added during an aging process step for silver ion doping on the surface of TiO2. Moreover, Black TiO2/Ag+ was obtained same as TiO2/Ag+ except for calcination under H2. The samples were characterized X-ray diffraction (XRD), UV-visible reflectance (UV-vis DRS), and Methylene Blue degradation test. XRD analysis confirmed morphology of TiO2. The band gap of black TiO2/Ag+ was confirmed (2.6 eV) through UV-vis DRS, which was lower than TiO2/Ag+ (2.9 eV). The photocatalytic effect was conducted by methylene blue degradation test. It demonstrated that black TiO2/Ag+ had a photocatalytic effect under UV light also visible light.

  11. Strengthening mechanisms in Ti-6Al-4V/TiC composites

    International Nuclear Information System (INIS)

    Johnson, A.J. Wagoner; Kumar, K.S.; Briant, C.L.

    2004-01-01

    In this study, the compressive behavior of Ti-6Al-4V/TiC composites considered for ballistic applications was examined at strain rates of 0.1, 1.0, and 10 s-1. As little as 1 vol% of particulate TiC provided nearly a 25% increase in strength in Ti-6Al-4V/TiC composites over that of the monolithic Ti-6Al-4V, while subsequent additions of TiC did not provide proportional benefit. The mechanisms responsible for such a significant increase in strength were investigated for the first time in this study. Microscopy (optical, SEM, TEM) aided in identifying the possible strengthening mechanisms that are typically important to the strength of metal matrix composites. These mechanisms include grain size and subgrain size refinement and an increase in dislocation density, all of which can occur during processing. Two other important mechanisms are thermal mismatch strains and load transfer from the matrix to the particle; the contribution of these mechanisms to the strength of the composite was evaluated using the Eshelby approach. A quantitative comparison of the mechanisms listed clearly showed that none of them was responsible for the large increase in strength with only 1vol%TiC in Ti-6Al-4V. The results from this study show for the first time that carbon in solution is, by far, the most potent strengthening mechanism in the Ti-6Al-4V/TiC particulate composites

  12. XPS investigations of tribolayers formed on TiN and (Ti,Re)N coatings

    Energy Technology Data Exchange (ETDEWEB)

    Oktay, Serkan; Kahraman, Zafer; Urgen, Mustafa; Kazmanli, Kursat, E-mail: kursat@itu.edu.tr

    2015-02-15

    Graphical abstract: - Highlights: • The (Ti,Re)N coating (8 ± 1.9 at.% Re) consisted of TiN and ReNx (x > 1.33) phases. • TiO{sub 2} provided low friction coefficient to TiN coating at 150 °C. • Re addition to TiN drastically dropped the friction coefficients to 0.17–0.22. • Re{sub 2}O{sub 7} provided very low friction coefficient to (Ti,Re)N coating. • Re addition to TiN improved the wear behavior. - Abstract: TiN and (Ti,Re)N coatings were deposited on high-speed-steel substrates by a hybrid coating system composed of cathodic arc PVD and magnetron sputtering techniques. In order to keep rhenium content low (8 ± 1.9 at.%) in the coating, magnetron sputtering technique was utilized to evaporate rhenium. The (Ti,Re)N coating consisted of TiN and ReN{sub x} (x > 1.33) phases. The hardness of TiN and (Ti,Re)N were 31 GPa and 29 GPa ( ± 2 GPa), respectively. Tribological behaviors of the samples were tested against Al{sub 2}O{sub 3} balls at 21 °C (RT) and 150 °C (HT) by reciprocating wear technique. The tribolayers were analyzed by XPS technique. Friction coefficients of TiN were 0.56, 0.35 for 21 °C and 150 °C tests, respectively. Rhenium addition to TiN drastically dropped the friction coefficients to 0.22 and 0.17 for RT and HT samples. Rhenium addition also improved the wear resistance of the coating at both test temperatures. For TiN, main oxide component of the tribolayers was Ti{sub 2}O{sub 3} for RT tests and TiO{sub 2} for HT tests. The oxide layer formed on (Ti,Re)N were the mixture of TiO{sub 2}, Ti−O−N, ReO{sub 2} and Re{sub 2}O{sub 7} for both test temperatures. Re{sub 2}O{sub 7} provided very low friction coefficient to (Ti,Re)N. The findings are consistent with the crystal chemistry approach.

  13. Biomineralisation with Saos-2 bone cells on TiSiN sputtered Ti alloys.

    Science.gov (United States)

    V V, Anusha Thampi; Bendavid, Avi; Martin, P J; Vaithilingam, Vijay; Bean, Penelope A; Evans, Margaret D M; Subramanian, B

    2017-07-01

    Surface modifications of metallic implants are important in order to protect the underlying metals from the harsh corrosive environment inside the human body and to minimize the losses caused by wear. Recently, researches are carried out in developing bioactive surfaces on metallic implants, which supports the growth and proliferation of cells on to these surfaces. Titanium silicon nitride (TiSiN) hard nanocomposites thin films were fabricated on Ti alloys (Ti-6Al-4V) by pulsed direct current (DC) reactive magnetron sputtering. The films were characterized for its microstructural and electrochemical behavior. The higher charge transfer resistance (Rct) and positive shift in Ecorr value of TiSiN/Ti alloys than the bare Ti-alloys indicates a better corrosion resistance offered by the TiSiN thin films to the underlying substrates. The biological response to TiSiN/Ti alloys and control bare Ti-alloys was measured in vitro using cell-based assays with two main outcomes. Firstly, neither the Ti alloy nor the TiSiN thin film was cytotoxic to cells. Secondly, the TiSiN thin film promoted differentiation of human bone cells above the bare control Ti alloy as measured by alkaline phosphatase and calcium production. TiSiN thin films provide better corrosion resistance and protect the underlying metal from the corrosive environment. The thin film surface is both biocompatible and bioactive as indicated from the cytotoxicity and biomineralization studies. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Effect of TiH2 in the preparation of MMC Ti based with TiC reinforcement

    International Nuclear Information System (INIS)

    Peillon, N.; Fruhauf, J.B.; Gourdet, S.; Feraille, J.; Saunier, S.; Desrayaud, C.

    2015-01-01

    Highlights: • Using TiH 2 precursors promotes the MMC densification and microstructure homogeneity. • Clear description of the TiH 2 interest and limitations. • Coupling of TGA, TMA and EBSD analyses to investigate the sintering process of MMC. • Process parameters: granulometry, precursor composition, temperature and rate. - Abstract: Many studies were carried out on the elaboration Metal Matrix Composites (MMCs) and a wide variety of process is reported in the bibliography. For titanium based MMC, the basis material for these elaboration techniques mainly consists of atomized titanium powder. In this work a titanium hydride powder is used to elaborate Ti/TiC MMC. Although an additional dehydrogenation operation is required a significant decrease of the sintering temperature is expected with this basis powder. In this context, the behavior of titanium hydride powder mixed with 0, 10 and 20 vol.% TiC reinforcement is studied during densification by free sintering. The effects of particle size, temperature and rate of sintering reinforcement are discussed. The comparison of the TiH 2 process with Ti HDH (Hydride Dehydride) and atomized Ti mixture is made with 10 vol.% reinforcement. The results indicate that the sintering temperature is lowered and the final densities achieved are higher if the hydride is used. Interactions between dehydrogenation and sintering mechanisms clearly appear for the higher sintering temperature rate (10 °C/min) and need specific attention to prevent porosity nucleation through hydrogen entrapment

  15. Synthesis, Characterization, and NIR Reflectance of Highly Dispersed NiTiO3 and NiTiO3/TiO2 Composite Pigments

    Directory of Open Access Journals (Sweden)

    Yuping Tong

    2016-01-01

    Full Text Available The highly dispersed nanostructured NiTiO3 pigments and NiTiO3/TiO2 composite pigments can be synthesized at relative low temperature. The activation energy of crystal growth of NiTiO3 during calcinations via salt-assistant combustion method is 9.35 kJ/mol. The UV-vis spectra results revealed that the absorbance decreased with the increasing of calcinations temperature due to small size effect of nanometer particles. The optical data of NiTiO3 nanocrystals were analyzed at the near-absorption edge. SEM showed that the obtained NiTiO3 nanocrystals and NiTiO3/TiO2 nanocomposite were composed of highly dispersed spherical-like and spherical particles with uniform size distribution, respectively. The chromatic properties and diffuse reflectance of samples were investigated. The obtained NiTiO3/TiO2 composite samples have higher NIR reflectance than NiTiO3 pigments.

  16. Characterisation and behaviour of Ti/TiO2/noble metal anodes

    International Nuclear Information System (INIS)

    Gueneau de Mussy, Jean-Paul; Macpherson, Julie V.; Delplancke, Jean-Luc

    2003-01-01

    The morphology, composition and the electrical and electrochemical behaviour of the anodic microporous layer, prepared by the galvanostatic anodisation of Ti after sparking, followed by galvanostatic deposition of Pt or Ir have been investigated. These electrodes are proposed to function as dimensionally stable anodes (DSAs). For Ti/TiO 2 /Pt electrodes, Pt is deposited within some of the micropores of the oxide film. In contrast, for Ti/TiO 2 /Ir, the metal is deposited preferentially on the top surface. This difference is thought to result from the position of the metal deposition potential with respect to the flat band potential of n-TiO 2 . Optical imaging of both types of DSA suggests that only a few sites on the surface are responsible for electron exchange at the DSA-electrolyte interface. C-AFM measurements of Ti/TiO 2 /Pt samples subjected to long-term anodic polarisation, suggest that the Ti-noble metal contact is progressively insulated by thickening of the TiO 2 barrier layer, promoting passivation of the DSA. For Ir coated anodes, catalytic activity is directly related to the presence of Ir and to the stability of the catalytic oxide layer. Under Cu electrowinning conditions, the electrochemically formed hydrated Ir oxide was found to be catalytically less stable, than the iridium oxide film subjected to a heat treatment

  17. Microstructure and refinement performance of Al-Ti-C master alloy: Effect of excess Ti on the growth and nucleating ability of TiC particles

    Science.gov (United States)

    Svynarenko, Kateryna; Zhang, Yubo; Jie, Jinchuan; Kutsova, Valentyna; Li, Tingju

    2017-09-01

    Al-5Ti-0.2C, Al-0.8Ti-0.2C, Al-8Ti-2C, and Al-10Ti master alloys were prepared and used to investigate the influence of excess Ti on the growth of TiC particles and its ability to nucleate Al-grains. The results of a microstructure analysis of TiC-containing alloys and refined CPAl were interrelated to the results of a refinement test. It was found that the presence of excess Ti is essential at the stage of master alloy preparation, as it facilitates the growth and uniform distribution of TiC within the structure. In Al-5Ti-0.2C alloy containing excess Ti, carbide particles grow faster and to a higher extent (from 0.29 μm to 0.44 μm) compared to Al-0.8Ti-0.2C alloy produced without excess Ti (from 0.29 μm to 0.32 μm). The results support the "Ti-transition zone theory" as the mechanism of grain refinement by TiC-containing master alloys. The refinement performance of Al-5Ti-0.2C is superior compared to the one achieved by adding Al-8Ti-2C and Al-10Ti master alloys in corresponding concentrations. For the TiC particles to become favourable nucleating sites, they must undergo certain interaction with excess Ti at the stage of master alloy preparation.

  18. Controllable hydrothermal synthesis of rutile TiO{sub 2} hollow nanorod arrays on TiCl{sub 4} pretreated Ti foil for DSSC application

    Energy Technology Data Exchange (ETDEWEB)

    Xi, Min [Key Laboratory of Renewable Energy, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640 (China); Zhang, Yulan; Long, Lizhen [Key Laboratory of Renewable Energy, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Li, Xinjun, E-mail: lixj@ms.giec.ac.cn [Key Laboratory of Renewable Energy, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640 (China)

    2014-11-15

    Rutile TiO{sub 2} nanorod arrays (TNRs) were achieved by hydrothermal process on TiCl{sub 4} pretreated Ti foil. Subsequently, TNRs were hydrothermally etched in HCl solution to form hollow TiO{sub 2} nanorod arrays (H-TNRs). The TiCl{sub 4} pretreatment plays key roles in enhancement of Ti foil corrosion resistance ability and crystal nucleation introduction for TNRs growth. TNRs with desired morphology can be obtained by controlling TiCl{sub 4} concentration and the amount of tetrabutyl titanate (TTB) accordingly. TNRs with the length of ∼1.5 μm and diameter of ∼200 nm, obtained on 0.15 M TiCl{sub 4} pretreated Ti foil with 0.6 mL TTB, exhibits relatively higher photocurrent. The increased pore volume of the H-TNRs has contributed to the increased surface area which is benefit for Dye-Sensitized Solar Cells (DSSC) application. And the 180 °C-H-TNRs photoanode obtained from the 0.15-TiCl{sub 4}-TNRs sample demonstrated 128.9% enhancement of photoelectric efficiency of DSSC compared to that of the original TNR photoanode. - Graphical abstract: Rutile hollow TiO{sub 2} nanorod array photoanode obtained from original TiO{sub 2} nanorod array photoanode by hydrothermal etching demonstrates enhanced photoelectric efficiency of DSSC. - Highlights: • TiO{sub 2} nanorods are prepared via hydrothermal process on TiCl{sub 4}-pretreated Ti foil. • Hollow TiO{sub 2} nanorods are obtained by hydrothermal etching of TiO{sub 2} nanorods. • TiCl{sub 4} pretreatment plays a key role in protecting Ti foil from chemical corrosion. • Hollow TiO{sub 2} nanorods photoanode shows enhanced photoelectric efficiency for DSSC.

  19. Laser processing of in situ TiN/Ti composite coating on titanium.

    Science.gov (United States)

    Sahasrabudhe, Himanshu; Soderlind, Julie; Bandyopadhyay, Amit

    2016-01-01

    Laser remelting of commercially pure titanium (CP-Ti) surface was done in a nitrogen rich inert atmosphere to form in situ TiN/Ti composite coating. Laser surface remelting was performed at two different laser powers of 425 W and 475 W. At each power, samples were fabricated with one or two laser scans. The resultant material was a nitride rich in situ coating that was created on the surface. The cross sections revealed a graded microstructure. There was presence of nitride rich dendrites dispersed in α-Ti matrix at the uppermost region. The structure gradually changed with lesser dendrites and more heat affected α-Ti phase maintaining a smooth interface. With increasing laser power, the dendrites appeared to be larger in size. Samples with two laser scans showed discontinuous dendrites and more α-Ti phase as compared to the samples with one laser scan. The resultant composite of TiN along with Ti2N in α-Ti showed substantially higher hardness and wear resistance than the untreated CP-Ti substrate. Coefficient of friction was also found to reduce due to surface nitridation. Leaching of Ti(4+) ions during wear test in DI water medium was found to reduce due to laser surface nitriding. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. XPS study on the electronic structure of hydrided Ti-V, Ti-Nb and Ti-Mo alloys

    International Nuclear Information System (INIS)

    Tanaka, Kazuhide; Aoki, Hiromasa

    1989-01-01

    Effects of hydrogenation on the core and valence electronic structures of β(bcc)-stabilized Ti-25at%V, Ti-50at%Nb and Ti-20at%Mo alloys are studied with XPS technique using monochromatized Al K α radiation. Small but uniform binding-energy shifts are observed upon hydrogenation for all the core spectra measured. Their valence-band spectra are significantly distorted, providing an evidence of the formation of metal-hydrogen bonding bands in these Ti alloys. Interrelations between the core binding-energy shifts and the valence-band distortion are discussed. (orig.)

  1. Deformation mechanisms in Ti/TiN multilayer under compressive loading

    International Nuclear Information System (INIS)

    Yang, Wei; Ayoub, Georges; Salehinia, Iman; Mansoor, Bilal; Zbib, Hussein

    2017-01-01

    The promising mechanical, physical and chemical properties of nano-scale metal/ceramic multilayers (MCMs) are of high interest for extreme environment applications. Understanding the plastic deformation mechanisms and the variables affecting those properties is therefore essential. The interface characteristics and the plastic deformation mechanisms under compressive loading in a Ti/TiN multilayer with a semi-coherent interface are numerically investigated. The interface structure of the Ti/TiN interface and the interface misfit dislocation were characterized using molecular dynamic simulations combined with atomically informed Frank-Bilby method. Three possible atomic stacking interface structures are identified according to the crystallographic analysis of the interface. Upon relaxation, large interface areas are occupied with the energetically stable configuration. Furthermore, the higher energy stacking are transformed into misfit dislocations or dislocation nodes. The molecular dynamic compressive stress strain response of the Ti/TiN multilayers exhibited three distinctive peaks. The first peak was generated by the dislocation dissociation of perfect dislocation into pairs of partials dislocation around extended nodes region at the interface. Upon further compression the second peak, identified as the first yielding, resulted from the activation of pyramidal slip planes in the Ti layer. Finally, a third peak identified as the second yielding, occurred when dislocation nucleated/transmitted in/into the TiN layer.

  2. AlTiN layer effect on mechanical properties of Ti-doped diamond-like carbon composite coatings

    International Nuclear Information System (INIS)

    Pang Xiaolu; Yang Huisheng; Gao Kewei; Wang Yanbin; Volinsky, Alex A.

    2011-01-01

    Ti/Ti-doped diamond-like carbon (DLC) and Ti/AlTiN/Ti-DLC composite coatings were deposited by magnetron sputtering on W18Cr4V high speed steel substrates. The effect of the AlTiN support layer on the properties of these composite coatings was investigated through microstructure and mechanical properties characterization, including hardness, elastic modulus, coefficient of friction and wear properties measured by scanning electron microscopy, Raman spectroscopy, scratch and ball-on-disk friction tests. Ti and AlTiN interlayers have a columnar structure with 50-80 nm grains. The hardness and elastic modulus of Ti/Ti-DLC and Ti/AlTiN/Ti-DLC coatings is 25.9 ± 0.4, 222.2 ± 6.3 GPa and 19.3 ± 1, 205.6 ± 6.7 GPa, respectively. Adhesion of Ti-DLC, Ti/AlTiN/Ti-DLC and AlTiN/Ti-DLC coatings expressed as the critical lateral force is 26.5 N, 38.2 N, and 47.8 N, respectively. Substrate coefficient of friction without coatings is 0.44, and it is 0.1 for Ti/Ti-DLC and Ti/AlTiN/Ti-DLC coatings. Wear resistance of Ti/AlTiN/Ti-DLC composite coatings is much higher than Ti/Ti-DLC coatings based on the wear track width of 169.8 and 73.2 μm, respectively, for the same experimental conditions.

  3. Structural comparison of sintering products made of "TiC + Ti" composite powders and "Ti + C" powder mixtures

    Science.gov (United States)

    Krinitcyn, Maksim G.; Pribytkov, Gennadii A.; Korosteleva, Elena N.; Firsina, Irina A.; Baranovskii, Anton V.

    2017-12-01

    In this study, powder composite materials comprised of TiC and Ti with different ratios are processed by sintering of Ti and C powder mixtures and self-propagating high-temperature synthesis (SHS) in "Ti+C" system followed by sintering. The microstructure and porosity of obtained composites are investigated and discussed. The dependence of porosity on sintering time is explained theoretically. Optimal regimes that enable to obtain the most homogeneous structure with the least porosity are described.

  4. Microstructure and mechanical properties of Ti/TiN film coated on AISI 304 stainless steel

    International Nuclear Information System (INIS)

    Park, Ji Yoon; Kim, Kwan Hyu; Choe, Han Cheol

    1999-01-01

    The microstructure and mechanical properties of Ti/TiN film coated on AISI 304 stainless steels have been studied. AISI 304 stainless steels containing 0.1∼1.0 wt% Ti were fabricated by using vacuum furnace and followed by solutionization treatment at 1050 .deg. C for 1hr. The specimens were coated by Ti and TiN with 1 μm and 2 μm thickness by electron-beam PVD method. The microstructure and phase analysis were carried out by using XRD, WDS and SEM. Mechanical properties such as hardness (micro-Vickers) and wear resistance were examined. Coated films showed fine columnar structure and some defects. Surface roughness increased in all specimens after TiN coating. XRD patterns showed that the TiN(111) peak was major in TiN single-layer and the other peaks were very weak, but TiN(220) and TiN(200) peaks were developed in Ti/TiN double-layer. The hardness of the coating film was higher in Ti/TiN double-layer than in TiN single-layer and not affected by the Ti content of substrate. Ti/TiN double-layer showed better wear resistance than TiN single-layer. The observed wear traces were sheared type in all coated specimens

  5. Electrochemical properties of Ti3+ doped Ag-Ti nanotube arrays coated with hydroxyapatite

    Science.gov (United States)

    Zhang, Hangzhou; Shi, Xiaoguo; Tian, Ang; Wang, Li; Liu, Chuangwei

    2018-04-01

    Ag-Ti nanotube array was prepared by simple anodic oxidation method and uniform hydroxyapatite were electrochemically deposited on the nanotubes, and then characterized by SEM, XRD, XPS and EIS. In order to investigate the influence of Ti3+ on the electrochemical deposition of hydroxyapatite on the nanotubes, the Ag-Ti nanotube array self-doped with Ti3+ was prepared by one step reduction method. The experiment results revealed that the Ti3+ can promote the grow rate of hydroxyapatite coatings on nanotube surface. The hydroxyapatite coated Ag-Ti nanotube arrays with Ti3+ exhibit excellent stability and higher corrosion resistance. Moreover, the compact and dense hydroxyapatite coating can also prevent the Ag atom erosion from the Ag-Ti nanotube.

  6. Characteristics and in vitro biological assessment of (Ti, O, N)/Ti composite coating formed on NiTi shape memory alloy

    International Nuclear Information System (INIS)

    Sun Tao; Wang Langping; Wang Min; Tong, Ho-Wang; Lu, William W.

    2011-01-01

    In this investigation, plasma immersion ion implantation and deposition (PIIID) was used to fabricate a (Ti, O, N)/Ti coating on NiTi shape memory alloy (SMA) to improve its long-term biocompatibility and wear resistance. The surface morphology, composition and roughness of uncoated and coated NiTi SMA samples were examined. Energy dispersive X-ray elemental mapping of cross-sections of (Ti, O, N)/Ti coated NiTi SMA revealed that Ni was depleted from the surface of coated samples. No Ni was detected by X-ray photoelectron spectroscopy on the surface of coated samples. Furthermore, three-point bending tests showed that the composite coating could undergo large deformation without cracking or delamination. After 1 day cell culture, SaOS-2 cells on coated samples spread better than those on uncoated NiTi SMA samples. The proliferation of SaOS-2 cells on coated samples was significantly higher at day 3 and day 7 of cell culture.

  7. Optical and structural properties of TiO2/Ti/Ag/TiO2 and TiO2/ITO/Ag/ITO/TiO2 metal-dielectric multilayers by RF magnetron sputtering for display application

    International Nuclear Information System (INIS)

    Lee, Jang-Hoon; Lee, Seung-Hyu; Hwangbo, Chang-Kwon; Lee, Kwang-Su

    2004-01-01

    Electromagnetic-interference (EMI) shielding and near-infrared (NIR) cutoff filters for plasma display panels, based on fundamental structures (ITO/Ag/ITO), (TiO 2 /Ti/Ag/TiO 2 ) and (TiO 2 /ITO/Ag/ITO/TiO 2 ), were designed and prepared by RF-magnetron sputtering. The optical, structural and electrical properties of the filters were investigated by using spectrophotometry, Auger electron spectroscopy, X-ray photoelectron spectroscopy, Rutherford backscattering spectroscopy, atomic force microscopy and four-point-probe measurements. The results show that ITO films as the barriers and base layers lead to higher transmittance in the visible spectrum and smoother surface roughness than Ti metal barriers, while maintaining high NIR cutoff characteristics and chemical stability, which may be attributed to the lower absorption in the interfacial layers and better protection of the Ag layers by the ITO layers.

  8. Study and characterization of the irreversible transformation of electrically stressed planar Ti/TiO{sub x}/Ti junctions

    Energy Technology Data Exchange (ETDEWEB)

    Guillaume, N.; Puyoo, E., E-mail: etienne.puyoo@insa-lyon.fr; Le Berre, M.; Albertini, D.; Baboux, N.; Chevalier, C.; Ayadi, K.; Grégoire, J.; Gautier, B.; Calmon, F. [Institut des Nanotechnologies de Lyon, Université de Lyon, INL UMR 5270, CNRS, INSA de Lyon, Villeurbanne F-69621 (France)

    2015-10-14

    We investigate the properties and characteristics of planar Ti/TiO{sub x}/Ti junctions, which consist of transverse TiO{sub x} lines drawn on Ti test patterns. Junctions are elaborated by means of local anodic oxidation using atomic force microscopy. An irreversible morphological transformation occurring in a reproducible manner is observed when these planar junctions are electrically stressed under ambient atmosphere. Structural and chemical analyses based on transmission electron microscopy techniques reveal the extension of the initial amorphous TiO{sub x} into a crystalline rutile phase. This irreversible transformation is proven to vanish completely if the electrical stress occurs under vacuum atmosphere. Finally, we carry out temperature dependent electrical measurements in order to elucidate their conduction mechanism: Schottky emission above an ultra-low potential barrier is assumed to dominate under vacuum atmosphere whereas ionic conduction seems to prevail in air.

  9. Fabrication of steel matrix composites locally reinforced with different ratios of TiC/TiB2 particulates using SHS reactions of Ni-Ti-B4C and Ni-Ti-B4C-C systems during casting

    International Nuclear Information System (INIS)

    Yang Yafeng; Wang Huiyuan; Liang Yunhong; Zhao Ruyi; Jiang Qichuan

    2007-01-01

    Steel matrix composites locally reinforced with different molar ratios of in situ TiC/TiB 2 particulates (2:1, 1:1 and 1:2, respectively) have been fabricated successfully utilizing the self-propagating high-temperature synthesis (SHS) reactions of Ni-Ti-B 4 C and Ni-Ti-B 4 C-C systems during casting. Differential thermal analysis (DTA) and X-ray diffraction (XRD) results reveal that the exothermic reactions of the Ni-Ti-B 4 C and Ni-Ti-B 4 C-C systems proceed in such a way that Ni initially reacts with B 4 C and Ti to form Ni 2 B and Ti 2 Ni compounds, respectively, with heat evolution at 1037 deg. C; Subsequently, the external heat and the evolved heat from these exothermic reactions promote the reactions forming TiC and TiB 2 at 1133 deg. C. In the composites reinforced with 1:2 molar ratio of TiC/TiB 2 , almost all TiB 2 grains have clubbed structures, while TiC grains exhibit near-spherical morphologies. Furthermore, TiB 2 grain sizes decrease, with the increase of TiC content. In particular, in the composites reinforced with 2:1 molar ratio of TiC/TiB 2 , it is difficult to find the clubbed TiB 2 grains. Macro-pores and blowholes are absent in the local reinforcing region of the composites reinforced with 1:1 and 1:2 molar ratios of TiC/TiB 2 , while a few macro-pores can be observed in the composite reinforced with 2:1 molar ratio of TiC/TiB 2 . Moreover, the densities of the composites reinforced with 1:1 and 1:2 molar ratios of TiC/TiB 2 are higher than that of the composite reinforced with 2:1 molar ratio of TiC/TiB 2 . The composite reinforced with 1:2 molar ratio of TiC/TiB 2 has the highest hardness and the best wear resistance

  10. Formation Mechanism of Spherical TiC in Ni-Ti-C System during Combustion Synthesis.

    Science.gov (United States)

    Zhu, Guoliang; Wang, Wei; Wang, Rui; Zhao, Chuanbao; Pan, Weitao; Huang, Haijun; Du, Dafan; Wang, Donghong; Shu, Da; Dong, Anping; Sun, Baode; Jiang, Sheng; Pu, Yilong

    2017-08-29

    The formation mechanism of TiC particles in a Ni-Ti-C system were revealed by using differential thermal analysis (DTA), XRD, and SEM to identify the reaction products in different temperature ranges. The results indicated that the synthesis mechanism of TiC in Ni-Ti-C system was complex; several reactions were involved in the combustion synthesis of TiC-Ni composite. The Ni-Ti intermediate phases play important roles during the formation of TiC. Moreover, the influence of heating rate on the size range of TiC was also discussed.

  11. Formation of hydroxyapatite on Ti-coated Ti-Zr-Cu-Pd bulk metallic glass

    International Nuclear Information System (INIS)

    Qin, F.X.; Wang, X.M.; Wada, T.; Xie, G.Q.; Asami, K.; Inoue, A.

    2009-01-01

    In this research, Ti coating was conducted on Ti 40 Zr 10 Cu 36 Pd 14 bulk metallic glass (BMG) in order to increase the formation rate of hydroxyapatite layer. The formation behavior of bone-like hydroxyapatite on Ti-coated and uncoated Ti 40 Zr 10 Cu 36 Pd 14 bulk metallic glasses (BMGs) was studied. The surface morphology of Ti-coated and uncoated Ti 40 Zr 10 Cu 36 Pd 14 BMG was investigated by scanning electron microscopy and energy dispersive X-ray spectroscopy. The results revealed that the alkali pretreatment in 5 M NaOH solution at 60degC for 24 h had a beneficial effect on the formation of porous sodium titanate on Ti-coated Ti 40 Zr 10 Cu 36 Pd 14 BMG. A bone-like hydroxyapatite layer was able to form on the alkali-treated Ti-coated Ti 40 Zr 10 Cu 36 Pd 14 BMG after a short-time immersion in simulated body fluid (SBF). On the contrary, hydroxyapatite formation was not observed on the uncoated Ti 40 Zr 10 Cu 36 Pd 14 BMG after the same chemical treatments. (author)

  12. Obtention of the TiFe compound by high-energy milling of Ti+Fe and TiH{sub 2}+Fe powder mixtures; Obtencao do composto TiFe a partir da moagem de alta energia de misturas Ti+Fe e TiH{sub 2}+Fe

    Energy Technology Data Exchange (ETDEWEB)

    Falcao, R.B.; Dammann, E.D.C.C.; Rocha, C.J.; Leal Neto, R.M., E-mail: railson.falcao@usp.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Ciencias e Tecnologia de Materiais. Lab. de Intermetalicos

    2010-07-01

    In this work TiFe compound was obtained by two process routes involving high-energy ball milling: mechanical alloying from Ti and Fe powders (route 1) and mechanical milling from TiH{sub 2} and Fe powders, both followed by an annealing heat treatment. Shaker and planetary ball mills were utilized for times varying from 1-25 hours. Milled and annealed powders were characterized by SEM and X-ray diffraction analyses. TiFe compound was formed in both routes. A strong powder adherence in the milling vial and balls occurred with route 1 in both mills. Powder adherence was significantly reduced by using TiH{sub 2} (route 2) mainly in the planetary mill, in spite of TiFe formation has only occurred after the annealing treatment. (author)

  13. Ultrasound assisted combustion synthesis of TiC in Al-Ti-C system.

    Science.gov (United States)

    Liu, Zhiwei; Rakita, Milan; Xu, Wilson; Wang, Xiaoming; Han, Qingyou

    2015-11-01

    This research investigated the effects of high-intensity ultrasound on the combustion synthesis of TiC particles in Al-Ti-C system. The process involved that high-intensity ultrasound was applied on the surface of a compacted Al-Ti-C pellet directly through a Nb probe during the thermal explosion reaction. By comparing with the sample without ultrasonic treatment, it was found that the thermal explosion reaction for synthesizing TiC phase could take place thoroughly in the ultrasonically treated sample. During the process of synthesizing TiC phase, the dissolution of solid graphite particles into the Al-Ti melt, as well as the nucleation and growth of TiC particles could be promoted effectively due to the effects of ultrasound, leading to an enhancement of the formation of TiC particles. Ultrasound assisted combustion synthesis as a simple and effective approach was proposed for synthesizing materials in this research. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Proton irradiation studies on pure Ti and Ti-6Al-4V

    Energy Technology Data Exchange (ETDEWEB)

    Dutta Gupta, A. [Variable Energy Cyclotron Centre, HBNI, 1/AF Bidhannagar, Kolkata (India); Mukherjee, P., E-mail: paramita@vecc.gov.in [Variable Energy Cyclotron Centre, HBNI, 1/AF Bidhannagar, Kolkata (India); Gayathri, N.; Bhattacharyya, P.; Bhattacharya, M. [Variable Energy Cyclotron Centre, HBNI, 1/AF Bidhannagar, Kolkata (India); Sarkar, Apu [Materials Group, Bhabha Atomic Research Centre, Mumbai (India); Sen, S. [Mechanical Engineering, Jadavpur University, Kolkata (India); Mitra, M.K. [Metallurgical and Materials Engineering, Jadavpur University, Kolkata (India)

    2016-11-15

    Post irradiated microstructural characterisation of pure Ti and Ti-6Al-4V has been done as a function of dose using different model based techniques of X-ray diffraction line profile analysis. There is a systematic change of domain size for both the materials with dose but the microstrain within the domain remains almost unaltered. The domain size appears to be lower for pure Ti at all doses as compared to Ti-6Al-4V alloy. XRD peaks became highly asymmetric particularly at a dose of 5 × 10{sup 21} p/m{sup 2} for Ti-6Al-4V samples which is not observed for pure Ti at the same dose. This may be attributed to the segregation of alloying elements as a result of irradiation. Microhardness values increases with dose for pure Ti and then saturates at higher doses whereas microhardness values are found to decrease at higher doses for Ti-6Al-4V.

  15. Study of TiC+TiN Multiple Films On Type of 316L Stainless Steel

    Institute of Scientific and Technical Information of China (English)

    XUE Qi; JIN Yong; HU Dong-ping; HUANG Ben-sheng; DENG Bai-quan

    2004-01-01

    In this paper, the synthesis process of TiC+TiN multiple films on super-low-carbon stainless steels is reported.The TiC layer is coated as the first layer in the multiple film, the change of growth rate of the film on the 316L Stainless steel is not same as the one on carbides substrates, while the mole ratio of CH4 to TiCl4 (mCH4/TiCl4) is changed from 1.2to 2.0. The Ti [C, N], as a kind of inter-layer between TiC and TiN layers, is helpful to improve the adhesion between the TiC and TiN layer. The cooling rate greatly influences the quality of the adhesion between the TiC+TiN film and substrates.

  16. Study of TiC+TiN Multiple Films On Type of 316L Stainless Steel

    Institute of Scientific and Technical Information of China (English)

    XUEQi; JINYong; HUDong-ping; HUANGBen-sheng; DENGBai-quan

    2004-01-01

    In this paper, the synthesis process of TiC+TiN multiple films on super-low-carbon stainless steels is reported. The TiC layer is coated as the first layer in the multiple film, the change of growth rate of the film on the 316L Stainlesss teel is not same as the one on carbides substrates, while the mole ratio of CH4 to TiCl4 (mCH4/TiCl4) is changed from 1.2 to 2.0. The Ti [C,N], as a kind of inter-layer between TiC and TiN layers, is helpful to improve the adhesion hetween the TiC and TiN layer. The cooling rate greatly influences the quality of the adhesion between the TiC+TiN film and substrates.

  17. Ti/TiO 2 nanotube array electrode as a new sensor to ...

    Indian Academy of Sciences (India)

    The Ti/TiO2 nanotube array (Ti-NTA) electrode was prepared by anodizing of the Ti foil ... and the pH=3.0 and =1.0 V (vs. reference electrode) were determined as the ... It was found that the photocurrent of EG was linearly dependent on the ...

  18. Stepwise Ti-Cl, Ti-CH3, and Ti-C6H5 bond dissociation enthalpies in bis(pentamethylcyclopentadienyl)titanium complexes

    NARCIS (Netherlands)

    Dias, Alberto R.; Salema, Margarida S.; Martinho Simões, Jose A.; Pattiasina, Johannes W.; Teuben, Jan H.

    1988-01-01

    Reaction-solution calorimetric studies involving the complexes Ti[η5-C5(CH3)5]2(CH3)2, Ti[η5-C5(CH3)5]2(CH3), Ti[η5-C5(CH3)5]2(C6H5), Ti[η5-C5(CH3)5]2Cl2, and Ti[η5-C5(CH3)5]2Cl, have enabled derivation of titanium-carbon and titanium-chlorine stepwise bond dissociation enthalpies in these species.

  19. 钛合金表面激光熔覆NiCrBSi(Ti)-TiC涂层%Study on laser cladding of NiCrBSi (Ti)-TiC metal-ceramiccomposite coatings on titanium alloy

    Institute of Scientific and Technical Information of China (English)

    孙荣禄; 郭立新; 董尚利; 杨德庄

    2001-01-01

    在TC4合金表面进行了激光熔覆NiCrBSi-TiC,Ti-TiC金属陶瓷复合涂层的试验,对涂层的组织和显微硬度进行了分析和测试.结果表明,NiCrBSi-TiC涂层的组织是在初晶γ-Ni和γ-Ni,Ni3B,M23(CB)6,CrB多元共晶的基底上均匀地分布着TiC颗粒,在激光熔覆过程中TiC颗粒只是边缘发生了溶解或熔化;在Ti-TiC涂层中,TiC颗粒全部溶解或熔化,冷却时以枝晶形式重新析出.NiCrBSi-TiC涂层的显微硬度(HV900~1100)明显高于Ti-TiC的涂层的显微硬度(HV500~700).

  20. Effect Of Ti Powder Addition On The Fabrication Of TiO2 Nanopowders

    Directory of Open Access Journals (Sweden)

    Raihanuzzaman R.M.

    2015-06-01

    Full Text Available Sintered samples of Ti added TiO2 nanopowders were fabricated by combined application of magnetic pulsed compaction (MPC and sintering. The effect of Ti nano powder on density, shrinkage and hardness of the samples were investigated as part of the study. The optimum processing conditions were found to be around 0.5 GPa MPC pressure and 1450°C sintering temperature, illustrating maximum density, hardness and minimum shrinkage. High pressure compaction using MPC was found to enhance density with increasing MPC pressure up to 0.9 GPa, and significantly reduce the total shrinkage (about 16% in this case in the sintered bulks compared to other general processes (about 18%. While sintered samples blended with micro Ti showed presence of microstructural cracks, the samples with 1-2% nano Ti had less or no cracks on them. Overall, the inclusion of nano Ti indicated improvement in mechanical properties of TiO2 nanopowders sintered preforms as opposed to micro Ti-added TiO2.

  1. Corrosion Behavior of Ti/TiN Film Coated on AISI 304 Stainless Steel

    Energy Technology Data Exchange (ETDEWEB)

    Choe, Han Cheol [Kwangyang College, Gwangyang (Korea, Republic of); Park, Ji Yoon; Kim, Kwan Hyu [Chonnam National University, Gwangju (Korea, Republic of)

    2000-06-15

    Effects of the Ti content and the presence of Ti underlayer on the corrosion behaviors of TiN coated AISI 304 stainless steel have been studied. The stainless steel containing 0.1{approx}1.0 wt% Ti were melted with a vacuum furnace and heat treated at 1050 .deg. C for 1hr for solutionization. The specimens were coated with Ti and TiN with thickness of 1 {mu}m and 2 {mu}m respectively by electron-beam physical vapour deposition (EB-PVD) method. The microstructures and phase analysis were conducted by using SEM and WDS. The coated films showed fine columnar structure. The corrosion potential obtained from the anodic polarization curves measured in H{sub 2}SO{sub 4} solution increased in proportion to the Ti content of substrate and was much higher in the specimen coated with Ti underlayer compared to the specimen without Ti underlayer. The potential-time and the current-time curves which were obtained in 0.1M H{sub 2}SO{sub 4} + 0.1M HCI solution showed that both the increase in Ti content and the presence of Ti underlayer increased the potential and decreased the current density resulting in a dense passive film and a suppress of pit formation respectively.

  2. Electronic Structures and Bonding Properties of Ti2AlC and Ti3AlC2

    Institute of Scientific and Technical Information of China (English)

    MIN Xinmin; REN Yi

    2007-01-01

    The relation among electronic structure, chemical bond and property of Ti2AlC, Ti3AlC2 and doping Si into Ti2AlC was studied by density function and the discrete variation (DFT-DVM) method. After adding Si into Ti2AlC, the interaction between Si and Ti is weaker than that between Al and Ti, and the strengths of ionic and covalent bonds decrease both. The ionic and covalent bonds in Ti3AlC2, especially in Ti-Al, are stronger than those in Ti2AlC. Therefore, in synthesis of Ti2AlC, the addition of Si enhances the Ti3AlC2 content instead of Ti2AlC. The density of state (DOS) shows that there is mixed conductor characteristic in Ti2AlC and Ti3AlC2. The DOS of Ti3AlC2 is much like that of Ti2AlC. Ti2SixAl1-x C has more obvious tendency to form a semiconductor than Ti2AlC, which is seen from the obvious difference of partial DOS between Si and Al3p.

  3. 合金元素对电弧熔炼TiC/Ti-6Al-4V复合材料中TiC生长形态的影响%Effects of Alloying Elements on Growth and Morphology of TiC in Arc-Melted TiC/Ti-6Al-4V Composites

    Institute of Scientific and Technical Information of China (English)

    曹磊; 王宏伟; 邹鹑鸣; 魏尊杰

    2010-01-01

    采用非自耗电弧熔炼制备含不同微合金元素的10vol%TiC/Ti-6Al-4V复合材料,研究不同的微量合金元素对复合材料中TiC形态的影响.结果表明,原始铸态复合材料中TiC形态主要是粗大且发达的枝晶状.而基体中加入0.3%(质量分数,下同)的Sn元素后,TiC生长被抑制,TiC形态变为细小分散的颗粒状;0.3%的Ni被加入后,增大了TiC的结晶区间,使TiC枝晶生长变得更加发达;而0.3%的Nb元素的加入,则减小了TiC的结晶区间,从而减少了初晶TiC数量,促进了共晶TiC的形成.

  4. Effect of TiC content on the microstructure and properties of Ti3SiC2-TiC composites in situ fabricated by spark plasma sintering

    International Nuclear Information System (INIS)

    Zhang Jianfeng; Wang Lianjun; Jiang Wan; Chen Lidong

    2008-01-01

    Spark plasma sintering technique was used to in situ fabricate high dense Ti 3 SiC 2 -TiC composites. The calculated TiC volume content from X-ray diffraction (XRD) is close to the theoretical one. It is found from fracture surface observation that TiC is about 1 μm, and Ti 3 SiC 2 is about 2-10 μm in grain size. The fracture modes consist of intergranular mainly for Ti 3 SiC 2 and transgranular fracture mainly for TiC. With the increasing of TiC volume content, Vickers hardness increases to the maximum value of 13 GPa for Ti 3 SiC 2 -40 vol.%TiC. Fracture toughness and flexural strength of the composites are also improved compared with those of monolithic Ti 3 SiC 2 except for Ti 3 SiC 2 -40 vol.%TiC composite. The main reasons for the sudden decrease of fracture toughness and flexural strength of Ti 3 SiC 2 -40 vol.%TiC composite can be attributed to the relatively lower density, some clusters of TiC in the composite and the transition of fracture mode from intergranular to transgranular. The thermal conductivities decreased with the addition of TiC. The minimum thermal conductivity is 22 W m deg. C -1 for Ti 3 SiC 2 -40 vol.%TiC composite

  5. Atomic Layer-Deposited TiO2 Coatings on NiTi Surface

    Science.gov (United States)

    Vokoun, D.; Racek, J.; Kadeřávek, L.; Kei, C. C.; Yu, Y. S.; Klimša, L.; Šittner, P.

    2018-02-01

    NiTi shape-memory alloys may release poisonous Ni ions at the alloys' surface. In an attempt to prepare a well-performing surface layer on an NiTi sample, the thermally grown TiO2 layer, which formed during the heat treatment of NiTi, was removed and replaced with a new TiO2 layer prepared using the atomic layer deposition (ALD) method. Using x-ray photoelectron spectroscopy, it was found that the ALD layer prepared at as low a temperature as 100 °C contained Ti in oxidation states + 4 and + 3. As for static corrosion properties of the ALD-coated NiTi samples, they further improved compared to those covered by thermally grown oxide. The corrosion rate of samples with thermally grown oxide was 1.05 × 10-5 mm/year, whereas the corrosion rate of the ALD-coated samples turned out to be about five times lower. However, cracking of the ALD coating occurred at about 1.5% strain during the superelastic mechanical loading in tension taking place via the propagation of a localized martensite band.

  6. A study of the frequency of methylation of gene promoter regions in ...

    Indian Academy of Sciences (India)

    2013-04-02

    Apr 2, 2013 ... colorectal cancer in the Taiwanese population. CHANG-CHIEH WU1 ... hypermethylation of promoter-region CpG islands is an important ... mismatch repair gene MLH1 plays an important role in dele- ..... Asia Pac. J. Clin.

  7. Effect of Ti solute on the recovery of cold-rolled V-Ti alloys

    International Nuclear Information System (INIS)

    Leguey, T.; Munoz, A.; Pareja, R.

    1999-01-01

    The recovery characteristics of cold-rolled pure V and V-Ti alloys with compositions of 0.3, 1 and 4.5 at.% Ti have been investigated by positron annihilation spectroscopy. The recovery is accomplished in two stages. Fifty percent cold rolling induces the formation of microvoids in V-0.3Ti and V-1Ti but not in V-4.5Ti. The first recovery stage in pure V, V-0.3Ti and V-1Ti starts with the dissolution of microvoids. The recovery curves of the annihilation parameters for the alloys indicate the formation of Ti-rich precipitates during the first recovery stage. These precipitates act as very efficient vacancy sinks. The second recovery stage starting for annealing temperatures above ≅1150 K is attributed to annealing of vacancies associated to the precipitates. (orig.)

  8. Dielectric enhancement of BaTiO3/SrTiO3 superlattices with embedded Ni nanocrystals

    International Nuclear Information System (INIS)

    Xiong Zhengwei; Sun Weiguo; Wang Xuemin; Jiang Fan; Wu Weidong

    2012-01-01

    Highlights: ► The BaTiO 3 /SrTiO 3 superlattices with embedded Ni NCs were successfully fabricated by L-MBE. ► The influence with the various concentrations of Ni nanocrystals embedded in BaTiO 3 /SrTiO 3 superlattices was also discussed. ► The BaTiO 3 /SrTiO 3 superlattices with lower concentration of embedded Ni NCs had higher permittivity and dielectric loss compared with the pure BaTiO 3 /SrTiO 3 superlattices. ► The dielectric enhancement of BaTiO 3 /SrTiO 3 superlattices with embedded Ni NCs was proposed to explained by Drude quasi-free-electron theory. - Abstract: The self-organized Ni nanocrystals (NCs) were embedded in BaTiO 3 /SrTiO 3 superlattices using laser molecular beam epitaxy (L-MBE). The stress of the composite films was increased with the increasing concentration of embedded Ni NCs, as investigation in stress calculation. The influence with the various concentrations of Ni NCs embedded in BaTiO 3 /SrTiO 3 superlattices was also discussed. The internal stress of the films was too strong to epitaxial growth of BaTiO 3 /SrTiO 3 superlattices. Compared with the pure BaTiO 3 /SrTiO 3 superlattices, the BaTiO 3 /SrTiO 3 superlattices with lower concentration of embedded Ni NCs had higher permittivity and dielectric loss. Furthermore, the dielectric enhancement of BaTiO 3 /SrTiO 3 superlattices with embedded Ni NCs was proposed to explained by Drude quasi-free-electron theory.

  9. Phase equilibria among α-Fe(Al, Cr, Ti), liquid and TiC and the formation of TiC in Fe3Al-based alloys

    International Nuclear Information System (INIS)

    Kobayashi, Satoru; Schneider, Andre; Zaefferer, Stefan; Frommeyer, Georg; Raabe, Dierk

    2005-01-01

    In the context of the development of high-strength Fe 3 Al-based alloys, phase equilibria among α-Fe(Al, Cr, Ti), liquid and TiC phases in the Fe-Al-Cr-Ti-C quinary system and the formation of TiC were determined. A pseudo-eutectic trough (L α + L + TiC) exists at 1470 deg C at around Fe-26Al-5Cr-2Ti-1.7C on the vertical section between Fe-26Al-5Cr (α) and Ti-46C (TiC) in at.%. Large faceted TiC precipitates form from the melt after the formation of primary α phase even in hypoeutectic alloys. The TiC formation is thought to be due to the composition change of the liquid towards the hypereutectic compositions by solidification of the primary α. In order to remove the faceted TiC, which are unfavourable for strengthening the material, two different processing routes have been successfully tested: (i) solidification with an increased rate to reduce the composition variation of the liquid during solidification, and (ii) unidirectional solidification to separate the light TiC precipitates from the melt

  10. A study of TiB2/TiB gradient coating by laser cladding on titanium alloy

    Science.gov (United States)

    Lin, Yinghua; Lei, Yongping; Li, Xueqiao; Zhi, Xiaohui; Fu, Hanguang

    2016-07-01

    TiB2/TiB gradient coating has been fabricated by a laser cladding technique on the surface of a Ti-6Al-4V substrate using TiB2 powder as the cladding material. The microstructure and mechanical properties of the gradient coating were analyzed by SEM, EPMA, XRD, TEM and an instrument to measure hardness. With the increasing distance from the coating surface, the content of TiB2 particles gradually decreased, but the content of TiB short fibers gradually increased. Meanwhile, the micro-hardness and the elastic modulus of the TiB2/TiB coating showed a gradient decreasing trend, but the fracture toughness showed a gradient increasing trend. The fracture toughness of the TiB2/TiB coating between the center and the bottom was improved, primarily due to the debonding of TiB2 particles and the high fracture of TiB short fibers, and the fracture position of TiB short fiber can be moved to an adjacent position. However, the debonding of TiB2 particles was difficult to achieve at the surface of the TiB2/TiB coating.

  11. Microstructure and wear of in-situ Ti/(TiN + TiB) hybrid composite layers produced using liquid phase process

    Energy Technology Data Exchange (ETDEWEB)

    Yazdi, R., E-mail: ryazdi@ut.ac.ir; Kashani-Bozorg, S.F.

    2015-02-15

    Tungsten inert gas (TIG) technique was conducted on commercially pure (CP)-Ti substrate, which was coated with h-BN-based powder mixture prior to the treatment. The treated surfaces were evaluated and characterized by means of scanning electron microscope (SEM), X-ray diffraction analysis, and electron dispersive spectrometry (EDS). The microhardness and wear experiment were also performed by using a microhardness machine and pin-on-disk tribometer. As h-BN reacted with titanium, an in-situ hybrid composite layer was formed showing near stoichiometric dendrites of TiN, platelets of TiB and interdendritic regions of α′-Ti martensite crystal structures. The population level of TiN and TiB regions were found to increase using a pre-placed powder mixture with greater h-BN content. However, the fabricated layers exhibited cracking and porosity; these were minimized by adjusting arc energy density and h-BN content of powder mixture. The microhardness value of the fabricated hybrid composite layers was found to be in the range of ∼650 HV{sub 0.2}–1000 HV{sub 0.2}; this is three to five times higher than that of the untreated CP-Ti substrate. In addition, the in-situ hybrid composite layers exhibited superior wear behavior over CP-Ti substrate; this is attributed to the formation of newly formed ceramic phases in the solidified surface layers and good coherent interface between the composite layer and CP-substrate. Meanwhile, severe adhesive wear mechanism of CP-titanium surface changed to mild abrasive one as a result of surface treatment. - Highlights: • In-situ Ti/(TiN + TiB) hybrid composite layers were synthesized by TIG processing on commercially pure titanium. • The microstructure features were characterized by several methods. • Microhardness enhanced three to five times higher than that of the CP-Ti substrate after surface modification. • The fabricated composite layers improved wear resistance of CP-titanium. • Severe adhesive wear mechanism of

  12. Influence of TiC Content on Microstructure and Properties of TiC/Cu Composite%TiC含量对TiC/Cu复合材料组织与性能的影响

    Institute of Scientific and Technical Information of China (English)

    李小池; 杨巧

    2017-01-01

    采用粉末冶金法制备了TiC/Cu复合材料,研究不同TiC含量对TiC/Cu复合材料组织与拉伸性能的影响,并利用扫描电镜、金相显微镜等对样品的表面形貌和拉伸断口形貌进行分析.结果表明,TiC与基体结合紧密且在基体中分布均匀;随着增强相TiC含量的增加,TiC/Cu复合材料的抗拉强度先增大后降低;TiC的加入明显阻碍了基体晶粒长大;当TiC质量分数为2%时,强化效果较好,TiC/Cu复合材料的塑性较好.

  13. Early stages of the mechanical alloying of TiC–TiN powder mixtures

    International Nuclear Information System (INIS)

    Mura, Giovanna; Musu, Elodia; Delogu, Francesco

    2013-01-01

    The present work focuses on the alloying behavior of TiC–TiN powder mixtures submitted to mechanical processing by ball milling. Accurate X-ray diffraction analyses indicate a progressive modification of the unit cell parameters of the TiC and TiN phases, suggesting the formation of TiC- and TiN-rich solid solutions with an increasingly larger content of solutes. Once the discrete character of the mechanical treatment is taken into due account, the smooth change of the unit cell parameters can be explained by a sequence of mutual dissolution stages related to individual collisions. At each collision, the average chemical composition of small amounts of TiC- and TiN-rich phases changes discontinuously. The discontinuous changes can be tentatively ascribed to local mass transport processes activated by the mechanical deformation of powders at collisions. -- Highlights: ► Mechanically processed TiC–TiN powder mixtures form two solid solutions. ► An analytical model was developed to describe the mechanical alloying kinetics. ► The amount of powder alloyed at collision was indirectly estimated. ► A few nanomoles of material participate in the alloying process at each collision. ► The chemical composition of the solid solutions was shown to change discontinuously.

  14. Effects of strong interactions between Ti and ceria on the structures of Ti/CeO2.

    Science.gov (United States)

    Yao, Xiao-Dan; Zhu, Kong-Jie; Teng, Bo-Tao; Yu, Cao-Ming; Zhang, Yun-Lei; Liu, Ya; Fan, Maohong; Wen, Xiao-Dong

    2016-11-30

    The effects of strong interactions between Ti and ceria on the structures of Ti/CeO 2 (111) are systematically investigated by density functional theory calculation. To our best knowledge, the adsorption energy of a Ti atom at the hollow site of CeO 2 is the highest value (-7.99 eV) reported in the literature compared with those of Au (-0.88--1.26 eV), Ag (-1.42 eV), Cu (-2.69 eV), Pd (-1.75 eV), Pt (-2.62 eV) and Sn (-3.68 eV). It is very interesting to find that Ti adatoms disperse at the hollow site of CeO 2 (111) to form surface TiO x species, instead of aggregating to form Ti metal clusters for the Ti-CeO 2 interactions that are much stronger than those of Ti-Ti ones. Ti adatoms are completely oxidized to Ti 4+ ions if they are monatomically dispersed on the next near hollow sites of CeO 2 (111) (xTi-NN-hollow); while Ti 3+ ions are observed when they locate at the near hollow sites (xTi-N-hollow). Due to the electronic repulsive effects among Ti 3+ ions, the adsorption energies of xTi-N-hollow are slightly weaker than those of xTi-NN-hollow. Simultaneously, the existence of unstable Ti 3+ ions on xTi-N-hollow also leads to the restructuring of xTi-N-hollow by surface O atoms of ceria transferring to the top of Ti 3+ ions, or oxidation by O 2 adsorption and dissociation. Both processes improve the stability of the xTi/CeO 2 system by Ti 3+ oxidation. Correspondingly, surface TiO 2 -like species form. This work sheds light into the structures of metal/CeO 2 catalysts with strong interactions between the metal and the ceria support.

  15. Crystal structure of transition metal halides TiCl4, α-TiCl3, WCl4 and TiI2

    International Nuclear Information System (INIS)

    Troyanov, S.I.; Snigireva, E.M.

    2000-01-01

    Crystal structures of TiCl 4 , α-TiCl 3 , WCl 4 and TiI 2 are determined by x-ray diffraction method. For crystalline WCl 4 general for phases of this type space group C2/m is confirmed. Linear chains of WCl 6 octahedrons joined through the opposite edges exist in structure. Short W-W distances (2.69 A) in linear chains differentiate the structure of WCl 6 . Laminar structure of TiI 2 is belongs to CdI 2 structural type. Iodine atoms form slightly distorted hexagonal face-centered packing, titanium atoms fill up octahedral hollows in two-layer packing of iodine atoms with Ti-I distances equal 2.903 A [ru

  16. Fabrication and Mechanical Properties of Nanostructured TiC-TiAl by the Pulsed Current Activated Sintering

    Energy Technology Data Exchange (ETDEWEB)

    Kwak, Bong-Won; Shon, In-Jin [Chonbuk National University, Chonbuk (Korea, Republic of); Kim, Byung-Su [Korea Institute of Geoscience and Mineral Resources, Daejeon (Korea, Republic of); Yoon, Jin-Kook; Hong, Kyung-Tae [Korea Institute of Science and Technology, Seoul (Korea, Republic of)

    2016-08-15

    TiC-Co or TiC-Ni hard materials have been used for cutting tools. However, the high cost and the low hardness of Ni or Co, and the low corrosion resistance of the TiC-Ni and TiC-Co cermets have generated interest in recent years in using them as alternative binder phases. In this study, TiAl was used as a novel binder and consolidated by the pulsed current activated sintering(PCAS) method. Nanopowders of TiC and TiAl were fabricated using high energy ball milling. Highly dense TiC-TiAl hard materials with a relative density of up to 99.5% were sintered within three min by PCAS. Not only the hardness but also the fracture toughness of the TiC-10 vol%TiAl were better than those of TiC-10 vol%Ni or TiC-10 vol%Co.

  17. Fabrication and Mechanical Properties of Nanostructured TiC-TiAl by the Pulsed Current Activated Sintering

    International Nuclear Information System (INIS)

    Kwak, Bong-Won; Shon, In-Jin; Kim, Byung-Su; Yoon, Jin-Kook; Hong, Kyung-Tae

    2016-01-01

    TiC-Co or TiC-Ni hard materials have been used for cutting tools. However, the high cost and the low hardness of Ni or Co, and the low corrosion resistance of the TiC-Ni and TiC-Co cermets have generated interest in recent years in using them as alternative binder phases. In this study, TiAl was used as a novel binder and consolidated by the pulsed current activated sintering(PCAS) method. Nanopowders of TiC and TiAl were fabricated using high energy ball milling. Highly dense TiC-TiAl hard materials with a relative density of up to 99.5% were sintered within three min by PCAS. Not only the hardness but also the fracture toughness of the TiC-10 vol%TiAl were better than those of TiC-10 vol%Ni or TiC-10 vol%Co.

  18. Contribution to the study of U-Ti and U-Pu-Ti carbides

    International Nuclear Information System (INIS)

    Milet, C.A.

    1968-01-01

    After having discussed the reasons to use (U,Pu) carbides as fast reactor fuel, we examine the influence of the addition of titanium to these carbides. A preliminary study has been done on the system of U-C-Ti and some properties have been measured such as: density, thermal expansion, electrical resistivity, atmospheric corrosion and compatibility with stainless steel. The systems U-Pu-C-Ti (Pu/U + Pu equal to 15 per cent) and U-C-Ti have been found to be very similar. There exists a two phases region (U,Pu)C + TiC, an eutectic between (U,Pu)C and TiC for approximately 15 at %. The solubilities of U + Pu in TiC and of Ti in (U,Pu)C is less than 1 % at. The addition of titanium does not markedly change thermal expansion coefficients of (U,Pu)C. However the resistance to atmospheric corrosion and compatibility with stainless steel is improved. Thermal conductivity, calculated from electrical resistivity, has increased. On the other side, the density of fissile material is lowered. The combination of (U,Pu)C + TiC seems to be the most promising alloy for application as nuclear fuel. (author) [fr

  19. The research of Ti-rich zone on the interface between TiCx and aluminum melt and the formation of Ti3Al in rapid solidified Al-Ti-C master alloys

    International Nuclear Information System (INIS)

    Jiang Kun; Ma Xiaoguang; Liu Xiangfa

    2009-01-01

    In the present work, the thermodynamic tendency of formation of Ti-rich zone on the interface between TiC x and aluminum melt is calculated and a high titanium concentration can exist in the zone according to the thermodynamic calculation. Rapid solidified Al-5Ti-0.5C master alloy is analyzed by X-ray diffraction (XRD) and transmission electronic microscopy (TEM). The appearance of Ti 3 Al in the master alloy results from the existence of high-concentration Ti-rich zone.

  20. In situ synthesized TiB-TiN reinforced Ti6Al4V alloy composite coatings: microstructure, tribological and in-vitro biocompatibility.

    Science.gov (United States)

    Das, Mitun; Bhattacharya, Kaushik; Dittrick, Stanley A; Mandal, Chitra; Balla, Vamsi Krishna; Sampath Kumar, T S; Bandyopadhyay, Amit; Manna, Indranil

    2014-01-01

    Wear resistant TiB-TiN reinforced Ti6Al4V alloy composite coatings were deposited on Ti substrate using laser based additive manufacturing technology. Ti6Al4V alloy powder premixed with 5wt% and 15wt% of boron nitride (BN) powder was used to synthesize TiB-TiN reinforcements in situ during laser deposition. Influences of laser power, scanning speed and concentration of BN on the microstructure, mechanical, in vitro tribological and biological properties of the coatings were investigated. Microstructural analysis of the composite coatings showed that the high temperature generated due to laser interaction with Ti6Al4V alloy and BN results in situ formation of TiB and TiN phases. With increasing BN concentration, from 5wt% to 15wt%, the Young's modulus of the composite coatings, measured by nanoindentation, increased from 170±5GPa to 204±14GPa. In vitro tribological tests showed significant increase in the wear resistance with increasing BN concentration. Under identical test conditions TiB-TiN composite coatings with 15wt% BN exhibited an order of magnitude less wear rate than CoCrMo alloy-a common material for articulating surfaces of orthopedic implants. Average top surface hardness of the composite coatings increased from 543±21HV to 877±75HV with increase in the BN concentration. In vitro biocompatibility and flow cytometry study showed that these composite coatings were non-toxic, exhibit similar cell-materials interactions and biocompatibility as that of commercially pure titanium (CP-Ti) samples. In summary, excellent in vitro wear resistance, high stiffness and suitable biocompatibility make these composite coatings as a potential material for load-bearing articulating surfaces towards orthopaedic implants. © 2013 Elsevier Ltd. All rights reserved.

  1. Effect Mechanism of TiAl3 on the Precipitation of TiC Particles in Aluminum Melt%TiAl3对TiC粒子在铝熔体中沉淀特性的影响机理

    Institute of Scientific and Technical Information of China (English)

    丁万武; 夏天东; 赵文军

    2013-01-01

    采用金相显微镜(MEF3)、电子探针(EPMA)等研究TiC和TiAl3细化工业纯铝时TiAl3的存在对TiC在铝熔体中沉淀特性的影响规律,分析其影响机制.结果表明:TiC在铝熔体中单独存在时沉淀速率快,在较短时间保温后,大量TiC发生沉淀,从而限制其异质形核作用;当TiC和TiAl3在铝熔体中共同存在时,TiC沉淀速率变缓,在较长时间保温后,只有少量TiC发生沉淀,表现出较强形核能力和抗晶粒细化衰退能力.其影响机理是:TiAl3在铝熔体中增大了TiC粒子的沉降阻力,使得TiC粒子沉降速率变缓而在凝固时成为α(Al)的异质形核质点.Al Ti-C合金细化作用衰减是由TiC发生沉淀引起.%The effect of TiAl3 on the precipitation of TiC particles in aluminum melt was studied when TiC and TiAl3 refining industry aluminum, and the mechanism was discussed using MEF3 and EPMA. The results show that TiC particles deposit quickly and have poor nucleation capability when TiC is used as the α(Al) nucleation phase only, but when TiC and TiAl3 common as the α(Al) nucleation phase, TiC particles deposit more and more slow. Even after long time, there was only a small a-mount of precipitation. It demonstrated better nucleation and higher resistance to grain refining fading. The reason is that TiAl3 increase the settlement resistance of TiC particles. The refinement effect fading of Al-Ti-C master alloy is caused by TiC precipitation.

  2. Transformation from Al3BC phase to doped TiB2 or TiC particles in Al–Ti melts

    International Nuclear Information System (INIS)

    Tian, Wenjie; Li, Pengting; Gao, Tong; Nie, Jinfeng; Liu, Xiangfa

    2013-01-01

    Highlights: ► The reaction of phase Al 3 BC with Ti was investigated. ► The transformation leads to the formation of C-doped TiB 2 and B-doped TiC. ► The doped particles show macroporous and lamellar morphologies. ► A model was proposed to illustrate the transformation mechanism. ► Grain refinement performance of the Al–5Ti–0.8B–0.2C on A356 alloy is excellent. -- Abstract: An Al–8B–2C master alloy was added into Al–Ti melts to study the reaction of Al 3 BC phase with Ti. As a result, a new Al–5Ti–0.8B–0.2C master alloy was fabricated. The microstructures were studied by field emission scanning electron microscope (FESEM), X-ray diffraction (XRD) and transmission electron microscope (TEM). The analysis indicates that C-doped TiB 2 and B-doped TiC which show macroporous and lamellar morphologies are transformed from Al 3 BC. The transformation mechanism is also discussed in this work. Furthermore, the grain refinement performance of the Al–5Ti–0.8B–0.2C on A356 alloy was investigated

  3. Electrochemical behavior of hydroxyapatite/TiN multi-layer coatings on Ti alloys

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Eun-Ju [Department of Dental Materials, Research Center of Nano-Interface Activation for Biomaterials, School of Dentistry, Chosun University (Korea, Republic of); Jeong, Yong-Hoon [Biomechanics and Tissue Engineering Laboratory, Division of Orthodontics, College of Dentistry, The Ohio State University, Columbus, OH (United States); Choe, Han-Cheol, E-mail: hcchoe@chosun.ac.kr [Department of Dental Materials, Research Center of Nano-Interface Activation for Biomaterials, School of Dentistry, Chosun University (Korea, Republic of); Brantley, William A. [Division of Restorative Science and Prosthodontics, College of Dentistry, The Ohio State University, Columbus, OH (United States)

    2014-12-01

    The electrochemical behavior of hydroxyapatite (HA) and titanium nitride (TiN) multi-layer coatings on Ti–Nb–Zr alloys was investigated by a variety of surface analytical methods. The HA/TiN layers were deposited using a magnetron sputtering system. The HA target was made of human tooth-ash sintered at 1300 °C for 1 h and had an average Ca/P ratio of 1.9. From X-ray diffraction patterns, the Ti–29Nb–5Zr alloy was composed entirely of equiaxed β-phase exhibiting the principal (110) reflection, and the coating exhibited the (111) and (200) reflections for TiN and the (112) and (202) reflections for HA. At the coating surface the HA films consisted of granular particles, and the surface roughness was 4.22 nm. The thickness of the coating layers increased in the order of HA/TiN (lowest), TiN, and HA (highest). Potentiodynamic polarization measurements revealed that the corrosion current density was the lowest, and the corrosion potential and polarization resistance the highest, when the Ti–29Nb–5Zr surface was covered by the HA/TiN film, compared to solely HA or TiN films. - Highlights: • HA/TiN films were deposited by magnetron sputtering on a Ti–29Nb–5Zr biomedical alloy. • The corrosion current density for the HA/TiN films was lower than that of the non-coated alloy. • The polarization resistance of the HA/TiN films was higher than that of the non-coated alloy.

  4. Electrochemical behavior of hydroxyapatite/TiN multi-layer coatings on Ti alloys

    International Nuclear Information System (INIS)

    Kim, Eun-Ju; Jeong, Yong-Hoon; Choe, Han-Cheol; Brantley, William A.

    2014-01-01

    The electrochemical behavior of hydroxyapatite (HA) and titanium nitride (TiN) multi-layer coatings on Ti–Nb–Zr alloys was investigated by a variety of surface analytical methods. The HA/TiN layers were deposited using a magnetron sputtering system. The HA target was made of human tooth-ash sintered at 1300 °C for 1 h and had an average Ca/P ratio of 1.9. From X-ray diffraction patterns, the Ti–29Nb–5Zr alloy was composed entirely of equiaxed β-phase exhibiting the principal (110) reflection, and the coating exhibited the (111) and (200) reflections for TiN and the (112) and (202) reflections for HA. At the coating surface the HA films consisted of granular particles, and the surface roughness was 4.22 nm. The thickness of the coating layers increased in the order of HA/TiN (lowest), TiN, and HA (highest). Potentiodynamic polarization measurements revealed that the corrosion current density was the lowest, and the corrosion potential and polarization resistance the highest, when the Ti–29Nb–5Zr surface was covered by the HA/TiN film, compared to solely HA or TiN films. - Highlights: • HA/TiN films were deposited by magnetron sputtering on a Ti–29Nb–5Zr biomedical alloy. • The corrosion current density for the HA/TiN films was lower than that of the non-coated alloy. • The polarization resistance of the HA/TiN films was higher than that of the non-coated alloy

  5. Fabrication of Powder Metallurgy Pure Ti Material by Using Thermal Decomposition of TiH2

    Science.gov (United States)

    Mimoto, Takanori; Nakanishi, Nozomi; Umeda, Junko; Kondoh, Katsuyoshi

    Titanium (Ti) and titanium alloys have been interested as an engineering material because they are widely used across various industrial applications, for example, motorcycle, automotive and aerospace industries, due to their light weight, high specific strength and superior corrosion resistance. Ti materials are particularly significant for the aircraft using carbon/carbon (C/C) composites, for example, carbon fiber reinforced plastics (CFRP), because Ti materials are free from the problem of contact corrosion between C/C composites. However, the applications of Ti materials are limited because of their high cost. From a viewpoint of cost reduction, cost effective process to fabricate Ti materials is strongly required. In the present study, the direct consolidation of titanium hydride (TiH2) raw powders in solid-state was employed to fabricate pure Ti bulk materials by using thermal decomposition of TiH2. In general, the production cost of Ti components is expensive due to using commercially pure (CP) Ti powders after dehydrogenation. On the other hand, the novel process using TiH2 powders as starting materials is a promising low cost approach for powder metallurgy (P/M) Ti products. Furthermore, this new process is also attractive from a viewpoint of energy saving because the dehydrogenation is integrated into the sintering process. In this study, TiH2 raw powders were directly consolidated by conventional press technique at 600 MPa to prepare TiH2 powder compacted billets. To thermally decompose TiH2 and obtain sintered pure Ti billets, the TiH2 powder billets were heated in the integrated sintering process including dehydrogenation. The hot-extruded pure Ti material, which was heat treated at 1273 K for 180 min in argon gas atmosphere, showed tensile strength of 701.8 MPa and elongation of 27.1%. These tensile properties satisfied the requirements for JIS Ti Grade 4. The relationship between microstructures, mechanical properties response and heat treatment

  6. Structure characterization of Ni/NiO and Ti/TiO2 interfaces

    International Nuclear Information System (INIS)

    Lamine, Brahim

    1983-01-01

    This research thesis reports the structure characterization of Ni-NiO and Ti-TiO 2 interfaces through an in-situ investigation of thin blade oxidation, of oxide germination and growth, and through a determination of mutual metal/oxide orientation relationships. Thin films of TiO 2 have also been characterized and the study of the influence of vacuum annealing on TiO 2 layer structure and morphology has been attempted. The examination of metal-oxide interface reveals a duplex structure of NiO and TiO 2 layers, and a preferential grain boundary oxidation of the underlying metal [fr

  7. Synthesis and characterization of Ag-doped TiO2 nanotubes on Ti-6Al-4V and Ti-6Al-7Nb alloy

    Science.gov (United States)

    Ulfah, Ika Maria; Bachtiar, Boy M.; Murnandityas, Arnita Rut; Slamet

    2018-05-01

    The present paper is focused on comparative behavior of nanotubes growth on Ti-6Al-4V and Ti-6Al-7Nb alloy using electrochemical anodization method. These alloys were anodized in electrolytes solution containing glycerol, water and 0.5wt.% of NH4F. Silver-doped TiO2 nanotubes were synthesized using photo-assisted deposition (PAD) at various Ag loading concentration in 0.05 M, 0.10 M, and 0.15 M. The phase composition and morphological characteristics were investigated by XRD and FESEM/EDX, respectively. The surface wettability was measured by contact angle meter. The results showed that TiO2 nanotubes can be grown on these surface alloys. XRD profiles revealed crystal formation of anatase, rutile and Ag on these surface alloys. According to FESEM images, the average nanotube diameter of Ti-6Al-4V alloy and Ti-6Al-7Nb alloy are 134 nm and 120 nm, respectively. EDX-Mapping analysis showed that Ag desposited over surface of TiO2 nanotubes. The surface wettability indicated hydrophilicity properties on Ti-4Al-4V alloy and Ti-6Al-7Nb alloy surface. This study may contribute to the development of silver-doped TiO2 nanotubes on Ti-6Al-4V alloy and Ti-6Al-7Nb alloy can be considered in various photocatalytic applications such as biomedical devicesdue to photocatalytic mechanism and antibacterial ability.

  8. Low modulus and bioactive Ti/α-TCP/Ti-mesh composite prepared by spark plasma sintering.

    Science.gov (United States)

    Guo, Yu; Tan, Yanni; Liu, Yong; Liu, Shifeng; Zhou, Rui; Tang, Hanchun

    2017-11-01

    A titanium mesh scaffold composite filled with Ti/α-TCP particles was prepared by spark plasma sintering (SPS). The microstructures and interfacial reactions of the composites were investigated by scanning electron microscopy (SEM), Energy Dispersive Spectroscopy (EDS) and X-ray diffraction (XRD) analyses. The compressive strength and elastic modulus were also measured. In vitro bioactivity and biocompatibility was evaluated by using simulated body fluid and cells culture, respectively. After high temperature sintering, Ti oxides, Ti x P y and CaTiO 3 were formed. The formation of Ti oxides and Ti x P y were resulted from the diffusion of O and P elements from α-TCP to Ti. CaTiO 3 was the reaction product of Ti and α-TCP. The composite of 70Ti/α-TCP incorporated with Ti mesh showed a high compressive strength of 589MPa and a low compressive modulus of 30GPa. The bioactivity test showed the formation of a thick apatite layer on the composite and well-spread cells attachment. A good combination of mechanical properties and bioactivity indicated a high potential application of Ti/α-TCP/Ti-mesh composite for orthopedic implants. Copyright © 2017. Published by Elsevier B.V.

  9. Reactive Ni/Ti nanolaminates

    International Nuclear Information System (INIS)

    Adams, D. P.; Bai, M. M.; Rodriguez, M. A.; McDonald, J. P.; Jones, E. Jr.; Brewer, L.; Moore, J. J.

    2009-01-01

    Nickel/titanium nanolaminates fabricated by sputter deposition exhibited rapid, high-temperature synthesis. When heated locally, self-sustained reactions were produced in freestanding Ni/Ti multilayer foils characterized by average propagation speeds between ∼0.1 and 1.4 m/s. The speed of a propagating reaction front was affected by total foil thickness and bilayer thickness (layer periodicity). In contrast to previous work with compacted Ni-Ti powders, no preheating of Ni/Ti foils was required to maintain self-propagating reactions. High-temperature synthesis was also stimulated by rapid global heating demonstrating low ignition temperatures (T ig )∼300-400 deg. C for nanolaminates. Ignition temperature was influenced by bilayer thickness with more coarse laminate designs exhibiting increased T ig . Foils reacted in a vacuum apparatus developed either as single-phase B2 cubic NiTi (austenite) or as a mixed-phase structure that was composed of monoclinic B19 ' NiTi (martensite), hexagonal NiTi 2 , and B2 NiTi. Single-phase, cubic B2 NiTi generally formed when the initial bilayer thickness was made small.

  10. Early stages of the mechanical alloying of TiC-TiN powder mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Mura, Giovanna [Dipartimento di Ingegneria Elettrica ed Elettronica, Universita degli Studi di Cagliari, via Marengo 2, 09123 Cagliari (Italy); Musu, Elodia [Industrial Telemicroscopy Laboratory, Sardegna Ricerche, Polaris, Technology Park of Sardinia, Edificio 3, Loc. Piscinamanna, 09010 Pula (Italy); Delogu, Francesco, E-mail: francesco.delogu@dimcm.unica.it [Dipartimento di Ingegneria Meccanica, Chimica, e dei Materiali, Universita degli Studi di Cagliari, via Marengo 2, I-09123 Cagliari (Italy)

    2013-01-15

    The present work focuses on the alloying behavior of TiC-TiN powder mixtures submitted to mechanical processing by ball milling. Accurate X-ray diffraction analyses indicate a progressive modification of the unit cell parameters of the TiC and TiN phases, suggesting the formation of TiC- and TiN-rich solid solutions with an increasingly larger content of solutes. Once the discrete character of the mechanical treatment is taken into due account, the smooth change of the unit cell parameters can be explained by a sequence of mutual dissolution stages related to individual collisions. At each collision, the average chemical composition of small amounts of TiC- and TiN-rich phases changes discontinuously. The discontinuous changes can be tentatively ascribed to local mass transport processes activated by the mechanical deformation of powders at collisions. -- Highlights: Black-Right-Pointing-Pointer Mechanically processed TiC-TiN powder mixtures form two solid solutions. Black-Right-Pointing-Pointer An analytical model was developed to describe the mechanical alloying kinetics. Black-Right-Pointing-Pointer The amount of powder alloyed at collision was indirectly estimated. Black-Right-Pointing-Pointer A few nanomoles of material participate in the alloying process at each collision. Black-Right-Pointing-Pointer The chemical composition of the solid solutions was shown to change discontinuously.

  11. Preparation and Mechanical Properties of TiC-Fe Cermets and TiC-Fe/Fe Bilayer Composites

    Science.gov (United States)

    Zheng, Yong; Zhou, Yang; Li, Runfeng; Wang, Jiaqi; Chen, Lulu; Li, Shibo

    2017-10-01

    TiC-Fe cermets and TiC-Fe/Fe bilayer composites consisting of a pure Fe layer and a TiC-Fe cermets layer were fabricated by hot-pressing sintering. The pure Fe layer contributes to the toughness of composites, and the TiC-Fe cermets layer endows the composites with an improved tensile strength and hardness. The effect of TiC contents (30-60 vol.%) on the mechanical properties of TiC-Fe cermets and TiC-Fe/Fe bilayer composites was investigated. Among the TiC-Fe cermets, the 40 vol.% TiC-Fe cermets possessed the highest tensile strength of 581 MPa and Vickers hardness of 5.1 GPa. The maximum fracture toughness of 17.0 MPa m1/2 was achieved for the TiC-Fe cermets with 30 vol.% TiC. For the TiC-Fe/Fe bilayer composites, the 40 vol.% TiC-Fe/Fe bilayer composite owns the maximum tensile strength of 588 MPa, which is higher than that of 40 vol.% TiC-Fe cermets. In addition, the 33.5% increment of tensile strength of 30 vol.% TiC-Fe/Fe bilayer composite comparing with the 30 vol.% TiC-Fe cermets, which is attributed to the 30 vol.% TiC-Fe/Fe bilayer composite exhibited the largest interlaminar shear strength of 335 MPa. The bilayer composites are expected to be used as wear resistance components in some heavy wear conditions.

  12. Electrolytic Production of Ti5Si3/TiC Composites by Solid Oxide Membrane Technology

    Science.gov (United States)

    Zheng, Kai; Zou, Xingli; Xie, Xueliang; Lu, Changyuan; Chen, Chaoyi; Xu, Qian; Lu, Xionggang

    2018-02-01

    This paper investigated the electrolytic production of Ti5Si3/TiC composites from TiO2/SiO2/C in molten CaCl2. The solid-oxide oxygen-ion-conducting membrane tube filled with carbon-saturated liquid tin was served as the anode, and the pressed spherical TiO2/SiO2/C pellet was used as the cathode. The electrochemical reduction process was carried out at 1273 K and 3.8 V. The characteristics of the obtained cathode products and the reaction mechanism of the electroreduction process were studied by a series of time-dependent electroreduction experiments. It was found that the electroreduction process generally proceeds through the following steps: TiO2/SiO2/C → Ti2O3, CaTiO3, Ca2SiO4, SiC → Ti5Si3, TiC. The morphology observation and the elemental distribution analysis indicate that the reaction routes for Ti5Si3 and TiC products are independent during the electroreduction process.

  13. Optical and structural properties of TiO{sub 2}/Ti/Ag/TiO{sub 2} and TiO{sub 2}/ITO/Ag/ITO/TiO{sub 2} metal-dielectric multilayers by RF magnetron sputtering for display application

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jang-Hoon; Lee, Seung-Hyu; Hwangbo, Chang-Kwon [Inha University, Incheon (Korea, Republic of); Lee, Kwang-Su [Quantum Photonic Science Research Center, Hanyang University, Seoul (Korea, Republic of)

    2004-03-15

    Electromagnetic-interference (EMI) shielding and near-infrared (NIR) cutoff filters for plasma display panels, based on fundamental structures (ITO/Ag/ITO), (TiO{sub 2}/Ti/Ag/TiO{sub 2}) and (TiO{sub 2}/ITO/Ag/ITO/TiO{sub 2}), were designed and prepared by RF-magnetron sputtering. The optical, structural and electrical properties of the filters were investigated by using spectrophotometry, Auger electron spectroscopy, X-ray photoelectron spectroscopy, Rutherford backscattering spectroscopy, atomic force microscopy and four-point-probe measurements. The results show that ITO films as the barriers and base layers lead to higher transmittance in the visible spectrum and smoother surface roughness than Ti metal barriers, while maintaining high NIR cutoff characteristics and chemical stability, which may be attributed to the lower absorption in the interfacial layers and better protection of the Ag layers by the ITO layers.

  14. Ab initio calculations of PbTiO{sub 3}/SrTiO{sub 3} (001) heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Eglitis, R.I.; Piskunov, S.; Zhukovskii, Yu.F. [Institute of Solid State Physics, University of Latvia, 8 Kengaraga Str., 1063 Riga (Latvia)

    2016-12-15

    We performed ab initio calculations for the PbTiO{sub 3}/SrTiO{sub 3} (001) heterostructures. For both PbO and TiO{sub 2}-terminations of the PbTiO{sub 3} (001) thin film, augmented on the SrTiO{sub 3} (001) substrate, the magnitudes of atomic relaxations Δz increases as a function of the number of augmented monolayers. For both terminations of the augmented PbTiO{sub 3} (001) nanothin film, all upper, third and fifth monolayers are displaced inwards (Δz is negative), whereas all second, fourth and sixth monolayers are displaced outwards (Δz is positive). The B3PW calculated PbTiO{sub 3}/SrTiO{sub 3} (001) heterostructure band gaps, independently from the number of augmented layers, are always smaller than the PbTiO{sub 3} and SrTiO{sub 3} bulk band gaps. For both PbO and TiO{sub 2}-terminated PbTiO{sub 3}/SrTiO{sub 3}(001) heterostructures, their band gaps are reduced due to the increased number of PbTiO{sub 3} (001) monolayers. The band gaps of PbO-terminated augmented PbTiO{sub 3} (001) films are always larger than those for TiO{sub 2}-terminated PbTiO{sub 3} (001) thin films. The only exception is the case of 7-layer PbO-terminated and 8-layer TiO{sub 2}-terminated augmented PbTiO{sub 3} (001) thin films, where their band gaps both are equal to 2.99 eV. For each monolayer of the SrTiO{sub 3} (001) substrate, charge magnitudes always are more than several times larger, than for each monolayer in the augmented PbTiO{sub 3} (001) thin film. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. Wear evaluation of WC inserts coated with TiN/TiAlN multinanolayers

    OpenAIRE

    Moreno, L. H.; Ciacedo, J. C.; Martinez, F.; Bejarano, G.; Battaille, T. S.; Prieto, P.

    2010-01-01

    TiN/TiAlN multilayers were deposited by radio frequency, r.f., reactive magnetron sputtering by using titanium and aluminum targets with 10 cm diameter and 99.99% purity in an argon/nitrogen atmosphere, applying a substrate temperature of 300 ºC. WC inserts were used as substrates to improve the mechanical and tribological properties of TiN/TiAlN multilayered coatings compared to other types of coatings like TiAlN monolayers and to manage greater efficiency of these coatings in different indu...

  16. Instability of TiC and TiAl3 compounds in Al-10Mg and Al-5Cu alloys by addition of Al-Ti-C master alloy

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The performance of Al-Ti-C master alloy in refining Al-10Mg and A1-5Cu alloys was studied by using electron probe micro-analyzer (EPMA) and X-ray diffractometer (XRD) analysis.The results indicate that there are obvious fading phenomena in both Al-10Mg and Al-5Cu alloys with the addition of Al-5Ti-0.4C refiner which contains TiC and TiAl3 compounds.Mg element has no influence on the stability of TiC and TiAl3, while TiC particles in Al-10Mg alloy react with Al to form Al4C3 particles, resulting in the refinement fading.However, TiC particles are relatively stable in Al-5Cu alloy, while TiAl3 phase reacts with Al2Cu to produce a new phase Ti(Al, Cu)2, which is responsible for the refinement fading in Al-5Cu alloy.These indicate that the refinement fading will not occur only when both the TiC particles and TiAl3 compound of Al-Ti-C refiner are stable in Al alloys.

  17. Microstructure and kinetics of a functionally graded NiTi-TiC x composite produced by combustion synthesis

    International Nuclear Information System (INIS)

    Burkes, Douglas E.; Moore, John J.

    2007-01-01

    Production of a NiTi-TiC x functionally graded material (FGM) composite is possible through use of a combustion synthesis (CS) reaction employing the propagating mode (SHS). The NiTi-TiC x FGM combines the well-known and understood superelastic and shape memory capabilities of NiTi with the high hardness, wear and corrosion resistance of TiC x . The material layers were observed as functionally graded both in composition and porosity with distinct interfaces, while still maintaining good material interaction and bonding. XRD of the FGM composite revealed the presence of TiC x with equi-atomic NiTi and minor NiTi 2 and NiTi 3 phases. The TiC x particle size decreased with increasing NiTi content. Microindentation performed across the length of the FGM revealed a decrease in hardness as the NiTi content increased

  18. Formation of Al3Ti/Mg composite by powder metallurgy of Mg–Al–Ti system

    Directory of Open Access Journals (Sweden)

    Zi R Yang et al

    2008-01-01

    Full Text Available An in situ titanium trialuminide (Al3Ti-particle-reinforced magnesium matrix composite has been successfully fabricated by the powder metallurgy of a Mg–Al–Ti system. The reaction processes and formation mechanism for synthesizing the composite were studied by differential scanning calorimetry (DSC, x-ray diffractometry (XRD, scanning electron microscopy (SEM and energy-dispersive x-ray spectroscopy (EDS. Al3Ti particles are found to be synthesized in situ in the Mg alloy matrix. During the reaction sintering of the Mg–Al–Ti system, Al3Ti particles are formed through the reaction of liquid Al with as-dissolved Ti around the Ti particles. The formed intermetallic particles accumulate at the original sites of the Ti particles. As sintering time increases, the accumulated intermetallic particles disperse and reach a relatively homogeneous distribution in the matrix. It is found that the reaction process of the Mg–Al–Ti system is almost the same as that of the Al–Ti system. Mg also acts as a catalytic agent and a diluent in the reactions and shifts the reactions of Al and Ti to lower temperatures. An additional amount of Al is required for eliminating residual Ti and solid-solution strengthening of the Mg matrix.

  19. Formation of Al3Ti/Mg composite by powder metallurgy of Mg-Al-Ti system.

    Science.gov (United States)

    Yang, Zi R; Qi Wang, Shu; Cui, Xiang H; Zhao, Yu T; Gao, Ming J; Wei, Min X

    2008-07-01

    An in situ titanium trialuminide (Al 3 Ti)-particle-reinforced magnesium matrix composite has been successfully fabricated by the powder metallurgy of a Mg-Al-Ti system. The reaction processes and formation mechanism for synthesizing the composite were studied by differential scanning calorimetry (DSC), x-ray diffractometry (XRD), scanning electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDS). Al 3 Ti particles are found to be synthesized in situ in the Mg alloy matrix. During the reaction sintering of the Mg-Al-Ti system, Al 3 Ti particles are formed through the reaction of liquid Al with as-dissolved Ti around the Ti particles. The formed intermetallic particles accumulate at the original sites of the Ti particles. As sintering time increases, the accumulated intermetallic particles disperse and reach a relatively homogeneous distribution in the matrix. It is found that the reaction process of the Mg-Al-Ti system is almost the same as that of the Al-Ti system. Mg also acts as a catalytic agent and a diluent in the reactions and shifts the reactions of Al and Ti to lower temperatures. An additional amount of Al is required for eliminating residual Ti and solid-solution strengthening of the Mg matrix.

  20. Nanotubular surface and morphology of Ti-binary and Ti-ternary alloys for biocompatibility

    International Nuclear Information System (INIS)

    Choe, Han-Cheol

    2011-01-01

    The nanotubular surface of Ti-binary and Ti-ternary alloys for biomaterials has been investigated using various methods of surface characterization. Binary Ti-xNb (x = 10, 20, 30, and 40 wt.%) and ternary Ti-30Ta-xNb (x = 3, 7 and 15 wt.%) alloys were prepared by using the high-purity sponges; Ti, Ta and Zr spheres. The nanotube on the alloy surface was formed in 1.0 M H 3 PO 4 with small additions of NaF (0.5 and 0.8 wt.%), using a potentiostat. For cell proliferation, an MC3T3-E1 mouse osteoblast was used. The surface characteristics were investigated using field-emission scanning electron microscope, energy dispersive spectroscopy, and X-ray photoelectron spectroscopy. Binary Ti-xZr alloys had a lamellar and a needle-like structure, whereas, ternary Ti-30Ta-xZr alloys had equiaxed grains with a lamellar martensitic α' structure. The thickness of the needle-like laths of the α-phase increased as the Zr content increased. The nanotubes formed on the α phase and β phase showed a different size and shape appearance with Zr content. As the Zr content increased from 3 to 40 wt.%, the diameter of the nanotubes in Ti-xZr and Ti-30Ta-xZr alloy decreased from 200 nm to 50 nm. The nanotubular Ti-30Ta-15Zr alloy surface with a diameter of 50 nm provided a good osseointegration; cell proliferation, migration and differentiation.

  1. Corrosion behaviour of amorphous Ti 48 Cu 52 , Ti 50 Cu 50 and Ti ...

    Indian Academy of Sciences (India)

    ... Ti60Ni40 in 0.5 M HNO3, 0.5 M H2SO4 and 0.5 M NaOH aqueous media at room temperature. ... maximum for Ti48Cu52 alloy in all the three aqueous media as compared to the remaining two alloys. ... Bulletin of Materials Science | News.

  2. Preparation and mechanical properties of in situ TiC{sub x}–Ni (Si, Ti) alloy composites

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Wenjuan [Institute of Materials Science and Engineering, School of Mechanical, Electronic and Control Engineering, Beijing Jiaotong University, Beijing 100044 (China); Zhai, Hongxiang, E-mail: hxzhai@sina.com [Institute of Materials Science and Engineering, School of Mechanical, Electronic and Control Engineering, Beijing Jiaotong University, Beijing 100044 (China); Chen, Lin; Huang, Zhenying [Institute of Materials Science and Engineering, School of Mechanical, Electronic and Control Engineering, Beijing Jiaotong University, Beijing 100044 (China); Bei, Guoping; Baumgärtner, Christoph; Greil, Peter [Department of Materials Science (Glass and Ceramics), University of Erlangen-Nuernberg, Martensstr. 5, 91058 Erlangen (Germany)

    2014-10-20

    Novel in situ TiC{sub x} reinforced Ni (Si, Ti) alloy composites with superior mechanical properties were prepared at 1250 °C for 30 min by pressureless sintering Ti{sub 3}SiC{sub 2} (10 and 20 vol%) and Ni as precursors. The Ti{sub 3}SiC{sub 2} particles decomposed into substoichiometric TiC{sub x} phase, while the additional Si and partial Ti atoms derived from Ti{sub 3}SiC{sub 2} diffused into Ni matrix to form Ni (Si, Ti) alloy. The in situ formed TiC{sub x} phases are mainly dispersed on the grain boundaries of the Ni (Si, Ti) alloying, forming a strong skeleton and refining the microstructures of the metal matrix. The hardness, the yield stress σ{sub 0.2%} and ultimate compressive strength of 20.6 vol%TiC{sub x}–Ni(Si, Ti) composite can reach 2.15±0.04 GPa, 466.8±55.8 MPa and 733.3±78.4 MPa, respectively. The enhanced mechanical properties of TiC{sub x}–Ni(Si, Ti) composites are due to the in situ formation of TiC{sub x} skeleton, the refined microstructures of Ni (Si, Ti) alloys and solid solution effects as well as good wettability between TiC{sub x} and Ni (Si, Ti) matrix.

  3. Grinding behavior and surface appearance of (TiCp + TiBw/Ti-6Al-4V titanium matrix composites

    Directory of Open Access Journals (Sweden)

    Ding Wenfeng

    2014-10-01

    Full Text Available (TiCp + TiBw/Ti-6Al-4V titanium matrix composites (PTMCs have broad application prospects in the aviation and nuclear field. However, it is a typical difficult-to-cut material due to high hardness of the reinforcements, high strength and low thermal conductivity of Ti-6Al-4V alloy matrix. Grinding experiments with vitrified CBN wheels were conducted to analyze comparatively the grinding performance of PTMCs and Ti-6Al-4V alloy. Grinding force and force ratios, specific grinding energy, grinding temperature, surface roughness, ground surface appearance were discussed. The results show that the normal grinding force and the force ratios of PTMCs are much larger than that of Ti-6Al-4V alloy. Low depth of cut and high workpiece speed are generally beneficial to achieve the precision ground surface for PTMCs. The hard reinforcements of PTMCs are mainly removed in the ductile mode during grinding. However, the removal phenomenon of the reinforcements due to brittle fracture still exists, which contributes to the lower specific grinding energy and grinding temperature of PTMCs than Ti-6Al-4V alloy.

  4. Photoelectrochemical Water Splitting Properties of Ti-Ni-Si-O Nanostructures on Ti-Ni-Si Alloy

    Directory of Open Access Journals (Sweden)

    Ting Li

    2017-10-01

    Full Text Available Ti-Ni-Si-O nanostructures were successfully prepared on Ti-1Ni-5Si alloy foils via electrochemical anodization in ethylene glycol/glycerol solutions containing a small amount of water. The Ti-Ni-Si-O nanostructures were characterized by field-emission scanning electron microscopy (FE-SEM, energy dispersive spectroscopy (EDS, X-ray diffraction (XRD, and diffuse reflectance absorption spectra. Furthermore, the photoelectrochemical water splitting properties of the Ti-Ni-Si-O nanostructure films were investigated. It was found that, after anodization, three different kinds of Ti-Ni-Si-O nanostructures formed in the α-Ti phase region, Ti2Ni phase region, and Ti5Si3 phase region of the alloy surface. Both the anatase and rutile phases of Ti-Ni-Si-O oxide appeared after annealing at 500 °C for 2 h. The photocurrent density obtained from the Ti-Ni-Si-O nanostructure photoanodes was 0.45 mA/cm2 at 0 V (vs. Ag/AgCl in 1 M KOH solution. The above findings make it feasible to further explore excellent photoelectrochemical properties of the nanostructure-modified surface of Ti-Ni-Si ternary alloys.

  5. Improved tribological properties of TiC with porous nanostructured TiO2 intermediate layer

    International Nuclear Information System (INIS)

    Shanaghi, Ali; Ahangarani, Shahrokh; Sabour Rouhaghdam, Ali Reza; Chu, Paul K.

    2011-01-01

    Highlights: ► The porous TiO 2 nanoparticle coating is deposited as an intermediate layer on steel. ► A homogenous and low friction TiC nanostructure coating is deposited by plasma CVD. ► Intermediate layer can be determined the nucleation and growth of the TiC coating. ► The porous interlayer improves the friction and wear of the TiC nanostructure coating. - Abstract: The mismatch in the thermal expansion coefficients between TiC coatings and steel substrates and residual stress in the TiC degrade the tribological properties. In this work, a porous nanostructured TiO 2 coating is deposited as an intermediate layer on hot-work steel (H 11 ) before final deposition of the TiC film. This intermediate layer is expected to reduce the interfacial energy, decreases the thermal mismatch between TiC and steel, and improves the tribological properties. Grazing incidence X-ray diffraction (GIXRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), atomic force microscopy (AFM), and pin-on-disk are used to study the structure as well as tribological properties such as friction, wear, and hardness. Our results reveal that the porous TiO 2 interlayer improves the friction, wear, hardness, and elastic modulus of the system.

  6. Effects of Ti and TiC ceramic powder on laser-cladded Ti-6Al-4V in situ intermetallic composite

    Science.gov (United States)

    Ochonogor, O. F.; Meacock, C.; Abdulwahab, M.; Pityana, S.; Popoola, A. P. I.

    2012-12-01

    Titanium metal matrix composite (MMCs) was developed on titanium alloy (Ti-6Al-4V) substrate with the aim of improving the hardness and wear properties by laser cladding technique using a Rofin Sinar 4 kW Nd: YAG laser. Wear investigations were carried out with the aid of three body abrasion tester. The resultant microstructure show homogeneous distribution of TiC particles free from cracks and pores. Multiple track deposited systems with 50% overlap revealed micro-hardness increase from 357.3 HV0.1for the substrate reaching a peak as high as 922.2 HV0.1 for 60%Ti + 40%TiC and the least 665.3 HV0.1 for 80%Ti + 20%TiC MMCs. The wear resistance of the materials improved significantly, indicating a fifteen-fold wear rate reduction due to the proper distribution of ceramic particles thereby forming interstitial carbides as revealed by the X-ray diffraction spectrum.

  7. Bulletin of Materials Science | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science. REGINA C SO. Articles written in Bulletin of Materials Science. Volume 40 Issue 6 October 2017 pp 1179-1187. Preparation, characterization of chitosan/bamboo charcoal/poly(methacrylate) composite beads · DOROTHY CAMINOS-PERUELO WEI-CHIEH WANG ...

  8. ming-fa hsieh

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science. MING-FA HSIEH. Articles written in Bulletin of Materials Science. Volume 40 Issue 6 October 2017 pp 1179-1187. Preparation, characterization of chitosan/bamboo charcoal/poly(methacrylate) composite beads · DOROTHY CAMINOS-PERUELO WEI-CHIEH WANG ...

  9. Electrospun TiO{sub 2} nanofibers decorated Ti substrate for biomedical application

    Energy Technology Data Exchange (ETDEWEB)

    Dumitriu, Cristina [Åbo Akademi University, Process Chemistry Centre, Laboratory of Analytical Chemistry, Biskopsgatan 8, Åbo-Turku FI-20500 (Finland); Politehnica University Bucharest, Faculty of Applied Chemistry and Materials Science, Department of General Chemistry, 1-7 Polizu, Bucharest Ro-011061 (Romania); Stoian, Andrei Bogdan [Politehnica University Bucharest, Faculty of Applied Chemistry and Materials Science, Department of General Chemistry, 1-7 Polizu, Bucharest Ro-011061 (Romania); Titorencu, Irina; Pruna, Vasile; Jinga, Victor V. [Institute of Cellular Biology and Pathology “Nicolae Simionescu”, 8 B. P. Hasdeu, district 5, Bucharest Ro-050568 (Romania); Latonen, Rose-Marie; Bobacka, Johan [Åbo Akademi University, Process Chemistry Centre, Laboratory of Analytical Chemistry, Biskopsgatan 8, Åbo-Turku FI-20500 (Finland); Demetrescu, Ioana, E-mail: i_demetrescu@chim.upb.ro [Politehnica University Bucharest, Faculty of Applied Chemistry and Materials Science, Department of General Chemistry, 1-7 Polizu, Bucharest Ro-011061 (Romania)

    2014-12-01

    Various TiO{sub 2} nanofibers on Ti surface have been fabricated via electrospinning and calcination. Due to different elaboration conditions the electrospun fibers have different surface feature morphologies, characterized by scanning electronic microscopy, surface roughness, and contact angle measurements. The results have indicated that the average sample diameters are between 32 and 44 nm, roughness between 61 and 416 nm, and all samples are hydrophilic. As biological evaluation, cell culture with MG63 cell line originally derived from a human osteosarcoma was performed and correlation between nanofibers elaboration, properties and cell response was established. The cell adherence and growth are more evident on Ti samples with more aligned fibers, higher roughness and strong hydrophilic character and such fibers have been elaborated with a high speed rotating cylinder collector, confirming the idea that nanostructure elaboration conditions guide the cells' growth. - Highlights: • Processing Ti surface via electrospinning and calcination leads to TiO{sub 2} nanofibers. • The TiO{sub 2} electrospun fibers on Ti have diameters between 10 and 100 nm. • Elaboration with high speed rotating cylinder collector leads to aligned fibers. • The samples have roughness between 61 and 416 nm and all of them are hydrophilic. • Cell adherence and viability is more evident on Ti samples with aligned fibers.

  10. Microstructural evolution and mechanical properties of Ti3SiC2-TiC composites

    International Nuclear Information System (INIS)

    Tian, WuBian; Sun, ZhengMing; Hashimoto, Hitoshi; Du, YuLei

    2010-01-01

    Ti 3 SiC 2 -TiC composites were fabricated by pulse discharge sintering technique using three different sets of powder mixtures, i.e. Ti/Si/TiC (TC30), Ti/Si/C/TiC (SI30) and Ti/Si/C (TSC30). Based on X-ray diffraction (XRD) analysis and microstructural observations, starting powder reactants were found to have little effect on phase content but strong influence on the microstructure in terms of phase distribution. The phase distribution mainly relies on the heat released from reaction and the liquid phase content formed during sintering. The mechanical properties of the fabricated dense samples demonstrate that more homogeneous phase distribution, available by choosing the starting reactants of SI30, results in higher flexural strength, whereas the Vickers hardness is almost independent of the microstructure. The enhanced flexural strength in sample SI30 sintered at 1400 o C is mainly attributed to the homogeneous TiC distribution in the microstructure.

  11. Experimental and theoretical studies on X-ray induced secondary electron yields in Ti and TiO2

    International Nuclear Information System (INIS)

    Iyasu, Takeshi; Tamura, Keiji; Shimizu, Ryuichi; Vlaicu, Mihai Aurel; Yoshikawa, Hideki

    2006-01-01

    Generation of X-ray induced secondary electrons in Ti and TiO 2 was studied from both experimental and theoretical approaches, using X-ray photoelectron spectroscopy (XPS) attached to a synchrotron radiation facility and Monte Carlo simulation, respectively. The experiment revealed that the yields of secondary electrons induced by X-rays (electrons/photon) at photon energies to 4950 and 5000eV for Ti and TiO 2 are δ Ti (4950eV)=0.002 and δ Ti (5000eV)=0.014 while those for TiO 2 are δ TiO 2 (4950eV)=0.003 and δ TiO 2 (5000eV)=0.018. A novel approach to obtain the escape depth of secondary electrons has been proposed and applied to Ti and TiO 2 . The approach agreed very well with the experimental data reported so far. The Monte Carlo simulation predicted; δ Ti * (4950eV)=0.002 and δ Ti * (5000eV)=0.011 while δ TiO 2 * (4950eV)=0.003 and δ TiO 2 * (5000eV)=0.015. An experimental examination on the contribution of X-ray induced secondary electrons to photocatalysis in TiO 2 has also been proposed

  12. Microstructure and high temperature oxidation resistance of in-situ synthesized TiN/Ti_3Al intermetallic composite coatings on Ti6Al4V alloy by laser cladding process

    International Nuclear Information System (INIS)

    Liu, Hongxi; Zhang, Xiaowei; Jiang, Yehua; Zhou, Rong

    2016-01-01

    High temperature anti-oxidation TiN/Ti_3Al intermetallic composite coatings were fabricated with the powder and AlN powder on Ti6Al4V titanium alloy surface by 6 kW transverse-flow CO_2 laser apparatus. The chemical composition, morphology and microstructure of the TiN/Ti_3Al composite coatings were characterized by optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersive spectrometer (EDS). In order to evaluate the high temperature oxidation resistance of TiN/Ti_3Al coating, the isothermal oxidation test was performed in a high temperature resistance furnace at 600 °C and 800 °C, respectively. The result shows that the composite coating has a rapidly solidified fine microstructure consisting of TiN primary phase (granular-like, flake-like or dendrites), with an even distribution in Ti_3Al matrix. It indicates that a physical and chemical reaction between Ti powder and AlN powder has completely occurred under the laser irradiation condition. In addition, the microhardness of the TiN/Ti3Al intermetallic composite coating is 3.4 times higher than that of the Ti6Al4V alloy substrate and reaches 844 HV_0_._2. The high temperature oxidation behavior test reveals that the high temperature oxidation resistance of TiN/Ti_3Al composite coating is much better than that of titanium alloy substrate. The excellent high temperature oxidation resistance of TiN/Ti_3Al intermetallic composite coating is attributed to the formation of reinforced phases TiN, Al_2O_3 and TiO_2. The laser cladding TiN/Ti_3Al intermetallic composite coating is anticipated to be a promising high temperature oxidation resistance coating for Ti6Al4V alloy. - Highlights: • In-situ TiN/Ti_3Al composite coating was synthesized on Ti6Al4V alloy by laser cladding. • The influence of Ti and AlN molar ratio on the microstructure of the coating was studied. • The TiN/Ti_3Al intermetallic coating is mainly composed of α-Ti, TiN and Ti_3Al phases. • The

  13. Sputter deposition and characterisation of hard wear-resistant Ti/TiN multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Simmonds, M.C.; Swygenhoven, H. van [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-09-01

    Multilayered Ti/TiN thin films have been synthesized by magnetron sputter deposition. Alternating layers of Ti and TiN with layer thickness in the 5-50 nm range are sequentially deposited. The structure of the films have been characterised by atomic force microscopy (AFM), X-ray diffraction and reflection and Auger depth profiling. The mechanical properties have been investigated using pin-on-disc wear rate testing, nanoindentation determination of hardness and micro scratch testing. (author) 1 fig., 3 refs.

  14. Orthorhombic strontium titanate in BaTiO sub 3 -SrTiO sub 3 superlattices

    CERN Document Server

    Rios, S; Jiang, A Q; Scott, J F; Lü, H; Chen, Z

    2003-01-01

    It has been suggested by several authors that SrTiO sub 3 layers in SrTiO sub 3 -BaTiO sub 3 superlattices should be tetragonal and ferroelectric at ambient temperatures, like the BaTiO sub 3 layers, rather than cubic, as in bulk SrTiO sub 3 , and that free-energy minimization requires continuity of the polarization direction. A recent ab initio calculation constrained solutions to this structure. Surprisingly, our x-ray study shows that the SrTiO sub 3 layers are orthorhombic with 0.03% in-plane strain, with the BaTiO sub 3 c-axis matching the SrTiO sub 3 a- and b-axis better than the c-axis; strain energy overcomes the cost in electrostatic energy. (letter to the editor)

  15. Visible Light Photoelectrochemical Properties of N-Doped TiO2 Nanorod Arrays from TiN

    Directory of Open Access Journals (Sweden)

    Zheng Xie

    2013-01-01

    Full Text Available N-doped TiO2 nanorod arrays (NRAs were prepared by annealing the TiN nanorod arrays (NRAs which were deposited by using oblique angle deposition (OAD technique. The TiN NRAs were annealed at 330°C for different times (5, 15, 30, 60, and 120 min. The band gaps of annealed TiN NRAs (i.e., N-doped TiO2 NRAs show a significant variance with annealing time, and can be controlled readily by varying annealing time. All of the N-doped TiO2 NRAs exhibit an enhancement in photocurrent intensity in visible light compared with that of pure TiO2 and TiN, and the one annealed for 15 min shows the maximum photocurrent intensity owning to the optimal N dopant concentration. The results show that the N-doped TiO2 NRAs, of which the band gap can be tuned easily, are a very promising material for application in photocatalysis.

  16. Fracture toughness of Ti-Al3Ti-Al-Al3Ti laminate composites under static and cyclic loading conditions

    Science.gov (United States)

    Patselov, A. M.; Gladkovskii, S. V.; Lavrikov, R. D.; Kamantsev, I. S.

    2015-10-01

    The static and cyclic fracture toughnesses of a Ti-Al3Ti-Al-Al3Ti laminate composite material containing at most 15 vol % intermetallic compound are studied. Composite specimens are prepared by terminating reaction sintering of titanium and aluminum foils under pressure. The fracture of the titanium layers is quasi-cleavage during cyclic crack growth and is ductile during subsequent static loading.

  17. TiO2/Pt/TiO2 Sandwich Nanostructures: Towards Alcohol Sensing and UV Irradiation-Assisted Recovery

    Directory of Open Access Journals (Sweden)

    Rungroj Maolanon

    2017-01-01

    Full Text Available The TiO2/Pt/TiO2 sandwich nanostructures were synthesized by RF magnetron sputtering and demonstrated as an alcohol sensor at room-temperature operation with a fast recovery by UV irradiation. The TiO2/Pt/TiO2 layers on SiO2/Si substrate were confirmed by Auger electron spectroscopy with the interdiffusion of each layer. The TiO2/Pt/TiO2 layers on printed circuit board show the superior sensor response to alcohol in terms of the sensitivity and stability compared to the nonsandwich structure, that is, the only Pt layer or the TiO2/Pt structures. Moreover, the recovery time of the TiO2/Pt/TiO2 was improved by UV irradiation-assisted recovery. The optimum TiO2/Pt/TiO2 with thicknesses of the undermost TiO2 layer, a Pt layer, and the topmost TiO2 layer being 50 nm, 6 nm, and 5 nm, respectively, showed the highest response to ethanol down to 10 ppm. Additionally, TiO2/Pt/TiO2 shows an excellent sensing stability and exhibits different sensing selectivity among ethanol, methanol, and 2-propanol. The sensing mechanism could be attributed to the change of Pt work function during vapor adsorption. The TiO2 layer plays an important role in UV-assisted recovery by photocatalytic activity and the topmost TiO2 acts as protective layer for Pt.

  18. Synthesis and Isolation of the Titanium-Scandium Endohedral Fullerenes-Sc2 TiC@Ih -C80 , Sc2 TiC@D5h -C80 and Sc2 TiC2 @Ih -C80 : Metal Size Tuning of the Ti(IV) /Ti(III) Redox Potentials.

    Science.gov (United States)

    Junghans, Katrin; Ghiassi, Kamran B; Samoylova, Nataliya A; Deng, Qingming; Rosenkranz, Marco; Olmstead, Marilyn M; Balch, Alan L; Popov, Alexey A

    2016-09-05

    The formation of endohedral metallofullerenes (EMFs) in an electric arc is reported for the mixed-metal Sc-Ti system utilizing methane as a reactive gas. Comparison of these results with those from the Sc/CH4 and Ti/CH4 systems as well as syntheses without methane revealed a strong mutual influence of all key components on the product distribution. Whereas a methane atmosphere alone suppresses the formation of empty cage fullerenes, the Ti/CH4 system forms mainly empty cage fullerenes. In contrast, the main fullerene products in the Sc/CH4 system are Sc4 C2 @C80 (the most abundant EMF from this synthesis), Sc3 C2 @C80 , isomers of Sc2 C2 @C82 , and the family Sc2 C2 n (2 n=74, 76, 82, 86, 90, etc.), as well as Sc3 CH@C80 . The Sc-Ti/CH4 system produces the mixed-metal Sc2 TiC@C2 n (2 n=68, 78, 80) and Sc2 TiC2 @C2 n (2 n=80) clusterfullerene families. The molecular structures of the new, transition-metal-containing endohedral fullerenes, Sc2 TiC@Ih -C80 , Sc2 TiC@D5h -C80 , and Sc2 TiC2 @Ih -C80 , were characterized by NMR spectroscopy. The structure of Sc2 TiC@Ih -C80 was also determined by single-crystal X-ray diffraction, which demonstrated the presence of a short Ti=C double bond. Both Sc2 TiC- and Sc2 TiC2 -containing clusterfullerenes have Ti-localized LUMOs. Encapsulation of the redox-active Ti ion inside the fullerene cage enables analysis of the cluster-cage strain in the endohedral fullerenes through electrochemical measurements. © 2016 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  19. Pt hierarchical structure catalysts on BaTiO{sub 3}/Ti electrode for methanol and ethanol electrooxidations

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Chenguo; He, Xiaoshan; Xia, Chuanhui [Department of Applied Physics, Chongqing University, Chongqing 400044 (China)

    2010-03-15

    Electrooxidations of methanol and ethanol have been investigated on different Pt catalytic titanium-supported electrodes in both acidic and alkaline media using cyclic voltammetry. BaTiO{sub 3} is used for the first time to make a nanoscaled roughness on the surface of Ti foil in order to effectively deposit Pt hierarchical structure and block foulness in solution reactions. The morphology of BaTiO{sub 3} nanocube on Ti foil, Pt catalysts deposited on BaTiO{sub 3}/Ti and Ti foil electrodes are characterized by field emission scanning electron microscopy. The results indicate that Pt nanoflowers can be effectively grown on the Ti foil covered with 1 {mu}m layer of BaTiO{sub 3} nanocubes and the catalytic oxidation behaviors to methanol and ethanol are much better than those of the Pt/Ti electrode as Pt nanoparticles can hardly be deposited on the smooth surface of the Ti foil. The Pt/BaTiO{sub 3}/Ti electrode could be adopted as excellent catalytic anode in fuel cells. (author)

  20. Critical Temperature tuning of Ti/TiN multilayer films suitable for low temperature detectors

    OpenAIRE

    Giachero, A.; Day, P.; Falferi, P.; Faverzani, M.; Ferri, E.; Giordano, C.; Marghesin, B.; Mattedi, F.; Mezzena, R.; Nizzolo, R.; Nucciotti, A.

    2013-01-01

    We present our current progress on the design and test of Ti/TiN Multilayer for use in Kinetic Inductance Detectors (KIDs). Sensors based on sub-stoichiometric TiN film are commonly used in several applications. However, it is difficult to control the targeted critical temperature $T_C$, to maintain precise control of the nitrogen incorporation process and to obtain a production uniformity. To avoid these problems we investigated multilayer Ti/TiN films that show a high uniformity coupled wit...

  1. Electrocatalytic activity of Pd-loaded Ti/TiO2 nanotubes cathode for TCE reduction in groundwater.

    Science.gov (United States)

    Xie, Wenjing; Yuan, Songhu; Mao, Xuhui; Hu, Wei; Liao, Peng; Tong, Man; Alshawabkeh, Akram N

    2013-07-01

    A novel cathode, Pd loaded Ti/TiO2 nanotubes (Pd-Ti/TiO2NTs), is synthesized for the electrocatalytic reduction of trichloroethylene (TCE) in groundwater. Pd nanoparticles are successfully loaded on TiO2 nanotubes which grow on Ti plate via anodization. Using Pd-Ti/TiO2NTs as the cathode in an undivided electrolytic cell, TCE is efficiently and quantitatively transformed to ethane. Under conditions of 100 mA and pH 7, the removal efficiency of TCE (21 mg/L) is up to 91% within 120 min, following pseudo-first-order kinetics with the rate constant of 0.019 min(-1). Reduction rates increase from 0.007 to 0.019 min(-1) with increasing the current from 20 to 100 mA, slightly decrease in the presence of 10 mM chloride or bicarbonate, and decline with increasing the concentrations of sulfite or sulfide. O2 generated at the anode slightly influences TCE reduction. At low currents, TCE is mainly reduced by direct electron transfer on the Pd-Ti/TiO2NT cathode. However, the contribution of Pd-catalytic hydrodechlorination, an indirect reduction mechanism, becomes significant with increasing the current. Compared with other common cathodes, i.e., Ti-based mixed metal oxides, graphite and Pd/Ti, Pd-Ti/TiO2NTs cathode shows superior performance for TCE reduction. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. Grotrian diagrams for highly ionized titanium Ti V-Ti XXII

    International Nuclear Information System (INIS)

    Mori, Kazuo

    1982-06-01

    Grotrian diagrams of Ti V-Ti XXII have been prepared. Data of wavelengths, energy levels, oscillator strengths and transition probabilities are updated for diagnostics of high temperature plasmas, and tabulated with references. (author)

  3. Mechanical properties of heat treated and worn PVD, TiN, (Ti, Al)N, (Ti, Nb)N and Ti(C, N) coatings as measured by nanoindentation

    Energy Technology Data Exchange (ETDEWEB)

    Vancoille, E.; Celis, J.P.; Roos, J.R. (Dept. of Metallurgy and Materials Engineering, Katholieke Univ. Leuven, Heverlee (Belgium))

    1993-03-15

    Steered arc ion plated TiN, (Ti[sub 50], Al[sub 50])N, (Ti[sub 85], Nb[sub 15])N and Ti(C[sub 60], N[sub 40]) coatings were heat treated in an inert argon atmosphere at temperatures up to 900degC. The hardness, Young's modulus and plasticity of the coatings were measured with nanoindentation after heating. As the coatings were annealed at higher temperatures, the hardness decreased and the plasticity increased. X-ray diffraction of the coatings showed that this corresponds to a decrease in internal stress and a change of crystallographic texture. The nanohardness of the cutting edge of coated drills was also measured after these were used in AISI 4140 steel. Scanning electron microscopy demonstrated the presence of a silicate layer located near the cutting edge of (Ti[sub 85], Nb[sub 15])N coated drills. Nanoindentation showed that the mechanical signature of the surface film further away from the cutting edge corresponded to a heat-treated coating covered with an oxide layer. (orig.).

  4. Fabrication of TiN/AlN/TiN tunnel junctions

    Energy Technology Data Exchange (ETDEWEB)

    Nakayama, Takeru; Naruse, Masato; Myoren, Hiroaki; Taino, Tohru, E-mail: taino@mail.saitama-u.ac.jp

    2016-11-15

    Highlights: • We have fabricated TiN/AlN/TiN tunnel junctions with an epitaxial layer. • TiN and AlN films were deposited by dc and rf magnetron sputtering at ambient substrate temperatures. • The junctions have a V{sub g} = 1.1 mV, J{sub c} = 0.24 A/cm{sup 2}, R{sub sg}/R{sub n} of 7.2, and low subgap leakage current of 180 nA. - Abstract: We have fabricated TiN/AlN/TiN tunnel junctions with an epitaxial layer. The critical temperature of TiN can be changed in the range from 0.5 to 5.0 K. Therefore, it is easy to set 5.0 K as the target critical temperature. When a Superconducting Tunnel Junction (STJ) is operated as a photon detector, it is necessary to cool it to within 0.1 K of the critical temperature in consideration of the noise of the thermally stimulated currents. Because 0.3 K was desirable, as for the manufacture of general purpose photon detectors, the critical temperature 5.0 K. TiN and AlN films were deposited by dc and rf magnetron sputtering in a load-lock sputtering system at ambient substrate temperatures. The junctions have a gap voltage of V{sub g} = 1.1 mV, and critical current density of J{sub c} = 0.24 A/cm{sup 2}, and R{sub sg}/R{sub n} of 7.2, and low subgap leakage current (I{sub sub}@ 500 µV = 180 nA). We report our experiment system, the manufacture method and the junction properties in this paper.

  5. Air stability and magnetic properties of GdN, TiN, and (Gd,Ti)N nanoparticles

    International Nuclear Information System (INIS)

    Si Pingzhan; Choi, C. J.; Tegus, O.; Brueck, E.; Geng, D. Y.; Zhang, Z. D.

    2008-01-01

    GdN, TiN, and (Gd,Ti)N nanoparticles were prepared by arc evaporating Gd, Ti, and Gd-Ti alloys in N 2 , respectively. Most of these nanoparticles show narrow size distribution with average diameter of 20 nm. Shell/core structure was observed in the (Gd,Ti)N nanoparticles, in which the shell was formed by surface reaction with air. (Gd,Ti)N nanoparticles are more stable than GdN nanoparticles in air due partially to the formation of the protective shell. The Curie temperature of GdN nanoparticles is lower than that of the bulk GdN. Both GdN and (Gd, Ti)N nanoparticles are difficult to reach magnetic saturation and show zero coercivity

  6. Effect of Mo2C content on the properties of TiC/TiB2 base cermets

    International Nuclear Information System (INIS)

    Takagi, Ken-ichi; Osada, Ken; Koike, Wataru; Fujima, Takuya

    2009-01-01

    The effects of Mo 2 C content on the microstructure and mechanical properties of TiC/TiB 2 base cermets were studied using the model cermets with the compositions of TiC/TiB 2 -(11-17)Mo 2 C-24Ni (mass%). TiC and TiB 2 ratio is set to molar ratio of 59:41 that is near quasi-eutectic composition. As a result, both transverse rupture strength and hardness of the cermets showed maxima for the cermet containing 13% Mo 2 C. The cermet achieved remarkable microstructural refinement and still maintained characteristic core-rim structure of the TiC base cermets. TiC/TiB 2 cermets, in addition to TiCN base cermets, are a good alternative material to cemented carbides.

  7. Chemically synthesized TiO2 and PANI/TiO2 thin films for ethanol sensing applications

    Science.gov (United States)

    Gawri, Isha; Ridhi, R.; Singh, K. P.; Tripathi, S. K.

    2018-02-01

    Ethanol sensing properties of chemically synthesized titanium dioxide (TiO2) and polyaniline/titanium dioxide nanocomposites (PANI/TiO2) had been performed at room temperature. In-situ oxidative polymerization process had been employed with aniline as a monomer in presence of anatase titanium dioxide nanoparticles. The prepared samples were structurally and morphologically characterized by x-ray diffraction, fourier transform infrared spectra, high resolution-transmission electron microscopy and field emission-scanning electron microscopy. The crystallinity of PANI/TiO2 nanocomposite was revealed by XRD and FTIR spectra confirmed the presence of chemical bonding between the polymer chains and metal oxide nanoparticles. HR-TEM micrographs depicted that TiO2 particles were embedded in polymer matrix, which provides an advantage over pure TiO2 nanoparticles in efficient adsorption of vapours. These images also revealed that the TiO2 nanoparticles were irregular in shape with size around 17 nm. FE-SEM studies revealed that in the porous structure of PANI/TiO2 film, the intercalation of TiO2 in PANI chains provides an advantage over pure TiO2 film for uniform interaction with ethanol vapors. The sensitivity values of prepared samples were examined towards ethanol vapours at room temperature. The PANI/TiO2 nanocomposite exhibited better sensing response and faster response-recovery examined at different ethanol concentrations ranging from 5 ppm to 20 ppm in comparison to pure TiO2 nanoparticles. The increase in vapour sensing of PANI/TiO2 sensing film as compared to pure TiO2 film had been explained in detail with the help of gas sensing mechanism of TiO2 and PANI/TiO2. This provides strong evidence that gas sensing properties of TiO2 had been considerably improved and enhanced with the addition of polymer matrix.

  8. Fabrication of mesoporus TiO_2 from TiOSO_4 from leached ilmenite

    International Nuclear Information System (INIS)

    Wahyuningsih S; Ramelan AH; Rinawati L; Munifa RMI; Saputri LNMZ; Hanif QA; Pranata HP; Ismoyo YA

    2016-01-01

    The fabrication of mesoporous TiO_2 from TiOSO_4 precursor through roasted process, leaching, and homogeneous hydrolysis of ilmenite had been done. Analysis of X-ray Diffraction (XRD) showed the characteristics of ilmenite, hematite and rutile. After roasting the mineral ilmenite with the addition of Na_2S at a temperature of 800°C the XRD characterization showed peaks characteristic for hematite, TiO_2 anatase, TiO_2 rutile, Na_2SO_4, NaFeS_2, and NaFeO_2. Leaching processes of roasted ilmenite which maintained with an addition of strong acid H_2SO_4 6; 7.2; 9; 12, and 18 N were obtained TiOSO_4 filtrate. The results indicated that the more concentration of H_2SO_4 the more solubility of ilmenite, where optimum solubility was achieved when H_2SO_4 concentration was 12 N. The fabrication of mesoporous TiO_2 from TiOSO_4 was conducted with homogeneous hydrolysis method used urea and surfactant template F-127. XRD characterization results indicated the dominant peak of TiO_2 anatase. Crystallite size of 3.2 nm was obtained and the results of Scanning Electron Microscopy (SEM) showed that the presence of urea and surfactant be able to arrange porosity. (author)

  9. Microstructure and high-temperature oxidation resistance of TiN/Ti3Al intermetallic matrix composite coatings on Ti6Al4V alloy surface by laser cladding

    Science.gov (United States)

    Zhang, Xiaowei; Liu, Hongxi; Wang, Chuanqi; Zeng, Weihua; Jiang, Yehua

    2010-11-01

    A high-temperature oxidation resistant TiN embedded in Ti3Al intermetallic matrix composite coating was fabricated on titanium alloy Ti6Al4V surface by 6kW transverse-flow CO2 laser apparatus. The composition, morphology and microstructure of the laser clad TiN/Ti3Al intermetallic matrix composite coating were characterized by optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersive spectrometer (EDS). In order to evaluate the high-temperature oxidation resistance of the composite coatings and the titanium alloy substrate, isothermal oxidation test was performed in a conventional high-temperature resistance furnace at 600°C and 800°C respectively. The result shows that the laser clad intermetallic composite coating has a rapidly solidified fine microstructure consisting of TiN primary phase (granular-like, flake-like, and dendrites), and uniformly distributed in the Ti3Al matrix. It indicates that a physical and chemical reaction between the Ti powder and AlN powder occurred completely under the laser irradiation. In addition, the microhardness of the TiN/Ti3Al intermetallic matrix composite coating is 844HV0.2, 3.4 times higher than that of the titanium alloy substrate. The high-temperature oxidation resistance test reveals that TiN/Ti3Al intermetallic matrix composite coating results in the better modification of high-temperature oxidation behavior than the titanium substrate. The excellent high-temperature oxidation resistance of the laser cladding layer is attributed to the formation of the reinforced phase TiN and Al2O3, TiO2 hybrid oxide. Therefore, the laser cladding TiN/Ti3Al intermetallic matrix composite coating is anticipated to be a promising oxidation resistance surface modification technique for Ti6Al4V alloy.

  10. Microstructural studies and wear assessments of Ti/TiC surface composite coatings on commercial pure Ti produced by titanium cored wires and TIG process

    Energy Technology Data Exchange (ETDEWEB)

    Monfared, A., E-mail: amirmonfared25@yahoo.com [Department of Materials Science and Engineering, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Kokabi, A.H.; Asgari, S. [Department of Materials Science and Engineering, Sharif University of Technology, Tehran (Iran, Islamic Republic of)

    2013-01-15

    Tungsten Inert Gas (TIG) process and titanium cored wires filled with micro size TiC particles were employed to produce surface composite coatings on commercial pure Ti substrate for wear resistance improvement. Wire drawing process was utilized to produce several cored wires from titanium strips and titanium carbide powders. Subsequently, these cored wires were melted and coated on commercial pure Ti using TIG process. This procedure was repeated at different current intensities and welding travel speeds. Composite coating tracks were found to be affected by TIG heat input. The microstructural studies using optical and scanning electron microscopy supported by X-ray diffraction showed that the surface composite coatings consisted of {alpha} Prime -Ti, spherical and dendritic TiC particles. Also, greater volume fractions of TiC particles in the coatings were found at lower heat input. A maximum microhardness value of about 1100 HV was measured which is more than 7 times higher than the substrate material. Pin-on-disk wear tests exhibited a better performance of the surface composite coatings than the untreated material which was attributed to the presence of TiC particles in the microstructure. -- Highlights: Black-Right-Pointing-Pointer Ti/TiC composite coatings were produced on the CP-Ti. Black-Right-Pointing-Pointer Titanium cored wire and TIG process were employed for production of the coatings. Black-Right-Pointing-Pointer Decreasing heat input, increased the volume fraction of TiC in the coatings. Black-Right-Pointing-Pointer The maximum microhardness obtained in the lowest heat input. Black-Right-Pointing-Pointer The wear resistance of the coatings improved due to the formation of TiC particles.

  11. Sulfide phase in the Fe-Ti-S and Fe-C-Ti-S alloys

    International Nuclear Information System (INIS)

    Malinochka, Ya.N.; Balakina, N.A.; Shmelev, Yu.S.

    1976-01-01

    The nature of the sulfide phases in Fe-Ti-S and Fe-C-Ti-S alloys was studied. The carbide and the sulfide phase were identified the aid of X-ray spectral microanalysis. It was established that for a small content of titanium and sulfur in ternary Fe-Ti-S alloys the solidification of the γ-solution on the boundaries of dendritic branches is accompanied, along with the precipitation of a sulfide rich in iron of the (Fe, Ti) S type where a small quantity of titanium is dissolved, by the formation of a titanium-bearing sulfide eutectic γ + TiS. The amount of the sulfide eutectic increases with the contents of titanium and sulfur until a purely eutectic alloy is formed. Both carbides and sulfides may be formed in the solidification of quaternary alloys Fe-C-Ti-S

  12. Friction and wear behavior of Inconel 625 with Ni3Ti, TiN, TiC-CVD coatings in an HTGR environment

    International Nuclear Information System (INIS)

    Sarosiek, A.M.; Li, C.C.

    1984-04-01

    The following conclusions apply to Inconel 625 with Ni 3 Ti, TiN, TiC-CVD coatings, tested in an HTGR environment in a temperature range between 500 and 900 0 C at a contact pressure of 3.45 MPa. The average wear rate is very small varying between 0.0 and 1.7 x 10 -4 g/m. The wear rate shows little dependence on temperature and sliding velocity, increasing slightly as the temperature increases or as the sliding velocity decreases. Damage experienced by wear areas is minimal. Stick-slip friction was observed at low sliding velocity, however the friction coefficient is low (maximum 0.63) with an average value of about 0.44. The friction coefficient shows little dependence on temperature and sliding velocity, increasing slightly as the temperature increases, or as the sliding velocity decreases. Ni 3 Ti, TiN, TiC-CVD coatings, are considered effective in minimizing friction and wear damage of Inconel 625 in an HTGR environment

  13. XPS STRUCTURE ANALYSIS OF TiN/TiC BILAYERS PRODUCED BY PULSED VACUUM ARC DISCHARGE

    Directory of Open Access Journals (Sweden)

    ELISABETH RESTREPO PARRA

    2010-01-01

    Full Text Available se crecieron bicapas de TiN/TiC sobre sustratos de acero inoxidable 304 usando un sistema de deposición física de vapor asistida por plasma en forma de arco pulsado a dos diferentes temperaturas del sustrato (50º C y150º C. Para el análisis de la composición química se empleó la técnica de la espectroscopía de fotoelectrones de rayos X (XPS. Se observó el comportamiento de las líneas Ti2p, N1s y C1s. Los análisis de energía de enlace confirmaron la conformación de TiN y TiC. Los picos C1s y Ti2p sufrieron un corrimiento a medida que se incrementó el tiempo de esputtering, revelando contaminación debido a la presencia de hidrocarburos. Además, los perfiles de profundidad de las bicapas de TiN/TiC mostraron que las películas crecidas a una temperatura de 150 ° C tienen una capa de TiN más gruesa que las muestras crecidas a 50º C. El nitrógeno se difundió en la capa de TiC y el carbón en la capa de TiN para ambas temperaturas.

  14. Uniform distribution of TiCp in TiCp/Zn-Al composites prepared by XDTM

    Institute of Scientific and Technical Information of China (English)

    王香; 马旭梁; 李庆芬; 曾松岩

    2002-01-01

    The prefabricated Al/TiC alloy with high TiC particle content was prepared by XDTM process. The uniform distribution process of TiC particles in the stationary zinc melt was studied and analyzed using self-made experimental equipment, and the model of the uniform distribution process was built. The results show that zinc diffuses into the prepared Al/TiC alloy after it is placed in the zinc melt at temperatures below the melting point of aluminum, which leads to the decrease of the liquidus temperature of Al-Zn alloy in the surface layer of Al/TiC alloy. When the liquidus temperature of Al-Zn alloy is equal to or below the temperature of zinc melt, Al-Zn alloy melts and TiC particles drop with it from the Al/TiC alloy and then transfer into the zinc melt and finally distribute uniformly in it.

  15. Effect of TiCl4 treatment on the refractive index of nanoporous TiO2 films

    Science.gov (United States)

    Lee, Jeeyoung; Lee, Myeongkyu

    2015-12-01

    We investigate the effect of TiCl4 treatment on the refractive index of a nanoporous TiO2 film. A nanoparticulate TiO2 film prepared on a glass substrate was immersed in a TiCl4 aqueous solution. The subsequent reaction of TiCl4 with H2O produces TiO2 and thus modifies the density and the refractive index of the film. With increasing TiCl4 concentration, the refractive index initially increased and then declined after being maximized (n = 2.02 at 633 nm) at 0.08 M concentration. A refractive index change as large as 0.45 could be obtained with the TiCl4 treatment, making it possible to achieve diffraction efficiency exceeding 80% in a diffraction grating-embedded TiO2 film. For high TiCl4 concentrations of 0.32 M and 0.64 M, the refractive index remained nearly unchanged. This was attributed to the limited permeability of high-viscosity TiCl4 solutions into the nanoporous films. The measured pore size distributions were in good agreement with the results of a diffraction analysis and refractive index measurement.

  16. Structure and hardness of TiAl-TiB2 composite prepared by hot isostatic pressing of mechanically alloyed powders. Mekanikaru aroingu funmatsu no HIP shoketsu ni yori sakuseishita TiAl/TiB2 fukugo zairyo no soshiki to kodo

    Energy Technology Data Exchange (ETDEWEB)

    Sato, T; Shimakage, K [Muroran Inst. of Technology, Hokkaido (Japan). Faculty of Engineering; Miyakawa, S [Muroran Inst. of Technology, Hokkaido (Japan). Graduate Student

    1992-11-20

    The practical application of Ti-Al system intermetallic compounds is expected as an advanced light heat resistant material. TiAl group out of them, as for the specific strength, has an equivalent maximum working temperature as that of the nickel base alloy, which is utilized as a turbine material for the current aircraft, and moreover it is also said that it is superior in the creep and rupture properties to the latter. In this study, by mechanical alloying (MA) of each mixed powder of Ti-Al and Ti-B, by suing heptane as a grinding aid, each MA powder of the amorphous TiAl containing carbon and extremely fine compound TiB2 were prepared, and subsequently the true density sintering by the hot isostatic pressing (HIP) was performed, and by doing these, the preparation of TiAl/TiB2 system composite material with a high composite ratio of TiO2 was tried. Consequently, by the MA treatment of the mixed powder of Ti and B for more than 50 hours, the compound powder of TiB2 mixed with TiB could be prepared, and its hardness has shown the maximum value Hmv=l200 with a composition of TiAl/25 mol % TiB2. 14 refs., 10 figs., 2 tabs.

  17. TiO2-TiO2 composite resistive humidity sensor: ethanol crosssensitivity

    International Nuclear Information System (INIS)

    Ghalamboran, Milad; Saedi, Yasin

    2016-01-01

    The fabrication method and characterization results of a TiO 2 -TiO 2 composite bead used for humidity sensing along with its negative cross-sensitivity to ethanol vapor are reported. The bead shaped resistive sample sensors are fabricated by the drop-casting of a TiO 2 slurry on two Pt wire segments. The dried bead is pre-fired at 750°C and subsequently impregnated with a Ti-based sol. The sample is ready for characterization after a thermal annealing at 600°C in air. Structurally, the bead is a composite of the micron-sized TiO 2 crystallites embedded in a matrix of nanometric TiO 2 particle aggregates. The performance of the beads as resistive humidity sensors is recorded at room temperature in standard humidity level chambers. Results evince the wide dynamic range of the sensors fabricated in the low relative humidity range. While the sensor conductance is not sensitive to ethanol vapor in dry air, in humid air, sensor's responses are negatively affected by the contaminant. (paper)

  18. Wettability between TiN,TiC Containing Carbon Composite Refractory and Molten Slag or Hot Metal

    Institute of Scientific and Technical Information of China (English)

    SHIYue-xun; LIYingand; 等

    1994-01-01

    In order to develop a new-type TiC-TiN containing carbon composite refractory so as to improve the service life of blast furnace hearth,the wettability between the carbon refractory and molten slag or metal has been mea-sured.It was indicated that the carbon refractory is wet-ted by slag(θ≤90°) when(TiC+TiN)>33.52%,The effects of TiN or TiC on wetting behavior are basi-cally identical.When the amount of TiC in the carbon com-posite refractory is greater than 60% it will be wetted by hot metal;therefore,the carbon composite refractory will be wetted by slag but not permeated by hot metal when the amount of TiC is restricted.

  19. Hydrothermal–galvanic couple synthesis of directionally oriented BaTiO3 thin films on TiN-coated substrates

    International Nuclear Information System (INIS)

    Yang, Chia-Jung; Tsai, Di-You; Chan, Pei-Hsuan; Wu, Chu-Tsun; Lu, Fu-Hsing

    2013-01-01

    BaTiO 3 films were synthesized on TiN-coated Si substrate below 100 °C by a hydrothermal–galvanic couple technique in barium contained alkaline solutions. X-ray diffraction and electron backscatter diffraction results show that the BaTiO 3 thin films were directionally oriented grown on the TiN/Si substrates, i.e., (111) BaTiO 3 over (111) TiN. The surface morphologies revealed that BaTiO 3 nucleated and grew over the TiN surface with a single layer. From kinetic analyses, the growth rates of BaTiO 3 films prepared by the hydrothermal–galvanic couple technique were faster than a hydrothermal method. The galvanic effects were confirmed by investigating the induced currents and energies. The galvanic currents were generated and controlled by both the dissolution of TiN and the formation of BaTiO 3 . The output electric energies increased rapidly with the reaction time and leveled off at the full coverage of BaTiO 3 . - Highlights: • Cubic BaTiO 3 films are synthesized by a hydrothermal–galvanic couple method (HT–GC). • Growth rates of BaTiO 3 films made by HT–GC are faster than a hydrothermal method. • BaTiO 3 films are directionally oriented grown on the TiN/Si substrates. • Galvanic currents are controlled by dissolution of TiN and formation of BaTiO 3

  20. Revision of the Ge–Ti phase diagram and structural stability of the new phase Ge4Ti5

    International Nuclear Information System (INIS)

    Bittner, Roland W.; Colinet, Catherine; Tedenac, Jean-Claude; Richter, Klaus W.

    2013-01-01

    Highlights: •New compound Ge 4 Ti 5 found by experiments and by DFT ground state calculations. •Enthalpies of formation calculated for different Ge–Ti compounds. •Modifications of the Ge–Ti phase diagram suggested. -- Abstract: The binary phase diagram Ge–Ti was investigated experimentally by powder X-ray diffraction, scanning electron microscopy including EDX analysis, and differential thermal analysis. Total energies of the compounds GeTi 3 , GeTi 2 , Ge 3 Ti 5 , Ge 4 Ti 5 , Ge 5 Ti 6 , GeTi and Ge 2 Ti were calculated for various structure types employing electronic density-functional theory (DFT). Experimental studies as well as electronic calculations show the existence of a new phase Ge 4 Ti 5 (Ge 4 Sm 5 -type, oP36, Pnma) which is formed in a solid state reaction Ge 3 Ti 5 + Ge 5 Ti 6 = Ge 4 Ti 5 . In addition, a significant homogeneity range was observed for the compound Ge 3 Ti 5 and the composition of the liquid phase in the eutectic reaction L = Ge + Ge 2 Ti was found to be at significant higher Ge-content (97.5 at.% Ge) than reported in previous studies. Based on these new results, a modified phase diagram Ge–Ti is suggested. The zero-temperature lattice parameters and the formation enthalpies determined by DTF calculations were found to be in good agreement with experimental data

  1. A united refinement technology for commercial pure Al by Al-10Ti and Al-Ti-C master alloys

    International Nuclear Information System (INIS)

    Ma Xiaoguang; Liu Xiangfa; Ding Haimin

    2009-01-01

    Because flake-like TiAl 3 particles in Al-Ti-C master alloys prepared in a melt reaction method dissolve slowly when they are added into Al melt at 720 deg. C, Ti atoms cannot be released rapidly to play the assistant role of grain refinement, leading to a poor refinement efficiency of Al-Ti-C master alloys. A united refinement technology by Al-10Ti and Al-Ti-C master alloys was put forward in this paper. The rational combination of fine blocky TiAl 3 particles in Al-10Ti and TiC particles in Al-Ti-C can improve the nucleation rate of α-Al. It not only improves the grain refinement efficiency of Al-Ti-C master alloys, but also reduces the consumption

  2. Microstructure and high temperature oxidation resistance of in-situ synthesized TiN/Ti{sub 3}Al intermetallic composite coatings on Ti6Al4V alloy by laser cladding process

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Hongxi, E-mail: piiiliuhx@sina.com; Zhang, Xiaowei; Jiang, Yehua; Zhou, Rong

    2016-06-15

    High temperature anti-oxidation TiN/Ti{sub 3}Al intermetallic composite coatings were fabricated with the powder and AlN powder on Ti6Al4V titanium alloy surface by 6 kW transverse-flow CO{sub 2} laser apparatus. The chemical composition, morphology and microstructure of the TiN/Ti{sub 3}Al composite coatings were characterized by optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersive spectrometer (EDS). In order to evaluate the high temperature oxidation resistance of TiN/Ti{sub 3}Al coating, the isothermal oxidation test was performed in a high temperature resistance furnace at 600 °C and 800 °C, respectively. The result shows that the composite coating has a rapidly solidified fine microstructure consisting of TiN primary phase (granular-like, flake-like or dendrites), with an even distribution in Ti{sub 3}Al matrix. It indicates that a physical and chemical reaction between Ti powder and AlN powder has completely occurred under the laser irradiation condition. In addition, the microhardness of the TiN/Ti3Al intermetallic composite coating is 3.4 times higher than that of the Ti6Al4V alloy substrate and reaches 844 HV{sub 0.2}. The high temperature oxidation behavior test reveals that the high temperature oxidation resistance of TiN/Ti{sub 3}Al composite coating is much better than that of titanium alloy substrate. The excellent high temperature oxidation resistance of TiN/Ti{sub 3}Al intermetallic composite coating is attributed to the formation of reinforced phases TiN, Al{sub 2}O{sub 3} and TiO{sub 2}. The laser cladding TiN/Ti{sub 3}Al intermetallic composite coating is anticipated to be a promising high temperature oxidation resistance coating for Ti6Al4V alloy. - Highlights: • In-situ TiN/Ti{sub 3}Al composite coating was synthesized on Ti6Al4V alloy by laser cladding. • The influence of Ti and AlN molar ratio on the microstructure of the coating was studied. • The TiN/Ti{sub 3}Al intermetallic

  3. A study of the structural stability of TiC, TiN and TiO in the pressure range up to 65 GPa using synchrotron radiation

    International Nuclear Information System (INIS)

    Noerlund Christensen, A.; Gerward, L.; Staun Olsen, J.; Steenstrup, S.

    1990-01-01

    Structural phase transformations in TiC, TiN and TiO could possibly occur at high pressure because of the non-stoichiometric nature of these compounds. The NaCl structure could then possibly transform to the CsCl structure, in which case the coordination number would increase from six to eight. This is in agreement with the general rule that the coordination number increases with pressure. The present work was undertaken in order to investigate possible structural phase transformations in TiC, TiN and TiO in the pressure range up to 65 GPa (=650 kbar). (orig.)

  4. Periodic modeling of zeolite Ti-LTA.

    Science.gov (United States)

    Hernandez-Tamargo, Carlos E; Roldan, Alberto; Ngoepe, Phuti E; de Leeuw, Nora H

    2017-08-21

    We have proposed a combination of density functional theory calculations and interatomic potential-based simulations to study the structural, electronic, and mechanical properties of pure-silica zeolite Linde Type A (LTA), as well as two titanium-doped compositions. The energetics of the titanium distribution within the zeolite framework suggest that the inclusion of a second titanium atom with configurations Ti-(Si) 0 -Ti, Ti-(Si) 1 -Ti, and Ti-(Si) 2 -Ti is more energetically favorable than the mono-substitution. Infra-red spectra have been simulated for the pure-silica LTA, the single titanium substitution, and the configurations Ti-(Si) 0 -Ti and Ti-(Si) 2 -Ti, comparing against experimental benchmarks where available. The energetics of the direct dissociation of water on these Lewis acid sites indicate that this process is only favored when two titanium atoms form a two-membered ring (2MR) sharing two hydroxy groups, Ti-(OH) 2 -Ti, which suggests that the presence of water may tune the distribution of titanium atoms within the framework of zeolite LTA. The electronic analysis indicates charge transfer from H 2 O to the Lewis acid site and hybridization of their electronic states.

  5. Effect of TiAl_3 on distribution of TiC particles in aluminum matrix and nucleation of α(Al) grain%TiAl_3对TiC粒子在铝基体中分布及α(Al)晶粒形核的影响

    Institute of Scientific and Technical Information of China (English)

    夏天东; 丁万武; 赵文军; 王晓军; 徐仰涛

    2009-01-01

    研究TiC和TiAl_3细化工业纯铝时TiAl_3的存在对TiC在铝基体中分布及α(Al)晶粒形核的影响,分析Al-Ti-C晶粒细化机制.结果表明:TiC单独作为工业纯铝的晶粒细化剂时,大量TiC被α(Al)晶粒推向树枝晶的晶界处,从而限制了TiC的异质形核作用;当TiC和TiAl_3共同作为晶粒细化剂时,在α(Al)晶粒内部出现了大量TiC粒子,大量的TiC粒子成为了α(Al)的结晶核心,并且在TiC颗粒和铝基体的界面处存在"富Ti过渡区";TiAl_3在铝熔体中分解释放出Ti原子并向TiC粒子周围偏聚,形成的"TiC/铝熔体界面富Ti过渡区" 改善了TiC与α(Al)的结构适应性,降低了TiC粒子的表面张力,促进了TiC粒子在铝熔体中的均匀分布,提高了其形核能力.%The effect of TiAl_3 on the distribution of TiC particles in aluminum matrix and nucleation of α(Al) grain was studied when the TiC and TiAl_3 refining industry aluminum, and the nucleation mechanism of Al-Ti-C grain refiner were discussed. The results show that when TiC alone is used as the nucleation phase, most of the TiC is pushed into the grain boundaries by the α(Al) dendrites and the nucleation of TiC is restricted. On the other hand, when TiC and TiAl_3 refine the industry aluminum together, most of the TiC particles are found within the α(Al) grains and nucleation occurs on TiC particles, and there is a Ti transition zone between TiC and aluminum interface. TiAl_3 releases Ti atoms in aluminum melt, Ti atoms congregate to the TiC surface, and ultimately forming TiC/aluminum interface Ti transition zone, which not only improves the structure of adaptability and wettability between TiC and Al , but also reduces the surface tension of TiC particles, which making a lot of TiC particles can be uniformly distributed in the aluminum melt, which advance α(Al) core and heterogeneous nucleation in the aluminum melt solidification.

  6. TiO2 and Cu/TiO2 Thin Films Prepared by SPT

    Directory of Open Access Journals (Sweden)

    S. S. Roy

    2015-12-01

    Full Text Available Titanium oxide (TiO2 and copper (Cu doped titanium oxide (Cu/TiO2 thin films have been prepared by spray pyrolysis technique. Titanium chloride (TiCl4 and copper acetate (Cu(CH3COO2.H2O were used as source of Ti and Cu. The doping concentration of Cu was varied from 1-10 wt. %. The X-ray diffraction studies show that TiO2 thin films are tetragonal structure and Cu/TiO2 thin films implies CuO has present with monoclinic structure. The optical properties of the TiO2 thin films have been investigated as a function of Cu-doping level. The optical transmission of the thin films was found to increase from 88 % to 94 % with the addition of Cu up to 8 % and then decreases for higher percentage of Cu doping. The optical band gap (Eg for pure TiO2 thin film is found to be 3.40 eV. Due to Cu doping, the band gap is shifted to lower energies and then increases further with increasing the concentration of Cu. The refractive index of the TiO2 thin films is found to be 2.58 and the variation of refractive index is observed due to Cu doped. The room temperature resistivity of the films decreases with increasing Cu doping and is found to be 27.50 - 23.76 W·cm. It is evident from the present study that the Cu doping promoted the thin film morphology and thereby it is aspect for various applications.

  7. Swelling and irradiation creep of neutron irradiated 316Ti and 15-15Ti steels

    International Nuclear Information System (INIS)

    Maillard, A.; Touron, H.; Seran, J.L.; Chalony, A.

    1992-01-01

    The global behavior, the swelling and irradiation creep resistances of cold worked 316Ti and 15-15Ti, two variants of austenitic steels in use as core component materials of the French fast reactors, are compared. The 15-15Ti leads to a significant improvement due to an increase in the incubation dose swelling. The same phenomena observed on 316Ti are found on 15-15Ti. All species without fuel like samples, wrappers or empty clad swell and creep less than fuel pin cladding irradiated in the same conditions. To explain the swelling difference, as for 316Ti, thermal gradient is also invoked but the irradiation creep difference is not yet clearly understood. To predict the behavior of clads it is indispensable to study the species themselves and to use specific rules. All results confirm the good behavior of 15-15Ti, the best behavior being obtained with the 1% Si doped version irradiated up to 115 dpa

  8. 钛沉积工艺制备TiN/cBN和TiC/金钢石涂层颗粒%Fabrication of TiN/cBN and TiC/diamond coated particles by titanium deposition process

    Institute of Scientific and Technical Information of China (English)

    Walid M. DAOUSH; Hee S. PARK; Soon H. HONG

    2014-01-01

    Cubic boron nitride particles coated by titanium nitride (TiN/cBN) as well as diamond particles coated by titanium carbide (TiC/diamond) were prepared by Ti molten salt deposition followed by heat-treatment process. cBN or diamond particles were mixed separately with Ti powders and molten salts (KCl, NaCl and K2TiF6). The mixture was heated at 900 °C under argon atmosphere. The produced particles were heat-treated under hydrogen at 1000 °C. The morphologies and chemical compositions of the produced particles were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD) and focused ion beam (FIB). The results show that the cBN and the diamond particles are coated by nano-sized Ti layers. By heat-treatment of the Ti/cBN and TiC/diamond coated particles under hydrogen atmosphere, the deposited Ti layers were interacted by the in-situ transformation reaction with the surfaces of cBN and diamond particles and converted to titanium compounds (TiN and TiC), respectively.%用钛熔盐沉积及热处理工艺分别制备碳化钛涂覆的立方碳化硼颗粒(TiN/cBN)及碳化钛涂覆的金刚石颗粒(TiC/金刚石)。将cBN或金刚石颗粒分别与钛粉和KCl、NaCl和K2TiF6熔盐混合。将所得混合物在Ar气氛中加热至900°C,然后在H2气氛中于1000°C进行热处理。采用扫描电镜、X射线衍射和聚焦离子束技术对所制得颗粒进行表征。结果表明:cBN和金刚石颗粒表面已覆盖了纳米钛层。对Ti/cBN和TiC/金刚石涂层颗粒进行热处理后,颗粒表面沉积的Ti层与cBN和金刚石颗粒发生了原位化学反应,分别转化为钛化合物TiN和TiC。

  9. Pure rotational spectra of TiO and TiO2 in VY Canis Majoris

    Science.gov (United States)

    Kamiński, T.; Gottlieb, C. A.; Menten, K. M.; Patel, N. A.; Young, K. H.; Brünken, S.; Müller, H. S. P.; McCarthy, M. C.; Winters, J. M.; Decin, L.

    2013-03-01

    We report the first detection of pure rotational transitions of TiO and TiO2 at (sub-)millimeter wavelengths towards the red supergiant VY CMa. A rotational temperature, Trot, of about 250 K was derived for TiO2. Although Trot was not well constrained for TiO, it is likely somewhat higher than that of TiO2. The detection of the Ti oxides confirms that they are formed in the circumstellar envelopes of cool oxygen-rich stars and may be the "seeds" of inorganic-dust formation, but alternative explanations for our observation of TiO and TiO2 in the cooler regions of the envelope cannot be ruled out at this time. The observations suggest that a significant fraction of the oxides is not converted to dust, but instead remains in the gas phase throughout the outflow. Based on observations carried out with the Submillimeter Array and IRAM Plateau de Bure Interferometer.Plateau de Bure data (FITS file) is only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/551/A113

  10. Electron microscopy investigation of the TiBAl and TiCAl grain refiner master alloys

    International Nuclear Information System (INIS)

    Cizek, P

    2006-01-01

    The present work brings a detailed statistical analysis of the microstructural characteristics and chemistry of the second phase particles present in the Al-5Ti-1B and Al- 3Ti-0.15C (wt.%) commercial grain refiner rods used in the Al casting industry. The investigation was performed using the TEM, EDS, STEM and HREM techniques. Both refiner rods contained large, blocky Al 3 Ti DO 22 particles. Borides present in the TiBAl rod, known to be main α-Al nucleation substrates, exhibited a facetted, hexagonal platelet morphology and largely represented a mixed (Ti,Al)B 2 phase, with Ti and Al contents changing continuously across the particle dimensions. There were two distinct families of small particles observed in the TiCAl rod. The coarser, facetted particles corresponded to cubic TiC crystal structure and these are believed to be major α-Al nucleation sites. The family of finer, round particles appeared to correspond to orthorhombic Al 6 Fe phase and their role in the nucleation process remains to be clarified. The results obtained may be used in optimising the grain refiner rod microstructures that would ensure improved refining performance during casting

  11. Electron microscopy investigation of the TiBAl and TiCAl grain refiner master alloys

    Energy Technology Data Exchange (ETDEWEB)

    Cizek, P [IMMPETUS, Department of Engineering Materials, University of Sheffield, Mappin Street, Sheffield S1 3JD (United Kingdom)

    2006-02-22

    The present work brings a detailed statistical analysis of the microstructural characteristics and chemistry of the second phase particles present in the Al-5Ti-1B and Al- 3Ti-0.15C (wt.%) commercial grain refiner rods used in the Al casting industry. The investigation was performed using the TEM, EDS, STEM and HREM techniques. Both refiner rods contained large, blocky Al{sub 3}Ti DO{sub 22} particles. Borides present in the TiBAl rod, known to be main {alpha}-Al nucleation substrates, exhibited a facetted, hexagonal platelet morphology and largely represented a mixed (Ti,Al)B{sub 2} phase, with Ti and Al contents changing continuously across the particle dimensions. There were two distinct families of small particles observed in the TiCAl rod. The coarser, facetted particles corresponded to cubic TiC crystal structure and these are believed to be major {alpha}-Al nucleation sites. The family of finer, round particles appeared to correspond to orthorhombic Al{sub 6}Fe phase and their role in the nucleation process remains to be clarified. The results obtained may be used in optimising the grain refiner rod microstructures that would ensure improved refining performance during casting.

  12. A united refinement technology for commercial pure Al by Al-10Ti and Al-Ti-C master alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ma Xiaoguang [Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, Jinan 250061 (China); Liu Xiangfa [Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, Jinan 250061 (China)], E-mail: xfliu@sdu.edu.cn; Ding Haimin [Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, Jinan 250061 (China)

    2009-03-05

    Because flake-like TiAl{sub 3} particles in Al-Ti-C master alloys prepared in a melt reaction method dissolve slowly when they are added into Al melt at 720 deg. C, Ti atoms cannot be released rapidly to play the assistant role of grain refinement, leading to a poor refinement efficiency of Al-Ti-C master alloys. A united refinement technology by Al-10Ti and Al-Ti-C master alloys was put forward in this paper. The rational combination of fine blocky TiAl{sub 3} particles in Al-10Ti and TiC particles in Al-Ti-C can improve the nucleation rate of {alpha}-Al. It not only improves the grain refinement efficiency of Al-Ti-C master alloys, but also reduces the consumption.

  13. Effects of O in a binary-phase TiAl-Ti3Al alloy: from site occupancy to interfacial energetics

    International Nuclear Information System (INIS)

    Wei Ye; Xu Huibin; Zhou Hongbo; Zhang Ying; Lu Guanghong

    2011-01-01

    We have investigated site occupancy and interfacial energetics of a TiAl-Ti 3 Al binary-phase system with O using a first-principles method. Oxygen is shown to energetically occupy the Ti-rich octahedral interstitial site, because O prefers to bond with Ti rather than Al. The occupancy tendency of O in TiAl alloy from high to low is α 2 -Ti 3 Al to the γ-α 2 interface and γ-TiAl. We demonstrate that O can largely affect the mechanical properties of the TiAl-Ti 3 Al system. Oxygen at the TiAl-Ti 3 Al interface reduces both the cleavage energy and the interface energy, and thus weakens the interface strength but strongly stabilizes the TiAl/Ti 3 Al interface with the O 2 molecule as a reference. Consequently, the mechanical property variation of TiAl alloy due to the presence of O not only depends on the number of TiAl/Ti 3 Al interfaces but also is related to the O concentration in the alloy.

  14. Photoelectrochemical Water Splitting Properties of Ti-Ni-Si-O Nanostructures on Ti-Ni-Si Alloy.

    Science.gov (United States)

    Li, Ting; Ding, Dongyan; Dong, Zhenbiao; Ning, Congqin

    2017-10-31

    Ti-Ni-Si-O nanostructures were successfully prepared on Ti-1Ni-5Si alloy foils via electrochemical anodization in ethylene glycol/glycerol solutions containing a small amount of water. The Ti-Ni-Si-O nanostructures were characterized by field-emission scanning electron microscopy (FE-SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and diffuse reflectance absorption spectra. Furthermore, the photoelectrochemical water splitting properties of the Ti-Ni-Si-O nanostructure films were investigated. It was found that, after anodization, three different kinds of Ti-Ni-Si-O nanostructures formed in the α-Ti phase region, Ti₂Ni phase region, and Ti₅Si₃ phase region of the alloy surface. Both the anatase and rutile phases of Ti-Ni-Si-O oxide appeared after annealing at 500 °C for 2 h. The photocurrent density obtained from the Ti-Ni-Si-O nanostructure photoanodes was 0.45 mA/cm² at 0 V (vs. Ag/AgCl) in 1 M KOH solution. The above findings make it feasible to further explore excellent photoelectrochemical properties of the nanostructure-modified surface of Ti-Ni-Si ternary alloys.

  15. Ti, Al

    Indian Academy of Sciences (India)

    In the present study, authors report on the effect that substrate bias voltage has on the microstructure and mechanical properties of (Ti, Al)N hard coatings deposited with cathodic arc evaporation (CAE) technique. The coatings were deposited from a Ti0.5Al0.5 powder metallurgical target in a reactive nitrogen atmosphere at ...

  16. Review of the Methods for Production of Spherical Ti and Ti Alloy Powder

    Science.gov (United States)

    Sun, Pei; Fang, Zhigang Zak; Zhang, Ying; Xia, Yang

    2017-10-01

    Spherical titanium alloy powder is an important raw material for near-net-shape fabrication via a powder metallurgy (PM) manufacturing route, as well as feedstock for powder injection molding, and additive manufacturing (AM). Nevertheless, the cost of Ti powder including spherical Ti alloy has been a major hurdle that prevented PM Ti from being adopted for a wide range of applications. Especially with the increasing importance of powder-bed based AM technologies, the demand for spherical Ti powder has brought renewed attention on properties and cost, as well as on powder-producing processes. The performance of Ti components manufactured from powder has a strong dependence on the quality of powder, and it is therefore crucial to understand the properties and production methods of powder. This article aims to provide a cursory review of the basic techniques of commercial and emerging methods for making spherical Ti powder. The advantages as well as limitations of different methods are discussed.

  17. Annealing Effect on Mechanical Properties of Ti-Al Alloy/Pure Ti Harmonic-Structured Composite by MM/SPS Process

    International Nuclear Information System (INIS)

    Yoshida, R; Tsuda, T; Fujiwara, H; Miyamoto, H; Ameyama, K

    2014-01-01

    The Ti-Al alloy/pure Ti harmonic-structured composite was produced by mechanical milling and spark plasma sintering process for improvement of low ductility at room temperature of Ti-Al alloy. The harmonic-structured composite with the dispersed area having coarse grained titanium and the network area having fine-grained Ti-48mol%Al alloy demonstrates high strength and high ductility at room temperature. The annealing effect of the microstructure on the mechanical properties in the Ti-Al alloy/pure Ti harmonic-structured composite are investigated. The microstructure of the Ti-Al alloy/pure Ti harmonic-structured composite annealed at 873 K, 973 K and 1073 K are maintained the Ti-Al network structure and pure Ti dispersed regions, the average grain size of pure Ti dispersed region is only coarsen by annealing. The harmonic-structured composite annealed at 873 K, 973 K and 1073 K are maintained the high hardness. The tensile results reveal that the Ti-Al alloy/pure Ti harmonic- structured composite annealed at 873 K exhibits high strength and especially high ductility

  18. Microstructure and properties of TiB2-TiB reinforced titanium matrix composite coating by laser cladding

    Science.gov (United States)

    Lin, Yinghua; Yao, Jianhua; Lei, Yongping; Fu, Hanguang; Wang, Liang

    2016-11-01

    TiB2 particle and TiB short fiber reinforced titanium matrix composite coatings were prepared utilizing in situ synthesized technique by laser cladding on the surface of Ti6Al4V alloy. Through the experiment, it was found that the surface of the single-track coatings appeared in the depression, but it can be improved by laser track overlapping. With the increase of laser power density, the amount of TiB short fiber was increased, and the distribution of TiB2 and TiB became more uniform from the top to bottom. The micro-hardness of TiB2/TiB coating showed a gradient decreasing trend, and the average micro-hardness of the coatings was two-fold higher than that of the substrate. Due to the strengthening effect of TiB2 particle and TiB short fiber, the wear volume loss of the center of the coating was approximately 30% less than that of the Ti-6Al-4V substrate, and the wear mechanism of the coating was mild fatigue particle detachment.

  19. Improved tribological properties of TiC with porous nanostructured TiO{sub 2} intermediate layer

    Energy Technology Data Exchange (ETDEWEB)

    Shanaghi, Ali, E-mail: alishanaghi@gmail.com [Surface Engineering Laboratory, Materials Engineering Department, Faculty of Engineering, Tarbiat Modares University, P.O. Box 14115-143, Tehran (Iran, Islamic Republic of); Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China); Ahangarani, Shahrokh, E-mail: sh.ahangarani@gmail.com [Advanced Materials and Renewable Energies Department, Iranian Research Organization for Science and Technology, P.O. Box 15815-3538, Tehran (Iran, Islamic Republic of); Sabour Rouhaghdam, Ali Reza, E-mail: sabour01@modares.ac.ir [Surface Engineering Laboratory, Materials Engineering Department, Faculty of Engineering, Tarbiat Modares University, P.O. Box 14115-143, Tehran (Iran, Islamic Republic of); Chu, Paul K., E-mail: paul.chu@cityu.edu.hk [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China)

    2011-12-15

    Highlights: Black-Right-Pointing-Pointer The porous TiO{sub 2} nanoparticle coating is deposited as an intermediate layer on steel. Black-Right-Pointing-Pointer A homogenous and low friction TiC nanostructure coating is deposited by plasma CVD. Black-Right-Pointing-Pointer Intermediate layer can be determined the nucleation and growth of the TiC coating. Black-Right-Pointing-Pointer The porous interlayer improves the friction and wear of the TiC nanostructure coating. - Abstract: The mismatch in the thermal expansion coefficients between TiC coatings and steel substrates and residual stress in the TiC degrade the tribological properties. In this work, a porous nanostructured TiO{sub 2} coating is deposited as an intermediate layer on hot-work steel (H{sub 11}) before final deposition of the TiC film. This intermediate layer is expected to reduce the interfacial energy, decreases the thermal mismatch between TiC and steel, and improves the tribological properties. Grazing incidence X-ray diffraction (GIXRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), atomic force microscopy (AFM), and pin-on-disk are used to study the structure as well as tribological properties such as friction, wear, and hardness. Our results reveal that the porous TiO{sub 2} interlayer improves the friction, wear, hardness, and elastic modulus of the system.

  20. Fabrication of a TiO2-P25/(TiO2-P25+TiO2 nanotubes junction for dye sensitized solar cells

    Directory of Open Access Journals (Sweden)

    Nguyen Huy Hao

    2016-08-01

    Full Text Available The dye sensitized solar cell (DSSC, which converts solar light into electric energy, is expected to be a promising renewable energy source for today's world. In this work, dye sensitized solar cells, one containing a single layer and one containing a double layer, were fabricated. In the double layer DSSC structure, the under-layer was TiO2-P25 film, and the top layer consisted of a mixture of TiO2-P25 and TiO2 nanotubes. The results indicated that the efficiency of the DSSC with the double layer structure was a significant improvement in comparison to the DSSC consisting of only a single film layer. The addition of TiO2-P25 in the top layer caused an improvement in the adsorption of dye molecules on the film rather than on the TiO2 nanotubes only. The presence of the TiO2 nanotubes together with TiO2-P25 in the top layer revealed the enhancement in harvesting the incident light and an improvement of electron transport through the film.

  1. Effect of TiB2 Pretreatment on Pt/TiB2 Catalyst Performance

    International Nuclear Information System (INIS)

    Huang, Zhen; Lin, Rui; Fan, Renjie; Fan, Qinbai; Ma, Jianxin

    2014-01-01

    Highlights: • We pretreated Titanium diboride by different acids and alkali. • We synthesis the Pt/as-pretreated TiB 2 catalysts by a colloid route. • We investigated the effects of TiB 2 Pretreatment on Pt/TiB 2 Catalyst Performance. • The BET surface area and defects on the surface have a close relationship with the deposition of Pt nanoparticles. - Abstract: Carbon support corrosion of traditional Pt/C catalyst is one of the major contributors causing poor durability of proton exchange membrane fuel cells (PEMFC). Titanium diboride (TiB 2 ) has high electrical conductivity and considerable chemical stability, which making it as a good candidate for catalyst support in PEMFC. In this work, TiB 2 was pretreated by different acid and alkali. The as-obtained samples were characterized by Ex-situ microscopy (ESM) and X-ray diffraction (XRD). The pore size distribution (PSD) was analyzed by using DFT method. The PSD shows distinct volume in mesopore regions (less than 50 nm). The TiB2 pretreated by H 2 O 2 shows the biggest BET surface area of 57 m 2 g −1 and its PSD focus on mesoporous (1.5-8 nm) region, which resulted to high dispersion and better loading of Pt particles. The Hydrogen oxidization reaction (HOR) and oxygen reduction reaction (ORR) activity was characterized by Rotating Disk Electrode (RDE). The Pt/TiB 2 prepared by H 2 O 2 -pretreated TiB 2 using the colloidal method showed better half-cell electrochemical performance. Facile synthetic for the development of Pt/TiB 2 catalysts was developed

  2. Multilayer (TiN, TiAlN) ceramic coatings for nuclear fuel cladding

    Energy Technology Data Exchange (ETDEWEB)

    Alat, Ece, E-mail: exa179@psu.edu [Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA 16802 (United States); Motta, Arthur T. [Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA 16802 (United States); Department of Mechanical and Nuclear Engineering, The Pennsylvania State University, University Park, PA 16802 (United States); Comstock, Robert J.; Partezana, Jonna M. [Westinghouse Electric Co., Beulah Rd, Pittsburgh, PA 1332 (United States); Wolfe, Douglas E. [Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA 16802 (United States); Applied Research Laboratory, The Pennsylvania State University, 119 Materials Research Building, University Park, PA 16802 (United States)

    2016-09-15

    In an attempt to develop an accident-tolerant fuel (ATF) that can delay the deleterious consequences of loss-of-coolant-accidents (LOCA), multilayer coatings were deposited onto ZIRLO{sup ®} coupon substrates by cathodic arc physical vapor deposition (CA-PVD). Coatings were composed of alternating TiN (top) and Ti{sub 1-x}Al{sub x}N (2-layer, 4-layer, 8-layer and 16-layer) layers. The minimum TiN top coating thickness and coating architecture were optimized for good corrosion and oxidation resistance. Corrosion tests were performed in static pure water at 360 °C and 18.7 MPa for up to 90 days. The optimized coatings showed no spallation/delamination and had a maximum of 6 mg/dm{sup 2} weight gain, which is 6 times smaller than that of a control sample of uncoated ZIRLO{sup ®} which showed a weight gain of 40.2 mg/dm{sup 2}. The optimized architecture features a ∼1 μm TiN top layer to prevent boehmite phase formation during corrosion and a TiN/TiAlN 8-layer architecture which provides the best corrosion performance. - Highlights: • The first study on multilayer TiAlN and TiN ceramic coatings on ZIRLO{sup ®} coupons. • Corrosion tests were performed at 360°C and 18.7 MPa for up to 90 days. • Coatings adhered well to the substrate, and showed no spallation/delamination. • Weight gains were six times lower than those of uncoated ZIRLO{sup ®} samples. • Longer and higher temperature corrosion tests will be discussed in a further paper.

  3. Numerical Simulation of Brazing TiC Cermet to Iron with TiZrNiCu Filler Metal

    Institute of Scientific and Technical Information of China (English)

    Lixia ZHANG; Jicai FENG

    2004-01-01

    The maximum thermal stress and stress concentration zones of iron/TiC cermet joint during cooling were studied in this paper. The results showed that the shear stress on iron/TiC cermet joint concentrates on the interface tip and the maximum shear stress appears on the left tip of iron/TiZrNiCu interlace. Positive tensile stress on TiC cermet undersurface concentrates on both sides of TiC cermet and its value decreases during cooling. Negative tensile stress on TiC cermet undersurface concentrates on the center of TiC cermet and its value increases during cooling. Brazing temperature has little effect on the development and maximum thermal stress.

  4. Synchrotron diffraction studies of TiC/FeTi cermets obtained by SHS

    International Nuclear Information System (INIS)

    Contreras, L.; Turrillas, X.; Mas-Guindal, M.J.; Vaughan, G.B.M.; Kvick, A.; Rodriguez, M.A.

    2005-01-01

    TiC/FeTi composites have been obtained in situ by Self-propagating High-temperature Synthesis (SHS) of an intimate mixture of compacted powders of elemental carbon, titanium and iron. The reaction has been followed in real time by X-ray diffraction at the ESRF. The mechanism of the reaction is discussed in terms of the formation of a liquid phase corresponding to the eutectic of the Fe/Ti system prior to the TiC synthesis. Temperatures of reaction have been estimated by correlating thermal expansion coefficients with diffraction peaks shifts. The microstructures obtained by this method, suitable for cutting tools and wear resistant applications, are presented

  5. Topotactic oxidation pathway of ScTiO3 and high-temperature structure evolution of ScTiO3.5 and Sc4Ti3O12-type phases.

    Science.gov (United States)

    Shafi, Shahid P; Hernden, Bradley C; Cranswick, Lachlan M D; Hansen, Thomas C; Bieringer, Mario

    2012-02-06

    The novel oxide defect fluorite phase ScTiO(3.5) is formed during the topotactic oxidation of ScTiO(3) bixbyite. We report the oxidation pathway of ScTiO(3) and structure evolution of ScTiO(3.5), Sc(4)Ti(3)O(12), and related scandium-deficient phases as well as high-temperature phase transitions between room temperature and 1300 °Cusing in-situ X-ray diffraction. We provide the first detailed powder neutron diffraction study for ScTiO(3). ScTiO(3) crystallizes in the cubic bixbyite structure in space group Ia3 (206) with a = 9.7099(4) Å. The topotactic oxidation product ScTiO(3.5) crystallizes in an oxide defect fluorite structure in space group Fm3m (225) with a = 4.89199(5) Å. Thermogravimetric and differential thermal analysis experiments combined with in-situ X-ray powder diffraction studies illustrate a complex sequence of a topotactic oxidation pathway, phase segregation, and ion ordering at high temperatures. The optimized bulk synthesis for phase pure ScTiO(3.5) is presented. In contrast to the vanadium-based defect fluorite phases AVO(3.5+x) (A = Sc, In) the novel titanium analogue ScTiO(3.5) is stable over a wide temperature range. Above 950 °C ScTiO(3.5) undergoes decomposition with the final products being Sc(4)Ti(3)O(12) and TiO(2). Simultaneous Rietveld refinements against powder X-ray and neutron diffraction data showed that Sc(4)Ti(3)O(12) also exists in the defect fluorite structure in space group Fm3m (225) with a = 4.90077(4) Å. Sc(4)Ti(3)O(12) undergoes partial reduction in CO/Ar atmosphere to form Sc(4)Ti(3)O(11.69(2)).

  6. Application of TiN/TiO2 coatings on stainless steel: composition and mechanical reliability

    Science.gov (United States)

    Nikolova, M. P.; Genov, A.; Valkov, S.; Yankov, E.; Dechev, D.; Ivanov, N.; Bezdushnyi, R.; Petrov, P.

    2018-03-01

    The paper reports on the effect of the substrate temperature (350 °C, 380 °C and 420 °C) during reactive magnetron sputtering of a TiN film on the phase composition, texture and mechanical properties of TiN/TiO2 coatings on 304L stainless steel substrates. Pure Ti was used as a cathode source of Ti. The texture and unit cell parameters of both TiN and TiO2 phases of the coating are discussed in relation with the tribological properties and adhesion of the coating. The scratch tests performed showed that the nitride deposited at 380 °C, having the highest unit cell parameter and a predominant (111) texture, possessed the lowest friction coefficient (μ), tangential force and brittleness. The anatase-type TiO2 with predominant (101) pole density and increased c unit cell parameter showed the highest stability on the nitride deposited at 420 °C. The results indicated that the friction coefficient, tangential force and critical forces of fracture could be varied by controlling the coating deposition temperature.

  7. Effect of Sr/Ti Ratio on the Photocatalytic Properties of SrTiO3

    International Nuclear Information System (INIS)

    Sulaeman, U; Yin, S; Sato, T

    2011-01-01

    Since strontium titanate is a wide gap semiconductor, it requires UV light to generate the photocatalytic activities. Modification of strontium titanate to show photocatalytic activity under visible light irradiation is the essential work to efficiently utilize the sun light energy for environmental application. It is expected that the synthesis of SrTiO 3 with variation of Sr/Ti atomic ratio could induce the defect crystals having unique photocatalytic properties. The SrTiO 3 with various Sr/Ti atomic ratios were synthesized by microwave-assisted solvothermal reaction of SrCl 2 .6H 2 O and Ti(OC 3 H 7 ) 4 in KOH aqueous solutions with different atomic ratios of Sr/Ti. The products were characterized by TG-DTA, XRD and DRS. The photocatalytic activity was determined by DeNO x ability using LED lamps with the wavelengths of 627 nm (red), 530 nm (green), 445 nm (blue) and 390 nm (UV). The nanoparticles of perovskite type SrTiO 3 with the particle size of 30-40 nm were successfully synthesized. The visible light responsive photocatalytic activity was generated by adding excess amount of Sr. The photocatalytic activity in visible light could be enhanced by an increase in the Sr/Ti atomic ratio up to 1.25, indicating that the visible light responsive photocatalytic activity is due to the generation of new band gap between the conduction band and valence band of SrTiO 3 by the formation of oxygen vacancy.

  8. Effect of TiC addition on oxidation behavior of TiC/316L composites and its mechanism%TiC添加对TiC/316L氧化行为的影响及其作用机制

    Institute of Scientific and Technical Information of China (English)

    蔺绍江; 熊惟皓; 石其年; 王赛玉

    2013-01-01

    采用粉末冶金法制备TiC颗粒含量不同的316L不锈钢复合材料,研究复合材料在800℃空气中的恒温氧化行为,分析TiC对复合材料氧化行为的影响和TiC的作用机制。结果表明:试样表面形成的氧化膜以TiO2、Cr2O3、Fe3O4和FeCr2O4为主要组成相。TiC的引入可以导致富Cr离子保护性氧化膜的形成,有利于复合材料抗氧化性能提高;但添加过多的TiC会导致TiC颗粒的聚集,TiC氧化反应的气体在颗粒聚集的区域集中产生和释放,降低了氧化膜的致密程度,恶化了试样的抗氧化性能。与其他试样相比,10%TiC/316L复合材料试样具有较好的抗氧化性能。%TiC/316L stainless steel composites with different particle contents were prepared by powder metallurgy. The isothermal oxidation behavior of TiC/316L composites sintered at 800℃in air was investigated. The effect of TiC on the oxidation behaviors of composites and the mechanism of TiC during the oxidation of composites were analyzed. The results show that the oxidation layer formed on the surface of samples mainly consists of TiO2, Cr2O3, Fe3O4 and FeCr2O4. TiC additions result in the formation of Cr-ion-riched oxide film which is beneficial to improving the oxidation resistance of the composites. However, the composites with too much TiC additions cause the agglomeration of TiC particles, which results the generation of a large quantity of gas formed by the TiC oxidation react in the particle gathered area, thereby reduces the densification of oxidation film, and causes the deterioration of the oxidation performance. Compared with other specimens, the composites with 10%TiC additions possesses excellent oxidation resistance.

  9. Tropical Journal of Pharmaceutical Research - Vol 15, No 3 (2016)

    African Journals Online (AJOL)

    Wan Wu, Wei Chen, Qiong Jin, 447-451 ... Chung-Shih Chen, Mei-Lin Wang, Rosa Huang Liu, Shih-Pin Chen, Tsong-Ming Lu, Wei-Yu Tsai, Chien-Fu Huang, ... Yan-Qiong Li, Rui Hu, Li-Hui Zhong, Qian Sun, You-Ping Yan, 527-533.

  10. Dynamic Optically Multiplexed Imaging

    Science.gov (United States)

    2015-07-29

    Dynamic Optically Multiplexed Imaging Yaron Rachlin, Vinay Shah, R. Hamilton Shepard, and Tina Shih Lincoln Laboratory, Massachusetts Institute of...V. Shah, and T. Shih “Design Architectures for Optically Multiplexed Imaging,” in submission 9 R. Gupta , P. Indyk, E. Price, and Y. Rachlin

  11. Compositionally graded Ti6Al4V + TiC made by direct laser fabrication using powder and wire

    International Nuclear Information System (INIS)

    Wang, F.; Mei, J.; Wu Xinhua

    2007-01-01

    Ti6Al4V reinforced with TiC has been fabricated as compositionally graded material by direct laser fabrication using TiC powder and Ti6Al4V wire which were fed simultaneously into the laser focal point. The microstructure along the length of the sample has been characterised using X-ray diffraction and scanning electron microscopy. The results show that the composition along the length changes as expected from the imposed changes in feed rate when allowance is made for the different capture efficiency for the powder and the wire. Some unmelted TiC has been observed in regions where the TiC fraction was high, but along most of the length of the samples TiC was completely melted and formed primary TiC, eutectic TiC and secondary TiC. Some preliminary tribological properties of the compositionally graded material were obtained using a sliding wear test which showed that the tribological properties of Ti6Al4V are improved by the reinforced TiC particles with the optimum frictional behaviour being found with approximately 24 vol% of TiC

  12. Thermal effect of TiC in the Mo/TiC/SiC system at elevated temperature

    International Nuclear Information System (INIS)

    Roger, Jerome; Audubert, Fabienne; Le Petitcorps, Yann

    2010-01-01

    In this study, we examined the effect induced by the addition of a TiC interlayer on the stability of the Mo/SiC system at high temperature. Indeed, Mo/SiC couple is unstable at high temperature with formation of Mo 2 C and Mo 5 Si 3 C x phases. In order to limit the degradation of Mo mechanical properties, a TiC film was inserted between Mo and SiC. Samples used in this work were prepared on metallic wires substrates, SiC and TiC being deposited by CVD. The protection given by TiC layer was considered in the 1473-1673 K temperature range and for TiC thicknesses up to about 60 μm. From our results, TiC is not effective enough to mitigate C and Si atoms diffusion. Nevertheless, a notable reduction of the reaction extent is obtained at any temperatures. The so-observed effect depends on the TiC thickness and the temperature. In actual fact, TiC efficiency increases when temperature and/or TiC layer thickness increases without reaching a complete protection.

  13. Observed magnetic dipole transitions in the ground terms of Ti XIV, Ti XV, and Ti XVII

    International Nuclear Information System (INIS)

    Suckewer, S.; Fonck, R.; Hinnov, E.

    1979-09-01

    Four observed spectrum lines in titanium-containing tokamak discharges have been identified as follows: TiXIV 2s 2 2p 5 2 P/sub 1/2/ → 2 P/sub 3/2/ at 2115.3 A, TiXV 2s 2 2p 4 3P 1 → 3 P 2 at 2544.8 A, TiXVII 2s 2 2p 2 3 P 2 → 3 P 1 at 3834.4 A and 3 P 1 → 3 P 0 at 3371.5 A. The identifications are based on observed time behavior and correlation with intensities of resonance lines of other titanium ions, and on general agreement with predicted wavelengths and intensities

  14. Structural and mechanical properties of titanium and titanium diboride monolayers and Ti/TiB2 multilayers

    International Nuclear Information System (INIS)

    Chu, K.; Lu, Y.H.; Shen, Y.G.

    2008-01-01

    Nano-multilayers represent a new class of engineering materials that are made up of alternating nanometer scale layers of two different components. In the present work a titanium (Ti) monolayer was combined with titanium diboride (TiB 2 ) to form a Ti/TiB 2 nano-multilayer. Designed experimental parameters enabled an evaluation of the effects of direct current bias voltage (U b ) and bilayer thickness (Λ) during multilayer deposition on the mechanical properties of reactively sputtered Ti/TiB 2 multilayer films. Their nanostructures and mechanical properties were characterized and analyzed using X-ray photoelectron spectroscopy (XPS), low-angle and high-angle X-ray diffraction (XRD), plan-view and cross-sectional high-resolution transmission electron microscopy (HRTEM), and microindentation measurements. Under the optimal bias voltage of U b = - 60 V, it was found that Λ (varied from 1.1 to 9.8 nm) was the most important factor which dominated the nanostructure and hardness. The hardness values obtained varied from 12 GPa for Ti and 15 GPa for TiB 2 monolayers, up to 33 GPa for the hardest Ti/TiB 2 multilayer at Λ = 1.9 nm. The observed hardness enhancement correlated to the layer thickness, followed a relation similar to the Hall-Petch strengthening dependence, with a generalized power of ∼ 0.6. In addition, the structural barriers between two materials (hcp Ti/amorphous TiB 2 ) and stress relaxation at interfaces within multilayer films resulted in a reduction of crack propagation and high-hardness

  15. Cytocompatibility and early osseointegration of nanoTiO{sub 2}-modified Ti-24 Nb-4 Zr-7.9 Sn surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Liu, X.H. [Department of Prosthodontics, China Medical University School of Stomatology, Shenyang (China); Wu, L., E-mail: wulin13@163.com [Department of Prosthodontics, China Medical University School of Stomatology, Shenyang (China); Ai, H.J. [Department of Prosthodontics, China Medical University School of Stomatology, Shenyang (China); Han, Y. [State Key laboratory for Mechanical Behaviour of Materials, Xi' an Jiaotong University, Xi' an (China); Hu, Y. [Department of Prosthodontics, China Medical University School of Stomatology, Shenyang (China)

    2015-03-01

    This study aimed to evaluate the cytocompatibility and early osseointegration of Ti-24 Nb-4 Zr-7.9 Sn (Ti-2448) surfaces that were modified with a nanoscale TiO{sub 2} coating. The coating was fabricated using a hydrothermal synthesis method to generate nanoTiO{sub 2}/Ti-2448. The surface characteristics of the samples were evaluated using scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and X-ray diffraction (XRD). The cytotoxicity of the fabricated nanoTiO{sub 2}/Ti-2448 was determined using MTT assays. The proliferation and alkaline phosphatase (ALP) activity of MC3T3-E1 osteoblasts cultured on nanoTiO{sub 2}/Ti-2448 were compared with those cultured on Ti-2448. Disk-shaped implants were placed in Wistar rats. The histological sections were stained with haematoxylin and eosin (HE), and the histocompatibility was analysed at 4 and 12 weeks post-implantation. Cylindrical implants were embedded in Japanese white rabbits, and the histological sections were stained with HE and anti-TGF-β1 to evaluate the histocompatibility and early osseointegration at 4, 12 and 26 weeks post-implantation. NanoTiO{sub 2}/Ti-2448 exhibited a rougher surface than did Ti-2448. NanoTiO{sub 2}/Ti-2448 was determined to be non-cytotoxic. More osteoblasts and higher ALP activity were observed for nanoTiO{sub 2}/Ti-2448 than Ti-2448 (p < 0.05). Few inflammatory cells were detected around nanoTiO{sub 2}/Ti-2448, and the expression of TGF-β1 on nanoTiO{sub 2}/Ti-2448 peaked at earlier time than that on Ti-2448. The results indicate that the cytocompatibility and early osseointegration were enhanced by the nanoTiO{sub 2} coating. - Highlights: • The cytocompatibility of nanoTiO2/Ti-2448 is first reported in our work. • The early osseointegration of nanoTiO2/Ti-2448 is first reported in our work. • We evaluate the biocompatibility of nanoTiO2/Ti-2448 by in-vitro and in-vivo tests.

  16. Structural and Mechanical Properties of TiN-TiC-TiO System: First Principle Study

    Science.gov (United States)

    Farhadizadeh, Ali Reza; Amadeh, Ahmad Ali; Ghomi, Hamidreza

    2017-11-01

    Mechanical and structural properties of ternary system of TiN-TiO-TiC are investigated using first principle methods. 70 different compositions of Ti 100 (NOC) 100 with cubic structure are examined in order to illustrate the trend of properties variations. The geometry of compounds is optimized, and then, their chemical stability is assessed. Afterward, shear, bulk and young moduli, Cauchy pressure, Zener ratio, hardness and {H}3/{E}2 ratio are computed based on elastic constants. Graphical ternary diagram is used to represent the trend of such properties when the content of nitrogen, oxygen and carbon varies. The results show that incorporation of oxygen into the system decreases the hardness and {H}3/{E}2 ratio while subsequently ductility increases due to positive Cauchy pressure. It is revealed that the maximum {H}3/{E}2 ratio occurs when both nitrogen and carbon with a little amount of oxygen are incorporated. Ti 100 N 30 C 70 owns the highest hardness and {H}3/{E}2 ratio equal to 39.5 and 0.2 GPa, respectively. In addition, the G/B of this compound, which is about 0.9, shows it is brittle. It is also observed that the solid solutions have better mechanical properties with respect to titanium nitride and titanium carbide. The obtained results could be used to enhance monolayer coatings as well as to design multilayers with specific mechanical properties. The authors would like to acknowledge the financial support of University of Tehran Science and Technology Park for this research under Grant No. 94061

  17. Highly piezoelectric BaTiO3 nanorod bundle arrays using epitaxially grown TiO2 nanomaterials.

    Science.gov (United States)

    Jang, Seon-Min; Yang, Su Chul

    2018-06-08

    Low-dimensional piezoelectric nanostructures such as nanoparticles, nanotubes, nanowires, nanoribbons and nanosheets have been developed for potential applications as energy harvesters, tunable sensors, functional transducers and low-power actuators. In this study, lead-free BaTiO 3 nanorod bundle arrays (NBA) with highly piezoelectric properties were successfully synthesized on fluorine-doped tin oxide (FTO) substrate via a two-step process consisting of TiO 2 epitaxial growth and BaTiO 3 conversion. Through the TiO 2 epitaxial growth on FTO substrate, (001) oriented TiO 2 nanostructures formed vertically-aligned NBA with a bundle diameter of 80 nm and an aspect ratio of six. In particular, chemical etching of the TiO 2 NBA was conducted to enlarge the surface area for effective Ba 2+ ion diffusion during the perovskite conversion process from TiO 2 to BaTiO 3 . The final structure of perovskite BaTiO 3 NBA was found to exhibit a feasible piezoelectric response of 3.56 nm with a clear phase change of 180° from the single BaTiO 3 bundle, by point piezoelectric forced microscopy (PFM) analysis. Consequently, highly piezoelectric NBA could be a promising nanostructure for various nanoscale electronic devices.

  18. Highly piezoelectric BaTiO3 nanorod bundle arrays using epitaxially grown TiO2 nanomaterials

    Science.gov (United States)

    Jang, Seon-Min; Yang, Su Chul

    2018-06-01

    Low-dimensional piezoelectric nanostructures such as nanoparticles, nanotubes, nanowires, nanoribbons and nanosheets have been developed for potential applications as energy harvesters, tunable sensors, functional transducers and low-power actuators. In this study, lead-free BaTiO 3 nanorod bundle arrays (NBA) with highly piezoelectric properties were successfully synthesized on fluorine-doped tin oxide (FTO) substrate via a two-step process consisting of TiO2 epitaxial growth and BaTiO3 conversion. Through the TiO2 epitaxial growth on FTO substrate, (001) oriented TiO2 nanostructures formed vertically-aligned NBA with a bundle diameter of 80 nm and an aspect ratio of six. In particular, chemical etching of the TiO2 NBA was conducted to enlarge the surface area for effective Ba2+ ion diffusion during the perovskite conversion process from TiO2 to BaTiO3. The final structure of perovskite BaTiO3 NBA was found to exhibit a feasible piezoelectric response of 3.56 nm with a clear phase change of 180° from the single BaTiO3 bundle, by point piezoelectric forced microscopy (PFM) analysis. Consequently, highly piezoelectric NBA could be a promising nanostructure for various nanoscale electronic devices.

  19. Amorphous Ti-Zr

    International Nuclear Information System (INIS)

    Rabinkin, A.; Liebermann, H.; Pounds, S.; Taylor, T.

    1991-01-01

    This paper is the first report on processing, properties and potential application of amorphous titanium/zirconium-base alloys produced in the form of a good quality continuous and ductile ribbon having up to 12.5 mm width. To date, the majority of titanium brazing is accomplished using cooper and aluminum-base brazing filler metals. The brazements produced with these filler metals have rather low (∼300 degrees C) service temperature, thus impeding progress in aircraft and other technologies and industries. The attempt to develop a generation of high temperature brazing filler metals was made in the late sixties-early seventies studies in detail were a large number of Ti-, Zr-Ti-Zr, Ti-V and Zr-V-Ti based alloys. The majority of these alloys has copper and nickel as melting temperature depressants. The presence of nickel and copper converts them into eutectic alloys having [Ti(Zr)] [Cu(Ni)], intermetallic phases as major structural constituents. This, in turn, results in high alloy brittleness and poor, if any, processability by means of conventional, i.e. melting-ingot casting-deformation technology. In spite of good wettability and high joint strength achieved in dozens of promising alloys, only Ti-15Cu-15Ni is now widely used as a brazing filler metal for high service temperature. Up until now this material could not be produced as a homogeneous foil and is instead applied as a clad strip consisting of three separate metallic layers

  20. Titanium carbide and its core-shelled derivative TiC-TiO2 as catalyst supports for proton exchange membrane fuel cells

    International Nuclear Information System (INIS)

    Ignaszak, Anna; Song, Chaojie; Zhu, Weimin; Zhang, Jiujun; Bauer, Alex; Baker, Ryan; Neburchilov, Vladimir; Ye, Siyu; Campbell, Stephen

    2012-01-01

    Both TiC and core-shelled TiC-TiO 2 are investigated as catalyst supports for proton exchange membrane fuel cells (PEMFCs). TiC is thermally stable, possesses both low solubility in sulphuric acid and high electronic conductivity. However, TiC undergoes irreversible electrochemical oxidation in dilute perchloric acid and the operating potential range of 0–1.2 V RHE . TiC-TiO 2 core–shell composite is found to be more stable than TiC. Both these materials are used as supports for Pt and Pt–Pd alloy catalysts (Pt/TiC, Pt 3 Pd/TiC and Pt 3 Pd/TiC-TiO 2 ) and are synthesized by microwave-assisted polyol process. The catalytic activities of both Pt 3 Pd/TiC and Pt 3 Pd/TiC-TiO 2 toward the oxygen reduction reaction (ORR) are much higher than those for Pt/TiC. Accelerated durability tests show that TiC supported catalysts are not electrochemically stable. The corresponding TiC-TiO 2 supported catalyst is more stable than that supported by TiC, indicating that with a protective oxide layer on the TiC core, TiC-TiO 2 is a promising PEMFC catalyst support.

  1. The constitution of the ternary system Ti-Ni-C; Die Konstitution des Dreistoffes Ti-Ni-C

    Energy Technology Data Exchange (ETDEWEB)

    Schuster, J.C.; Du, Y. [Technische Univ., Vienna (Austria). Inst. fuer Physikalische Chemie

    1998-12-31

    The system Ti-Ni-C was completely re-examined taking a new approach applying XRD, DTA, SEM-EDX and light microscopy, for elaboration of a complete thermodynamic description of the system. The carbon solubility in the binary Ti-Ni compounds is of significance only in the Ti{sub 2}Ni phase, and was found to be 4 at% at 900 C. The thermodynamic description thus achieved enables precise determination of the solubilities of Ti and C in solid or liquid nickel. (orig./CB) [Deutsch] Das System Ti-Ni-C wurde mittels XRD, DTA, SEM-EDX und Lichtmikroskopie umfassend neu untersucht mit dem Ziel, eine komplette thermodynamische Beschreibung zu ermoeglichen. Die Kohlenstoffloeslichkeit in den binaeren Ti-Ni Verbindungen ist nur fuer die Phase Ti{sub 2}Ni signifikant. Bei 900 C betrug sie 4 at% C. Die erarbeitete thermodynamische Beschreibung erlaubt eine praezise Darstellung der Ti- und C-Loeslichkeiten in festem und fluessigem Nickel. (orig.)

  2. Stress-induced martensitic transformations in NiTi and NiTi-TiC composites investigated by neutron diffraction

    International Nuclear Information System (INIS)

    Vaidyanathan, R.; Dunand, D.C.

    1999-01-01

    Superelastic NiTi (51.0 at.% Ni) specimens reinforced with 0, 10 and 20 vol.% TiC particles were deformed under uniaxial compression while neutron diffraction spectra were collected. The experiments yielded in-situ measurements of the thermoelastic stress-induced transformation. The evolution of austenite/martensite phase fractions and of elastic strains in the reinforcing TiC particles and the austenite matrix were obtained by Rietveld refinement during the loading cycle as the austenite transforms to martensite (and its subsequent back transformation during unloading). Phase fractions and strains are discussed in terms of load transfer in composites where the matrix undergoes a stress-induced phase transformation. (orig.)

  3. Electrochemical reduction induced self-doping of Ti3+ for efficient water splitting performance on TiO2 based photoelectrodes

    KAUST Repository

    Zhang, Zhonghai

    2013-01-01

    Hetero-element doping (e.g., N, F, C) of TiO2 is inevitably accompanied by significantly increased structural defects due to the dopants\\' nature being foreign impurities. Very recently, in situ self-doping with homo-species (e.g., Ti3+) has been emerging as a rational solution to enhance TiO2 photoactivity within both UV and visible light regions. Herein we demonstrate that conventional electrochemical reduction is indeed a facile and effective strategy to induce in situ self-doping of Ti3+ into TiO2 and the self-doped TiO2 photoelectrodes showed remarkably improved and very stable water splitting performance. In this study, hierarchical TiO2 nanotube arrays (TiO2 NTs) were chosen as TiO2 substrates and then electrochemically reduced under varying conditions to produce Ti3+ self-doped TiO2 NTs (ECR-TiO2 NTs). The optimized saturation photocurrent density and photoconversion efficiency on the ECR-TiO2 NTs under simulated AM 1.5G illumination were identified to be 2.8 mA cm-2 at 1.23 V vs. RHE and 1.27% respectively, which are the highest values ever reported for TiO 2 based photoelectrodes. The electrochemical impedance spectra measurement confirms that the electrochemical induced Ti3+ self-doping improved the electrical conductivity of the ECR-TiO2 NTs. The versatility and effectiveness of the electrochemical reduction method for Ti3+ self-doping in P25 based TiO2 was also examined and confirmed. This journal is © 2013 the Owner Societies.

  4. Study on improved tribological properties by alloying copper to CP-Ti and Ti-6Al-4V alloy.

    Science.gov (United States)

    Wang, Song; Ma, Zheng; Liao, Zhenhua; Song, Jian; Yang, Ke; Liu, Weiqiang

    2015-12-01

    Copper alloying to titanium and its alloys is believed to show an antibacterial performance. However, the tribological properties of Cu alloyed titanium alloys were seldom studied. Ti-5Cu and Ti-6Al-4V-5Cu alloys were fabricated in the present study in order to further study the friction and wear properties of titanium alloys with Cu additive. The microstructure, composition and hardness were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM) and hardness tester. The tribological behaviors were tested with ZrO2 counterface in 25% bovine serum using a ball-on-disc tribo-tester. The results revealed that precipitations of Ti2Cu intermetallic compounds appeared in both Ti-5Cu and Ti-6Al-4V-5Cu alloys. The tribological results showed an improvement in friction and wear resistance for both Ti-5Cu and Ti-6Al-4V-5Cu alloys due to the precipitation of Ti2Cu. The results also indicated that both CP-Ti and Ti-5Cu behaved better wear resistance than Ti-6Al-4V and Ti-6Al-4V-5Cu due to different wear mechanisms when articulated with hard zirconia. Both CP-Ti and Ti-5Cu revealed dominant adhesive wear with secondary abrasive wear mechanism while both Ti-6Al-4V and Ti-6Al-4V-5Cu showed severe abrasive wear and cracks with secondary adhesive wear mechanism due to different surface hardness integrated by their microstructures and material types. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Effect of annealing process on TiN/TiC bilayers grown by pulsed arc discharge

    International Nuclear Information System (INIS)

    Ramos-Rivera, L.; Escobar, D.; Benavides-Palacios, V.; Arango, P.J.; Restrepo-Parra, E.

    2012-01-01

    In this work, a study of annealing process effect on TiN/TiC bilayer is presented. The annealing temperature was varied between room temperature and 500 °C. Materials were produced by the plasma-assisted pulsed vacuum arc discharge technique. In order to grow the films, a target of Ti with 99.9999% purity and stainless-steel 304 substrate were used. For the production of TiN layer, the reaction chamber was filled up with nitrogen gas until reaching 25 Pa and the discharge was performed at 310 V. The TiC layer was grown in a methane atmosphere at 30 Pa and 270 V. X-ray diffraction and X photoelectron spectroscopy were employed for studying the structure and chemical composition evolution during the annealing process. At 400 °C, TiO 2 phase begun to appear and it was well observed at 500 °C. Crystallite size and microstrain was obtained as a function of the annealing temperature. XPS technique was employed for analyzing the bilayers before and after the annealing process. Narrow spectra of Ti2p, N1s and O1s were obtained, presenting TiO phases.

  6. Titanium Matrix Composite Ti/TiN Produced by Diode Laser Gas Nitriding

    Directory of Open Access Journals (Sweden)

    Aleksander Lisiecki

    2015-01-01

    Full Text Available A high power direct diode laser, emitting in the range of near infrared radiation at wavelength 808–940 nm, was applied to produce a titanium matrix composite on a surface layer of titanium alloy Ti6Al4V by laser surface gas nitriding. The nitrided surface layers were produced as single stringer beads at different heat inputs, different scanning speeds, and different powers of laser beam. The influence of laser nitriding parameters on the quality, shape, and morphology of the surface layers was investigated. It was found that the nitrided surface layers consist of titanium nitride precipitations mainly in the form of dendrites embedded in the titanium alloy matrix. The titanium nitrides are produced as a result of the reaction between molten Ti and gaseous nitrogen. Solidification and subsequent growth of the TiN dendrites takes place to a large extent at the interface of the molten Ti and the nitrogen gas atmosphere. The direction of TiN dendrites growth is perpendicular to the surface of molten Ti. The roughness of the surface layers depends strongly on the heat input of laser nitriding and can be precisely controlled. In spite of high microhardness up to 2400 HV0.2, the surface layers are crack free.

  7. Advances in SCA and RF-DNA Fingerprinting Through Enhanced Linear Regression Attacks and Application of Random Forest Classifiers

    Science.gov (United States)

    2014-09-18

    22:477– 505 , 2007. [21] Bushnell, Michael L. and Vishwani Agrawal. Essentials of Electronic Testing for Digital, Memory, and Mixed-Signal VLSI...Investigation”. Knowledge and information systems, 10(4):453–472, 2006. [68] Liang, Nia -Chiang, Ping-Chieh Chen, Tony Sun, Guang Yang, Ling-Jyh Chen

  8. Photocatalytic degradation of water surface oils by CoPcS-TiO2-beads and TiO2-beads%CoPcS/TiO2/beads及TiO2/beads光催化降解水面浮油

    Institute of Scientific and Technical Information of China (English)

    张晓叶; 闰永胜; 孔峰; 赵瑞平; 陈林; 钱华伟

    2008-01-01

    以钛酸四丁酯为原料,空心玻璃微珠(beads)为载体,采用溶胶一凝胶法制备出TiO2/beads光催化剂,用浸渍法制备出CoPcS/TiO2/beads新型光催化剂.研究了利用TiO2/beads及CoPcS/TiO2/beads光催化剂降解水面漂浮植物油的最优条件.结果表明:(1)溶胶-凝胶法制备TiO2/beads的最佳条件为:空心玻璃微珠浸渍3次,450~550℃下焙烧2 h.用CoPcS对TiO2/beads进行改性时,TiO2/beads的最1圭浸渍时间为30 min.(2)在中性或酸性条件下,375 W中压汞灯光照2~3 h,TiO2/eads与CoPcS/TiO2/beads的最佳用量分别为3 g和1 g(植物油3 g),在此条件下,植物油的去除率都高达90%.(3)微量H2O2对TiO2/beads和CoPcS/TiO2/beads的光催化活性都有很大的提高.对于TiO2/beads催化剂,H2O2的最佳用量为5~11 mmol/L;对于CoPcS/TiO2/beads催化剂,H2O2的最佳用量为5~30 mmol/L.(4)新型光催化剂CoPcS/TiO2/aeads比TiO2/beads具有更好的除油性能.

  9. Effect of nano-TiC addition on sinterability and mechanical properties of TiC high temperature ceramics%纳米TiC加入量对TiC高温陶瓷烧结和力学性能的影响

    Institute of Scientific and Technical Information of China (English)

    徐广平; 宋一华; 何江荣; 程利霞; 谢志鹏

    2013-01-01

    为研究纳米TiC在烧结过程中对TiC基体烧结和力学性能的影响,在粒径约3μm的TiC微粉中分别添加质量分数为0、10%、20%、50%、90%的纳米TiC,采用放电等离子体烧结工艺(于1 600℃烧结5 min,烧结压力50 MPa)制备出了TiC高温陶瓷.利用阿基米德排水法、SEM、压痕法等测试手段表征烧结后陶瓷的烧结性、显微结构及力学性能,并从致密度和显微结构的变化讨论了纳米TiC加入量对TiC陶瓷烧结的影响,从硬度和断裂韧性的变化探讨了纳米TiC量对其力学性能的影响.结果表明:纳米TiC在基体中的分散性是影响TiC陶瓷烧结性和力学性能的主要原因,加入少量(10%质量分数)纳米TiC时,分散性较好,有助于提高TiC陶瓷的烧结性和力学性能;添加纳米TiC可以明显细化TiC陶瓷的显微结构组织;当纳米TiC质量分数为10%时,TiC陶瓷的断裂韧性最大,呈现明显的裂纹偏转、桥接等增韧机制.

  10. Micromechanisms of fracture and fatigue in Ti3Al based and TiAl based intermetallics

    International Nuclear Information System (INIS)

    James, A.W.; Chave, R.A.; Hippsley, C.A.; Bowen, P.

    1993-01-01

    Micromechanisms of fracture and fatigue crack growth resistance in specific Ti 3 Al based and TiAl based intermetallics are reviewed. Effects of test temperature, environment and microstructure on crack growth resistance are considered in detail for several Ti 3 Al and Ti'Al based intermetallic systems under development. The implications of these studies for the structural reliability of these materials is also addressed briefly. (orig.)

  11. Characterization studies of β-Ti3O5 and λ-Ti3O5 nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Tasca, Kelin Regina; Giles, Carlos, E-mail: kelinregina@gmail.com [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Instituto de Fisica Gleb Wataghin

    2016-07-01

    Full text: Recently, a new phase of Ti3O5 with properties of a metallic conductor and thermodynamically stable at room temperature due to nanoscale effects was reported. The new phase, namely λ-Ti3O5, presents a monoclinic structure with characteristics of a near-metallic conductor. At room temperature a photoreversible phase transition between λ-Ti3O5 and the conventional semiconductor phase, β-Ti3O5, is induced by light excitation. The thermodynamic analysis suggests that the photoinduced metal-semiconductor phase transition is a result of a transition from λ-Ti3O5, a metastable phase thermodynamically trapped at a local energy-minimum state, to a truly stable phase β-Ti3O5, by irradiation of a pulsed laser light. The direction of the photoinduced phase transition can be controlled by adjusting the excitation fluence at a constant wavelength, or changing the wavelength. In both cases, the fluence and the wavelength have well defined threshold values.Due to the existence of a photoinduced phase transition and to environmentally benign characteristics this material is a strong candidate for high density optical storage media. In the present work Ti3O5 nanoparticles were synthesized by sintering 30 nm commercial anatase-TiO{sub 2} nanoparticles in hydrogen flux at 1200 deg C during 2 h. The sample was characterized by x-ray powder diffractometry (XRD) and the results showed a mixed phase of λ-Ti3O5 and β-Ti3O5. With the purpose to perform future time-resolved XRD experiments, a thin film of the mixed Ti3O5 sample was prepared in a FTO glass substrate and heated up to 450 deg C. From this process a thin film of λ-Ti3O5 nanoparticles with a small amount of rutile-TiO2 resulted. These results are different from the so far published work and can contribute to the comprehension of this phenomena. To better understand this phase transition XRD as a function of temperature and under the influence of laser incidence will be presented. (author)

  12. Characterization studies of β-Ti3O5 and λ-Ti3O5 nanoparticles

    International Nuclear Information System (INIS)

    Tasca, Kelin Regina; Giles, Carlos

    2016-01-01

    Full text: Recently, a new phase of Ti3O5 with properties of a metallic conductor and thermodynamically stable at room temperature due to nanoscale effects was reported. The new phase, namely λ-Ti3O5, presents a monoclinic structure with characteristics of a near-metallic conductor. At room temperature a photoreversible phase transition between λ-Ti3O5 and the conventional semiconductor phase, β-Ti3O5, is induced by light excitation. The thermodynamic analysis suggests that the photoinduced metal-semiconductor phase transition is a result of a transition from λ-Ti3O5, a metastable phase thermodynamically trapped at a local energy-minimum state, to a truly stable phase β-Ti3O5, by irradiation of a pulsed laser light. The direction of the photoinduced phase transition can be controlled by adjusting the excitation fluence at a constant wavelength, or changing the wavelength. In both cases, the fluence and the wavelength have well defined threshold values.Due to the existence of a photoinduced phase transition and to environmentally benign characteristics this material is a strong candidate for high density optical storage media. In the present work Ti3O5 nanoparticles were synthesized by sintering 30 nm commercial anatase-TiO 2 nanoparticles in hydrogen flux at 1200 deg C during 2 h. The sample was characterized by x-ray powder diffractometry (XRD) and the results showed a mixed phase of λ-Ti3O5 and β-Ti3O5. With the purpose to perform future time-resolved XRD experiments, a thin film of the mixed Ti3O5 sample was prepared in a FTO glass substrate and heated up to 450 deg C. From this process a thin film of λ-Ti3O5 nanoparticles with a small amount of rutile-TiO2 resulted. These results are different from the so far published work and can contribute to the comprehension of this phenomena. To better understand this phase transition XRD as a function of temperature and under the influence of laser incidence will be presented. (author)

  13. Diffusion characteristics in the Cu-Ti system

    Energy Technology Data Exchange (ETDEWEB)

    Laik, Arijit; Kale, Gajanan Balaji [Bhabha Atomic Reseach Centre, Mumbai (India). Materials Science Div.; Bhanumurthy, Karanam [Bhabha Atomic Reseach Centre, Mumbai (India). Scientific Information Resource Div.; Kashyap, Bhagwati Prasad [Indian Institute of Technology Bombay, Mumbai (India). Dept. of Metallurgical Engineering

    2012-06-15

    The formation and growth of intermetallic compounds by diffusion reaction of Cu and Ti were investigated in the temperature range 720 - 860 C using bulk diffusion couples. Only four, out of the seven stable intermediate compounds of the Cu-Ti system, were formed in the diffusion reaction zone in the sequence CuTi, Cu{sub 4}Ti, Cu{sub 4}Ti{sub 3} and CuTi{sub 2}. The activation energies required for the growth of these compounds were determined. The diffusion characteristics of Cu{sub 4}Ti, CuTi and Cu{sub 4}Ti{sub 3} and Cu(Ti) solid solution were evaluated. The activation energies for diffusion in these compounds were 192.2, 187.7 and 209.2 kJ mol{sup -1} respectively, while in Cu(Ti), the activation energy increased linearly from 201.0 kJ mol{sup -1} to 247.5 kJ mol{sup -1} with increasing concentration of Ti, in the range 0.5 - 4.0 at.%. The impurity diffusion coefficient of Ti in Cu and its temperature dependence were also estimated. A correlation between the impurity diffusion parameters for several elements in Cu matrix has been established. (orig.)

  14. Thermodynamics of TiB2 from Ti-B-N studies

    International Nuclear Information System (INIS)

    Yurick, T.J.; Spear, K.E.

    1979-01-01

    Thermodynamic data for the formation of TiB 2 have been extracted from equilibrium pressure-temperature-composition investigations in the ternary Ti-B-N system. The value ΔH 0 sub(f,298)(TiB 2 ) = -72.7 +- 1.6 kcal/mole determined from a 3rd law analysis of the present results does not agree either with standard reference book values of about -67 kcal/mole or with later calorimetric results of about -77 kcal/mole. The uncertainty listed with the value reported in this paper is a result of a detailed error analysis on possible random and systematic errors encountered in our investigation. (orig.) [de

  15. Cu-Ti Formation in Nb-Ti/Cu Superconducting Strand Monitored by in situ Techniques

    CERN Document Server

    Pong, I; Pong, Ian; Gerardin, Alexandre; Scheuerlein, Christian; Bottura, Luca

    2010-01-01

    In order to investigate the high temperature exposure effect on Nb-Ti/Cu superconducting strands, as might be encountered in joining by soldering and in cabling annealing, X-ray diffraction and resistometry measurements were performed in situ during heat treatment, and complemented by conventional metallography, mechanical tests and superconducting properties measurements. Changes of the Nb-Ti nanostructure at temperatures above 300 degrees C are manifested in the degradation of critical current in an applied external magnetic field, although degradation at self field was insignificant up to 400 degrees C for several minutes. Above 500 degrees C, the formation of various Cu-Ti intermetallic compounds, due to Ti diffusion from Nb-Ti into Cu, is detected by in situ XRD albeit not resolvable by SEM-EDS. There is a ductile to brittle transition near 600 degrees C, and liquid formation is observed below 900 degrees C. The formation of Cu-Ti causes a delayed reduction of the residual resistivity ratio (RRR) and adv...

  16. Wetting induced by near-surface Ti-enrichment in the CaF2/In-Ti and CaF2/Cu-Ti systems

    International Nuclear Information System (INIS)

    Froumin, N.; Barzilai, S.; Aizenshtein, M.; Lomberg, M.; Frage, N.

    2008-01-01

    This paper is concerned with the wetting of CaF 2 by liquid Cu and In and with the effect of Ti additions to the melt. According to thermodynamic analysis and to the experimental observations, the significantly decreased contact angle following the addition of Ti to the molten metals is not due to the formation of interfacial fluoride phases, in contrast to previously reported results. Ab initio density functional calculations indicate that preferential Ti adsorption takes place at the near CaF 2 surface. It is suggested that the presence of a Ti-enriched liquid, adjacent to the substrate, gives rise, by means of heterogeneous nucleation, to the formation of a thin intermetallic compound layer that stands behind the experimentally observed enhanced wetting. The suggested wetting mechanism is supported by the notable correlation that has been observed between the temperature dependence of the contact angle and the temperature domains, associated with the presence of intermetallic compounds in both Me-Ti (Me = Cu, In) binary systems

  17. Active Ti Species in TiCl3-Doped NaAlH4. Mechanism for Catalyst Deactivation

    NARCIS (Netherlands)

    Balde, C.P.; Stil, H.A.; van der Eerden, A.M.J.; de Jong, K.P.; Bitter, J.H.

    2007-01-01

    The nature of the active Ti species in TiCl3-doped NaAlH4, a promising hydrogen storage material, was studied as a function of the desorption temperature with Ti K-edge extended X-ray absorption fine structure (EXAFS) spectroscopy, Ti K-edge X-ray absorption near-edge structure (XANES) spectroscopy,

  18. Microstructures and Properties of Laser Clad TiC Reinforced Ti Matrix Composite Coatings%激光熔覆TiC增强Ti基复合涂层的组织与性能

    Institute of Scientific and Technical Information of China (English)

    孙耀宁

    2008-01-01

    利用激光熔覆技术在工业纯钛表面分别预置TiC、(Ti+C)、(Ti+TiC)粉末制备了TiC增强Ti基复合涂层,对复合涂层的组织与性能进行了分析和测试.结果表明:制备的涂层均由TiC增强相和α'-Ti组成;激光熔覆纯TiC涂层出现了陶瓷的分层现象,对组织和性能不利;激光熔覆(Ti+C)原位反应生成了TiC,但组织较粗大;熔覆(Ti+TiC)组织均匀致密.三种熔覆层硬度大小关系为:加(Ti+TiC)>加TiC>加(Ti+C),最高硬度分别为Hv1246、Hv1213、Hv1135,加(Ti+TiC)涂层硬度最高.导致该熔覆层硬度最高的主要原因是添加的Ti对熔覆有利,且生成了数量较多、较致密均匀的硬质TiC陶瓷相.

  19. Effects of Ti and TiC ceramic powder on laser-cladded Ti-6Al-4V in situ intermetallic composite

    Energy Technology Data Exchange (ETDEWEB)

    Ochonogor, O.F. [Department of Chemical and Metallurgical Engineering, Faculty of Engineering and the Built Environment, Tshwane University of Technology, Pretoria, X680 0001 (South Africa); Meacock, C. [Council for Scientific and Industrial Research, National Laser Centre, Pretoria (South Africa); Abdulwahab, M. [Department of Chemical and Metallurgical Engineering, Faculty of Engineering and the Built Environment, Tshwane University of Technology, Pretoria, X680 0001 (South Africa); Pityana, S. [Department of Chemical and Metallurgical Engineering, Faculty of Engineering and the Built Environment, Tshwane University of Technology, Pretoria, X680 0001 (South Africa); Council for Scientific and Industrial Research, National Laser Centre, Pretoria (South Africa); Popoola, A.P.I., E-mail: popoolaapi@tut.ac.za [Department of Chemical and Metallurgical Engineering, Faculty of Engineering and the Built Environment, Tshwane University of Technology, Pretoria, X680 0001 (South Africa)

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer The wear resistance of the laser clad surfaces was enhanced significantly with fifteen-folds wear rate reduction. Black-Right-Pointing-Pointer Micro-hardness of the clad zones indicated a significant improvement of over two-folds greater than the substrate. Black-Right-Pointing-Pointer Microstructures showed fine crystal grains distribution of ceramic particles that formed interstitial carbides in the titanium matrix composites. - Abstract: Titanium metal matrix composite (MMCs) was developed on titanium alloy (Ti-6Al-4V) substrate with the aim of improving the hardness and wear properties by laser cladding technique using a Rofin Sinar 4 kW Nd: YAG laser. Wear investigations were carried out with the aid of three body abrasion tester. The resultant microstructure show homogeneous distribution of TiC particles free from cracks and pores. Multiple track deposited systems with 50% overlap revealed micro-hardness increase from 357.3 HV{sub 0.1}for the substrate reaching a peak as high as 922.2 HV{sub 0.1} for 60%Ti + 40%TiC and the least 665.3 HV{sub 0.1} for 80%Ti + 20%TiC MMCs. The wear resistance of the materials improved significantly, indicating a fifteen-fold wear rate reduction due to the proper distribution of ceramic particles thereby forming interstitial carbides as revealed by the X-ray diffraction spectrum.

  20. Microstructure and mechanical properties of TiB2–TiC–WC composite ceramic tool materials

    International Nuclear Information System (INIS)

    Song, Jinpeng; Huang, Chuanzhen; Zou, Bin; Liu, Hanlian; Wang, Jun

    2012-01-01

    Highlights: ►Effect of sintering parameters on TiB 2 –TiC–WC composites has been investigated. ► Ni element was dispersed in the interface between WC and matrix grains. ► The fracture mode changed from intergranular fracture to transgranular fracture. ► The microstructure and mechanical properties of the composite were improved. -- Abstract: TiB 2 –TiC–WC composites with Ni as a sintering aid were fabricated by a hot-press technique at 1700 °C and 1650 °C for 1 h, respectively. The microstructure and mechanical properties were investigated. The composites were analyzed by means of scanning electron microscope (SEM), X-ray diffraction (XRD) and energy dispersive spectrometry (EDS). The matrix phases consisted of TiB 2 and TiC. No severe chemical reactions happened between the additive and matrix. The microstructure consisted of the fine WC grains and uniform matrix grains. When the proper WC content added to TiB 2 –TiC composites, the growth of matrix grains was inhibited and the mechanical properties of the composites were improved. The interface energy was strengthened by Ni that dispersed in the interfaces among WC grains and matrix grains, which made the fracture mode change from intergranular fracture to transgranular fracture. The transgranular fracture and the pulling out of WC grains played a predominant role in the propagating of cracks when WC content was 20 wt.% in TiB 2 –TiC–WC composites. The optimal mechanical properties of TiB 2 –TiC–20 wt.%WC composite were 955.71 MPa of flexural strength, 7.5 MPa m 1/2 of fracture toughness and 23.5 GPa of Vickers hardness.

  1. Crystal structures of lazulite-type oxidephosphates TiIIITiIV3O3(PO4)3 and MIII4TiIV27O24(PO4)24 (MIII=Ti, Cr, Fe)

    International Nuclear Information System (INIS)

    Schoeneborn, M.; Glaum, R.; Reinauer, F.

    2008-01-01

    Single crystals of the oxidephosphates Ti III Ti IV 3 O 3 (PO 4 ) 3 (black), Cr III 4 Ti IV 27 O 24 (PO 4 ) 24 (red-brown, transparent), and Fe III 4 Ti IV 27 O 24 (PO 4 ) 24 (brown) with edge-lengths up to 0.3 mm were grown by chemical vapour transport. The crystal structures of these orthorhombic members (space group F2dd ) of the lazulite/lipscombite structure family were refined from single-crystal data [Ti III Ti IV 3 O 3 (PO 4 ) 3 : Z=24, a=7.3261(9) A, b=22.166(5) A, c=39.239(8) A, R 1 =0.029, wR 2 =0.084, 6055 independent reflections, 301 variables; Cr III 4 Ti IV 27 O 24 (PO 4 ) 24 : Z=1, a=7.419(3) A, b=21.640(5) A, c=13.057(4) A, R 1 =0.037, wR 2 =0.097, 1524 independent reflections, 111 variables; Fe III 4 Ti IV 27 O 24 (PO 4 ) 24 : Z=1, a=7.4001(9) A, b=21.7503(2) A, c=12.775(3) A, R 1 =0.049, wR 2 =0.140, 1240 independent reflections, 112 variables). For Ti III Ti IV O 3 (PO 4 ) 3 a well-ordered structure built from dimers [Ti III,IV 2 O 9 ] and [Ti IV,IV 2 O 9 ] and phosphate tetrahedra is found. The metal sites in the crystal structures of Cr 4 Ti 27 O 24 (PO 4 ) 24 and Fe 4 Ti 27 O 24 (PO 4 ) 24 , consisting of dimers [M III Ti IV O 9 ] and [Ti IV,IV 2 O 9 ], monomeric [Ti IV O 6 ] octahedra, and phosphate tetrahedra, are heavily disordered. Site disorder, leading to partial occupancy of all octahedral voids of the parent lipscombite/lazulite structure, as well as splitting of the metal positions is observed. According to Guinier photographs Ti III 4 Ti IV 27 O 24 (PO 4 ) 24 (a=7.418(2) A, b=21.933(6) A, c=12.948(7) A) is isotypic to the oxidephosphates M III 4 Ti IV 27 O 24 (PO 4 ) 24 (M III : Cr, Fe). The UV/vis spectrum of Cr 4 Ti 27 O 24 (PO 4 ) 24 reveals a rather small ligand-field splitting Δ o =14,370 cm -1 and a very low nephelauxetic ratio β=0.72 for the chromophores [Cr III O 6 ] within the dimers [Cr III Ti IV O 9 ]. - Graphical abstract: Single crystals of the oxidephosphates Ti III Ti IV 3 O 3 (PO 4 ) 3 (black), Cr III 4 Ti IV 27 O

  2. Influence of Fe underlayers on stress evolution of Ti in Ti/Fe multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Wan, Li; Thompson, Gregory, E-mail: gthompson@eng.ua.edu [Department of Metallurgical Engineering, The University of Alabama, Tuscaloosa, Alabama 35487-0202 (United States)

    2016-11-15

    A series of 40–2 nm bilayer spacing Ti/Fe multilayers were sputter-deposited. As the length scale of individual Ti layers equaled to 2 nm, Ti phase transforms from a hexagonal close packed (hcp)-to-body centered cubic (bcc) crystal structures for equal layer thicknesses in Ti/Fe multilayers. Further equal reductions in bilayer spacing to less than 1 nm resulted in an additional transformation from a crystalline to amorphous structure. Atom probe tomography reveals significant intermixing between layers which contributes to the observed phase transformations. Real-time, intrinsic growth stress measurements were also performed to relate the adatom mobility to these phase transformations. For the hcp Ti/bcc Fe multilayers of equivalent volume fractions, the multilayers undergo an overall tensile stress state to a compressive stress state with decreasing bilayer thickness for the multilayers. When the above phase transformations occurred, a modest reduction in the overall compressive stress of the multilayer was noted. Depending on the Fe thickness, the Ti growth was observed to be a tensile to compressive growth change to a purely compressive growth for thinner bilayer spacing. Fe retained a tensile growth stress regardless of the bilayer spacing studied.

  3. TiC含量对AlN-TiC复相材料导热性能的影响%Effect of TiC Content on the Thermal Conductivity of AlN-TiC Composites

    Institute of Scientific and Technical Information of China (English)

    程卫华

    2011-01-01

    采用热压烧结工艺制备了AlN-TiC复相材料.通过激光导热仪,研究了TiC含量对材料导热性能的影响.结果表明:随着TiC的质量分数的增加,复相材料的热导率逐渐下降,当TiC的质量分数增至50t%时,热导率由102.9 W/(m·K)下降到46.6 W/(m·K),并对AlN-TiC的相组成和显微结构进行了观察分析.

  4. Residual stress in coated low-Z films of TiC and TiN. Pt. 2

    International Nuclear Information System (INIS)

    Yoshizawa, I.; Kabeya, Z.; Kamada, K.

    1984-01-01

    The correlations of the residual stresses with microstructures of TiC and TiN films deposited onto various substrates were examined by means of observations of SEM micrographs, X-ray back-reflected Debye rangs and diffraction line profile of X-ray spectrometer chart. It was found that specimens with lower residual stress generally show sharp line profile and good separation between Ksub(α1) and Ksub(α2) diffraction peaks in both TiN and TiC films, indicating better crystalline perfection. PVD coated TiC films on Mo and Inconel substrates show poor separation of Ksub(α1) and Ksub(α2) peaks, namely due to higher residual stresses in comparison with those of CVD coated TiN and TiC films on Mo or Inconel substrate. In CVD TiC/Pocographite system, with film thickness ranging from 10 to 100 μm, the grain size increase with increasing the thickness, except 100 μm thick specimen which has the smallest grain size in this group. However, the sharpness of diffraction profile is best in 20 μm thick film, and worst in 100 μm thick film. This is in good correlation with the amount of residual stress. (orig.)

  5. Impulse Pressuring Diffusion Bonding of TiC Cermet to Stainless Steel Using Ti/Nb Interlayer

    Directory of Open Access Journals (Sweden)

    LI Jia

    2017-03-01

    Full Text Available Impulse pressuring diffusion bonding(IPDB and constant pressuring diffusion bonding(CPDB of TiC cermet to 304 stainless steel(304SS using Ti/Nb interlayer was carried out at 890℃ under a impulse pressuring of 2-10MPa and a constant pressuring of 10MPa within a duration of only 4-12min, and a robust metallurgical bonding was achieved. Microstructure characterization and shear performance of the IPDB and CPDB joints were analyzed by SEM, EDS, XRD and shearing test. The results show that the interface phases in those two kinds of joints are similar, which are mainly σ phase,(β-Ti, Nb and α+β-Ti solid solution. When the joint is bonded for 10min, shear strength of TiC/304SS CPDB joints is 55.6MPa, while the shear strength of IPDB joints reaches 110MPa. The fracture of CPDB joints is TiC cermet fracture, while that of IPDB joints is mixed fracture by alternated between TiC cermet and reaction layer.

  6. The role of TiB2 in strengthening TiB2 reinforced aluminium casting composites

    International Nuclear Information System (INIS)

    Chen, Z; Kang, H; Zhao, Y; Zheng, Y; Wang, T

    2016-01-01

    With an aim of developing high quality in situ TiB 2 reinforced aluminium foundry alloy based composites, the conventional direct synthesis method was modified into a two-step route. In step one we optimized the halide salt route to fabricate in situ TiB 2 particulate reinforced aluminium matrix composites and in step two we investigated the effects of the Al-5wt.% TiB 2 composite, as a “master composite”, on strengthening the practical foundry alloys. The in situ formed TiB 2 particles play two roles while strengthening the composites: (1) The grain refinement effect that improves the quality of the alloy matrix; and (2) The interactions between the hard particulates and the matrix add extra increment to the material strength. In different alloy systems, TiB 2 may play distinct roles in these two aspects (figure 1). Further analysis of the strengthening mechanisms shows that particle agglomeration behaviour during solidification is responsible for the latter one. The present work details the role of TiB 2 in strengthening TiB 2 reinforced aluminium casting composites. (paper)

  7. Electrochemical and surface behavior of hydyroxyapatite/Ti film on nanotubular Ti-35Nb-xZr alloys

    International Nuclear Information System (INIS)

    Jeong, Yong-Hoon; Choe, Han-Cheol; Brantley, William A.

    2012-01-01

    In this paper, we investigated the electrochemical and surface behavior of hydroxyapatite (HA)/Ti films on the nanotubular Ti-35Nb-xZr alloy. The Ti-35Nb-xZr ternary alloys with 3-10 wt.% Zr content were made by an arc melting method. The nanotubular oxide layers were developed on the Ti-35Nb-xZr alloys by an anodic oxidation method in 1 M H 3 PO 4 electrolyte containing 0.8 wt% NaF at room temperature. The HA/Ti composite films on the nanotubular oxide surfaces were deposited by a magnetron sputtering method. Their surface characteristics were analyzed by field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS) and an X-ray diffractometer (XRD). The corrosion behavior of the specimens was examined through potentiodynamic and AC impedance tests in 0.9% NaCl solution. From the results, the Ti-35Nb-xZr alloys showed a solely β phase microstructure that resulted from the addition of Zr. The nanotubular structure formed with a diameter of about 200 nm, and the HA/Ti thin film was deposited on the nanotubular structure. The HA/Ti thin film-coated nanotubular Ti-35Nb-xZr alloys showed good corrosion resistance in 0.9% NaCl solution.

  8. The influence of Ti doping and annealing on Ce_2Ti_2O_7 flash memory devices

    International Nuclear Information System (INIS)

    Kao, Chyuan Haur; Chen, Su Zhien; Luo, Yang; Chiu, Wang Ting; Chiu, Shih Wei; Chen, I Chien; Lin, Chan-Yu; Chen, Hsiang

    2017-01-01

    Highlights: • Ce_2Ti_2O_7 flash memories have been fabricated. • Material quality can be improved by annealing. • The memory performance can be enhanced by Ti doping. • Ti doping and annealing can reinforce crystallization. - Abstract: In this research, a CeO_2 film with Ti doping was used as a trapping layer in metal oxide high-K-oxide-Si (MOHOS)-type memory devices. Since incorporation of Ti atoms into the film could fix dangling bonds and defects, the Ce_2Ti_2O_7 trapping layer with annealing treatment could have a larger memory window and a faster programming/erasing speed. To confirm the origin, multiple material analyses indicate that annealing at an appropriate temperature and Ti doping could enhance crystallization. The Ce_2Ti_2O_7-based memory device is promising for future industrial flash memory applications.

  9. High-stability Ti{sup 4+} precursor for the TiO{sub 2} compact layer of dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Yi, Qinghua; Cong, Shan; Wang, Hao; Wang, Yun; Dai, Xiao; Zhao, Jie; Sun, Yinghui; Lou, Yanhui; Zou, Guifu, E-mail: zouguifu@suda.edu.cn

    2015-11-30

    Graphical abstract: - Highlights: • We developed an aqueous polymer-assisted deposition method to improve the chemical stability of the TiCl{sub 4} aqueous solution. • The Ti{sup 4+} is encapsulated by the polymer can maintain their initial performances for several months. • The film is dense, smooth and uniform, preparing by this method. • The power conversion efficiency of the DSSC based on P-TiO{sub 2} compact film is about 12.5% higher than that based on H-TiO{sub 2}. - Abstract: A compact layer (blocking layer) can effectively block the direct contact between the fluorine-doped tin oxide (FTO) glass substrate and electrolyte in dye-sensitized solar cells (DSSCs). The TiCl{sub 4} hydrolysis has been widely adopted for preparing the TiO{sub 2} compact layer (H-TiO{sub 2}). However, the TiCl{sub 4} aqueous solution is unstable for its high reactivity. To improve the chemical stability of TiCl{sub 4} aqueous solution, the Ti{sup 4+} is encapsulated by the polymer, polyethyleneimine (PEI). Experimentals show that the Ti-PEI precursor solution can maintain their initial performances for several months. The resulting TiO{sub 2} film (P-TiO{sub 2}) grown by the Ti-PEI precursor is dense, smooth and uniform without any visible and detectable cracks or voids. The P-TiO{sub 2} compact layer is even denser than the H-TiO{sub 2} compact layer, suggesting reducing the electron recombination and prolonging the electron lifetime in dye-sensitized solar cells. Indeed, the electron lifetime of the DSSC based on the P-TiO{sub 2} is 13.15 ms, which is longer than the 10.83 ms based on H-TiO{sub 2}. Meanwhile, the power conversion efficiency of the DSSC based on P-TiO{sub 2} compact film is about 12.5% higher than that based on H-TiO{sub 2}. Therefore, this encapsulation technology can not only improve the stability of the metal ions solution but also meet a large-scale fabrication demand of the TiO{sub 2} compact layer in future DSSCs.

  10. Microstructure and sound velocity of Ti-N-O synthetic inclusions in Ti-6Al-4V

    International Nuclear Information System (INIS)

    Gigliotti, M.F.X.; Gilmore, R.S.; Perocchi, L.C.

    1994-01-01

    Nitrogen and oxygen stabilize the alpha phase in titanium. Regions within Ti alloy parts containing high local levels of N and O can stabilize a hard-alpha phase. The ultrasonic properties of titanium-nitrogen-oxygen inclusions within Ti-6Al-4V (Ti64) blocks were measured and related to inclusion chemistry. Sound velocities were measured on Ti-N-O alloy samples that had been prepared by powder metallurgy and ingot-melting techniques. The contributions to sound velocity from oxygen and nitrogen contents were determined. Then, Ti64 blocks were hot isostatic pressing (HIP) bonded to contain inclusions of the Ti-N-O alloys. The signal-to-noise ratios of reflections from uncracked inclusions were found to be an increasing function of inclusion interstitial content and were related to changes in sound velocity with inclusion chemistry. Measurements were made of the reflectance of titanium-nitrogen inclusions in titanium and Ti64

  11. Phase composition and tribological properties of Ti-Al coatings produced on pure Ti by laser cladding

    International Nuclear Information System (INIS)

    Guo Baogang; Zhou Jiansong; Zhang Shitang; Zhou Huidi; Pu Yuping; Chen Jianmin

    2007-01-01

    Ti-Al coatings with ∼14.7, 18.1, 25.2 and 29.7 at.% Al contents were fabricated on pure Ti substrate by laser cladding. The laser cladding Ti-Al coatings were analyzed with X-ray diffraction (XRD), scanning electron microscope (SEM) and X-ray energy dispersive spectroscopy (EDS). It was found that with the increase of Al content, the diffraction peaks shifted gradually to higher 2θ values. The laser cladding Ti-Al coatings with 14.7 and 18.1 at.% Al were composed of α-Ti and α 2 -Ti 3 Al phases, while those with 25.2 and 29.7 at.% Al were composed of α 2 -Ti 3 Al phase. With the increase of Al content, the cross-sectional hardness increased, while the fracture toughness decreased. For the laser cladding Ti-Al coatings, when the Al content was ≤18.1 at.%, the wear mechanism was adhesive wear and abrasive wear; while when the Al content ≥25.2 at.%, the wear mechanism was adhesive wear, abrasive wear and microfracture. With the increase of Al content, the wear rate of laser cladding Ti-Al coatings decreased under 1 N normal load, while the wear rate firstly decreased and then increased under a normal load of 3 N. Due to its optimized combination of high hardness and high fracture toughness, the laser cladding Ti-Al coating with 18.1 at.% Al showed the best anti-wear properties at higher normal load

  12. Phase composition and tribological properties of Ti-Al coatings produced on pure Ti by laser cladding

    Energy Technology Data Exchange (ETDEWEB)

    Guo Baogang [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Graduate School, Chinese Academy of Sciences, Beijing 100039 (China); Zhou Jiansong [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Zhang Shitang [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Graduate School, Chinese Academy of Sciences, Beijing 100039 (China); Zhou Huidi [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Pu Yuping [Central Iron and Steel Research Institute, Beijing 100081 (China); Chen Jianmin [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)], E-mail: chenjm@lzb.ac.cn

    2007-10-15

    Ti-Al coatings with {approx}14.7, 18.1, 25.2 and 29.7 at.% Al contents were fabricated on pure Ti substrate by laser cladding. The laser cladding Ti-Al coatings were analyzed with X-ray diffraction (XRD), scanning electron microscope (SEM) and X-ray energy dispersive spectroscopy (EDS). It was found that with the increase of Al content, the diffraction peaks shifted gradually to higher 2{theta} values. The laser cladding Ti-Al coatings with 14.7 and 18.1 at.% Al were composed of {alpha}-Ti and {alpha}{sub 2}-Ti{sub 3}Al phases, while those with 25.2 and 29.7 at.% Al were composed of {alpha}{sub 2}-Ti{sub 3}Al phase. With the increase of Al content, the cross-sectional hardness increased, while the fracture toughness decreased. For the laser cladding Ti-Al coatings, when the Al content was {<=}18.1 at.%, the wear mechanism was adhesive wear and abrasive wear; while when the Al content {>=}25.2 at.%, the wear mechanism was adhesive wear, abrasive wear and microfracture. With the increase of Al content, the wear rate of laser cladding Ti-Al coatings decreased under 1 N normal load, while the wear rate firstly decreased and then increased under a normal load of 3 N. Due to its optimized combination of high hardness and high fracture toughness, the laser cladding Ti-Al coating with 18.1 at.% Al showed the best anti-wear properties at higher normal load.

  13. Material characteristic of Ti alloy (Ti-6Al-4V)

    International Nuclear Information System (INIS)

    Toyoshima, Noboru

    1997-03-01

    In regard to material characteristic of Ti alloy (Ti-6Al-4V), the following matters are provided by experiments. 1) In high temperature permeation behavior of implanted deuterium ion (0.5keV, 6.4 x 10 18 D + ions/m 2 s, ∼760deg K), the ratio of permeation flux to incident flux ranges from 3.3 x 10 -3 at 633deg K to 4.8 x 10 -3 at 753deg K. The activation energy of permeation is 0.12eV in this temperature region above 600deg K. At temperatures below 600deg K, the permeation flux of deuterium decreases drastically and the implanted ions remain in the alloy. 2) Radioactivation analysis using 14MeV fast neutron shows that Ti-6Al-4V alloy contains higher values of principal ingredients, Al, V, Fe, than that recorded at the chemical composition of Ti alloy, and also, contains impurities with Ni, Co and Mn. 3) Fraction of about 0.095wt% H 2 were absorbed in the test specimens, and tensile strength test was carried out. Under the condition of the hydrogen pressure 50 torr and temperature ∼500degC. The results show that there is no degradation in mechanical properties for absorption of with less than 0.04wt% H 2 . The tensile strength of wilding specimens have almost the same as that without wilding. Ti alloy, as a material of vacuum vessel of nuclear fusion device, must be selected to that with less impurities, particularly Co, by radioactivation analysis, and must be used under the temperature of 200-300degC, where hydrogen absorption does not make too progress. It is considered that Ti alloy can be used with less than 0.04wt% H 2 absorption in viewpoint of material mechanical strength. (author)

  14. Ab Initio Study of the Atomic Level Structure of the Rutile TiO2(110)-Titanium Nitride (TiN) Interface.

    Science.gov (United States)

    Gutiérrez Moreno, José Julio; Nolan, Michael

    2017-11-01

    Titanium nitride (TiN) is widely used in industry as a protective coating due to its hardness and resistance to corrosion and can spontaneously form a thin oxide layer when it is exposed to air, which could modify the properties of the coating. With limited understanding of the TiO 2 -TiN interfacial system at present, this work aims to describe the structural and electronic properties of oxidized TiN based on a density functional theory (DFT) study of the rutile TiO 2 (110)-TiN(100) interface model system, also including Hubbard +U correction on Ti 3d states. The small lattice mismatch gives a good stability to the TiO 2 -TiN interface after depositing the oxide onto TiN through the formation of interfacial Ti-O bonds. Our DFT+U study shows the presence of Ti 3+ cations in the TiO 2 region, which are preferentially located next to the interface region as well as the rotation of the rutile TiO 2 octahedra in the interface structure. The DFT+U TiO 2 electronic density of states (EDOS) shows localized Ti 3+ defect states forming in the midgap between the top edge of the valence and the bottom of the conduction band. We increase the complexity of our models by the introduction of nonstoichiometric compositions. Although the vacancy formation energies for Ti in TiN (E vac (Ti) ≥ 4.03 eV) or O in the oxide (E vac (O) ≥ 3.40 eV) are quite high relative to perfect TiO 2 -TiN, defects are known to form during the oxide growth and can therefore be present after TiO 2 formation. Our results show that a structure with exchanged O and N can lie 0.82 eV higher in energy than the perfect system, suggesting the stability of structures with interdiffused O and N anions at ambient conditions. The presence of N in TiO 2 introduces N 2p states localized between the top edge of the O 2p valence states and the midgap Ti 3+ 3d states, thus reducing the band gap in the TiO 2 region for the exchanged O/N interface EDOS. The outcomes of these simulations give us a most comprehensive

  15. Structural evolution and formation mechanisms of TiC/Ti nanocomposites prepared by high-energy mechanical alloying

    International Nuclear Information System (INIS)

    Gu Dongdong; Meiners, Wilhelm; Hagedorn, Yves-christian; Wissenbach, Konrad; Poprawe, Reinhart

    2010-01-01

    In this work, high-energy ball milling of a micrometre-scaled Ti and TiC powder mixture was performed to prepare TiC/Ti nanocomposites. The constituent phases and microstructural characteristics of the milled powders were studied by an x-ray diffractometer, a scanning electron microscope, an energy dispersive x-ray spectroscope and a transmission electron microscope. Formation mechanisms and theoretical basis of the microstructural development were elucidated. It showed that on increasing the applied milling time, the structures of the Ti constituent experienced a successive change from hcp (5 h) to fcc (10 h) and finally to an amorphous state (≥15 h). The hydrostatic stresses caused by the excess free volume at grain boundaries were calculated to be 3.96 and 5.59 GPa for the Ti constituent in 5 and 10 h milled powders, which was responsible for the hcp to fcc polymorphic change. The amorphization of Ti constituent was due to the large defect concentration induced by severe plastic deformation during milling. The milled powder particles underwent two stages of significant refinement at 10 and 20 h during milling. For a higher milling time above 25 h, powder characteristics and chemical compositions became stable. The competitive action and the final equilibrium between the mechanisms of fracturing and cold welding accounted for the microstructural evolution. The ball milled products were typically nanocomposite powders featured by a nanocrystalline/amorphous Ti matrix reinforced with uniformly dispersed TiC nanoparticles. The finest crystalline sizes of the Ti and TiC constituents were 17.2 nm (after 10 h milling) and 13.5 nm (after 20 h milling), respectively.

  16. Modeling creep deformation of a two-phase TiAI/Ti3Al alloy with a lamellar microstructure

    Science.gov (United States)

    Bartholomeusz, Michael F.; Wert, John A.

    1994-10-01

    A two-phase TiAl/Ti3Al alloy with a lamellar microstructure has been previously shown to exhibit a lower minimum creep rate than the minimum creep rates of the constituent TiAl and Ti3Al single-phase alloys. Fiducial-line experiments described in the present article demonstrate that the creep rates of the constituent phases within the two-phase TiAl/Ti3Al lamellar alloy tested in compression are more than an order of magnitude lower than the creep rates of single-phase TiAl and Ti3Al alloys tested in compression at the same stress and temperature. Additionally, the fiducial-line experiments show that no interfacial sliding of the phases in the TiAl/Ti3Al lamellar alloy occurs during creep. The lower creep rate of the lamellar alloy is attributed to enhanced hardening of the constituent phases within the lamellar microstructure. A composite-strength model has been formulated to predict the creep rate of the lamellar alloy, taking into account the lower creep rates of the constituent phases within the lamellar micro-structure. Application of the model yields a very good correlation between predicted and experimentally observed minimum creep rates over moderate stress and temperature ranges.

  17. Revision of the Ge–Ti phase diagram and structural stability of the new phase Ge{sub 4}Ti{sub 5}

    Energy Technology Data Exchange (ETDEWEB)

    Bittner, Roland W. [University of Vienna, Department of Inorganic Chemistry/Materials Chemistry, Währingerstraße 42, 1090 Wien (Austria); Colinet, Catherine [Science et Ingénierie des Matériaux et Procédés, Grenoble INP, UJF, CNRS, 38402 Saint Martin d’Hères Cedex (France); Tedenac, Jean-Claude [Institut de Chimie Moléculaire et des Matériaux I.C.G., UMR-CNRS 5253, Université Montpellier II, Place E. Bataillon, 34095 Montpellier Cedex 5 (France); Richter, Klaus W., E-mail: klaus.richter@univie.ac.at [University of Vienna, Department of Inorganic Chemistry/Materials Chemistry, Währingerstraße 42, 1090 Wien (Austria)

    2013-11-15

    Highlights: •New compound Ge{sub 4}Ti{sub 5} found by experiments and by DFT ground state calculations. •Enthalpies of formation calculated for different Ge–Ti compounds. •Modifications of the Ge–Ti phase diagram suggested. -- Abstract: The binary phase diagram Ge–Ti was investigated experimentally by powder X-ray diffraction, scanning electron microscopy including EDX analysis, and differential thermal analysis. Total energies of the compounds GeTi{sub 3}, GeTi{sub 2}, Ge{sub 3}Ti{sub 5}, Ge{sub 4}Ti{sub 5}, Ge{sub 5}Ti{sub 6}, GeTi and Ge{sub 2}Ti were calculated for various structure types employing electronic density-functional theory (DFT). Experimental studies as well as electronic calculations show the existence of a new phase Ge{sub 4}Ti{sub 5} (Ge{sub 4}Sm{sub 5}-type, oP36, Pnma) which is formed in a solid state reaction Ge{sub 3}Ti{sub 5} + Ge{sub 5}Ti{sub 6} = Ge{sub 4}Ti{sub 5}. In addition, a significant homogeneity range was observed for the compound Ge{sub 3}Ti{sub 5} and the composition of the liquid phase in the eutectic reaction L = Ge + Ge{sub 2}Ti was found to be at significant higher Ge-content (97.5 at.% Ge) than reported in previous studies. Based on these new results, a modified phase diagram Ge–Ti is suggested. The zero-temperature lattice parameters and the formation enthalpies determined by DTF calculations were found to be in good agreement with experimental data.

  18. Solid solution cermet: (Ti,Nb)(CN)-Ni cermet.

    Science.gov (United States)

    Kwon, Hanjung; Jung, Sun-A

    2014-11-01

    Solid solution powders without W, (Ti,Nb)(CN) powders with a B1 structure (NaCl like), were synthesized by high energy milling and carbothermal reduction in nitrogen. The range of molar ratios of Ti/Nb for forming complete (Ti,Nb)(CN) phase was broader than that of Ti/W for the (Ti,W)(CN) phase because carbide or carbonitride of Nb had a B1 crystal structure identical to Ti(CN) while WC had a hexagonal crystal structure. The results revealed that the hardness of (Ti,Nb)(CN)-Ni cermets was higher than that of (Ti,W)(CN)-Ni cermets. The lower density of the (Ti,Nb)(CN) powder contributed to the higher hardness compared to (Ti,W)(CN) because the volumetric ratio of (Ti,Nb)(CN) in the (Ti,Nb)(CN)-Ni cermets was higher than that of (Ti,Nb)(CN) in the (Ti,W)(CN)-Ni cermets at the same weight ratio of Ni. Additionally, it was assumed that intrinsic the properties of (Ti,Nb)(CN) could also be the cause for the high hardness of the (Ti,Nb)(CN)-Ni cermets.

  19. Facile synthesis of the Ti3+ self-doped TiO2-graphene nanosheet composites with enhanced photocatalysis.

    Science.gov (United States)

    Qiu, Bocheng; Zhou, Yi; Ma, Yunfei; Yang, Xiaolong; Sheng, Weiqin; Xing, Mingyang; Zhang, Jinlong

    2015-02-26

    This study developed a facile approach for preparing Ti(3+) self-doped TiO2-graphene photocatalyst by a one-step vacuum activation technology involved a relative lower temperature, which could be activated by the visible light owing to the synergistic effect among Ti(3+) doping, some new intersurface bonds generation and graphene oxide reduction. Compared with the traditional methods, the vacuum activation involves a low temperature and low-costing, which can achieve the reduction of GO, the self doping of Ti(3+) in TiO2 and the loading of TiO2 nanoparticles on GR surface at the same time. These resulting TiO2-graphene composites show the high photodegradation rate of MO, high hydrogen evolution activity and excellent IPCE in the visible light irradiation. The facile vacuum activation method can provide an effective and practical approach to improve the performance of TiO2-graphene and other metal oxides-graphene towards their practical photocatalytic applications.

  20. Influence of (TiC+TiB) on the microstructure and tensile properties of Ti-B20 matrix alloy

    Energy Technology Data Exchange (ETDEWEB)

    Rahoma, H.K.S. [National Key Laboratory of Science and Technology on Precision Heat Processing of Metals, Harbin Institute of Technology, Harbin 150001 (China); Chen, Y.Y., E-mail: yychen@hit.edu.cn [National Key Laboratory of Science and Technology on Precision Heat Processing of Metals, Harbin Institute of Technology, Harbin 150001 (China); State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Wang, X.P.; Xiao, S.L. [National Key Laboratory of Science and Technology on Precision Heat Processing of Metals, Harbin Institute of Technology, Harbin 150001 (China)

    2015-04-05

    Highlights: • After forging, the microstructure was significantly refined and uniform. • The presence of carbide and boride also led to uniform and finer precipitation of α during aging as compared to the matrix alloy. • The size of secondary α phase increased with the increase of aging temperature. This trend leads to the decrease of strength and the increase of ductility. - Abstract: A hybrid of (TiB+TiC) reinforced beta titanium matrix (Ti-B20) were produced by non-consumable arc-melting technology and hot-forging. Microstructures of the composites were observed by optical microscopy (OM), transmission electron microscope (TEM) and scanning electron microscopy (SEM). The results show that both the TiB whiskers and TiC particles tend to segregate at β boundaries. The β grain size and secondary α lath width are refined by reinforcements and aging treatment. Evolution of tensile properties shows that enhancement in yield strength and ultimate tensile strength with the addition of reinforcements, as well as the remarkable increase in the ductility can be attributed to aging treatment at 600 °C and 650 °C. The size of secondary α phase increased with the increase of aging temperature. This trend leads to the decrease of strength and the increase of ductility to get good balance of properties. The fracture mechanism of the composite can be attributed to the cracking of the reinforcements.

  1. Adhesive and tribocorrosive behavior of TiAlPtN/TiAlN/TiAl multilayers sputtered coatings over CoCrMo

    Science.gov (United States)

    Canto, C. E.; Andrade, E.; Rocha, M. F.; Alemón, B.; Flores, M.

    2017-09-01

    The tribocorrosion resistance and adherence of multilayer coatings of TiAlPtN/TiAlN/TiAl synthesized by PVD reactive magnetron sputtering over a CoCrMo alloy substrate in 10 periods of 30 min each were analyzed and compared to those of the substrate alone and to that of a TiAlPtN single layer coating of the same thickness. The objective of the present work was to create multilayers with different amounts of Pt in order to enhance the tribocorrosion resistance of a biomedical alloy of CoCrMo. Tribocorrosion tests were performed using Simulated Body Fluid (SBF) at typical body temperature with a tribometer in a pin on disk test. The elemental composition and thickness of the coating which behave better at the tribocorrosion tests were evaluated by means of RBS (Rutherford Backscattering Spectroscopy) IBA (Ion Beam Analysis) technique, using an alpha particles beam of 1.8 MeV, before and after the reciprocating motion in the tribocorrosion test. In order to simulate the elemental profile of the samples, the SIMNRA simulation computer code was used. Measurements of the adhesion of the coatings to the substrate were carried on by means of a scratch test using a tribometer. By taking micrographs of the produced tracks, the critical loads at which the coatings are fully separated from the substrate were determined. From these tests it was observed that a coating with 10 min of TiAlPtN in a TiAlPtN/TiAl period of 30 min in multilayers of 10 periods and with an average thickness of 145 nm for the TiAlPtN nanolayers had the best tribocorrosion resistance behavior, compared to that of the CoCrMo alloy. The RBS experiments showed a reduction of the thickness of the films along with some loss of the multilayer structure after the reciprocating motion. The adhesion tests indicated that the multilayer with the average TiAlPtN thickness of 145 nm displayed the highest critical load. These results indicate a high correlation between the adherence and the tribocorrosion behavior.

  2. Effect of Ti concentration on the structure and texture of SiTiOC glasses

    International Nuclear Information System (INIS)

    Tellez, L.; Rubio, J.; Valenzuela, M.A.; Rubio, F.; Oteo, J.L.

    2009-01-01

    Five different silicon-titanium organic-inorganic hybrid materials were prepared by the reaction of tetraethoxysilane, titanium tetrabutoxide and silanol-terminated polydimethylsiloxane. Si-Ti oxycarbide glasses were prepared by pyrolysis of the hybrid materials in nitrogen atmosphere in the range of 400 to 1500 deg. C. The obtained Si-Ti oxycarbide materials were characterized by Fourier Transform-Infra Red spectroscopy, X-ray-diffraction, mercury porosimetry and SEM. The study indicated that the reactivity towards water increases up to 1000 deg. C, at higher temperatures it decreases for all samples. During the pyrolysis, Ti atoms were incorporated into the silicate network leading to the formation of Si-Ti oxycarbide glasses, except with sample containing 7% of Ti which presented also the formation of β-SiC and TiC crystalline phases. The porosity was increased up to 600 deg. C and then decreased tending to disappear at 1500 deg. C. When the titanium concentration increased from 1 to 3% in the oxycarbide glass, the porosity decreased; for higher concentration, an increase in the porosity was observed.

  3. Effect of Ti concentration on the structure and texture of SiTiOC glasses

    Energy Technology Data Exchange (ETDEWEB)

    Tellez, L. [Dpt. Ing. Metalurgica. ESIQIE-Instituto Politecnico Nacional. Zacatenco, 07738 Mexico D.F. (Mexico); Rubio, J. [Instituto de Ceramica y Vidrio. C.S.I.C. Campus de la Universidad Autonoma de Madrid, Canto Blanco 28049, Madrid (Spain); Valenzuela, M.A., E-mail: mavalenz@ipn.mx [Lab. Catalisis y Materiales, ESIQIE-Instituto Politecnico Nacional. Zacatenco, 07738 Mexico D.F. (Mexico); Rubio, F.; Oteo, J.L. [Instituto de Ceramica y Vidrio. C.S.I.C. Campus de la Universidad Autonoma de Madrid, Canto Blanco 28049, Madrid (Spain)

    2009-06-15

    Five different silicon-titanium organic-inorganic hybrid materials were prepared by the reaction of tetraethoxysilane, titanium tetrabutoxide and silanol-terminated polydimethylsiloxane. Si-Ti oxycarbide glasses were prepared by pyrolysis of the hybrid materials in nitrogen atmosphere in the range of 400 to 1500 deg. C. The obtained Si-Ti oxycarbide materials were characterized by Fourier Transform-Infra Red spectroscopy, X-ray-diffraction, mercury porosimetry and SEM. The study indicated that the reactivity towards water increases up to 1000 deg. C, at higher temperatures it decreases for all samples. During the pyrolysis, Ti atoms were incorporated into the silicate network leading to the formation of Si-Ti oxycarbide glasses, except with sample containing 7% of Ti which presented also the formation of {beta}-SiC and TiC crystalline phases. The porosity was increased up to 600 deg. C and then decreased tending to disappear at 1500 deg. C. When the titanium concentration increased from 1 to 3% in the oxycarbide glass, the porosity decreased; for higher concentration, an increase in the porosity was observed.

  4. Corrosion behavior of TiN, TiAlN, TiAlSiN thin films deposited on tool steel in the 3.5 wt.% NaCl solution

    International Nuclear Information System (INIS)

    Yoo, Yun Ha; Le, Diem Phuong; Kim, Jung Gu; Kim, Sun Kyu; Vinh, Pham Van

    2008-01-01

    TiN, TiAlN and TiAlSiN hard coatings were deposited onto AISI H13 tool steel by cathodic arc plasma method. X-ray diffraction (XRD) analysis confirmed that incorporation of Al and Si into TiN led to refinement of microstructure. From the results of potentiodynamic polarization test and electrochemical impedance spectroscopy (EIS) test conducted in an aerated 3.5% NaCl solution, the TiAlSiN film showed the best corrosion resistance with the lowest corrosion current density and porosity, the highest protective efficiency and total resistance (pore resistance plus charge transfer resistance)

  5. Morphological evolution of primary TiC carbide in laser clad TiC reinforced FeAl intermetallic composite coating

    Institute of Scientific and Technical Information of China (English)

    陈瑶; 王华明

    2003-01-01

    The novel rapidly solidified TiC/FeAl composite coatings were fabricated by laser cladding on the substrate of 1Cr18Ni9Ti stainless steel, particular emphasis has been placed on the growth morphologies of TiC carbide and its growth mechanism under a constant solidification conditions. Results show that the growth morphology of TiC carbide strongly depends upon the nucleation process and mass transportation process of TiC forming elements in laser melt pool. With increasing amount of titanium and carbon in melt pool, the growth morphology of TiC carbide changes from block-like to star-like and well-developed dendrite. As the amount of titanium and carbon increases further, TiC carbide particles are found to be irregular polyhedral block. Although the growth morphologies of TiC are various,their advancing fronts are all faceted, illustrating that TiC carbide grows by the mechanism of lateral ledge growth.

  6. Tailoring ultrafine grained and dispersion-strengthened Ti2AlC/TiAl ...

    Indian Academy of Sciences (India)

    and Ti-Al pre-alloyed powders at low temperature of 1150◦C. The composite mainly consisted ... Metal–matrix composites; mechanical properties; microstructures; sintering. 1. Introduction γ-TiAl-based intermetallic alloys have been extensively.

  7. Ti-Mg alloy powder synthesis via mechanochemical reduction of TiO 2 by elemental magnesium

    CSIR Research Space (South Africa)

    Mushove, T

    2009-04-01

    Full Text Available This paper reports the preliminary results of an investigation on the synthesis of a Ti-Mg alloy powder through mechanochemical processing of TiO 2 and Mg powders. TiO 2 was mixed with elemental Mg according to a nominal stoichiometric composition...

  8. Ti2Al(C, N) Solid Solution Reinforcing TiAl-Based Composites: Evolution of a Core-Shell Structure, Interfaces, and Mechanical Properties.

    Science.gov (United States)

    Song, Xiaojie; Cui, Hongzhi; Han, Ye; Ding, Lei; Song, Qiang

    2018-05-16

    In this work, Ti 2 Al(C, N) solid solution with lamellar structure-enhanced TiAl matrix composites was synthesized by vacuum arc melting, using bulk g-C 3 N 4 , Ti, and Al powders as raw materials. The phases, microstructures, interfaces, and mechanical properties were investigated. MAX phase of Ti 2 Al(C, N) solid solution with lamellar structure was formed. During the melting process, first, C 3 N 4 reacted with Ti to form Ti(C, N) by Ti + C 3 N 4 → Ti(C, N). Then Ti 2 Al(C, N) was formed by a peritectic reaction of TiAl(l) + Ti(C, N)(s) → Ti 2 Al(C, N). C 3 N 4 is the single reactant that provides C and N simultaneously to final product of Ti 2 Al(C, N). The interfaces of TiAl//Ti 2 Al(C, N) and Ti 2 Al(C, N)//Ti(C, N) display perfect orientation relationships with low misfit values. The microhardness, compressive strength, and strain of best-performing TiAl-10 mol % Ti 2 Al(C, N) composite were improved by 45%, 55.7%, and 50% compared with the TiAl alloy, respectively. Uniformly distributed Ti 2 Al(C, N) and unreacted Ti(C, N) particles contributed to the grain refinement and reinforcement of the TiAl matrix. Laminated tearing, particle pull-out, and the crack-arresting of Ti 2 Al(C, N) are crucial for the improvement in compressive strength and plasticity of the composites.

  9. Formation Mechanism and Dispersion of Pseudo-Tetragonal BaTiO3-PVP Nanoparticles from Different Titanium Precursors: TiCl4 and TiO2

    Directory of Open Access Journals (Sweden)

    Jinhui Li

    2017-12-01

    Full Text Available Nano-sized tetragonal BaTiO3 (BT particles that are well dispersed in solution are essential for the dielectric layer in multilayer ceramic capacitor technology. A hydrothermal process using TiCl4 and BaCl2, as source of Ti and Ba, respectively, or the precursor TiO2 as seed for the formation of BT, and poly(vinylpyrrolidone (PVP as a surfactant, was employed in this study to enhance both the dispersibility and tetragonality (c/a simultaneously in a single reaction process. The process parameters, i.e., the ratio of TiO2 substitution of TiCl4, the reaction time, and PVP content were systematically studied, and the growth mechanism and relation between the tetragonality and the particle size are discussed. Dynamic light scattering (DLS analysis was used to show that truncated pseudo-tetragonal BT-PVP particles with an average size of 100 nm, having a narrow size distribution and a coefficient of variation (CV as low as 20% and being mono-dispersed in water, were produced. The narrow particle size distribution is attributed to the ability of PVP to inhibit the growth of BT particles, and the high c/a of BT-PVP to heterogeneous particle growth using TiO2 seeds.

  10. Concentration of uranium on TiO-PAN and NaTiO-PAN composite absorbers

    International Nuclear Information System (INIS)

    Motl, Alois; Sebesta, Ferdinand; John, Jan; Spendlikova, Irena; Nemec, Mojmir

    2013-01-01

    Inorganic ion exchangers have been extensively tested for use in separation and concentration of uranium from Surface water. Except for separation of uranium from uranium -Contaminated waste water (e.g. waste water from mining and milling of uranium, Waste from nuclear fuel reprocessing) their main area of application has been foreseen to be their use for extraction of uranium from sea water which could partially cover future needs of uranium. Another perspective area of application is pre-concentration of uranium from natural waters followed by uranium determination via various specialized techniques such as TRLFS or AMS. Possibilities of uranium extraction from sea water have been subject of several international conferences (e.g. Topical meetings on the Recovery of Uranium from Seawater in 1980's, ACS National Meetings 2012 etc.) and are critically evaluated in a review by Bitte or recently by Kim. In the Czech Republic uranium-selective inorganic ion exchangers might be applied for treatment of various wastes from uranium industry, namely underground Water, uranium milling over-balance water, or acid waste water from underground uranium leaching and also like in other countries for determination of uranium isotopic composition focusing on anthropogenic and natural 236 U content. Among the best performing inorganic ion exchangers for the above listed purposes hydrated titanium dioxide (abbreviated as TiO) and sodium titanate (abbreviated as NaTiO) can be listed. Properties of TiO and NaTiO were reviewed by Lehto. From the point of view of ion-exchange, properties of hydrated titanium oxide and sodium titanate are very similar. The main disadvantage of these ion exchangers for industrial-scale application is their insufficient mechanical stability. To improve this property, the sorption materials can be embedded into a binding matrix. Modified polyacrylonitrile (PAN) has been proposed at the Czech Technical University in Prague as a universal binding matrix for

  11. Effect of Zirconium Addition on Microstructure and Mechanical Property of TiC/Ti6A14V Composites

    Science.gov (United States)

    Ma, Xuliang; Wang, Xiang; Li, Li; Gai, Pengtao; Zhu, Chengwu

    TiC/Ti6A14V composites with different Zr additions were prepared successfully in a consumable vacuum arc furnace equipped with a water-cooled copper crucible and the effect of the Zr content on the microstructure and mechanical property of 15 vol.%TiC/Ti6A14V composites was investigated by XRD, SEM and hardness testing. The results show that when the level of Zr addition is less than 4 wt.%, the morphology of the primary TiC in the composites is dendrite, and the petal-shape, piece-shape or palpus-shape eutectic TiC separates out around the primary TiC. The average size of the primary TiC decreases and the amount of eutectic TiC increases gradually with increasing Zr content. The effects of Zr on morphology of the primary TiC weaken with further addition of Zr. And the hardness (HRC) of composites was obviously increased in the whole range of Zr addition. The refinement mechanism of Zr was attributed to the combined effects of increase in nucleation rate at the constitutionally supercooled zone ahead of the solidification front and reduction in growth rate.

  12. In situ synthesis of Ti{sub 2}AlC–Al{sub 2}O{sub 3}/TiAl composite by vacuum sintering mechanically alloyed TiAl powder coated with CNTs

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jian [Department of Materials Science and Engineering of Tianjin University, Tianjin Key Laboratory of Composite and Functional Materials, Tianjin 300072 (China); Zhao, Naiqin, E-mail: nqzhao@tju.edu.cn [State Key Laboratory of Hydraulic Engineering Simulation and Safety, Tianjin (China); Department of Materials Science and Engineering of Tianjin University, Tianjin Key Laboratory of Composite and Functional Materials, Tianjin 300072 (China); Nash, Philip [Thermal Processing Technology Center, Illinois Institute of Technology, IL (United States); Liu, Enzuo; He, Chunnian; Shi, Chunsheng; Li, Jiajun [Department of Materials Science and Engineering of Tianjin University, Tianjin Key Laboratory of Composite and Functional Materials, Tianjin 300072 (China)

    2013-11-25

    Highlights: •Using zwitterionic surfactant to enhance the dispersion of the CNTs on the powder surface. •CNTs as carbon source decreased the formation temperature of Ti{sub 2}AlC. •Al{sub 2}O{sub 3} was generated in situ from the oxygen atoms introduced in the drying procedure. •Nanosized Ti{sub 3}Al was precipitated at 1250 °C and distribute in the TiAl matrix homogeneously. •Ti{sub 2}AlC–Al{sub 2}O{sub 3}/TiAl composite was synthesized in situ by sintering pre-alloy Ti–Al coated with CNTs. -- Abstract: Bulk Ti{sub 2}AlC–Al{sub 2}O{sub 3}/TiAl composites were in situ synthesized by vacuum sintering mechanically alloyed Ti–50 at.% Al powders coated with carbon nanotubes (CNTs). The pre-alloyed Ti–50 at.% Al powder was obtained by ball milling Ti and Al powders. The multi-walled carbon nanotubes as the carbon resource were covered on the surface of the pre-alloyed powders by immersing them into a water solution containing the CNTs. A zwitterionic surfactant was used to enhance the dispersion of the CNTs on the powder surface. The samples were cold pressed and sintered in vacuum at temperatures from 950 to 1250 °C, respectively. The results show that the reaction of forming Ti{sub 2}AlC can be achieved below 950 °C, which is 150 °C lower than in the Ti–Al–TiC system and 250 °C lower than for the Ti–Al–C system due to the addition of CNTs. Additionally, the reinforcement of Al{sub 2}O{sub 3} particles was introduced in situ in Ti{sub 2}AlC/TiAl by the drying process and subsequent sintering of the composite powders. Dense Ti{sub 2}AlC–Al{sub 2}O{sub 3}/TiAl composites were obtained by sintering at 1250 °C and exhibited a homogeneous distribution of Ti{sub 2}AlC, Al{sub 2}O{sub 3} and precipitated Ti{sub 3}Al particles and a resulting high hardness.

  13. Ferroelectric BaTiO3 thin films on Ti substrate fabricated using pulsed-laser deposition.

    Science.gov (United States)

    He, J; Jiang, J C; Liu, J; Collins, G; Chen, C L; Lin, B; Giurgiutiu, V; Guo, R Y; Bhalla, A; Meletis, E I

    2010-09-01

    We report on the fabrication of ferroelectric BaTiO3 thin films on titanium substrates using pulsed laser deposition and their microstructures and properties. Electron microscopy studies reveal that BaTiO3 films are composed of crystalline assemblage of nanopillars with average cross sections from 100 nm to 200 nm. The BaTiO3 films have good interface structures and strong adhesion with respect to Ti substrates by forming a rutile TiO2 intermediate layer with a gradient microstructure. The room temperature ferroelectric polarization measurements show that the as-deposited BTO films possess nearly the same spontaneous polarization as the bulk BTO ceramics indicating formation of ferroelectric domains in the films. Successful fabrication of such ferroelectric films on Ti has significant importance for the development of new applications such as structural health monitoring spanning from aerospace to civil infrastructure. The work can be extended to integrate other ferroelectric oxide films with various promising properties to monitor the structural health of materials.

  14. Microstructure and electrochemical characterization of laser melt-deposited Ti2Ni3Si/NiTi intermetallic alloys

    International Nuclear Information System (INIS)

    Dong Lixin; Wang Huaming

    2008-01-01

    Corrosion and wear resistant Ti 2 Ni 3 Si/NiTi intermetallic alloys with Ti 2 Ni 3 Si as the reinforcing phase and the ductile NiTi as the toughening phase were designed and fabricated by the laser melt-deposition manufacturing process. Electrochemical behavior of the alloys was investigated using potentiodynamic polarization testing and electrochemical impedance spectroscopy in an NaOH solution. The results showed that the alloys have outstanding corrosion resistance due to the formation of a protective passive surface film of Ni(OH) 2 as well as the high chemical stability and strong inter-atomic bonds inherent to Ti 2 Ni 3 Si and NiTi intermetallics. The Ti 2 Ni 3 Si content has a significant influence on the microstructure of the alloys but only a slight effect on electrochemical corrosion properties

  15. Studies on the sedimentation and agglomeration behavior of Al-Ti-B and Al-Ti-C grain refiners

    Energy Technology Data Exchange (ETDEWEB)

    Gazanion, F.; Chen, X.G.; Dupuis, C. [Alcan International Ltd., Jonquiere, PQ (Canada). Arvida Research and Development Centre

    2002-07-01

    The sedimentation and agglomeration behavior of Al-Ti-B and Al-Ti-C grain refiners in liquid aluminum has been investigated using the LiMCA and PoDFA analysis techniques in combination with metallographic examination. The widely used Al-5%Ti-1%B and Al-3%Ti-0.15%C master alloys were chosen. Two aluminum alloys, an AAlxxx (commercially pure metal) and an AA5182 (Al-4.5%Mg) alloy, were prepared with different additions of grain refiners. The difference in particle behavior in liquid aluminum for both refiners is described and briefly analyzed in terms of sensitivity to agglomeration and grain refiner performance. Experimental results indicate that, in comparison with the Al-Ti-B refiner, the Al-Ti-C refiner is detrimentally affected by long holding periods due to the decomposition of TiC particles within the melt. (orig.)

  16. My Experience with Ti-Ni-Based and Ti-Based Shape Memory Alloys

    Science.gov (United States)

    Miyazaki, Shuichi

    2017-12-01

    The present author has been studying shape memory alloys including Cu-Al-Ni, Ti-Ni-based, and Ni-free Ti-based alloys since 1979. This paper reviews the present author's research results for the latter two materials since 1981. The topics on the Ti-Ni-based alloys include the achievement of superelasticity in Ti-Ni alloys through understanding of the role of microstructures consisting of dislocations and precipitates, followed by the contribution to the development of application market of shape memory effect and superelasticity, characterization of the R-phase and monoclinic martensitic transformations, clarification of the basic characteristics of fatigue properties, development of sputter-deposited shape memory thin films and fabrication of prototypes of microactuators utilizing thin films, development of high temperature shape memory alloys, and so on. The topics of Ni-free Ti-based shape memory alloys include the characterization of the orthorhombic phase martensitic transformation and related shape memory effect and superelasticity, the effects of texture, omega phase and adding elements on the martensitic transformation and shape memory properties, clarification of the unique effects of oxygen addition to induce non-linear large elasticity, Invar effect and heating-induced martensitic transformation, and so on.

  17. NiTiCu/AlN/NiTiCu shape memory thin film heterostructures for vibration damping in MEMS

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, Navjot; Kaur, Davinder, E-mail: dkaurfph@iitr.ernet.in

    2014-03-25

    Highlights: • Fabrication of NiTiCu/AlN/NiTiCu heterostructure using dc/rf magnetron sputtering. • Exhibits highest hardness (38 GPa) and elastic modulus (187 GPa). • Enhanced dissipation of mechanical energy (E{sub d} = 5.7 N J). • High damping capacity (0.052) and figure of merit (∼0.62). • Can be applied for vibration damping in MEMS. -- Abstract: Shape memory alloy (NiTiCu) thin films coupled with piezoelectric AlN layer produce an intelligent material for vibration damping. In the present study pure NiTiCu, NiTiCu/AlN and NiTiCu/AlN/NiTiCu heterostructures have been deposited on Si substrate using magnetron sputtering technique. By the use of the interfaces and shape memory effect provided by NiTiCu layers, the damping capacity can be increased along with increase in stiffness and mechanical hardness. The heterostructures were characterized in terms of structural, electrical, morphological and mechanical properties by X-ray diffraction (XRD), four probe resistivity method, atomic force microscopy, field emission scanning electron microscopy, and nanoindentation. The NiTiCu/AlN/NiTiCu heterostructure exhibit enhanced mechanical and damping properties as compared to NiTiCu/AlN and pure NiTiCu. This enhancement in hardness and damping of the heterostructure could be attributed to the shape memory effect of NiTiCu, intrinsic piezoelectricity of AlN and increased number of interfaces in heterostructure that help in dissipation of mechanical vibrations. The findings of this work provide additional impetus for the application of these heterostructures in emerging fields of nanotechnology and microelectro mechanical (MEMS) devices.

  18. NiTiCu/AlN/NiTiCu shape memory thin film heterostructures for vibration damping in MEMS

    International Nuclear Information System (INIS)

    Kaur, Navjot; Kaur, Davinder

    2014-01-01

    Highlights: • Fabrication of NiTiCu/AlN/NiTiCu heterostructure using dc/rf magnetron sputtering. • Exhibits highest hardness (38 GPa) and elastic modulus (187 GPa). • Enhanced dissipation of mechanical energy (E d = 5.7 N J). • High damping capacity (0.052) and figure of merit (∼0.62). • Can be applied for vibration damping in MEMS. -- Abstract: Shape memory alloy (NiTiCu) thin films coupled with piezoelectric AlN layer produce an intelligent material for vibration damping. In the present study pure NiTiCu, NiTiCu/AlN and NiTiCu/AlN/NiTiCu heterostructures have been deposited on Si substrate using magnetron sputtering technique. By the use of the interfaces and shape memory effect provided by NiTiCu layers, the damping capacity can be increased along with increase in stiffness and mechanical hardness. The heterostructures were characterized in terms of structural, electrical, morphological and mechanical properties by X-ray diffraction (XRD), four probe resistivity method, atomic force microscopy, field emission scanning electron microscopy, and nanoindentation. The NiTiCu/AlN/NiTiCu heterostructure exhibit enhanced mechanical and damping properties as compared to NiTiCu/AlN and pure NiTiCu. This enhancement in hardness and damping of the heterostructure could be attributed to the shape memory effect of NiTiCu, intrinsic piezoelectricity of AlN and increased number of interfaces in heterostructure that help in dissipation of mechanical vibrations. The findings of this work provide additional impetus for the application of these heterostructures in emerging fields of nanotechnology and microelectro mechanical (MEMS) devices

  19. Reactive magnetron sputtering model at making Ti-TiOx coatings

    International Nuclear Information System (INIS)

    Luchkin, A G; Kashapov, N F

    2014-01-01

    Mathematical model of reactive magnetron sputtering for plant VU 700-D is described. Approximating curves for experimental current-voltage characteristic for two gas input schemas are shown. Choice of gas input schema influences on model parameters (mainly on pumping speed). Reactive magnetron sputtering model allows develop technology of Ti - TiO x coatings deposition without changing atmosphere and pressure in vacuum chamber

  20. Microstructure of two phases alloy Al3Ti/Al3Ti0.75Fe0.25

    International Nuclear Information System (INIS)

    Angeles, C.; Rosas, G.; Perez, R.

    1998-01-01

    The titanium-aluminium system presents three intermetallic compounds from those Al 3 Ti is what less attention has received. The objective of this work is to generate and characterize the microstructure of multiphase alloys nearby to Al 3 Ti compound through Fe addition as alloying. This is because it has been seen that little precipitates of Al 2 Ti phase over Al 3 Ti intermetallic compound increases its ductility. (Author)

  1. First-principles calculations of vacancy effects on structural and electronic properties of TiCx and TiNx

    International Nuclear Information System (INIS)

    Dridi, Z.; Bouhafs, B.; Ruterana, P.; Aourag, H.

    2002-01-01

    First-principles calculations have been used to study the effect of vacancies on the structural and electronic properties in substoichiometric TiC x and TiN x . The effect of vacancies on equilibrium volumes, bulk moduli, electronic band structures and density of states of the substoichiometric phases was studied using a full-potential linear augmented plane-wave method. A model structure of eight-atom supercells with ordered vacancies within the carbon and nitrogen sublattices is used. We find that the lattice parameters of the studied stoichiometries in both TiC x and TiN x are smaller than that of ideal stoichiometric TiC and TiN. Our results for the variation of the lattice parameters and the bulk moduli for TiC x are found to be in good agreement with experiment. The variation of the energy gaps with the atomic concentration ratio shows that these compounds present the same trends. Results for TiC x are compared to a recent full-potential calculation with relaxed 16-atom supercells

  2. First NMR observation of 47Ti and 49Ti in cyclopentadienyl complexes

    International Nuclear Information System (INIS)

    Dormond, A.; Fauconet, M.; Leblanc, J.C.; Moise, C.

    1984-01-01

    47 Ti and 49 Ti NMR spectra of some mono and biscyclopentadienyl complexes are reported for the first time. The resonances span a relatively large range: electron donating substituents on the cyclopentadienyl ring cause an unexpected downfield shift. (author)

  3. Enhancement of Ti-containing hydrogenated carbon (Ti-C:H) films by high-power plasma-sputtering

    International Nuclear Information System (INIS)

    Gwo, Jyh; Chu, Chun-Lin; Tsai, Ming-Jui; Lee, Shyong

    2012-01-01

    Ti-containing amorphous hydrogenated carbon (Ti-C:H) thin films were deposited on stainless steel SS304 substrates by high-power pulsed magnetron sputtering (HPPMS) in an atmosphere of mixed Ar and C 2 H 2 gases using titanium metal as the cathodic material. The multilayer structure of the deposited film had a Ti-TiC-DLC gradient to improve adhesion and reduce residual stress. This study investigates the effects of substrate bias and target-to-substrate distance on the mechanical properties of Ti-C:H films. Film properties, including composition, morphology, microstructure, mechanical, and tribology, were examined by glow discharge spectroscopy (GDS), scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy, and a nanoindenter and a pin-on-disk tribometer. Experiments revealed impressive results.

  4. Fracture analysis of Ag nanobrazing of NiTi to Ti alloy

    Directory of Open Access Journals (Sweden)

    L. Quintino

    2013-09-01

    Full Text Available Dissimilar joining of shape memory alloys to Ti alloys has long been attempted by several research groups due to the foreseen potential industrial applications. However, the very dissimilar thermo-physical properties of both materials place several difficulties. Brazing can be a solution since the base materials are subjected to a less sharp thermal cycle. In the present study brazed overlap joints of 1 mm thick plates of equiatomic NiTi and Ti6Al4V were produced using nano silver based filler materials. Surfaces were analyzed to assess the type of fracture and the capability of achieving bonding and involved mechanisms are discussed.

  5. Fracture analysis of Ag nanobrazing of NiTi to Ti alloy

    Energy Technology Data Exchange (ETDEWEB)

    Quintino, L., E-mail: lquirino@ist.utl.pt [Universidade Tecnica de Lisboa (IST/UTL) (Portugal). Instituto Superior Tecnico. Dept. de Engenharia Mecanica; Liu, L., E-mail: ray.plasma@gmail.com [Tsinghua Univ., Beijing (China). Dept. of Mechanical Engineering; Hu, A.; Zhou, Y., E-mail: anming.hu@uwaterloo.ca, E-mail: nzhou@uwaterloo.ca [University of Waterloo, Ontario (Canada). Dept. of Mechanical Engineering; Miranda, R.M., E-mail: rmiranda@fct.unl.pt [Universidade Nova de Lisboa (UNIDEMI), Caparica (Portugal). Dept. de Engenharia Mecanica e Industrial

    2013-07-15

    Dissimilar joining of shape memory alloys to Ti alloys has long been attempted by several research groups due to the foreseen potential industrial applications. However, the very dissimilar thermo-physical properties of both materials place several difficulties. Brazing can be a solution since the base materials are subjected to a less sharp thermal cycle. In the present study brazed overlap joints of 1 mm thick plates of equiatomic Ni Ti and Ti6Al4V were produced using nano silver based filler materials. Surfaces were analyzed to asses the type of fracture and the capability of achieving bonding and involved mechanisms are discussed. (author)

  6. Influence of C, N and Ti concentration on the intergranular corrosion resistance of AISI 316 Ti stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Pardo, A.; Merino, M.C.; Carboneras, M.; Coy, A.E.; Viejo, F.; Arrabal, R.; Munoz, J.A. [Departamento de Ciencia de Materiales, Facultad de Quimica, Universidad Complutense, 28040, Madrid (Spain)

    2004-07-01

    The influence of Ti, C, and N concentration on the intergranular corrosion resistance of AISI 316 Ti stainless steel has been studied. A kinetic study of the corrosion process has been carried out using gravimetric tests according to ASTM A-262 practices B and C (Streicher and Huey, respectively). The TTS diagrams were drawn as a function of alloying elements concentration (C, N and Ti). Materials characterization under several test conditions was carried out using Scanning Electron Microscopy (SEM) analysing microstructural characteristics and the attack microstructure. The chemical resistance of these steels to intergranular test was function of N, C and Ti concentration. High Ti and N concentration favoured the precipitation of TiN during the material manufacture process. N forms TiN very stable, causing the removal of Ti from the matrix and, indirectly, favouring the Cr{sub 23}C{sub 6} precipitation during the sensitization process and increasing the corrosion rate. In order to inhibit the intergranular corrosion in these materials the N and Ti concentrations must be optimised. (authors)

  7. Influence of C, N and Ti concentration on the intergranular corrosion resistance of AISI 316 Ti stainless steel

    International Nuclear Information System (INIS)

    Pardo, A.; Merino, M.C.; Carboneras, M.; Coy, A.E.; Viejo, F.; Arrabal, R.; Munoz, J.A.

    2004-01-01

    The influence of Ti, C, and N concentration on the intergranular corrosion resistance of AISI 316 Ti stainless steel has been studied. A kinetic study of the corrosion process has been carried out using gravimetric tests according to ASTM A-262 practices B and C (Streicher and Huey, respectively). The TTS diagrams were drawn as a function of alloying elements concentration (C, N and Ti). Materials characterization under several test conditions was carried out using Scanning Electron Microscopy (SEM) analysing microstructural characteristics and the attack microstructure. The chemical resistance of these steels to intergranular test was function of N, C and Ti concentration. High Ti and N concentration favoured the precipitation of TiN during the material manufacture process. N forms TiN very stable, causing the removal of Ti from the matrix and, indirectly, favouring the Cr 23 C 6 precipitation during the sensitization process and increasing the corrosion rate. In order to inhibit the intergranular corrosion in these materials the N and Ti concentrations must be optimised. (authors)

  8. Constitution of the ternary system Cr–Ni–Ti

    International Nuclear Information System (INIS)

    Krendelsberger, Natalja; Weitzer, Franz; Du, Yong; Schuster, Julius C.

    2013-01-01

    Highlights: •Reaction scheme and liquidus surface for Cr-Ni-Ti are given. •In the ternary the C14-type Laves phase coexists with the liquid phase. •Two ternary eutectics are identified. -- Abstract: The nature of solid–liquid phase equilibria in the ternary system Cr–Ni–Ti was investigated using electron microscopy, energy dispersive spectroscopy, X-ray diffraction, and differential thermal analysis. Literature data on solid state phase equilibria are confirmed. The Cr 2 Ti Laves phase modifications coexisting with Ni–Ti phases are clarified to be hexagonal C14-type and cubic C15-type. The C14-type Laves phase γCr 2 Ti is found to coexist with the liquid phase. It forms in the pseudobinary peritectic reaction p max1 from L + β(Cr,Ti) at 1389 °C. On further cooling γCr 2 Ti + NiTi solidify at 1202 °C in the pseudobinary eutectic e max2 . In the Cr-rich part of the system ternary eutectics occur at 1216 °C (E 1 : L = Ni 3 Ti + (Ni) + β(Cr,Ti)) and 1100 °C (E 2 : L = NiTi + Ni 3 Ti + β(Cr,Ti)), respectively. No ternary eutectic is found in the Ti-rich part. Rather the eutectic trough ends in the binary eutectic L = NiTi 2 + β(Ti)

  9. Changing Workplace.

    Science.gov (United States)

    1998

    This document contains four papers from a symposium on the changing workplace and its relationship to human resource development (HRD). In "Globalization, Immigration and Quality of Life Dynamics for Reverse Brain Drains" (Ben-Chieh Liu, Maw Lin Lee, Hau-Lien), the factors responsible for the brain drain from Taiwan to the United States…

  10. Adhesion measurement of highly-ordered TiO2 nanotubes on Ti-6Al-4V alloy

    Directory of Open Access Journals (Sweden)

    Masoud Sarraf

    2017-12-01

    Full Text Available Self-assembled nanotubular arrays on Ti alloys could be used for more effective implantable devices in various medical approaches. In the present work, the adhesion of TiO2 nanotubes (TiO2 NTs on Ti-6Al-4V (Ti64 was investigated by laser spallation and scratch test techniques. At first, electrochemical anodization was performed in an ammonium fluoride solution dissolved in a 90:10 ethane-1,2-diol (ethylene glycol and water solvent mixture. This process was performed at room temperature (23 °C at a steady potential of 60 V for 1 h. Next, the TiO2 nanotubes layer was heat-treated to improve the adhesion of the coating. The formation of selforganized TiO2 nanotubes as well as the microstructural evolution, are strongly dependent on the processing parameters and subsequent annealing. From microscopic analysis, highly oriented arrays of TiO2 nanotubes were grown by thermal treatment for 90 min at 500 °C. Further heat treatment above 500 °C led to the detachment of the nanotubes and the complete destruction of the nanotubes occurred at temperature above 700 °C. Scratch test analysis over a constant scratch length (1000 µm indicated that the failure point was shifted from 247.4 to 557.9 µm while the adhesion strength was increased from ∼862 to ∼1814 mN after annealing at 500 °C. The adhesion measurement determined by laser spallation technique provided an intrinsic adhesion strength of 51.4 MPa for the TiO2 nanotubes on the Ti64 substrate.

  11. Characterising μ-AlTiN coating and assessing its performance during Ti-6Al-4V milling

    Directory of Open Access Journals (Sweden)

    Carlos Mauricio Moreno Téllez

    2013-05-01

    Full Text Available This study investigated the mechanical properties and performance of μ-AlTiN coating deposited by PVD cathodic arc technique for a specific Al0, 67Ti0, 33N composition deposited on a WC-Co and AISI D2 steel substrate. The structure of the coating was analysed using SEM, EDAX, XRD, AFM and TEM. Nano indentation measurements were used for analysing mechanical properties; the coating’s performance was evaluated during the milling of a titanium alloy (Ti6Al4V. The TiN film was initially deposited to improve adhesion between coating and substrate, where columnar grains ranging in size from 200 to 500 nm were observed having NaCl-type struc-ture. μ-AlTiN grain growth was also columnar but had ~50 nm grain size. The μ-AlTiN coated tool life was compared to an uncoated tool to determine the coating’s influence during Ti6Al4V milling. The μ-AlTiN coating improved tool life by 100% compared to that of an uncoated tool due to aluminium oxide and TiC formation on the surface and a decrease in friction coefficient between the chip and the tool.

  12. Hierarchical FeTiO3-TiO2 hollow spheres for efficient simulated sunlight-driven water oxidation.

    Science.gov (United States)

    Han, Taoran; Chen, Yajie; Tian, Guohui; Wang, Jian-Qiang; Ren, Zhiyu; Zhou, Wei; Fu, Honggang

    2015-10-14

    Oxygen generation is the key step for the photocatalytic overall water splitting and considered to be kinetically more challenging than hydrogen generation. Here, an effective water oxidation catalyst of hierarchical FeTiO3-TiO2 hollow spheres are prepared via a two-step sequential solvothermal processes and followed by thermal treatment. The existence of an effective heterointerface and built-in electric field in the surface space charge region in FeTiO3-TiO2 hollow spheres plays a positive role in promoting the separation of photoinduced electron-hole pairs. Surface photovoltage, transient-state photovoltage, fluorescence and electrochemical characterization are used to investigate the transfer process of photoinduced charge carriers. The photogenerated charge carriers in the hierarchical FeTiO3-TiO2 hollow spheres with a proper molar ratio display much higher separation efficiency and longer lifetime than those in the FeTiO3 alone. Moreover, it is suggested that the hierarchical porous hollow structure can contribute to the enhancement of light utilization, surface active sites and material transportation through the framework walls. This specific synergy significantly contributes to the remarkable improvement of the photocatalytic water oxidation activity of the hierarchical FeTiO3-TiO2 hollow spheres under simulated sunlight (AM1.5).

  13. Effect of TiO2 nano fillers on the electrical conductivity of PSAN/TiO2 polymer nanocomposites

    Science.gov (United States)

    Ningaraju, S.; Munirathnamma, L. M.; Kumar, K. V. Aneesh; Ravikumar, H. B.

    2016-05-01

    The microstructural characterization of Polystyrene co-acrylonitrile and Titanium dioxide (PSAN/TiO2) nanocomposites has been performed by Positron Annihilation Lifetime Spectroscopy. The decrease of positron lifetime parameters viz. o-Ps lifetime (τ3) and free volume size (Vf) up to 0.6 wt% of TiO2 is attributed to the filling of free volume holes by TiO2 nanoparticles. The increased free volume size (Vf) after 0.6 wt% of TiO2 indicates the formation of interface due to TiO2 nanoclusters. The variation of electrical conductivity at the lower and higher concentration of TiO2 in (PSAN/TiO2) nanocomposites is attributed to the blocking effect and space charge effect respectively.

  14. Characterization of Al-Ti phases in cycled TiF3-enhanced Na2LiAlH6

    International Nuclear Information System (INIS)

    Nakamura, Y.; Fossdal, A.; Brinks, H.W.; Hauback, B.C.

    2006-01-01

    TiF 3 -enhanced Na 2 LiAlH 6 was investigated after dehydrogenation-hydrogenation cycles by synchrotron X-ray diffraction. There was no sign of Ti after ball-milling with TiF 3 , but two types of Al-Ti phases were observed in the cycled samples. In a sample after measuring five pressure-composition isotherms in the temperature range from 170 to 250 deg. C, a fcc phase with a = 3.987 A was observed. This phase is considered to be Al 3 Ti with the L1 2 structure. Samples after one or four cycles at selected temperatures between 170 and 250 deg. C showed diffraction from another fcc phase with a ∼ 4.03 A. This indicates formation of an Al 1-y Ti y solid-solution phase with y ∼ 0.15 similar to previously reported for cycled NaAlH 4 with Ti additives

  15. Electrorheological effect of Ti-bearing blast furnace slag with different TiC contents at 1500°C

    Science.gov (United States)

    Yue, Hong-rui; Jiang, Tao; Zhang, Qiao-yi; Duan, Pei-ning; Xue, Xiang-xin

    2017-07-01

    The electrorheological properties of CaO-SiO2-Al2O3-MgO-TiO2-TiC slags were investigated to enhance understanding of the effect of TiC addition on the viscosity, yield stress, and fluid pattern of Ti-bearing slags in a direct-current electric field. The viscosities and shear stresses of 4wt% and 8wt% TiC slags were found to increase substantially with increasing electric field intensity, whereas virtually no rheological changes were observed in the 0wt% TiC slag. The Herschel-Bulkley model was applied to demonstrate that the fluid pattern of the 4wt% TiC slag was converted from that of a Newtonian fluid to that of a Bingham fluid in response to the applied electric field; and the static yield stress increased linearly with the square of the electric field intensity.

  16. Measurement of partial coefficients of sputtering of titanium atoms from TiC and TiN coatings

    International Nuclear Information System (INIS)

    Vychegzhanin, G.A.; Gribanov, Yu.A.; Dikij, N.P.; Zhmurin, P.N.; Letuchij, A.N.; Matyash, P.P.; Sidokur, P.I.; Shono, D.A.

    1989-01-01

    Method of laser fluorescent spectroscopy was used to measure partial coefficients of sputtering of titanium atoms from TiC and TiN coatings under irradiation by 1 keV hydrogen ions. Irradiation was conducted in a plant with reflective discharge. Investigation of damaged layer in irradiated samples was conducted. The presence of near-the-surface layer enrichment with titanium atoms was revealed both in TiC and TiN samples. 12 refs.; 4 figs

  17. Absolute isotopic abundances of Ti in meteorites

    International Nuclear Information System (INIS)

    Niederer, F.R.; Papanastassiou, D.A.; Wasserburg, G.J.

    1985-01-01

    The absolute isotope abundance of Ti has been determined in Ca-Al-rich inclusions from the Allende and Leoville meteorites and in samples of whole meteorites. The absolute Ti isotope abundances differ by a significant mass dependent isotope fractionation transformation from the previously reported abundances, which were normalized for fractionation using 46 Ti/ 48 Ti. Therefore, the absolute compositions define distinct nucleosynthetic components from those previously identified or reflect the existence of significant mass dependent isotope fractionation in nature. We provide a general formalism for determining the possible isotope compositions of the exotic Ti from the measured composition, for different values of isotope fractionation in nature and for different mixing ratios of the exotic and normal components. The absolute Ti and Ca isotopic compositions still support the correlation of 50 Ti and 48 Ca effects in the FUN inclusions and imply contributions from neutron-rich equilibrium or quasi-equilibrium nucleosynthesis. The present identification of endemic effects at 46 Ti, for the absolute composition, implies a shortfall of an explosive-oxygen component or reflects significant isotope fractionation. Additional nucleosynthetic components are required by 47 Ti and 49 Ti effects. Components are also defined in which 48 Ti is enhanced. Results are given and discussed. (author)

  18. Minimum ignition energy of nano and micro Ti powder in the presence of inert nano TiO₂ powder.

    Science.gov (United States)

    Chunmiao, Yuan; Amyotte, Paul R; Hossain, Md Nur; Li, Chang

    2014-06-15

    The inerting effect of nano-sized TiO2 powder on ignition sensitivity of nano and micro Ti powders was investigated with a Mike 3 apparatus. "A little is not good enough" is also suitable for micro Ti powders mixed with nano-sized solid inertants. MIE of the mixtures did not significantly increase until the TiO2 percentage exceeded 50%. Nano-sized TiO2 powders were ineffective as an inertant when mixed with nano Ti powders, especially at higher dust loadings. Even with 90% nano TiO2 powder, mixtures still showed high ignition sensitivity because the statistic energy was as low as 2.1 mJ. Layer fires induced by ignited but unburned metal particles may occur for micro Ti powders mixed with nano TiO2 powders following a low level dust explosion. Such layer fires could lead to a violent dust explosion after a second dispersion. Thus, additional attention is needed to prevent metallic layer fires even where electric spark potential is low. In the case of nano Ti powder, no layer fires were observed because of less flammable material involved in the mixtures investigated, and faster flame propagation in nanoparticle clouds. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Microstructure and wear property of the Ti5Si3/TiC reinforced Co-based coatings fabricated by laser cladding on Ti-6Al-4V

    Science.gov (United States)

    Weng, Fei; Yu, Huijun; Liu, Jianli; Chen, Chuanzhong; Dai, Jingjie; Zhao, Zhihuan

    2017-07-01

    Ti5Si3/TiC reinforced Co-based composite coatings were fabricated on Ti-6Al-4V titanium alloy by laser cladding with Co42 and SiC mixture. Microstructure and wear property of the cladding coatings with different content of SiC were investigated. During the cladding process, the original SiC dissolved and reacted with Ti forming Ti5Si3 and TiC. The complex in situ formed phases were found beneficial to the improvement of the coating property. Results indicated that the microhardness of the composite coatings was enhanced to over 3 times the substrate. The wear resistance of the coatings also showed distinct improvement (18.4-57.4 times). More SiC gave rise to better wear resistance within certain limits. However, too much SiC (20 wt%) was not good for the further improvement of the wear property.

  20. Effect of Ni4Ti3 precipitation on martensitic transformation in Ti-Ni

    International Nuclear Information System (INIS)

    Zhou, N.; Shen, C.; Wagner, M.F.-X.; Eggeler, G.; Mills, M.J.; Wang, Y.

    2010-01-01

    Precipitation of Ni 4 Ti 3 plays a critical role in determining the martensitic transformation path and temperature in Ni-Ti shape memory alloys. In this study, the equilibrium shape of a coherent Ni 4 Ti 3 precipitate and the concentration and stress fields around it are determined quantitatively using the phase field method. Most recent experimental data on lattice parameters, elastic constants, precipitate-matrix orientation relationship and thermodynamic database are used as model inputs. The effects of the concentration and stress fields on subsequent martensitic transformations are analyzed through interaction energy between a nucleating martensitic particle and the existing microstructure. Results indicate that R-phase formation prior to B19' phase could be attributed to both direct elastic interaction and stress-induced spatial variation in concentration near Ni 4 Ti 3 precipitates. The preferred nucleation sites for the R-phase are close to the broad side of the lenticular-shaped Ni 4 Ti 3 precipitates, where tension normal to the habit plane is highest, and Ni concentration is lowest.

  1. Functionalized TiO2 nanoparticle containing isocyanate groups

    International Nuclear Information System (INIS)

    Ou, Baoli; Li, Duxin; Liu, Qingquan; Zhou, Zhihua; Liao, Bo

    2012-01-01

    Functionalized TiO 2 nanoparticle containing isocyanate groups can extend the TiO 2 nanoparticle chemistry, and may promote their many potential applications such as in polymer composites and coatings. This paper describes a facile method to prepare functionalized TiO 2 nanoparticle with highly reactive isocyanate groups on its surface, via the reaction between toluene-2, 4-diisocyanate (TDI) and hydroxyl on TiO 2 nanoparticle surface. The main effect factors on the reaction of TiO 2 with TDI were studied by determining the reaction extent of hydroxyl groups on TiO 2 surface. Fourier-transformed infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) confirmed that reactive isocyanate groups were covalently attached to the TiO 2 nanoparticle surface. The dispersion of the TDI-functionalized TiO 2 nanoparticle was studied by transmission electron microscopy (TEM). Owing to the TDI molecules covalently bonded on TiO 2 nanoparticle surface, it was established that the TiO 2 nanoparticle can be uniformly dispersed in toluene, thus indicating that this functionalization method can prevent TiO 2 nanoparticle from agglomerating. -- Highlights: ► TiO 2 nanoparticle was functionalized with toluene-2, 4-diisocyanate. ► Functionalized TiO 2 nanoparticle can be uniformly dispersed in xylene. ► Compatibility of TiO 2 nanoparticle and organic solvent is significantly improved. ► TiO 2 containing isocyanate groups can extend the TiO 2 nanoparticle chemistry.

  2. Synthesis of Ag-loaded SrTiO_3/TiO_2 heterostructure nanotube arrays for enhanced photocatalytic performances

    International Nuclear Information System (INIS)

    Hu, Zijun; Chen, Da; Zhan, Xiaqiang; Wang, Fang; Qin, Laishun; Huang, Yuexiang

    2017-01-01

    In this work, the effect of loading Ag nanoparticles on the photocatalytic activity of SrTiO_3/TiO_2 nanotube arrays (TNTAs) was investigated. TNTAs were partially transformed to SrTiO_3 through a hydrothermal treatment, which could preserve the tubular structure of TNTAs, and then, Ag nanoparticles were well deposited on the surface of SrTiO_3/TNTAs heterostructure by a chemical reduction process. Compared to the TNTAs sample, the Ag-loaded SrTiO_3/TNTAs sample showed significantly enhanced photocatalytic activities for photodegradation of rhodamine B. The enhanced photocatalytic activity of Ag-loaded SrTiO_3/TNTAs could be attributed to the increased optical absorption as well as the efficient charge transfer and separation of photogenerated electron-hole pairs induced by the SrTiO_3/TNTAs heterojunction and the Schottky barrier between metallic Ag and SrTiO_3/TNTAs. On the basis of the trapping experiments, the possible photocatalytic mechanism was also discussed. (orig.)

  3. Improvement of Ti-plasma coating on Ni-Ti shape memory alloy applying to implant materials and its evaluation

    International Nuclear Information System (INIS)

    Okuyama, Masaru; Endo, Jun; Take, Seisho; Itoi, Yasuhiko; Kambe, Satoshi

    2002-01-01

    Utilizing of Ni-Ti shape memory alloy for implant materials has been world-widely studied. it is, however, known that Ni-Ti alloy is easily attacked by chloride ion contained in body liquid. To prevent Ni dissolution, the authors tried to coat the alloy surface with titanium metal by means of plasma-spray coating method. The plasma coating films resulted in rather accelerating pitting corrosion because of their high porosity. Therefore, sealing of the porous films was required. In order to solve this problem and satisfy prolonged lifetime in the body, the authors tried to use the vacuum evaporation technique of titanium metal. Two types of Ti vacuum evaporation procedures were employed. The one was to cover a thin film on Ni-Ti alloy surface prior to massive Ti plasma spray coating. The other was to first coat plasma spray films on Ni-Ti alloy and then to cover them with vacuum evaporation films of Ti. Protective ability against pitting corrosion was examined by electrochemical polarization measurement in physiological solution and the coating films were characterized by microscopic and SEM observation and EPMA analysis. Vacuum evaporation thin films could not protect Ni-Ti alloy from pitting corrosion. In the case of plasma spray coating over the Ti vacuum evaporation thin film, the substrate Ni-Ti alloy could not be better protected. On the contrary, vacuum evaporation of Ti over the porous plasma spray coating layer remarkably improved corrosion protective performance

  4. Rutile TiO2 nanorod arrays directly grown on Ti foil substrates towards lithium-ion micro-batteries

    International Nuclear Information System (INIS)

    Dong Shanmu; Wang Haibo; Gu Lin; Zhou Xinhong; Liu Zhihong; Han Pengxian; Wang Ya; Chen Xiao; Cui Guanglei; Chen Liquan

    2011-01-01

    Nanosized rutile TiO 2 is one of the most promising candidates for anode material in lithium-ion micro-batteries owing to their smaller dimension in ab-plane resulting in an enhanced performance for area capacity. However, few reports have yet emerged up to date of rutile TiO 2 nanorod arrays growing along c-axis for Li-ion battery electrode application. In this study, single-crystalline rutile TiO 2 nanorod arrays growing directly on Ti foil substrates have been fabricated using a template-free method. These nanorods can significantly improve the electrochemical performance of rutile TiO 2 in Li-ion batteries. The capacity increase is about 10 times in comparison with rutile TiO 2 compact layer.

  5. Preparation of thermally stable anatase TiO2 photocatalyst from TiOF2 precursor and its photocatalytic activity

    International Nuclear Information System (INIS)

    Lv Kangle; Yu Jiaguo; Cui Longzhe; Chen Shulin; Li Mei

    2011-01-01

    Graphical abstract: The prepared anatase TiO 2 from TiOF 2 shows very high thermal stability (up to 1000 o C) and the 700 o C-calcined sample showed the highest photocatalytic activity. Display Omitted Research highlights: → TiOF 2 was prepared by a simple microwave assisted hydrothermal rout. → Anatase TiO 2 prepared by calcination of TiOF 2 shows high thermal stability. → F - play an important role in the improvement thermal stability of anatase TiO 2 . → The 700 o C-calcined sample shows the highest photocatalytic activity. - Abstract: Preparation of anatase TiO 2 with high themal stability is of great importance for its environmental application. In this work, TiOF 2 was first synthesized by a simple microwave-assisted hydrothermal route using tetrabutyl titanate and hydrofluoric acid as precursors at 200 o C for 20 min. Then the resulted precipitates were calcined at different temperatures (300-1000 o C) for 2 h. The as-prepared samples were characterized by X-ray diffraction, Raman spectrum, scanning electron microscopy, N 2 adsorption-desorption isotherms and X-ray photoelectron spectroscopy. The photocatalytic activity was evaluated using Brilliant Red X3B, an anionic azo dye, as the target organic molecule under UV light irradiation. The results showed that the prepared TiOF 2 exhibited weak or no photocatalytic activity. The phase transformation of TiOF 2 to anatase TiO 2 occurred at about 300 o C. The prepared anatase TiO 2 from TiOF 2 showed very high thermal stability and the anatase-to-rutile phase transformation temperature was up to 1000 o C. Fluoride ions played an important role in the improvement of thermal stability of anatase TiO 2 by strongly adsorbing on the crystal planes of anatase to stabilize the anatase structure. The 700 o C-calcined sample showed the highest photocatalytic activity due to its relative good crystallization and high specific surface areas.

  6. Preparation and microstructural characterization of TiC and Ti0.6W0.4/TiC0.6 composite thin films obtained by activated reactive evaporation

    International Nuclear Information System (INIS)

    Montes de Oca, J. A.; LePetitcorps, Y.; Manaud, J.-P.; Vargas Garcia, J. R.

    2008-01-01

    Titanium carbide-based coatings were deposited on W substrates at a high coating growth rate by activated reactive evaporation at 500 and 600 deg. C in a L560 Leybold system using propene as reactive atmosphere. The crystal structure, lattice parameter, preferred orientation, and grain size of the coatings were determined by x-ray diffraction technique using Cu Kα. The analysis of the coating morphology was performed by scanning electron microscopy (SEM), and the composition of the films was analyzed by Auger electron spectroscopy and electron-probe microanalysis. Experimental results suggested that temperature was one of the most important parameters in the fabrication of stoichiometric TiC coatings. Thus, TiC coatings were obtained at 600 deg. C, whereas TiC 0.6 nonstoichiometric coatings codeposited with a free Ti phase were obtained at 500 deg. C, giving rise to the formation of a composite thin film. After annealing at 1000 deg. C, the stoichiometric films remained stable, but a crack pattern was formed over the entire coating surface. In addition, Ti 0.6 W 0.4 /TiC 0.6 composite thin coatings were obtained for the films synthesized at 500 deg. C. The formation of a Ti 0.6 W 0.4 ductile phase in the presence of a TiC 0.6 phase was responsible to avoid the coating cracking

  7. Synthesis of a TiBw/Ti6Al4V composite by powder compact extrusion using a blended powder mixture

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Huiyang, E-mail: hl209@waikato.ac.nz [Waikato Center for Advanced Materials, School of Engineering, University of Waikato, Hamilton (New Zealand); Zhang, Deliang, E-mail: zhangdeliang@sjtu.edu.cn [State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai (China); Gabbitas, Brian, E-mail: briang@waikato.ac.nz [Waikato Center for Advanced Materials, School of Engineering, University of Waikato, Hamilton (New Zealand); Yang, Fei, E-mail: fyang@waikato.ac.nz [Waikato Center for Advanced Materials, School of Engineering, University of Waikato, Hamilton (New Zealand); Matthews, Steven, E-mail: S.Matthews@massey.ac.nz [School of Engineering and Advanced Technology, Massey University, Auckland (New Zealand)

    2014-09-01

    Highlights: • TiB/Ti6Al4V composites were prepared from extruded BE powders. • Different starting powders affected the morphologies of TiB whiskers formed in-situ. • A TiB/Ti6Al4V composite with TiB whiskers had good strength and ductility. • The strength and ductility achieved were superior to those obtained by other methods. - Abstract: A Ti–6 wt%Al–4 wt%V alloy (Ti6Al4V) matrix composite, reinforced by in situ synthesized TiB whiskers (TiBw) has been successfully fabricated by powder compact extrusion using a blended powder mixture. The microstructural characterization of the various extruded samples showed that the different starting powders, pre-alloyed powder plus boron powder or titanium plus Al–40V master alloy powder plus boron powder, had a significant effect on the morphology of the in situ synthesized TiB whiskers. It is also evident that the TiB whiskers affect the microstructural evolution of the Ti6Al4V matrix. The tensile test results indicated that the composite with a dispersion of fine TiB whiskers with high aspect ratios exhibited a high ultimate tensile stress (UTS) and yield stress (YS) of 1436 MPa and 1361 MPa, respectively, a reasonably good tensile ductility reflected by an elongation to fracture of 5.6% was also achieved. This is a significant improvement compared with as-extruded monolithic Ti6Al4V alloy produced in this study.

  8. Synthesis of a TiBw/Ti6Al4V composite by powder compact extrusion using a blended powder mixture

    International Nuclear Information System (INIS)

    Lu, Huiyang; Zhang, Deliang; Gabbitas, Brian; Yang, Fei; Matthews, Steven

    2014-01-01

    Highlights: • TiB/Ti6Al4V composites were prepared from extruded BE powders. • Different starting powders affected the morphologies of TiB whiskers formed in-situ. • A TiB/Ti6Al4V composite with TiB whiskers had good strength and ductility. • The strength and ductility achieved were superior to those obtained by other methods. - Abstract: A Ti–6 wt%Al–4 wt%V alloy (Ti6Al4V) matrix composite, reinforced by in situ synthesized TiB whiskers (TiBw) has been successfully fabricated by powder compact extrusion using a blended powder mixture. The microstructural characterization of the various extruded samples showed that the different starting powders, pre-alloyed powder plus boron powder or titanium plus Al–40V master alloy powder plus boron powder, had a significant effect on the morphology of the in situ synthesized TiB whiskers. It is also evident that the TiB whiskers affect the microstructural evolution of the Ti6Al4V matrix. The tensile test results indicated that the composite with a dispersion of fine TiB whiskers with high aspect ratios exhibited a high ultimate tensile stress (UTS) and yield stress (YS) of 1436 MPa and 1361 MPa, respectively, a reasonably good tensile ductility reflected by an elongation to fracture of 5.6% was also achieved. This is a significant improvement compared with as-extruded monolithic Ti6Al4V alloy produced in this study

  9. Investigation on Tribological Properties of the Pre-oxidized Ti2AlN/TiAl Composite

    Science.gov (United States)

    Wang, Daqun; Sun, Dongli; Han, Xiuli; Wang, Qing; Wang, Guangwei

    2018-03-01

    Different oxidation layers on the Ti2AlN/TiAl substrate which was fabricated by in situ synthesis were prepared through thermal oxidation process. The microstructure, phase identification and elements distribution of the oxidation layers were analyzed. The tribological performance of pre-oxidized composites against Si3N4 ball at 25 and 600 °C, as well as the effect of pre-oxidation layers on tribological performance was systematically investigated. The results show that, compared to Ti2AlN/TiAl, the pre-oxidized composites present more excellent tribological properties, especially the wear resistance at 600 °C. It is a significant finding that, different from severe abrasive wear and plastic deformation of Ti2AlN/TiAl, the tribo-films formed by the pre-oxidation layers on the worn surface of pre-oxidized composites weaken abrasive wear and suppress the development of plastic deformation to protect the underlying composite substrate from wear. Moreover, the stable cooperation on the interface between tribo-films and Si3N4 ball results in the relatively steady friction coefficient.

  10. Equation of State Model Quality Study for Ti and Ti64.

    Energy Technology Data Exchange (ETDEWEB)

    Wills, Ann Elisabet [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Sanchez, Jason James [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-02-01

    Titanium and the titanium alloy Ti64 (6% aluminum, 4% vanadium and the balance ti- tanium) are materials used in many technologically important applications. To be able to computationally investigate and design these applications, accurate Equations of State (EOS) are needed and in many cases also additional constitutive relations. This report describes what data is available for constructing EOS for these two materials, and also describes some references giving data for stress-strain constitutive models. We also give some suggestions for projects to achieve improved EOS and constitutive models. In an appendix, we present a study of the 'cloud formation' issue observed in the ALEGRA code. This issue was one of the motivating factors for this literature search of available data for constructing improved EOS for Ti and Ti64. However, the study shows that the cloud formation issue is only marginally connected to the quality of the EOS, and, in fact, is a physical behavior of the system in question. We give some suggestions for settings in, and improvements of, the ALEGRA code to address this computational di culty.

  11. Properties of TiO2 prepared by acid treatment of BaTiO3

    International Nuclear Information System (INIS)

    Okada, Kiyoshi; Yanagisawa, Tomoki; Kameshima, Yoshikazu; Nakajima, Akira

    2007-01-01

    TiO 3 powders were prepared by acid treatment of BaTiO 3 and their properties were investigated. The BaTiO 3 powder was subjected to HNO 3 in concentrations ranging from 10 -3 to 8 M at 90 deg. C for 0.5-6 h. Dissolution of BaTiO 3 and precipitation of TiO 2 occurred at acid concentrations of 2-5 M. BaTiO 3 dissolves completely to form a clear solution at reaction times of 0.5-1 h, but a rutile precipitate is formed after 2 h of acid treatment. By contrast, anatase is precipitated by adjusting the pH of the clear solution to 2-3 using NaOH or NH 4 OH solution. The rutile crystals were small and rod-shaped, consisting of many small coherent domains connected by grain boundaries with small inclination angles and edge dislocations, giving them a high specific surface area (S BET ). With increasing HNO 3 concentration, the S BET value increased from 100 to 170 m 2 /g while the crystallite size decreased from 25 to 11 nm. The anatase crystals obtained here were very small equi-axial particles with a smaller crystallite size than the rutile and S BET values of about 270 m 2 /g (higher than the rutile samples). The photocatalytic activity of these TiO 2 was determined from the decomposition rate of Methylene Blue under ultraviolet irradiation. Higher decomposition rates were obtained with larger crystallite sizes resulting from heat treatment. The maximum decomposition rates were obtained in samples heated at 500-600 deg. C. The photocatalytic activity of the TiO 2 was found to depend more strongly on the sample crystallite size than on S BET

  12. Biological Properties of Ti-Nb-Zr-O Nanostructures Grown on Ti35Nb5Zr Alloy

    Directory of Open Access Journals (Sweden)

    Zhaohui Li

    2012-01-01

    Full Text Available Surface modification of low modulus implant alloys with oxide nanostructures is one of the important ways to achieve favorable biological behaviors. In the present work, amorphous Ti-Nb-Zr-O nanostructures were grown on a peak-aged Ti35Nb5Zr alloy through anodization. Biological properties of the Ti-Nb-Zr-O nanostructures were investigated through in vitro bioactivity testings, stem cell interactions, and drug release experiments. The Ti-Nb-Zr-O nanostructures demonstrated a good capability of inducing apatite formation after immersion in simulated body fluids (SBFs. Drug delivery experiment based on gentamicin and the Ti-Nb-Zr-O nanostructures indicated that a high drug loading content could result in a prolonged release process and a higher quantity of drug residues in the oxide nanostructures after drug release. Quick stem cell adhesion and spreading, as well as fast formation of extracellular matrix materials on the surfaces of the Ti-Nb-Zr-O nanostructures, were found. These findings make it possible to further explore the biomedical applications of the Ti-Nb-Zr-O nanostructure modified alloys especially clinical operation of orthopaedics by utilizing the nanostructures-based drug-release system.

  13. Sadhana | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Home; Journals; Sadhana. M-H Shih. Articles written in Sadhana. Volume 34 Issue 3 June 2009 pp 421-437. A model for signal processing and predictive control of semi-active structural control system · M-H Shih W-P Sung Ching-Jong Wang · More Details Abstract Fulltext PDF. The theory for structural control has been ...

  14. Characterization of Al/Ni multilayers and their application in diffusion bonding of TiAl to TiC cermet

    International Nuclear Information System (INIS)

    Cao, J.; Song, X.G.; Wu, L.Z.; Qi, J.L.; Feng, J.C.

    2012-01-01

    The Al/Ni multilayers were characterized and diffusion bonding of TiAl intermetallics to TiC cermets was carried out using the multilayers. The microstructure of Al/Ni multilayers and TiAl/TiC cermet joint was investigated. The layered structures consisting of a Ni 3 (AlTi) layer, a Ni 2 AlTi layer, a (Ni,Al,Ti) layer and a Ni diffusion layer were observed from the interlayer to the TiAl substrate. Only one AlNi 3 layer formed at the multilayer/TiC cermet interface. The reaction behaviour of Al/Ni multilayers was characterized by means of differential scanning calorimeter (DSC) and X-ray diffraction. The initial exothermic peak of the DSC curve was formed due to the formation of Al 3 Ni and Al 3 Ni 2 phases. The reaction sequence of the Al/Ni multilayers was Al 3 Ni → Al 3 Ni 2 → AlNi → AlNi 3 and the final products were AlNi and AlNi 3 phases. The shear strength of the joint was tested and the experimental results suggested that the application of Al/Ni multilayers improved the joining quality. - Highlights: ► Diffusion bonding of TiAl to TiC cermet was realized using Al/Ni multilayer. ► The reaction sequence of the Al/Ni multilayers was Al 3 Ni → Al 3 Ni 2 → AlNi → AlNi 3 . ► The interfacial microstructure of the joint was clarified. ► The application of Al/Ni multilayers improved the joining quality.

  15. Journal of Genetics | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Genetic variants of retinol-binding protein 4 in adolescents are associated with liver function and inflammatory markers but not with obesity and insulin resistance. Chin-Jung Lin Nain-Feng Chu Yi-Jen Hung Dee Pei Chien-Hsing Lee Fone-Ching Hsiao Chieh-Hua Lu Chang-Hsun Hsieh. Research Note Volume 94 Issue 3 ...

  16. Formation of hydroxyl radicals and kinetic study of 2-chlorophenol photocatalytic oxidation using C-doped TiO2, N-doped TiO2, and C,N Co-doped TiO2 under visible light.

    Science.gov (United States)

    Ananpattarachai, Jirapat; Seraphin, Supapan; Kajitvichyanukul, Puangrat

    2016-02-01

    This work reports on synthesis, characterization, adsorption ability, formation rate of hydroxyl radicals (OH(•)), photocatalytic oxidation kinetics, and mineralization ability of C-doped titanium dioxide (TiO2), N-doped TiO2, and C,N co-doped TiO2 prepared by the sol-gel method. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and UV-visible spectroscopy were used to analyze the titania. The rate of formation of OH(•) for each type of titania was determined, and the OH-index was calculated. The kinetics of as-synthesized TiO2 catalysts in photocatalytic oxidation of 2-chlorophenol (2-CP) under visible light irradiation were evaluated. Results revealed that nitrogen was incorporated into the lattice of titania with the structure of O-Ti-N linkages in N-doped TiO2 and C,N co-doped TiO2. Carbon was joined to the Ti-O-C bond in the C-doped TiO2 and C,N co-doped TiO2. The 2-CP adsorption ability of C,N co-doped TiO2 and C-doped TiO2 originated from a layer composed of a complex carbonaceous mixture at the surface of TiO2. C,N co-doped TiO2 had highest formation rate of OH(•) and photocatalytic activity due to a synergistic effect of carbon and nitrogen co-doping. The order of photocatalytic activity per unit surface area was the same as that of the formation rate of OH(•) unit surface area in the following order: C,N co-doped TiO2 > C-doped TiO2 > N-doped TiO2 > undoped TiO2.

  17. A Comparative Study on Corrosion Behavior of Ti-35Nb-5Ta-7Zr Ti-6Al-4V and CP-Ti in 0.9 wt% NaCl

    Energy Technology Data Exchange (ETDEWEB)

    Saji, Viswanathan S.; Jeong, Yong Hoon; Choe, Han Cheol [Andong National University, Andong (Korea, Republic of)

    2009-08-15

    Recently, quaternary titanium alloys of the system Ti-Nb-Ta-Zr received considerable research considerable research interest as potential implant materials because of their excellent mechanical properties and biocompatibility. However, only few reported works were available on the corrosion behavior of such alloys. Hence, in the present work, electrochemical corrosion of Ti-35Nb-5Ta-7Zr alloy, which has been fabricated by are melting and heat treatment, was studied in 0.9 wt% NaCl at 37{+-}1 .deg. C, along with biomedical grade Ti-6Al-4V and CP-Ti. The phase and microstructure of the alloys were investigated employing XRD and SEM. The results of electrochemical studies indicated that the corrosion resistance of the quaternary alloy was inferior to that of Ti-6Al-4V and CP Ti.

  18. Effect of TiO2 on the Gas Sensing Features of TiO2/PANi Nanocomposites

    Directory of Open Access Journals (Sweden)

    Duong Ngoc Huyen

    2011-02-01

    Full Text Available A nanocomposite of titanium dioxide (TiO2 and polyaniline (PANi was synthesized by in-situ chemical polymerization using aniline (ANi monomer and TiCl4 as precursors. SEM pictures show that the nanocomposite was created in the form of long PANi chains decorated with TiO2 nanoparticles. FTIR, Raman and UV-Vis spectra reveal that the PANi component undergoes an electronic structure modification as a result of the TiO2 and PANi interaction. The electrical resistor of the nanocomposite is highly sensitive to oxygen and NH3 gas, accounting for the physical adsorption of these gases. A nanocomposite with around 55% TiO2 shows an oxygen sensitivity of 600–700%, 20–25 times higher than that of neat PANi. The n-p contacts between TiO2 nanoparticles and PANi matrix give rise to variety of shallow donors and acceptor levels in the PANi band gap which enhance the physical adsorption of gas molecules.

  19. High-temperature fracture and fatigue resistance of a ductile β-TiNb reinforced γ-TiAl intermetallic composite

    International Nuclear Information System (INIS)

    Rao, K.T.V.; Ritchie, R.O.

    1998-01-01

    The high-temperature fatigue-crack propagation and fracture resistance of a model γ-TiAl intermetallic composite reinforced with 20 vol. % ductile β-TiNb particles is examined at elevated temperatures of 650 and 800 C and compared with behavior at room temperature. TiNb reinforcements are found to enhance the fracture toughness of γ-TiAl, even at high temperatures, from about 123 to ∼40 MPa m 1/2 , although their effectiveness is lower compared to room temperature due to the reduction in strength of TiNb particles. Under monotonic loading, crack-growth response in the composite is characterized by resistance-curve behavior arising from crack trapping, renucleation and resultant crack bridging effects attributable to the presence of TiNb particles. In addition, crack-tip blunting associated with plasticity increases the crack-initiation (matrix) toughness of the composite, particularly at 800 C, above the ductile-to-brittle transition temperature (DBTT) for γ-TiAl. High-temperature fatigue-crack growth resistance, however, is marginally degraded by the addition of TiNb particles in the C-R (edge) orientation, similar to observations made at room temperature; premature fatigue failure of TiNb ligaments in the crack wake diminishes the role of bridging under cyclic loading. Both fatigue and fracture resistance of the composite are slightly lower at 650 C (just below the DBTT for TiAl) compared to the behavior at ambient and 800 C. Overall, the beneficial effect of adding ductile TiNb reinforcements to enhance the room-temperature fracture and fatigue resistance of γ-TiAl alloys is retained up to 800 C, in air environments. There is concern, however, regarding the long-term environmental stability of these composite microstructures in unprotected atmospheres

  20. Structural and electrical properties of Barium Titanate (BaTiO3 and Neodymium doped BaTiO3 (Ba0.995Nd0.005TiO3

    Directory of Open Access Journals (Sweden)

    Tuan Sulong Tuan Amirah

    2017-01-01

    Full Text Available Barium titanate (BaTiO3 and Neodymium (Nd doped BaTiO3 with composition Ba0.995Nd0.005TiO3 were prepared using conventional solid state reaction method to study the dielectric properties of materials. Pure phase samples were found at final heating temperature of 1400°C for overnight. X-ray diffraction analysis reveals the changes in the lattice parameter and unit cell volume of the pure perovskite tetragonal structure with space group (P4mm. Electrical analysis is carried out to investigate the dielectric properties, conductivity behaviour and dielectric loss of BaTiO3 and Ba0.995Nd0.005TiO3. Ba0.995Nd0.005TiO3 have a broaden dielectric peaks with high permittivity of 8000 and reasonably low loss tan δ which is about 0.004 (1 kHz.

  1. Effect of chemical treatment on surface characteristics of sputter deposited Ti-rich NiTi shape memory alloy thin-films

    International Nuclear Information System (INIS)

    Sharma, S.K.; Mohan, S.

    2014-01-01

    Graphical abstract: FTIR spectra recorded for sputter deposited (a) untreated and (b) chemically treated NiTi SMA thin-films. - Highlights: • The effect of chemical treatment on surface properties of NiTi films demonstrated. • Chemically treated films offer strong ability to form protective TiO 2 layer. • TiO 2 layer formation offer great application prospects in biomedical fields. - Abstract: NiTi thin-films were deposited by DC magnetron sputtering from single alloy target (Ni/Ti:45/55 at.%). The rate of deposition and thickness of sputter deposited films were maintained to ∼35 nm min −1 and 4 μm respectively. A set of sputter deposited NiTi films were selected for specific chemical treatment with the solution comprising of de-ionized water, HF and HNO 3 respectively. The influence of chemical treatment on surface characteristics of NiTi films before and after chemical treatment was investigated for their structure, micro-structure and composition using different analytical techniques. Prior to chemical treatment, the composition of NiTi films using energy dispersive X-ray dispersive spectroscopy (EDS), were found to be 51.8 atomic percent of Ti and 48.2 atomic percent of Ni. The structure and morphology of these films were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). XRD investigations, demonstrated the presence of dominant Austenite (1 1 0) phase along with Martensite phase, for untreated NiTi films whereas some additional diffraction peaks viz. (1 0 0), (1 0 1), and (2 0 0) corresponding to Rutile and Anatase phase of Titanium dioxide (TiO 2 ) along with parent Austenite (1 1 0) phase were observed for chemically treated NiTi films. FTIR studies, it can be concluded that chemically treated films have higher tendency to form metal oxide/hydroxide than the untreated NiTi films. XPS investigations, demonstrated the presence of Ni-free surface and formation of a protective metal oxide (TiO 2 ) layer on the surface of

  2. Characterization and hardness of TiCu–Ti2Cu3 intermetallic material fabricated by mechanical alloying and subsequent annealing

    International Nuclear Information System (INIS)

    Akbarpour, Mohammad Reza; Hesari, Feridoun Alikhani

    2016-01-01

    In this research, the microstructural and phase evolutions during mechanical alloying (MA) and subsequent heat treatment of Cu–Ti powder mixture are investigated through x-ray diffraction, scanning electron microscopy, transmission electron microscopy and micro-hardness measurements. The obtained experimental results demonstrated that after an optimum MA time of 30 h, TiCu intermetallic compound was achieved with a mean grain size of ≈8 nm and a high micro-hardness value of ≈634 Hv. Annealing the milled powder at different temperatures resulted in formation of major TiCu and Ti 2 Cu 3 , and minor Ti 2 Cu and Cu 4 Ti nanocrystalline phases, release of internal strain, and coarsening of grains. The amount of TiCu phase and the grain size increased with increase of the annealing temperature. Micro-hardness value of ≈765 Hv was recorded when the milled TiCu powder was annealed at 850 °C. This superior high micro-hardness value can be attributed to formation of higher amount of TiCu phase. (paper)

  3. Catalytic formal [2+2+1] synthesis of pyrroles from alkynes and diazenes via Ti(II)/Ti(IV) redox catalysis.

    Science.gov (United States)

    Gilbert, Zachary W; Hue, Ryan J; Tonks, Ian A

    2016-01-01

    Pyrroles are structurally important heterocycles. However, the synthesis of polysubstituted pyrroles is often challenging. Here, we report a multicomponent, Ti-catalysed formal [2+2+1] reaction of alkynes and diazenes for the oxidative synthesis of penta- and trisubstituted pyrroles: a nitrenoid analogue to classical Pauson-Khand-type syntheses of cyclopentenones. Given the scarcity of early transition-metal redox catalysis, preliminary mechanistic studies are presented. Initial stoichiometric and kinetic studies indicate that the mechanism of this reaction proceeds through a formally Ti(II)/Ti(IV) redox catalytic cycle, in which an azatitanacyclobutene intermediate, resulting from [2+2] alkyne + Ti imido coupling, undergoes a second alkyne insertion followed by reductive elimination to yield pyrrole and a Ti(II) species. The key component for catalytic turnover is the reoxidation of the Ti(II) species to a Ti(IV) imido via the disproportionation of an η(2)-diazene-Ti(II) complex.

  4. Fabrication of TiO_2 nanorod assembly grafted rGO (rGO@TiO_2-NR) hybridized flake-like photocatalyst

    International Nuclear Information System (INIS)

    Lv, Kangle; Fang, Shun; Si, Lingling; Xia, Yang; Ho, Wingkei; Li, Mei

    2017-01-01

    Highlights: • TiO_2 nanorod assembly grafted with GO hybrid was successfully fabricated. • TiO_2 nanorods can reduce the aggregation of TiO_2 nanoparticles on graphene. • This unique structure facilitates the injection of electron from TiO_2 to graphene. - Abstract: To efficiently separate the photo-generated electron–hole pairs of TiO_2 hybrid, anatase TiO_2 nanorod assembly grafted reduced graphene oxides (rGO@TiO_2-NR) hybrid was successfully fabricated using potassium titanium oxalate (PTO) and graphene oxides (GO) as starting materials and diethylene glycol (DEG) as reductant. The effect of GO content on the structure and photocatalytic activity of rGO@TiO_2-NR composite was systematically studied. Results show that, in the absence of GO, only TiO_2 microsphere assembly is obtained from TiO_2 nanorods. The presence of GO results in the formation of a flake-like TiO_2-nanorod-assembled grafted rGO hybrid. The photocatalytic activity of rGO@TiO_2-NR composite increases first and then decreases with increase in the amount of GO from 0 wt.% to 10 wt.%. The hybridized S4 sample prepared with 4 wt.% GO possesses the highest photocatalytic activity with a constant rate of 0.039 min"−"1 in the photocataytic degradation of Brilliant X-3B dye (X3B); this sample was enhanced more than three times when compared with pure TiO_2 sample (0.012 min"−"1). The enhanced photocatalytic activity of the rGO@TiO_2-NR hybrid was attributed to the strong interaction between TiO_2 nanorods and rGO. The unique hierarchical structure of 1D nanorod assembly TiO_2–rGO flakes facilitates the injection and transfer of photo-generated electrons from TiO_2 to graphene, thus retarding the recombination of electron–hole pairs and enhancing the photocatalytic activity. The enlarged BET surface areas, not only increasing the number of active sites, but also facilitating the adsorption of the dye, and improved light-harvesting ability also contribute to the enhanced photoreactivity

  5. C, N co-doped TiO_2/TiC_0_._7N_0_._3 composite coatings prepared from TiC_0_._7N_0_._3 powder using ball milling followed by oxidation

    International Nuclear Information System (INIS)

    Hao, Liang; Wang, Zhenwei; Zheng, Yaoqing; Li, Qianqian; Guan, Sujun; Zhao, Qian; Cheng, Lijun; Lu, Yun; Liu, Jizi

    2017-01-01

    Highlights: • TiO_2/TiC_0_._7N_0_._3 coatings were prepared by ball milling followed by oxidation. • In situ co-doping of C and N with simultaneous TiO_2 formation was observed. • Improved photocatalytic activity under UV/visible light was noticed. • Synergism in co-doping and heterojunction formation promoted carrier separation. - Abstract: Ball milling followed by heat oxidation was used to prepared C, N co-doped TiO_2 coatings on the surfaces of Al_2O_3 balls from TiC_0_._7N_0_._3 powder. The as-prepared coatings were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and ultraviolet-visible spectrophotometer (UV–vis). The results show that continuous TiC_0_._7N_0_._3 coatings were formed after ball milling. C, N co-doped TiO_2/TiC_0_._7N_0_._3 composite coatings were prepared after the direct oxidization of TiC_0_._7N_0_._3 coatings in the atmosphere. However, TiO_2 was hardly formed in the surface layer of TiC_0_._7N_0_._3 coatings within a depth less than 10 nm during the heat oxidation of TiC_0_._7N_0_._3 coatings in carbon powder. Meanwhile, the photocatalytic activity evaluation of these coatings was conducted under the irradiation of UV and visible light. All the coatings showed photocatalytic activity in the degradation of MB no matter under the irradiation of UV or visible light. The C, N co-doped TiO_2/TiC_0_._7N_0_._3 composite coatings showed the most excellent performance. The enhancement under visible light irradiation should attribute to the co-doping of carbon and nitrogen, which enhances the absorption of visible light. The improvement of photocatalytic activity under UV irradiation should attribute to the synergistic effect of C, N co-doping, the formation of rutile-anatase mixed phases and the TiO_2/TiC_0_._7N_0_._3 composite microstructure.

  6. Identification of ultra-fine Ti-rich precipitates in V-Cr-Ti alloys irradiated below 300 deg. C by using positron CDB technique

    International Nuclear Information System (INIS)

    Fukumoto, Ken-ichi; Matsui, Hideki; Ohkubo, Hideaki; Tang, Zheng; Nagai, Yasuyoshi; Hasegawa, Masayuki

    2008-01-01

    Irradiation-induced Ti-rich precipitates in V-Ti and V-4Cr-4Ti alloys are studied by TEM and positron annihilation methods (positron lifetime, and coincidence Doppler broadening (CDB)). The characteristics of small defect clusters formed in V alloys containing Ti at irradiation temperatures below 300 deg. C have not been identified by TEM techniques. Strong interaction between vacancy and Ti solute atoms for irradiated V alloys containing Ti at irradiation temperatures from 220 to 350 deg. C are observed by positron lifetime measurement. The vacancy-multi Ti solute complexes in V-alloys containing Ti are definitely identified by using CDB measurement. It is suggested that ultra-fine Ti-rich precipitates or Ti segregation at periphery of dislocation loops are formed in V alloys containing Ti at irradiation temperatures below 300 deg. C

  7. The characteristics of TiC and oxidation resistance and mechanical properties of TiC coated graphite under corrosive environment

    International Nuclear Information System (INIS)

    Yoda, Shinichi; Oku, Tatsuo; Ioka, Ikuo; Umekawa, Shokichi.

    1982-07-01

    Core region of the Very High Temperature Gas Cooled Reactor (VHTR) consists mainly of polycrystalline graphite whose mechanical properties degradated by corrosion resulting from such impurities as O 2 , H 2 O, and CO 2 in coolant He gas. Mechanical properties and oxidation resistance of TiC coated graphite under corrosive condition were examined in order to evaluate the effects of TiC coating on preventing the graphite from its degradation in service condition of the VHTR. Characteristics of TiC coating was also examined using EPMA. Holding the specimen at 1373 K for 6 hr produced strong interface between TiC coating and the graphite, however, microcracks on TiC coating was observed, the origin of which is ascribed to mismatch in thermal expansion between TiC coating and the graphite. Oxidation rate of TiC coated graphite was one-thirds of that of uncoated graphite, which demonstrated that TiC coating on the graphite improved the oxidation resistance of the graphite. However, debonding of TiC coating layer at the interface was observed after heating for 3 to 4 hr in the oxidation condition. Changes in Young's modulus of TiC coated graphite were a half of that of uncoated graphite. Flexural strength of TiC coated graphite remained at the original value up to about 4 hr oxidation, therafter it decreased abruptly as was the trend of uncoated graphite. It is concluded that TiC coating on graphite materials is very effective in improving oxidation resistance and suppressing degradation of mechanical properties of the graphite. (author)

  8. Amorphous surface layers in Ti-implanted Fe

    International Nuclear Information System (INIS)

    Knapp, J.A.; Follstaedt, D.M.; Picraux, S.T.

    1979-01-01

    Implanting Ti into high-purity Fe results in an amorphous surface layer which is composed of not only Fe and Ti, but also C. Implantations were carried out at room temperature over the energy range 90 to 190 keV and fluence range 1 to 2 x 10 16 at/cm 2 . The Ti-implanted Fe system has been characterized using transmission electron microscopy (TEM), ion backscattering and channeling analysis, and (d,p) nuclear reaction analysis. The amorphous layer was observed to form at the surface and grow inward with increasing Ti fluence. For an implant of 1 x 10 17 Ti/cm 2 at 180 keV the layer thickness was 150 A, while the measured range of the implanted Ti was approx. 550 A. This difference is due to the incorporation of C into the amorphous alloy by C being deposited on the surface during implantation and subsequently diffusing into the solid. Our results indicate that C is an essential constituent of the amorphous phase for Ti concentrations less than or equal to 10 at. %. For the 1 x 10 17 Ti/cm 2 implant, the concentration of C in the amorphous phase was approx. 25 at. %, while that of Ti was only approx. 3 at. %. A higher fluence implant of 2 x 10 17 Ti/cm 2 produced an amorphous layer with a lower C concentration of approx. 10 at. % and a Ti concentration of approx. 20 at. %

  9. Characterization of optical and microstructural properties of semitransparent TiO{sub 2}/Ti/glass interference decorative coatings

    Energy Technology Data Exchange (ETDEWEB)

    Skowronski, L., E-mail: lukasz.skowronski@utp.edu.pl; Wachowiak, A.A.; Grabowski, A.

    2016-12-01

    Highlights: • The interference color TiO{sub 2}/Ti/glass systems were produced using the GIMS. • The thicknesses of Ti films (12–73 nm) is associated with the transmittance of samples. • The thicknesses of TiO{sub 2} film determine the color of a sample from gold (11 nm) to blue (47 nm). • The samples with thicker titanium film exhibit more saturated colors. • The elaborated method can be used to produce architectural glazing. - Abstract: This paper presents a study of the optical properties and the microstructure of semitransparent interference TiO{sub 2}/Ti/glass systems obtained by gas injection magnetron sputtering (GIMS). The samples are examined by means of spectroscopic ellipsometry, spectrophotometry and atomic force microscopy. The investigation is complemented by colorimetric measurements. Optical constants of titanium and titanium dioxide layers are determined and carefully studied. An influence of the deposition time on the thickness of metallic and dielectric films has been found. The thickness of Ti films ranges from 12 nm to 73 nm, while that of TiO{sub 2} films varies from 11 nm to 43 nm. This thickness directly determines the color of a sample from gold to blue, respectively.

  10. Topotactic oxidation of TiGaPO-1, a pyridine-templated titanium gallophosphate with a new octahedral-tetrahedral 3-D framework structure containing Ti(III)/Ti(IV).

    Science.gov (United States)

    Chippindale, Ann M; Grimshaw, Mark R; Powell, Anthony V; Cowley, Andrew R

    2005-06-13

    The first 3-D open-framework TiGaPO complex, constructed from Ti(III)O(6), Ti(IV)O(6), GaO(4), and PO(4) polyhedra, contains pyridinium cations in a 1-D pore network and can be oxidized in air at 543 K with retention of the original framework structure.

  11. Molecular dynamics study of the interactions of incident N or Ti atoms with the TiN(001) surface

    International Nuclear Information System (INIS)

    Xu, Zhenhai; Zeng, Quanren; Yuan, Lin; Qin, Yi; Chen, Mingjun; Shan, Debin

    2016-01-01

    Graphical abstract: - Highlights: • Interactions of incident N or Ti atoms with TiN(001) surface are studied by CMD. • The impact position of incident N on the surface determines the interaction modes. • Adsorption could occur due to the atomic exchange process. • Resputtering and reflection may simultaneously occur. • The initial sticking coefficient of N on TiN(001) is much smaller than that of Ti. - Abstract: The interaction processes between incident N or Ti atoms and the TiN(001) surface are simulated by classical molecular dynamics based on the second nearest-neighbor modified embedded-atom method potentials. The simulations are carried out for substrate temperatures between 300 and 700 K and kinetic energies of the incident atoms within the range of 0.5–10 eV. When N atoms impact against the surface, adsorption, resputtering and reflection of particles are observed; several unique atomic mechanisms are identified to account for these interactions, in which the adsorption could occur due to the atomic exchange process while the resputtering and reflection may simultaneously occur. The impact position of incident N atoms on the surface plays an important role in determining the interaction modes. Their occurrence probabilities are dependent on the kinetic energy of incident N atoms but independent on the substrate temperature. When Ti atoms are the incident particles, adsorption is the predominant interaction mode between particles and the surface. This results in the much smaller initial sticking coefficient of N atoms on the TiN(001) surface compared with that of Ti atoms. Stoichiometric TiN is promoted by N/Ti flux ratios larger than one.

  12. Micro-Arc oxidation of Ti in a solution of sulfuric acid and Ti+3 salt

    International Nuclear Information System (INIS)

    Ragalevicius, Rimas; Stalnionis, Giedrius; Niaura, Gediminas; Jagminas, Arunas

    2008-01-01

    A comparative study was performed on the behavior of titanium electrode in a sulfuric acid solution with and without Ti +3 during micro-arc oxidation under the constant current density control regime. The composition and microstructure of the obtained micro-arc films were analyzed using scanning electron microscopy, glancing-angle X-ray diffractometry, Raman and energy-dispersive X-ray spectroscopies. We have shown that addition of a Ti +3 salt extends the region of current densities (j a ) can be used for micro-arc oxidation of Ti and results in an obvious change of sparking behavior from extensive, large and long-played sparks to numerous, small and short sparks. As a consequence, the titania films formed in the Ti +3 -containing solutions are relatively thick, more uniform, composed of almost pure crystalline anatase and rutile phases of TiO 2 , and contain a network of evenly distributed small pores. It has also been shown that these films are promising for applications in catalysis, sensors and optoelectronics. The Raman spectra indicate that an increase in the electrolysis time of titanium in the Ti +3 -containing solution leads to the increase in rutile content, as expected

  13. In situ synthesis of TiB2-TiC particulates locally reinforced medium carbon steel-matrix composites via the SHS reaction of Ni-Ti-B4C system during casting

    International Nuclear Information System (INIS)

    Wang, H.Y.; Huang, L.; Jiang, Q.C.

    2005-01-01

    The fabrication of medium carbon steel-matrix composites locally reinforced with in situ TiB 2 -TiC particulates using self-propagating high-temperature synthesis (SHS) reaction of Ni-Ti-B 4 C system during casting was investigated. X-ray diffraction (XRD) results reveal that the exotherm of 1042 deg. C initiated by heat release of the solid state reaction in the differential thermal analysis (DTA) curve is an incomplete reaction in Ni-Ti-B 4 C system. As-cast microstructures of the in situ processed composites reveal a relatively uniform distribution of TiB 2 -TiC particulates in the locally reinforced regions. Furthermore, the particulate size and micro-porosity in the locally reinforced regions are significantly decreased with the increasing of the Ni content in the preforms. For a Ni content of 30 and 40 wt.%, near fully dense composites locally reinforced with in situ TiB 2 and TiC particulates can be fabricated. Although most of fine TiB 2 and TiC particulates which form by the reaction-precipitation mechanism during SHS reaction are present in the locally reinforced region, some large particulates which form by the nucleation-growth mechanism during solidification are entrapped inside the Fe-rich region located in the reinforcing region or inside the matrix region nearby the interface between matrix and reinforcing region. The hardness of the reinforcing region in the composite is significantly higher than that of the unreinforced medium carbon steel. Furthermore, the hardness values of the composites synthesized from 30 to 40 wt.% Ni-Ti-B 4 C systems are higher than those of the composites synthesized from 10 to 20 wt.% Ni-Ti-B 4 C systems

  14. Effects of surface treatments on bond strength of dental Ti-20Cr and Ti-10Zr alloys to porcelain

    International Nuclear Information System (INIS)

    Lin, Hsi-Chen; Wu, Shih-Ching; Ho, Wen-Fu; Huang, Ling-Hsiu; Hsu, Hsueh-Chuan

    2010-01-01

    The purpose of this study was to investigate the effect of surface treatments, including sandblasting and grinding, on the bond strength between a low-fusing porcelain and c.p. Ti, Ti-20Cr and Ti-10Zr alloys. The surface treatments were divided into 2 groups. Grinding surface treatment was applied to the first group, which served as the control, and sandblasting was applied to the second group. After treatment, low-fusing porcelain (Titankeramik) was fired onto the surface of the specimens. A universal testing machine was used to perform a 3-point bending test. The metal-ceramic interfaces were subjected to scanning electron microscopic analysis. Of the sandblasted samples, the debonding test showed that Ti-20Cr alloy had the strongest (31.50 MPa) titanium-ceramic bond (p < 005), followed by c.p. Ti (29.4 MPa) and Ti-10Zr (24.3 MPa). Of the grinded samples, Ti-20Cr alloy showed 27.3 MPa titanium-ceramic bond (p < 005), followed by c.p. Ti (14.3 MPa) and Ti-10Zr (failure). The SEM micrographs of the metal surface after debonding showed residual porcelain retained on all samples. On the whole, sandblasting surface treatment appears to have had a more beneficial effect on the Ti-ceramic bond strength than grinding surface treatment. Furthermore, surface treatment of Ti-20Cr with either grinding or sandblasting resulted in adequate bond strength, which exceeded the lower limit value in the ISO 9693 standard (25 MPa).

  15. Adhesion and fracture toughness at α-Ti(0 0 0 1)/TiC(1 1 1): A first-principles investigation

    International Nuclear Information System (INIS)

    Li, Jian; Yang, Yanqing; Feng, Guanghai; Luo, Xian; Sun, Qing; Jin, Na

    2013-01-01

    The interfacial properties of α-Ti(0 0 0 1)/TiC(1 1 1) interface, such as adhesion, interface energy, interfacial fracture toughness, bonding nature, are investigated using first-principles calculations. Six interface models with different TiC(1 1 1) termination and stacking sites are investigated to clarify their influence on the interfacial stability and adhesion strength. C-terminated-hollow-site and Ti-terminated-center-site models exhibit identical epitaxial stacking style after fully relaxation, and can be regarded as the Ti and TiC sides of the most stable and strongest interface. The possible negative interface energy indicates the interfacial diffusion, and even new phase formation, is likely to happen across the interface. The largest interfacial fracture toughness is estimated about 4.8 MPa m 1/2 . The valence electron density and partial density of states (PDOS) indicate that its interfacial bonding is mainly contributed from C-Ti covalent bonds and Ti-Ti metallic interaction.

  16. Structure determinations for Ca3Ti2O7, Ca4Ti3O10, Ca3.6Sr0.4Ti3O10 and a refinement of Sr3Ti2O7

    International Nuclear Information System (INIS)

    Elcombe, M.M.; Kisi, E.H.; Hawkins, K.D.; White, T.J.; Goodman, P.; Matheson, S.

    1991-01-01

    The structures of the orthorhombic Ruddlesden-Popper (A n+1 B n X 3n+1 ) phases Ca 3 Ti 2 O 7 (n=2) refined from neutron powder diffraction data at λ=1.893 A. They consist of coherent intergrowths of perovskite (CaTiO 3 ) blocks, n TiO 6 octahedra thick, with single layers of CaO having a distorted NaCl configuration. TiO 6 octahedra are tilted and distorted in a very similar fashion to those in CaTiO 3 (n=∞). This fact was used to determine the space groups of the layered structures. Convergent-beam electron diffraction patterns are best matched by calculations in the above space groups which are thus confirmed. Octahedral tilt angles increase slightly in the sequence n=2, 3, ∞. Strontium addition reduces the octahedral tilt angles because of preferential substitution of Sr on the Ca sites within the perovskite blocks of Ca 4 Ti 3 O 10 . The algorithm used to produce starting models for structure refinements is thought to be generally applicable to Ruddlesden-Popper and possibly other layered perovskite structures. It furnishes the predictions: (a) all n-even compounds in the Ca n+1 Ti n O 3n+1 series will have space group Ccm2 1 , (b) all n-odd compounds in this series will have space group Pcab, (c) all A n+1 B n X 3n+1 series for which the n=∞ end member (ABX 3 ) is isostructural with CaTiO 3 will be isostructural with the compounds reported above (e.g. Ca n+1 Zr n O 3n+1 ). (orig./WL)

  17. 47,49Ti NMR: hyperfine interactions in oxides and metals.

    Science.gov (United States)

    Bastow, T J; Gibson, M A; Forwood, C T

    1998-10-01

    A 47,49Ti NMR characterisation is given of various polymorphs of TiO2 (anatase, rutile and brookite), Ti2O3, perovskites CaTiO3 and BaTiO3, FeTiO3, TiB2, titanium metal, the titanium aluminides Ti3Al, TiAl, TiAl2, TiAl3, and TiAg. Values of chemical or Knight shift, nuclear quadrupole coupling constant and asymmetry parameter were derived from the (1/2, -1/2) powder lineshapes. For TiB2, titanium metal, TiAl, and TiAl3, where +/- (1/2, 3/2), and higher satellite transitions were observed, a value for the axial component of the Knight shift was obtained.

  18. Hydrazine-based synergistic Ti(III)/N doping of surfactant-templated TiO{sub 2} thin films for enhanced visible light photocatalysis

    Energy Technology Data Exchange (ETDEWEB)

    Islam, Syed Z.; Rankin, Stephen E., E-mail: srankin@engr.uky.edu

    2016-10-01

    This study reports the preparation of titanium (Ti{sup 3+}) and nitrogen co-doped cubic ordered mesoporous TiO{sub 2} thin films using N{sub 2}H{sub 4} treatment. The resulting co-doped TiO{sub 2} (Ti{sup 3+}-N-TiO{sub 2}) thin films show significant enhancements in visible light absorption and photocatalytic activity. Cubic ordered mesoporous TiO{sub 2} thin films were prepared via a sol-gel method with Pluronic F127 as the pore template. After brief calcination, the TiO{sub 2} films were dipped into hydrazine hydrate which acts both as a nitrogen source and as a reducing agent, followed by heating at low temperature (90 °C). The hydrazine treatment period was varied from 5 to 20 h to obtain different degrees of reduction and nitrogen doping. X-ray photoelectron spectroscopy (XPS) analyses and UV–vis absorbance spectra of Ti{sup 3+}-N-TiO{sub 2} films indicate that the incorporated N atoms and Ti{sup 3+} reduce the band gap of TiO{sub 2} and thus enhance the absorption of visible light. The corresponding visible light photocatalytic activity of Ti{sup 3+}-N-TiO{sub 2} films was determined from the photocatalytic degradation of methylene blue under visible light illumination (at 455 nm). The Ti{sup 3+}-N-TiO{sub 2} films prepared with 10 h of treatment show the optimum photocatalytic activity, with a pseudo-first order rate coefficient of 0.12 h{sup −1}, which is 3 times greater than that of undoped TiO{sub 2} films. Calcination temperature and time were varied prior to hydrazine treatment to confirm that a brief calcination at low temperature (10 min at 350 °C) gave the best photochemical activity. In photoelectrochemical water oxidation using a 455 nm LED, the Ti{sup 3+}-N-TiO{sub 2} films prepared with 10 h of N{sub 2}H{sub 4} treatment show about 4 times the photocurrent compared to undoped TiO{sub 2} films. The present study suggests that hydrazine induced doping is a promising approach to enable synergistic incorporation of N and Ti{sup 3+} into the

  19. Grain refining efficiency of Al-Ti-C alloys

    International Nuclear Information System (INIS)

    Birol, Yuecel

    2006-01-01

    The problems associated with boride agglomeration and the poisoning effect of Zr in Zr-bearing alloys have created a big demand for boron-free grain refiners. The potential benefits of TiC as a direct nucleant for aluminium grains have thus generated a great deal of interest in TiC-bearing alloys in recent years. In Al-Ti-C grain refiners commercially available today, Al 3 Ti particles are introduced into the melt along with the TiC particles. Since the latter are claimed to nucleate α-Al directly, it is of great technological interest to see if reducing the Ti:C ratio further, i.e., increasing the C content of the grain refiner, will produce an increase in the grain refining efficiency of these alloys. A series of grain refiner samples with the Ti concentration fixed at 3% and a range of C contents between 0 and 0.75 were obtained by appropriately mixing an experimental Al-3Ti-0.75C alloy with Al-10Ti alloy and commercial purity aluminium. The grain refining efficiency of these grain refiners was assessed to investigate the role of the insoluble TiC and the soluble Al 3 Ti particles. The optimum chemistry for the Al-Ti-C grain refiners was also identified

  20. Grain refining efficiency of Al-Ti-C alloys

    Energy Technology Data Exchange (ETDEWEB)

    Birol, Yuecel [Materials Institute, Marmara Research Center, TUBITAK, 41470 Gebze, Kocaeli (Turkey)]. E-mail: yucel.birol@mam.gov.tr

    2006-09-28

    The problems associated with boride agglomeration and the poisoning effect of Zr in Zr-bearing alloys have created a big demand for boron-free grain refiners. The potential benefits of TiC as a direct nucleant for aluminium grains have thus generated a great deal of interest in TiC-bearing alloys in recent years. In Al-Ti-C grain refiners commercially available today, Al{sub 3}Ti particles are introduced into the melt along with the TiC particles. Since the latter are claimed to nucleate {alpha}-Al directly, it is of great technological interest to see if reducing the Ti:C ratio further, i.e., increasing the C content of the grain refiner, will produce an increase in the grain refining efficiency of these alloys. A series of grain refiner samples with the Ti concentration fixed at 3% and a range of C contents between 0 and 0.75 were obtained by appropriately mixing an experimental Al-3Ti-0.75C alloy with Al-10Ti alloy and commercial purity aluminium. The grain refining efficiency of these grain refiners was assessed to investigate the role of the insoluble TiC and the soluble Al{sub 3}Ti particles. The optimum chemistry for the Al-Ti-C grain refiners was also identified.

  1. Direct shoot regeneration via organogenesis in chieh- qua ...

    African Journals Online (AJOL)

    ajl6

    2013-11-27

    qua is an Asiatic crop widely farmed throughout southern China and Southeast Asia with a cultivation history of more than 300 years. ... genotype, explant type, seedling age, culture medium, concentration and a combination of ...

  2. Rotationally resolved state-to-state photoionization and photoelectron study of titanium carbide and its cation (TiC/TiC+)

    International Nuclear Information System (INIS)

    Luo, Zhihong; Huang, Huang; Chang, Yih-Chung; Zhang, Zheng; Ng, C. Y.; Yin, Qing-Zhu

    2014-01-01

    Titanium carbide and its cation (TiC/TiC + ) have been investigated by the two-color visible (VIS)-ultraviolet (UV) resonance-enhanced photoionization and pulsed field ionization-photoelectron (PFI-PE) methods. Two visible excitation bands for neutral TiC are observed at 16 446 and 16 930 cm −1 . Based on rotational analyses, these bands are assigned as the respective TiC( 3 Π 1 ) ← TiC(X 3 Σ + ) and TiC( 3 Σ + ) ← TiC(X 3 Σ + ) transition bands. This assignment supports that the electronic configuration and term symmetry for the neutral TiC ground state are …7σ 2 8σ 1 9σ 1 3π 4 (X 3 Σ + ). The rotational constant and the corresponding bond distance of TiC(X 3 Σ + ; v″ = 0) are determined to be B 0 ″ = 0.6112(10) cm −1 and r 0 ″ = 1.695(2) Å, respectively. The rotational analyses of the VIS-UV-PFI-PE spectra for the TiC + (X; v + = 0 and 1) vibrational bands show that the electronic configuration and term symmetry for the ionic TiC + ground state are …7σ 2 8σ 1 3π 4 (X 2 Σ + ) with the v + = 0 → 1 vibrational spacing of 870.0(8) cm −1 and the rotational constants of B e + = 0.6322(28) cm −1 , and α e + = 0.0085(28) cm −1 . The latter rotational constants yield the equilibrium bond distance of r e + = 1.667(4) Å for TiC + (X 2 Σ + ). The cleanly rotationally resolved VIS-UV-PFI-PE spectra have also provided a highly precise value of 53 200.2(8) cm −1 [6.5960(1) eV] for the adiabatic ionization energy (IE) of TiC. This IE(TiC) value along with the known IE(Ti) has made possible the determination of the difference between the 0 K bond dissociation energy (D 0 ) of TiC + (X 2 Σ + ) and that of TiC(X 3 Σ + ) to be D 0 (Ti + −C) − D 0 (Ti−C) = 0.2322(2) eV. Similar to previous experimental observations, the present state-to-state PFI-PE study of the photoionization transitions, TiC + (X 2 Σ + ; v + = 0 and 1, N + ) ← TiC( 3 Π 1 ; v′, J′), reveals a strong decreasing trend for the photoionization cross

  3. Modeling and calculation of RKKY exchange coupling to explain Ti-vacancy-induced ferromagnetism in Ta-doped TiO2

    Science.gov (United States)

    Majidi, Muhammad Aziz; Bupu, Annamaria; Fauzi, Angga Dito

    2017-12-01

    We present a theoretical study on Ti-vacancy-induced ferromagnetism in anatase TiO2. A recent experimental study has revealed room temperature ferromagnetism in Ta-doped anatase TiO2thin films (Rusydi et al., 2012) [7]. Ta doping assists the formation of Ti vacancies which then induce the formation of localized magnetic moments around the Ti vacancies. As neighboring Ti vacancies are a few unit cells apart, the ferromagnetic order is suspected to be mediated by itinerant electrons. We propose that such an electron-mediated ferromagnetism is driven by Ruderman-Kittel-Kasuya-Yosida (RKKY) exchange interaction. To examine our hypothesis, we construct a tight-binding based model Hamiltonian for the anatase TiO2 system. We calculate the RKKY exchange coupling constant of TiO2 as a function of distance between local magnetic moments at various temperatures. We model the system by taking only the layer containing a unit of TiO2, at which the Ti vacancy is believed to form, as our effective two-dimensional unit cell. Our model incorporates the Hubbard repulsive interactions between electrons occupying Ti d orbitals treated within mean-field approximation. The density of states profile resulting from the model captures the relevant electronic properties of TiO2, such as the energy gap of 3.4 eV and the n-type character, which may be a measure of the adequacy of the model. The calculated RKKY coupling constant shows that the ferromagnetic coupling extends up to 3-4 unit cells and enhances slightly as temperature is increased from 0 to 400 K. These results support our hypothesis that the ferromagnetism of this system is driven by RKKY mechanism.

  4. Synergistic effects between TiO2 and carbon nanotubes (CNTs) in a TiO2/CNTs system under visible light irradiation.

    Science.gov (United States)

    Wu, Chung-Hsin; Kuo, Chao-Yin; Chen, Shih-Ting

    2013-01-01

    This study synthesized a TiO2/carbon nanotubes (CNTs) composite via the sol-gel method. The surface characteristics of the TiO2/CNTs composite were determined by X-ray diffraction, transmission electron microscopy, specific surface area analyser, ultraviolent (UV)-vis spectroscopy, X-ray photoelectron spectroscopy and Raman spectrometer. The photocatalytic activity ofthe TiO2/CNTs composite was evaluated by decolourizing C.I. Reactive Red 2 (RR2) under visible light irradiation. Furthermore, the effects of calcination temperature, pH, RR2 concentration, and the TiO2/CNTs composite dosage on RR2 decolourization were determined simultaneously. The optimal calcination temperature to generate TiO2 and the TiO2/CNTs composite was 673 K, as the percentage of anatase crystallization at this temperature was highest. The specific surface area of the TiO2/CNTs composite and TiO2 were 45 and 42 m2/g, respectively. The band gap of TiO2 and the TiO2/CNTs composite was 2.97 and 2.71 eV by UV-vis measurements, respectively. Experimental data indicate that the Ti-O-C bond formed in the TiO2/CNTs composite. The RR2 decolourization rates can be approximated by pseudo-first-order kinetics; moreover, only the TiO2/CNTs composite had photocatalytic activity under visible light irradiation. At pH 7, the RR2 decolourization rate constant of 0.5, 1 and 2 g/L TiO2/CNTs addition was 0.005, 0.0015, and 0.0047 min(-1), respectively. Decolourization rate increased as pH and the RR2 concentration decreased. The CNTs functioned as electron acceptors, promoting separation of photoinduced electron-hole pairs to retard their recombination; thus, photocatalytic activity of the TiO2/CNTs composite exceeded that of TiO2.

  5. Novel GIMS technique for deposition of colored Ti/TiO₂ coatings on industrial scale

    Directory of Open Access Journals (Sweden)

    Zdunek Krzysztof

    2016-03-01

    Full Text Available The aim of the present paper has been to verify the effectiveness and usefulness of a novel deposition process named GIMS (Gas Injection Magnetron Sputtering used for the flrst time for deposition of Ti/TiO₂ coatings on large area glass Substrates covered in the condition of industrial scale production. The Ti/TiO₂ coatings were deposited in an industrial System utilizing a set of linear magnetrons with the length of 2400 mm each for covering the 2000 × 3000 mm glasses. Taking into account the speciflc course of the GIMS (multipoint gas injection along the magnetron length and the scale of the industrial facility, the optical coating uniformity was the most important goal to check. The experiments on Ti/TiO₂ coatings deposited by the use of GIMS were conducted on Substrates in the form of glass plates located at the key points along the magnetrons and intentionally non-heated during any stage of the process. Measurements of the coatings properties showed that the thickness and optical uniformity of the 150 nm thick coatings deposited by GIMS in the industrial facility (the thickness differences on the large plates with 2000 mm width did not exceed 20 nm is fully acceptable form the point of view of expected applications e.g. for architectural glazing.

  6. Rotationally resolved state-to-state photoionization and photoelectron study of titanium carbide and its cation (TiC/TiC⁺).

    Science.gov (United States)

    Luo, Zhihong; Huang, Huang; Chang, Yih-Chung; Zhang, Zheng; Yin, Qing-Zhu; Ng, C Y

    2014-10-14

    Titanium carbide and its cation (TiC/TiC(+)) have been investigated by the two-color visible (VIS)-ultraviolet (UV) resonance-enhanced photoionization and pulsed field ionization-photoelectron (PFI-PE) methods. Two visible excitation bands for neutral TiC are observed at 16,446 and 16,930 cm(-1). Based on rotational analyses, these bands are assigned as the respective TiC((3)Π1) ← TiC(X(3)Σ(+)) and TiC((3)Σ(+)) ← TiC(X(3)Σ(+)) transition bands. This assignment supports that the electronic configuration and term symmetry for the neutral TiC ground state are …7σ(2)8σ(1)9σ(1)3π(4) (X(3)Σ(+)). The rotational constant and the corresponding bond distance of TiC(X(3)Σ(+); v″ = 0) are determined to be B0″ = 0.6112(10) cm(-1) and r0″ = 1.695(2) Å, respectively. The rotational analyses of the VIS-UV-PFI-PE spectra for the TiC(+)(X; v(+) = 0 and 1) vibrational bands show that the electronic configuration and term symmetry for the ionic TiC(+) ground state are …7σ(2)8σ(1)3π(4) (X(2)Σ(+)) with the v(+) = 0 → 1 vibrational spacing of 870.0(8) cm(-1) and the rotational constants of B(e)(+) = 0.6322(28) cm(-1), and α(e)(+) = 0.0085(28) cm(-1). The latter rotational constants yield the equilibrium bond distance of r(e)(+) = 1.667(4) Å for TiC(+)(X(2)Σ(+)). The cleanly rotationally resolved VIS-UV-PFI-PE spectra have also provided a highly precise value of 53 200.2(8) cm(-1) [6.5960(1) eV] for the adiabatic ionization energy (IE) of TiC. This IE(TiC) value along with the known IE(Ti) has made possible the determination of the difference between the 0 K bond dissociation energy (D0) of TiC(+)(X(2)Σ(+)) and that of TiC(X(3)Σ(+)) to be D0(Ti(+)-C) - D0(Ti-C) = 0.2322(2) eV. Similar to previous experimental observations, the present state-to-state PFI-PE study of the photoionization transitions, TiC(+)(X(2)Σ(+); v(+) = 0 and 1, N(+)) ← TiC((3)Π1; v', J'), reveals a strong decreasing trend for the photoionization cross section as |ΔN(+)| = |N

  7. Induced Ti magnetization at La0.7Sr0.3MnO3 and BaTiO3 interfaces

    Directory of Open Access Journals (Sweden)

    Yaohua Liu

    2016-04-01

    Full Text Available In artificial multiferroics hybrids consisting of ferromagnetic La0.7Sr0.3MnO3 (LSMO and ferroelectric BaTiO3 epitaxial layers, net Ti moments are found from polarized resonant soft x-ray reflectivity and absorption. The Ti dichroic reflectivity follows the Mn signal during the magnetization reversal, indicating exchange coupling between the Ti and Mn ions. However, the Ti dichroic reflectivity shows stronger temperature dependence than the Mn dichroic signal. Besides a reduced ferromagnetic exchange coupling in the interfacial LSMO layer, this may also be attributed to a weak Ti-Mn exchange coupling that is insufficient to overcome the thermal energy at elevated temperatures.

  8. Effects of sintering and paste-baking conditions on PTCR characteristic of (Ba,Sr)TiO{sub 3} vacuum-sintered compact added with TiO{sub 2}(Ti) powder; TiO{sub 2}(ti) fun tenka (Ba,Sr)TiO{sub 3} shinku shoketsutai no PTCR tokusei ni oyobosu shoketsu oyobi paste yakitsuke joken no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J.; Hayashi, K. [The University of Tokyo, Tokyo (Japan). Institute of Industrial Science

    1999-04-15

    The effects of sintering temperature (T{sub s}; 1,573 {approx} 1,748K) and time (t{sub s}; 0.6 {approx} 14.4ks) and paste-baking-temperature or heating temperature (T{sub b} or T{sub h}; 673 {approx} 1,273K; t{sub b} is 0.3ks) on PTCR characteristic were investigated for (Ba, Sr)TiO{sub 3} vacuum-sintered compact added with 3.9mass% TiO{sub 2}(Ti) powder of 12.5mass% TiO{sub 2}. The results obtained were as follows; (1) PTCR characteristic developed at all T{sub s} (t{sub s}=3.6ks, T{sub b}=853K). The electrical resistivity at room temperature ({rho}{sub rt}) showed a minimum value of 1.8 times 10{sup 2}ohmcenter dotcm and the {rho}{sub max}/{rho}{sub rt} showed a maximum value of about 10{sup 6} at 1,723K. (2)For all t{sub s} (T{sub s}=1,623K, T{sub b}=853K), PTCR characteristic developed. The {rho}{sub rt} showed a minimum value of 2.6 times 10{sup 3}ohmcenter dotcm at 7.2ks. (3) At T{sub b} above 823K (T{sub s}=1,623K, t{sub s}=3.6ks), PTCR characteristic developed. The {rho}{sub rt} showed a minimum value of 1.0 times 10{sup 3}ohmcenter dotcm. (4)The {rho}-T curve of (Ba, Sr)TiO{sub 3}+TiO{sub 2}(Ti) vacuum-sintered compact was affected more largely by T{sub s}, t{sub s} and T{sub b} than that of (Ba, Sr)TiO{sub 3} air-sintered compact. This was considered to be mainly due to the porous and fine gained microstructure in the former compact. (author)

  9. Solution-Processed Ultrathin TiO2 Compact Layer Hybridized with Mesoporous TiO2 for High-Performance Perovskite Solar Cells.

    Science.gov (United States)

    Jeong, Inyoung; Park, Yun Hee; Bae, Seunghwan; Park, Minwoo; Jeong, Hansol; Lee, Phillip; Ko, Min Jae

    2017-10-25

    The electron transport layer (ETL) is a key component of perovskite solar cells (PSCs) and must provide efficient electron extraction and collection while minimizing the charge recombination at interfaces in order to ensure high performance. Conventional bilayered TiO 2 ETLs fabricated by depositing compact TiO 2 (c-TiO 2 ) and mesoporous TiO 2 (mp-TiO 2 ) in sequence exhibit resistive losses due to the contact resistance at the c-TiO 2 /mp-TiO 2 interface and the series resistance arising from the intrinsically low conductivity of TiO 2 . Herein, to minimize such resistive losses, we developed a novel ETL consisting of an ultrathin c-TiO 2 layer hybridized with mp-TiO 2 , which is fabricated by performing one-step spin-coating of a mp-TiO 2 solution containing a small amount of titanium diisopropoxide bis(acetylacetonate) (TAA). By using electron microscopies and elemental mapping analysis, we establish that the optimal concentration of TAA produces an ultrathin blocking layer with a thickness of ∼3 nm and ensures that the mp-TiO 2 layer has a suitable porosity for efficient perovskite infiltration. We compare PSCs based on mesoscopic ETLs with and without compact layers to determine the role of the hole-blocking layer in their performances. The hybrid ETLs exhibit enhanced electron extraction and reduced charge recombination, resulting in better photovoltaic performances and reduced hysteresis of PSCs compared to those with conventional bilayered ETLs.

  10. Mechanical and tribological properties of Ti-containing carbon nanocomposite coatings deposited on TiAlV alloys

    Directory of Open Access Journals (Sweden)

    Emanuel Santos Júnior

    2010-12-01

    Full Text Available Ti-doped carbon coatings were deposited on TiAlV alloys by reactive dc-magnetron sputtering in Ar/CH4 mixed gas. When Ar flow increases the incorporation of Ti into films raises while the concentration of C decreases. The formed nanometric TiC crystals were more noticeable for coatings deposited with higher Ar flows. Hardness (H and elastic modulus (E of coatings were measured by nanoindentation. H values were in the range of 8.8-15.9 GPa and E of 53.4-113.7 GPa. Higher values for H and E were obtained for films containing larger amount of TiC-phase. The presence of TiC crystals increased the coefficient of friction (COF from 0.07 to 0.28 in scratch tests. Tribological experiments were carried out by using a pin-on-disk apparatus in air and in liquid. COF values ranged from 0.10 to 0.50 for tests in air. Despite of presenting higher COF, tests performed in liquid resulted in less pronounced wear tracks.

  11. Structural heredity of TiC and its influences on refinement behaviors of AlTiC master alloy

    Institute of Scientific and Technical Information of China (English)

    王振卿; 刘相法; 柳延辉; 张均燕; 于丽娜; 边秀房

    2003-01-01

    Heredity of microstructure in AlTiC master alloy, grain refiners, was analyzed. It is found that, for morphologies and distributions of TiC particles, there are visible heredity which originates from raw materials or processing methods of Al melt, and will ultimately be transferred to the solid state structure through the melt stage, and this phenomenon can cause hereditary influences on refinement: formation of chain-like TiC morphology results in rapid refinement fading behavior; distribution of TiC along grain boundaries greatly reduces refinement efficiency. Controlling of structural heredity through proper selections of raw materials and processing parameters is of great importance in obtaining ideal microstructures and improving refinement behaviors of AlTiC master alloys.

  12. Biocorrosion studies of TiO2 nanoparticle-coated Ti-6Al-4V implant in simulated biofluids

    International Nuclear Information System (INIS)

    Zaveri, Nikita; McEwen, Gerald D.; Karpagavalli, Ramji; Zhou Anhong

    2010-01-01

    The corrosion behaviors of the TiO 2 nanoparticles coated bioimplant Ti-6Al-4V exposed to three different simulated biofluids (SBF), namely, (1) NaCl solution, (2) Hank's solution, and (3) Cigada solution, were studied by using micro-Raman spectroscopy, electrochemical techniques, and scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS). The different electrochemical impedance spectroscopy models were applied to fit the data obtained from the implants before and after the coating of TiO 2 nanoparticles (50-100 nm). It was found that the TiO 2 nanoparticle coatings increased the thickness of the pre-existing oxide layer on the Ti-6Al-4V surface, serving to improve the bioimplant corrosion resistance.

  13. Biocorrosion studies of TiO2 nanoparticle-coated Ti-6Al-4V implant in simulated biofluids

    Science.gov (United States)

    Zaveri, Nikita; McEwen, Gerald D.; Karpagavalli, Ramji; Zhou, Anhong

    2010-06-01

    The corrosion behaviors of the TiO2 nanoparticles coated bioimplant Ti-6Al-4V exposed to three different simulated biofluids (SBF), namely, (1) NaCl solution, (2) Hank's solution, and (3) Cigada solution, were studied by using micro-Raman spectroscopy, electrochemical techniques, and scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS). The different electrochemical impedance spectroscopy models were applied to fit the data obtained from the implants before and after the coating of TiO2 nanoparticles (50-100 nm). It was found that the TiO2 nanoparticle coatings increased the thickness of the pre-existing oxide layer on the Ti-6Al-4V surface, serving to improve the bioimplant corrosion resistance.

  14. Controllable solvothermal synthesis and photocatalytic properties of complex (oxy)fluorides K{sub 2}TiOF{sub 4}, K{sub 3}TiOF{sub 5}, K{sub 7}Ti{sub 4}O{sub 4}F{sub 7} and K{sub 2}TiF{sub 6}

    Energy Technology Data Exchange (ETDEWEB)

    Sheng Jie [Division of Nanomaterials and Nanochemistry, Hefei National Laboratory for Physical Sciences at Microscale, Hefei, Anhui 230026 (China); Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026 (China); Tang Kaibin, E-mail: kbtang@ustc.edu.cn [Division of Nanomaterials and Nanochemistry, Hefei National Laboratory for Physical Sciences at Microscale, Hefei, Anhui 230026 (China); Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026 (China); Cheng Wei; Wang Junli; Nie Yanxiang; Yang Qing [Division of Nanomaterials and Nanochemistry, Hefei National Laboratory for Physical Sciences at Microscale, Hefei, Anhui 230026 (China); Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026 (China)

    2009-11-15

    Complex (oxy)fluorides K{sub 2}TiF{sub 6}, K{sub 2}TiOF{sub 4}, K{sub 3}TiOF{sub 5} and K{sub 7}Ti{sub 4}O{sub 4}F{sub 7} have been successfully synthesized for the first time through a controllable solvothermal route involving different solvents, for example, methanol, methanol-H{sub 2}O and methanol-H{sub 2}O{sub 2}. The as-prepared products were characterized by X-ray powder diffraction, N{sub 2} surface area adsorption, scanning electron microscope, Fourier transform infrared spectroscopy, UV-vis absorption spectra and X-ray fluorescence. The influences of reaction conditions such as the ratio of methanol to H{sub 2}O{sub 2} or methanol to H{sub 2}O, reaction temperature on the phase, crystallizability and purity of the (oxy)fluorides products were discussed in detail. Meanwhile, the photocatalytic behaviors of the as-prepared K{sub 2}TiF{sub 6}, K{sub 2}TiOF{sub 4}, K{sub 3}TiOF{sub 5} and K{sub 7}Ti{sub 4}O{sub 4}F{sub 7} were evaluated by degradation of rhodamine B molecules, and the results showed that all of the products possessed photocatalytic activities in the order of K{sub 2}TiOF{sub 4} > K{sub 2}TiF{sub 6} > K{sub 7}Ti{sub 4}O{sub 4}F{sub 7} > K{sub 3}TiOF{sub 5} at room temperature under the UV light.

  15. Characterization of Al/Ni multilayers and their application in diffusion bonding of TiAl to TiC cermet

    Energy Technology Data Exchange (ETDEWEB)

    Cao, J., E-mail: cao_jian@hit.edu.cn [State Key Lab of Advanced Welding Production Technology, Harbin Institute of Technology, Harbin, 150001 (China); Center for Composite Materials and Structures, Harbin Institute of Technology, Harbin, 150001 (China); Song, X.G. [State Key Lab of Advanced Welding Production Technology, Harbin Institute of Technology, Harbin, 150001 (China); Wu, L.Z. [Center for Composite Materials and Structures, Harbin Institute of Technology, Harbin, 150001 (China); Qi, J.L.; Feng, J.C. [State Key Lab of Advanced Welding Production Technology, Harbin Institute of Technology, Harbin, 150001 (China)

    2012-02-29

    The Al/Ni multilayers were characterized and diffusion bonding of TiAl intermetallics to TiC cermets was carried out using the multilayers. The microstructure of Al/Ni multilayers and TiAl/TiC cermet joint was investigated. The layered structures consisting of a Ni{sub 3}(AlTi) layer, a Ni{sub 2}AlTi layer, a (Ni,Al,Ti) layer and a Ni diffusion layer were observed from the interlayer to the TiAl substrate. Only one AlNi{sub 3} layer formed at the multilayer/TiC cermet interface. The reaction behaviour of Al/Ni multilayers was characterized by means of differential scanning calorimeter (DSC) and X-ray diffraction. The initial exothermic peak of the DSC curve was formed due to the formation of Al{sub 3}Ni and Al{sub 3}Ni{sub 2} phases. The reaction sequence of the Al/Ni multilayers was Al{sub 3}Ni {yields} Al{sub 3}Ni{sub 2} {yields} AlNi {yields} AlNi{sub 3} and the final products were AlNi and AlNi{sub 3} phases. The shear strength of the joint was tested and the experimental results suggested that the application of Al/Ni multilayers improved the joining quality. - Highlights: Black-Right-Pointing-Pointer Diffusion bonding of TiAl to TiC cermet was realized using Al/Ni multilayer. Black-Right-Pointing-Pointer The reaction sequence of the Al/Ni multilayers was Al{sub 3}Ni {yields} Al{sub 3}Ni{sub 2} {yields} AlNi {yields} AlNi{sub 3}. Black-Right-Pointing-Pointer The interfacial microstructure of the joint was clarified. Black-Right-Pointing-Pointer The application of Al/Ni multilayers improved the joining quality.

  16. Microstructural and mechanical characteristics of W–2Ti and W–1TiC processed by hot isostatic pressing

    Energy Technology Data Exchange (ETDEWEB)

    Muñoz, A., E-mail: angel.munoz@uc3m.es [Departamento de Física, Universidad Carlos III de Madrid, Avda. de la Universidad, 30, E28911 Leganés (Spain); Savoini, B. [Departamento de Física, Universidad Carlos III de Madrid, Avda. de la Universidad, 30, E28911 Leganés (Spain); Tejado, E. [Departamento de Ciencia de Materiales, E.T.S. I. de Ingenieros de Caminos, Canales y Puertos, Universidad Politécnica de Madrid, E28040 Madrid (Spain); Centro Nacional de Investigaciones Metalúrgicas (C.S.I.C), Av. Gregorio del Amo, 8, E2840 Madrid (Spain); Monge, M.A. [Departamento de Física, Universidad Carlos III de Madrid, Avda. de la Universidad, 30, E28911 Leganés (Spain); Pastor, J.Y. [Departamento de Ciencia de Materiales, E.T.S. I. de Ingenieros de Caminos, Canales y Puertos, Universidad Politécnica de Madrid, E28040 Madrid (Spain); Pareja, R. [Departamento de Física, Universidad Carlos III de Madrid, Avda. de la Universidad, 30, E28911 Leganés (Spain)

    2014-12-15

    W–2Ti and W–1TiC alloys were produced by mechanical alloying and consolidation by hot isostatic pressing. The composition and microstructural characteristics of these alloys were studied by X-ray diffraction, energy dispersion spectroscopy and scanning electron microscopy. The mechanical behavior of the consolidated alloys was characterized by microhardness measurements and three point bending tests. The mechanical characteristics of the W–2Ti alloy appear to be related to solution hardening. In W–1TiC, the residual porosity should be responsible for the poor behavior observed in comparison with W–2Ti.

  17. Microstructural and mechanical characteristics of W–2Ti and W–1TiC processed by hot isostatic pressing

    International Nuclear Information System (INIS)

    Muñoz, A.; Savoini, B.; Tejado, E.; Monge, M.A.; Pastor, J.Y.; Pareja, R.

    2014-01-01

    W–2Ti and W–1TiC alloys were produced by mechanical alloying and consolidation by hot isostatic pressing. The composition and microstructural characteristics of these alloys were studied by X-ray diffraction, energy dispersion spectroscopy and scanning electron microscopy. The mechanical behavior of the consolidated alloys was characterized by microhardness measurements and three point bending tests. The mechanical characteristics of the W–2Ti alloy appear to be related to solution hardening. In W–1TiC, the residual porosity should be responsible for the poor behavior observed in comparison with W–2Ti

  18. Effects of TiN coating on the corrosion of nanostructured Ti-30Ta-xZr alloys for dental implants

    Science.gov (United States)

    Kim, Won-Gi; Choe, Han-Cheol

    2012-01-01

    Electrochemical characteristics of a titanium nitride (TiN)-coated/nanotube-formed Ti-Ta-Zr alloy for biomaterials have been researched by using the magnetic sputter and electrochemical methods. Ti-30Ta-xZr (x = 3, 7 and 15 wt%) alloys were prepared by arc melting and heat treated for 24 h at 1000 °C in an argon atmosphere and then water quenching. The formation of oxide nanotubes was achieved by anodizing a Ti-30Ta-xZr alloy in H3PO4 electrolytes containing small amounts of fluoride ions at room temperature. Anodization was carried out using a scanning potentiostat, and all experiments were conducted at room temperature. The microstructure and morphology of nanotube arrays were characterized by optical microscopy (OM), field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD). The TiN coatings were obtained by the radio-frequency (RF) magnetron sputtering technique. The depositions were performed from pure Ti targets on Ti-30Ta-xZr alloys substrates. The corrosion properties of the specimens were examined using potentiodynamic test in a 0.9% NaCl solution by using potentiostat. The microstructures of Ti-30Ta-xZr alloys were changed from an equiaxed to a needle-like structure with increasing Zr content. The interspace between the nanotubes was approximately 20, 80 and 200 nm for Zr contents of 3, 7 and 15 wt%, respectively. The corrosion resistance of the TiN-coated on the anodized Ti-30Ta-xZr alloys was higher than that of the untreated Ti alloys, indicating a better protective effect.

  19. Recovery characteristics of neutron-irradiated V-Ti alloys

    International Nuclear Information System (INIS)

    Leguey, T.; Pareja, R.

    2000-01-01

    The recovery characteristics of neutron-irradiated pure V and V-Ti alloys with 1.0 and 4.5 at.% Ti have been investigated by positron annihilation spectroscopy. Microvoid formation during irradiation at 320 K is produced in pure V and V-1Ti but not in V-4.5Ti. The results are consistent with a model of swelling inhibition induced by vacancy trapping by solute Ti during irradiation. The temperature dependencies of the parameter S in the range 8-300 K indicate a large dislocation bias for vacancies and solute Ti. This dislocation bias prevents the microvoid nucleation in V-4.5Ti, and the microvoid growth in V-1Ti, when vacancies become mobile during post-irradiation annealing treatments. A characteristic increase of the positron lifetime is found during recovery induced by isochronal annealing. It is attributed to a vacancy accumulation into the lattice of Ti oxides precipitated during cooling down, or at their matrix/precipitate interfaces. These precipitates could be produced by the decomposition of metastable phases of Ti oxides formed during post-irradiation annealing above 1000 K

  20. Morphology, deformation, and defect structures of TiCr2 in Ti-Cr alloys

    International Nuclear Information System (INIS)

    Chen, K.C.; Allen, S.M.; Livingston, J.D.

    1992-01-01

    The morphologies and defect structures of TiCr 2 in several Ti-Cr alloys have been examined by optical metallography, x-ray diffraction, and transmission electron microscopy (TEM), in order to explore the room-temperature deformability of the Laves phase TiCr 2 . The morphology of the Laves phase was found to be dependent upon alloy composition and annealing temperature. Samples deformed by compression have also been studied using TEM. Comparisons of microstructures before and after deformation suggest an increase in twin, stacking fault, and dislocation density within the Laves phase, indicating some but not extensive room-temperature deformability

  1. Grindability of cast Ti-Cu alloys.

    Science.gov (United States)

    Kikuchi, Masafumi; Takada, Yukyo; Kiyosue, Seigo; Yoda, Masanobu; Woldu, Margaret; Cai, Zhuo; Okuno, Osamu; Okabe, Toru

    2003-07-01

    The purpose of the present study was to evaluate the grindability of a series of cast Ti-Cu alloys in order to develop a titanium alloy with better grindability than commercially pure titanium (CP Ti), which is considered to be one of the most difficult metals to machine. Experimental Ti-Cu alloys (0.5, 1.0, 2.0, 5.0, and 10.0 mass% Cu) were made in an argon-arc melting furnace. Each alloy was cast into a magnesia mold using a centrifugal casting machine. Cast alloy slabs (3.5 mm x 8.5 mm x 30.5 mm), from which the hardened surface layer (250 microm) was removed, were ground using a SiC abrasive wheel on an electric handpiece at four circumferential speeds (500, 750, 1000, or 1250 m/min) at 0.98 N (100 gf). Grindability was evaluated by measuring the amount of metal volume removed after grinding for 1min. Data were compared to those for CP Ti and Ti-6Al-4V. For all speeds, Ti-10% Cu alloy exhibited the highest grindability. For the Ti-Cu alloys with a Cu content of 2% or less, the highest grindability corresponded to an intermediate speed. It was observed that the grindability increased with an increase in the Cu concentration compared to CP Ti, particularly for the 5 or 10% Cu alloys at a circumferential speed of 1000 m/min or above. By alloying with copper, the cast titanium exhibited better grindability at high speed. The continuous precipitation of Ti(2)Cu among the alpha-matrix grains made this material less ductile and facilitated more effective grinding because small broken segments more readily formed.

  2. In vitro and in vivo performance of bioactive Ti6Al4V/TiC/HA implants fabricated by a rapid microwave sintering technique

    International Nuclear Information System (INIS)

    Choy, Man Tik; Tang, Chak Yin; Chen, Ling; Wong, Chi Tak; Tsui, Chi Pong

    2014-01-01

    Failure of the bone–implant interface in a joint prosthesis is a main cause of implant loosening. The introduction of a bioactive substance, hydroxyapatite (HA), to a metallic bone–implant may enhance its fixation on human bone by encouraging direct bone bonding. Ti6Al4V/TiC/HA composites with a reproducible porous structure (porosity of 27% and pore size of 6–89 μm) were successfully fabricated by a rapid microwave sintering technique. This method allows the biocomposites to be fabricated in a short period of time under ambient conditions. Ti6Al4V/TiC/HA composites exhibited a compressive strength of 93 MPa, compressive modulus of 2.9 GPa and microhardness of 556 HV which are close to those of the human cortical bone. The in vitro preosteoblast MC3T3-E1 cells cultured on the Ti6Al4V/TiC/HA composite showed that the composite surface could provide a biocompatible environment for cell adhesion, proliferation and differentiation without any cytotoxic effects. This is among the first attempts to study the in vivo performance of load-bearing Ti6Al4V/TiC and Ti6Al4V/TiC/HA composites in a live rabbit. The results indicated that the Ti6Al4V/TiC/HA composite had a better bone–implant interface compared with the Ti6Al4V/TiC implant. Based on the microstructural features, the mechanical properties, and the in vitro and in vivo test results from this study, the Ti6Al4V/TiC/HA composites have the potential to be employed in load-bearing orthopedic applications. - Highlights: • Ti6Al4V/TiC and Ti6Al4V/TiC/HA composites were fabricated by microwave sintering. • Ti6Al4V/TiC/HA exhibited mechanical properties close to human cortical bone. • Ti6Al4V/TiC/HA could provide a biocompatible environment for bone cell growth. • Ti6Al4V/TiC/HA showed a better bone–implant interface than Ti6Al4V/TiC. • Ti6Al4V/TiC/HA could be used for bone replacement under load-bearing conditions

  3. Effects of the TiC Nanoparticle on Microstructures and Tensile Properties of Selective Laser Melted IN718/TiC Nanocomposites

    Science.gov (United States)

    Yao, Xiling; Moon, Seung Ki; Lee, Bing Yang; Bi, Guijun

    2018-03-01

    The purpose of this paper is to investigate the effects of TiC nanoparticle content on microstructures and tensile properties of the IN718/TiC nanocomposites fabricated by selective laser melting (SLM). 0.5wt%, 1.0wt%, and 2.0wt% of TiC nanoparticles are added to the IN718 powders. The bulk-form IN718/TiC nanocomposites with different TiC contents are fabricated in-situ by SLM using the same process settings. The evolution of microstructures and tensile properties as the effect of changing the TiC content is studied using the optical microscopy, scanning electron microscopy, X-ray diffraction analysis, and tensile testing. The increase of TiC content refines the microstructure, promotes the formation of the cellular morphology, and reduces the size and continuity of Laves precipitates. Increasing the TiC content improves the yield strength and ultimate tensile strength but decreases the ductility. The grain refinement, dislocation bowing, dislocation punching, and the reduction in Laves precipitate contribute to the strengthening effect in the IN718/TiC nanocomposites.

  4. Improved optical response and photocatalysis for N-doped titanium oxide (TiO2) films prepared by oxidation of TiN

    International Nuclear Information System (INIS)

    Wan, L.; Li, J.F.; Feng, J.Y.; Sun, W.; Mao, Z.Q.

    2007-01-01

    In order to improve the photocatalytic activity, N-doped titanium oxide (TiO 2 ) films were obtained by thermal oxidation of TiN films, which were prepared on Ti substrates by ion beam assisted deposition (IBAD). The dominating rutile TiO 2 phase was found in films after thermal oxidation. According to the results of X-ray photoelectron spectroscopy (XPS), the residual N atoms occupied O-atom sites in TiO 2 lattice to form Ti-O-N bonds. UV-vis spectra revealed the N-doped TiO 2 film had a red shift of absorption edge. The maximum red shift was assigned to the sample annealed at 750 deg. C, with an onset wavelength at 600 nm. The onset wavelength corresponded to the photon energy of 2.05 eV, which was nearly 1.0 eV below the band gap of pure rutile TiO 2 . The effect of nitrogen was responsible for the enhancement of photoactivity of N-doped TiO 2 films in the range of visible light

  5. Enhanced photocatalysts based on Ag-TiO2 and Ag-N-TiO2 nanoparticles for multifunctional leather surface coating

    Directory of Open Access Journals (Sweden)

    Gaidau Carmen

    2016-01-01

    Full Text Available The Ag deposition on TiO2 nanoparticles (Ag-TiO2 NPs and N-TiO2 nanoparticles (Ag-N-TiO2 NPs has been made by electrochemical methodology in view of improved antibacterial properties and enhanced photocatalytic activity under visible light irradiation. The particle size in powder and in dispersion showed similar values and good stability in aqueous medium which made them suitable for use in leather surface covering for new multifunctional properties development. The diffuse reflectance spectra of Ag-TiO2 NPs, Ag-N-TiO2 NPs and TiO2 NPs have been investigated and correlated with their photocatalytic performances under UV and visible light against different silver concentrations. The leather surfaces treated with Ag-N-TiO2 NPs showed advanced self-cleaning properties under visible light exposure through the hydrophilic mechanism of organic soil decomposition. Moreover the bacterial sensitivity and proven fungitoxic properties of Ag-N-TiO2 NPs leads to the possibility of designing new multifunctional additives to extend the advanced applications for more durable and useable materials.

  6. Microstructure, Wear Resistance and Oxidation Behavior of Ni-Ti-Si Coatings Fabricated on Ti6Al4V by Laser Cladding

    Directory of Open Access Journals (Sweden)

    Qiaoqiao Zhuang

    2017-10-01

    Full Text Available The Ni-Ti-Si composite coatings were successfully fabricated on Ti6Al4V by laser cladding. The microstructure were studied by SEM (scanning electron microscopy and EDS (energy dispersive spectrometer. It has been found that Ti2Ni and Ti5Si3 phases exist in all coatings, and some samples have TiSi2 phases. Moreover, due to the existence of these phases, coatings presented relatively higher microhardness than that of the substrate (826 HV (Vickers hardness and the microhardness value of coating 3 is about twice larger than that of the substrate. During the dry sliding friction and wear test, due to the distribution of the relatively ductile phase of Ti2Ni and reinforcement phases of Ti5Si3 and TiSi2, the coatings performed good wear resistance. The oxidation process contains two stages: the rapid oxidation and slow oxidation by high temperature oxidation test at 800 °C for 50 h. Meanwhile, the value of the oxidation weight gain of the substrate is approximately three times larger than that of the coating 4. During the oxidation process, the oxidation film formed on the coating is mainly consisted of TiO2, Al2O3 and SiO2. Phases Ti2Ni, Ti5Si3, TiSi2 and TiSi were still found and it could be responsible for the improvement in oxidation resistance of the coatings by laser cladding.

  7. Laser fabrication of Ti6Al4V/TiC composites using simultaneous powder and wire feed

    International Nuclear Information System (INIS)

    Wang, F.; Mei, J.; Jiang, H.; Wu, X.

    2007-01-01

    Composites of Ti-6Al-4V containing different volume fractions of TiC were manufactured using direct laser fabrication. Ti-6Al-4V wire and TiC powder were fed into the laser with the rate of powder feed being changed so that samples containing different volume fractions of TiC could be manufactured. Optical microscopy, scanning electron and transmission electron microscopy were used to characterise the microstructure of these samples. The room temperature tensile properties were measured also on some selected compositions together with their Young's moduli. In addition the change in wear resistance was studied as a function of TiC volume fraction using a standard wear test. These observations are discussed in terms of the advantages and difficulties of using simultaneous wire and powder feed systems and in terms of the value of this approach in obtaining data over a wide range of compositions for such a composite

  8. Synthesis of nano-TiO2 photocatalysts with tunable Fe doping concentration from Ti-bearing tailings

    Science.gov (United States)

    Sui, Yulei; Liu, Qingxia; Jiang, Tao; Guo, Yufeng

    2018-01-01

    In this work, highly pure nano-TiO2 photocatalysts with varying Fe doping concentration were successfully synthesized from low-cost Ti-bearing tailings by an acidolysis-hydrothermal route. The effects of H2SO4 concentration, leaching temperature, acid/tailings ratio and leaching time on the recovery of TiO2 from the tailings were investigated. Synthesized samples were characterized by XRD, TEM, EDS, XPS, and UV-vis spectroscopy. The results showed that the material prepared is characteristic anatase with the average size of 20 nm and the Fe doping concentration in the synthesized nano-TiO2 is tunable. The photocatalytic activity of synthesized nano-TiO2 photocatalyst was also evaluated by the photodegradation of Rhodamine B under visible light and UV light irradiation. Our study demonstrates a low-cost approach to synthesize highly efficient and visible light responsive catalysts.

  9. Reaction Synthesis of TiC Particle by Pressureless Sintering%无压烧结反应合成片状TiC晶粒

    Institute of Scientific and Technical Information of China (English)

    李新

    2013-01-01

    TiC particle was synthesized by heat treatment using 3TiC/Si/0.2Al powders. The phase composition and microstructure of the material was characterized by XRD and SEM. The composition of the sample was determined by EDS. The results show that the main phase of the product is Ti3SiC2 at 1100-1200 ℃. In addition, some amounts of TiC and SiC are also synthesized. At 1300℃ , Ti3SiC2 begins to decompose. When the temperature reaches 1350℃ , Ti3SiC2 totally decomposes into TiC. The product is mainly composed of TiC and small amounts of SiC. The length side of TiC hexagonal particle is 5 μm.%采用3TiC/Si/0.2A1粉体为原料,通过无压烧结反应合成了片状TiC晶粒.采用XRD、SEM和EDS对试样的物相组成、微观形貌和微区成分进行分析.结果表明,在1100~1200℃、保温2h,原料反应合成了主相Ti3SiC2,同时含有少量TiC、SiC相;当温度为1300℃时,Ti3SiC2开始明显分解;当温度升至1350℃时,试样中Ti3SiC2完全分解,产物主要由TiC相和少量SiC组成;六方TiC晶粒边长5μm.

  10. Comparison Study on the Microstructure of Nanocrystalline TiO2 in Different Ti-Si Binary Oxides

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Three different Ti-Si oxide structuares, silica supported titania, silica coated titania and intimately mixed silicatitania, containing 10%-40% SiO2, were made by sol-gel process. The variations of microstructure parameters of nanocrystalline (nc) TiO2-anatase in the three kirds of binary oxides, including in-plane spacing d, cell constants (a0, CQ), cell volume V, cell axial ratio c0/a0 and crystal grain size, were comparatively investigated by high resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD). It is found that the microstructure parameters vary remarkably with increasing SiO2 content and annealing temperature. Different structured Ti-Si binary oxides lead to different variation tendencies of microstructure parameters. The more SiO2 the binary oxide contains, the more lattice defects of nc TiO2-anatase appear; diffusion or migration of Si cations could be an important influential factor in the variations of microstructure. The grain size of nc TiO2 in the three kinds of binary oxides not only depends on SiO2 content and annealing temperature but also on the degree of lattice microstrain and distortion of nc TiO2-anatase. Both grain size and phase transformation of nc TiO2-anatase are effectively inhibited with increasing SiOa content.

  11. Elastic and thermo-physical properties of TiC, TiN, and their intermediate composition alloys using ab initio calculations

    International Nuclear Information System (INIS)

    Kim, Jiwoong; Kang, Shinhoo

    2012-01-01

    Highlights: ► Elastic properties of TiC, TiN and their alloys were calculated by ab initio calculations. ► Debye temperature and Gruneisen constant of TiC, TiN and their alloys were calculated as a function of nitrogen content. ► Thermo-physical properties were calculated as a function of nitrogen content. ► Thermal expansion of the alloys was fitted in different temperature range. - Abstract: The equilibrium lattice parameters, elastic properties, material brittleness, heat capacities, and thermal expansion coefficients of TiC, TiN, and their intermediate composition alloys (Ti(C 1−x N x ), x = 0.25, 0.5, and 0.75) were calculated using ab initio density functional theory (DFT) methods. We employed the Debye–Gruneisen model to calculate a finite temperature heat capacity and thermal expansion coefficient. The calculated elastic moduli and thermal expansion coefficients agreed well with the experimental data and with other DFT calculations. Accurate heat capacities of TiC, TiN, and their intermediate composition alloys were obtained by calculating not only the phonon contributions but also the electron contributions to the heat capacity. Our calculations indicated that the heat capacity differences between each composition originated mainly from the electronic contributions.

  12. XPS Spectra Analysis of Ti2+, Ti3+ Ions and Dye Photodegradation Evaluation of Titania-Silica Mixed Oxide Nanoparticles

    Science.gov (United States)

    Chinh, Vu Duc; Broggi, Alessandra; Di Palma, Luca; Scarsella, Marco; Speranza, Giorgio; Vilardi, Giorgio; Thang, Pham Nam

    2018-04-01

    TiO2-SiO2 mixed oxides have been prepared by the sol-gel technique from tetrabutyl orthotitanate and tetraethyl orthosilicate. The prepared materials were characterized by x-ray diffraction, scanning electron microscopy, energy dispersive x-ray spectroscopy, nitrogen physisorption, Fourier-transform infrared spectroscopy (FT-IR) and x-ray photoelectron spectroscopy (XPS). The results indicate that the TiO2-SiO2 mixed oxides have a large surface area and a nanoscale size. FT-IR spectra show that Ti atoms are bonded to silica by oxygen bridging atoms in Ti-O-Si bonds. The titanium valence states in TiO2-SiO2 mixed oxides were investigated by XPS, and their spectra report the presence of Ti2+ and Ti3+ cations for high silica concentration, suggesting the formation of oxygen vacancies. The photocatalytic activity of the prepared materials has been evaluated for the photodegradation of methylene blue (MB). The mixed oxides were activated by means of a UV light source, and the concentration of MB was monitored by UV-Vis spectroscopy. The synthesized TiO2-SiO2 shows significantly higher MB removal efficiency in comparison with that of the commercial TiO2 Degussa, P25.

  13. 1020 steel coated with Ti/TiN by Cathodic Arc and Ion Implantation

    International Nuclear Information System (INIS)

    Bermeo, F; Quintana, J P; Kleiman, A; Márquez, A; Sequeda, F

    2017-01-01

    TiN coatings have been widely studied in order to improve mechanical properties of steels. In this work, thin Ti/TiN films were prepared by plasma based immersion ion implantation and deposition (PBII and D) with a cathodic arc on AISI 1020 steel substrates. Substrates were exposed to the discharge during 1 min in vacuum for the deposition of a Tiunderlayer with the aim of improving the adhesion to the substrate. Then, a TiN layer was deposited during 6 min in a nitrogen environment at a pressure of 3xl0 -4 mbar. Samples were obtained at room temperature and at 300 °C, and with or without ion implantation in order to analyze differences between the effects of each treatment on the tribological properties. The mechanical and tribological properties of the films were characterized. The coatings deposited by PBII and D at 300 °C presented the highest hardness and young modulus, the best wear resistance and corrosion performance. (paper)

  14. Influence of TiB2 particles on machinability and machining parameter optimization of TiB2/Al MMCs

    Directory of Open Access Journals (Sweden)

    Ruisong JIANG

    2018-01-01

    Full Text Available In situ formed TiB2 particle reinforced aluminum matrix composites (TiB2/Al MMCs have some extraordinary properties which make them be a promising material for high performance aero-engine blade. Due to the influence of TiB2 particles, the machinability is still a problem which restricts the application of TiB2/Al MMCs. In order to meet the industrial requirements, the influence of TiB2 particles on the machinability of TiB2/Al MMCs was investigated experimentally. Moreover, the optimal machining conditions for this kind of MMCs were investigated in this study. The major conclusions are: (1 the machining force of TiB2/Al MMCs is bigger than that of non-reinforced alloy and mainly controlled by feed rate; (2 the residual stress of TiB2/Al MMCs is compressive while that of non-reinforced alloy is nearly neutral; (3 the surface roughness of TiB2/Al MMCs is smaller than that of non-reinforced alloy under the same cutting speed, but reverse result was observed when the feed rate increased; (4 a multi-objective optimization model for surface roughness and material removal rate (MRR was established, and a set of optimal parameter combinations of the machining was obtained. The results show a great difference from SiC particle reinforced MMCs and provide a useful guide for a better control of machining process of this material.

  15. Electrochemical behavior of Ti and Ti6Al4V in aqueous solutions of citric acid containing halides

    Directory of Open Access Journals (Sweden)

    Anelise Marlene Schmidt

    2006-12-01

    Full Text Available This paper reports on an investigation of the electrochemical behavior of Ti grade 2 and Ti6Al4V alloy in aqueous citric acid solutions with pH 2.0 containing halide ions. Voltammetric studies of Ti and the alloy in citric acid, with and without chloride ions, indicate that the Ti and Ti alloy presented a passive behavior in the test solutions used. Pitting was observed at 3.0 and 2.5 V/SCE for Ti and Ti6Al4V, respectively, when bromide ions were added to the solution. In solutions containing fluoride ions, dissolution of the film occurred at potentials close to - 1.0 V/SCE in both electrodes. The iodide ions oxidized on the passive oxide film at potentials close to 1.0 V/SCE. EIS results of the materials in citric acid solutions containing chloride ions revealed that the film's resistance increased as the applied potential rose from 0 to 1.0 V. In bromide-containing solutions, breakdown of the film was confirmed at potentials above 2.0 V/SCE in both electrodes. These results suggest film reformation for Ti and the alloy in solutions containing fluoride at potentials within the passive region.

  16. Orientation of Al3Ti platelets in Al-Al3Ti functionally graded material manufactured by centrifugal method

    International Nuclear Information System (INIS)

    Watanabe, Y.; Fukui, Y.

    1997-01-01

    Al-Al 3 Ti functionally graded materials (FGMs) were manufactured by the centrifugal method with a commercial ingot of Al-5 mass% Ti master alloy. The alloy was melted at a liquid/solid coexisting temperature, at which Al 3 Ti remains as a solid, and then it was cast into a thick-walled ring. It was found that the Al-Al 3 Ti functionally graded material can be successfully fabricated by the centrifugal method. It was also found that the volume fraction of the Al 3 Ti can be increased by repetition of the centrifugal method. Since the shape of Al 3 Ti particles in a commercial alloy ingot is that of a platelet, the Al 3 Ti particles are arranged with their platelet planes nearly perpendicular to the radial direction. The orientation effects become stronger when the G number becomes larger. Although the final centrifugal casting was conducted under a very large centrifugal force for the specimen cast three times, the orientation effects were weaker than those in the specimen cast one time. From these observations, it is concluded that the origin of orientation of Al 3 Ti platelets can be attributed to the angular velocity gradient of the melt along the radial direction produced by the difference in the viscosity. (orig.)

  17. The Atomic Structure of Ti2C and Ti3C2 MXenes is Responsible for Their Antibacterial Activity Toward E. coli Bacteria

    Science.gov (United States)

    Jastrzębska, Agnieszka Maria; Karwowska, Ewa; Wojciechowski, Tomasz; Ziemkowska, Wanda; Rozmysłowska, Anita; Chlubny, Leszek; Olszyna, Andrzej

    2018-02-01

    The expanded Ti2C and Ti3C2 MXene phases were synthesized from their parent Ti2AlC and Ti3AlC2 MAX phases using the same conditions of the classical acidic aluminum extraction method. The assumption for the study was that the expanded Ti2C and Ti3C2 MXenes are composed of the same atoms and if are synthesized from MAX phases using the same conditions of the classical acidic aluminum extraction method, the observed bio-effects can be related only to the changes in their structures. The scanning electron microscope investigations indicated that the expanded Ti2C and Ti3C2 sheets formed the specific network of slit-shaped nano-pores. The x-ray photoelectron spectroscopy for chemical analysis (ESCA-XPS) showed almost no difference in surface chemistry of Ti2C and Ti3C2 MXenes. The high-resolution transmission electron microscope investigations revealed, however, differences in atomic structure of the individual Ti2C and Ti3C2 sheets. Measured distance between Ti-C atomic layers in Ti2C was 9.76 Å and was larger by 0.53 Å in comparison with Ti3C2 (9.23 Å). Our investigations of bioactive properties toward model gram-negative Escherichia coli bacterial strain showed that the Ti2C MXene did not influence the viability of bacteria. Contrarily, the Ti3C2 MXene showed antibacterial properties. The results of the study indicate that the structure at the atomic scale may play a key role in the bioactivity of MXenes of the same chemical composition, but different stoichiometry, just like in case of Ti2C and Ti3C2.

  18. NiTi intermetallic surface coatings by laser metal deposition for improving wear properties of Ti-6Al-4V substrates

    CSIR Research Space (South Africa)

    Mokgalaka, MN

    2014-03-01

    Full Text Available The NiTi intermetallic possesses a number of good properties, such as high wear, oxidation, and corrosion resistance. This paper focuses on the deposition of NiTi intermetallic coatings on Ti6Al4V substrate by laser melting of Ti and Ni elemental...

  19. The mechanical and electronic properties of Al/TiC interfaces alloyed by Mg, Zn, Cu, Fe and Ti: First-principles study

    International Nuclear Information System (INIS)

    Sun, Ting; Wu, Xiaozhi; Wang, Rui; Li, Weiguo

    2015-01-01

    The adhesion and ductility of (100) and (110) Al/TiC interfaces alloyed by Mg, Zn, Cu, Fe, and Ti have been investigated using first-principles methods. Fe and Ti can enhance the adhesion of (100) and (110) interfaces. Mg and Zn have the opposite effect. Interfacial electronic structures have been created to analyze the changes of the work of adhesion. It is found that more charge is accumulated at interfaces alloyed by Fe and Ti compared with pure Al/TiC. There is also an obvious downward shift in the Fermi energy of Fe, Ti at the interface. Furthermore, the unstable stacking fault energies of the interfaces are calculated; the results demonstrate that the preferred slip direction is the 〈110〉 direction for (100) and (110) Al/TiC. Based on the Rice criterion of ductility, the results predict that Mg, Fe, and Ti are promising candidates for improving the ductility of Al/TiC interfaces. (paper)

  20. The influence of Ti doping and annealing on Ce{sub 2}Ti{sub 2}O{sub 7} flash memory devices

    Energy Technology Data Exchange (ETDEWEB)

    Kao, Chyuan Haur [Department of Electronic Engineering, Chang Gung University, No. 259, Wenhua 1st Rd., Guishan Dist., Taoyuan City 33302, Taiwan, ROC (China); Kidney Research Center, Department of Nephrology, Chang Gung Memorial Hospital, Chang Gung University, College of Medicine, Taoyuan, Taiwan, ROC (China); Department of Electronic Engineering, Ming Chi University of Technology, Taiwan, ROC (China); Chen, Su Zhien [Department of Electronic Engineering, Chang Gung University, No. 259, Wenhua 1st Rd., Guishan Dist., Taoyuan City 33302, Taiwan, ROC (China); Kidney Research Center, Department of Nephrology, Chang Gung Memorial Hospital, Chang Gung University, College of Medicine, Taoyuan, Taiwan, ROC (China); Luo, Yang; Chiu, Wang Ting; Chiu, Shih Wei; Chen, I Chien [Department of Applied Materials and Optoelectronic Engineering, National Chi Nan University, No. 1, University Rd., Puli, Nantou Country 54561, Taiwan, ROC (China); Lin, Chan-Yu [Kidney Research Center, Department of Nephrology, Chang Gung Memorial Hospital, Chang Gung University, College of Medicine, Taoyuan, Taiwan, ROC (China); Chen, Hsiang, E-mail: hchen@ncnu.edu.tw [Department of Applied Materials and Optoelectronic Engineering, National Chi Nan University, No. 1, University Rd., Puli, Nantou Country 54561, Taiwan, ROC (China)

    2017-02-28

    Highlights: • Ce{sub 2}Ti{sub 2}O{sub 7} flash memories have been fabricated. • Material quality can be improved by annealing. • The memory performance can be enhanced by Ti doping. • Ti doping and annealing can reinforce crystallization. - Abstract: In this research, a CeO{sub 2} film with Ti doping was used as a trapping layer in metal oxide high-K-oxide-Si (MOHOS)-type memory devices. Since incorporation of Ti atoms into the film could fix dangling bonds and defects, the Ce{sub 2}Ti{sub 2}O{sub 7} trapping layer with annealing treatment could have a larger memory window and a faster programming/erasing speed. To confirm the origin, multiple material analyses indicate that annealing at an appropriate temperature and Ti doping could enhance crystallization. The Ce{sub 2}Ti{sub 2}O{sub 7}-based memory device is promising for future industrial flash memory applications.

  1. Solid-state synthesis of Li_4Ti_5O_1_2 whiskers from TiO_2-B

    International Nuclear Information System (INIS)

    Yao, Wenjun; Zhuang, Wei; Ji, Xiaoyan; Chen, Jingjing; Lu, Xiaohua; Wang, Changsong

    2016-01-01

    Highlights: • The Li_4Ti_5O_1_2 whiskers were synthesized from TiO_2-B whiskers via a solid state reaction. • The TiO_2-B crystal structure for lithium diffusion is easier than anatase. • The separated diffusion and reaction process is crucial for the solid-state syntheses of Li_4Ti_5O_1_2 whiskers. - Abstract: In this work, Li_4Ti_5O_1_2 (LTO) was synthesized from the precursors of TiO_2-B and anatase whiskers, respectively. The synthesized LTO whiskers from TiO_2-B whiskers via a solid state reaction at 650 °C have a high degree of crystallinity with an average diameter of 300 nm. However, when anatase whiskers were used as the precursor, only particle morphology LTO was produced at 750 °C. The further analysis of the precursors, the intermediate products and the final products reveal that the crystal structure of the anatase hinders the diffusion of lithium, leading to a typical reaction–diffusion process. Under this condition, only particle morphology LTO can be produced. However, the crystal structure of the TiO_2-B is easy for lithium diffusion and the process is performed in two separated steps (i.e., diffusion and reaction), which makes it possible to decrease the solid-state reaction temperature down to 650 °C and then maintain the morphologies of whiskers.

  2. Effect of graphite content on magnetic and mechanical properties of TiC-TiN-Mo-Ni cermets

    Science.gov (United States)

    Zhang, Man; Yang, Qingqing; Xiong, Weihao; Huang, Bin; Ruan, Linji; Mao, Qiao; Li, Shengtao

    2018-04-01

    TiC-10TiN-6Mo-xGr-yNi (mol%, Gr represents graphite, x = 0, 2, 4, 6, 8, and y = 15, 30) cermets were prepared by powder metallurgy method, in order to inverstigate the effect of Gr content on magnetic and mechanical properties of TiC-TiN-Mo-Ni cermets. Room-temperature (RT) saturation magnetization (Ms) and remanence (Mr) of cermets increased with increasing x. This was mainly attributed to that the total content of non-ferromagnetic carbonitride-forming elements Ti and Mo in Ni-based binder phase decreased with increasing x. At the same x, cermets for y = 15 had lower RT Ms and Mr than those for y = 30. Cermets containing more than 2 mol% Gr became ferromagnetic at RT. Bending strength of cermets first increased and then decreased with increasing x. It reached the maximum at x = 2, mainly due to high total content of solutes Ti and Mo in Ni-based binder phase, and moderate thickness of outer rim of Ti(C,N) ceramic grains. Hardness of cermets was not significantly affected by x, mainly due to the combined action of the decrease of the total content of Ti and Mo in binder phase and the increase of the volume fraction of ceramic grains. At the same x, cermets for y = 15 had lower bending strength and higher hardness than those for y = 30.

  3. TiC reinforced cast Cr steels

    Energy Technology Data Exchange (ETDEWEB)

    Dogan, O.N.; Hawk, J.A.; Schrems, K.K.

    2006-06-01

    A new class of materials, namely TiC-reinforced cast chromium (Cr) steels, was developed for applications requiring high abrasion resistance and good fracture toughness. The research approach was to modify the carbide structure of commercial AISI 440C steel for better fracture resistance while maintaining the already high abrasion resistance. The new alloys contained 12Cr, 2.5–4.5Ti, and 1–1.5C (wt.%) and were melted in a vacuum induction furnace. Their microstructure was composed primarily of a martensitic matrix with a dispersion of TiC precipitates. Modification of TiC morphology was accomplished through changing the cooling rate during solidification. Wear rates of the TiC-reinforced Cr steels were comparable to that of AISI 440C steel, but the impact resistance was much improved.

  4. TiC-reinforced cast Cr steels

    Science.gov (United States)

    Doğan, Ö. N.; Hawk, J. A.; Schrems, K. K.

    2006-06-01

    A new class of materials, namely TiC-reinforced cast chromium (Cr) steels, was developed for applications requiring high abrasion resistance and good fracture toughness. The research approach was to modify the carbide structure of commercial AISI 440C steel for better fracture resistance while maintaining the already high abrasion resistance. The new alloys contained 12Cr, 2.5-4.5Ti, and 1-1.5C (wt.%) and were melted in a vacuum induction furnace. Their microstructure was composed primarily of a martensitic matrix with a dispersion of TiC precipitates. Modification of TiC morphology was accomplished through changing the cooling rate during solidification. Wear rates of the TiC-reinforced Cr steels were comparable to that of AISI 440C steel, but the impact resistance was much improved.

  5. Influence of TiCl4 post-treatment condition on TiO2 electrode for enhancement photovoltaic efficiency of dye-sensitized solar cells.

    Science.gov (United States)

    Eom, Tae Sung; Kim, Kyung Hwan; Bark, Chung Wung; Choi, Hyung Wook

    2014-10-01

    Titanium tetrachloride (TiCl4) treatment processed by chemical bath deposition is usually adopted as pre- and post-treatment for nanocrystalline titanium dioxide (TiO2) film deposition in the dye-sensitized solar cells (DSSCs) technology. TiCl4 post-treatment is a widely known method capable of improving the performance of dye-sensitized solar cells. In this work, the effect of TiCl4 post-treatment on the TiO2 electrode is proposed and compared to the untreated film. A TiO2 passivating layer was deposited on FTO glass by RF magnetron sputtering. The TiO2 sol prepared sol-gel method, nanoporous TiO2 upper layer was deposited by screen printing method on the passivating layer. TiCl4 post-treatment was deposited on the substrate by hydrolysis of TiCl4 aqueous solution. Crystalline structure was adjusted by various TiCl4 concentration and dipping time: 20 mM-150 mM and 30 min-120 min. The conversion efficiency was measured by solar simulator (100 mW/cm2). The dye-sensitized solar cell using TiCl4 post-treatment was measured the maximum conversion efficiency of 5.04% due to electron transport effectively. As a result, the DSSCs based on TiCl4 post-treatment showed better photovoltaic performance than cells made purely of TiO2 nanoparticles. The relative DSSCs devices are characterized in terms of short circuit current density, open circuit voltage, fill factor, conversion efficiency.

  6. Supramolecular photocatalyst of RGO-cyclodextrin-TiO2

    International Nuclear Information System (INIS)

    Shen, Jianfeng; Li, Na; Ye, Mingxin

    2013-01-01

    Graphical abstract: Supramolecular photocatalyst of RGO-cyclodextrin-TiO 2 was achieved, which showed high photocatalytic activity and adsorption capacity. Highlights: •Supramolecular photocatalyst of RGO-cyclodextrin-TiO 2 was achieved. •β-CD molecules acted as linkers between RGO and monodisperse TiO 2 nanoparticles. •Reduction of GO and preparation of RGO-cyclodextrin-TiO 2 was simultaneous. •The prepared RGO-cyclodextrin-TiO 2 shows high photocatalytic activity and adsorption capacity. -- Abstract: Reduced graphene oxide (RGO)/β-cyclodextrin (β-CD)/titanium oxide (TiO 2 ) supramolecular photocatalyst was synthesized with a one-pot hydrothermal method. The reducing process was accomplished with the attaching of β-CD and generation of TiO 2 . β-CD acted as a linker between RGO and monodisperse TiO 2 nanoparticles. The structure and composition of the hybrid had been characterized by Fourier transform infrared spectroscopy, Raman spectroscopy, thermal gravimetric analysis, X-ray diffraction and Transmission electron microscopy. The as-prepared RGO-CD-TiO 2 showed significant enhanced performance for phenol and Cr (VI) removal, due to the effective transfer of photo-generated electron from TiO2 to RGO and improved absorbance performance of the hybrid

  7. Fabrication of TiO2 nanorod assembly grafted rGO (rGO@TiO2-NR) hybridized flake-like photocatalyst

    Science.gov (United States)

    Lv, Kangle; Fang, Shun; Si, Lingling; Xia, Yang; Ho, Wingkei; Li, Mei

    2017-01-01

    To efficiently separate the photo-generated electron-hole pairs of TiO2 hybrid, anatase TiO2 nanorod assembly grafted reduced graphene oxides (rGO@TiO2-NR) hybrid was successfully fabricated using potassium titanium oxalate (PTO) and graphene oxides (GO) as starting materials and diethylene glycol (DEG) as reductant. The effect of GO content on the structure and photocatalytic activity of rGO@TiO2-NR composite was systematically studied. Results show that, in the absence of GO, only TiO2 microsphere assembly is obtained from TiO2 nanorods. The presence of GO results in the formation of a flake-like TiO2-nanorod-assembled grafted rGO hybrid. The photocatalytic activity of rGO@TiO2-NR composite increases first and then decreases with increase in the amount of GO from 0 wt.% to 10 wt.%. The hybridized S4 sample prepared with 4 wt.% GO possesses the highest photocatalytic activity with a constant rate of 0.039 min-1 in the photocataytic degradation of Brilliant X-3B dye (X3B); this sample was enhanced more than three times when compared with pure TiO2 sample (0.012 min-1). The enhanced photocatalytic activity of the rGO@TiO2-NR hybrid was attributed to the strong interaction between TiO2 nanorods and rGO. The unique hierarchical structure of 1D nanorod assembly TiO2-rGO flakes facilitates the injection and transfer of photo-generated electrons from TiO2 to graphene, thus retarding the recombination of electron-hole pairs and enhancing the photocatalytic activity. The enlarged BET surface areas, not only increasing the number of active sites, but also facilitating the adsorption of the dye, and improved light-harvesting ability also contribute to the enhanced photoreactivity of rGO@TiO2-NR hybrid.

  8. Photocatalytic self-cleaning cotton fabrics with platinum (IV) chloride modified TiO{sub 2} and N-TiO{sub 2} coatings

    Energy Technology Data Exchange (ETDEWEB)

    Long, Mingce, E-mail: long_mc@sjtu.edu.cn [School of Environmental Science and Engineering, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai, 200240 (China); Key Laboratory for Thin Film and Microfabrication of the Ministry of Education, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai, 200240 (China); Zheng, Longhui; Tan, Beihui [School of Environmental Science and Engineering, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai, 200240 (China); Shu, Heping [Xiaoxi New Materials Science and Technology (Shanghai) Co. Ltd., 655 Cangyuan Road, Shanghai, 200240 (China)

    2016-11-15

    Highlights: • Platinum (IV) chloride modified TiO{sub 2} and N-TiO{sub 2} nanosols are synthesized. • Pt-TiO{sub 2} coatings display enhanced performance in the degradation of MO and stains. • Surface attached PtCl{sub 6}{sup 2−} enable visible light activity of TiO{sub 2} coated cotton fabric. - Abstract: To enable photocatalytic self-cleaning cotton fabrics working under visible light irradiation, platinum (IV) chloride modified TiO{sub 2} (Pt-TiO{sub 2}) and N-TiO{sub 2} (Pt-N-TiO{sub 2}) nanosols are synthesized through a low temperature precipitation-peptization method. According to the characterizations of XRD, DRS and TEM, all nanoparticles are anatase nanocrystallites in the sizes of less than 10 nm, while N-TiO{sub 2} nanoparticles have better crystallization and smaller sizes. However, the cotton fabrics functionalized with Pt-TiO{sub 2} display significantly enhanced photocatalytic activity for methyl orange degradation and coffee stain removal under both solar simulator and visible light irradiation, while the performance of that coatings of Pt-N-TiO{sub 2} is poor. Further XRF and XPS results indicate that surface species on N-TiO{sub 2} block the adsorption of PtCl{sub 6}{sup 2−} anions, whereas these anions strongly attach on the surface of TiO{sub 2} nanoparticles, and accordingly enable functionalized cotton fabrics efficient visible light driven activities based on a mechanism of charge transfer from ligand to metal (CTLM) excitation.

  9. The corrosion and passivity of sputtered Mg–Ti alloys

    International Nuclear Information System (INIS)

    Song, Guang-Ling; Unocic, Kinga A.; Meyer, Harry; Cakmak, Ercan; Brady, Michael P.; Gannon, Paul E.; Himmer, Phil; Andrews, Quinn

    2016-01-01

    Highlights: • A supersaturated single phase Mg–Ti alloy can be obtained by magnetron sputtering. • The anodic dissolution of Mg–Ti alloy is inhibited by Ti addition. • The alloy becomes passive when Ti content is high and the alloy has become Ti based. • The formation of a continuous thin passive film is responsible for the passivation of the alloy. - Abstract: This study explored the possibility of forming a “stainless” Mg–Ti alloy. The electrochemical behavior of magnetron-sputtered Mg–Ti alloys was measured in a NaCl solution, and the surface films on the alloys were examined by XPS, SEM and TEM. Increased corrosion resistance was observed with increased Ti content in the sputtered Mg–Ti alloys, but passive-like behavior was not reached until the Ti level (atomic %) was higher than the Mg level. The surface film that formed on sputtered Mg–Ti based alloys in NaCl solution was thick, discontinuous and non-protective, whereas a thin, continuous and protective Mg and Ti oxide film was formed on a sputtered Ti–Mg based alloy.

  10. Preparation, characterization and applications of novel carbon and nitrogen codoped TiO2 nanoparticles from annealing TiN under CO atmosphere

    International Nuclear Information System (INIS)

    Sun, Mingxuan; Song, Peng; Li, Jing; Cui, Xiaoli

    2013-01-01

    Graphical abstract: Carbon and nitrogen codoped TiO 2 nanoparticles were firstly fabricated by calcining TiN powder under CO atmosphere at different temperatures between 400 and 600 °C, both the improved photocatalytic activity for degradation of methylene blue and enhanced photovoltaic performance for dye sensitized solar cells were demonstrated. - Highlights: • CN-codoped TiO 2 nanoparticles were prepared by calcining TiN under CO atmosphere. • More visible light response was confirmed by UV–vis DRS and photocatalytic results. • Enhanced conversion efficiency was observed for the DSSCs from CN-TiO 2 photoanode. • CN-codoping played an important role to improve the photocatalytic performance. - Abstract: Carbon and nitrogen codoped titania (CN-TiO 2 ) nanoparticles were fabricated by calcining titanium nitride (TiN) nanoparticles under carbon monoxide (CO) atmosphere at four different temperatures in a range of 400–600 °C. The as-prepared samples were characterized with X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM) and X-ray photoelectron spectroscopy (XPS). Enhanced light absorption in both the UV and visible light region was observed for the resulted CN-TiO 2 nanoparticles in ultraviolet-visible diffuse reflectance spectroscopy (UV–vis DRS). Improved photocatalytic activity toward the degradation of methylene blue by the CN-TiO 2 nanoparticles was demonstrated under UV and visible light, respectively. The highest degradation rate was achieved for CN-TiO 2 nanoparticles (13%) compared to N-TiO 2 (10%) and the commercial P25 (5%) under visible light illumination for 40 min. Furthermore, the improved photocatalytic activity of CN-TiO 2 was also confirmed by the degradation of colorless resorcinol under UV–vis light irradiation. Dye-sensitized solar cells (DSSCs) were fabricated using P25, N-TiO 2 and CN-TiO 2 photoanodes, respectively. The highest conversion efficiency of 3.31% was achieved by the DSSCs based on the

  11. The kinetics of formation and growth of TiC precipitates in Ti-modified stainless steel studied by positron annihilation spectroscopy

    International Nuclear Information System (INIS)

    Gopalan, P.; Rajaraman, R.; Viswanathan, B.; Venkadesan, S.

    1998-01-01

    The formation and growth of TiC precipitates in Ti-modified austenitic stainless steel (D-9 alloy) is monitored by positron lifetime spectroscopy. From isochronal annealing studies various recovery stages are identified. TiC precipitates are found to be more stable in 20% cold worked alloy than in a 17.5% cold worked sample. From the isothermal annealing studies, it is found that TiC precipitation is controlled by dislocations. The limited temperature dependence of dislocation controlled TiC precipitation is governed by an apparent activation energy of 1.6 eV. In 20% cold worked alloy, TiC precipitates are found to be stable against growth even after 1000 h of annealing at 923 K. For higher annealing temperatures, TiC precipitate coarsening occurs due to recrystallisation. (orig.)

  12. Confining jackets for concrete cylinders using NiTiNb and NiTi shape memory alloy wires

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Eunsoo; Yoon, Soon-Jong [Department of Civil Engineering, Hongik University, Seoul 121-791 (Korea, Republic of); Nam, Tae-Hyun [School of Materials Science and Engineering and ERI, Gyeongsang National University, Jinju, Gyeongnam 600-701 (Korea, Republic of); Cho, Sun-Kyu [School of Civil Engineering, Seoul National University of Technology, Seoul 139-743 (Korea, Republic of); Park, Joonam, E-mail: eunsoochoi@hongik.ac.k [Department of Railroad Structure Research, Korea Railroad Research Institute, Uiwang 437-050, Korea (Korea, Republic of)

    2010-05-01

    This study used prestrained NiTiNb and NiTi shape memory alloy (SMA) wires to confine concrete cylinders. The recovery stress of the wires was measured with respect to the maximal prestrain of the wires. SMA wires were preelongated during the manufacturing process and then wrapped around concrete cylinders of 150 mmx300 mm ({phi}xL). Unconfined concrete cylinders were tested for compressive strength and the results were compared to those of cylinders confined by SMA wires. NiTiNb SMA wires increased the compressive strength and ductility of the cylinders due to the confining effect. NiTiNb wires were found to be more effective in increasing the peak strength of the cylinders and dissipating energy than NiTi wires. This study showed the potential of the proposed method to retrofit reinforced concrete columns using SMA wires to protect them from earthquakes.

  13. Preparation of hydrogenated-TiO2/Ti double layered thin films by water vapor plasma treatment

    International Nuclear Information System (INIS)

    Pranevicius, L.L.; Milcius, D.; Tuckute, S.; Gedvilas, K.

    2012-01-01

    Highlights: ► We investigated reaction of water plasma with nanocrystalline TiO 2 films. ► Simultaneous oxidation and hydrogenation of Ti was observed during plasma treatment. ► Water plasma treatment forms hydrogenated nanocrystalline TiO 2 in the shallow surface. - Abstract: We have investigated the structural and compositional variations in 200–500 nm thick Ti films deposited by magnetron sputter-deposition technique and treated in water vapor plasma at different processing powers. It was found that the upper layer of treated film with the thickness of 110 nm was changed into the black hydrogenated-TiO 2 with around 16 nm sized nanocystals during 10 min for dissipated power 200 W at room temperature. Analysis of the experimental results is used to obtain insights into the effects of water layer adsorbed on hydrophilic oxidized titanium surfaces exposed to plasma radiation.

  14. Hydrogen isotope behavior on Li2TiO3

    International Nuclear Information System (INIS)

    Olivares, Ryan; Oda, Takuji; Tanaka, Satoru; Oya, Yasuhisa; Tsuchiya, Kunihiko

    2004-01-01

    The surface nature of Li 2 TiO 3 and the adsorption behavior of water on Li 2 TiO 3 surface were studied by XPS/UPS and FT/IR. Preliminary experiments by Ar ion sputtering, heating and water exposure were conducted, and the following results were obtained. (1) By Ar sputtering, Li deficient surface was made, and Ti was reduced from Ti 4+ to Ti 3+ . (2) By heating sputtered samples over 573-673 K, Li emerged on the surface and Ti was re-oxidized to Ti 4+ . The surface -OH was removed. The valence band of Li 2 TiO 3 became similar to that of TiO 2 . (3) By water exposure at 623 K, H 2 O could be adsorbed dissociatively on the surface. LiOH was not formed. (4) The nature of Li 2 TiO 3 surface resembles that of TiO 2 , rather than Li 2 O. (author)

  15. Sol-gel synthesis of TiO2 nanoparticles and photocatalytic degradation of methyl orange in aqueous TiO2 suspensions

    International Nuclear Information System (INIS)

    Yang Huaming; Zhang Ke; Shi Rongrong; Li Xianwei; Dong Xiaodan; Yu Yongmei

    2006-01-01

    Anatase TiO 2 nanoparticles of about 16 nm in crystal size have been successfully synthesized via a sol-gel method. Thermal treatment of the precursor at 500-600 deg. C results in the formation of different TiO 2 phase compositions. The samples were characterized by means of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). Effects of the pH value of the solution, H 2 O 2 addition, TiO 2 phase composition and recycled TiO 2 on the photocatalytic degradation of methyl orange (MeO) in TiO 2 suspensions under ultraviolet (UV) illumination were primarily investigated. The results indicate that a low pH value, proper amount of H 2 O 2 and pure anatase TiO 2 will facilitate the photocatalytic oxidation of the MeO solution. The photodegradation degree decreases with increasing the pH value of the solution and varies with different amounts of H 2 O 2 . Pure anatase TiO 2 shows better photocatalytic activity for MeO decolorization than biphase TiO 2 . The photocatalytic mechanism of the as-synthesized TiO 2 nanoparticles was discussed

  16. Ti-84 Plus graphing calculator for dummies

    CERN Document Server

    McCalla

    2013-01-01

    Get up-to-speed on the functionality of your TI-84 Plus calculator Completely revised to cover the latest updates to the TI-84 Plus calculators, this bestselling guide will help you become the most savvy TI-84 Plus user in the classroom! Exploring the standard device, the updated device with USB plug and upgraded memory (the TI-84 Plus Silver Edition), and the upcoming color screen device, this book provides you with clear, understandable coverage of the TI-84's updated operating system. Details the new apps that are available for download to the calculator via the USB cabl

  17. Complementary and bipolar regimes of resistive switching in TiN/HfO{sub 2}/TiN stacks grown by atomic-layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Egorov, K.V.; Kirtaev, R.V.; Markeev, A.M.; Zablotskiy, A.V. [Moscow Institute of Physics and Technology, Institutskii per. 9, 141700, Dolgoprudny (Russian Federation); Lebedinskii, Yu.Yu.; Matveyev, Yu.A.; Zenkevich, A.V. [Moscow Institute of Physics and Technology, Institutskii per. 9, 141700, Dolgoprudny (Russian Federation); National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Kashirskoye shosse 31, 115409, Moscow (Russian Federation); Orlov, O.M. [Scientific Research Institute of Molecular Electronics and Plant ' ' Micron' ' , 124462, Zelenograd (Russian Federation)

    2015-04-01

    Atomic-layer deposition (ALD) technique in combination with in vacuo X-ray photoelectron spectroscopy (XPS) analysis has been successfully employed to obtain fully ALD-grown planar TiN/HfO{sub 2}/TiN metal-insulator-metal structures for resistive random access memory (ReRAM) memory elements. In vacuo XPS analysis of ALD-grown TiN/HfO{sub 2}/TiN stacks reveals the presence of the ultrathin oxidized layers consisting of TiON (∝0.5 nm) and TiO{sub 2} (∝0.6 nm) at the bottom TiN/HfO{sub 2} interface (i); the nonoxidized TiN at the top HfO{sub 2}/TiN interface (ii); the oxygen deficiency in the HfO{sub 2} layer does not exceed the XPS detection limit (iii). Electroformed ALD TiN/HfO{sub 2}/TiN stacks reveal both conventional bipolar and complementary types of resistive switching. In the complementary resistive switching regime, each programming sequence is terminated by a reset operation, leaving the TiN/HfO{sub 2}/TiN stack in a high-resistance state. The observed feature can avoid detrimental leaky paths during successive reading operation, which is useful in the passive ReRAM arrays without a selector element. The bipolar regime of resistive switching is found to reveal the gradual character of the SET and RESET switching processes. Long-term potentiation and depression tests performed on ALD-grown TiN/HfO{sub 2}/TiN stacks indicate that they can be used as electronic synapse devices for the implementation of emerging neuromorphic computation systems. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  18. First-principles calculations of Ti{sub 3}SiC{sub 2} and Ti{sub 3}AlC{sub 2} with hydrogen interstitial

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Canhui [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang, 621900 (China); Zhang, Haibin, E-mail: hbzhang@caep.cn [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang, 621900 (China); Hu, Shuanglin; Zhou, Xiaosong; Peng, Shuming [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang, 621900 (China); Xiao, Haiyan [School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu, 610054 (China); Zhang, Guojun [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Research Institute of Functional Materials, Donghua University, Shanghai, 201620 (China)

    2017-05-15

    In this paper, the effects of hydrogen interstitial defect on the structural stability of two kinds of MAX materials (Ti{sub 3}SiC{sub 2} and Ti{sub 3}AlC{sub 2}) were investigated by first-principles calculations. The results indicated that the hydrogen interstitial energetically prefers to reside at the 2Ti3Si site for Ti{sub 3}SiC{sub 2} and 3TiAl site for Ti{sub 3}AlC{sub 2}, respectively, and the latter has much lower formation energy. Both of these MAX phases are slightly hardened and the elastic anisotropy is reduced appreciably after the introduction of hydrogen interstitial. The hydrogen interstitial in Ti{sub 3}SiC{sub 2} and Ti{sub 3}AlC{sub 2} leads to an electronic localization effect on the Si/Al atom and the effect is more remarkable in Ti{sub 3}AlC{sub 2}. The interlayer bonding strength of Ti{sub 3}AlC{sub 2} is more weakened by hydrogen interstitials than that of Ti{sub 3}SiC{sub 2}. As a result, the interatomic bonding between Si/Al and Ti atom layers is deteriorated and their structural stabilities degrade subsequently.

  19. A graded nano-TiN coating on biomedical Ti alloy: Low friction coefficient, good bonding and biocompatibility

    Energy Technology Data Exchange (ETDEWEB)

    Cui, Wenfang [Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), School of Material Science and Engineering, Northeastern University, Shenyang 110819 (China); Qin, Gaowu, E-mail: qingw@smm.neu.edu.cn [Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), School of Material Science and Engineering, Northeastern University, Shenyang 110819 (China); Duan, Jingzhu; Wang, Huan [Spinal surgery, Shengjing Hospital, China Medical University, Shenyang 110004 (China)

    2017-02-01

    In order to solve wear resistance of Ti alloy biomaterials, the concept of a graded nano-TiN coating has been proposed. The coating was prepared on Ti-6Al-4V bio-alloy by DC reactive magnetron sputtering. The wear performance of the coated specimens was measured in Hank's solution under the load of 10 N, and the biocompatibility was evaluated according to ISO-10993-4 standard. The results show that the gradient coating exhibits a gradual change in compositions and microstructures along the direction of film growth. Nano-TiN with the size of several to dozens nanometers and Ti{sub 4}N{sub 3−x} transitional phase with variable composition form a graded composite structure, which significantly improves adhesion strength (L{sub c1} = 80 N, L{sub c2} = 120 N), hardness (21 GPa) and anti-wear performance (6.2 × 10{sup −7} mm{sup 3}/Nm). The excellent bonding and wear resistance result from a good match of mechanical properties at substrate/coating interface and the strengthening and toughening effects of the nanocrystalline composite. The nano-TiN coating has also been proved to have good biocompatibility through in-vitro cytotoxicity, hemocompatibility and general toxicity tests. And thus, the proposed graded nano-TiN coating is a good candidate improving wear resistance of many implant medical devices. - Highlights: • A graded nano-TiN coating was prepared on biomedical Ti alloy by PVD. • The combination of hard and soft phase increases hardness and toughness. • The coating exhibits high bonding, low coefficient of friction and wear rate. • The new coating has good bio-safety and great clinical application prospect.

  20. The Microwave-Assisted Green Synthesis of TiC Powders.

    Science.gov (United States)

    Wang, Hui; Zhu, Wencheng; Liu, Yanchun; Zeng, Lingke; Sun, Luyi

    2016-11-08

    Titanium carbide (TiC) is an important engineering material and has found widespread applications. Currently, TiC is typically synthesized through carbothermal reduction, requiring a high temperature (ca. 1700-2300 °C) and long reaction time (ca. 10-20 h), which is not eco-friendly. During a conventional reaction path, anatase TiO₂ (A-TiO₂) was first converted to rutile TiO₂ (R-TiO₂), which was subsequently reduced to TiC. Herein, we explored the synthesis of TiC powders with the assistance of microwave heating. In particular, we achieved the conversion of A-TiO₂, which was more reactive than R-TiO₂ for the carbothermal reduction, to TiC, which was directly due to quick microwave heating. As such, the carbothermal reduction started at a much lower temperature of ca. 1200 °C and finished within 30 min when reacting at 1400 °C, leading to significant energy saving. This study shows that microwave-assisted synthesis can be an effective and green process for preparing TiC powders, which is promising for future large-scale production. The influence of the reaction temperature, the reaction duration, and the carbon content on the synthesis of TiC powders was investigated.

  1. Microstructure and mechanical properties of ion-beam-produced Fe-Ti-(N), Fe-Ti-(C), and Fe-Ti-(C,N) surface films

    Science.gov (United States)

    Hirvonen, J.-P.; Nastasi, M.; Zocco, T. G.; Jervis, T. R.

    1990-06-01

    Ion-mixed films of Fe53 Ti47 were produced by ion irradiating a Fe-Ti multilayer structure on AISI 304 stainless steel. The ion-mixed films were subsequently implanted with nitrogen, carbon, or both carbon and nitrogen. The microstructure following nitrogen implantation consisted of a bcc solid solution of iron and titanium and finely dispersed TiN precipitates. In the cases of carbon or carbon and nitrogen implantation, a two-phase structure consisting of an amorphous matrix with TiC or Ti(C,N) precipitates was found. All these films initially possessed improved tribological properties as revealed by lowered friction and increased wear resistance. However, after an extended test of 1000 wear cycles, a reduced friction was only observed for the carbon or carbon and nitrogen implanted samples. The wear track on the dual implanted surface was extremely smooth, while the surface of the nitrogen-implanted sample was partly worn through, causing the friction to increase to the level of the untreated sample. The improved tribological properties of the implanted films are attributed to an increase in surface hardness. However, the surface hardness is unable to explain differences between different implantations. In the case of the dual carbon and nitrogen implantation, improvements appear to be in part the result from an increased capability to accommodate plastic deformation. These conclusions are supported by transmission electron microscope studies of the wear tracks as well as by nanoindentation measurements.

  2. First Ti-XANES analyses of refractory inclusions from Murchison

    International Nuclear Information System (INIS)

    Simon, S.B.; Sutton, S.R.; Grossman, L.

    2009-01-01

    Ti valence in refractory phases is an important recorder of redox conditions in the early solar nebula. We report the valence of Ti in pyroxene, spinel and hibonite in spinel-hibonite and spinel-pyroxene inclusions and in a coarse hibonite grain. A system of solar composition is so reducing that Ti 3+ and Ti 4+ can coexist, making the valence of Ti a valuable indicator of f O2 conditions during formation of nebular materials. The Ti 3+ /Ti 4+ ratios observed in the Ti-rich phases fassaite and rhoenite in coarse-grained refractory inclusions from CV3 chondrites have been shown to be quantitatively consistent with formation in a gas of solar composition (log f O2 = IW-6.8), but these are the only objects in chondrites for which this is the case. Here, we report the valence of Ti in various phases in refractory inclusions from the Murchison CM2 chondrite. The second-highest temperature, major-element-bearing phase predicted to condense from a gas of solar composition, hibonite (ideally CaAl 12 O 19 ), can contain significant amounts of Ti, but the hibonite structure can have oxygen vacancies, so calculation of Ti valence from stoichiometry of electron probe analyses is not recommended for hibonite. To date, the only reported measurement of Ti valence in meteoritic hibonite was done by electron spin resonance, on coarse crystals from a Murchison hibonite-perovskite-melilite inclusion. Spinel and most of the pyroxene in CM inclusions contain too little Ti for derivation of Ti 3+ /Ti 4+ ratios from electron probe analyses. X-ray absorption near edge spectroscopy (XANES), however, allows determination of Ti valence in relatively Ti-poor phases. In the present work, we apply synchrotron microXANES to a large hibonite grain from Murchison and to spinel-hibonite (sp-hib) and spinel-pyroxene (sp-pyx) inclusions from Murchison, refractory materials whose Ti 3+ /Ti 4+ ratios have not been previously measured. Analysis of these samples allows comparison of Ti valence of (1

  3. Microstructure and mechanical properties of in situ TiC and Nd2O3 particles reinforced Ti-4.5 wt.%Si alloy composites

    International Nuclear Information System (INIS)

    Zhang, Xinjiang; Li, Yibin; Song, Guangping; Sun, Yue; Peng, Qingyu; Li, Yuxin; He, Xiaodong

    2011-01-01

    Highlights: → (TiC + Nd 2 O 3 )/Ti-4.5 wt.%Si composites were in situ synthesized. → The phase components and microstructures of the composites were investigated. → In situ reinforcements improve the mechanical properties of the matrix alloy. -- Abstract: (TiC + Nd 2 O 3 )/Ti-4.5 wt.%Si composites were in situ synthesized by a non-consumable arc-melting technology. The phases in the composites were identified by X-ray diffraction. Microstructures of the composites were observed by optical microscope and scanning electron microscope. The composite contains four phases: TiC, Nd 2 O 3 , Ti 5 Si 3 and Ti. The TiC and Nd 2 O 3 particles with dendritic and near-equiaxed shapes are well distributed in Ti-4.5 wt.%Si alloy matrix, and the fine Nd 2 O 3 particles exist in the network Ti + Ti 5 Si 3 eutectic cells and Ti matrix of the composites. The hardness and compressive strength of the composites are markedly higher than that of Ti-4.5 wt.%Si alloy. When the TiC content is fixed as 10 wt.% in the composites, the hardness is enhanced as the Nd 2 O 3 content increases from 8 wt.% to 13 wt.%, but the compressive strength peaks at the Nd 2 O 3 content of 8 wt.%.

  4. LCAO calculations of SrTiO3 nanotubes

    International Nuclear Information System (INIS)

    Evarestov, Robert; Bandura, Andrei

    2011-01-01

    The large-scale first-principles simulation of the structure and stability of SrTiO 3 nanotubes is performed for the first time using the periodic PBE0 LCAO method. The initial structures of the nanotubes have been obtained by the rolling up of the stoichiometric SrTiO 3 slabs consisting of two or four alternating (001) SrO and TiO 2 atomic planes. Nanotubes (NTs) with chiralities (n,0) and (n,n) have been studied. Two different NTs were constructed for each chirality: (I) with SrO outer shell, and (II) with TiO 2 outer shell. Positions of all atoms have been optimized to obtain the most stable NT structure . In the majority of considered cases the inner or outer TiO 2 shells of NT undergo a considerable reconstruction due to shrinkage or stretching of interatomic distances in the initial cubic perovskite structure. There were found two types of surface reconstruction: (1) breaking of Ti-O bonds with creating of Ti = O titanyl groups in outer surface; (2) inner surface folding due to Ti-O-Ti bending. Based on strain energy calculations the largest stability was found for (n,0) NTs with TiO 2 outer shell.

  5. Structural analysis of a coating of TiN over a Cu-Ti-Cr alloy: Study of the Cu-Ti interphase

    International Nuclear Information System (INIS)

    Villegas Vejar, C; Suazo, A; Radtk, H; Carrasco, C

    2004-01-01

    The crystalline structure of a thin film of TiN deposited by DC planar magnetron sputtering over a ternary copper alloy was studied. A fine film of titanium was deposited between the coating and the substrate for better adherence. The samples were analyzed with a transmission electron microscope to determine the structure of each of the components as well as the network distortion in the Cu-Ti interphase. The results were complemented with previous X-ray diffraction analyses to identify the network parameter for each of the study components and the respective residual tensions. This study shows the agreement between the network distortion and the residual tensions that were measured, and also relates the theory of crystalline coherence with the experimentally calculated break down by electron diffraction in the Cu-Ti interphase (CW)

  6. One-Step Nonaqueous Synthesis of Pure Phase TiO2 Nanocrystals from TiCl4 in Butanol and Their Photocatalytic Properties

    Directory of Open Access Journals (Sweden)

    Tieping Cao

    2011-01-01

    Full Text Available Pure phase TiO2 nanomaterials were synthesized by an autoclaving treatment of TiCl4 with butanol as a single alcohol source. It was found that the control of molar ratio of TiCl4 to butanol played an important role in determining the TiO2 crystal phase and morphology. A high molar ratio of TiCl4 to butanol favored the formation of anatase nanoparticles, whereas rutile nanorods were selectively obtained at a low molar ratio of TiCl4 to butanol. Evaluation of the photocatalytic activity of the synthesized TiO2 was performed in terms of decomposition of organic dye rhodamine B under ultraviolet irradiation. It turned out that the as-synthesized TiO2 crystallites possessed higher photocatalytic activities toward bleaching rhodamine B than Degussa P25, benefiting from theirhigh surface area, small crystal size as well as high crystallinity.

  7. Synthesis of Ag-loaded SrTiO{sub 3}/TiO{sub 2} heterostructure nanotube arrays for enhanced photocatalytic performances

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Zijun; Chen, Da; Zhan, Xiaqiang; Wang, Fang; Qin, Laishun; Huang, Yuexiang [China Jiliang University, College of Materials Science and Engineering, Hangzhou, Zhejiang (China)

    2017-06-15

    In this work, the effect of loading Ag nanoparticles on the photocatalytic activity of SrTiO{sub 3}/TiO{sub 2} nanotube arrays (TNTAs) was investigated. TNTAs were partially transformed to SrTiO{sub 3} through a hydrothermal treatment, which could preserve the tubular structure of TNTAs, and then, Ag nanoparticles were well deposited on the surface of SrTiO{sub 3}/TNTAs heterostructure by a chemical reduction process. Compared to the TNTAs sample, the Ag-loaded SrTiO{sub 3}/TNTAs sample showed significantly enhanced photocatalytic activities for photodegradation of rhodamine B. The enhanced photocatalytic activity of Ag-loaded SrTiO{sub 3}/TNTAs could be attributed to the increased optical absorption as well as the efficient charge transfer and separation of photogenerated electron-hole pairs induced by the SrTiO{sub 3}/TNTAs heterojunction and the Schottky barrier between metallic Ag and SrTiO{sub 3}/TNTAs. On the basis of the trapping experiments, the possible photocatalytic mechanism was also discussed. (orig.)

  8. Microstructure of two phases alloy Al{sub 3}Ti/Al{sub 3}Ti{sub 0.75}Fe{sub 0.25}; Microestructura de una aleacion de dos fases Al{sub 3}Ti/Al{sub 3}Ti{sub 0.75}Fe{sub 0.25}

    Energy Technology Data Exchange (ETDEWEB)

    Angeles, C; Rosas, G; Perez, R [Instituto Nacional de Investigaciones Nucleares, Departamento de Sintesis y Caracterizacion de Materiales, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    1998-07-01

    The titanium-aluminium system presents three intermetallic compounds from those Al{sub 3}Ti is what less attention has received. The objective of this work is to generate and characterize the microstructure of multiphase alloys nearby to Al{sub 3}Ti compound through Fe addition as alloying. This is because it has been seen that little precipitates of Al{sub 2}Ti phase over Al{sub 3}Ti intermetallic compound increases its ductility. (Author)

  9. Characterization of Sputtered Nickel-Titanium (NiTi) Stress and Thermally Actuated Cantilever Bimorphs Based on NiTi Shape Memory Alloy (SMA)

    Science.gov (United States)

    2015-11-01

    necessary anneal . Following this, a thin film of NiTi was blanket sputtered at 600 °C. This NiTi blanket layer was then wet -etch patterned using a...varying the sputter parameters during NiTi deposition, such as thickness, substrate temperature during deposition and anneal , and argon pressure during...6 Fig. 4 Surface texture comparison between NiTi sputtered at RT, then annealed at 600 °C, and NiTi

  10. Oxidation behaviors of the TiNi/Ti_2Ni matrix composite coatings with different contents of TaC addition fabricated on Ti6Al4V by laser cladding

    International Nuclear Information System (INIS)

    Lv, Y.H.; Li, J.; Tao, Y.F.; Hu, L.F.

    2016-01-01

    The TiNi/Ti_2Ni matrix composite coatings were fabricated on Ti6Al4V by laser cladding the mixtures of NiCrBSi and different contents of TaC (0 wt%, 5 wt%, 15 wt%, 30 wt% and 40 wt%). Scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and X-ray diffractometry (XRD) were used to examine the microstructures of the coatings. Oxidation behaviors of these coatings were also investigated at 800 °C for 50 h in air. The results showed that the coating without TaC addition was mainly composed of TiNi/Ti_2Ni as the matrix and TiC/TiB_2/TiB as the reinforcement. TaC was dissolved completely and precipitated again during laser cladding. Ta and C from the added TaC mainly existed as the solute atoms in the solid solutions of TiC, TiB_2 and TiB in the coatings with TaC addition. The addition of TaC refined the microstructures of the coatings. In the oxidation test, the oxidation process was divided into the violent oxidation stage and the slow oxidation stage. The oxidation rates of the substrate and the coatings with different contents of TaC (0, 5, 15, 30, 40 wt%) were 0.644, 0.287, 0.173, 0.161, 0.223 and 0.072 mg cm"−"2 h"−"1 in the first stage, 0.884, 0.215, 0.136, 0.126, 0.108 and 0.040 mg"2 cm"−"4 h"−"1 in the second stage, respectively. The weight gain of these samples were 6.70, 3.30, 2.86, 2.64, 2.41 and 1.69 mg cm"−"2, respectively after the whole oxidation test. The oxidation film formed on the surface of the coating without TaC addition mainly consisted of TiO_2, Al_2O_3, and a small amount of NiO, Cr_2O_3 and SiO_2. Moreover, Ta_2O_5 was also formed on the surfaces of these coatings with different contents of TaC. The oxides formed during the oxidation test were supposed to be responsible for the improvement in oxidation resistance of these coatings. - Highlights: • The composite coatings with TaC addition were fabricated on Ti6Al4V by laser cladding. • Effect of TaC addition on microstructural evolution of the coatings was

  11. Mechanical Properties of TiTaHfNbZr High-Entropy Alloy Coatings Deposited on NiTi Shape Memory Alloy Substrates

    Science.gov (United States)

    Motallebzadeh, A.; Yagci, M. B.; Bedir, E.; Aksoy, C. B.; Canadinc, D.

    2018-04-01

    TiTaHfNbZr high-entropy alloy (HEA) thin films with thicknesses of about 750 and 1500 nm were deposited on NiTi substrates by RF magnetron sputtering using TiTaHfNbZr equimolar targets. The thorough experimental analysis on microstructure and mechanical properties of deposited films revealed that the TiTaHfNbZr films exhibited amorphous and cauliflower-like structure, where grain size and surface roughness increased concomitant with film thickness. More importantly, the current findings demonstrate that the TiTaHfNbZr HEA films with mechanical properties of the same order as those of the NiTi substrate constitute promising biomedical coatings effective in preventing Ni release.

  12. Mechanical Properties of TiTaHfNbZr High-Entropy Alloy Coatings Deposited on NiTi Shape Memory Alloy Substrates

    Science.gov (United States)

    Motallebzadeh, A.; Yagci, M. B.; Bedir, E.; Aksoy, C. B.; Canadinc, D.

    2018-06-01

    TiTaHfNbZr high-entropy alloy (HEA) thin films with thicknesses of about 750 and 1500 nm were deposited on NiTi substrates by RF magnetron sputtering using TiTaHfNbZr equimolar targets. The thorough experimental analysis on microstructure and mechanical properties of deposited films revealed that the TiTaHfNbZr films exhibited amorphous and cauliflower-like structure, where grain size and surface roughness increased concomitant with film thickness. More importantly, the current findings demonstrate that the TiTaHfNbZr HEA films with mechanical properties of the same order as those of the NiTi substrate constitute promising biomedical coatings effective in preventing Ni release.

  13. Analysis of annealing effects on osseointegration in vitro of TiO{sub 2} coatings formed from Ti ATSM F67 e Ti ATSM F67

    Energy Technology Data Exchange (ETDEWEB)

    Simon, Anna Paulla; Lima, Amanda Santos de; Sikora, Mariana de Souza, E-mail: anna17simon@gmail.com [Universidade Tecnologica Federal do Parana (UTFPR), PR (Brazil)

    2016-07-01

    Full text: Amorphous TiO{sub 2} coatings can be converted to crystalline phases submitting the samples to annealing (heat treatment). These crystalline structures improve structural conformation of atoms being significantly efficient in terms of osseointegration. To analyse the annealing treatment effects on osseointegration, Ti ATSM F67 e Ti ATSM F67 were submitted to potentiostatic anodization in organic media containing 0.5 and 0.75 % w/w of NH-4F and 10 % w/w of water, applying 25 V during 90 minutes, using static and stirring methods. The annealing was performed using a temperature ramp of 2 °C/min until it reaches 450 °C, remaining in this condition during 2 hours, with ambient cooling. The samples were examined by SEM and XRD. After the characterization, the synthesized films were subjected to immersion tests in simulated body fluid (SBF) during 1 and 2 weeks in order to qualitatively evaluate the in vitro osseointegration capacity. The results show that TiO{sub 2} porous films can be formed, except for the film grown on Ti ASTM F136 using a NH{sub 4}F concentration of 0.75 % w/w with stirring. This result can be explained by aggressive homogeneous dissolution in the entire surface of the film, once the reaction is no longer limited by diffusion. The films as-formed are amorphous, being necessary the annealing to convert the oxide to its crystalline phases. With the annealing the amorphous oxide was converted to the crystalline anatase phase in all synthesized films, but in different proportions. It was observed that films grown from Ti ASTM F136 have shown lower crystallinity due to phase stabilizers which compose the alloy. So TiO{sub 2} grown from Ti ATSM F67 presents higher quantities of crystalline phase tending to show higher hydrophilic aspects, what contributed to the better osseointegration as observed in this work, qualitatively evaluated by the extent and amount of deposited hydroxyapatite on surface. (author)

  14. Precipitation evolution in a Ti-free and Ti-containing stainless maraging steel

    International Nuclear Information System (INIS)

    Schober, M.; Schnitzer, R.; Leitner, H.

    2009-01-01

    Stainless maraging steels have a Cr content higher than 12 wt% and show a excellent combination of high strength and ductility, which make them attractive for use in machinery fields and aircraft applications. The massive increase of strength during ageing treatment of maraging steels is related to a precipitation sequence of various nm-scaled intermetallic phases. The peak hardness especially in Ti-containing maraging steels can be reached after short-time ageing at temperatures around 500 o C. However, precipitation reactions in different stainless maraging steels are not fully understood, especially the evolution from clustering over growing to coarsening. In the present work a commercial maraging steel and a Ti-containing model alloy are investigated and compared to each other. The steels were isothermally heat treated at 525 o C for a range of times. Special emphasis was laid on the correlation of hardness to the formation and presence of different kinds of precipitates. The isothermal aged samples were investigated by using two advanced three-dimensional energy compensated atom probes (LEAP TM and 3DAP TM ) both in voltage mode and in laser mode. The atom probe data were correlated to standard hardness measurements. The results show that the partial substitution of Al by Ti results in a different precipitation behaviour. While the Ti-free maraging steel exhibit only one type of precipitate, the Ti-containing grade shows a change in the type of precipitates during ageing. However, this change leads to an accelerated coarsening and thus to a faster drop in hardness.

  15. Precipitation evolution in a Ti-free and Ti-containing stainless maraging steel.

    Science.gov (United States)

    Schober, M; Schnitzer, R; Leitner, H

    2009-04-01

    Stainless maraging steels have a Cr content higher than 12wt% and show a excellent combination of high strength and ductility, which make them attractive for use in machinery fields and aircraft applications. The massive increase of strength during ageing treatment of maraging steels is related to a precipitation sequence of various nm-scaled intermetallic phases. The peak hardness especially in Ti-containing maraging steels can be reached after short-time ageing at temperatures around 500 degrees C. However, precipitation reactions in different stainless maraging steels are not fully understood, especially the evolution from clustering over growing to coarsening. In the present work a commercial maraging steel and a Ti-containing model alloy are investigated and compared to each other. The steels were isothermally heat treated at 525 degrees C for a range of times. Special emphasis was laid on the correlation of hardness to the formation and presence of different kinds of precipitates. The isothermal aged samples were investigated by using two advanced three-dimensional energy compensated atom probes (LEAP and 3DAP) both in voltage mode and in laser mode. The atom probe data were correlated to standard hardness measurements. The results show that the partial substitution of Al by Ti results in a different precipitation behaviour. While the Ti-free maraging steel exhibit only one type of precipitate, the Ti-containing grade shows a change in the type of precipitates during ageing. However, this change leads to an accelerated coarsening and thus to a faster drop in hardness.

  16. Anatase-TiO{sub 2} nanocoating of Li{sub 4}Ti{sub 5}O{sub 12} nanorod anode for lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Ming-ming, E-mail: chmm@tju.edu.cn; Sun, Xin; Qiao, Zhi-jun; Ma, Qian-qian; Wang, Cheng-yang

    2014-07-15

    Highlights: • TiO{sub 2}-coated LTO was in-situ prepared via a microemulsion-assisted hydrothermal route. • Anatase-TiO{sub 2} coating layer enhances the electrochemical performance of Li{sub 4}Ti{sub 5}O{sub 12}. • The as-prepared sample presents high-rate capability and cyclic stability. - Abstract: Li{sub 4}Ti{sub 5}O{sub 12} nanorod coated by anatase-TiO{sub 2} is in situ synthesized via a microemulsion-assisted hydrothermal method followed by heat treatment at 550 °C in air. Compared with pure Li{sub 4}Ti{sub 5}O{sub 12}, Li{sub 4}Ti{sub 5}O{sub 12} nanorod coated by anatase-TiO{sub 2} presents much improved electrochemical characteristics in terms of high specific capacity, excellent rate capability and cyclic stability (96.0% of initial capacity at a current density of 1.75 A g{sup −1} up to 100 cycles). Acting as a perfect nanocoating layer, anatase-TiO{sub 2} contributes some capacity and gives an enhanced performance to the Li{sub 4}Ti{sub 5}O{sub 12} electrode. All the results suggest that Li{sub 4}Ti{sub 5}O{sub 12} nanorod coated by anatase-TiO{sub 2} could be suitable for use as a high-rate anode material for lithium-ion batteries.

  17. Biocorrosion of TiO2 nanoparticle coating of Ti-6Al-4V in DMEM under specific in vitro conditions

    Science.gov (United States)

    Höhn, Sarah; Virtanen, Sannakaisa

    2015-02-01

    A TiO2 nanoparticle coating was prepared on a biomedical Ti-6Al-4V alloy using "spin-coating" technique with a colloidal suspension of TiO2 nanopowders with the aim to optimize the surface morphology (e.g., roughness) for improved biocompatibility. The influence of a TiO2 nanoparticle (NP) coating on the corrosion behavior, metal ion release, and biomimetic apatite formation was studied in DMEM, at 37.5 °C with a continuous supply of 5% CO2. Electrochemical impedance spectroscopy measurements indicate a formation of a new layer on the surface of the NP-coated sample upon 28 days immersion in DMEM. Scanning electron microscopy (SEM) and X-ray spectroscopy confirm that the surface of the NP-coated Ti-6Al-4V shows a complete coverage by a Ca-phosphate layer in contrast to the non-coated Ti-6Al-4V alloy. Hence, the TiO2-NP coating strongly enhances biomimetic apatite formation on the alloy surface. In addition, the TiO2-NP coating can efficiently reduce Al-release from the alloy, for which the bare Ti-6Al-4V alloy is significant for at least 28 days of immersion in DMEM.

  18. Thermodynamic and lattice parameter calculation of TiC x produced from Al-Ti-C powders by laser igniting self-propagating high-temperature synthesis

    International Nuclear Information System (INIS)

    Li, Y.X.; Hu, J.D.; Wang, H.Y.; Guo, Z.X.; Chumakov, A.N.

    2007-01-01

    TiC x has been formed by self-propagating high-temperature synthesis (SHS) from elemental powder mixtures with a range of C/Ti ratios. The combusting behavior of the powder mixtures was investigated. The effect of the processing variables on the lattice parameter and the composition of TiC were examined. The results show that lattice parameters of TiC x increase with the increase of C/Ti ratio. The variation of Gibbs free energy in Al-Ti-C system was studied based on the thermodynamics theory. The results show that TiC and Al 3 Ti phases are easier to form than Al 4 C 3 phase

  19. Heterogeneous nucleation of solid Al from the melt by TiB2 and Al3Ti: An ab initio molecular dynamics study

    KAUST Repository

    Wang, Junsheng; Horsfield, Andrew; Lee, Peter D.; Schwingenschlö gl, Udo

    2010-01-01

    The nucleation of solid Al from the melt by TiB2 is well established and is believed to involve the formation of Al3Ti. Since the atomic-scale mechanisms involved are not fully understood, we look to computer simulation to provide insight. As there is an absence of suitable potentials for all of this complex system we have performed large-scale density-functional-theory molecular dynamics simulations of the nucleation of solid Al from the melt on TiB2 and Al3Ti substrates at undercoolings of around 2 K. Using periodic boundary conditions, we find limited ordering and no signs of incipient growth in the liquid Al close to the B-terminated surface of TiB2. By contrast, we see fcc-like ordering near the Ti-terminated surface, with growth being frustrated by the lattice mismatch between bulk Al and the TiB2 substrate. The Al interatomic distances at the Ti-terminated surface are similar to distances found in Al3Ti; we suggest that the layer encasing TiB2 observed experimentally may be strained Al on a Ti-terminated surface rather than Al3Ti. For the Al3Ti substrate, fcc-like structures are observed on both sides which extend rapidly into the melt. Periodic boundaries introduce unphysical stresses which we removed by introducing a vacuum region to separate the liquid from the solid at one of the interfaces. We see ordering in the Al on both the B-terminated (0001) surface of TiB2, and on Al3Ti(112), with the ordering able to be stronger on the Al3Ti substrate. However, we cannot draw strong conclusions as these simulations need more time to allow long-ranged fluctuations in the liquid Al to dampen out. The huge computational cost restricted the range and duration of simulations that was possible.

  20. Heterogeneous nucleation of solid Al from the melt by TiB2 and Al3Ti: An ab initio molecular dynamics study

    KAUST Repository

    Wang, Junsheng

    2010-11-16

    The nucleation of solid Al from the melt by TiB2 is well established and is believed to involve the formation of Al3Ti. Since the atomic-scale mechanisms involved are not fully understood, we look to computer simulation to provide insight. As there is an absence of suitable potentials for all of this complex system we have performed large-scale density-functional-theory molecular dynamics simulations of the nucleation of solid Al from the melt on TiB2 and Al3Ti substrates at undercoolings of around 2 K. Using periodic boundary conditions, we find limited ordering and no signs of incipient growth in the liquid Al close to the B-terminated surface of TiB2. By contrast, we see fcc-like ordering near the Ti-terminated surface, with growth being frustrated by the lattice mismatch between bulk Al and the TiB2 substrate. The Al interatomic distances at the Ti-terminated surface are similar to distances found in Al3Ti; we suggest that the layer encasing TiB2 observed experimentally may be strained Al on a Ti-terminated surface rather than Al3Ti. For the Al3Ti substrate, fcc-like structures are observed on both sides which extend rapidly into the melt. Periodic boundaries introduce unphysical stresses which we removed by introducing a vacuum region to separate the liquid from the solid at one of the interfaces. We see ordering in the Al on both the B-terminated (0001) surface of TiB2, and on Al3Ti(112), with the ordering able to be stronger on the Al3Ti substrate. However, we cannot draw strong conclusions as these simulations need more time to allow long-ranged fluctuations in the liquid Al to dampen out. The huge computational cost restricted the range and duration of simulations that was possible.

  1. Prediction of two-dimensional electron gas mediated magnetoelectric coupling at ferroelectric PbTiO3/SrTiO3 heterostructures

    Science.gov (United States)

    Wei, Lan-ying; Lian, Chao; Meng, Sheng

    2017-05-01

    First-principles calculations predict the emergence of magnetoelectric coupling mediated by two-dimensional electron gas (2DEG) at the ferroelectric PbTiO3/SrTiO3 heterostructure. Free electrons endowed by naturally existing oxygen vacancies in SrTiO3 are driven to the heterostructure interface under the polarizing field of ferroelectric PbTiO3 to form a 2DEG. The electrons are captured by interfacial Ti atoms, which surprisingly exhibits ferromagnetism even at room temperature with a small critical density of ˜15.5 μ C /cm2 . The ferroelectricity-controlled ferromagnetism mediated by interfacial 2DEG shows strong magnetoelectric coupling strength, enabling convenient control of magnetism by electric field and vice versa. The PbTiO3/SrTiO3 heterostructure is cheap, easily grown, and controllable, promising future applications in low-cost spintronics and information storage at ambient condition.

  2. Native SrTiO3 (001) surface layer from resonant Ti L2,3 reflectance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Valvidares, Manuel; Huijben, Mark; Yu, Pu; Ramesh, Ramamoorthy; Kortright, Jeffrey

    2010-11-03

    We quantitatively model resonant Ti L2,3 reflectivity Rs,p(q, hn) from several SrTiO3 (001) single crystals having different initial surface preparations and stored in ambient conditions before and between measurements. All samples exhibit unexpected 300 K Rs(hn) - Rp(hn) anisotropy corresponding to weak linear dichroism and tetragonal distortion of the TiO6 octahedra indicating a surface layer with properties different from cubic SrTiO3. Oscillations in Rs(q) confirm a ubiquitous surface layer 2-3 nm thick that evolves over a range of time scales. Resonant optical constant spectra derived from Rs,p(hn) assuming a uniform sample are refined using a single surface layer to fit measured Rs(q). Differences in surface layer and bulk optical properties indicate that the surface is significantly depleted in Sr and enriched in Ti and O. While consistent with the tendency of SrTiO3 surfaces toward non-stoichiometry, this layer does not conform simply to existing models for the near surface region and apparently forms via room temperature surface reactions with the ambient. This new quantitative spectral modeling approach is generally applicable and has potential to study near-surface properties of a variety of systems with unique chemical and electronic sensitivities.

  3. A graded nano-TiN coating on biomedical Ti alloy: Low friction coefficient, good bonding and biocompatibility.

    Science.gov (United States)

    Cui, Wenfang; Qin, Gaowu; Duan, Jingzhu; Wang, Huan

    2017-02-01

    In order to solve wear resistance of Ti alloy biomaterials, the concept of a graded nano-TiN coating has been proposed. The coating was prepared on Ti-6Al-4V bio-alloy by DC reactive magnetron sputtering. The wear performance of the coated specimens was measured in Hank's solution under the load of 10N, and the biocompatibility was evaluated according to ISO-10993-4 standard. The results show that the gradient coating exhibits a gradual change in compositions and microstructures along the direction of film growth. Nano-TiN with the size of several to dozens nanometers and Ti 4 N 3-x transitional phase with variable composition form a graded composite structure, which significantly improves adhesion strength (L c1 =80N, L c2 =120N), hardness (21GPa) and anti-wear performance (6.2×10 -7 mm 3 /Nm). The excellent bonding and wear resistance result from a good match of mechanical properties at substrate/coating interface and the strengthening and toughening effects of the nanocrystalline composite. The nano-TiN coating has also been proved to have good biocompatibility through in-vitro cytotoxicity, hemocompatibility and general toxicity tests. And thus, the proposed graded nano-TiN coating is a good candidate improving wear resistance of many implant medical devices. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Infiltrated TiC/Cu composites

    International Nuclear Information System (INIS)

    Frage, N.; Froumin, N.; Rubinovich, L.; Dariel, M.P.

    2001-01-01

    One approach for the fabrication of ceramic-metal composites is based on the pressureless impregnation of a porous ceramic preform by a molten metal. Molten Cu does not react with TiC and the wetting angle is close to 90 o . Nonetheless, molten Cu readily impregnates partially sintered TiC preforms. A model that describes the dependence of the critical contact angle for spontaneous impregnation by molten metals in partially sintered preforms on the level of densification and on the morphology of the particles was developed. For high aspect ratios of the particles forming the preform, wetting angles close to 90 o still allow impregnation by the molten metal. The results of the model were confirmed by infiltration of partially sintered TiC preforms with molten Cu and by fabrication of the TiC/Cu composites with various ceramic-to metal ratios. Decreasing of the metal content in the composite from 50 vol.% to 10 vol.% leads to a hardness increase from 250 to 1800 HV, and to the decrease of the bending strength from 960 to 280 MPa. The resistivity of these TiC/Cu composites decreases from 142 ohm cm to 25 ohm cm. (author)

  5. Transparent TiO2 nanowire networks via wet corrosion of Ti thin films for dye-sensitized solar cells

    Science.gov (United States)

    Shin, Eunhye; Jin, Saera; Hong, Jongin

    2017-09-01

    Transparent TiO2 nanowire networks were prepared by corrosion of Ti thin films on F-doped SnO2 glass substrates in an alkaline (potassium hydroxide: KOH) solution. The formation of the porous TiO2 nanostructures from the Ti thin films was thoroughly investigated. Dye-sensitized solar cells with a photoanode of 1.2-μm-thick nanowire networks exhibit an average optical transmittance of 40% in the visible light region and a power conversion efficiency of 1.0% under one sun illumination.

  6. Biocorrosion studies of TiO{sub 2} nanoparticle-coated Ti-6Al-4V implant in simulated biofluids

    Energy Technology Data Exchange (ETDEWEB)

    Zaveri, Nikita; McEwen, Gerald D.; Karpagavalli, Ramji; Zhou Anhong, E-mail: Anhong.Zhou@usu.ed [Utah State University, Biological Engineering Program (United States)

    2010-06-15

    The corrosion behaviors of the TiO{sub 2} nanoparticles coated bioimplant Ti-6Al-4V exposed to three different simulated biofluids (SBF), namely, (1) NaCl solution, (2) Hank's solution, and (3) Cigada solution, were studied by using micro-Raman spectroscopy, electrochemical techniques, and scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS). The different electrochemical impedance spectroscopy models were applied to fit the data obtained from the implants before and after the coating of TiO{sub 2} nanoparticles (50-100 nm). It was found that the TiO{sub 2} nanoparticle coatings increased the thickness of the pre-existing oxide layer on the Ti-6Al-4V surface, serving to improve the bioimplant corrosion resistance.

  7. Photoluminescence properties of TiO{sub 2} nanofibers

    Energy Technology Data Exchange (ETDEWEB)

    Chetibi, Loubna [University Mentouri Constantine and National Polytechnic School of Constantine, Materials Science and Applications Unit (Algeria); Busko, Tetiana; Kulish, Nikolay Polikarpovich [Kyiv National Taras Shevchenko University (Ukraine); Hamana, Djamel [University Mentouri Constantine and National Polytechnic School of Constantine, Materials Science and Applications Unit (Algeria); Chaieb, Sahraoui [Lawrence Berkeley National Laboratory (United States); Achour, Slimane, E-mail: achourslimane11@yahoo.fr [University Mentouri Constantine and National Polytechnic School of Constantine, Materials Science and Applications Unit (Algeria)

    2017-04-15

    Multi-walled carbon nanotube (MWCNT)-TiO{sub 2} nanofiber (NF) composites forming a layered nanostructure (MWCNTs/TiO{sub 2} NFs/Ti) were prepared by impregnation at low temperature. Room temperature photoluminescence (PL) of these nanostructures shows a broad intense band in the visible light range (∼450–600 nm). The origin of the PL emission which, mainly, resulted from surface oxygen vacancies and other defects was investigated. We studied the effect of MWCNT deposition on the PL of TiO{sub 2} NFs where the MWCNTs can act as an electron reservoir of electrons emitted from TiO{sub 2} nanofibers when irradiated with UV light. The combination of MWCNTs and TiO{sub 2} results in quenching of TiO{sub 2} luminescence in the visible range. In addition, the prepared surface of MWCNTs-TiO{sub 2} was irradiated with Ti{sup +} ions using irradiation energy of 140 keV and doses of 10{sup 13} ions/cm{sup 2}. Also, this treatment induced the PL intensity quenching due to the generation of non-radiative additional levels inside the band gap.

  8. Aeronautical Cast Ti Alloy and Forming Technology Development

    OpenAIRE

    ZHANG Meijuan; NAN Hai; JU Zhongqiang; GAO Fuhui; QIE Xiwang; ZHU Langping

    2016-01-01

    The application and feature of Ti alloy and TiAl alloy for aviation at home and abroad were briefly introduced. According to the patent application status in Ti alloy field, the development of Ti alloy casting technology was analyzed in the recent thirty years, especially the transformation in aviation. Along with the development of aeronautional manufacturing technology and demand of high performance aircraft, Ti alloy casting is changing towards to be large, integral and complicated, and th...

  9. The core structures of transformation dislocations at TiAl/Ti3Al interfaces

    International Nuclear Information System (INIS)

    Penisson, J.M.; Loubradou, M.; Derder, C.; Bonnet, R.

    1993-01-01

    A Ti-40%Al alloy is investigated using High Resolution Electron Microscopy. The alloy structure consists mainly of alternate lamellae of γ(TiAl, L1 0 structure) and α 2 (Ti 3 Al, DO 19 structure) phases. These lamellae are parallel to each other and the interfaces between them are flat and parallel to the densest planes of the crystals. It is found that, among the variety of interfacial dislocations relieving the misfit, some have cores involving four (111) planes in height. The elastic displacement fields around these interfacial ledges, compared with the experimental atomic positions determined from HREM images, are in agreement with Burgers vector contents 1/6 left angle 112 right angle . (orig.)

  10. The Effect of Process Parameters on the Synthesis of Ti and TiO2 Nanoparticles Producted by Electromagnetic Levitational Gas Condensation

    Directory of Open Access Journals (Sweden)

    Maryam Moazeni

    2012-10-01

    Full Text Available The nanoparticles of Ti and TiO2 have attracted extensive research interest because of their diverse applications in, for instance, catalysis, energy conversion, pigment and cosmetic manufacturing and biomedical engineering. Through this project, a one-step bulk synthesis method of electromagnetic levitational gas condensation (ELGC was utilized for the synthesis of monodispersed and crystalline Ti and TiO2 nanoparticles. Within the process, the Ti vapours ascending from the high temperature levitated droplet were condensed by an argon gas stream under atmospheric pressure. The TiO2 nanoparticles were produced by simultaneous injection of argon and oxygen into the reactor. The effects of flow rate of the condensing and oxidizing gases on the size and the size distribution of the nanoparticles were investigated. The particles were characterized by scanning electron microscopy (SEM, X-ray diffraction (XRD and image analysis. The process parameters for the synthesis of the crystalline Ti and TiO2 nanoparticles were determined.

  11. Fate of pristine TiO2 nanoparticles and aged paint-containing TiO2 nanoparticles in lettuce crop after foliar exposure.

    Science.gov (United States)

    Larue, Camille; Castillo-Michel, Hiram; Sobanska, Sophie; Trcera, Nicolas; Sorieul, Stéphanie; Cécillon, Lauric; Ouerdane, Laurent; Legros, Samuel; Sarret, Géraldine

    2014-05-30

    Engineered TiO2 nanoparticles (TiO2-NPs) are present in a large variety of consumer products, and are produced in largest amount. The building industry is a major sector using TiO2-NPs, especially in paints. The fate of NPs after their release in the environment is still largely unknown, and their possible transfer in plants and subsequent impacts have not been studied in detail. The foliar transfer pathway is even less understood than the root pathway. In this study, lettuces were exposed to pristine TiO2-NPs and aged paint leachate containing TiO2-NPs and microparticles (TiO2-MPs). Internalization and in situ speciation of Ti were investigated by a combination of microscopic and spectroscopic techniques. Not only TiO2-NPs pristine and from aged paints, but also TiO2-MPs were internalized in lettuce leaves, and observed in all types of tissues. No change in speciation was noticed, but an organic coating of TiO2-NPs is likely. Phytotoxicity markers were tested for plants exposed to pristine TiO2-NPs. No acute phytotoxicity was observed; variations were only observed in glutathione and phytochelatin levels but remained low as compared to typical values. These results obtained on the foliar uptake mechanisms of nano- and microparticles are important in the perspective of risk assessment of atmospheric contaminations. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. In-situ formation of Ni4Ti3 precipitate and its effect on pseudoelasticity in selective laser melting additive manufactured NiTi-based composites

    Science.gov (United States)

    Gu, Dongdong; Ma, Chenglong

    2018-05-01

    Selective laser melting (SLM) additive manufacturing technology was applied to synthesize NiTi-based composites via using ball-milled Ti, Ni, and TiC mixed powder. By transmission electron microscope (TEM) characterization, it indicated that the B2 (NiTi) matrix was obtained during SLM processing. In spite of more Ti content (the Ti/Ni ratio >1), a mass of Ni-rich intermetallic compounds containing Ni4Ti3 with nanostructure features and eutectic Ni3Ti around in-situ Ti6C3.75 dendrites were precipitated. Influence of the applied laser volume energy density (VED) on the morphology and content of Ni4Ti3 precipitate was investigated. Besides, nanoindentation test of the matrix was performed in order to assess pseudoelastic recovery behavior of SLM processed NiTi-based composites. At a relatively high VED of 533 J/mm3, the maximum pseudoelastic recovery was obtained due to the lowest content of Ni4Ti3 precipitates. Furthermore, the precipitation mechanism of in-situ Ni4Ti3 was present based on the redistribution of titanium element and thermodynamics analysis, and then the relationship of Ni4Ti3 precipitate, VED and pseudoelastic recovery behavior was also revealed.

  13. Influence of oxide and alloy formation on the Electrochemistry of Ti deposition from the NaCl-KCl-NaF-K-2 TiF6 melt reduced by metallic Ti

    DEFF Research Database (Denmark)

    Barner, Jens H. Von; Precht Noyé, Pernille; Barhoun, A

    2005-01-01

    The redox reactions in KCl-NaCl-NaF-K2TiF6 melts reduced by titanium metal have been studied by cyclic voltammetry and chronopotentiommetry. At platinum and nickel electrodes waves due to alloy formation were seen preceding the Ti(III) --> Ti metal deposition wave. The presence of oxide species...

  14. Quantitative analysis of UV excitation bands for red emissions in Pr3+-doped CaTiO3, SrTiO3 and BaTiO3 phosphors by peak fitting

    International Nuclear Information System (INIS)

    Fujiwara, Rei; Sano, Hiroyuki; Shimizu, Mikio; Kuwabara, Makoto

    2009-01-01

    A quantitative spectral analysis of the ultraviolet (UV) broad excitation bands, which are located in the range 300-400 nm, for red emissions at around 610 nm in Pr-doped CaTiO 3 , SrTiO 3 :Al and BaTiO 3 :Mg phosphors has been carried out using a peak fitting technique. The obtained results demonstrate that the UV broad band of CaTiO 3 :Pr consists of four primary excitation bands centered around 330, 335, 365 and 380 nm and those of both SrTiO 3 :Al and BaTiO 3 :Mg consist of three primary bands centered around 310, 345 and 370 nm. Based on the behavior patterns and the values of the respective primary excitation bands' parameters, i.e. center gravity (λ top ), maximum height (I max ) and full-width at half-maximum (FWHM), the UV-to-red relaxation processes in these titanate phosphors can be explained to be essentially the same, except for the existence of an additional relaxation pathway via electron-trap states in CaTiO 3 :Pr, which gives a characteristic shape of its UV excitation spectrum in the wavelength range of >360 nm

  15. Tilapia lake virus (TiLV): Literature review

    OpenAIRE

    Jansen, Mona Dverdal; Mohan, Chadag Vishnumurthy

    2017-01-01

    Tilapia lake virus (TiLV) is an emerging infectious agent that has recently been identified in diseased tilapia on three continents. At the time of writing, scientific publications have reported TiLV in samples collected from Colombia, Ecuador, Egypt, Israel and Thailand. While the link between TiLV and disease outbreaks in Israel and Thailand are well documented, further investigations are being undertaken to determine the significance of TiLV in the other countries. Israel and Taiwan Provin...

  16. Time-resolved XRD study of TiC-TiB2 composites obtained by SHS

    International Nuclear Information System (INIS)

    Contreras, L.; Turrillas, X.; Vaughan, G.B.M.; Kvick, A.; Rodriguez, M.A.

    2004-01-01

    Composites of TiC and TiB 2 were prepared by self-propagating high-temperature synthesis (SHS). Two routes were attempted; from the elements and from a mixture of anatase, boron oxide, graphite and magnesium. The reactions were monitored in situ by synchrotron X-ray diffraction (λ = 0.26102 A). The powder mixtures were compacted as cylindrical pellets and upon ignition diffraction patterns were collected every 65 ms with a CCD camera. TiC was the first phase to form, followed by TiB 2 . The reactions take place in time scales of 0.1 s. The temperature profile for the first route was established from the peak position and the known thermal expansion coefficients. The microstructure of the final products was different: particles of 10 μm for the first and submicron for the second. The viability of the second route to produce ceramic powders in a cheaper way was confirmed

  17. Spin-polarized electron gas in Co2MSi/SrTiO3(M= Ti, V, Cr, Mn, and Fe) heterostructures

    KAUST Repository

    Nazir, S.

    2016-06-08

    Spin-polarized density functional theory is used to study the TiO2 terminated interfaces between the magnetic Heusler alloys Co2Si (M = Ti, V, Cr, Mn, and Fe) and the non-polar band insulator SrTiO3. The structural relaxation at the interface turns out to depend systematically on the lattice mis- match. Charge transfer from the Heusler alloys (mainly the M 3d orbitals) to the Ti dxy orbitals of the TiO2 interface layer is found to gradually grow from M = Ti to Fe, resulting in an electron gas with increasing density of spin-polarized charge carriers. (© 2016 WILEY-VCH Verlag GmbH &Co. KGaA, Weinheim). © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

  18. The appearance of Ti{sup 3+} states in solution-processed TiO{sub x} buffer layers in inverted organic photovoltaics

    Energy Technology Data Exchange (ETDEWEB)

    Zhidkov, Ivan S.; Kurmaev, Ernst Z.; Kukharenko, Andrey I.; Korotin, Danila M. [M. N. Mikheev Institute of Metal Physics, Russian Academy of Sciences-Ural Branch, S. Kovalevskoi Str. 18, 620990 Yekaterinburg (Russian Federation); Institute of Physics and Technology, Ural Federal University, Mira Str. 19, 620002 Yekaterinburg (Russian Federation); McLeod, John A., E-mail: jmcleod@suda.edu.cn [Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, 199 Ren' ai Road, Suzhou, 215123, Jiangsu (China); Korotin, Michael A. [M. N. Mikheev Institute of Metal Physics, Russian Academy of Sciences-Ural Branch, S. Kovalevskoi Str. 18, 620990 Yekaterinburg (Russian Federation); Savva, Achilleas; Choulis, Stelios A. [Molecular Electronics and Photonics Research Unit, Department of Mechanical Engineering and Materials Science and Engineering, Cyprus University of Technology, Kitiou Kiprianou Str. 45, 3603 Limassol (Cyprus); Cholakh, Seif O. [Institute of Physics and Technology, Ural Federal University, Mira Str. 19, 620002 Yekaterinburg (Russian Federation)

    2016-07-11

    We study the low-temperature solution processed TiO{sub x} films and device structures using core level and valence X-ray photoelectron spectroscopy (XPS) and electronic structure calculations. We are able to correlate the fraction of Ti{sup 3+} present as obtained from Ti 2p core level XPS with the intensity of the defect states that appear within the band gap as observed with our valence XPS. Constructing an operating inverted organic photovoltaic (OPV) using the TiO{sub x} film as an electron selective contact may increase the fraction of Ti{sup 3+} present. We provide evidence that the number of charge carriers in TiO{sub x} can be significantly varied and this might influence the performance of inverted OPVs.

  19. Growth feature of ionic nitrogen doped CN_x bilayer films with Ti and TiN interlayer by pulse cathode arc discharge

    International Nuclear Information System (INIS)

    Zhou, Bing; Liu, Zhubo; Piliptsou, D.G.; Rogachev, A.V.; Yu, Shengwang; Wu, Yanxia; Tang, Bin; Rudenkov, A.S.

    2016-01-01

    Graphical abstract: - Highlights: • Ti/ and TiN/CN_x (N"+) bilayers are prepared at various frequencies by pulse cathode arc. • Ti interlayer facilitates the introduction of N atoms into the CN_x (N"+) films. • The most N-sp"2C bonds (mainly graphite-like N) present in the TiN/CN_x (N"+, 3 Hz) film. • Ti/CN_x (N"+, 3 Hz) bilayer possesses small size and disordering of Csp"2 clusters. • The higher hardness and the lower stress presents in the TiN/CN_x (N"+, 10 Hz) bilayer. - Abstract: Using nano-scaled Ti and TiN as interlayer, ionic nitrogen doped carbon (CN_x (N"+)) bilayer films were prepared at various pulse frequencies by cathode arc technique. Elemental distribution at the interface, bonding compositions, microstructure, and mechanical properties of CN_x (N"+) bilayer films were investigated in dependence of interlayer and pulse frequency by Auger electron spectroscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, nanoindentation, and surface profilometer. The results showed that the diffusion extent of C atoms at the interface of CN_x (N"+) bilayers is higher than for the α-C and CN_x (N_2) bilayers with the same interlayer. Nitrogen atoms could diffuse throughout the pre-deposited Ti and TiN layers into the Si substrate for all CN_x (N"+) bilayers. Ti interlayer facilitates the introduction of N atoms into the CN_x (N"+) films and exhibits a certain catalytic effect on the coordination of N atoms with sp"2- and sp"3-C binding. More nitrogenated and intense CN bonding configurations (mainly graphite-like N) form in the TiN/CN_x (N"+) bilayer. Ti/CN_x (N"+) bilayer prepared at low frequency possesses small size and disordering of Csp"2 clusters but TiN interlayer weakens the formation of Csp"2 bonding and increases the disordering of Csp"2 clusters in the films. The residual stress in the bilayer is lower than for CN_x (N"+) monolayer. The higher hardness and the lower residual stress are present in the TiN/CN_x (N"+, 10 Hz) bilayer.

  20. Preparation and characterization of Sr-Ti-hardystonite (Sr-Ti-HT nanocomposite for bone repair application

    Directory of Open Access Journals (Sweden)

    Hossein Mohammadi

    2015-07-01

    Full Text Available Objective(s: Hardystonite (HT is Zn-modified silicate bioceramics with promising results for bone tissue regeneration. However, HT possesses no obvious apatite formation. Thus, in this study we incorporated Sr and Ti into HT to prepare Sr-Ti-hardystonite (Sr-Ti-HT nanocomposite and evaluated its in vitro bioactivity with the purpose of developing a more bioactive bone substitute material. Materials and methods:The HT and Sr-Ti-HT were prepared by mechanical milling and subsequent heat treatment. Calcium oxide (CaO, zinc oxide (ZnO and silicon dioxide (SiO2 (all from Merck were mixed with molar ratio of 2:1:2. The mixture of powders mixture was then milled in a planetary ball mill for 20 h. In the milling run, the ball-to-powder weight ratio was 10:1 and the rotational speed was 200 rpm. After synthesis of HT, 3% nanotitanium dioxide (TiO2, Degussa and 3% strontium carbonate (SrCO3, Merck were added to HT and then the mixture was ball milled and calcined at 1150°C for 6 h. Simultaneous thermal analysis (STA, X-ray diffraction (XRD, Transmission electron microscopy (TEM and Fourier transform infra-red spectroscopy (FT-IR performed to characterize the powders. Results:XRD and FT-IR confirmed the crystal phase and silicate structure of HT and TEM images demonstrated the nanostructure of powders. Further, Sr-Ti-HT induced apatite formation and showed a higher human mesenchymal stem cell (hMSCs adhesion and proliferation compared to HT. Conclusion:Our study revealed that Sr-Ti-HT with a nanostructured crystal structure of 50 nm, can be prepared by mechanical activation to use as biomaterials for orthopedic applications.

  1. Fabrication of TiO{sub 2} nanorod assembly grafted rGO (rGO@TiO{sub 2}-NR) hybridized flake-like photocatalyst

    Energy Technology Data Exchange (ETDEWEB)

    Lv, Kangle, E-mail: lvkangle@mail.scuec.edu.cn [Department of Science and Environmental Studies, The Hong Kong Institute of Education, Taipo, N.T., Hong Kong (China); Key Laboratory of Catalysis and Materials Science of the State Ethnic Affairs Commission and Ministry of Education, College of Resources and Environmental Science, South-Central University for Nationalities, Wuhan 430074 (China); Fang, Shun; Si, Lingling; Xia, Yang [Key Laboratory of Catalysis and Materials Science of the State Ethnic Affairs Commission and Ministry of Education, College of Resources and Environmental Science, South-Central University for Nationalities, Wuhan 430074 (China); Ho, Wingkei, E-mail: keithho@ied.edu.hk [Department of Science and Environmental Studies, The Hong Kong Institute of Education, Taipo, N.T., Hong Kong (China); Li, Mei [Key Laboratory of Catalysis and Materials Science of the State Ethnic Affairs Commission and Ministry of Education, College of Resources and Environmental Science, South-Central University for Nationalities, Wuhan 430074 (China)

    2017-01-01

    Highlights: • TiO{sub 2} nanorod assembly grafted with GO hybrid was successfully fabricated. • TiO{sub 2} nanorods can reduce the aggregation of TiO{sub 2} nanoparticles on graphene. • This unique structure facilitates the injection of electron from TiO{sub 2} to graphene. - Abstract: To efficiently separate the photo-generated electron–hole pairs of TiO{sub 2} hybrid, anatase TiO{sub 2} nanorod assembly grafted reduced graphene oxides (rGO@TiO{sub 2}-NR) hybrid was successfully fabricated using potassium titanium oxalate (PTO) and graphene oxides (GO) as starting materials and diethylene glycol (DEG) as reductant. The effect of GO content on the structure and photocatalytic activity of rGO@TiO{sub 2}-NR composite was systematically studied. Results show that, in the absence of GO, only TiO{sub 2} microsphere assembly is obtained from TiO{sub 2} nanorods. The presence of GO results in the formation of a flake-like TiO{sub 2}-nanorod-assembled grafted rGO hybrid. The photocatalytic activity of rGO@TiO{sub 2}-NR composite increases first and then decreases with increase in the amount of GO from 0 wt.% to 10 wt.%. The hybridized S4 sample prepared with 4 wt.% GO possesses the highest photocatalytic activity with a constant rate of 0.039 min{sup −1} in the photocataytic degradation of Brilliant X-3B dye (X3B); this sample was enhanced more than three times when compared with pure TiO{sub 2} sample (0.012 min{sup −1}). The enhanced photocatalytic activity of the rGO@TiO{sub 2}-NR hybrid was attributed to the strong interaction between TiO{sub 2} nanorods and rGO. The unique hierarchical structure of 1D nanorod assembly TiO{sub 2}–rGO flakes facilitates the injection and transfer of photo-generated electrons from TiO{sub 2} to graphene, thus retarding the recombination of electron–hole pairs and enhancing the photocatalytic activity. The enlarged BET surface areas, not only increasing the number of active sites, but also facilitating the adsorption of

  2. Studies of U-Pu-C-Ti compounds

    International Nuclear Information System (INIS)

    Milet, C.

    1967-01-01

    The U-Pu-C-Ti compounds (5 to 20 atoms per cent Ti) have been studied in order to improve some properties of U-Pu-C carbides and to extend the existence field of the (U, Pu) C phase. The Pu/(U+Pu) ratio has been fixed to 15 per cent. All the alloys were elaborated and cast in an arc furnace. A two-phases field (U, Pu) C + Ti C exists which permits to avoid di- and sesqui-carbides and the (U, Pu) phase. An eutectic between (U, Pu) C and Ti C was found around 15 atoms per cent Ti. Practically the whole of the titanium is in Ti C form, titanium solubility in (U, Pu) C being inferior to 1 atom per cent. The most promising alloy are those containing two phases: (U, Pu) C+ Ti C. In comparison with the (U, Pu) C phase, titanium addition does not change very much the thermal expansion coefficients nor the thermal cycling behaviour between 160 and 1000 Celsius degrees which is excellent. On the other hand atmospheric corrosion behaviour is improved; compatibility with stainless steel is better; thermal conductivity, calculated from electrical resistivity K is enhanced: for U(0.85)-Pu(0.15)-C alloy we have K 0.179 W/cm.C at 1000 C and K = 0.187 W/cm.C at 1500 C, for U-Pu-C-Ti (10 atoms % Ti) alloy we have K = 0.193 W/cm.C at 1000 C and K = 0.205 W/cm.C at 1500 C. (author) [fr

  3. Early Cretaceous high-Ti and low-Ti mafic magmatism in Southeastern Tibet: Insights into magmatic evolution of the Comei Large Igneous Province

    Science.gov (United States)

    Wang, Yaying; Zeng, Lingsen; Asimow, Paul D.; Gao, Li-E.; Ma, Chi; Antoshechkina, Paula M.; Guo, Chunli; Hou, Kejun; Tang, Suohan

    2018-01-01

    The Dala diabase intrusion, at the southeastern margin of the Yardoi gneiss dome, is located within the outcrop area of the 132 Ma Comei Large Igneous Province (LIP), the result of initial activity of the Kerguelen plume. We present new zircon U-Pb geochronology results to show that the Dala diabase was emplaced at 132 Ma and geochemical data (whole-rock element and Sr-Nd isotope ratios, zircon Hf isotopes and Fe-Ti oxide mineral chemistry) to confirm that the Dala diabase intrusion is part of the Comei LIP. The Dala diabase can be divided into a high-Mg/low-Ti series and a low-Mg/high-Ti series. The high-Mg/low-Ti series represents more primitive mafic magma compositions that we demonstrate are parental to the low-Mg/high-Ti series. Fractionation of olivine and clinopyroxene, followed by plagioclase within the low-Mg series, lead to systematic changes in concentrations of mantle compatible elements (Cr, Co, Ni, and V), REEs, HFSEs, and major elements such as Ti and P. Some Dala samples from the low-Mg/high-Ti series contain large ilmenite clusters and show extreme enrichment of Ti with elevated Ti/Y ratios, likely due to settling and accumulation of ilmenite during the magma chamber evolution. However, most samples from throughout the Comei LIP follow the Ti-evolution trend of the typical liquid line of descent (LLD) of primary OIB compositions, showing strong evidence of control of Ti contents by differentiation processes. In many other localities, however, primitive magmas are absent and observed Ti contents of evolved magmas cannot be quantitatively related to source processes. Careful examination of the petrogenetic relationship between co-existing low-Ti and high-Ti mafic rocks is essential to using observed rock chemistry to infer source composition, location, and degree of melting.

  4. Characterization of Al-Ti phases in cycled TiF{sub 3}-enhanced Na{sub 2}LiAlH{sub 6}

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Y. [Department of Physics, Institute for Energy Technology, P.O. Box 40, NO-2027 Kjeller (Norway)]. E-mail: yumikon@ife.no; Fossdal, A. [Department of Physics, Institute for Energy Technology, P.O. Box 40, NO-2027 Kjeller (Norway); Brinks, H.W. [Department of Physics, Institute for Energy Technology, P.O. Box 40, NO-2027 Kjeller (Norway); Hauback, B.C. [Department of Physics, Institute for Energy Technology, P.O. Box 40, NO-2027 Kjeller (Norway)

    2006-06-08

    TiF{sub 3}-enhanced Na{sub 2}LiAlH{sub 6} was investigated after dehydrogenation-hydrogenation cycles by synchrotron X-ray diffraction. There was no sign of Ti after ball-milling with TiF{sub 3}, but two types of Al-Ti phases were observed in the cycled samples. In a sample after measuring five pressure-composition isotherms in the temperature range from 170 to 250 deg. C, a fcc phase with a = 3.987 A was observed. This phase is considered to be Al{sub 3}Ti with the L1{sub 2} structure. Samples after one or four cycles at selected temperatures between 170 and 250 deg. C showed diffraction from another fcc phase with a {approx} 4.03 A. This indicates formation of an Al{sub 1-y}Ti {sub y} solid-solution phase with y {approx} 0.15 similar to previously reported for cycled NaAlH{sub 4} with Ti additives.

  5. A Pt/TiO(2)/Ti Schottky-type selection diode for alleviating the sneak current in resistance switching memory arrays.

    Science.gov (United States)

    Park, Woo Young; Kim, Gun Hwan; Seok, Jun Yeong; Kim, Kyung Min; Song, Seul Ji; Lee, Min Hwan; Hwang, Cheol Seong

    2010-05-14

    This study examined the properties of Schottky-type diodes composed of Pt/TiO(2)/Ti, where the Pt/TiO(2) and TiO(2)/Ti junctions correspond to the blocking and ohmic contacts, respectively, as the selection device for a resistive switching cross-bar array. An extremely high forward-to-reverse current ratio of approximately 10(9) was achieved at 1 V when the TiO(2) film thickness was 19 nm. TiO(2) film was grown by atomic layer deposition at a substrate temperature of 250 degrees C. Conductive atomic force microscopy revealed that the forward current flew locally, which limits the maximum forward current density to current measurement showed a local forward current density as high as approximately 10(5) A cm(-2). Therefore, it is expected that this type of Schottky diode effectively suppresses the sneak current without adverse interference effects in a nano-scale resistive switching cross-bar array with high block density.

  6. Stability and dewetting kinetics of thin gold films on Ti, TiOx and ZnO adhesion layers

    International Nuclear Information System (INIS)

    Schaefer, Brian T.; Cheung, Jeffrey; Ihlefeld, Jon F.; Jones, Jacob L.; Nagarajan, Valanoor

    2013-01-01

    We present an in situ high-temperature confocal laser microscopy study on the thermal stability of 40 nm thick gold thin films grown on 40 nm Ti, TiO x and ZnO adhesion layers on (0 0 1) Si. In situ observation of the dewetting process was performed over a wide range of set temperatures (400–800 °C) and ramp rates (10–50 °C min −1 ) for each gold/adhesion layer combination. We found that significant dewetting and subsequent formation of gold islands occurs only at and above 700 °C for all adhesion layers. The dewetting is driven to equilibrium for gold/ZnO compared to gold/Ti and gold/TiO x as confirmed by ex situ X-ray diffraction and scanning electron microscopy characterization. Quantification of the in situ data through stretched exponential kinetic models reveals an underlying apparent activation energy of the dewetting process. This energy barrier for dewetting is higher for gold/Ti and gold/TiO x compared to gold/ZnO, thus confirming the ex situ observations. We rationalize that these apparent activation energies correspond to the underlying thermal stability of each gold/adhesion layer system

  7. Enhanced Optical and Electrical Properties of TiO_2 Buffered IGZO/TiO_2 Bi-Layered Films

    International Nuclear Information System (INIS)

    Moon, Hyun-Joo; Kim, Daeil

    2016-01-01

    In and Ga doped ZnO (IGZO, 100-nm thick) thin films were deposited by radio frequency magnetron sputtering without intentional substrate heating on a bare glass substrate and a TiO_2-deposited glass substrate to determine the effect of the thickness of a thin TiO_2 buffer layer on the structural, optical, and electrical properties of the films. The thicknesses of the TiO_2 buffer layers were 5, 10 and 15 nm, respectively. As-deposited IGZO films with a 10 nm-thick TiO_2 buffer layer had an average optical transmittance of 85.0% with lower resistivity (1.83×10-2 Ω cm) than that of IGZO single layer films. The figure of merit (FOM) reached a maximum of 1.44×10-4 Ω-1 for IGZO/10 nm-thick TiO_2 bi-layered films, which is higher than the FOM of 6.85×10-5 Ω-1 for IGZO single layer films. Because a higher FOM value indicates better quality transparent conducting oxide (TCO) films, the IGZO/10 nm-thick TiO_2 bi-layered films are likely to perform better in TCO applications than IGZO single layer films.

  8. TiC growth in C fiber/Ti alloy composites during liquid infiltration

    Science.gov (United States)

    Warrier, S. G.; Lin, R. Y.

    1993-01-01

    A cylindrical model is developed for predicting the reaction zone thickness of carbon fiber-reinforced Ti-matrix composites, and good agreement is obtained between its predicted values and experimental results. The reaction-rate constant for TiC formation is estimated to be 1.5 x 10 exp -9 sq cm/sec. The model is extended to evaluate the relationship between C-coating thicknesses on SiC fibers and processing times.

  9. Remelting of aluminium with the addition of AlTi5B1 and AlTi3C0,15 grain refiners

    Directory of Open Access Journals (Sweden)

    Dobešrek, M.

    2008-04-01

    Full Text Available It was found that concentration of boron in aluminium with the addition of AlTi5B1 grain refiner is decreasing during remelting as a consequence of TiB2 particles settling down due to gravity. TiB2 particles remained in aluminium after four remelts shows lower effect of grain refinement compared to non-remelted samples with the same TiB2 content. It was also found that TiC particles are still present in aluminium with the addition of AlTi3C0,15 grain refiner after four remelts and they probably participate in nucleation of α-Al grains.

  10. Elevated temperature characterization of electron beam freeform fabricated Ti-6Al-4V and dispersion strengthened Ti-8Al-1Er

    Energy Technology Data Exchange (ETDEWEB)

    Bush, R.W., E-mail: ralph.bush@usafa.edu [Department of Engineering Mechanics, 2354 Fairchild Dr., U.S. Air Force Academy, USAF Academy, CO 80840 (United States); Brice, C.A. [Lockheed Martin Aeronautics Co., Fort Worth, TX (United States)

    2012-09-30

    Highlights: Black-Right-Pointing-Pointer Electron beam freeform fabrication process. Black-Right-Pointing-Pointer Ti-6Al-4V and rare-earth dispersion Ti alloy. Black-Right-Pointing-Pointer Tensile, creep, and oxidation properties comparable to alloys made with conventional fabrication methods. Black-Right-Pointing-Pointer Fabrication process allows use of rare-earth dispersion Ti alloy. - Abstract: Electron beam freeform fabrication is an additive manufacturing process that can be used to build fully dense, structural metallic parts directly from a three-dimensional computer model. This technique can replace conventional fabrication methods, such as forging or machining from plate, and enable significant cost, time, and tool savings. Additionally, this method enables the fabrication of alloys with novel compositions that are not well suited to production via ingot metallurgy processes. Ti-8Al-1Er is an experimental dispersion strengthened titanium alloy composition that requires rapid cooling to achieve optimal properties and thus is not amenable to ingot metallurgy production methods. Oxide dispersion strengthened alloys, such as Ti-8Al-1Er are known to have excellent thermal stability and improved high temperature properties. In this work, the room temperature tensile, elevated temperature tensile, creep properties and oxidation resistance of electron beam additive manufactured Ti-6Al-4V and Ti-8Al-1Er were measured and compared to those of laser beam additive manufactured Ti-8Al-1Er and wrought Ti-6Al-4V. Elevated temperature tensile properties were measured between 93 Degree-Sign and 538 Degree-Sign C. Creep tests were performed between 425 Degree-Sign and 455 Degree-Sign C at stresses between 345 and 483 MPa. It was found that the elevated temperature properties of the electron beam additive manufactured products are comparable to those of wrought forms. The elevated temperature strengths of Ti-8Al-1Er are comparable to those of Ti-6Al-4V in percentage of room

  11. TiO2-ITO and TiO2-ZnO nanocomposites: application on water treatment

    Directory of Open Access Journals (Sweden)

    Bessais B.

    2012-06-01

    Full Text Available One of the most promising ideas to enhance the photocatalytic efficiency of the TiO2 is to couple this photocatalyst with other semiconductors. In this work, we report on the development of photo-catalytic properties of two types of composites based on TiO2 – ITO (Indium Tin Oxide and TiO2 – ZnO deposited on conventional ceramic substrates. The samples were characterized by X-ray diffraction (XRD and transmission Electron Microscopy (TEM. The photo-catalytic test was carried out under UV light in order to reduce/oxidize a typical textile dye (Cibacron Yellow. The experiment was carried out in a bench scale reactor using a solution having a known initial dye concentration. After optimization, we found that both nanocomposites exhibit better photocatalytic activity compared to the standard photocatalyst P25 TiO2.

  12. RBS study of Ti/ZnO interface

    International Nuclear Information System (INIS)

    Rahman, A.M.A.; Narusawa, T.

    2008-01-01

    We have studied the interface stability of the Ti(overlayer)/ZnO(substrate) system. Ti thin film was grown on the Zn face of single crystal ZnO(0 0 0 1) substrate by the vacuum deposition technique. The Ti film thickness was typically 16 nm. Then the samples were annealed in air at 300 and 400 deg. C for 15 min, respectively. The deposition and annealing effects on the interface structure were investigated with Rutherford backscattering and channeling spectroscopy using 2 MeV He + ion beam. After Ti deposition the minimum yield from the ZnO substrate increased from 2% to 7%. This suggests severe damage caused by deposition, i.e. the interface reaction between Ti and ZnO (even at room temperature). A significant amount of Zn (approximately 6.4 x 10 16 atoms/cm 2 ) moved onto the surface after post-annealing at 400 deg. C. Since Ti has a stronger tendency to react with O than Zn, it is expected that Ti reacts with substrate oxygen leaving behind free Zn atoms, which can easily migrate onto the surface. We discuss how the Ti/ZnO interface reaction in detail, and seek to find another good metallic contact for ZnO devices, which are attracting much attention recently for practical applications as well as scientific aspects

  13. Photocatalytic activity of bipolar pulsed magnetron sputter deposited TiO{sub 2}/TiWO{sub x} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Weng, Ko-Wei; Hu, Chung-Hsuan; Hua, Li-Yu; Lee, Chin-Tan [Department of Electronic Engineering, National Quemoy University, 1 Daxue Road, Jinning Township, Kinmen 89250, Taiwan, ROC (China); Zhao, Yu-Xiang [Department of Computer Science and Information Engineering, National Quemoy University, Taiwan, ROC (China); Chang, Julian; Yang, Shu-Yi [Department of Applied English, National Quemoy University, Taiwan, ROC (China); Han, Sheng, E-mail: shenghan@nutc.edu.tw [Center for General Education, National Taichung University of Science and Technology, 129 San-min Road, Section 3, Taichung 40401, Taiwan, ROC (China)

    2016-08-15

    Highlights: • TiO{sub 2}/TiWO{sub x} films were fabricated by a bipolar pulsed magnetron sputtering apparatus. • Titanium oxide being sputtered tungsten enhanced the highly oriented of TiO{sub 2} (1 0 1) plane of the specimen assemblies. • The mechanism WO{sub 3}(h{sup +}, e{sup −})/TiO{sub 2}(h{sup +}, e{sup −}) → WO{sub 3}(e{sup −})/TiO{sub 2}(h{sup +}) shows the higher hydrophilicity and lower contact angle. - Abstract: Titanium oxide films were formed by sputtering and then TiWO{sub x} films were deposited by bipolar pulsed magnetron sputtering with pure titanium and tungsten metal targets. The sputtering of titanium oxide with tungsten enhanced the orientation of the TiO{sub 2} (1 0 1) plane of the specimen assemblies. The main varying parameter was the tungsten pulse power. Titanium oxide sputtered with tungsten using a pulsing power of 50 W exhibited a superior hydrophilic property, and a contact angle of 13.1°. This fabrication conditions maximized the photocatalytic decomposition of methylene blue solution. The mechanism by which the titanium oxide was sputtered with tungsten involves the photogeneration of holes and electron traps, inhibiting the hole–electron recombination, enhancing hydrophilicity and reducing the contact angle.

  14. Surface characterizations of TiH{sub 2} powders before and after dehydrogenation

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yeguang [School of Aeronautics & Astronautics, Sichuan University, Chengdu, 610065 (China); Wang, Chunming; Liu, Yang; Liu, Shaopeng; Xiao, Sufen [College of Materials Science and Engineering, Sichuan University, Chengdu, 610065 (China); Chen, Yungui, E-mail: ygchen60@aliyun.com [School of Aeronautics & Astronautics, Sichuan University, Chengdu, 610065 (China); College of Materials Science and Engineering, Sichuan University, Chengdu, 610065 (China)

    2017-07-15

    Highlights: • Oxides characteristics of TiH{sub 2} and HDH-Ti are investigated by XPS depth profiles. • The relative contents of TiO{sub 2}, Ti{sub 2}O{sub 3} and TiO are lower after dehydrogenation. • The decrease of Ti{sub 2}O{sub 3} is more remarkable followed by TiO{sub 2}, TiO after dehydrogenation. • The H atoms of TiH{sub 2} react preferentially with Ti{sub 2}O{sub 3} followed by TiO{sub 2}, TiO. - Abstract: The oxide film of TiH{sub 2} and HDH-Ti powder are investigated using X-ray photoelectron spectroscopy (XPS). The XPS depth profiles indicate that there exists mainly Ti{sup 2+}, Ti{sup 3+}, Ti{sup 4+} and Ti{sup 0} on TiH{sub 2} and HDH-Ti surface. The intensities of Ti 2p decrease for Ti{sup 4+}, first increase and then decrease for Ti{sup 3+} and Ti{sup 2+}, and increase all the time for Ti{sup 0} in the surface layer of TiH{sub 2} and HDH-Ti with the sputtering depth increasing. The relative fractions of TiO{sub 2}, Ti{sub 2}O{sub 3} and TiO for the Ti 2p of TiH{sub 2} and HDH-Ti first decrease and then slow down with the sputtering depth increasing. Meanwhile, the relative fractions of TiO{sub 2} and TiO of HDH-Ti are lower than that of TiH{sub 2} after the sputtering depth of about 5 nm, and the fraction of Ti{sub 2}O{sub 3} of HDH-Ti is always lower that of TiH{sub 2}. In addition, the decrease of Ti{sub 2}O{sub 3} is much pronounced, followed by TiO{sub 2} and TiO before and after dehydrogenation when the sputtering depth is more than 5 nm. The XPS depth profiles and calculation results suggest that the release of H atoms removes the part of oxygen on TiH{sub 2} surface, which results in the thinner oxide layer and low oxygen content of HDH-Ti powder.

  15. Magnetocrystalline anisotropy and magnetic domain structure of ErFe11Ti and HoFe11Ti compounds

    International Nuclear Information System (INIS)

    Pastushenkov, Yury G.; Skokov, Konstantin P.; Skourski, Yury; Lebedeva, Ludmila; Ivanova, Tatyana; Grushichev, Anton; Mueller, Karl-Hartmut

    2006-01-01

    Tetragonal ThMn 12 -type single crystalline ErFe 11 Ti and HoFe 11 Ti samples have been investigated by magnetization measurements and by observations of the magnetic domain structure at various temperatures between 10 and 300K. The magnetic structure of ErFe 11 Ti changes from room temperature 'easy axis' (c-axis) type to conical at spin-reorientation temperature T SR =50K. The HoFe 11 Ti has a metastable anisotropy energy minimum in the a-direction at T<40K. It leads to a first-order magnetization process detected by magnetization measurements along the a-axis in this temperature region

  16. Analysis of the hydrogen permeation properties of TiN-TiC bilayers deposited on martensitic stainless steel

    International Nuclear Information System (INIS)

    Checchetto, R.; Horino, Y.; Benamati, G.

    1996-01-01

    The efficiency of TiN-TiC bilayer coatings, deposited by ion-beam-assisted deposition on martensitic steel, as a hydrogen permeation barrier was investigated by a gas phase method; the hydrogen permeability in the TiN-TiC bilayers is very low, at least 10 4 times lower than in the steel substrate in the temperature interval 470-570 K. Possible physical mechanisms, responsible for the reduced permeability of the ceramic bilayers, are discussed. In particular, from our experimental results, it can be concluded that chemisorption and/or hydrogen jumping from surface sites to the first subsurface atomic layer represents the hydrogen permeation limiting process. (orig.)

  17. A pH sensor based on the TiO{sub 2} nanotube array modified Ti electrode

    Energy Technology Data Exchange (ETDEWEB)

    Zhao Rongrong; Xu Meizhu [Ministry of Education Key Laboratory of Analysis and Detection for Food Safety, Fujian Provincial Key Laboratory of Analysis and Detection for Food Safety, Department of Chemistry, Fuzhou University, 523 Gongye Road, Fuzhou 350002, Fujian (China); Wang Jian, E-mail: jwang@fzu.edu.c [Ministry of Education Key Laboratory of Analysis and Detection for Food Safety, Fujian Provincial Key Laboratory of Analysis and Detection for Food Safety, Department of Chemistry, Fuzhou University, 523 Gongye Road, Fuzhou 350002, Fujian (China); Chen Guonan, E-mail: guonanchen@126.co [Ministry of Education Key Laboratory of Analysis and Detection for Food Safety, Fujian Provincial Key Laboratory of Analysis and Detection for Food Safety, Department of Chemistry, Fuzhou University, 523 Gongye Road, Fuzhou 350002, Fujian (China)

    2010-08-01

    In this paper, a novel solid state pH sensor was fabricated by anodization of titanium substrate electrode. The relationship between pH sensitivity and hydrophilicity or surface morphology of TiO{sub 2} film was investigated. Amorphous TiO{sub 2} nanotube has better pH response than anatase TiO{sub 2} nanotube. After being irradiated by ultraviolet light (UV), the potential response of the electrode modified by amorphous TiO{sub 2} nanotube was close to Nernst equation (59 mV/pH). SEM, XRD, and XPS were used to characterize electrodes. Possible mechanism was discussed by analyzing surface hydroxyl groups, crystal structure and hydrophilicity of the electrodes. The electrode has been used to detect some kinds of soft drinks and shows good response.

  18. Stability of Zn–Ni–TiO2 and Zn–TiO2 nanocomposite coatings in near-neutral sulphate solutions

    International Nuclear Information System (INIS)

    Gomes, A.; Almeida, I.; Frade, T.; Tavares, A. C.

    2012-01-01

    Zn–Ni–TiO 2 and Zn–TiO 2 nanocomposites were prepared by galvanostatic cathodic square wave deposition. X-ray diffraction analysis and scanning electron microscopy revealed that the occlusion of TiO 2 nanoparticles (spherical shaped with diameter between 19.5 and 24.2 nm) promotes the formation of the γ-Ni 5 Zn 21 phase, changes the preferred crystallographic orientation of Zn from (101) and (102) planes to (002), and decreases the particle size of the metallic matrices. The stability of the nanocomposites immersed in near-neutral 0.05 mold m −3 Na 2 SO 4 solution (pH 6.2) was investigated over 24 h. The initial open circuit potential for the Zn–Ni–TiO 2 and Zn–TiO 2 coatings were −1.32 and −1.51 V (vs. Hg/Hg 2 SO 4 ), respectively, and changed to −1.10 and –1.49 V (vs. Hg/Hg 2 SO 4 ) after 24 h of immersion. Data extracted from the steady state polarization curves demonstrated that the metal–TiO 2 nanocomposites have, with respect to the metal coatings, a higher corrosion potential in the case of the Zn–Ni alloy composite; a lower corrosion potential in the case of Zn-based nanocomposite albeit the predominant (002) crystallographic orientation; and a lower initial corrosion resistance due to the smaller grain size and higher porosity in the Zn–Ni–TiO 2 and Zn–TiO 2 nanocomposites. Morphological and chemical analyses showed that a thicker passive layer is formed on the surface of the Zn–Ni–TiO 2 and Zn–TiO 2 deposits. After 24 h of immersion in the sulphate solution, the Zn–Ni–TiO 2 coating has the highest corrosion stability due to the double-protective action created by the deposit’s surface enrichment in Ni plus the higher amount of corrosion products.

  19. ZrC zone structure and features of electronic structure of solid solutions on the base ZrC, ZrN, TiC and TiN

    International Nuclear Information System (INIS)

    Mokhracheva, L.P.; Gel'd, P.V.; Tskhaj, V.A.

    1983-01-01

    The results of ZrC zone structure calculation conducted using the strong bond method in the three-centre variant are given. Essentially higher degree of M-C chemical bond ionicity than in TiC is shown to take place for it. Solid solution formation in TiC-ZrC, TiN-ZrC and ZrC-ZrN systems differing from TiC-TiN, TiN-ZrN and TiC-TiN is stated to be followed by essential deformation of component zone structures that, obviously, should prevent formation of solid solutions without vacancies in sublatices in these systems

  20. Structure and properties of selected cemented carbides and cermets covered with TiN/(Ti,Al,SiN/TiN coatings obtained by the cathodic arc evaporation process

    Directory of Open Access Journals (Sweden)

    Leszek A. Dobrzañski

    2005-06-01

    Full Text Available This study presents the results of microstructural examinations, mechanical tests and service performance tests carried out on thin TiN/(Ti,Al,SiN/TiN wear resistance coatings obtained by the CAE process on cermet and cemented carbide substrates. Microstructural examinations of the applied coatings and the substrate were made with an OPTON DSM 940 SEM and a LEICA MEF4A light microscope. Adhesion of the coatings on cemented carbides and cermets was measured using the scratch test. The cutting properties of the materials were determined from service tests in which continuous machining of C45E steel was carried out. The hardness of the substrate and the microhardness of the coatings were determined with a DUH 202 SHIMADZU ultra microhardness tester with a load of 70 mN. Roughness tests were also carried out before applying the coatings and after the PVD process. Cutting tests confirmed the advantages of the TiN/(Ti,Al,SiN/TiN type coatings obtained using the PVD method in the CAE mode on cemented carbides and cermets, as a material that undergoes very low abrasive, thermal and adhesion wear. These coatings extend tool life compared to commercially available uncoated tools with single and multi-layer coatings deposited using PVD/CVD methods.

  1. A facile method to synthesize nitrogen and fluorine co-doped TiO2 nanoparticles by pyrolysis of (NH4)2TiF6

    International Nuclear Information System (INIS)

    Chen Daimei; Jiang Zhongyi; Geng Jiaqing; Zhu Juhong; Yang Dong

    2009-01-01

    The nitrogen and fluorine co-doped TiO 2 (N-F-TiO 2 ) nanoparticles of anatase crystalline structure were prepared by a facile method of (NH 4 ) 2 TiF 6 pyrolysis, and characterized by thermogravimetry-differential thermal analysis (TG-DTA), X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and ultraviolet visible (UV-Vis) spectroscopy etc. With the increase of calcination temperature, (NH 4 ) 2 TiF 6 decomposed into TiOF 2 and NH 4 TiOF 3 at first, and then formed anatase-type TiO 2 with thin sheet morphology. H 3 BO 3 as oxygen source can promote the formation of anatase TiO 2 , but decrease the F content in the N-F-TiO 2 materials due to the formation of volatile BF 3 during the precursor decomposition. The photocatalytic activity of the obtained N-F-TiO 2 samples was evaluated by the methylene blue degradation under visible light, and all the samples exhibited much higher photocatalytic activity than P25. Moreover, the merits and disadvantages of this proposed method to prepare doped TiO 2 are discussed.

  2. Photocatalytic degradation of vegetable oil floating on water by CoPcS/TiO2/beads and TiO2/beads%CoPcS/TiO2/beads及TiO2/beads光催化降解水面漂浮植物油

    Institute of Scientific and Technical Information of China (English)

    张晓叶; 闫永胜; 孔峰; 王赟

    2007-01-01

    以钛酸四丁酯为原料,以空心玻璃微珠为载体,采用溶胶-凝胶法制备出TiO2/beads光催化剂,用浸渍法制备出CoPcS/TiO2/beads光催化剂.研究了TiO2/beads及CoPcS/TiO2/beads光催化降解水面漂浮植物油的最优条件.结果表明,酸性或中性条件下,375 W中压汞灯照射2~3 h,TiO2/beads与CoPcS/TiO2/beads的投加量分别为3 g与1 g时,植物油的去除率达90%以上,投加微量的H2O2,可大大提高两者的光催化去除率.

  3. Behavior and effect of Ti2Ni phase during processing of NiTi shape memory alloy wire from cast ingot

    International Nuclear Information System (INIS)

    Bhagyaraj, J.; Ramaiah, K.V.; Saikrishna, C.N.; Bhaumik, S.K.; Gouthama

    2013-01-01

    Highlights: •Ti 2 Ni second phase particles forms in different sizes and shapes in cast ingot. •TEM evidences showed shearing/fragmentation of Ti 2 Ni during processing. •Matrix close to Ti 2 Ni experienced severe plastic deformation lead to amorphisation. •Ti 2 Ni interfaces were mostly faceted and assist in nucleation of martensite. •Heterogeneity of microstructure observed near to and away from Ti 2 Ni. -- Abstract: Binary NiTi alloy is one of the commercially successful shape memory alloys (SMAs). Generally, the NiTi alloy composition used for thermal actuator application is slightly Ti-rich. In the present study, vacuum arc melted alloy of 50.2Ti–Ni (at.%) composition was prepared and characterized using optical, scanning and transmission electron microcopy. Formation of second phase particles (SPPs) in the cast alloy and their influence on development of microstructure during processing of the alloy into wire form has been investigated. Results showed that the present alloy contained Ti 2 Ni type SPPs in the matrix. In the cast alloy, the Ti 2 Ni particles form in varying sizes (1–10 μm) and shapes. During subsequent thermo-mechanical processing, these SPPs get sheared/fragmented into smaller particles with low aspect ratio. The presence of SPPs plays a significant role in refinement of the microstructure during processing of the alloy. During deformation of the alloy, the matrix phase around the SPPs experiences conditions similar to that observed in severe plastic deformation of metallic materials, leading to localized amorphisation of the matrix phase

  4. Structure and properties of TiC, VC, and TiC/VC thin films deposited by pulsed laser deposition

    International Nuclear Information System (INIS)

    Krzanowski, J.E.; Leuchtner, R.E.

    1996-01-01

    A study has been conducted on the mechanical, tribological and chemical properties of pulsed laser deposited (PLD) TiC, VC and TiC/VC thin films. The TiC films were deposited at 375 C and 5 mTorr Ar, while the TiC/VC films were deposited from a composite target at 475 C at pressures of base vacuum and 50 mTorr Ar. XRD analysis revealed the films had the expected B1 structure, although XPS analysis showed a significant oxygen content. Tribological studies were conducted using a ball-on-disk test, and the wear behavior depended on the surface condition and film composition. One TiC/VC film exhibited little wear but caused significant ball wear, indicating mixed carbide films are promising candidates for wear-resistant coatings

  5. Effects of TiB2 Particle and Short Fiber Sizes on the Microstructure and Properties of TiB2-Reinforced Composite Coatings

    Science.gov (United States)

    Lin, Yinghua; Yao, Jianhua; Wang, Liang; Zhang, Qunli; Li, Xueqiao; Lei, Yongping; Fu, Hanguang

    2018-03-01

    In this study, particle and short fiber-reinforced titanium matrix composite coatings are prepared via laser in situ technique using (0.5 and 50 μm) TiB2 and Ti powder as cladding materials. The microstructure and properties of the composite coatings are studied, and the changing mechanism of the microstructure is discussed. The results reveal that particle agglomeration is prone to appear with using fine TiB2 particles. Decomposition of the particles preferentially occurs with using coarse TiB2 particles. The cracks and pores on the surface of the coating are formed at a lower laser energy density. With the increase in the laser energy density, cracking on the surface of the coating diminishes, but the coating exhibits depression behavior. The depression extent of the coating using fine TiB2 particle as the reinforcement is much less than that of the coating using coarse TiB2 particle. Moreover, the size of the aggregate and the tendency of cracking can be reduced with the increase in Ti addition. Meanwhile, short TiB fiber bundles are formed by the diffusion mechanism of rod aggregate, and randomly oriented TiB short fibers are formed mainly by the dissolution-precipitation mechanism of fine TiB2 particles. Moreover, the growth of short TiB fibers can be in an alternating manner between B27 and Bf structures. The micro-hardness and wear resistance of the coatings are evidently higher than that of the titanium alloy substrate. The wear resistance of the large size TiB2 coating is higher than that of the small size TiB2 coating under the condition of low load.

  6. Characterization of irradiation damage distribution near TiO2/SrTiO3 interfaces using coherent acoustic phonon interferometry

    International Nuclear Information System (INIS)

    Yarotski, Dmitry; Yan Li; Jia Quanxi; Taylor, Antoinette J.; Fu Engang; Wang Yongqiang; Uberuaga, Blas P.

    2012-01-01

    We apply ultrafast coherent acoustic phonon interferometry to characterize the distribution of the radiation damage near the TiO 2 /SrTiO 3 interfaces. We show that the optical and mechanical properties of anatase TiO 2 remain unaffected by the radiation dosages in the 0.1÷5 dpa (displacements per atom) range, while the degraded optical response indicates a significant defect accumulation in the interfacial region of SrTiO 3 at 0.1 dpa and subsequent amorphization at 3 dpa. Comparison between the theoretical simulations and the experimental results reveals an almost threefold reduction of the sound velocity in the irradiated SrTiO 3 layer with peak damage levels of 3 and 5 dpa.

  7. Storage of Hydrogen in the Ti-Zr System; Almacenamiento de hidrogeno en el sistema Ti-Zr

    Energy Technology Data Exchange (ETDEWEB)

    Salmones, J.; Zeifert, B. [Instituto Politecnico Nacional, ESIQIE, Mexico D.F. (Mexico)]. E-mail: jose_salmones@yahoo.com.mx; Ortega-Aviles, M. [Instituto Politecnico Nacional, Mexico D.F. (Mexico); Contreras-Larios, J. L. [Universidad Autonoma Metropolitana, Mexico D.F. (Mexico); Garibay-Febles, V. [Instituto Mexicano del Petroleo, Mexico D.F. (Mexico)

    2009-09-15

    This research was conducted to contribute to the study of hydrogen storage systems, synthesizing and characterizing two Ti-Zr based systems: I) titanium dioxide (TiO{sub 2}) + zirconium acetylacetonate (C{sub 20}H{sub 28}O{sub 8}Zr) and II) titanium dioxide (TiO{sub 2}) + zirconium tetrachloride (ZrCl{sub 4}). Both systems were prepared using mechanical grinding under the same conditions, with a composition of 50% Ti and Zr weights and grinding times of 2, 5, 7, 15, 30 and 70 hours. The samples were evaluated with hydrogen absorption tests and characterized with BET, DRX and MET. The results of hydrogen storage for one absorption-desorption cycle, at ambient temperature and pressure, showed that the samples from system I absorbed the greatest amount of hydrogen, but did not desorb them, while samples from system II liberated the hydrogen absorbed in them. The increase in temperature from mechanical grinding is directly associated with changes in the adsorption capacity of hydrogen, the size of the particle and formation of new components, as shows by BET measurements, XRD diffractograms and MET micrographs. The formation of Ti and Zr oxide nanoparticles in the samples in series II were associated with the desorption capacity of hydrogen. [Spanish] Esta investigacion se realizo para contribuir al estudio de sistemas para almacenamiento de hidrogeno, sintetizando y caracterizando dos sistemas base Ti-Zr: I) dioxido de titanio (TiO{sub 2}) + acetilacetonato de zirconio (C{sub 20}H{sub 28}O{sub 8}Zr) y II) dioxido de titanio (TiO{sub 2}) + tetracloruro de zirconio (ZrCl{sub 4}). Ambos sistemas se prepararon por molienda mecanica a las mismas condiciones, con composicion de 50% en peso de Ti y Zr y tiempos de molienda de 2, 5, 7, 15, 30 y 70 hrs. Las muestras fueron evaluadas mediante pruebas de absorcion de hidrogeno y caracterizadas por BET, DRX y MET. Los resultados de almacenamiento de hidrogeno para un ciclo de absorcion-desorcion, a presion y temperatura ambientes

  8. Enhanced photoelectrocatalytic performance for degradation of diclofenac and mechanism with TiO2 nano-particles decorated TiO2 nano-tubes arrays photoelectrode

    International Nuclear Information System (INIS)

    Cheng, Xiuwen; Liu, Huiling; Chen, Qinghua; Li, Junjing; Wang, Pu

    2013-01-01

    In this study, TiO 2 nano-particles decorated TiO 2 nano-tubes arrays (TiO 2 NPs/TiO 2 NTAs) photoelectrodes have been successfully prepared through anodization, combined with ultrasonic strategy, followed by annealing post-treatment. The morphology and structure of the as-prepared TiO 2 NPs/TiO 2 NTAs photoelectrodes were characterized by scanning electrons microscopy (SEM), N 2 adsorption/desorption isotherms, X-ray diffraction (XRD) and UV–visible light diffuse reflection spectroscopy (DRS). In addition, the generation of hydroxyl radicals (·OH) was detected by a photoluminescence (PL) spectra using terephthalic acid (TA) as a probe molecule. Furthermore, the photoelectrochemical (PECH) properties of TiO 2 NPs/TiO 2 NTAs photoanode were investigated through transient open circuit potential (OCP), photocurrent response (PCR) and electrochemical impedance spectroscopy (EIS). It was found that TiO 2 NPs/TiO 2 NTAs photoelectrode exhibited a distinct decrease of OCP of −0.219 mV cm −2 and PCR of 0.049 mA cm −2 , while a significantly enhanced photoelectrocatalytic (PEC) efficiency of 63.6% (0.4 V vs. SCE) for the degradation of diclofenac. Moreover, the enhanced PEC mechanism of TiO 2 NPs/TiO 2 NTAs photoanode was proposed. The high PEC performance could be attributed to the decoration of TiO 2 NPs, which could improve the mobility and separation efficiency of photoinduced charge carriers under external potential

  9. First-principles study on ferrite/TiC heterogeneous nucleation interface

    International Nuclear Information System (INIS)

    Yang, Jian; Zhang, Pengfei; Zhou, Yefei; Guo, Jing; Ren, Xuejun; Yang, Yulin; Yang, Qingxiang

    2013-01-01

    Highlights: ► Interface stability of ferrite (1 0 0)/TiC (1 0 0) was studied. ► The effectiveness of TiC as the heterogeneous nuclei of ferrite was analyzed. ► Ti-termination and C-termination are the two binding modes for ferrite/TiC interface. ► Interfacial energy of the Ti-termination is larger than that of the C-termination. ► On C-termination, ability of TiC promotes ferrite heterogeneous nucleation is strong. -- Abstract: Interface atomic structure, bonding character, cohesive energy and interfacial energy of ferrite (1 0 0)/TiC (1 0 0) were studied using a first-principles density functional plane-wave ultrasoft pseudopotential method. Meanwhile, the effectiveness of TiC as the heterogeneous nuclei of ferrite was analyzed. The results indicated that, TiC bonding is dominated by the C-2p, C-2s and Ti-3d electrons, which exhibits high covalency. With increase of the atomic layers, the interfacial energies of ferrite and TiC are both declined rapidly and stabilized gradually. There are two binding modes for TiC as the heterogeneous nuclei of ferrite, which are Fe atoms above the Ti atoms (Ti-termination) and Fe atoms above the C atoms (C-termination). Interfacial energy of the Ti-termination is larger than that of the C-termination, which means that for Fe atoms above the C atoms, the ability of TiC promotes ferrite heterogeneous nucleation on its surface is larger than that for Fe atoms above the Ti atoms

  10. Microporous TiO2-WO3/TiO2 films with visible-light photocatalytic activity synthesized by micro arc oxidation and DC magnetron sputtering

    International Nuclear Information System (INIS)

    Wu, Kee-Rong; Hung, Chung-Hsuang; Yeh, Chung-Wei; Wu, Jiing-Kae

    2012-01-01

    Highlights: ► A simple MAO is used to prepare porous WO 3 /TiO 2 layer on Ti sheet as a visible-light enabled catalyst. ► The photocatalytic activity of the WO 3 /TiO 2 is enhanced by sputtering over an N,C-TiO 2 layer. ► This is ascribed to the synergetic effect of hybrid sample prepared by two-step method. - Abstract: This study reports the preparation of microporous TiO 2 -WO 3 /TiO 2 films with a high surface area using a two-step approach. A porous WO 3 /TiO 2 template was synthesized by oxidizing a titanium sheet using a micro arc oxidation (MAO) process. This sheet was subsequently overlaid with a visible light (Vis)-enabled TiO 2 (N,C-TiO 2 ) film, which was deposited by codoping nitrogen (N) and carbon (C) ions into a TiO 2 lattice using direct current magnetron sputtering. The resulting microporous TiO 2 -WO 3 /TiO 2 film with a 0.38-μm-thick N,C-TiO 2 top-layer exhibited high photocatalytic activity in methylene blue (MB) degradation among samples under ultraviolet (UV) and Vis irradiation. This is attributable to the synergetic effect of two-step preparation method, which provides a highly porous microstructure and the well-crystallized N,C-TiO 2 top-layer. This is because a higher surface area with high crystallinity favors the adsorption of more MB molecules and more photocatalytic active areas. Thus, the microporous TiO 2 -WO 3 /TiO 2 film has promising applications in the photocatalytic degradation of dye solution under UV and Vis irradiation. These results imply that the microporous WO 3 /TiO 2 can be used as a template of hybrid electrode because it enables rapid fabrication.

  11. Ion beam sputter deposited TiAlN films for metal-insulator-metal (Ba,Sr)TiO3 capacitor application

    International Nuclear Information System (INIS)

    Lee, S.-Y.; Wang, S.-C.; Chen, J.-S.; Huang, J.-L.

    2008-01-01

    The present study evaluated the feasibility of TiAlN films deposited using the ion beam sputter deposition (IBSD) method for metal-insulator-metal (MIM) (Ba,Sr)TiO 3 (BST) capacitors. The BST films were crystallized at temperatures above 650 deg. C. TiAlN films deposited using the IBSD method were found having smooth surface and low electrical resistivity at high temperature conditions. TiAlN films showed a good diffusion barrier property against BST components. The J-E (current density-electric field) characteristics of Al/BST/TiAlN capacitors were good, with a high break down electric field of ± 2.5 MV/cm and a leakage current density of about 1 x 10 -5 A/cm 2 at an applied field of ± 0.5 MV/cm. Thermal stress and lateral oxidation that occurred at the interface damaged the capacitor stacking structure. Macro holes that dispersed on the films resulted in higher leakage current and inconsistent J-E characteristics. Vacuum annealing with lower heating rate and furnace cooling, and a Ti-Al adhesion layer between TiAlN and the SiO 2 /Si substrate can effectively minimize the stress effect. TiAlN film deposited using IBSD can be considered as a potential electrode and diffusion barrier material for MIM BST capacitors

  12. Model Penilaian Kapabilitas Proses Optimasi Resiko Ti Berdasarkan Cobit 5

    OpenAIRE

    Putri, Rahmi Eka

    2015-01-01

    Teknologi informasi (TI) saat ini telah menjadi kebutuhan yang mendasar bagi setiap organisasi dan tidak jarang sebuah organisasi memiliki ketergantungan yang tinggi terhadap TI. Resiko penggunaan TI di organisasi harus dikelola dengan baik, agar resiko penggunaan TI dapat diminimalisasi dan TI dapat membantu dalam pencapaian tujuan organisasi. Optimasi resiko penggunaan TI di organisasi merupakan salah satu domain dalam tata kelola TI berdasarkan COBIT 5. Proses ini bertujuan untuk memastika...

  13. Structure, mechanical properties, and grindability of dental Ti-Zr alloys.

    Science.gov (United States)

    Ho, Wen-Fu; Chen, Wei-Kai; Wu, Shih-Ching; Hsu, Hsueh-Chuan

    2008-10-01

    Structure, mechanical properties and grindability of a series of binary Ti-Zr alloys with zirconium contents ranging from 10 to 40 wt% have been investigated. Commercially pure titanium (c.p. Ti) was used as a control. Experimental results indicated that the diffraction peaks of all the Ti-Zr alloys matched those for alpha Ti. No beta-phase peaks were found. The hardness of the Ti-Zr alloys increased as the Zr contents increased, and ranged from 266 HV (Ti-10Zr) to 350 HV (Ti-40Zr). As the concentration of zirconium in the alloys increased, the strength, elastic recovery angles and hardness increased. Moreover, the elastically recoverable angle of Ti-40Zr was higher than of c.p. Ti by as much as 550%. The grindability of each metal was found to be largely dependent on the grinding conditions. The Ti-40Zr alloy had a higher grinding rate and grinding ratio than c.p. Ti at low speed. The grinding rate of the Ti-40Zr alloy at 500 m/min was about 1.8 times larger than that of c.p. Ti, and the grinding ratio was about 1.6 times larger than that of c.p. Ti. Our research suggested that the Ti-40Zr alloy has better mechanical properties, excellent elastic recovery capability and improved grindability at low grinding speed. The Ti-40Zr alloy has a great potential for use as a dental machining alloy.

  14. Microstructure of Laser Clad TiC/FeAl Composite Coating and Growth Mechanism of Primary TiC Carbide%激光熔覆TiC/FeAl复合材料涂层显微组织及初生TiC生长机制研究

    Institute of Scientific and Technical Information of China (English)

    陈瑶; 王华明

    2003-01-01

    利用激光熔覆技术在 1Cr18Ni9Ti奥氏体不锈钢基体上制得了以 TiC为增强相、以 FeAl金属间化合物为基体的快速凝固 TiC/FeAl复合材料涂层,分析了该涂层的显微组织及初生 TiC的生长形态和生长机制.研究结果表明,激光熔覆 TiC/FeAl快速凝固复合材料涂层主要由初生 TiC碳化物、初生 FeAl树枝晶和枝晶间少量的 FeAl/TiC共晶组成,初生 TiC具有独特的径向辐射分枝小面枝晶团簇状生长形态,其生长机制为侧向生长.

  15. Surface modification of coronary artery stent by Ti-O/Ti-N complex film coating prepared with plasma immersion ion implantation and deposition

    International Nuclear Information System (INIS)

    Huang, N.; Leng, Y.X.; Yang, P.

    2006-01-01

    This paper reported the work of surface coating of Ti-O/Ti-N complex films on coronary stents by means of the plasma immersion ion implantation/deposition process. The deformation behavior of the Ti-O/Ti-N coated stainless steel stents was investigated. In vivo investigation of the anticoagulation behavior of Ti-O coated coronary stents was also performed. The results of mechanical characterization of the Ti-O/Ti-N coated stents show that the film has strong binding strength, and to some extent the ability to withstand plastic deformation. The biological response behavior of the coated stent surface was significantly different from the uncoated. The results of implantation of stents into rabbit ventral aorta show no thrombus formation on the surfaces of the Ti-O coated stents, although serious coagulation had occurred on the surfaces of unmodified stents over a period of 4 weeks under conditions with no anticoagulant

  16. Corrosion behavior of austenitic stainless steel containing Ti

    International Nuclear Information System (INIS)

    Cha, Sueng Ok; Choe, Han Cheol; Kim, Kwan Hyu

    1998-01-01

    Corrosion behavior of austenitic stainless steel containing Ti has been studied by using electrochemical techniques. The samples containing Ti from 0.1 to 1.0 wt% were solutionized at 1050 .deg. C for 1hr and then sensitized at 650 .deg. C for 5hr under argon atmosphere. Microstructure and phase analysis of the samples after heat treatment and corrosion tests were carried out by using XRD. TEM, SEM and optical microscope. The amount of δ-ferrite and TiC precipitates in matrix increased as the Ti content increased. In the sensitized samples, Cr 23 C 6 precipitates were observed at γ/δ interface. Degree Of Sensitization(DOS) was lower than 1.0 in all of the solutionized samples and the sensitized samples of Ti content above 0.4% wt% whereas the sensitized samples of Ti content lower than 0.4 wt% showed DOS higher than 1.0. Intergranular attack appeared mainly at grain boundaries in the sensitized sample containing 0.1 wt% Ti and at the γ/δ interface of the higher Ti content. In the latter, however, the attack was not so severe. Pitting potential(E pit ) and repassivation potential(E rep ) of the solutionized and sensitized samples were increased with increasing Ti content. The number and size of the pits decreased with increasing Ti content in the sensitized samples. The pits nucleated at Cr 23 C 6 site and the γ/δ interface

  17. Anodic Fabrication of Ti-Nb-Zr-O Nanotube Arrays

    Directory of Open Access Journals (Sweden)

    Qiang Liu

    2014-01-01

    Full Text Available Highly ordered Ti-Nb-Zr-O nanotube arrays were fabricated through pulse anodic oxidation of Ti-Nb-Zr alloy in 1 M NaH2PO4 containing 0.5 wt% HF electrolytes. The effect of anodization parameters and Zr content on the microstructure and composition of Ti-Nb-Zr-O nanotubes was investigated using a scanning electron microscope equipped with energy dispersive X-ray analysis. It was found that length of the Ti-Nb-Zr-O nanotubes increased with increase of Zr contents. The diameter and the length of Ti-Nb-Zr-O nanotubes could be controlled by pulse voltage. XRD analysis of Ti-Nb-Zr-O samples annealed at 500°C in air indicated that the (101 diffraction peaks shifted from 25.78° to 25.05° for annealed Ti-Nb-Zr-O samples with different Zr contents because of larger lattice parameter of Ti-Nb-Zr-O compared to that of undoped TiO2.

  18. Preparation of Ti3C2 and Ti2C MXenes by fluoride salts etching and methane adsorptive properties

    Science.gov (United States)

    Liu, Fanfan; Zhou, Aiguo; Chen, Jinfeng; Jia, Jin; Zhou, Weijia; Wang, Libo; Hu, Qianku

    2017-09-01

    Here we reported the preparation of Ti3C2 MXene and Ti2C MXene by etching Ti3AlC2 and Ti2AlC with various fluoride salts in hydrochloric acid (HCl), including lithium fluoride (LiF), sodium fluoride (NaF), potassium fluoride (KF), and ammonium fluoride (NH4F). As-prepared Ti2C was further delaminated by urea, dimethylsulfoxide or ammonium hydroxide. Based on theoretical calculation and XPS results, the type of positive ions (Li+, Na+, K+, or NH4+) in etchant solution affect the surface structure of prepared MXene, which, in turn, affects the methane adsorption properties of MXene. The highest methane adsorption capacity is 8.5 cm3/g for Ti3C2 and 11.6 cm3/g for Ti2C. MXenes made from LiF and NH4F can absorb methane under high pressure and can keep methane under normal pressure, these MXenes may have important application on capturing methane or other hazardous gas molecules. MXenes made from NaF and KF can absorb methane under high pressure and release methane under low pressure. They can have important application in the adsorb storage of nature gas.

  19. Microstructure development of in situ porous TiO/Cu composites

    International Nuclear Information System (INIS)

    Qin, Q.D.; Huang, B.W.; Li, W.; Shao, F.

    2016-01-01

    An in situ porous TiO/Cu composite is successfully prepared using powder metallurgy by the reaction of Ti_2CO and Cu powder. Ti_2CO powder is produced by the carbothermic reduction of titanium dioxide (TiO_2) at 1000 °C. Morphological examination of the composite shows that the porosity of composites lies in the range between 10.2% and 35.2%. As the volume fraction of TiO increases, the size of TiO becomes more fine. Scanning electron microscopy (SEM) of the fracture morphology indicates that TiO particles and the Cu matrix are connected by a Cu–Ti phase. - Highlights: • An porous TiO/Cu composite is successfully prepared by powder metallurgy technology. • The porosity of composites lies in the range between 10.2% and 35.2%. • The TiO particles and the Cu matrix are connected by a Cu-Ti phase.

  20. Superconductivity of TiNCl intercalated with diamines

    International Nuclear Information System (INIS)

    Yamanaka, Shoji; Umemoto, Keita

    2010-01-01

    Intercalation compounds of TiNCl with ethylenediamine (EDA) and hexamethylenediamine (HDA) were prepared. The basal spacing of TiNCl increased by 3.3-3.9 A upon intercalation, implying that the molecules are lying with the alkyl chains parallel to the TiNCl layers in both compounds. The intercalated compounds showed superconductivity with transition temperatures (T c s) of 10.5 and 15.5 K for EDA and HDA, respectively, which are higher than 8.6 K of pyridine (Py) intercalated compound, Py 0.25 TiNCl.