Domain-walls motion in glass-coated CoFeSiB amorphous microwires

Energy Technology Data Exchange (ETDEWEB)

Antonov, A.S. E-mail: as.antonov@mtu-net.ru; Buznikov, N.A.; Granovsky, A.B.; Joura, A.V.; Rakhmanov, A.L.; Yakunin, A.M

2002-08-01

A method for observation of domain-walls motion in amorphous microwires with circular magnetic anisotropy is proposed. Using the method, the magnetization reversal of glass-coated Co-based microwires induced by current pulses of high amplitude is studied. The magnetization reversal is shown to occur due to the nucleation of the domain walls at the sample ends and their subsequent motion along the microwire. The dependencies of the domain-wall velocity on the current pulse amplitude and a longitudinal DC magnetic field are measured. A model describing main features of experimental data is presented.

Domain-walls motion in glass-coated CoFeSiB amorphous microwires

International Nuclear Information System (INIS)

Antonov, A.S.; Buznikov, N.A.; Granovsky, A.B.; Joura, A.V.; Rakhmanov, A.L.; Yakunin, A.M.

2002-01-01

A method for observation of domain-walls motion in amorphous microwires with circular magnetic anisotropy is proposed. Using the method, the magnetization reversal of glass-coated Co-based microwires induced by current pulses of high amplitude is studied. The magnetization reversal is shown to occur due to the nucleation of the domain walls at the sample ends and their subsequent motion along the microwire. The dependencies of the domain-wall velocity on the current pulse amplitude and a longitudinal DC magnetic field are measured. A model describing main features of experimental data is presented

In vitro metal ion release and biocompatibility of amorphous Mg{sub 67}Zn{sub 28}Ca{sub 5} alloy with/without gelatin coating

Energy Technology Data Exchange (ETDEWEB)

Chan, W.Y., E-mail: chan.wing.yue@sgh.com.sg [School of Mechanical and Aerospace Engineering, Nanyang Technological University (Singapore); Department of Plastic, Reconstructive and Aesthetic Surgery, Singapore General Hospital (Singapore); Chian, K.S.; Tan, M.J. [School of Mechanical and Aerospace Engineering, Nanyang Technological University (Singapore)

2013-12-01

Amorphous zinc-rich Mg–Zn–Ca alloys have exhibited good tissue compatibility and low hydrogen evolution in vivo. However, suboptimal cell–surface interaction on magnesium alloy surface observed in vitro could lead to reduced integration with host tissue for regenerative purpose. This study aims to improve cell–surface interaction of amorphous Mg{sub 67}Zn{sub 28}Ca{sub 5} alloy by coating a gelatin layer by electrospinning. Coated/uncoated alloys were immersed and extracted for 3 days under different CO{sub 2}. The immersion results showed that pH and metal ion release in the alloy extracts were affected by gelatin coating and CO{sub 2}, suggesting their roles in alloy biocorrosion and a mechanism has been proposed for the alloy–CO{sub 2} system with/without coating. Cytotoxicity results are evident that gelatin-coated alloy with 2-day crosslinking not only exhibited no indirect cytotoxicity, but also supported attachment of L929 and MG63 cell lines around/on the alloy with high viability. Therefore, amorphous Mg{sub 67}Zn{sub 28}Ca{sub 5} alloy coated with gelatin by electrospinning technique provides a useful method to improve alloy biocompatibility. - Highlights: • Electrospinning is a new method to coat amorphous Mg{sub 67}Zn{sub 28}Ca{sub 5} alloy with gelatin. • Gelatin-coated alloy has differential effect on pH and ion release at various CO{sub 2}. • L929 cell proliferation correlates with Mg{sup 2+} level in alloy extracts. • Biomimetic gelatin coating significantly improves cell–surface interaction.

Study of electroless Ni-W-P alloy coating on martensitic stainless steel

Energy Technology Data Exchange (ETDEWEB)

Nikitasari, Arini, E-mail: arini-nikitasari@yahoo.com; Mabruri, Efendi, E-mail: efendi-lipi@yahoo.com [Research Center for Metallurgy and Materials, Indonesian Institute of Sciences (470 Building, Puspiptek, Serpong, Indonesia 15313) (Indonesia)

2016-04-19

Electroless nickel phospor (Ni-P) is widely used in many industries due to their corrosion and wear resistance, coating uniformity, and ability to coat non-conductive surfaces. The unique properties of tungsten such as high hardness, higher melting point, lower coefficient of linear thermal expansion, and high tensile strength have created a lot of interest in developing ternary Ni-W-P alloys. This article presents the study of electroless Ni-W-P alloys coating using acid or alkaline bath on martensitic stainless steel. Nickel sulfate and sodium tungstate were used as nickel and tungsten sources, respectively, and sodium hypophosphite was used as a reducing agent. Acid or alkaline bath refer to bath pH condition was adjusted by adding sulfuric acid. Martensitic stainless steel was immersed in Ni-W-P bath for 15, 30, and 60 minutes. The substrate of martensitic stainless steel was subjected to pre-treatment (polishing and cleaning) and activation prior to electroless plating. The plating characteristics were investigated for concentration ratio of nickel and hypophosphite (1:3), sodium tungstate concentration 0,1 M, immersion time (15 min, 30 min, 60 min), and bath condition (acid, alkaline). The electroless Ni-W-P plating was heat treated at 400°C for 1 hour. Deposits were characterized using scanning electron microscope (SEM) and corrosion measurement system (CMS).

Characterization of Amorphous and Co-Amorphous Simvastatin Formulations Prepared by Spray Drying

Directory of Open Access Journals (Sweden)

Goedele Craye

2015-12-01

Full Text Available In this study, spray drying from aqueous solutions, using the surface-active agent sodium lauryl sulfate (SLS as a solubilizer, was explored as a production method for co-amorphous simvastatin–lysine (SVS-LYS at 1:1 molar mixtures, which previously have been observed to form a co-amorphous mixture upon ball milling. In addition, a spray-dried formulation of SVS without LYS was prepared. Energy-dispersive X-ray spectroscopy (EDS revealed that SLS coated the SVS and SVS-LYS particles upon spray drying. X-ray powder diffraction (XRPD and differential scanning calorimetry (DSC showed that in the spray-dried formulations the remaining crystallinity originated from SLS only. The best dissolution properties and a “spring and parachute” effect were found for SVS spray-dried from a 5% SLS solution without LYS. Despite the presence of at least partially crystalline SLS in the mixtures, all the studied formulations were able to significantly extend the stability of amorphous SVS compared to previous co-amorphous formulations of SVS. The best stability (at least 12 months in dry conditions was observed when SLS was spray-dried with SVS (and LYS. In conclusion, spray drying of SVS and LYS from aqueous surfactant solutions was able to produce formulations with improved physical stability for amorphous SVS.

Characterization of Amorphous and Co-Amorphous Simvastatin Formulations Prepared by Spray Drying.

Science.gov (United States)

Craye, Goedele; Löbmann, Korbinian; Grohganz, Holger; Rades, Thomas; Laitinen, Riikka

2015-12-03

In this study, spray drying from aqueous solutions, using the surface-active agent sodium lauryl sulfate (SLS) as a solubilizer, was explored as a production method for co-amorphous simvastatin-lysine (SVS-LYS) at 1:1 molar mixtures, which previously have been observed to form a co-amorphous mixture upon ball milling. In addition, a spray-dried formulation of SVS without LYS was prepared. Energy-dispersive X-ray spectroscopy (EDS) revealed that SLS coated the SVS and SVS-LYS particles upon spray drying. X-ray powder diffraction (XRPD) and differential scanning calorimetry (DSC) showed that in the spray-dried formulations the remaining crystallinity originated from SLS only. The best dissolution properties and a "spring and parachute" effect were found for SVS spray-dried from a 5% SLS solution without LYS. Despite the presence of at least partially crystalline SLS in the mixtures, all the studied formulations were able to significantly extend the stability of amorphous SVS compared to previous co-amorphous formulations of SVS. The best stability (at least 12 months in dry conditions) was observed when SLS was spray-dried with SVS (and LYS). In conclusion, spray drying of SVS and LYS from aqueous surfactant solutions was able to produce formulations with improved physical stability for amorphous SVS.

Novel trends in the study of magnetically soft Co-based amorphous glass-coated wires

International Nuclear Information System (INIS)

Chiriac, H.; Ovari, T.-A.

2011-01-01

An overview of the recent progress and state-of-the-art results in the investigation of the amorphous glass-coated wires with nearly zero magnetostriction is presented. These versatile microwires display enhanced soft magnetic properties, which make them suitable as sensing elements in various sensors for biomedical and automotive applications. Current results on their magnetic characteristics refer to a major refinement of their core-shell magnetic structure by taking into account the interdomain wall and to the thorough analysis of the magnetization within the outer shell. Experimental techniques such as giant magneto-impedance, magneto-resistance, and magneto-optical Kerr effect measurements are employed to prove the outcome of the theoretical calculations. The impact of the magnetic structure of the outer shell on the propagation of domain walls in bistable amorphous wires is analyzed. Very recent results on the magnetization process in nearly zero magnetostrictive amorphous glass-coated wires with submicron dimensions are also reviewed. - Highlights: → The most recent advances in the study of amorphous glass-coated wires with nearly zero magnetostriction are surveyed. → Major progress in the study of their domain structure: the wide interdomain wall, which affects high frequency phenomena. → The magnetization of the outer shell depends on wire diameter and affects the wall propagation in bistable samples. → These novel results are important for future sensor applications of nearly zero magnetostrictive amorphous microwires.

Amorphous structure evolution of high power diode laser cladded Fe–Co–B–Si–Nb coatings

International Nuclear Information System (INIS)

Zhu Yanyan; Li Zhuguo; Huang Jian; Li Min; Li Ruifeng; Wu Yixiong

2012-01-01

Highlights: ► Fabricated amorphous composited coating by high power diode laser cladding with single track. ► Lower dilution and higher scanning speed are desired to obtain higher amorphous phase fraction. ► White spots phase with high content of Nb embedded in the amorphous matrix. - Abstract: Fe–Co–B–Si–Nb coatings were fabricated on the surface of low carbon steel using high power diode laser cladding of [(Fe 0.5 Co 0.5 ) 0.75 B 0.2 Si 0.05 ] 95.7 Nb 4.3 amorphous powders at three different scanning speeds of 6, 17 and 50 m/s. At each scanning speed, laser power was optimized to obtain low dilution ratio. Scanning electron microscopy, X-ray diffraction, transmission electron microscopy with energy dispersive spectrometer and electron probe micro analysis were carried out to characterize the microstructure and chemical composition of the cladded coatings. Differential scanning calorimetry was also carried out to investigate the fraction of the amorphous phase. The results showed that dilution ratio and scanning speed were the two main factors for fabricating Fe–Co–B–Si–Nb amorphous coating by high power diode laser cladding. Low dilution ratio was crucial for the formation of amorphous phase. When the dilution ratio was low, the fraction of amorphous phase in the cladded coatings increased upon increasing the scanning speed.

Lubricated sliding wear behaviour of Ni-P-W multilayered alloy coatings produced by pulse plating

DEFF Research Database (Denmark)

Panagopoulos, C. N.; Papachristos, V. D.; Christoffersen, Lasse

2000-01-01

The lubricated sliding wear behaviour of Ni-P-W multilayered alloy coatings sliding against hardened steel discs was studied, in a pin-on-disc set-up. The multilayered coatings had been deposited on mild steel pins by pulse plating and they consisted of ternary Ni-P-W layers of high and low W con...... lubrication regimes. The wear mechanisms in each lubrication regime were studied and in mixed lubrication regime, the effect of normal load and sliding speed on wear volume and friction coefficient was also studied. (C) 2000 Elsevier Science S.A. All rights reserved....

Distribution of the partial pressure of CO2 in surface water (pCO2w) between Japan and the Hawaiian Islands: pCO2w-SST relationship in the winter and summer

International Nuclear Information System (INIS)

Inoue, Hisayuki Y.; Ishii, Masao; Matsueda, Hidekazu; Kawano, Takeshi; Murata, Akihiko; Takasugi, Yoshio

2003-01-01

On the basis of measurements of the partial pressure of carbon dioxide in surface seawater (pCO 2 w) between Japan and the Hawaiian Islands in winter and summer, we examined the relationship between pCO 2 w and the sea surface temperature (SST) in the North Pacific Subtropical Gyre (NPSG). In winter, pCO 2 w correlated well with the SST (0.14-0.24%/deg C), suggesting a monotonous change in the carbonate system. However, in summer, five different pCO 2 w-SST relationships were found in the NPSG (including the Kuroshio Extension) due to changes in the relative contribution of ocean dynamics (upwelling, vertical mixing and advection), biological activity in the absence (very low level) of macro-nutrients and thermodynamics. The increase in pCO 2 w corresponding to a unit increase in the SST from January to July was low (<2.5%/deg C) west (leeward side) of the Hawaiian Islands (19-22 deg N, 158-168 deg W) and in the Kuroshio Extension (33-35 deg N, 140-165deg E), and high (3%/deg C) south of the Kuroshio Extension (25-30 deg N, 180-165 deg W) and the Hawaiian Islands (15-19 deg N, 157-162 deg W). This suggested that the drawdown of dissolved inorganic carbon was affected by the enhanced biological activity due to upwelling events associated with eddies and/or the transport of dissolved nutrients from gyre edges to the interior

Microwave absorption property of the diatomite coated by Fe-CoNiP films

International Nuclear Information System (INIS)

Yan, Zhenqiang; Cai, Jun; Xu, Yonggang; Zhang, Deyuan

2015-01-01

Highlights: • The bio-absorbent coated Fe-CoNiP was fabricated by electroless and CVD. • The EM parameters were enlarged as Fe coated on the diatomite. • The coating CIPs play a key role in the enhancement mechanism. • The Fe-CoNiP diatomite had a better absorbing and shielding properties. - Abstract: A bio-absorbent of Fe-CoNiP coated on the diatomite was fabricated by way of electroless plating of CoNiP and subsequent chemical vapor deposition of Fe. The surface morphology and composition of the above-mentioned diatomite particles at different stage were characterized with the scanning electron microscopy and the energy spectrum analysis respectively, and the results showed that the diatomite was successfully coated with CoNoP and Fe (carbony iron). The complex permittivity and permeability of composites filled with the bio-absorbent and paraffin was measured in frequency range of 2–18 GHz, and then the microwave reflection loss (RL) and the shielding effectiveness (SE) were calculated. The results showed that the permittivity and the permeability were both enlarged as Fe films were coated onto the CoNiP-coated diatomite, which was attributed to the excellent electromagnetic property of carbonyl irons. The composites made with the Fe-CoNiP diatomite had a better absorbing property (minimum RL −11.0 dB) as well as the shielding property (maximum SE 5.6 dB) at thickness 2 mm. It indicated the absorption property was mainly due to the attenuation on the microwave, and the Fe-CoNiP diatomite could be an effective absorbent with low-density

Microwave absorption property of the diatomite coated by Fe-CoNiP films

Energy Technology Data Exchange (ETDEWEB)

Yan, Zhenqiang; Cai, Jun; Xu, Yonggang, E-mail: xuyonggang221@163.com; Zhang, Deyuan

2015-08-15

Highlights: • The bio-absorbent coated Fe-CoNiP was fabricated by electroless and CVD. • The EM parameters were enlarged as Fe coated on the diatomite. • The coating CIPs play a key role in the enhancement mechanism. • The Fe-CoNiP diatomite had a better absorbing and shielding properties. - Abstract: A bio-absorbent of Fe-CoNiP coated on the diatomite was fabricated by way of electroless plating of CoNiP and subsequent chemical vapor deposition of Fe. The surface morphology and composition of the above-mentioned diatomite particles at different stage were characterized with the scanning electron microscopy and the energy spectrum analysis respectively, and the results showed that the diatomite was successfully coated with CoNoP and Fe (carbony iron). The complex permittivity and permeability of composites filled with the bio-absorbent and paraffin was measured in frequency range of 2–18 GHz, and then the microwave reflection loss (RL) and the shielding effectiveness (SE) were calculated. The results showed that the permittivity and the permeability were both enlarged as Fe films were coated onto the CoNiP-coated diatomite, which was attributed to the excellent electromagnetic property of carbonyl irons. The composites made with the Fe-CoNiP diatomite had a better absorbing property (minimum RL −11.0 dB) as well as the shielding property (maximum SE 5.6 dB) at thickness 2 mm. It indicated the absorption property was mainly due to the attenuation on the microwave, and the Fe-CoNiP diatomite could be an effective absorbent with low-density.

Rare earth effect on microstructure, mechanical and tribological properties of CoCrW coatings

International Nuclear Information System (INIS)

Zhang Zhenyu; Lu Xinchun; Han Baolei; Luo Jianbin

2007-01-01

Eight different CoCrW coatings doped with rare earth oxide were deposited by supersonic plasma spraying (SPS). Environmental scanning electron microscopy, microhardness tester, X-ray diffractometer, and self-developed tribometer for high temperature were employed to investigate the properties of sprayed coatings. The results show that rare earth can refine the microstructure effectively, and make the element distribution uniform, which leads to the increase of average microhardness and the corresponding decrease of fluctuation range of sectioned surface of SPS coatings. Furthermore, the rare earth can reduce the friction coefficient between the SPS coating and glass during the sliding process at about 973 K largely, and the mechanism of anti-friction is also discussed

Characterisation of electrodeposited and heat-treated Ni-Mo-P coatings

Energy Technology Data Exchange (ETDEWEB)

Melo, Regis L.; Casciano, Paulo N.S.; Correia, Adriana N.; Lima-Neto, Pedro de, E-mail: pln@ufc.br [Departamento de Quimica Analitica e Fisico-Quimica, Universidade Federal do Ceara, Fortaleza, CE (Brazil)

2012-07-01

The electrodeposition, hardness and corrosion resistance properties of Ni-Mo-P coatings were investigated. Characterisations of the electrodeposited coatings were carried out using scanning electron microscopy, X-ray diffraction and energy dispersive X-ray analysis techniques. Corrosion tests were performed at room temperature in 10-1 mol dm-3 NaCl solutions and by potentiodynamic linear polarisation. Amorphous Ni-Mo-P coatings were successfully obtained by electrodeposition using direct current. The coating composition showed to be dependent on the bath composition, current density and bath temperature. Both P and Mo contents contribute for the hardness properties of the Ni-Mo-P coatings and the absence of cracks is a requirement to produce electrodeposited Ni-Mo-P coatings with good hardness properties. The hardness values increase with heat-treatment temperature due to the precipitation of Ni, Ni{sub 3}P and NiMo phases during the heat treatment. The corrosion resistance of the electrodeposited Ni-Mo-P amorphous coatings increases with P content in the layer. Among the electrodeposited Ni-Mo-P amorphous coatings, Ni{sub 78}Mo{sub 10}P{sub 12} presented the best hardness and corrosion-resistance properties. The results showed that the addition of P is beneficial for the hardness and corrosion resistance properties of the Ni-Mo-based coatings. (author)

Research Progress on Laser Cladding Amorphous Coatings on Metallic Substrates

Directory of Open Access Journals (Sweden)

CHEN Ming-hui

2017-01-01

Full Text Available The microstructure and property of amorphous alloy as well as the limitations of the traditional manufacturing methods for the bulk amorphous alloy were briefly introduced in this paper.Combined with characteristics of the laser cladding technique,the research status of the laser cladding Fe-based,Zr-based,Ni-based,Cu-based and Al-based amorphous coatings on the metal substrates were mainly summarized.The effects of factors such as laser processing parameter,micro-alloying element type and content and reinforcing phase on the laser cladding amorphous coatings were also involved.Finally,the main problems and the future research directions of the composition design and control of the laser-cladded amorphous coating,the design and optimization of the laser cladding process,and the basic theory of the laser cladding amorphous coatings were also put forward finally.

A chiral microwave absorbing absorbent of Fe–CoNiP coated on spirulina

Energy Technology Data Exchange (ETDEWEB)

Xu, Yonggang, E-mail: xuyonggang221@163.com [Science and Technology on Electromagnetic Scattering Laboratory, Shanghai, 200438 (China); Yuan, Liming [Science and Technology on Electromagnetic Scattering Laboratory, Shanghai, 200438 (China); Zhang, Deyuan [School of Mechanical Engineering and Automation, Beihang University, Beijing, 100191 (China)

2015-11-15

A chiral bio-absorbent of Fe–CoNiP coated on the spirulina was fabricated by the electroless and chemical vapor decomposition. The scanning electron microscopy (SEM) was used to evaluate the spirulina cells particle morphology. X-ray diffraction (XRD) patterns were done to analyze the particle crystal grain structure. The permittivity and permeability was measured by a vector network analyzer in frequency 8–18 GHz, and the reflection loss (RL) was calculated. The results showed the carbonyl iron particles (CIPs) and CoNiP were bonded to the spirulina surface, the permittivity and permeability could be enlarged as Fe films coated on the particles compared with the CoNiP spirulina, it was attributed to the excellent electromagnetic property of CIPs. The chiral Fe–CoNiP composites had a better absorbing property at 8–18 GHz than the CoNiP spirulina composite, the RL was −16.26 dB at 10.48 GHz, the absorbing band was 9.5–11.5 GHz of RL less than −10 dB, which indicated the Fe–CoNiP spirulina could be an effective absorbent used in 8–18 GHz. - Highlights: • Absorbers filled with Fe–CoNiP coating on the spirulina were fabricated. • The permittivity and permeability increased as CIPs coated. • The Fe material enhanced the electromagnetic property. • The spirulina coated Fe–CoNiP was effective in 8–18 GHz.

Effect of pickling processes on the microstructure and properties of electroless Ni–P coating on Mg–7.5Li–2Zn–1Y alloy

Directory of Open Access Journals (Sweden)

Chunjie Xu

2014-12-01

Full Text Available The electroless plating Ni–P is prepared on the surface of Mg–7.5Li–2Zn–1Y alloys with different pickling processes. The microstructure and properties of Ni–P coating are investigated. The results show that the Ni–P coatings deposited using the different pickling processes have a different high phosphorus content amorphous Ni–P solid solution structure, and the Ni–P coatings exhibit higher hardness. There is higher phosphorus content of Ni–P amorphous coating using 125 g/L CrO3 and 110 ml/L HNO3 (w=68% than using 180 g/L CrO3 and 1 g/L KF during pre-treatment, and the coating structure is more compact, and the Ni–P coatings exhibit more excellent adhesion with substrate (Fc up to 22 N. The corrosion potential of Ni–P coating is improved and exhibits good corrosion resistance. As a result, Mg-7.5Li-2Zn-1Y alloy is remarkably protected by the Ni–P coating.

A Study on the Corrosion and Wear Behavior of Electrodeposited Ni-W-P Coating

Science.gov (United States)

Lee, Hung Bin; Wu, Meng Yen

2017-10-01

In this study, the tribocorrosion of electroplated Ni-W-P alloy coating (3.9 to 4.3 at. pct W and 13.1 to 14.7 at. pct P) on a cylindrical copper substrate was investigated using a block-on-ring tester. The wear and corrosion performance of the coating and their synergic effect were measured at different overpotentials. Under simple immersion corrosion conditions with an increasing overpotential from open-circuit potential to +400 mVSCE, the surface of the coating initially showed no obvious corrosion, eventually developing pitting holes that subsequently enlarged and showing the spreading of cracks. The corrosion products were a mixture of NiO, WO3, and phosphate, and the corroded surface was P-rich, porous, and less crystalline than the pristine coating. Corrosion and mechanical wear had little influence on tribocorrosion at low overpotential values. However, the synergic effect drastically became stronger at high overpotentials. The surface was full of large pitting holes and grooves. The weight loss due to the corrosion component increased linearly with the overpotential but was limited in comparison with the wear component, which was the main cause of weight loss. On the other hand, the friction coefficient first increased and then decreased with an increase in overpotential. Both the surface morphology of the corroded coating and the thickness of the corrosion oxide play important roles in this friction characteristic.

Microwave absorption property of the diatomite coated by Fe-CoNiP films

Science.gov (United States)

Yan, Zhenqiang; Cai, Jun; Xu, Yonggang; Zhang, Deyuan

2015-08-01

A bio-absorbent of Fe-CoNiP coated on the diatomite was fabricated by way of electroless plating of CoNiP and subsequent chemical vapor deposition of Fe. The surface morphology and composition of the above-mentioned diatomite particles at different stage were characterized with the scanning electron microscopy and the energy spectrum analysis respectively, and the results showed that the diatomite was successfully coated with CoNoP and Fe (carbony iron). The complex permittivity and permeability of composites filled with the bio-absorbent and paraffin was measured in frequency range of 2-18 GHz, and then the microwave reflection loss (RL) and the shielding effectiveness (SE) were calculated. The results showed that the permittivity and the permeability were both enlarged as Fe films were coated onto the CoNiP-coated diatomite, which was attributed to the excellent electromagnetic property of carbonyl irons. The composites made with the Fe-CoNiP diatomite had a better absorbing property (minimum RL -11.0 dB) as well as the shielding property (maximum SE 5.6 dB) at thickness 2 mm. It indicated the absorption property was mainly due to the attenuation on the microwave, and the Fe-CoNiP diatomite could be an effective absorbent with low-density.

Microstructure, soft magnetic properties and applications of amorphous Fe-Co-Si-B-Mo-P alloy

Science.gov (United States)

Hasiak, Mariusz; Miglierini, Marcel; Łukiewski, Mirosław; Łaszcz, Amadeusz; Bujdoš, Marek

2018-05-01

DC thermomagnetic properties of Fe51Co12Si16B8Mo5P8 amorphous alloy in the as-quenched and after annealing below crystallization temperature are investigated. They are related to deviations in the microstructure as revealed by Mössbauer spectrometry. Study of AC magnetic properties, i.e. hysteresis loops, relative permeability and core losses versus maximum induction was aimed at obtaining optimal initial parameters for simulation process of a resonant transformer for a rail power supply converter. The results obtained from numerical analyses including core losses, winding losses, core mass, and dimensions were compared with the same parameters calculated for Fe-Si alloy and ferrite. Moreover, Steinmetz coefficients were also calculated for the as-quenched Fe51Co12Si16B8Mo5P8 amorphous alloy.

Microstructure, soft magnetic properties and applications of amorphous Fe-Co-Si-B-Mo-P alloy

Directory of Open Access Journals (Sweden)

Mariusz Hasiak

2018-05-01

Full Text Available DC thermomagnetic properties of Fe51Co12Si16B8Mo5P8 amorphous alloy in the as-quenched and after annealing below crystallization temperature are investigated. They are related to deviations in the microstructure as revealed by Mössbauer spectrometry. Study of AC magnetic properties, i.e. hysteresis loops, relative permeability and core losses versus maximum induction was aimed at obtaining optimal initial parameters for simulation process of a resonant transformer for a rail power supply converter. The results obtained from numerical analyses including core losses, winding losses, core mass, and dimensions were compared with the same parameters calculated for Fe-Si alloy and ferrite. Moreover, Steinmetz coefficients were also calculated for the as-quenched Fe51Co12Si16B8Mo5P8 amorphous alloy.

Synthesis and densification of Cu-coated Ni-based amorphous composite powders

International Nuclear Information System (INIS)

Kim, Yong-Jin; Kim, Byoung-Kee; Kim, Jin-Chun

2007-01-01

Spherical Ni 57 Zr 20 Ti 16 Si 2 Sn 3 (numbers indicate at.%) amorphous powders were produced by the gas atomization process, and ductile Cu phase was coated on the Ni-based amorphous powders by the spray drying process in order to increase the ductility of the consolidated amorphous alloy. The characteristics of the as-prepared powders and the consolidation behaviors of Cu-coated Ni-based amorphous composite powders were investigated. The atomization was conducted at 1450 deg. C under the vacuum of 10 -2 mbar. The Ni-based amorphous powders and Cu nitrate solution were mixed and sprayed at temperature of 130 deg. C. After spray drying and reduction treatment, the sub-micron size Cu powders were coated successfully on the surface of the atomized Ni amorphous powders. The spark plasma sintering process was applied to study the densification behavior of the Cu-coated composite powders. Thickness of the Cu layer was less than 1 μm. The compacts obtained by SPS showed high relative density of over 98% and its hardness was over 800 Hv

Coatings synthesised by the pulsed laser ablation of a B{sub 4}C/W{sub 2}B{sub 5} ceramic composite

Energy Technology Data Exchange (ETDEWEB)

Tadadjeu Sokeng, I., E-mail: ifriky@tlabs.ac.za [Department of Electrical, Electronics and Computer Engineering, French South African Institute of Technology/Cape Peninsula University of Technology, Bellville campus, PO Box 1906, Bellville, 7530 (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure Road, 7129, PO Box 722, Somerset West, Western Cape Province (South Africa); UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology, College of Graduate Studies, University of South Africa (UNISA), Muckleneuk Ridge, PO Box 392, Pretoria (South Africa); Ngom, B.D. [Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure Road, 7129, PO Box 722, Somerset West, Western Cape Province (South Africa); UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology, College of Graduate Studies, University of South Africa (UNISA), Muckleneuk Ridge, PO Box 392, Pretoria (South Africa); Laboratoire de Photonique et de Nanofrabrication, Groupes de physique du Solide et Sciences des Matriaux (GPSSM), Facult des sciences et Techniques Universit Cheikh Anta Diop de Dakar (UCAD), B.P. 25114 Dakar, Fann Dakar (Senegal); Msimanga, M. [iThemba LABS Gauten, Private Bag 11, WITS 2050 Johannesburg (South Africa); Nuru, Z.Y.; Kotsedi, L.; Maaza, M. [Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure Road, 7129, PO Box 722, Somerset West, Western Cape Province (South Africa); UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology, College of Graduate Studies, University of South Africa (UNISA), Muckleneuk Ridge, PO Box 392, Pretoria (South Africa); Van Zyl, R.R. [Department of Electrical, Electronics and Computer Engineering, French South African Institute of Technology/Cape Peninsula University of Technology, Bellville campus, PO Box 1906, Bellville, 7530 (South Africa)

2015-10-30

A pellet of B{sub 4}C/W{sub 2}B{sub 5} ceramic composite was characterised and subjected to pulsed laser ablation for the deposition of coatings on corning glass substrates. We reports an attempt to produce coatings from B{sub 4}C/W{sub 2}B{sub 5} by pulsed laser deposition (PLD). The thermal, electric and mechanical properties of B{sub 4}C/W{sub 2}B{sub 5} suggest that coatings synthesised from this composite can be used for space applications. The samples were characterised using X-ray Diffraction, Atomic Force Microscopy and Heavy Ion Elastic Recoil Detection Analysis. The characterisation of the samples deposited on soda lime corning glass showed that the laser energy used in this PLD was enough to obtain non amorphous coatings formed by some alteration of the tungsten carbide crystal lattice at room temperature, and that there was no stoichiometry transfer as would be expected from PLD. The coating also showed space applicable features worth investigating. - Highlights: • B{sub 4}C/W{sub 2}B{sub 5} ceramic composite was ablated for deposition on corning glass subtrates. • Non-amorphous coating was obtained at room temperature. • There was no stoichiometry transfer as would be expected from Pulsed Laser Deposition.

Pulse electrodeposition of self-lubricating Ni–W/PTFE nanocomposite coatings on mild steel surface

Energy Technology Data Exchange (ETDEWEB)

Sangeetha, S. [Advanced Nanocomposite Coatings Laboratory, Department of Industrial Chemistry, Alagappa University, Karaikudi 630 003 (India); Kalaignan, G. Paruthimal, E-mail: pkalaignan@yahoo.com [Advanced Nanocomposite Coatings Laboratory, Department of Industrial Chemistry, Alagappa University, Karaikudi 630 003 (India); Anthuvan, J. Tennis [M. Kumarasamy College of Engineering, Karur, Tamil Nadu (India)

2015-12-30

Graphical abstract: - Highlights: • PTFE polymer inclusion on Ni–W alloy matrix was electrodeposited by pulse current method. • Tribological properties and electrochemical characterizations of the nanocomposite coatings were analyzed. • The hydrophobic behaviour of Ni–W/PTFE nanocomposite coating was measured. • Ni–W/PTFE nanocomposite coatings have showed superior tribological properties and corrosion resistance relative to that of the Ni–W alloy matrix. - Abstract: Ni–W/PTFE nanocomposite coatings with various contents of PTFE (polytetafluoroethylene) particles were prepared by pulse current (PC) electrodeposition from the Ni–W plating bath containing self lubricant PTFE particles to be co-deposited. Co-deposited PTFE particulates were uniformly distributed in the Ni–W alloy matrix. The coatings were characterized by Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Analysis (EDAX), X-ray Diffractometry (XRD) and Vicker's micro hardness tester. Tafel Polarization and electrochemical Impedance methods were used to evaluate the corrosion resistance behaviour of the nanocomposite coatings in 3.5% NaCl solution. It was found that, the Ni–W/PTFE nanocomposite coating has better corrosion resistance than the Ni–W alloy coating. Surface roughness and friction coefficient of the coated samples were assessed by Mitutoyo Surftest SJ-310 (ISO1997) and Scratch tester TR-101-M4 respectively. The contact angle (CA) of a water droplet on the surface of nanocomposite coating was measured by Optical Contact Goniometry (OCA 35). These results indicated that, the addition of PTFE in the Ni–W alloy matrix has resulted moderate microhardness, smooth surface, less friction coefficient, excellent water repellency and enhanced corrosion resistance of the nanocomposite coatings.

Characterization of Ta–Si–N coatings prepared using direct current magnetron co-sputtering

Energy Technology Data Exchange (ETDEWEB)

Chen, Yung-I, E-mail: yichen@mail.ntou.edu.tw; Lin, Kun-Yi; Wang, Hsiu-Hui; Cheng, Yu-Ru

2014-06-01

Ta–Si–N coatings were prepared using reactive direct current magnetron co-sputtering on silicon substrates. When the sputtering powers and N{sub 2} flow ratio were varied, Ta–Si–N coatings exhibited various chemical compositions and crystalline characteristics. The high-Si-content Ta–Si–N coatings exhibited an amorphous phase in the as-deposited states, whereas the low-Si-content coatings exhibited a face-centered cubic phase or an amorphous phase depending on the N content. This study evaluated the application of amorphous Ta–Si–N coatings, such as the protective coatings on glass molding dies, in high-temperature and oxygen-containing atmospheres for longed operation durations. To explore the oxidation resistance and mechanical properties of the Ta–Si–N coatings, annealing treatments were conducted in a 1%O{sub 2}–99%Ar atmosphere at 600 °C for 4–100 h. The material characteristics and oxidation behavior of the annealed Ta–Si–N coatings were examined using atomic force microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and a nanoindentation tester. The Si oxidized preferentially in the Ta–Si–N coatings. The in-diffusion of oxygen during 600 °C annealing was restricted by the formation of an amorphous oxide scale consisting of Si and O.

Moessbauer spectroscopy studies of spin reorientations in amorphous and crystalline (Co0.2Fe0.8)72.5Si12.5B15 glass coated micro-wires

International Nuclear Information System (INIS)

Nowik, I.; Felner, I.; Garcia-Miquel, H.

2007-01-01

Thermo-gravimetric, differential scanning calorimetry and comprehensive 57 Fe Moessbauer spectroscopy studies of amorphous and crystalline ferromagnetic glass coated (Co 0.2 Fe 0.8 ) 72.5 Si 12.5 B 15 micro-wires have been recorded. The Curie temperature of the amorphous phase is T C (amorp) ∼730 K. The analysis of the Moessbauer spectra reveals that below 623 K the easy axis of the magnetization is axial-along the wires, and that a tangential or/and radial orientation occurs at higher temperatures. At 770 K, in the first 4 hours the Moessbauer spectrum exhibits a pure paramagnetic doublet. Crystallization and decomposition to predominantly α-Fe(Si) and Fe 2 B occurs either by raising the temperature above 835 K or isothermally in time at lower temperatures. Annealing for a day at 770 K, leads to crystallization. In the crystalline material the magnetic moments have a complete random orientation. After cooling back to ambient temperature, both α-Fe(Si) and Fe 2 B in the glass coated wire show pure axial magnetic orientation like in the original amorphous state. The observed spin reorientations are associated with changes in the stress induced by the glass coating

Crystalline-to-amorphous phase transformation in mechanically alloyed Fe50W50 powders

International Nuclear Information System (INIS)

Sherif El-Eskandarany, M.S.; Sumiyama, K.; Suzuki, K.

1997-01-01

A mechanical alloying process via a ball milling technique has been applied for preparing amorphous Fe 50 W 50 alloy powders. The results have shown that during the first and second stages of milling (0 to 360 ks) W atoms emigrate to Fe lattices to form nanocrystalline b.c.c. Fe-W solid solution, with a grain size of about 7 nm in diameter. After 720 ks of the milling time, this solid solution was transformed to an amorphous Fe-W alloy coexisting with the residual fraction of the unprocessed W powders. During the last stage of milling (720 to 1,440 ks) all of this residual W powder reacts with the amorphous phase to form a homogeneous Fe 50 W 50 amorphous alloy. The crystallization temperature and the enthalpy change of crystallization of amorphous Fe 50 W 50 powders milled for 1,440 ks were measured to be 860 K and -9kJ/mol, respectively. The amorphous Fe 50 W 50 powder produced is almost paramagnetic at room temperature. The powder comprises homogeneous and smooth spheres with an average size of about 0.5 microm in diameter

Recent advances in co-amorphous drug formulations

DEFF Research Database (Denmark)

Dengale, Swapnil Jayant; Grohganz, Holger; Rades, Thomas

2016-01-01

with other amorphous stabilization techniques. Because of this, several research groups started to investigate the co-amorphous formulation approach, resulting in an increasing amount of scientific publications over the last few years. This study provides an overview of the co-amorphous field and its recent......Co-amorphous drug delivery systems have recently gained considerable interest in the pharmaceutical field because of their potential to improve oral bioavailability of poorly water-soluble drugs through drug dissolution enhancement as a result of the amorphous nature of the material. A co...... findings. In particular, we investigate co-amorphous formulations from the viewpoint of solid dispersions, describe their formation and mechanism of stabilization, study their impact on dissolution and in vivo performance and briefly outline the future potentials....

Hollow Co2P nanoflowers assembled from nanorods for ultralong cycle-life supercapacitors.

Science.gov (United States)

Cheng, Ming; Fan, Hongsheng; Xu, Yingying; Wang, Rongming; Zhang, Xixiang

2017-09-28

Hollow Co 2 P nanoflowers (Co 2 P HNFs) were successfully prepared via a one-step, template-free method. Microstructure analysis reveals that Co 2 P HNFs are assembled from nanorods and possess abundant mesopores and an amorphous carbon shell. Density functional theory calculations and electrochemical measurements demonstrate the high electrical conductivity of Co 2 P. Benefiting from the unique nanostructures, when employed as an electrode material for supercapacitors, Co 2 P HNFs exhibit a high specific capacitance, an outstanding rate capability, and an ultralong cycling stability. Furthermore, the constructed Co 2 P HNF//AC ASC exhibits a high energy density of 30.5 W h kg -1 at a power density of 850 W kg -1 , along with a superior cycling performance (108.0% specific capacitance retained after 10 000 cycles at 5 A g -1 ). These impressive results make Co 2 P HNFs a promising candidate for supercapacitor applications.

Influences of carbon content and coating carbon thickness on properties of amorphous CoSnO3@C composites as anode materials for lithium-ion batteries

Science.gov (United States)

Fan, Fuqiang; Fang, Guoqing; Zhang, Ruixue; Xu, Yanhui; Zheng, Junwei; Li, Decheng

2014-08-01

A series of core-shell carbon coated amorphous CoSnO3 (CoSnO3@C) with different carbon content are synthesized. Effects of carbon content and coating carbon thickness on the physical and electrochemical performances of the samples were studied in detail. The samples were analyzed by X-ray diffraction (XRD), transmission electron microscopy (TEM), thermal gravimetric analysis (TGA), galvanostatic charge-discharge and AC impedance spectroscopy, respectively. The results indicate that controlling the concentration of aqueous glucose solution influences the generation of in-situ carbon layer thickness. The optimal concentration of aqueous glucose solution, carbon content and carbon layer thickness are suggested as 0.25 M, 35.1% and 20 nm, respectively. CoSnO3@C composite prepared under the optimal conditions exhibits excellent cycling performance, whose reversible capacity could reach 491 mA h g-1 after 100 cycles.

Microstructure and physical properties of laser Zn modified amorphous-nanocrystalline coating on a titanium alloy

Science.gov (United States)

Li, Jia-Ning; Gong, Shui-Li; Shi, Yi-Ning; Suo, Hong-Bo; Wang, Xi-Chang; Deng, Yun-Hua; Shan, Fei-Hu; Li, Jian-Quan

2014-02-01

A Zn modified amorphous-nanocrystalline coating was fabricated on a Ti-6Al-4V alloy by laser cladding of the Co-Ti-B4C-Zn-Y2O3 mixed powders. Such coating was researched by means of a scanning electron microscope (SEM) and a high resolution transmission electron microscope (HRTEM), etc. Experimental results indicated that the Co5Zn21 and TiB2 nanocrystalline phases were produced through in situ metallurgical reactions, which blocked the motion of dislocation, and TiB2 grew along (010), (111) and (024). The Co5Zn21 nanocrystals were produced attached to the ceramics, which mainly consisted of the Co nanoparticles embedded in a heterogeneous zinc, and had varied crystalline orientations.

Enhanced Physical Stability of Amorphous Drug Formulations via Dry Polymer Coating.

Science.gov (United States)

Capece, Maxx; Davé, Rajesh

2015-06-01

Although amorphous solid drug formulations may be advantageous for enhancing the bioavailability of poorly soluble active pharmaceutical ingredients, they exhibit poor physical stability and undergo recrystallization. To address this limitation, this study investigates stability issues associated with amorphous solids through analysis of the crystallization behavior for acetaminophen (APAP), known as a fast crystallizer, using a modified form of the Avrami equation that kinetically models both surface and bulk crystallization. It is found that surface-enhanced crystallization, occurring faster at the free surface than in the bulk, is the major impediment to the stability of amorphous APAP. It is hypothesized that a novel use of a dry-polymer-coating process referred to as mechanical-dry-polymer-coating may be used to inhibit surface crystallization and enhance stability. The proposed process, which is examined, simultaneously mills and coats amorphous solids with polymer, while avoiding solvents or solutions, which may otherwise cause stability or crystallization issues during coating. It is shown that solid dispersions of APAP (64% loading) with a small particle size (28 μm) could be prepared and coated with the polymer, carnauba wax, in a vibratory ball mill. The resulting amorphous solid was found to have excellent stability as a result of inhibition of surface crystallization. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

Antibacterial and Tribological Performance of Carbonitride Coatings Doped with W, Ti, Zr, or Cr Deposited on AISI 316L Stainless Steel

Science.gov (United States)

Yao, Sun-Hui; Su, Yen-Liang; Lai, Yu-Cheng

2017-01-01

Carbonitride (CNx) coatings have existed for several decades but are not well understood. Related studies have indicated that CNx coatings exhibit behaviors comparable to diamond-like carbon (DLC) coatings. Metal-doped CNx coatings are expected to show superior performance to single CNx coatings. In this study, a CNx coating and a group of CNx coatings with 6 at. % metal doping (W, Ti, Zr, or Cr) were prepared on biograde AISI 316L stainless steel (SS316L) substrates, and they were then characterized and studied for antibacterial and wear performance. The microstructure, constituent phase, nanohardness, adhesion, surface roughness, and contact angle were evaluated. The antimicrobial test used Staphylococcus aureus and followed the Japanese Industrial Standard JIS Z 2801:2010. Finally, the wear behavior was assessed. The results showed that the CNx coating was a composite of amorphous CNx and amorphous C structures. The metal doping caused crystalline metal carbides/nitrides to form in the CNx coatings, which weakened their overall integrity. All the coatings showed antimicrobial ability for the SS316L samples. The CNx-Zr coating, the surface of which had the highest hydrophilicity, produced the best antibacterial performance. However, the CNx-Zr coating showed lower wear resistance than the CNx-W and CNx-Ti coatings. The CNx-Ti coating with a highly hydrophilic surface exhibited the lowest antibacterial ability. PMID:29039782

Antibacterial and Tribological Performance of Carbonitride Coatings Doped with W, Ti, Zr, or Cr Deposited on AISI 316L Stainless Steel

Directory of Open Access Journals (Sweden)

Sun-Hui Yao

2017-10-01

Full Text Available Carbonitride (CNx coatings have existed for several decades but are not well understood. Related studies have indicated that CNx coatings exhibit behaviors comparable to diamond-like carbon (DLC coatings. Metal-doped CNx coatings are expected to show superior performance to single CNx coatings. In this study, a CNx coating and a group of CNx coatings with 6 at. % metal doping (W, Ti, Zr, or Cr were prepared on biograde AISI 316L stainless steel (SS316L substrates, and they were then characterized and studied for antibacterial and wear performance. The microstructure, constituent phase, nanohardness, adhesion, surface roughness, and contact angle were evaluated. The antimicrobial test used Staphylococcus aureus and followed the Japanese Industrial Standard JIS Z 2801:2010. Finally, the wear behavior was assessed. The results showed that the CNx coating was a composite of amorphous CNx and amorphous C structures. The metal doping caused crystalline metal carbides/nitrides to form in the CNx coatings, which weakened their overall integrity. All the coatings showed antimicrobial ability for the SS316L samples. The CNx-Zr coating, the surface of which had the highest hydrophilicity, produced the best antibacterial performance. However, the CNx-Zr coating showed lower wear resistance than the CNx-W and CNx-Ti coatings. The CNx-Ti coating with a highly hydrophilic surface exhibited the lowest antibacterial ability.

Electrochemical synthesis, structure and phase composition of nano structured amorphous thin layers of NiW and Ni-Mo

International Nuclear Information System (INIS)

Vitina, I.; Lubane, M.; Belmane, V.; Rubene, V.; Krumina, A.

2006-01-01

Full text: Nano structured Ni-W thin layers containing W 6-37 wt.% were electrodeposited on a copper substratum. The W content in the layer changes, and it is determined by the electrolyte pH in the range 8.0-9.6 and the cathode current density in the range 1.0-10.0 A/dm 2 . The atomic composition and thermal stability of structure of the electrodeposited thin layers depend for the most part on the conditions of the electrodeposition and less on the W content in the layer. Cracking of the Ni-W layers electrodeposited at the electrolyte pH 8.5 and containing 34-37 wt.% W and 8.5 wt.% W was observed. The cracking increases at heating at 400 deg C for 50 h. On the contrary, no cracking of the Ni-W layer electrodeposited at the electrolyte pH 9.0 and containing 25 wt.% W was observed. The atomic composition of the layer remains practically unchanged at heating at 400 deg C for 50 h. The layer binds oxygen up to 7 wt.%. According to X-ray diffraction, in spite of the W content 35-37 wt.% in the layer, nano structured layers rather than amorphous layers were obtained which at heating at 400 deg C depending on the W content crystallises as Ni or intermetallic compounds Ni x W y if the W content is approx. 25 wt.%. Amorphous Ni-Mo alloys containing 35-52 wt.% Mo was electrodeposited on copper substratum at the cathode current densities of 0.5-1.5 A/dm2 and the electrolyte pH 6.8-8.6. Formation of thin layer (∼1-2μm) of X-ray amorphous Ni-Mo alloy, the Mo content, the characteristics of structure depend on the electrodeposition process, the electrolyte pH, and the cathode current density. The Ni-Mo layer deposited at the electrolyte pH above 8.6 and below average 6.8 had a nanocrystalline structure rather than characteristics of amorphous structure. Ni- W and Ni-Mo alloys were electrodeposited from citrate electrolyte not containing ammonium ions

Deuterium permeation of amorphous alumina coating on 316L prepared by MOCVD

International Nuclear Information System (INIS)

Li Shuai; He Di; Liu Xiaopeng; Wang Shumao; Jiang Lijun

2012-01-01

Highlights: ► Deuterium permeation behavior of alumina coating by MOCVD is investigated. ► The as-prepared alumina is amorphous. ► The alumina coating is dense and well adherent to substrate. ► Deuterium permeation rate of alumina coating is 2–3 orders of magnitude lower than martensitic steels. - Abstract: The deuterium permeation behavior of the alumina coating on 316L stainless steel prepared by metal organic chemical vapor deposition (MOCVD) was investigated. The alumina coating was also characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and scanning electron microscope (SEM). It was found that the as-prepared coating consisted of amorphous alumina. This alumina coating had a dense, crack-free and homogeneous morphology. Although the alumina coating was amorphous, effective suppression of deuterium permeation was demonstrated. The deuterium permeability of the alumina coating was 51–60 times less than that of the 316L stainless steel and 153–335 times less than that of the referred low activation martensitic steels at 860–960 K.

Influences of carbon content and coating carbon thickness on properties of amorphous CoSnO3@C composites as anode materials for lithium-ion batteries

International Nuclear Information System (INIS)

Fan, Fuqiang; Fang, Guoqing; Zhang, Ruixue; Xu, Yanhui; Zheng, Junwei; Li, Decheng

2014-01-01

Highlights: • The thickness of carbon coating layers can be successfully controlled through varying molar concentration of aqueous glucose solution. • Coating carbon thickness and carbon content are two important factors on the electrochemical performances of CoSnO3@C. • CoSnO 3 @C under optimized conditions exhibits the optimal balance between the volume buffering effect and reversible capacity. • As-prepared CoSnO 3 @C under optimized conditions shows excellent electrochemical performances, whose reversible capacity could reach 491 mA h g −1 after 100 cycles. - Abstract: A series of core–shell carbon coated amorphous CoSnO 3 (CoSnO 3 @C) with different carbon content are synthesized. Effects of carbon content and coating carbon thickness on the physical and electrochemical performances of the samples were studied in detail. The samples were analyzed by X-ray diffraction (XRD), transmission electron microscopy (TEM), thermal gravimetric analysis (TGA), galvanostatic charge–discharge and AC impedance spectroscopy, respectively. The results indicate that controlling the concentration of aqueous glucose solution influences the generation of in-situ carbon layer thickness. The optimal concentration of aqueous glucose solution, carbon content and carbon layer thickness are suggested as 0.25 M, 35.1% and 20 nm, respectively. CoSnO 3 @C composite prepared under the optimal conditions exhibits excellent cycling performance, whose reversible capacity could reach 491 mA h g −1 after 100 cycles

Preparation and characterization of spray-dried co-amorphous drug-amino acid salts

DEFF Research Database (Denmark)

Jensen, Katrine Birgitte Tarp; Blaabjerg, Lasse Ingerslev; Lenz, Elisabeth

2016-01-01

scale. In this study, spray-drying was investigated as a scale up preparation method for co-amorphous indomethacin (IND)-amino acid mixtures. In addition, the physico-chemical properties of the different co-amorphous systems were investigated with respect to the amino acids' ability towards co...... dissolution behaviour, and physical stability at various storage conditions, were examined. KEY FINDINGS: Results showed that IND could be converted into an amorphous form in combination with the amino acids arginine (ARG), histidine (HIS) and lysine (LYS) by spray-drying. Solid state characterization...... mixtures were physically stable (>10 months) at room temperature and 40°C under dry conditions. Intrinsic dissolution of the co-amorphous mixtures showed an improved dissolution behaviour under intestinal pH conditions for IND-ARG compared with the crystalline and amorphous forms of the drug. On the other...

Neutron irradiation and high temperature effects on amorphous Fe-based nano-coatings on steel - A macroscopic assessment

Science.gov (United States)

Simos, N.; Zhong, Z.; Dooryhee, E.; Ghose, S.; Gill, S.; Camino, F.; Şavklıyıldız, İ.; Akdoğan, E. K.

2017-06-01

The study revealed that loss of ductility in an amorphous Fe-alloy coating on a steel substrate composite structure was essentially prevented from occurring, following radiation with modest neutron doses of ∼2 × 1018 n/cm2. At the higher neutron dose of ∼2 × 1019, macroscopic stress-strain analysis showed that the amorphous Fe-alloy nanostructured coating, while still amorphous, experienced radiation-induced embrittlement, no longer offering protection against ductility loss in the coating-substrate composite structure. Neutron irradiation in a corrosive environment revealed exemplary oxidation/corrosion resistance of the amorphous Fe-alloy coating, which is attributed to the formation of the Fe2B phase in the coating. To establish the impact of elevated temperatures on the amorphous-to-crystalline transition in the amorphous Fe-alloy, electron microscopy was carried out which confirmed the radiation-induced suppression of crystallization in the amorphous Fe-alloy nanostructured coating.

Preparation, characterization and millimetre wave attenuation performance of carbon fibers coated with nickel-wolfram-phosphorus and nickel-cobalt-wolfram- phosphorus

International Nuclear Information System (INIS)

Ye, Mingquan; Li, Zhitao; Wang, Chen; Han, Aijun

2016-01-01

Highlights: • SEM, XRD, EDS and MMW attenuation performances of alloys coated CFs were studied. • Resistivity and P content in alloys were main factors on MMW attenuation property. • The weight gain of coated CFs has effects on the MMW attenuation performance. - Abstract: Carbon fibers (CFs) coated with Ni–X–P (X = W, Co–W or none) alloys were prepared by electroless plating. The morphology, crystal structure, and element composition of alloy-coated CFs were characterized by scanning electron microscopy, X-ray diffractometry, energy-dispersive spectrometry and microwave attenuation. The results showed that CFs were coated with a layer of alloy particles. P content in Ni–Co–W–P or Ni–W–P alloys was lower than that in Ni–P alloy, and coating alloy Ni–P was amorphous. After W or Co introduction, coating alloys exhibited crystal characteristics. MMW-attenuation performance analysis showed that the 3 mm wave attenuation performance of CFs/Ni–Co–W–P, CFs/Ni–W–P and CFs/Ni–P increased by 7.27 dBm, 4.88 dBm and 3.55 dBm, and the 8 mm wave attenuation effects increased by 11.61 dBm, 6.11 dBm, and 4.06 dBm respectively, compared with those of CFs. MMW-attenuation performance is attributable to the sample bulk resistivity and P content in the alloy. Moreover, an optimal weight gain value existed for the MMW-attenuation performance of alloy-coated CFs.

Numerically modeling Brownian thermal noise in amorphous and crystalline thin coatings

Science.gov (United States)

Lovelace, Geoffrey; Demos, Nicholas; Khan, Haroon

2018-01-01

Thermal noise is expected to be one of the noise sources limiting the astrophysical reach of Advanced LIGO (once commissioning is complete) and third-generation detectors. Adopting crystalline materials for thin, reflecting mirror coatings, rather than the amorphous coatings used in current-generation detectors, could potentially reduce thermal noise. Understanding and reducing thermal noise requires accurate theoretical models, but modeling thermal noise analytically is especially challenging with crystalline materials. Thermal noise models typically rely on the fluctuation-dissipation theorem, which relates the power spectral density of the thermal noise to an auxiliary elastic problem. In this paper, we present results from a new, open-source tool that numerically solves the auxiliary elastic problem to compute the Brownian thermal noise for both amorphous and crystalline coatings. We employ the open-source deal.ii and PETSc frameworks to solve the auxiliary elastic problem using a finite-element method, adaptive mesh refinement, and parallel processing that enables us to use high resolutions capable of resolving the thin reflective coating. We verify numerical convergence, and by running on up to hundreds of compute cores, we resolve the coating elastic energy in the auxiliary problem to approximately 0.1%. We compare with approximate analytic solutions for amorphous materials, and we verify that our solutions scale as expected with changing beam size, mirror dimensions, and coating thickness. Finally, we model the crystalline coating thermal noise in an experiment reported by Cole et al (2013 Nat. Photon. 7 644–50), comparing our results to a simpler numerical calculation that treats the coating as an ‘effectively amorphous’ material. We find that treating the coating as a cubic crystal instead of as an effectively amorphous material increases the thermal noise by about 3%. Our results are a step toward better understanding and reducing thermal noise to

Omni-directional selective shielding material based on amorphous glass coated microwires.

Science.gov (United States)

Ababei, G; Chiriac, H; David, V; Dafinescu, V; Nica, I

2012-01-01

The shielding effectiveness of the omni-directional selective shielding material based on CoFe-glass coated amorphous wires in 0.8 GHz-3 GHz microwave frequency range is investigated. The measurements were done in a controlled medium using a TEM cell and in the free space using horn antennas, respectively. Experimental results indicate that the composite shielding material can be developed with desired shielding effectiveness and selective absorption of the microwave frequency range by controlling the number of the layers and the length of microwires.

Influences of carbon content and coating carbon thickness on properties of amorphous CoSnO{sub 3}@C composites as anode materials for lithium-ion batteries

Energy Technology Data Exchange (ETDEWEB)

Fan, Fuqiang [Key Laboratory of Lithium Battery Materials of Jiangsu Province, Institute of chemical power sources, Soochow University, Suzhou 215006 (China); Fang, Guoqing [Key Laboratory of Lithium Battery Materials of Jiangsu Province, Institute of chemical power sources, Soochow University, Suzhou 215006 (China); Changzhou Institute of Energy Storage Materials and Devices, Changzhou 213000 (China); Zhang, Ruixue [Key Laboratory of Lithium Battery Materials of Jiangsu Province, Institute of chemical power sources, Soochow University, Suzhou 215006 (China); Xu, Yanhui; Zheng, Junwei [Key Laboratory of Lithium Battery Materials of Jiangsu Province, Institute of chemical power sources, Soochow University, Suzhou 215006 (China); College of Physics, Optoelectronics and Energy, Soochow University, Suzhou 215006 (China); Li, Decheng, E-mail: lidecheng@suda.edu.cn [Key Laboratory of Lithium Battery Materials of Jiangsu Province, Institute of chemical power sources, Soochow University, Suzhou 215006 (China); College of Physics, Optoelectronics and Energy, Soochow University, Suzhou 215006 (China)

2014-08-30

Highlights: • The thickness of carbon coating layers can be successfully controlled through varying molar concentration of aqueous glucose solution. • Coating carbon thickness and carbon content are two important factors on the electrochemical performances of CoSnO3@C. • CoSnO{sub 3}@C under optimized conditions exhibits the optimal balance between the volume buffering effect and reversible capacity. • As-prepared CoSnO{sub 3}@C under optimized conditions shows excellent electrochemical performances, whose reversible capacity could reach 491 mA h g{sup −1} after 100 cycles. - Abstract: A series of core–shell carbon coated amorphous CoSnO{sub 3} (CoSnO{sub 3}@C) with different carbon content are synthesized. Effects of carbon content and coating carbon thickness on the physical and electrochemical performances of the samples were studied in detail. The samples were analyzed by X-ray diffraction (XRD), transmission electron microscopy (TEM), thermal gravimetric analysis (TGA), galvanostatic charge–discharge and AC impedance spectroscopy, respectively. The results indicate that controlling the concentration of aqueous glucose solution influences the generation of in-situ carbon layer thickness. The optimal concentration of aqueous glucose solution, carbon content and carbon layer thickness are suggested as 0.25 M, 35.1% and 20 nm, respectively. CoSnO{sub 3}@C composite prepared under the optimal conditions exhibits excellent cycling performance, whose reversible capacity could reach 491 mA h g{sup −1} after 100 cycles.

Synthesis of Fe-based amorphous composite coatings with low purity materials by laser cladding

Energy Technology Data Exchange (ETDEWEB)

Zhu Qingjun [School of Materials Science and Engineering, Shandong University, Jinan 250061 (China)]. E-mail: sduzhu@yahoo.com.cn; Qu Shiyao [School of Materials Science and Engineering, Shandong University, Jinan 250061 (China); Wang Xinhong [School of Materials Science and Engineering, Shandong University, Jinan 250061 (China); Zou Zengda [School of Materials Science and Engineering, Shandong University, Jinan 250061 (China)

2007-06-30

Amorphous composite coatings Fe{sub 38}Ni{sub 30-X}Si{sub 16}B{sub 14}V{sub 2}M {sub X} (X = 0, 1, 2) (M contains Al, Ti, Mo, and C) were prepared with low purity of raw materials by laser cladding. X-ray diffraction and transmission electron microscopy results show that the coating have an amorphous structure with a few crystalline phase on it. The amorphous phase is the primary phase. The glass forming ability as well as the microhardness of the Fe-based alloy made from low purity raw materials can be much enhanced by adding small amount of multi-components. However, the elements addition has its optimal quantity. When X is equal to 1, the microstructure of the coating contains 97.93% amorphous phase and 2.07% crystalline phase on it. As a result, the microhardness of the coating reaches maximum. With further increasing of the additions, the amorphous phase in the coating lessens instead of augment and the crystalline phase begins to accumulate, which result in the decrease of the microhardness.

Deuterium permeation of amorphous alumina coating on 316L prepared by MOCVD

Science.gov (United States)

Li, Shuai; He, Di; Liu, Xiaopeng; Wang, Shumao; Jiang, Lijun

2012-01-01

The deuterium permeation behavior of the alumina coating on 316L stainless steel prepared by metal organic chemical vapor deposition (MOCVD) was investigated. The alumina coating was also characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and scanning electron microscope (SEM). It was found that the as-prepared coating consisted of amorphous alumina. This alumina coating had a dense, crack-free and homogeneous morphology. Although the alumina coating was amorphous, effective suppression of deuterium permeation was demonstrated. The deuterium permeability of the alumina coating was 51-60 times less than that of the 316L stainless steel and 153-335 times less than that of the referred low activation martensitic steels at 860-960 K.

Study on the nano-composite electroless coating of Ni-P/Ag

International Nuclear Information System (INIS)

Ma Hongfang; Tian Fang; Li Dan; Guo Qiang

2009-01-01

The nano-composite coating of Ni-P/Ag was obtained by adding silver nanoparticles to the Ni-P electroless plating solutions. The properties of the coating were tested by scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), differential scanning calorimeter (DSC), X-ray diffraction (XRD) and microsclerometer. Silver nanoparticles changed the properties of the composite coating. The Ni-P electroless coating contains 12.23 wt.% P while the composite coating of Ni-P/Ag contains 11.17 wt.% P and 0.24 wt.% Ag. The hardness of the composite coating is bigger than that of Ni-P alloy coating. Differential scanning calorimeter studies showed the amorphous to crystalline transition with precipitation of Ni 3 P and Ni around 335 deg. C

Acceleration of aneurysm healing by P(DLLA-co-TMC)-coated coils enabling the controlled release of vascular endothelial growth factor

International Nuclear Information System (INIS)

Wang, Qiujing; Gao, Yuyuan; Sun, Xinlin; Ji, Bin; Cui, Xubo; Liu, Yaqi; Zheng, Tao; Chen, Chengwei; Jiang, Xiaodan; Zhu, Aiping; Quan, Daping

2014-01-01

Since the introduction of the detachable coil in endovascular treatment of intracranial aneurysms, the in-hospital mortality rate has been significantly decreased. Recurrence of the aneurysm remains the major drawback of using detachable coils. We prepared a bioactive coil coated with poly(d,l-lactide)-7co-(1,3-trimethylene carbonate) (P(DLLA-co-TMC)), a novel copolymer for controlling the release of vascular endothelial growth factor (VEGF). Platinum coils were prepared by successive coating with cationic P(DLLA-co-TMC) and anionic heparin. Then, recombinant human VEGF-165 (rhVEGF) was immobilized by affinity binding to heparin. The morphological characteristics and sustained in vitro release of rhVEGF were examined using scanning electron microscopy and enzyme-linked immunosorbent assay, respectively. The efficacy of these novel coils modified by P(DLLA-co-TMC)/rhVEGF was tested using a common carotid artery aneurysm model in rats. Experimental aneurysms were embolized with unmodified, P(DLLA-co-TMC)/heparin-coated or P(DLLA-co-TMC)/rhVEGF-coated platinum coils (n = 18). The coils were removed on days 15, 30 and 90 after insertion, and the histological and immunohistochemical analysis of factor VIII was performed to confirm the presence of endothelial cells in the organized area. In addition, the controlled in vivo release of VEGF was confirmed by Western blotting analysis. The release of VEGF tended to increase during the whole period and no burst release was observed. In the group treated with P(DLLA-co-TMC)/rhVEGF-coated platinum coils, clot organization and endothelial cell proliferation were accelerated. The immunohistochemistry study showed that the expression of factor VIII was found in the P(DLLA-co-TMC)/rhVEGF-coated coil group but not in the other two groups. Furthermore, Western blotting analysis confirmed that the major released VEGF in the aneurysm sac was from the P(DLLA-co-TMC)/VEGF-coated coil. P(DLLA-co-TMC)/rhVEGF-coated platinum coils can

Neutron irradiation and high temperature effects on amorphous Fe-based nano-coatings on steel – A macroscopic assessment

International Nuclear Information System (INIS)

Simos, N.; Zhong, Z.; Dooryhee, E.; Ghose, S.; Gill, S.

2017-01-01

Here, this study revealed that loss of ductility in an amorphous Fe-alloy coating on a steel substrate composite structure was essentially prevented from occurring, following radiation with modest neutron doses of ~2 x 10 18 n/cm 2 . At the higher neutron dose of ~2 x 10 19 , macroscopic stress-strain analysis showed that the amorphous Fe-alloy nanostructured coating, while still amorphous, experienced radiation-induced embrittlement, no longer offering protection against ductility loss in the coating-substrate composite structure. Neutron irradiation in a corrosive environment revealed exemplary oxidation/corrosion resistance of the amorphous Fe-alloy coating, which is attributed to the formation of the Fe 2 B phase in the coating. To establish the impact of elevated temperatures on the amorphous-to-crystalline transition in the amorphous Fe-alloy, electron microscopy was carried out which confirmed the radiation-induced suppression of crystallization in the amorphous Fe-alloy nanostructured coating.

Crystal structure of (OC5W(μ-dppeW(CO5

Directory of Open Access Journals (Sweden)

Hannah F. Drake

2016-10-01

Full Text Available The centrosymmetric title complex, [μ-ethane-1,2-diylbis(diphenylphosphane-κ2P:P′]bis[pentacarbonyltungsten(0], [W2(C26H24P2(CO10], consists of two W(CO5 moieties bridged by a bis(diphenylphosphanylethane (dppe ligand. The W0 atom has a slightly distorted octahedral coordination environment consisting of 5 carbonyl ligands and one P atom from the bridging dppe ligand with the nearest W0 atom 5.625 (5 Å away. The complex resides on a center of symmetry.

Study of carbide-forming element interlayers for diamond nucleation and growth on silicon and WC-Co substrates

International Nuclear Information System (INIS)

Tang, Y.; Li, Y.S.; Yang, Q.; Hirose, A.

2010-01-01

Diamond nucleation and growth on several typical carbide-forming elements (CFE) (Ti, Cr and W) coated Si and WC-Co substrates were studied. The ion beam sputtered CFE interlayers show an amorphous/nanocrystalline microstructure. The diamond formed on the CFE coated substrates shows higher nucleation density and rate and finer grain structure than on uncoated substrates. Consequently, nanocrystalline diamond thin films can be formed on the CFE coated substrates under conventional microcrystalline diamond growth conditions. Among the three tested CFE interlayers, diamond has the highest nucleation density and rate on W layer and the lowest on Ti layer. The diamond nucleation density and rate on CFE coated WC-Co are much higher than those on widely used metal nitride coated WC-Co.

Corrosion and wear protective composition modulated alloy coatings based on ternary Ni-P-X alloys

DEFF Research Database (Denmark)

Leisner, P.; Benzon, M. E.; Christoffersen, Lasse

1996-01-01

Scattered reporting in the litterature describes a number of ternary Ni-P-X alloyes (where X can be Co, Cr, Cu, Mo, Pd, Re or W) with promising corrosin and wear protective performance. Based on a systematic study of Ni-P-X alloys it is the intention to produce coatings with improved corrosion...... and wear performance compared with conventional coatings like electroless nickel, hard chromioum and anodised aluminium....

Effect of amorphous fluorinated coatings on photocatalytic properties of anodized titanium surfaces

Energy Technology Data Exchange (ETDEWEB)

Persico, Federico [Dipartimento di Chimica, Materiali e Ingegneria Chimica “Giulio Natta”, Politecnico di Milano, via Mancinelli 7, 20131, Milano (Italy); Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali, Via G. Giusti, 9, 50121 Firenze (Italy); Sansotera, Maurizio, E-mail: maurizio.sansotera@polimi.it [Dipartimento di Chimica, Materiali e Ingegneria Chimica “Giulio Natta”, Politecnico di Milano, via Mancinelli 7, 20131, Milano (Italy); Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali, Via G. Giusti, 9, 50121 Firenze (Italy); Diamanti, Maria Vittoria [Dipartimento di Chimica, Materiali e Ingegneria Chimica “Giulio Natta”, Politecnico di Milano, via Mancinelli 7, 20131, Milano (Italy); Magagnin, Luca; Venturini, Francesco; Navarrini, Walter [Dipartimento di Chimica, Materiali e Ingegneria Chimica “Giulio Natta”, Politecnico di Milano, via Mancinelli 7, 20131, Milano (Italy); Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali, Via G. Giusti, 9, 50121 Firenze (Italy)

2013-10-31

The photocatalytic activity promoted by anodized titanium surfaces coated with different amorphous perfluoropolymers was evaluated. A copolymer between tetrafluoroethylene and perfluoro-4-trifluoromethoxy-1,3-dioxole and two perfluoropolyethers containing ammonium phosphate and triethoxysilane functionalities, respectively, were tested as coating materials. These coatings revealed good adhesion to the anodized titanium substrate and conferred to it both hydrophobicity and oleophobicity. The photocatalytic activity of the coating on anodized titanium was evaluated by monitoring the degradation of stearic acid via Infrared spectroscopy. The degradation rate of stearic acid was reduced but not set to zero by the presence of the fluorinated coatings, leading to the development of advanced functional coatings. The morphological variations of the coatings as a result of photocatalysis were also determined by atomic force microscopy. - Highlights: • Coated anodized titanium surfaces show a decreased wettability. • Evaluation of the stability of perfluorinated coatings towards photocatalysis. • Amorphous perfluorinated coatings do not hinder photocatalytic activity.

Wear Resistant Amorphous and Nanocomposite Coatings

Energy Technology Data Exchange (ETDEWEB)

Racek, O

2008-03-26

Glass forming materials (critical cooling rate <10{sup 4}K.s{sup -1}) are promising for their high corrosion and wear resistance. During rapid cooling, the materials form an amorphous structure that transforms to nanocrystalline during a process of devitrification. High hardness (HV 1690) can be achieved through a controlled crystallization. Thermal spray process has been used to apply coatings, which preserves the amorphous/nanocomposite structure due to a high cooling rate of the feedstock particles during the impact on a substrate. Wear properties have been studied with respect to process conditions and feedstock material properties. Application specific properties such as sliding wear resistance have been correlated with laboratory tests based on instrumented indentation and scratch tests.

Indentation creep behavior of cold sprayed aluminum amorphous/nano-crystalline coatings

Energy Technology Data Exchange (ETDEWEB)

Babu, P. Suresh [International Advanced Research Centre for Powder Metallurgy and New Materials (ARCI), Balapur, Hyderabad 500005, Andhra Pradesh (India); Nanomechanics and Nanotribology Laboratory, Department of Mechanical and Materials Engineering, Florida International University, Miami, FL 33174 (United States); Jha, R.; Guzman, M. [Nanomechanics and Nanotribology Laboratory, Department of Mechanical and Materials Engineering, Florida International University, Miami, FL 33174 (United States); Sundararajan, G. [International Advanced Research Centre for Powder Metallurgy and New Materials (ARCI), Balapur, Hyderabad 500005, Andhra Pradesh (India); Agarwal, Arvind, E-mail: agarwala@fiu.edu [Nanomechanics and Nanotribology Laboratory, Department of Mechanical and Materials Engineering, Florida International University, Miami, FL 33174 (United States)

2016-03-21

In this study, we report room temperature creep properties of cold sprayed aluminum amorphous/nanocrystalline coating using nanoindentation technique. Creep experiments were also performed on heat treated coatings to study the structural stability and its influence on the creep behavior. The peak load and holding time were varied from 1000 to 4000 µN and 0 to 240 s respectively. Stress exponent value (n) vary from 5.6 to 2.3 in as-sprayed (AS) coatings and 7.2–4.8 in heat treated (HT) coatings at peak load of 1000–4000 µN at 240 s hold time. Higher stress exponent value indicates heat treated coatings have more resistance to creep deformation than as-sprayed coatings. Relaxed, partially crystallized structure with less porosity, and stronger inter-splat boundaries restrict the deformation in heat treated coatings as compared to greater free volume generation in amorphous as-sprayed coatings. The computed activation volume of heat treated coatings is twice of as-sprayed coatings indicating greater number of atom participation in shear band formation in heat treated coatings. The proposed mechanism was found to be consistent with the stress exponent values.

Ni-based amorphous alloy-coating for bipolar plate of PEM fuel cell by electrochemical plating

International Nuclear Information System (INIS)

Yamaura, S; Kim, S C; Inoue, A

2013-01-01

In this study, the Ni-Cr-P amorphous alloy-coated bipolar plates were produced by electro-plating on the Cu base plates with a flow field. The power generation tests of a single fuel cell with those Ni-Cr-P bipolar plates were conducted at 353 K. It was found that the single fuel cell with those Ni-Cr-P bipolar plates showed excellent I-V performance as well as that with the carbon graphite bipolar plates. It was also found that the single cell with those Ni-Cr-P bipolar plates showed better I-V performance than that with the Ni-P amorphous alloy-coated bipolar plates. Furthermore, the long-time operation test was conducted for 440 h with those Ni-Cr-P bipolar plates at the constant current density of 200 mA·cm −2 . As a result, it was found that the cell voltage gradually decreased at the beginning of the measurement before 300 h and then the voltage was kept constant after 300 h.

Preparation and characterization of amorphous SiO2 coatings deposited by mirco-arc oxidation on sintered NdFeB permanent magnets

Science.gov (United States)

Xu, J. L.; Xiao, Q. F.; Mei, D. D.; Zhong, Z. C.; Tong, Y. X.; Zheng, Y. F.; Li, L.

2017-03-01

Amorphous SiO2 coatings were prepared on sintered NdFeB magnets by micro-arc oxidation (MAO) in silicate solution. The surface and cross-sectional morphologies, element and phase composition, corrosion resistance and magnetic properties of the coatings were investigated by scanning electron microscopy (SEM), energy dispersive X-ray spectrometer (EDS), X-ray photoelectron spectroscopy (XPS), potentiodynamic polarization test and physical properties measurements system (PPMS). The results showed that the surface morphologies of the coatings exhibited the "coral reef" like structure, different from the typical MAO porous structure. With increasing the voltages, the thickness of the coatings increased from 12.72 to 19.90 μm, the content of Si element increased, while the contents of Fe, Nd and P elements decreased. The coatings were mainly composed of amorphous SiO2 and a few amorphous Fe2O3 and Nd2O3. The amorphous SiO2 coatings presented excellent thermal shock resistance, while the thermal shock resistance decreased with increasing the voltages. The corrosion resistance of the coatings increased with increasing the voltages, and it could be enhanced by one order of magnitude compared to the uncoated NdFeB magnets. The MAO coatings slightly decreased the magnetic properties of the NdFeB samples in different degrees.

Structural analysis of sputtered (W-C)1-xMx (M≡Fe,Co) films with 0≤x≤0.20

International Nuclear Information System (INIS)

Cavaleiro, A.; Trindade, B.; Vieira, M.T.

1993-01-01

Structural characterization of (W-C) 1-x M x (M≡Fe,Co) films with 0≤x≤0.20 was carried out using electron probe microanalysis (EPMA), X-ray diffraction (XRD) and transmission electron microscopy-electron diffraction (TEM-ED). The results showed that the structure of these films depends on the percentage of iron and cobalt and becomes amorphous with increasing content of these elements. The microstructure of the crystalline coatings was found to be composed of small grains of β-WC 1-x with a high number of defects. A strong β-WC 1-x [311] texture was observed for iron and cobalt contents around 5.5 at.%. The films richer in iron and cobalt showed typical amorphous XRD and ED patterns, exhibiting two broad peaks and two wide diffuse rings respectively. Moreover, bright-field analysis revealed fairly contrasted images, the structure of these films being difficult to resolve. (orig.)

The role of electrolyte pH on phase evolution and magnetic properties of CoFeW codeposited films

International Nuclear Information System (INIS)

Ghaferi, Z.; Sharafi, S.; Bahrololoom, M.E.

2016-01-01

Highlights: • Deposition tends to anomalous-induced fashion at higher pH values. • The structure of the coatings depend on electrolyte pH effectively. • Grain size of two-phase structure films is lower than single-phase solid solutions. • Coercivity of the coatings changed by tungsten content and surface defects. • The highest pH value produced coating with superior magnetic behaviour. - Abstract: In this research, nanocrystalline Co–Fe–W alloy coatings were electrodeposited from a citrate-borate bath. The influence of electrolyte pH on the morphology, microstructure and magnetic properties of these films was also studied. By increasing pH value, the amount of iron content increased from 30 to 55 wt.% which indicates anomalous fashion at higher pH electrolytes. X-ray diffraction patterns showed that the structure of these films depend on electrolyte pH effectively. However, two-phase structure coatings showed smaller average grain size compared with one- phase solid solutions. Vibrating sample magnetometer measurements indicated that the coercivity of the coatings was in the range of 21–76 Oe. However, the highest pH value produced coating with superior magnetic behaviour. Microhardness of the coatings reached its maximum value at about 260HV which is referred to the highest tungsten content.

Suspension plasma sprayed composite coating using amorphous powder feedstock

International Nuclear Information System (INIS)

Chen Dianying; Jordan, Eric H.; Gell, Maurice

2009-01-01

Al 2 O 3 -ZrO 2 composite coatings were deposited by the suspension plasma spray process using molecularly mixed amorphous powders. X-ray diffraction (XRD) analysis shows that the as-sprayed coating is composed of α-Al 2 O 3 and tetragonal ZrO 2 phases with grain sizes of 26 nm and 18 nm, respectively. The as-sprayed coating has 93% density with a hardness of 9.9 GPa. Heat treatment of the as-sprayed coating reveals that the Al 2 O 3 and ZrO 2 phases are homogeneously distributed in the composite coating

Effect of thermal spray processing techniques on the microstructure and properties of Ni-based amorphous coatings

International Nuclear Information System (INIS)

Lee, S.M.; Moon, B.M.; Fleury, E.; Ahn, H.S.; Kim, D.H.; Kim, W.T.; Sordelet, D.J.

2005-01-01

Metallic amorphous materials have been widely developed thanks to the outstanding properties including high chemical stability, mechanical strength, and magnetic properties. However, with the exception of a few compositions, the limiting factor is the critical cooling rate for the formation of the amorphous phase. For many applications, it is only the contact surface properties that are important, thus the use, of coating techniques such as thermal sprayings has several attractive features. In this paper, we present the microstructure of Ni-based amorphous coatings prepared by laser cladding and vacuum plasma spraying. The utilization of plasma spraying to deposit atomized powder enabled the formation of fully amorphous coating, laser cladding resulted in mostly crystallized structures. Glass forming ability and wear properties of the coatings were discussed as a function of the coating microstructure. (orig.)

Physical–chemical and biological behavior of an amorphous calcium phosphate thin film produced by RF-magnetron sputtering

International Nuclear Information System (INIS)

Santos, Euler A. dos; Moldovan, Simona; Mateescu, Mihaela; Faerber, Jacques; Acosta, Manuel; Pelletier, Hervé; Anselme, Karine; Werckmann, Jacques

2012-01-01

This work evaluates the thermal reactivity and the biological reactivity of an amorphous calcium phosphate thin film produced by radio frequency (RF) magnetron sputtering onto titanium substrates. The analyses showed that the sputtering conditions used in this work led to the deposition of an amorphous calcium phosphate. The thermal treatment of this amorphous coating in the presence of H 2 O and CO 2 promoted the formation of a carbonated HA crystalline coating with the entrance of CO 3 2− ions into the hydroxyl HA lattice. When immersed in culture medium, the amorphous and carbonated coatings exhibited a remarkable instability. The presence of proteins increased the dissolution process, which was confirmed by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) analyses. Moreover, the carbonated HA coating induced precipitation independently of the presence of proteins under dynamic conditions. Despite this surface instability, this reactive calcium phosphate significantly improved the cellular behavior. The cell proliferation was higher on the Ticp than on the calcium phosphate coatings, but the two coatings increased cellular spreading and stress fiber formation. In this sense, the presence of reactive calcium phosphate coatings can stimulate cellular behavior. - Highlights: ► Functionalization of Ti with reactive CaP thin film by RF-magnetron sputtering. ► De-hydroxylation facilitating the insertion of CO 3 2− into the HA lattice. ► High surface reactivity in the presence of culture medium. ► Cell behavior improved by the presence of reactive films.

Preparation and characterization of amorphous SiO2 coatings deposited by mirco-arc oxidation on sintered NdFeB permanent magnets

International Nuclear Information System (INIS)

Xu, J.L.; Xiao, Q.F.; Mei, D.D.; Zhong, Z.C.; Tong, Y.X.; Zheng, Y.F.; Li, L.

2017-01-01

Amorphous SiO 2 coatings were prepared on sintered NdFeB magnets by micro-arc oxidation (MAO) in silicate solution. The surface and cross-sectional morphologies, element and phase composition, corrosion resistance and magnetic properties of the coatings were investigated by scanning electron microscopy (SEM), energy dispersive X-ray spectrometer (EDS), X-ray photoelectron spectroscopy (XPS), potentiodynamic polarization test and physical properties measurements system (PPMS). The results showed that the surface morphologies of the coatings exhibited the “coral reef” like structure, different from the typical MAO porous structure. With increasing the voltages, the thickness of the coatings increased from 12.72 to 19.90 µm, the content of Si element increased, while the contents of Fe, Nd and P elements decreased. The coatings were mainly composed of amorphous SiO 2 and a few amorphous Fe 2 O 3 and Nd 2 O 3 . The amorphous SiO 2 coatings presented excellent thermal shock resistance, while the thermal shock resistance decreased with increasing the voltages. The corrosion resistance of the coatings increased with increasing the voltages, and it could be enhanced by one order of magnitude compared to the uncoated NdFeB magnets. The MAO coatings slightly decreased the magnetic properties of the NdFeB samples in different degrees. - Highlights: • Amorphous SiO 2 coatings were prepared on sintered NdFeB magnets by micro-arc oxidation. • The coatings presented excellent thermal shock resistance. • The corrosion resistance could be enhanced by one order of magnitude. • The MAO coatings slightly decreased the magnetic properties of the NdFeB samples.

Hollow Co2P nanoflowers organized by nanorods for ultralong cycle-life supercapacitors

KAUST Repository

Cheng, Ming

2017-08-24

Hollow Co2P nanoflowers (Co2P HNF) are successfully prepared via a one-step, template-free method. Microstructure analysis reveals that Co2P HNF is assembled by nanorods, possesses abundant mesopores and a amorphous carbon shell. Density functional theory calculation and electrochemical measurements demonstrate the high electrical conductivity of Co2P. Benefiting from the unique nanostructures, when employed as electrode material for supercapacitors, Co2P HNF exhibits a high specific capacitance, an outstanding rate capability, and an ultralong cycle stability. Furthermore,. the constructed Co2P HNF//AC ASC yields a high energy density of 30.5 Wh kg-1 at a power density of 850 W kg-1, along with an superior cycling performance (108.0% specific capacitance retained after 10000 cycles at 5 A g-1). These impressive results make Co2P HNF a promising candidate for supercapacitor applications.

Applications in the Nuclear Industry for Thermal Spray Amorphous Metal and Ceramic Coatings

Science.gov (United States)

Blink, J.; Farmer, J.; Choi, J.; Saw, C.

2009-06-01

Amorphous metal and ceramic thermal spray coatings have been developed with excellent corrosion resistance and neutron absorption. These coatings, with further development, could be cost-effective options to enhance the corrosion resistance of drip shields and waste packages, and limit nuclear criticality in canisters for the transportation, aging, and disposal of spent nuclear fuel. Iron-based amorphous metal formulations with chromium, molybdenum, and tungsten have shown the corrosion resistance believed to be necessary for such applications. Rare earth additions enable very low critical cooling rates to be achieved. The boron content of these materials and their stability at high neutron doses enable them to serve as high efficiency neutron absorbers for criticality control. Ceramic coatings may provide even greater corrosion resistance for waste package and drip shield applications, although the boron-containing amorphous metals are still favored for criticality control applications. These amorphous metal and ceramic materials have been produced as gas-atomized powders and applied as near full density, nonporous coatings with the high-velocity oxy-fuel process. This article summarizes the performance of these coatings as corrosion-resistant barriers and as neutron absorbers. This article also presents a simple cost model to quantify the economic benefits possible with these new materials.

Microstructure and Wear Resistance of Laser-Clad (Co, Ni61.2B26.2Si7.8Ta4.8 Coatings

Directory of Open Access Journals (Sweden)

Luan Zhang

2017-10-01

Full Text Available It has been reported that a quaternary Co61.2B26.2Si7.8Ta4.8 alloy is a good glass former and can be laser-clad to an amorphous composite coating with superior hardness and wear resistance. In this paper, alloys with varying Ni contents to substitute for Co are coated on the surface of #45 carbon steel using a 5-kW CO2 laser source for the purpose of obtaining protective coatings. In contrast to the quaternary case, the clad layers are characterized by a matrix of α-(Fe, Co, Ni solid solution plus CoB, Co3B, and Co3Ta types of precipitates. The cladding layer is divided into four regions: Near-surface dendrites, α-(Fe, Co, Ni solid solution plus dispersed particles in the middle zone, columnar bonding zone, and heat-affected area that consists of martensite. The hardness gradually decreases with increasing Ni content, and the maximum hardness occurs in the middle zone. Both the friction coefficient and wear volume are minimized in the alloy containing 12.2% Ni. Compared with the previous cobalt-based quaternary alloy Co61.2B26.2Si7.8Ta4.8, the addition of the Ni element reduces the glass-forming ability and henceforth the hardness and wear resistance of the clad layers.

Applications in the Nuclear Industry for Corrosion-Resistant Amorphous-Metal Thermal-Spray Coatings

International Nuclear Information System (INIS)

Farmer, J; Choi, J

2007-01-01

Amorphous metal and ceramic thermal spray coatings have been developed that can be used to enhance the corrosion resistance of containers for the transportation, aging and disposal of spent nuclear fuel and high-level radioactive wastes. Fe-based amorphous metal formulations with chromium, molybdenum and tungsten have shown the corrosion resistance believed to be necessary for such applications. Rare earth additions enable very low critical cooling rates to be achieved. The boron content of these materials, and their stability at high neutron doses, enable them to serve as high efficiency neutron absorbers for criticality control. Ceramic coatings may provide even greater corrosion resistance for container applications, though the boron-containing amorphous metals are still favored for criticality control applications. These amorphous metal and ceramic materials have been produced as gas atomized powders and applied as near full density, non-porous coatings with the high-velocity oxy-fuel process. This paper summarizes the performance of these coatings as corrosion-resistant barriers, and as neutron absorbers. Relevant corrosion models are also discussed, as well as a cost model to quantify the economic benefits possible with these new materials

Bacterial adhesion on amorphous and crystalline metal oxide coatings

International Nuclear Information System (INIS)

Almaguer-Flores, Argelia; Silva-Bermudez, Phaedra; Galicia, Rey; Rodil, Sandra E.

2015-01-01

Several studies have demonstrated the influence of surface properties (surface energy, composition and topography) of biocompatible materials on the adhesion of cells/bacteria on solid substrates; however, few have provided information about the effect of the atomic arrangement or crystallinity. Using magnetron sputtering deposition, we produced amorphous and crystalline TiO 2 and ZrO 2 coatings with controlled micro and nanoscale morphology. The effect of the structure on the physical–chemical surface properties was carefully analyzed. Then, we studied how these parameters affect the adhesion of Escherichia coli and Staphylococcus aureus. Our findings demonstrated that the nano-topography and the surface energy were significantly influenced by the coating structure. Bacterial adhesion at micro-rough (2.6 μm) surfaces was independent of the surface composition and structure, contrary to the observation in sub-micron (0.5 μm) rough surfaces, where the crystalline oxides (TiO 2 > ZrO 2 ) surfaces exhibited higher numbers of attached bacteria. Particularly, crystalline TiO 2 , which presented a predominant acidic nature, was more attractive for the adhesion of the negatively charged bacteria. The information provided by this study, where surface modifications are introduced by means of the deposition of amorphous or crystalline oxide coatings, offers a route for the rational design of implant surfaces to control or inhibit bacterial adhesion. - Highlights: • Amorphous (a) and crystalline (c) TiO 2 and ZrO 2 coatings were deposited. • The atomic ordering influences the coatings surface charge and nano-topography. • The atomic ordering modifies the bacterial adhesion for the same surface chemistry. • S. aureus adhesion was lower on a-TiO 2 and a-ZrO 2 than on their c-oxide counterpart. • E. coli adhesion on a-TiO 2 was lower than on the c-TiO 2

Bacterial adhesion on amorphous and crystalline metal oxide coatings

Energy Technology Data Exchange (ETDEWEB)

Almaguer-Flores, Argelia [Facultad de Odontología, División de Estudios de Posgrado e Investigación, Universidad Nacional Autónoma de México, Circuito exterior s/n, Ciudad Universitaria, 04510 México D.F. (Mexico); Silva-Bermudez, Phaedra, E-mail: suriel21@yahoo.com [Unidad de Ingeniería de Tejidos, Terapia Celular y Medicina Regenerativa, Instituto Nacional de Rehabilitación, Calzada México-Xochimilco No. 289, Col. Arenal de Guadalupe, 14389 México D.F. (Mexico); Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, Circuito Exterior s/n, Ciudad Universitaria, 04510 México D.F. (Mexico); Galicia, Rey; Rodil, Sandra E. [Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, Circuito Exterior s/n, Ciudad Universitaria, 04510 México D.F. (Mexico)

2015-12-01

Several studies have demonstrated the influence of surface properties (surface energy, composition and topography) of biocompatible materials on the adhesion of cells/bacteria on solid substrates; however, few have provided information about the effect of the atomic arrangement or crystallinity. Using magnetron sputtering deposition, we produced amorphous and crystalline TiO{sub 2} and ZrO{sub 2} coatings with controlled micro and nanoscale morphology. The effect of the structure on the physical–chemical surface properties was carefully analyzed. Then, we studied how these parameters affect the adhesion of Escherichia coli and Staphylococcus aureus. Our findings demonstrated that the nano-topography and the surface energy were significantly influenced by the coating structure. Bacterial adhesion at micro-rough (2.6 μm) surfaces was independent of the surface composition and structure, contrary to the observation in sub-micron (0.5 μm) rough surfaces, where the crystalline oxides (TiO{sub 2} > ZrO{sub 2}) surfaces exhibited higher numbers of attached bacteria. Particularly, crystalline TiO{sub 2}, which presented a predominant acidic nature, was more attractive for the adhesion of the negatively charged bacteria. The information provided by this study, where surface modifications are introduced by means of the deposition of amorphous or crystalline oxide coatings, offers a route for the rational design of implant surfaces to control or inhibit bacterial adhesion. - Highlights: • Amorphous (a) and crystalline (c) TiO{sub 2} and ZrO{sub 2} coatings were deposited. • The atomic ordering influences the coatings surface charge and nano-topography. • The atomic ordering modifies the bacterial adhesion for the same surface chemistry. • S. aureus adhesion was lower on a-TiO{sub 2} and a-ZrO{sub 2} than on their c-oxide counterpart. • E. coli adhesion on a-TiO{sub 2} was lower than on the c-TiO{sub 2}.

Preparation and characterization of amorphous SiO{sub 2} coatings deposited by mirco-arc oxidation on sintered NdFeB permanent magnets

Energy Technology Data Exchange (ETDEWEB)

Xu, J.L., E-mail: jlxu@nchu.edu.cn [Center for Biomedical Materials and Engineering, Harbin Engineering University, Harbin 150001 (China); School of Materials Science and Engineering, Nanchang Hangkong University, Nanchang 330063 (China); Xiao, Q.F.; Mei, D.D. [School of Materials Science and Engineering, Nanchang Hangkong University, Nanchang 330063 (China); Zhong, Z.C., E-mail: zzhong2014@sina.com [The Institute for Rare Earth Magnetic Materials and Devices, Jiangxi University of Science and Technology, Ganzhou 341000 (China); Tong, Y.X. [Center for Biomedical Materials and Engineering, Harbin Engineering University, Harbin 150001 (China); Zheng, Y.F., E-mail: yfzheng@pku.edu.cn [Center for Biomedical Materials and Engineering, Harbin Engineering University, Harbin 150001 (China); Li, L. [Center for Biomedical Materials and Engineering, Harbin Engineering University, Harbin 150001 (China)

2017-03-15

Amorphous SiO{sub 2} coatings were prepared on sintered NdFeB magnets by micro-arc oxidation (MAO) in silicate solution. The surface and cross-sectional morphologies, element and phase composition, corrosion resistance and magnetic properties of the coatings were investigated by scanning electron microscopy (SEM), energy dispersive X-ray spectrometer (EDS), X-ray photoelectron spectroscopy (XPS), potentiodynamic polarization test and physical properties measurements system (PPMS). The results showed that the surface morphologies of the coatings exhibited the “coral reef” like structure, different from the typical MAO porous structure. With increasing the voltages, the thickness of the coatings increased from 12.72 to 19.90 µm, the content of Si element increased, while the contents of Fe, Nd and P elements decreased. The coatings were mainly composed of amorphous SiO{sub 2} and a few amorphous Fe{sub 2}O{sub 3} and Nd{sub 2}O{sub 3}. The amorphous SiO{sub 2} coatings presented excellent thermal shock resistance, while the thermal shock resistance decreased with increasing the voltages. The corrosion resistance of the coatings increased with increasing the voltages, and it could be enhanced by one order of magnitude compared to the uncoated NdFeB magnets. The MAO coatings slightly decreased the magnetic properties of the NdFeB samples in different degrees. - Highlights: • Amorphous SiO{sub 2} coatings were prepared on sintered NdFeB magnets by micro-arc oxidation. • The coatings presented excellent thermal shock resistance. • The corrosion resistance could be enhanced by one order of magnitude. • The MAO coatings slightly decreased the magnetic properties of the NdFeB samples.

XPS and TEM study of W-DLC/DLC double-layered film

International Nuclear Information System (INIS)

Takeno, Takanori; Komiyama, Takao; Miki, Hiroyuki; Takagi, Toshiyuki; Aoyama, Takashi

2009-01-01

A double-layered film of tungsten-containing diamond-like carbon (W-DLC) and DLC, (W-DLC)/DLC, was investigated. A film of 1.6 μm in thickness was deposited onto silicon substrate. The investigate double-layered coating was deposited by using the combination of PECVD and co-sputtering of tungsten metal target. Structure, interface and chemical bonding state of the investigated film were analyzed by Transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS). From the results of the analyses, the structure of double-layered film is that amorphous phase of carbon is continued from DLC to W-DLC and tungsten metal clusters are dispersed in W-DLC layer.

Applications in the Nuclear Industry for Thermal Spray Amorphous Metal and Ceramic Coatings

OpenAIRE

Blink, J.; Farmer, J.; Choi, J.; Saw, C.

2009-01-01

Amorphous metal and ceramic thermal spray coatings have been developed with excellent corrosion resistance and neutron absorption. These coatings, with further development, could be cost-effective options to enhance the corrosion resistance of drip shields and waste packages, and limit nuclear criticality in canisters for the transportation, aging, and disposal of spent nuclear fuel. Iron-based amorphous metal formulations with chromium, molybdenum, and tungsten have shown the corrosion resis...

Generation of amorphous ceramic capacitor coatings on titanium using a continuous sol-gel process

International Nuclear Information System (INIS)

Dixon, B.G.; Walsh, M.A. III; Phillips, P.G.; Morris, R.S.

1995-01-01

Thin amorphous films of ceramic capacitor materials were successfully deposited using sol-gel chemistry onto titanium wire using a continuous, computer controlled process. By repeatedly depositing and calcining very thin layers of material, smooth and even coats can be produced. Surface analyses revealed the layered nature of these thin coats, as well as the amorphous nature of the ceramic. The electrical properties of the better coatings, all composed of niobium, bismuth, zinc oxides, were then evaluated. copyright 1995 Materials Research Society

Comet 17P/Holmes: Possibility of a CO driven explosion

Science.gov (United States)

Kossacki, Konrad J.; Szutowicz, Slawomira

2011-04-01

This work is a continuation of our previous paper about brightening of Comet 17P/Holmes (Kossacki, K.J., Szutowicz, S. [2010]. Icarus 207, 320-340). In that paper we presented results of simulations indicating that the nonuniform crystallization of amorphous water ice itself is probably not sufficient for an explosion. In the present work we investigate the possibility that the explosion is caused by a rapid sublimation of the CO ice leading to the rise of gas pressure above the tensile strength of the nucleus. We simulated evolution of a model nucleus in the orbit of Comet 17P/Holmes. The nucleus is composed of water ice, carbon monoxide ice and dust and has the shape of an elongated ellipsoid. The simulations include crystallization of amorphous ice in the nucleus, changes of the dust mantle thickness, and sublimation of the CO ice. In our model CO is mantling grains composed of dust and amorphous water ice. Orientation of the nuclear spin axis in space is the same as derived in Moreno et al. (Moreno, F., Ortiz, J.L., Santos-Sanz, P., Morales, N., Vidal-Nunez, M.J., Lara, L.M., Gutierrez, P.J. [2008]. Astrophys. J. 677, L63-L66) for Comet Holmes during recent brightening event. Hence, the angle between the orbital and the equatorial planes of the comet is I = 95°, and the cometocentric solar longitude at perihelion is Φ = 210°. The calculations are performed for the south pole being the sub-solar point close to time of the outburst. Our computations indicate, that the CO pressure within the comet nucleus can rise to high values. When the layer between the dust mantle and the crystallization front of the amorphous water ice is very fine grained, few microns in radius, the CO pressure within the nucleus can exceed 10 kPa. This value is the lowest estimate for the tensile strength of the nucleus of Comet Holmes (Reach, W.T., Vaubaillon, J., Lisse, C.M., Holloway, M., Rho, J. [2010]. Icarus 208, 276-292). Hence, when the gas pressure reaches this value the nucleus

Effect of Load on Friction-Wear Behavior of HVOF-Sprayed WC-12Co Coatings

Science.gov (United States)

Yifu, Jin; Weicheng, Kong; Tianyuan, Sheng; Ruihong, Zhang; Dejun, Kong

2017-07-01

A WC-12Co coating was sprayed on AISI H13 hot work mold steel using a high-velocity oxygen fuel. The morphologies, phase compositions, and distributions of chemical elements of the obtained coatings were analyzed using a field emission scanning electron microscope, x-ray diffraction, and energy-dispersive spectroscope (EDS), respectively. The friction-wear behaviors under different loads were investigated using a reciprocating wear tester; the morphologies and distributions of the chemical elements of worn tracks were analyzed using a SEM and its configured EDS, respectively. The results show the reunited grains of WC are held together by the Co binder; the primary phases of the coating are WC, Co, and a small amount of W2C and W, owing to the oxidation and decarburization of WC. Inter-diffusion of Fe and W between the coating and the substrate is shown, which indicates a good coating adhesion. The values of the average coefficient of friction under the loads of 40, 80, and 120 N are 0.29, 0.31, and 0.49, respectively. The WC grains are pulled out of the coating during the sliding wear test, but the coating maintains its integrity, suggesting that the coating is intact and continuously protects the substrate from wearing.

Effect of mating materials on wear properties of amorphous hydrogenated carbon (a-C:H coating and tetrahedral amorphous carbon (ta-C coating in base oil boundary lubrication condition

Directory of Open Access Journals (Sweden)

Xiang Li

2017-12-01

Full Text Available In this study, wear behavior of amorphous hydrogenated carbon (a-C:H coating and tetrahedral amorphous carbon (ta-C coating when sliding against various mating materials in base oil boundary lubrication condition is comparatively investigated to find out the optimal combinations of DLC/mating material and corresponding wear mechanism of both DLC coating. Tribological tests were performed in a cylinder-on-disc tribometer, Field Emission Scanning Electron Microscopy, Raman spectroscopy is used for characterization of ta-C and a-C:H worn surface. The results show that the specific wear rate of ta-C coating increases along with the hardness and roughness of mating material increases, while the specific wear rate of a-C:H coating increases together with an increment in the ID/IG ratio. It is concluded that for ta-C coating, local stress concentration-induced microfracture is the main wear mechanism in relative high wear scenario, along with minor graphitization-induced wear which prevails in low wear scenario. On the other hand, a-C:H coating showed that simultaneous generation and removal of the graphitized layer on the contact surface is the predominant wear mechanism.

Study on applicability of highly corrosion-resistant amorphous coating techniques to components of reprocessing plant

International Nuclear Information System (INIS)

Ebata, Makoto; Okuyama, Gen; Chiba, Shigeru; Matsunaga, Tsunebumi

1991-01-01

In view of the growing need for prolongation of lives of reprocessing plant installations, we recently investigated the applicability of highly corrosion-resistant amorphous coating techniques to such plant components as to be subjected to a badly corrosive environment created by high temperatures, boiling nitric acid (HNO 3 ), etc. As the result, giving a preference to the Ta-based amorphous alloys exhibiting high corrosion-resistance in HNO 3 solutions, we made specimens of stainless steel plates coated with the above amorphous alloys through the sputtering process thereof. To our satisfaction, these specimens successfully passed various HNO 3 corrosion tests as described later on. Ta-based amorphous films give cathodic protection to 310 Nb stainless steel plates, and that with extremely low corrosion rates of themselves as protecting agents. For these reasons, we are confident that there will be no practical problems at all, in case we adopt stainless steel plates partially coated with such amorphous alloys for use in a nitric-acid environment. In this paper, we explain the comparative tests for various amorphous alloys with different compositions, referring also to the thus-selected Ta-based amorphous alloy along with several kinds of corrosion tests specially arranged for the same alloy. (author)

Dissolution properties of co-amorphous drug-amino acid formulations in buffer and biorelevant media.

Science.gov (United States)

Heikkinen, A T; DeClerck, L; Löbmann, K; Grohganz, H; Rades, T; Laitinen, R

2015-07-01

Co-amorphous formulations, particularly binary drug-amino acid mixtures, have been shown to provide enhanced dissolution for poorly-soluble drugs and improved physical stability of the amorphous state. However, to date the dissolution properties (mainly intrinsic dissolution rate) of the co-amorphous formulations have been tested only in buffers and their supersaturation ability remain unexplored. Consequently, dissolution studies in simulated intestinal fluids need to be conducted in order to better evaluate the potential of these systems in increasing the oral bioavailability of biopharmaceutics classification system class II drugs. In this study, solubility and dissolution properties of the co-amorphous simvastatin-lysine, gibenclamide-serine, glibenclamide-threonine and glibenclamide-serine-threonine were studied in phosphate buffer pH 7.2 and biorelevant media (fasted and fed state simulated intestinal fluids (FaSSIF and FeSSIF, respectively)). The co-amorphous formulations were found to provide a long-lasting supersaturation and improve the dissolution of the drugs compared to the crystalline and amorphous drugs alone in buffer. Similar improvement, but in lesser extent, was observed in biorelevant media suggesting that a dissolution advantage observed in aqueous buffers may overestimate the advantage in vivo. However, the results show that, in addition to stability advantage shown earlier, co-amorphous drug-amino acid formulations provide dissolution advantage over crystalline drugs in both aqueous and biorelevant conditions.

Laser cladding Co-based alloy/SiCp composite coatings on IF steel

International Nuclear Information System (INIS)

Li Mingxi; He Yizhu; Sun Guoxiong

2004-01-01

Hardfacing coatings, made of Co-Cr-W-Ni-Si alloy + 20% SiCp, deposited by laser cladding on IF steel is introduced. Cross-section of such coatings has been examined to reveal their microstructure using optical microscope, scanning electron microscope (SEM) and X-ray diffractometer (XRD). MM-200 type wear tester is used to examine wear resistance of the coatings. The results showed that SiCp is dissolved completely during laser cladding process under this conditions, the primary phase γ-Co dendrite and Si 2 W, CoWSi, Cr 3 Si, CoSi 2 formed by C, Si reacting with other elements existed in the coatings. There existed some crystallization morphologies in different regions, such as planar (at the interface), followed cellular and dendrite crystallization from interface to the surface. The direction of solidification changes from one direction perpendicular to interface to multi-directions at the central and upper regions of the clad. The results also showed that the wear resistance of the clad improved by adding SiCp

Post-treatment of Plasma-Sprayed Amorphous Ceramic Coatings by Spark Plasma Sintering

Science.gov (United States)

Chraska, T.; Pala, Z.; Mušálek, R.; Medřický, J.; Vilémová, M.

2015-04-01

Alumina-zirconia ceramic material has been plasma sprayed using a water-stabilized plasma torch to produce free standing coatings. The as-sprayed coatings have very low porosity and are mostly amorphous. The amorphous material crystallizes at temperatures above 900 °C. A spark plasma sintering apparatus has been used to heat the as-sprayed samples to temperatures above 900 °C to induce crystallization, while at the same time, a uniaxial pressure of 80 MPa has been applied to their surface. After such post-treatment, the ceramic samples are crystalline and have very low open porosity. The post-treated material exhibits high hardness and significantly increased flexural strength. The post-treated samples have a microstructure that is best described as nanocomposite with the very small crystallites embedded in an amorphous matrix.

Effect of temperature and pH of ammonium galvanic bath on the properties of Zn-Co alloy coatings

Energy Technology Data Exchange (ETDEWEB)

Maciej, A; Michalska, J [Department of Materials Science, Silesian University of Technology, 40-019 Katowice (Poland); Simka, W; Nawrat, G; Piotrowski, J, E-mail: artur.maciej@polsl.pl [Faculty of Chemistry, Silesian University of Technology, 44-100 Gliwice (Poland)

2011-05-15

The results of investigations on Zn-Co coatings obtained electrochemically in acidic and neutral ammonium baths are presented. The chemical composition, morphology and surface roughness of received coatings were determined together with the current efficiency. It was found that the coatings morphology depends on the process parameters. In the case of neutral bath the increase of bath temperature resulted in decrease of cobalt contents in the coatings, whereas it was not practically observed for acidic baths. It was also observed that surface roughness of the Zn-Co coatings decreased with the increase of temperature for both types of baths. It was also found that the grain size of coatings obtained in neutral bath depends on pH of bath.

Surface studies of Os Re W alloy-coated impregnated tungsten cathodes

International Nuclear Information System (INIS)

Ares Fang, C.S.; Maloney, C.E.

1990-01-01

Impregnated tungsten cathodes half-coated with Re/W (or Os/W) alloy and Os Re W alloy at right angles were studied to compare the effects of Os Re W alloy coatings on the electron emission and emission mechanisms. Constant surface metal compositions of 32% Os--29% Re--39% W and 35% Os--26% Re--39% W were obtained from the activated surfaces initially coated with 40% Os--40% Re--20% W and 35% Os--45% Re--20% W alloys, respectively. Thermionic emission microscopy measurements showed that the Os Re W alloy-coated surface gives an average effective work function of 0.29, 0.08, and 0.03 eV lower than the uncoated, Re/W and Os/W alloy-coated surfaces. An effective work function of 1.73 eV was obtained from an activated Os Re W alloy surface. Auger studies exhibited a smaller BaO coverage and a higher barium coverage in excess of BaO stoichiometry on the Os Re W alloy-coated surface compared to the uncoated, Re/W and Os/W alloy-coated surfaces

Enhancement of photovoltaic effects and photoconductivity observed in Co-doped amorphous carbon/silicon heterostructures

Energy Technology Data Exchange (ETDEWEB)

Jiang, Y. C.; Gao, J., E-mail: jugao@hku.hk [Research Center for Solid State Physics and Materials, School of Mathematics and Physics, Suzhou University of Science and Technology, Suzhou 215009, Jiangsu (China)

2016-08-22

Co-doped amorphous carbon (Co-C)/silicon heterostructures were fabricated by growing Co-C films on n-type Si substrates using pulsed laser deposition. A photovoltaic effect (PVE) has been observed at room temperature. Open-circuit voltage V{sub oc} = 320 mV and short-circuit current density J{sub sc }= 5.62 mA/cm{sup 2} were measured under illumination of 532-nm light with the power of 100 mW/cm{sup 2}. In contrast, undoped amorphous carbon/Si heterostructures revealed no significant PVE. Based on the PVE and photoconductivity (PC) investigated at different temperatures, it was found that the energy conversion efficiency increased with increasing the temperature and reached the maximum at room temperature, while the photoconductivity showed a reverse temperature dependence. The observed competition between PVE and PC was correlated with the way to distribute absorbed photons. The possible mechanism, explaining the enhanced PVE and PC in the Co-C/Si heterostructures, might be attributed to light absorption enhanced by localized surface plasmons in Co nanoparticles embedded in the carbon matrix.

Electrodeposition of Nanocrystalline Co-P Coatings as a Hard Chrome Alternative (Briefing Charts)

Science.gov (United States)

2011-02-10

chrome plating utilizes chromium in the hexavalent state (Cr6+) Cr6+ is a known carcinogen and poses a health risk to operators OSHA lowered the Cr6+ PEL...from 52 µg/m3 to 5 µg/m3 8 Apr 09, Memorandum, DoD Directive Hexavalent Chromium Management Policy NAVAIR Cr6+ Authorization Process Hard Chrome ...Aerospace & Defense February 10, 2011 Electrodeposition of Nanocrystalline Co-P Coatings as a Hard Chrome Alternative Jack Benfer Co-PI NAVAIR

Corrosion resistance and cytocompatibility of biodegradable surgical magnesium alloy coated with hydrogenated amorphous silicon.

Science.gov (United States)

Xin, Yunchang; Jiang, Jiang; Huo, Kaifu; Tang, Guoyi; Tian, Xiubo; Chu, Paul K

2009-06-01

The fast degradation rates in the physiological environment constitute the main limitation for the applications of surgical magnesium alloys as biodegradable hard-tissue implants. In this work, a stable and dense hydrogenated amorphous silicon coating (a-Si:H) with desirable bioactivity is deposited on AZ91 magnesium alloy using magnetron sputtering deposition. Raman spectroscopy and Fourier transform infrared spectroscopy reveal that the coating is mainly composed of hydrogenated amorphous silicon. The hardness of the coated alloy is enhanced significantly and the coating is quite hydrophilic as well. Potentiodynamic polarization results show that the corrosion resistance of the coated alloy is enhanced dramatically. In addition, the deterioration process of the coating in simulated body fluids is systematically investigated by open circuit potential evolution and electrochemical impedance spectroscopy. The cytocompatibility of the coated Mg is evaluated for the first time using hFOB1.19 cells and favorable biocompatibility is observed. 2008 Wiley Periodicals, Inc.

Identifying the optimal HVOF spray parameters to attain minimum porosity and maximum hardness in iron based amorphous metallic coatings

Directory of Open Access Journals (Sweden)

S. Vignesh

2017-04-01

Full Text Available Flow based Erosion – corrosion problems are very common in fluid handling equipments such as propellers, impellers, pumps in warships, submarine. Though there are many coating materials available to combat erosion–corrosion damage in the above components, iron based amorphous coatings are considered to be more effective to combat erosion–corrosion problems. High velocity oxy-fuel (HVOF spray process is considered to be a better process to coat the iron based amorphous powders. In this investigation, iron based amorphous metallic coating was developed on 316 stainless steel substrate using HVOF spray technique. Empirical relationships were developed to predict the porosity and micro hardness of iron based amorphous coating incorporating HVOF spray parameters such as oxygen flow rate, fuel flow rate, powder feed rate, carrier gas flow rate, and spray distance. Response surface methodology (RSM was used to identify the optimal HVOF spray parameters to attain coating with minimum porosity and maximum hardness.

Microstructure and property of Fe–Co–B–Si–C–Nb amorphous composite coating fabricated by laser cladding process

International Nuclear Information System (INIS)

Zhu, Y.Y.; Li, Z.G.; Li, R.F.; Li, M.; Daze, X.L.; Feng, K.; Wu, Y.X.

2013-01-01

Laser cladding of Fe 34 Co 34 B 20 Si 5 C 3 Nb 4 on a low carbon steel substrate was conducted using coaxial powder feeding method. Microstructure, phase and microhardness were investigated by scanning electronic microscopy, transmission electron microscopy, X-ray diffraction, electron probe micro-analysis and microhardness tester. Amorphous coating with NbC particles embedded in the matrix was formed. Differential scanning calorimetry curve showed that the glass transition temperature (T g ) and the onset crystallization temperature (T x ) were 799 K and 850 K, respectively. The supercooled liquid region (ΔT x = T x − T g ) was as large as 51 K, which implied the high thermal stability of the supercooled liquid against crystallization. Due to the NbC particles embedded in the amorphous matrix, the mean value of the microhardness of the coating prepared by laser cladding was higher than that of the bulk metallic glass formed by the copper mold casting method. The contribution of NbC particles to the total microhardness was theoretically estimated. The estimated hardness of the composite coating agreed well with the tested value.

Microstructure and interfacial evaluation of Co-based alloy coating on copper by pulsed Nd:YAG multilayer laser cladding

International Nuclear Information System (INIS)

Yan Hua; Wang Aihua; Xu Kaidong; Wang Wenyan; Huang Zaowen

2010-01-01

Laser cladding defect-free coatings on copper is rather difficult. The purpose of this study is to fabricate high quality Co-based alloy coating on copper substrate by laser cladding. Powder preplacement with a thickness of 0.7 mm improves the absorptivity of copper substrate to laser effectively and generates defect-free coating. Microstructures, phase constitutions and wear properties are investigated by means of scanning electronic microscopy (SEM) with X-ray energy dispersive microanalysis (EDX), transmission electron microscopy (TEM) and X-ray diffraction (XRD), as well as dry sliding wear test. Experimental results show that α-Co solution, Cr 23 C 6 , Ni 17 W 3 and Cr 4 Ni 15 W are the main phases in the Co-based coating. The Ni-based solid solutions (α-Co, Ni) and (Ni, Cu) are formed at interface, which generate metallurgical bonding by diffusion between Co-based coating and copper substrate. The average microhardness of the coating is 478HV 0.1 . Wear resistance of copper is significantly improved by laser cladding Co-based alloy multilayer coating.

HIGHWAY INFRASTRUCTURE FOCUS AREA NEXT-GENERATION INFRASTRUCTURE MATERIALS VOLUME I - TECHNICAL PROPOSAL & MANAGEMENTENHANCEMENT OF TRANSPORTATION INFRASTRUCTURE WITH IRON-BASED AMORPHOUS-METAL AND CERAMIC COATINGS

Energy Technology Data Exchange (ETDEWEB)

Farmer, J C

2007-12-04

The infrastructure for transportation in the United States allows for a high level of mobility and freight activity for the current population of 300 million residents, and several million business establishments. According to a Department of Transportation study, more than 230 million motor vehicles, ships, airplanes, and railroads cars were used on 6.4 million kilometers (4 million miles) of highways, railroads, airports, and waterways in 1998. Pipelines and storage tanks were considered to be part of this deteriorating infrastructure. The annual direct cost of corrosion in the infrastructure category was estimated to be approximately $22.6 billion in 1998. There were 583,000 bridges in the United States in 1998. Of this total, 200,000 bridges were steel, 235,000 were conventional reinforced concrete, 108,000 bridges were constructed using pre-stressed concrete, and the balance was made using other materials of construction. Approximately 15 percent of the bridges accounted for at this point in time were structurally deficient, primarily due to corrosion of steel and steel reinforcement. Iron-based amorphous metals, including SAM2X5 (Fe{sub 49.7}Cr{sub 17.7}Mn{sub 1.9}Mo{sub 7.4}W{sub 1.6}B{sub 15.2}C{sub 3.8}Si{sub 2.4}) and SAM1651 (Fe{sub 48}Mo{sub 14}Cr{sub 15}Y{sub 2}C{sub 15}B{sub 6}) have been developed, and have very good corrosion resistance. These materials have been prepared as a melt-spun ribbons, as well as gas atomized powders and thermal-spray coatings. During electrochemical testing in several environments, including seawater at 90 C, the passive film stabilities of these materials were found to be comparable to that of more expensive high-performance alloys, based on electrochemical measurements of the passive film breakdown potential and general corrosion rates. These materials also performed very well in standard salt fog tests. Chromium (Cr), molybdenum (Mo) and tungsten (W) provided corrosion resistance, and boron (B) enabled glass formation

Fabrication of amorphous Si and C anode films via co-sputtering for an all-solid-state battery

Energy Technology Data Exchange (ETDEWEB)

Lee, K.S. [Department of Materials Science and Engineering, Yonsei University Shinchondong, 262 Seongsanno, Seodaemoongu, Seoul 120-749 (Korea, Republic of); Department of Environment and Energy Engineering, Gachon University, Seongnamdaero 1342, 461-710 Gyeonggi-do (Korea, Republic of); Lee, S.H. [Department of Environment and Energy Engineering, Gachon University, Seongnamdaero 1342, 461-710 Gyeonggi-do (Korea, Republic of); Woo, S.P. [Department of Materials Science and Engineering, Yonsei University Shinchondong, 262 Seongsanno, Seodaemoongu, Seoul 120-749 (Korea, Republic of); Department of Environment and Energy Engineering, Gachon University, Seongnamdaero 1342, 461-710 Gyeonggi-do (Korea, Republic of); Kim, H.S. [Department of Mechanical Engineering, Gachon University, Seongnamdaero 1342, 461-710 Gyeonggi-do (Korea, Republic of); Yoon, Y.S., E-mail: benedicto@gachon.ac.kr [Department of Environment and Energy Engineering, Gachon University, Seongnamdaero 1342, 461-710 Gyeonggi-do (Korea, Republic of)

2014-08-01

In this study, a combination of silicon and carbon as the anode material for an all-solid-state battery has been investigated to overcome their individual deficiencies. The capacity of silicon thin films with an input power of 60 W shows dramatic failure after 38 cycles due to serious volume expansion. In contrast, C thin films at 60 W show high stability of cyclic performance and capacity retention. The amorphous silicon and carbon composite reduced the volume expansion of silicon during long term cycles and enhanced the low specific capacity of the carbon. This resistance of the volume expansion might be expected from the cushion effect caused by the carbon, which was confirmed by scanning electron microscope images after a 100 cycle test. These results indicate that amorphous silicon and carbon composite thin films have a high possibility as the stable anode material for an all-solid-state battery. - Highlights: • Amorphous Si/C nanocomposite thin films have been prepared by co-sputtering. • Carbon can act as a cushion effect to prevent volume expansion of Si. • Amorphous Si/C nanocomposite thin films show structure stability at 100 cycles. • Capacity of the amorphous Si/C nanocomposite thin films was enhanced considerably.

Improvement of the physicochemical properties of Co-amorphous naproxen-indomethacin by naproxen-sodium

DEFF Research Database (Denmark)

Beyer, Andreas; Grohganz, Holger; Löbmann, Korbinian

2017-01-01

Improvement of the physicochemical properties of amorphous active pharmaceutical ingredients (APIs) applying the concept of co-amorphisation is a promising alternative to the use of polymer glass solutions. In co-amorphous systems, the physical stability and the dissolution rate of the involved c...... or full exchange of naproxen by its sodium salt was performed, which may present a general optimization method to improve co-amorphous systems....... In the present study, it was thus tested if the physicochemical properties of co-amorphous naproxen-indomethacin could be optimized by incorporation of the naproxen sodium into the system. Three different co-amorphous systems in nine different molar ratios were prepared by quench-cooling: naproxen...... components may be improved in comparison to the respective single amorphous phases. However, for the co-amorphous naproxen-indomethacin model system it has been reported that recrystallization could not be prevented for more than 112days regardless of the applied preparation method and blend ratio...

Minor-Cu doped soft magnetic Fe-based FeCoBCSiCu amorphous alloys with high saturation magnetization

Science.gov (United States)

Li, Yanhui; Wang, Zhenmin; Zhang, Wei

2018-05-01

The effects of Cu alloying on the amorphous-forming ability (AFA) and magnetic properties of the P-free Fe81Co5B11C2Si1 amorphous alloy were investigated. Addition of ≤ 1.0 at.% Cu enhances the AFA of the base alloy without significant deterioration of the soft magnetic properties. The Fe80.5Co5B11C2Si1Cu0.5 alloy with the largest critical thickness for amorphous formation of ˜35 μm possesses a high saturation magnetization (Bs) of ˜1.78 T, low coercivity of ˜14.6 A/m, and good bending ductility upon annealing in a wide temperature range of 513-553 K with maintaining the amorphous state. The fabrication of the new high-Fe-content Fe-Co-B-C-Si-Cu amorphous alloys by minor doping of Cu gives a guideline to developing high Bs amorphous alloys with excellent AFA.

The chemistry and structure of nickel–tungsten coatings obtained by pulse galvanostatic electrodeposition

International Nuclear Information System (INIS)

Argañaraz, M.P. Quiroga; Ribotta, S.B.; Folquer, M.E.; Zelaya, E.; Llorente, C.; Ramallo-López, J.M.; Benítez, G.; Rubert, A.; Gassa, L.M.; Vela, M.E.; Salvarezza, R.C.

2012-01-01

A detailed characterization of electrodeposited Ni-W coatings prepared by pulse electrodeposition on steel and copper substrates is presented. The coatings were obtained at high current pulse frequency and show high microhardness and absence of brittleness. The surface of the coating consists of nanometer sized crystals forming a cauliflower-like structure protected by a mixture of nickel and tungsten oxides. The cauliflower structure is preserved into the bulk coating that exhibits an average composition ≈70 at% Ni-30 at% W. Different phases are observed in the bulk structure: a W-rich amorphous phase (≈40%) and Ni-rich crystalline phases (≈60%). The crystalline phases consist of crystalline domains ≈7 nm in size of Ni(W) (fcc) solid solution (12 at% W content) and a minor Ni 4 W component (less than 10%). The amorphous phase exhibits a less compact Ni-W structure where some amount of C could also be present. Oxidized W species cannot be detected in the bulk coating, thus discarding the presence of significant amounts of tungsten carbide, tungstates or citrate–tungsten complexes. Our results shed light on controversial points related to the chemical composition and demonstrate the complex structure of this system.

WC-Co coatings deposited by the electro-thermal chemical spray method

Energy Technology Data Exchange (ETDEWEB)

Zhitomirsky, V.N. [Tel Aviv Univ. (Israel). Faculty of Engineering; Wald, S.; Rabani, L.; Zoler, D. [Propulsion Physics Division, SOREQ NRC, 81800, Yavne (Israel); Factor, M.; Roman, I. [School of Applied Sciences, The Hebrew University, 91904, Jerusalem (Israel); Cuperman, S.; Bruma, C. [School of Physics and Astronomy, Tel-Aviv University, 69978, Tel-Aviv (Israel)

2000-10-02

A novel thermal spray technology - an electro-thermal chemical spray (ETCS) for producing hard coatings is presented. The experimental coating apparatus consists of a machine gun barrel, a cartridge containing the coating material in powder form, a solid propellant, and a plasma ignition system. The plasma ignition system produces plasma in pulsed mode to ignite the solid propellant. On ignition, the drag force exerted by the combustion gases accelerates the powder particles towards the substrate. Using the ETCS technique, the process of single-shot WC-Co coating deposition on stainless steel substrate was studied. The influence of process parameters (plasma energy, mass of the solid propellant and the coated powder, distance between the gun muzzle and the substrate) on the coating structure and some of its properties were investigated. It was shown that ECTS technique effectively deposited the WC-Co coating with deposition thicknesses of 100-200 {mu}m per shot, while deposition yield of {proportional_to}70% was attained. The WC-Co coatings consisted of carbide particles distributed in amorphous matrix. The powder particle velocity was found to depend on the solid propellant mass and was weakly dependent on the plasma energy, while the particle processing temperature was strongly dependent on the plasma energy and almost independent of the solid propellant mass. Whilst increasing the solid propellant mass from 5 to 7 g, the deposition rate and yield correspondingly increased. When increasing the plasma energy, the temperature of the powder particles increased, the average carbide particle size decreased and their shape became more rounded. The deposition yield and microhardness at first increased and then achieved saturation by increasing the plasma energy. (orig.)

Effects of post annealing on the microstructure, mechanical properties and cavitation erosion behavior of arc-sprayed FeNiCrBSiNbW coatings

International Nuclear Information System (INIS)

Lin, Jinran; Wang, Zehua; Lin, Pinghua; Cheng, Jiangbo; Zhang, Xin; Hong, Sheng

2015-01-01

Highlights: • FeNiCrBSiNbW coatings were prepared by arc spraying process. • Microstructural changes of the coatings were investigated by TEM. • As-sprayed coating had higher cavitation erosion resistance than annealed coatings. • The mechanism for annealing-induced change in cavitation erosion was discussed. - Abstract: FeNiCrBSiNbW coatings were fabricated via arc spraying process and were subsequently annealed at 450, 550 and 650 °C for 1 h to study the effect of annealing treatment on the microstructure, mechanical properties and cavitation erosion behavior. Microstructure was studied using scanning and transmission electron microscopy. The results showed that oxides, fine crystalline particles and borides were formed after annealing at 650 °C. With increasing annealing temperature, the coatings showed reductions in porosity and fracture toughness, and an increase in microhardness. The cavitation erosion behavior of the coatings was investigated in distilled water. The results showed that the cavitation erosion resistance of the coatings decreased with increasing annealing temperature, and the as-sprayed coating exhibited the best cavitation erosion resistance among the four kinds of coatings. This was attributed to the good fracture toughness, high amorphous phase content and the absence of oxides in the as-sprayed coating

Characterization of Amorphous and Co-Amorphous Simvastatin Formulations Prepared by Spray Drying

DEFF Research Database (Denmark)

Craye, Goedele; Löbmann, Korbinian; Grohganz, Holger

2015-01-01

In this study, spray drying from aqueous solutions, using the surface-active agent sodium lauryl sulfate (SLS) as a solubilizer, was explored as a production method for co-amorphous simvastatin-lysine (SVS-LYS) at 1:1 molar mixtures, which previously have been observed to form a co...

Isothermal and dynamic oxidation behaviour of Mo-W doped carbon-based coating

Science.gov (United States)

Mandal, Paranjayee; Ehiasarian, Arutiun P.; Hovsepian, Papken Eh.

2015-10-01

The oxidation behaviour of Mo-W doped carbon-based coating (Mo-W-C) is investigated in elevated temperature (400-1000 °C). Strong metallurgical bond between Mo-W-C coating and substrate prevents any sort of delamination during heat-treatment. Isothermal oxidation tests show initial growth of metal oxides at 500 °C, however graphitic nature of the as-deposited coating is preserved. The oxidation progresses with further rise in temperature and the substrate is eventually exposed at 700 °C. The performance of Mo-W-C coating is compared with a state-of-the-art DLC(Cr/Cr-WC/W:C-H/a:C-H) coating, which shows preliminary oxidation at 400 °C and local delamination of the coating at 500 °C leading to substrate exposure. The graphitisation starts at 400 °C and the diamond-like structure is completely converted into the graphite-like structure at 500 °C. Dynamic oxidation behaviour of both the coatings is investigated using Thermo-gravimetric analysis carried out with a slow heating rate of 1 °C/min from ambient temperature to 1000 °C. Mo-W-C coating resists oxidation up to ˜800 °C whereas delamination of DLC(Cr/Cr-WC/W:C-H/a:C-H) coating is observed beyond ˜380 °C. In summary, Mo-W-C coating provides improved oxidation resistance at elevated temperature compared to DLC(Cr/Cr-WC/W:C-H/a:C-H) coating.

Magnetic leverage effects in amorphous SmCo/CoAlZr heterostructures

International Nuclear Information System (INIS)

Procter, R. A.; Hase, T. P. A.; Magnus, F.; Andersson, G.; Hjörvarsson, B.; Sánchez-Hanke, C.

2015-01-01

Although magnetic heterostructures are the basis of many magnetic technologies, the mechanisms involved in magnetization reversals in such structures are not fully understood, especially in amorphous multilayers. Here, we report on the SmCo/CoAlZr system and exploit resonant magnetic x-ray scattering to probe the element specific magnetization reversals. When combined into a tri-layer structure, two different switching fields and reversal mechanisms are observed for the Sm and Co sub-lattices. We argue that the decoupling of the sub-lattices arises from the local distribution of atomic species within the amorphous matrix leading to a strong magnetic leverage effect and exchange pinning. The decoupling arises due to strong interactions between regions of high Co density which span the interface. The relatively sparse interactions between Sm and Co induce a localized pinning of the Co-rich areas, resulting in an exchange bias in minor loops and an enhanced coercivity

Magnetic leverage effects in amorphous SmCo/CoAlZr heterostructures

Energy Technology Data Exchange (ETDEWEB)

Procter, R. A., E-mail: r.a.procter@warwick.ac.uk; Hase, T. P. A. [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom); Magnus, F.; Andersson, G.; Hjörvarsson, B. [Department of Physics and Astronomy, Uppsala University, Box 516, 751 20 Uppsala (Sweden); Sánchez-Hanke, C. [National Synchrotron Light Source, Brookhaven National Laboratory, Upton, New York 11973 (United States)

2015-08-10

Although magnetic heterostructures are the basis of many magnetic technologies, the mechanisms involved in magnetization reversals in such structures are not fully understood, especially in amorphous multilayers. Here, we report on the SmCo/CoAlZr system and exploit resonant magnetic x-ray scattering to probe the element specific magnetization reversals. When combined into a tri-layer structure, two different switching fields and reversal mechanisms are observed for the Sm and Co sub-lattices. We argue that the decoupling of the sub-lattices arises from the local distribution of atomic species within the amorphous matrix leading to a strong magnetic leverage effect and exchange pinning. The decoupling arises due to strong interactions between regions of high Co density which span the interface. The relatively sparse interactions between Sm and Co induce a localized pinning of the Co-rich areas, resulting in an exchange bias in minor loops and an enhanced coercivity.

Influence of variation in molar ratio on co-amorphous drug-amino acid systems

DEFF Research Database (Denmark)

Jensen, Katrine Birgitte Tarp; Larsen, Flemming Hofmann; Löbmann, Korbinian

2016-01-01

Molecular interactions were investigated within four different co-amorphous drug-amino acid systems, namely indomethacin-tryptophan (Ind-Trp), furosemide-tryptophan (Fur-Trp), indomethacin-arginine (Ind-Arg) and furosemide-arginine (Fur-Arg). The co-amorphous systems were prepared by ball milling...... observed in the 50mol% drug (1:1M ratio) mixtures, with the exception of co-amorphous Ind-Arg where the interactions within the 40mol% drug samples appear equally strong. A particularly large deviation between the theoretical and actual Tgs was observed within co-amorphous Ind-Arg and Fur-Arg systems......-amorphous mixture without additional interactions. The modified equation described the Tgs of the co-amorphous Ind-Arg with excess Arg less well indicating possible further interactions; however, the FTIR and ssNMR data did not support the presence of additional intermolecular drug-amino acid interactions....

Preparation and recrystallization behavior of spray-dried co-amorphous naproxen-indomethacin

DEFF Research Database (Denmark)

Beyer, Andreas; Radi, Lydia; Grohganz, Holger

2016-01-01

(2) factorial design and the obtained samples were analyzed with X-ray powder diffractometry and Fourier-transformed infrared spectroscopy. Evaluation of the data revealed that the preparation of fully amorphous samples could be achieved depending on the process conditions. The resulting recrystallization......To improve the dissolution properties and the physical stability of amorphous active pharmaceutical ingredients, small molecule stabilizing agents may be added to prepare co-amorphous systems. The objective of the study was to investigate if spray-drying allows the preparation of co-amorphous drug...

The properties of electrodeposited Zn-Co coatings

Science.gov (United States)

Mahieu, J.; de Wit, K.; de Cooman, B. C.; de Boeck, A.

1999-10-01

The possibility of increasing the corrosion resistance of automotive sheet steel by electrodepositing with Zn-Co alloy coatings was investigated. Process variables during electrodeposition such as current density, electrolyte flow rate, and pH were varied in order to examine their influence on the electroplating process. Cobalt contents varying from 0.2 to 7 wt% were easily obtained. The influence of these process parameters on the characteristics of the coating could be related to the hydroxide suppression mechanism for anomalous codeposition. The structure and the morphology of the coatings were determined using SEM and XRD analysis. Application properties important for coating systems used in the automotive industry, such as friction behavior, adhesion, and corrosion behavior, were investigated on coatings with varying cobalt content. The corrosion resistance of the Zn-Co alloy layers was found to be better than that of pure zinc coatings.

Reduction of core loss in non-oriented (NO) electrical steel by electroless-plated magnetic coating

International Nuclear Information System (INIS)

Chivavibul, Pornthep; Enoki, Manabu; Konda, Shigeru; Inada, Yasushi; Tomizawa, Tamotsu; Toda, Akira

2011-01-01

An important issue in development of electrical steels for core-laminated products is to reduce core loss to improve energy conversion efficiency. This is usually obtained by tailoring the composition, microstructure, and texture of electrical steels themselves. A new technique to reduce core loss in electrical steel has been investigated. This technique involves electroless plating of magnetic thin coating onto the surface of electrical steel. The material system was electroless Ni-Co-P coatings with different thicknesses (1, 5, and 10 μm) deposited onto the surface of commercially available Fe-3% Si electrical steel. Characterization of deposited Ni-Co-P coating was carried out using X-ray diffraction (XRD), scanning electron microscope (SEM), and energy dispersive X-ray (EDX) spectrometer. The deposited Ni-Co-P coatings were amorphous and composed of 56-59% Ni, 32-35% Co, and 8-10% P by mass. The effect of coatings on core loss of the electrical steel was determined using single sheet test. A core loss reduction of 4% maximum was achieved with the Ni-Co-P coating of 1 μm thickness at 400 Hz and 0.3 T. - Research Highlights: → New approach to reduce core loss of electrical steel by magnetic coating. → Ni-Co-P coating influences core loss of NO electrical steel. → Core loss increases in RD direction but reduces in TD direction.

MC3T3-E1 cell response of amorphous phase/TiO{sub 2} nanocrystal composite coating prepared by microarc oxidation on titanium

Energy Technology Data Exchange (ETDEWEB)

Zhou, Rui [Department of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Wei, Daqing, E-mail: daqingwei@hit.edu.cn [Department of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Yang, Haoyue; Feng, Wei [Department of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Cheng, Su [Department of Mechanical Engineering, School of Architecture and Civil Engineering, Harbin University of Science and Technology, Harbin 150001 (China); Li, Baoqiang; Wang, Yaming; Jia, Dechang; Zhou, Yu [Department of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China)

2014-06-01

Bioactive amorphous phase/TiO{sub 2} nanocrystal (APTN) composite coatings were fabricated by microarc oxidation (MAO) on Ti. The APTN coatings are composed of much amorphous phase with Si, Na, Ca, Ti and O elements and a few TiO{sub 2} nanocrystals. With increasing applied voltage, the micropore density of the APTN coating decreases and the micropore size of the APTN coating increases. The results indicate that less MC3T3-E1 cells attach on the APTN coatings as compared to Ti. However, the APTN coatings greatly enhance the cell proliferation ability and the activity of alkaline phosphatase. The amorphous phase and the concentrations of the released Ca and Si from the APTN coatings during cell culture have significant effects on the cell response. - Highlights: • Amorphous phase/TiO2 nanocrystal (APTN) composite coatings were fabricated. • The MC3T3-E1 cell response of the APTN coatings was evaluated. • The APTN coatings greatly enhanced the cell proliferation ability.

Synthesis of BaTiO3 nanoparticles from TiO2-coated BaCO3 particles derived using a wet-chemical method

Directory of Open Access Journals (Sweden)

Yuuki Mochizuki

2014-03-01

Full Text Available BaCO3 particles coated with amorphous TiO2 precursor are prepared by a wet chemical method to produce BaTiO3 nanoparticles at low temperatures. Subsequently, we investigate the formation behavior of BaTiO3 particles and the particle growth behavior when the precursor is subjected to heat treatment. The state of the amorphous TiO2 coating on the surface of BaCO3 particles depends on the concentration of NH4HCO3, and the optimum concentration is found to be in the range 0.5–1.0 M. Thermogravimetric curves of the BaCO3 particles coated with the TiO2 precursor, prepared from BaCO3 particles of various sizes, show BaTiO3 formation occurring mainly at 550–650 °C in the case of fine BaCO3 particles. However, as evidenced from the curves, the temperature of formation of BaTiO3 shifts to higher values with an increase in the size of the BaCO3 particles. The average particle size of single phase BaTiO3 at heat-treatment temperature of 650–900 °C is observed to be in the range 60–250 nm.

Recent Experimental Results on Amorphous Carbon Coatings for Electron Cloud Mitigation

CERN Document Server

Yin Vallgren, C; Chiggiato, P; Costa Pinto, P; Neupert, H; Taborelli, M; Rumolo, G; Shaposhnikova, E; Vollenberg, W

2011-01-01

Amorphous carbon (a-C) thin films, produced in different coating configurations by using DC magnetron sputtering, have been investigated in laboratory for low secondary electron yield (SEY) applications. After the coatings had shown a reliable low initial SEY, the a-C thin films have been applied in the CERN Super Proton Synchrotron (SPS) and tested with Large Hadron Collider (LHC) type beams.Currently, we have used a-C thin film coated in so-called liner configuration for the electron cloud monitors. In addition the vacuum chambers of three dipole magnets have been coated and inserted into the machine. After describing the different configurations used for the coatings, results of the tests in the machine and a summary of the analyses after extraction will be presented. Based on comparison between different coating configurations, a new series of coatings has been applied on three further dipole magnet vacuum chambers. They have been installed and will be tested in coming machine development runs.

Influence of Solvent Composition on the Performance of Spray-Dried Co-Amorphous Formulations

Directory of Open Access Journals (Sweden)

Jaya Mishra

2018-04-01

Full Text Available Ball-milling is usually used to prepare co-amorphous drug–amino acid (AA mixtures. In this study, co-amorphous drug–AA mixtures were produced using spray-drying, a scalable industrially preferred preparation method. The influence of the solvent type and solvent composition was investigated. Mixtures of indomethacin (IND and each of the three AAs arginine, histidine, and lysine were ball-milled and spray-dried at a 1:1 molar ratio, respectively. Spray-drying was performed at different solvent ratios in (a ethanol and water mixtures and (b acetone and water mixtures. Different ratios of these solvents were chosen to study the effect of solvent mixtures on co-amorphous formulation. Residual crystallinity, thermal properties, salt/partial salt formation, and powder dissolution profiles of the IND–AA mixtures were investigated and compared to pure crystalline and amorphous IND. It was found that using spray-drying as a preparation method, all IND–AA mixtures could be successfully converted into the respective co-amorphous forms, irrespective of the type of solvent used, but depending on the solvent mixture ratios. Both ball-milled and spray-dried co-amorphous samples showed an enhanced dissolution rate and maintained supersaturation compared to the crystalline and amorphous IND itself. The spray-dried samples resulting in co-amorphous samples were stable for at least seven months of storage.

Influence of W content on tribological performance of W-doped diamond-like carbon coatings under dry friction and polyalpha olefin lubrication conditions

International Nuclear Information System (INIS)

Fu, Zhi-qiang; Wang, Cheng-biao; Zhang, Wei; Wang, Wei; Yue, Wen; Yu, Xiang; Peng, Zhi-jian; Lin, Song-sheng; Dai, Ming-jiang

2013-01-01

Highlights: • W-doped DLC coating with various W contents was fabricated. • Friction and wear of DLC coated sample was studied. • The lubricant additive was T307. • The influence of W content on friction under lubrication was unveiled. • The influence of W content on wear under lubrication was studied. - Abstract: The influence on tungsten content on the structure, mechanical properties and tribological performance of W-doped diamond-like carbon (DLC) coatings was studied by X-ray photoelectron spectroscopy, nano-indentation, scratch test, and ball-on-disk friction test. It was found that with increasing W content, the content of WC and free W in the coatings is increased while the content of sp 3 -C in the coatings is decreased. The effect of W content on the hardness and elastic modulus of the coatings is indistinctive, but there exists the highest critical load of scratch test of above 100 N when W content is 3.08 at.%. With the increase of W content, the friction coefficients of W-doped DLC coatings under dry friction conditions are increased while the friction coefficients of W-doped DLC coatings under polyalpha olefin (PAO) lubrication are decreased. With the increase of W content, the wear rates of the DLC-coated samples under dry friction conditions show a minimum value; under pure PAO lubrication, the influence of W content on the wear rates of the DLC-coated samples is indistinctive when the W content is below 10.73 at.% while the wear rates are increased with increasing W content from 10.73 at.% to 24.09 at.%; when lubricated by PAO + thiophosphoric acid amine (T307) salt, the samples coated with the undoped DLC or the W-doped DLC with high W content exhibit low wear rates

Composite Ni-Co-fly ash coatings on 5083 aluminium alloy

Energy Technology Data Exchange (ETDEWEB)

Panagopoulos, C.N., E-mail: chpanag@metal.ntua.gr [Laboratory of Physical Metallurgy, National Technical University of Athens, Zografos, 15780 Athens (Greece); Georgiou, E.P.; Tsopani, A.; Piperi, L. [Laboratory of Physical Metallurgy, National Technical University of Athens, Zografos, 15780 Athens (Greece)

2011-03-15

Ni-Co-fly ash coatings were deposited on zincate treated 5083 wrought aluminium alloy substrates with the aid of the electrodeposition technique. Structural and chemical characterization of the produced composite coatings was performed with the aid of X-ray diffraction (XRD), scanning electron microscopy (SEM) and electron dispersive X-ray analysis (EDS) techniques. The Ni-Co-fly ash coatings were found to consist of a crystalline Ni-Co solid solution with dispersed fly ash particles. In addition, chemical analysis of the Ni-Co matrix showed that it consisted of 80 wt.% Ni and 20 wt.% Co. The co-deposition of fly ash particles leads to a significant increase of the microhardness of the coating. The corrosion behaviour of the Ni-Co-fly ash/zincate coated aluminium alloy, in a 0.3 M NaCl solution (pH = 3.5), was studied by means of potentiodynamic corrosion experiments.

Surface magnetic anisotropy in glass-coated amorphous microwires as determined from ferromagnetic resonance measurements

International Nuclear Information System (INIS)

Garcia-Miquel, H.; Garcia, J.M.; Garcia-Beneytez, J.M.; Vazquez, M.

2001-01-01

The ferromagnetic resonance frequency of different Co base glass-coated amorphous magnetic microwires about 3.5 μm in diameter with negative, vanishing and positive magnetostriction has been investigated from power absorption measurements in the microwave frequency range. The experimental technique employed here involves the replacement of the dielectric of a coaxial transmission line by the sample to be measured. From the evolution of the resonance frequency with DC applied magnetic field, the surface magnetic anisotropy field of the microwires has been quantitatively obtained and, as expected, found to depend on the sign and strength of the magnetostriction. Similar values for the surface anisotropy are obtained in comparison with bulk anisotropy as determined from quasi-static hysteresis loops measurements

Thermo-mechanical properties of W/Mo markers coatings deposited on bulk W

International Nuclear Information System (INIS)

Grigore, E; Ruset, C; Gherendi, M; Chioibasu, D; Hakola, A

2016-01-01

In the present paper marker structures consisting of W/Mo layers were deposited on bulk W samples by using a modified CMSII method. This technology, compared to standard CMSII, prevents the formation of nano-pore structures at interfaces. The thicknesses of the markers were in the range 20–35 μm to balance the requirements associated with the wall erosion in ITER and thermo-mechanical performances. The coatings structure and composition were evaluated by glow discharge optical emission spectrometry (GDOES), and energy dispersive x-ray spectroscopy measurements (EDX). The adhesion of the coatings to the substrate has been assessed by scratch test method. In order to evaluate their effectiveness as potential markers for fusion applications, the marker coatings have been tested in an electron beam facility at a temperature of 1000 °C and a power density of about 3 MW m −2 . A number of 300 pulses with duration of 420 s (35 testing hours) were applied on the marker coated samples. (paper)

Thermo-mechanical properties of W/Mo markers coatings deposited on bulk W

Science.gov (United States)

Grigore, E.; Ruset, C.; Gherendi, M.; Chioibasu, D.; Hakola, A.; contributors, JET

2016-02-01

In the present paper marker structures consisting of W/Mo layers were deposited on bulk W samples by using a modified CMSII method. This technology, compared to standard CMSII, prevents the formation of nano-pore structures at interfaces. The thicknesses of the markers were in the range 20-35 μm to balance the requirements associated with the wall erosion in ITER and thermo-mechanical performances. The coatings structure and composition were evaluated by glow discharge optical emission spectrometry (GDOES), and energy dispersive x-ray spectroscopy measurements (EDX). The adhesion of the coatings to the substrate has been assessed by scratch test method. In order to evaluate their effectiveness as potential markers for fusion applications, the marker coatings have been tested in an electron beam facility at a temperature of 1000 °C and a power density of about 3 MW m-2. A number of 300 pulses with duration of 420 s (35 testing hours) were applied on the marker coated samples.

Magnetic anisotropy in rapidly quenched amorphous glass-coated nanowires

Energy Technology Data Exchange (ETDEWEB)

Óvári, T.-A.; Rotărescu, C.; Atițoaie, A.; Corodeanu, S.; Lupu, N., E-mail: nicole@phys-iasi.ro; Chiriac, H.

2016-07-15

Results on the roles played by the magnetoelastic and magnetostatic anisotropy terms in the magnetic behavior of glass-coated magnetostrictive amorphous nanowires prepared by means of rapid solidification are reported. Their contributions have been analyzed both experimentally, through hysteresis loop measurements, and theoretically, using micromagnetic simulations. All the investigated samples exhibit a magnetically bistable behavior, characterized by a single-step magnetization reversal when the applied field reaches a critical threshold value, called switching field. The combined interpretation of the experimental and theoretical data allows one to understand the effect of the magnetoelastic term on the value of the switching field, on one hand, and the effect of the magnetostatic term on the nucleation mechanism on the other, both with an essential impact on the characteristics of the nanowires’ magnetic bistability. The results are crucial for understanding the basic magnetic properties of these novel rapidly solidified ultrathin magnetic wires, as well as for tailoring their properties according to the specific requirements of various sensing applications. - Highlights: • Glass-coated nanowires have been very recently prepared by rapid solidification. • Amorphous wires change their properties as their diameter reaches the nano range. • Here we report on their main anisotropy terms: magnetoelastic and shape. • The results are essential for tailoring their properties for future applications.

Low temperature thermal conductivity of amorphous (Fe, Ni, Co) (P, B, Si) alloys and their change by heat treatment

International Nuclear Information System (INIS)

Pompe, G.; Gaafar, M.; Buettner, P.; Francke, T.

1983-01-01

The thermal conductivity of amorphous metallic alloys (Fe, Ni, Co)/sub 1-x/ (B, P, Si)/sub x/ is measured in the temperature range 2 to 100 K in the as-produced and heat-treated states. By taking into account the results of Matey and Anderson the influence of the nature of the metalloid and the number of metallic components can be discussed. The change of the thermal conductivity due to a structural relaxation caused by a heat treatment is very different. In the whole range of temperature a rise of the phonon thermal conductivity of the Fe-Co-B alloy is obtained, whereas no change is observed for the Fe-B alloy. At low temperature ( 80 B 20 is investigated. (author)

Influence of electroless coatings of Cu, Ni-P and Co-P on MmNi3.25Al0.35Mn0.25Co0.66 alloy used as anodes in Ni-MH batteries

International Nuclear Information System (INIS)

Raju, M.; Ananth, M.V.; Vijayaraghavan, L.

2009-01-01

Electroless coatings of Ni-P, Co-P and Cu were applied on the surface of non-stoichiometric MmNi 3.25 Al 0.35 Mn 0.25 Co 0.66 (Mm: misch metal) metal hydride alloy. Elemental analysis was made with Energy Dispersive X-ray Analysis (EDAX). The structural analysis of bare and coated alloys was done by X-ray diffraction (XRD) whereas surface morphology was examined with scanning electron microscope (SEM) and transmission electron microscope (TEM). The electrode characteristics inclusive of electrochemical capacity and cycle life were studied at C/5 rate. Superior performance is obtained with copper coated alloy. Microstructure observations indicate that the observed excellent performance could be attributed to uniform and efficient surface coverage with copper. Also, lanthanum surface enrichment in samples during Cu coating leads to improvement in performance. It is inferred from electro analytical investigations that copper coatings act as microcurrent collectors with alterations in hydrogen transport mechanism and facilitate charge transfer reaction on the alloy surface without altering battery properties. Moreover, supportive first time TEM evidence of existence of such copper nano current collectors (about 8 nm in diameter and length about 20 nm) is reported.

Clozapine-carboxylic acid plasticized co-amorphous dispersions: Preparation, characterization and solution stability evaluation

Directory of Open Access Journals (Sweden)

Ali Ahmed Mahmoud Abdelhaleem

2015-06-01

Full Text Available This study addressed the possibility of forming of co-amorphous systems between clozapine (CZ and various carboxylic acid plasticizers (CAPs. The aim was to improve the solubility and oral bioavailability of clozapine. Co-amorphous dispersions were prepared using modified solvent evaporation methodology at drug/plasticizer stoichiometric ratios of 1:1, 1:1.5 and 1:2. Solid state characterization was performed using differential scanning calorimetry, X-ray diffraction and infra red spectroscopy. Highly soluble homogeneous co-amorphous dispersions were formed between clozapine and CAPs via hydrogen bonding. The co-amorphous dispersions formed with tartaric acid (1:2 showed the highest dissolution percentage (> 95 % in 20 minutes compared to pure crystalline CZ (56 %. Highly stable solutions were obtained from co-amorphous CZ-citric and CZ-tartaric acid at 1:1.5 molar ratio. The prepared dispersions suggest the possibility of peroral or sublingual administration of highly soluble clozapine at a reduced dose with the great chance to bypass the first pass metabolism.

Amino acids as co-amorphous excipients for simvastatin and glibenclamide

DEFF Research Database (Denmark)

Laitinen, Riikka; Löbmann, Korbinian; Grohganz, Holger

2014-01-01

to a few drugs and amino acids. To facilitate the rational selection of amino acids, the practical importance of the amino acid coming from the biological target site of the drug (and associated intermolecular interactions) needs to be established. In the present study, the formation of co......-amorphous systems using cryomilling and combinations of two poorly water-soluble drugs (simvastatin and glibenclamide) with the amino acids aspartic acid, lysine, serine, and threonine was investigated. Solid-state characterization with X-ray powder diffraction, differential scanning calorimetry, and Fourier...... in the mixtures. Interestingly, a favorable effect by the excipients on the tautomerism of amorphous glibenclamide in the co-amorphous blends was seen, as the formation of the thermodynamically less stable imidic acid tautomer of glibenclamide was suppressed compared to that of the pure amorphous drug...

Composite coating containing WC/12Co cermet and Fe-based metallic glass deposited by high-velocity oxygen fuel spraying

International Nuclear Information System (INIS)

Terajima, Takeshi; Takeuchi, Fumiya; Nakata, Kazuhiro; Adachi, Shinichiro; Nakashima, Koji; Igarashi, Takanori

2010-01-01

A composite coating containing WC/12Co cermet and Fe 43 Cr 16 Mo 16 C 15 B 10 metallic glass was successfully deposited onto type 304 stainless steel by high-velocity oxygen fuel (HVOF) spraying, and the microstructure and tribological properties were investigated. The microstructure of the coating was characterized by scanning electron microscopy/electron probe micro-analysis (SEM/EPMA) and X-ray diffractometry (XRD). The hardness, adhesion strength and tribological properties of the coating were tested with a Vickers hardness tester, tensile tester and reciprocating wear tester, respectively. The composite coating, in which flattened WC/12Co was embedded in amorphous Fe 43 Cr 16 Mo 16 C 15 B 10 layers, exhibited high hardness, good wear resistance and a low friction coefficient compared to the monolithic coating. The addition of 8% WC/12Co to the Fe 43 Cr 16 Mo 16 C 15 B 10 matrix increased the cross-sectional hardness from 660 to 870 HV and reduced the friction coefficient from 0.65 to 0.5. WC/12Co reinforcement plays an important role in improving the tribological properties of the Fe 43 Cr 16 Mo 16 C 15 B 10 coating.

A theoretical and spectroscopic study of co-amorphous naproxen and indomethacin

DEFF Research Database (Denmark)

Löbmann, Korbinian; Laitinen, Riikka; Grohganz, Holger

2013-01-01

. In this study, the co-amorphous drug mixture containing naproxen (NAP) and indomethacin (IND) was investigated using infrared spectroscopy (IR) and quantum mechanical calculations. The structures of both drugs were optimized as monomer, homodimer and heterodimer using density functional theory and used...... for the calculation of IR spectra. Conformational analysis confirmed that the optimized structures were suitable for the theoretical prediction of the spectra. Vibrational modes from the calculation could be matched with experimentally observed spectra for crystalline and amorphous NAP and IND, and it could be shown...... that both drugs exist as homodimers in their respective individual amorphous form. With the results from the experimental single amorphous drugs and theoretical homodimers, a detailed analysis of the experimental co-amorphous and theoretical heterodimer spectra was performed and evaluated. It is suggested...

High thermal stability in W/MgO/CoFeB/W/CoFeB/W stacks via ultrathin W insertion with perpendicular magnetic anisotropy

Energy Technology Data Exchange (ETDEWEB)

Liu, Yi; Yu, Tao [School of Physics and Nuclear Energy Engineering, Beihang University, Beijing 100191 (China); Zhu, Zhengyong; Zhong, Huicai [Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029 (China); Khamis, Khamis Masoud [School of Physics and Nuclear Energy Engineering, Beihang University, Beijing 100191 (China); Zhu, Kaigui, E-mail: kgzhu@buaa.edu.cn [School of Physics and Nuclear Energy Engineering, Beihang University, Beijing 100191 (China); Key Laboratory of Micro-Nano Measurement-Manipulation and Physics, Ministry of Education, Beihang University, Beijing 100191 (China)

2016-07-15

The perpendicular magnetic anisotropy (PMA) of a series of top MgO/CoFeB/W stacks were studied. In these stacks, the thickness of CoFeB is limited in a range of 1.1–2.2 nm. It was found that the stack can still maintain PMA in a 1.9 nm thick CoFeB free layer. Besides, we investigated the thermal stability factor ∆ of a spin transfer torque magnetic random access memory (STT-MRAM) by inserting an ultra-thin W film of 0.8 nm between two CoFeB films. The result shows a clear PMA behavior for the samples with CoFeB thickness up to 2.5 nm, and an in-plane magnetic anisotropy (IMA) when the CoFeB is thicker than 2.5 nm. Moreover, the thermal stability factor ∆ of the CoFeB stack with W insertion is about 132 for a 50 nm size STT-MRAM device, which is remarkably improved compared to 112 for a sample without W insertion. Our results represent an alternative way to realize the endurance at high annealing temperature, high-density and high ∆ in STT-MRAM device by ultra-thin W insertion. - Highlights: • The MgO/CoFeB/W multilayer can still maintain PMA in a CoFeB thickness of 1.9 nm. • The sample with 2.5 nm thickness of CoFeB by W insertion can still maintain PMA. • The sample with W insertion can still maintain PMA until the annealing temperature as high as 350 °C. • The thermal stability factor ∆ of sample with W insertion could be increase to about 132 for a 50 nm size STT-MRAM device.

Highly hard yet toughened bcc-W coating by doping unexpectedly low B content

KAUST Repository

Yang, Lina

2017-08-18

Either hardness or toughness has been the core interest in scientific exploration and technological pursuit for a long time. However, it is still a big challenge to enhance the hardness and toughness at the same time, since the improvement of one side is always at the expense of the other one. Here, we have succeeded in dealing with this pair of conflict based on tungsten (W) coating by doping boron (B) via magnetron co-sputtering. The results reveal that the introduction of low concentrations of B (6.3 at. %), in the doping regime, leads to the formation of W(B) supersaturated solid solution with refined grains. Meanwhile, the doping-induced higher compressive stress, higher H/E* and denser microstructure result in a surprising combination of improved hardness (2 × larger than pure W) and superior toughness (higher crack formation threshold compared to pure W). We believe this is an innovative sight to design new generation of transition-metal-based multifunctional coatings. Besides, our results are applicable for industrial application because it can be realized by simple manufacturing approaches, e.g. magnetron sputtering technology.

Anti-biofouling function of amorphous nano-Ta2O5 coating for VO2-based intelligent windows

Science.gov (United States)

Li, Jinhua; Guo, Geyong; Wang, Jiaxing; Zhou, Huaijuan; Shen, Hao; Yeung, Kelvin W. K.

2017-04-01

From environmental and health perspectives, the acquisition of a surface anti-biofouling property holds important significance for the usability of VO2 intelligent windows. Herein, we firstly deposited amorphous Ta2O5 nanoparticles on VO2 film by the magnetron sputtering method. It was found that the amorphous nano-Ta2O5 coating possessed a favorable anti-biofouling capability against Pseudomonas aeruginosa as an environmental microorganism model, behind which lay the mechanism that the amorphous nano-Ta2O5 could interrupt the microbial membrane electron transport chain and significantly elevate the intracellular reactive oxygen species (ROS) level. A plausible relationship was established between the anti-biofouling activity and physicochemical nature of amorphous Ta2O5 nanoparticles from the perspective of defect chemistry. ROS-induced oxidative damage gave rise to microbial viability loss. In addition, the amorphous nano-Ta2O5 coating can endow VO2 with favorable cytocompatibility with human skin fibroblasts. This study may provide new insights into understanding the anti-biofouling and antimicrobial actions of amorphous transition metal oxide nanoparticles, which is conducive to expanding their potential applications in environmental fields.

Comparative study of the friction and wear behavior of plasma sprayed conventional and nanostructured WC-12%Co coatings on stainless steel

International Nuclear Information System (INIS)

Zhao Xiaoqin; Zhou Huidi; Chen Jianmin

2006-01-01

Conventional and nanostructured WC-12%Co coatings were deposited on 1Cr18Ni9Ti stainless steel substrate using air plasma spraying. The hardness of the coatings was measured, while their friction and wear behavior sliding against Si 3 N 4 at room temperature and elevated temperatures up to 400 deg. C was comparatively studied. The microstructures and worn surface morphologies of the coatings were comparatively analyzed as well by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray analysis (EDXA). It was found that the as-sprayed WC-12%Co coatings were composed of WC as the major phase and W 2 C, WC 1-x , and W 3 Co 3 C as the minor phases. The plasma sprayed nanostructured WC-12%Co coating had much higher hardness and refined microstructures than the conventional WC-12%Co coating. This largely accounted for the better wear resistance of the nanostructured WC-12%Co coating than the conventional coating. Besides, the two types of WC-12%Co coatings showed minor differences in friction coefficients, though the nanostructured WC-12%Co coating roughly had slightly smaller friction coefficient than the conventional coating under the same sliding condition. Moreover, both the conventional and nanostructured WC-12%Co coatings recorded gradually increased wear rate with increasing temperature, and the nanostructured coating was less sensitive to the temperature rise in terms of the wear resistance. The worn surfaces of the conventional WC-12%Co coating at different sliding conditions showed more severe adhesion, microfracture, and peeling as compared to the nanostructured WC-12%Co coating, which well conformed to the corresponding wear resistance of the two types of coatings. The nanostructured WC-12%Co coating with a wear rate as small as 1.01 x 10 -7 mm 3 /Nm at 400 deg. C could be promising candidate coating for the surface-modification of some sliding components subject to harsh working conditions involving elevated

Microwave assisted coating of bioactive amorphous magnesium phosphate (AMP) on polyetheretherketone (PEEK).

Science.gov (United States)

Ren, Yufu; Sikder, Prabaha; Lin, Boren; Bhaduri, Sarit B

2018-04-01

Polyetheretherketone (PEEK) with great thermal and chemical stability, desirable mechanical properties and promising biocompatibility is being widely used as orthopedic and dental implant materials. However, the bioinert surface of PEEK can hinder direct osseointegration between the host tissue and PEEK based implants. The important signatures of this paper are as follows. First, we report for the formation of osseointegrable amorphous magnesium phosphate (AMP) coating on PEEK surface using microwave energy. Second, coatings consist of nano-sized AMP particles with a stacked thickness of 800nm. Third, coatings enhance bioactivity in-vitro and induce significantly high amount of bone-like apatite coating, when soaked in simulated body fluid (SBF). Fourth, the as-deposited AMP coatings present no cytotoxicity effects and are beneficial for cell adhesion at early stage. Finally, the high levels of expression of osteocalcin (OCN) in cells cultured on AMP coated PEEK samples indicate that AMP coatings can promote new bone formation and hence osseointegration. Copyright © 2017 Elsevier B.V. All rights reserved.

Corrosion resistance and biocompatibility of titanium surface coated with amorphous tantalum pentoxide

Energy Technology Data Exchange (ETDEWEB)

Sun, Ying-Sui [Department of Oral Biology, National Yang-Ming University, Taipei, Taiwan (China); Chang, Jean-Heng [Dental Department, Cheng Hsin General Hospital, Taipei, Taiwan (China); Huang, Her-Hsiung, E-mail: hhhuang@ym.edu.tw [Department of Dentistry, National Yang-Ming University, Taipei, Taiwan (China); Department of Dentistry, Taipei City Hospital, Taipei, Taiwan (China); Department of Stomatology, Taipei Veterans General Hospital, Taipei, Taiwan (China)

2013-01-01

Tantalum pentoxide (Ta{sub 2}O{sub 5}) possesses good corrosion resistance and biocompatibility. This study aimed to improve the corrosion resistance and biocompatibility of titanium (Ti) by coating it with an amorphous Ta{sub 2}O{sub 5} surface layer. An amorphous Ta{sub 2}O{sub 5} layer was prepared on the Ti surface using a simple hydrolysis–condensation process at room temperature. The surface characteristics of the test specimens were analyzed using X-ray photoelectron spectroscopy, glancing angle X-ray diffraction, field emission scanning electron microscopy, and contact angle measurements. The corrosion resistance of the test specimens was evaluated from the potentiodynamic polarization curves and ion release measurements in simulated blood plasma (SBP). The biocompatibility of the test specimens was evaluated in terms of the protein (albumin) adsorption, cell adhesion, and cell growth of human bone marrow mesenchymal stem cells (hBMSCs). The amorphous Ta{sub 2}O{sub 5} layer with a porous micro-/nano-scale topography, which was deposited on the Ti surface using a simple hydrolysis–condensation process, increased the corrosion resistance (i.e., increased the corrosion potential and decreased the anodic current and ion release) of the Ti in the SBP and improved the surface wettability, albumin adsorption, and cell adhesion. We conclude that the presence of an amorphous Ta{sub 2}O{sub 5} layer on the Ti surface increased the corrosion resistance and biocompatibility of Ti. - Highlights: ► Amorphous Ta{sub 2}O{sub 5} layer was coated on Ti using simple hydrolysis–condensation process. ► Ta{sub 2}O{sub 5} surface layer showed a micro-/nano-scale porous topography. ► Ta{sub 2}O{sub 5} layer enhanced wettability and corrosion resistance of Ti. ► Ta{sub 2}O{sub 5} layer enhanced protein adsorption, cell adhesion, and cell proliferation of Ti.

Magnetism and local environment model in (Ni/sub 1-c/Co/sub c/)078P014B008 amorphous alloys

International Nuclear Information System (INIS)

Amamou, A.

1976-06-01

The magnetic properties of amorphous alloys (Ni/sub 1-c/Co/sub c/) 0 . 78 P 0 . 14 B 0 . 08 were investigated. The samples were prepared by the splat-cooling method. The Curie temperatures were determined and the magnetization measurements, performed for 1.7 0 K less than or equal to T less than or equal to 270 0 K and fields up to kOe. Ni 0 . 78 P 0 . 14 B 0 . 08 is paramagnetic, whereas Co 0 . 78 P 0 . 14 B 0 . 08 is ferromagnetic until the crystallization temperature (678 0 K). The average moment per cobalt atom is 1.15 μ/sub B/. In (Ni/sub 1-c/Co/sub c/) 0 . 78 P 0 . 14 B 0 . 08 the critical concentration for the paramagnetic-ferromagnetic transition is c approximately equal to 0.15; this transition occurs in an inhomogeneous way. The saturation magnetization in the whole concentration range can be interpreted (as for some crystallized alloys and compounds) by a local environment model, when a reasonable short-range order is assumed. In such a model the magnetic moment per cobalt atom is related merely to the number of its Co first neighbors n/sub Co/. For n/sub Co/ = 0 and 1 the cobalt atom is not magnetic, for n/sub Co/ = 2 and 3 it carries a small moment μ 1 = 0.50μ/sub B/ and for n/sub Co/ greater than 3 it is magnetic with μ 2 = 1.15μ/sub B/ as in Co 0 . 78 P 0 . 14 B 0 . 08 ; the nickel atoms do not carry a substantial moment in the entire concentration range. These features are comparable to those obtained in some crystalline alloys. 3 figures

Hollow Co2P nanoflowers organized by nanorods for ultralong cycle-life supercapacitors

KAUST Repository

Cheng, Ming; Fan, Hongsheng; Xu, Yingying; Wang, Rongming; Zhang, Xixiang

2017-01-01

Hollow Co2P nanoflowers (Co2P HNF) are successfully prepared via a one-step, template-free method. Microstructure analysis reveals that Co2P HNF is assembled by nanorods, possesses abundant mesopores and a amorphous carbon shell. Density functional

The effect of nanocrystalline Ni-W coating on the tensile properties of copper

Directory of Open Access Journals (Sweden)

E. P. Georgiou

2016-03-01

Full Text Available Nanostructured Ni-W alloy coatings containing approximately 40 wt.% tungsten were electrodeposited onto copper substrates. The effect of the coatings thickness on the surface topography, microstructure and grain size was investigated with the aid of Atomic Force Microscopy (AFM, Scanning Electron Microscopy (SEM and X-ray Diffraction (XRD techniques respectively. In addition, this research work aims in understanding the influence and correlation between microstructure and thickness of these Ni-W coatings with the bulk mechanical properties of coated specimens. The experimental results indicated that the micro-hardness and Ultimate Tensile Strength (UTS of the Ni-W coated copper were higher than that of bare copper, whereas both slightly increased with increasing coating thickness up to 21 μm. On the other hand, the ductility of Ni-W coated copper decreased significantly with increasing coating thickness. Thus it could be said that when applying Ni-W coatings there are certain limitations not only in terms of their composition, but their thickness, grain size and coating structure should be also taken into consideration, in order to obtain an understanding of their mechanical behavior.

Phosphorus-containing enamel type coatings on metals

International Nuclear Information System (INIS)

Sedmale, G.; Sedmalis, U.; Kpbjakov, V.

1998-01-01

Experimental data are given on development of temperature resistant glassy electroinsulating coatings for two groups of metals: niobium and its alloys and metals of the Fe-Co group. The development of the coatings is based on the system: BaO-B 2 O 3 (Al 2 O 3 )-SiO 2 -P 2 O 5 with content of P 2 O 5 up to 30 mol %. The formation process of coatings on metals proceeds via formation of intermediate layer with thickness of 4-6 m u m , which in the case of Nb-Zr coatings consists of dense crystalline aggregates, whose composition according to the x-ray phase analysis corresponds to NbP, Al 9 Nb,AlPO 4 , NbPO 3 . In the case Co-Fe alloys the intermediate layer is amorphous, the content of crystalline phases (CoFe 2 O 4 , Fe 2 O 3 ) is low (not more than 10 %). The latter does not significantly influence the magnetic properties of material and provides the electrical insulation at 550-666 deg C. In the case of protective coatings for Nb-Zr metals the formed intermediate layer and glassy surface layer (their total thickness being 40-60 m u m ) provide protection of the metals up to 1000 deg C in the period up to 1000 h. (author)

Coating of calcia-doped ceria with amorphous silica shell by seeded polymerization technique

International Nuclear Information System (INIS)

El-Toni, Ahmed Mohamed; Yin, Shu; Yabe, Shinryo; Sato, Tsugio

2005-01-01

Calcia-doped ceria is of potential interest as an ultraviolet (UV) radiation blocking material in personal care products. However, its high catalytic ability for oxidation of organic materials makes it difficult to use as a sunscreen material. Therefore, calcia-doped ceria was coated with amorphous silica by means of seeded polymerization technique in order to depress its oxidation catalytic ability. The catalytic ability as well as UV-shielding ability was investigated for coated particles

Multivariate Quantification of the Solid State Phase Composition of Co-Amorphous Naproxen-Indomethacin

Directory of Open Access Journals (Sweden)

Andreas Beyer

2015-10-01

Full Text Available To benefit from the optimized dissolution properties of active pharmaceutical ingredients in their amorphous forms, co-amorphisation as a viable tool to stabilize these amorphous phases is of both academic and industrial interest. Reports dealing with the physical stability and recrystallization behavior of co-amorphous systems are however limited to qualitative evaluations based on the corresponding X-ray powder diffractograms. Therefore, the objective of the study was to develop a quantification model based on X-ray powder diffractometry (XRPD, followed by a multivariate partial least squares regression approach that enables the simultaneous determination of up to four solid state fractions: crystalline naproxen, γ-indomethacin, α-indomethacin as well as co-amorphous naproxen-indomethacin. For this purpose, a calibration set that covers the whole range of possible combinations of the four components was prepared and analyzed by XRPD. In order to test the model performances, leave-one-out cross validation was performed and revealed root mean square errors of validation between 3.11% and 3.45% for the crystalline molar fractions and 5.57% for the co-amorphous molar fraction. In summary, even four solid state phases, involving one co-amorphous phase, can be quantified with this XRPD data-based approach.

Reactive diffusion in amorphous Fe-B and Co-Zr multilayer films

International Nuclear Information System (INIS)

Stobiecki, F.

1989-01-01

The diffusion in Fe 1-x B x /Fe 1-y B y and Co 1-x Zr x /Co 1-y Zr y amorphous bi- and multilayers was investigated. The dependence of the diffusion coefficient on concentration was observed. This effect is explained taking into account the concentration dependence of mixing enthalpy correlated with chemical short range order in the amorphous state

Viability of pHEMA Hydrogels as Coating in Human Synovial Joint Prosthesis

Directory of Open Access Journals (Sweden)

V.P. Bavaresco

2002-10-01

Full Text Available In artificial joints, the bone part is usually substituted by a metallic component with high corrosion and strength resistance while the articular cartilage is replaced by a polymer. Use of thin layer of a compliant material acting as a bearing surface in human replacement joints has recently generated considerable interest. This work analyses the coating of a solid porous substrate of Ultra High Molecular Weight Polyethylene (UHMWPE with a poly (2-hydroxyethyl methacrylate (pHEMA and two sIPN-type blends: pHEMA-cellulose acetate butyrate (CAB and pHEMA-poly (ethyl methacrylate (PEM using 5.0% (w/w of the crosslinking agent and 11.0% (w/w of the linear reinforcing polymer. The wear resistance of the coating materials was evaluated in a TRI PIN ON DISK type equipment and the damage extension was characterized by Scanning Electron Microscopy (SEM. Preliminary qualitative tests were performed with the goal to identifying the hydrogels show the minimal required properties concerning wear strength. The pHEMA coating was completely destroyed during the first wear cycles, characterizing its low shear strength. By the other hand, after the complete experiment, both pHEMA-CAB and pHEMA-PEM blends showed a slightly improvement of abrasive and adhesive wear. This result indicates that the studied blends are promising materials to be used as compliant surfaces in joint prosthesis.

Electrolytic Synthesis of Ni-W-MWCNT Composite Coating for Alkaline Hydrogen Evolution Reaction

Science.gov (United States)

Elias, Liju; Hegde, A. Chitharanjan

2018-03-01

Nickel-tungsten multi-walled carbon nanotube (Ni-W-MWCNT) composite films were fabricated by an electrodeposition technique, and their electrocatalytic activity toward hydrogen evolution reaction (HER) was studied. Ni-W-MWCNT composite films with a homogeneous dispersion of MWCNTs were deposited from an optimal Ni-W plating bath containing functionalized MWCNTs, under galvanostatic condition. The presence of functionalized MWCNT was found to enhance the induced codeposition of the reluctant metal W and resulted in a W-rich composite coating with improved properties. The electrocatalytic behaviors of Ni-W-MWCNT composite coating toward HER were studied by cyclic voltammetry (CV) and chronopotentiometry techniques in 1.0 M KOH medium. Further, Tafel polarization and electrochemical impedance spectroscopy (EIS) studies were carried out to establish the kinetics of HER on the alloy and composite electrodes. The experimental results revealed that the addition of MWCNTs (having a diameter of around 10-15 nm) into the alloy plating bath has a significant effect on the electrocatalytic behavior of Ni-W alloy deposit. The Ni-W-MWCNT composite coating was found to show better HER activity than the conventional Ni-W alloy coating. The enhanced electrocatalytic activity of Ni-W-MWCNT composite coating is attributed to the MWCNT intersticed in the deposit matrix, evidenced by surface morphology, composition and phase structure of the coating through SEM, EDS and XRD analyses, respectively.

Structure characterization of nanocrystalline Ni–W alloys obtained by electrodeposition

Energy Technology Data Exchange (ETDEWEB)

Indyka, P., E-mail: paulina.indyka@uj.edu.pl [Jagiellonian University, Faculty of Chemistry, 3 Ingardena St., 30-059 Krakow (Poland); Beltowska-Lehman, E.; Tarkowski, L.; Bigos, A. [Institute of Metallurgy and Materials Science, Polish Academy of Sciences, 25 Reymonta St., 30-059 Krakow (Poland); García-Lecina, E. [Surface Finishing Department, CIDETEC-IK4 – Centre for Electrochemical Technologies, P° Miramón 196, 20009 Donostia-San Sebastián (Spain)

2014-03-25

Highlights: • Ni–W alloy coatings were electrodeposited from an aqueous electrolyte solutions. • The microstructure was studied with respect to electrodeposition process parameters. • We report optimal plating conditions for crack-free, nanocrystalline Ni–W coatings. • Crystalline Ni–W coatings exhibited the phase structure of an α-Ni(W) solid solution. • Coatings revealed tensile residual stresses and weakly pronounced 〈1 1 0〉 fiber texture. -- Abstract: Ni–W coatings of different tungsten content (2–50 wt%) were electrodeposited on a steel substrates from an aqueous complex sulfate–citrate galvanic baths, under controlled hydrodynamic conditions in a Rotating Disk Electrode (RDE) system. The optimum conditions for the electrodeposition of crack-free, homogeneous nanocrystalline Ni–W coatings were determined on the basis of the microstructure investigation results. The XRD structural characterizations of Ni–W alloy coatings obtained under different experimental conditions were complemented by SEM and TEM analysis. Results of the study revealed that the main factor influencing the microstructure formation of the Ni–W coatings is the chemical composition of an electrolyte solution. X-ray and electron diffraction patterns of all nanocrystalline Ni–W coatings revealed mainly the fcc phase structure of an α-Ni(W) solid solution with a lattice parameter increased along with tungsten content. The use of additives in the plating bath resulted in the formation of equiaxial/quasifibrous, nanocrystalline Ni–W grains of an average size of about 10 nm. The coatings were characterized by relatively high tensile residual stresses (500–1000 MPa), depending on the electrodeposition conditions. Ni–W coatings exhibited weakly pronounced fiber type 〈1 1 0〉 crystallographic texture, consistent with the symmetry of the plating process. Coatings of the highest tungsten content 50 wt% were found to be amorphous.

Laser deposition of SmCo thin film and coating on different substrates

International Nuclear Information System (INIS)

Allocca, L; Bonavolonta, C; Valentino, M; Giardini, A; Lopizzo, T; Morone, A; Verrastro, M F; Viggiano, V

2008-01-01

Thin films and coatings of permanent magnetic materials are very important for different electronic and micromechanical applications. This paper deals with the fabrication, using pulsed laser deposition (PLD) technique, of good quality magnetic SmCo thin films on polycarbonate, steel, silicon and amorphous quartz substrates, for low cost electronic applications like radio frequency identification (RFID) antennas and electromechanical devices for fuel feeding control in the automotive. X-ray fluorescence and magnetic scanning measurements using giant magneto-resistive (GMR) sensors have been performed to study the functional magnetic properties of the deposited thin films.

Syntheses and characterization of TiC/a:C composite coatings using pulsed closed field unbalanced magnetron sputtering (P-CFUBMS)

International Nuclear Information System (INIS)

Lin, J.; Moore, J.J.; Mishra, B.; Pinkas, M.; Sproul, W.D.

2008-01-01

TiC/a:C nanocomposite coatings were prepared by reactively sputtering titanium and graphite targets in pure argon atmosphere using a pulsed closed field unbalanced magnetron sputtering (P-CFUBMS) system. The microstructure of TiC/a:C coatings consisting of nanocrystalline TiC dispersed in an amorphous matrix of free carbon was investigated using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). The effects of coating compositions on the structure and properties of TiC/a:C coatings were investigated. In the present study, TiC/a:C coatings exhibit high hardness (24-29 GPa), low coefficient of friction (0.24-0.25) and low wear rate (less than 2.5 x 10 -7 mm 3 N -1 m -1 ) when the carbon concentration is in the range of 55-66 at.%. Further increase of the carbon content beyond 70 at.% significantly decreased the volume fraction of TiC nanocrystalline and formed a large amount of free amorphous carbon in the coatings. The excessive amorphous carbon phases resulted in a decrease in the coating hardness and the sliding friction coefficient, e.g. a low COF of 0.15 was obtained when the carbon concentration reached 80.5 at.%. However, the decreased hardness will lead to an increase in the wear rate in these high carbon content TiC/a:C coatings

Performance comparison between crystalline and co-amorphous salts of indomethacin-lysine

DEFF Research Database (Denmark)

Kasten, Georgia; Nouri, Khatera; Grohganz, Holger

2017-01-01

The introduction of a highly water soluble amino acid as co-amorphous co-former has previously been shown to significantly improve the dissolution rate of poorly water soluble drugs. In this work, dry ball milling (DBM) and liquid assisted grinding (LAG) were used to prepare different physical...... forms of salts of indomethacin (IND) with the amino acid lysine (LYS), allowing the direct comparison of their solid-state properties to their in vitro performance. X-ray powder diffraction and Fourier-transformed infrared spectroscopy showed that DBM experiments led to the formation of a fully co......-amorphous salt, while LAG resulted in a crystalline salt. Differential scanning calorimetry showed that the samples prepared by DBM had a single glass transition temperature (Tg) of approx. 100°C for the co-amorphous salt, while a new melting point (223°C) was obtained for the crystalline salt prepared by LAG...

Tribological Performance Optimization of Electroless Ni-P-W Coating Using Weighted Principal Component Analysis

Directory of Open Access Journals (Sweden)

S. Roy

2013-12-01

Full Text Available The present investigation is an experimental approach to deposit electroless Ni-P-W coating on mild steel substrate and find out the optimum combination of various tribological performances on the basis of minimum friction and wear, using weighted principal component analysis (WPCA. In this study three main tribological parameters are chosen viz. load (A, speed (B and time(C. The responses are coefficient of friction and wear depth. Here Weighted Principal Component Analysis (WPCA method is adopted to convert the multi-responses into single performance index called multiple performance index (MPI and Taguchi L27 orthogonal array is used to design the experiment and to find the optimum combination of tribological parameters for minimum coefficient of friction and wear depth. ANOVA is performed to find the significance of the each tribological process parameters and their interactions. The EDX analysis, SEM and XRD are performed to study the composition and structural aspects.

Influence of Solvent Composition on the Performance of Spray-Dried Co-Amorphous Formulations

DEFF Research Database (Denmark)

Mishra, Jaya; Rades, Thomas; Löbmann, Korbinian

2018-01-01

Ball-milling is usually used to prepare co-amorphous drug–amino acid (AA) mixtures. In this study, co-amorphous drug–AA mixtures were produced using spray-drying, a scalable industrially preferred preparation method. The influence of the solvent type and solvent composition was investigated....... Mixtures of indomethacin (IND) and each of the three AAs arginine, histidine, and lysine were ball-milled and spray-dried at a 1:1 molar ratio, respectively. Spray-drying was performed at different solvent ratios in (a) ethanol and water mixtures and (b) acetone and water mixtures. Different ratios...... that using spray-drying as a preparation method, all IND–AA mixtures could be successfully converted into the respective co-amorphous forms, irrespective of the type of solvent used, but depending on the solvent mixture ratios. Both ball-milled and spray-dried co-amorphous samples showed an enhanced...

Stress impedance effects in flexible amorphous FeCoSiB magnetoelastic films

International Nuclear Information System (INIS)

Zhang Wanli; Peng Bin; Su Ding; Tang Rujun; Jiang Hongchuan

2008-01-01

Amorphous FeCoSiB films were deposited on the flexible polyimide substrates (Kapton type (VN)) by DC magnetron sputtering. Stress impedance (SI) effects of the flexible amorphous FeCoSiB magnetoelastic films were investigated in details. The results show that a large stress impedance effect can be observed in the flexible amorphous FeCoSiB magnetoelastic films. And the results also show a bias magnetic field plays an important role in the stress impedance of FeCoSiB films. Applied a bias magnetic field during depositing can induce obvious in-plane anisotropy in the FeCoSiB films, and a larger SI effect can be obtained with a stronger anisotropy in FeCoSiB films. Argon pressure has a significant effect on the SI effect of the FeCoSiB films. The SI of the FeCoSiB films reaches a maximum of 7.6% at argon pressure of 1.5 Pa, which can be explained by the change of residual stress in FeCoSiB films

FIRST INFRARED BAND STRENGTHS FOR AMORPHOUS CO{sub 2}, AN OVERLOOKED COMPONENT OF INTERSTELLAR ICES

Energy Technology Data Exchange (ETDEWEB)

Gerakines, Perry A.; Hudson, Reggie L., E-mail: Reggie.Hudson@NASA.gov [Astrochemistry Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

2015-08-01

Solid carbon dioxide (CO{sub 2}) has long been recognized as a component of both interstellar and solar system ices, but a recent literature search has revealed significant qualitative and quantitative discrepancies in the laboratory spectra on which the abundances of extraterrestrial CO{sub 2} are based. Here we report new infrared (IR) spectra of amorphous CO{sub 2}-ice along with band intensities (band strengths) of four mid-IR absorptions, the first such results in the literature. A possible thickness dependence for amorphous-CO{sub 2} IR band shapes and positions also is investigated, and the three discordant reports of amorphous CO{sub 2} spectra in the literature are addressed. Applications of our results are discussed with an emphasis on laboratory investigations and results from astronomical observations. A careful comparison with earlier work shows that the IR spectra calculated from several databases for CO{sub 2} ices, all ices being made near 10 K, are not for amorphous CO{sub 2}, but rather for crystalline CO{sub 2} or crystalline-amorphous mixtures.

Effects of lithium-active manganese trioxide coating on the structural and electrochemical characteristics of LiNi_0_._5Co_0_._2Mn_0_._3O_2 as cathode materials for lithium ion battery

International Nuclear Information System (INIS)

Li, Lingjun; Yao, Qi; Chen, Zhaoyong; Song, Liubin; Xie, Tian; Zhu, Huali; Duan, Junfei; Zhang, Kaili

2015-01-01

Li_2MnO_3-coated LiNi_0_._5Co_0_._2Mn_0_._3O_2 materials are successfully synthesized by sol–gel method. The effects of various pH values and Li_2MnO_3 contents on the structural and electrochemical properties of LiNi_0_._5Co_0_._2Mn_0_._3O_2 cathode materials are systematically investigated, respectively. Scanning electron microscope, transmission electron microscope and energy dispersive spectrometer confirm that the particles of LiNi_0_._5Co_0_._2Mn_0_._3O_2 are completely coated by crystalline Li_2MnO_3 phase. Electrochemical tests show that suitable Li_2MnO_3-coated samples exhibit higher rate capacity and better cycling performance than those of the pristine one. This improvement can be attributed to the synergetic contribution from the neutral pH value and appropriate Li_2MnO_3 amount. The neutral pH environment can protect the core material from damaging during the coating process and is conducive to relieving the rapid moisture uptaking problem of LiNi_0_._5Co_0_._2Mn_0_._3O_2. While, suitable Li_2MnO_3 coating can protect the bulk from directly contacting the electrolyte and offer a fast Li"+ diffusion path at the interface of bulk and electrolyte. - Graphical abstract: The 5% Li_2MnO_3-coated LiNi_0_._5Co_0_._2Mn_0_._3O_2 sample, modified at pH 6, exhibits a conformal and amorphous coating layer before calcination. After been sintered at 880 °C for 5 h, the sample shows Li_2MnO_3 crystalline surface, as well as superior electrochemical performance. - Highlights: • Li_2MnO_3-coated LiNi_0_._5Co_0_._2Mn_0_._3O_2 is prepared by sol–gel method. • Neutral pH environment can protect NMC from damaging during the coating process. • Li_2MnO_3 coating enhances the pristine at high cyclability and rate properties. • Suitable Li_2MnO_3 modification results in better Li"+ diffusion coefficient. • The 5% Li_2MnO_3-coated sample exhibits the best electrochemical performance.

Electroless Ni-P/Ni-B duplex coatings: preparation and evaluation of microhardness, wear and corrosion resistance

International Nuclear Information System (INIS)

Narayanan, T.S.N. Sankara; Krishnaveni, K.; Seshadri, S.K.

2003-01-01

The present work deals with the formation of Ni-P/Ni-B duplex coatings by electroless plating process and evaluation of their hardness, wear resistance and corrosion resistance. The Ni-P/Ni-B duplex coatings were prepared using dual baths (acidic hypophosphite- and alkaline borohydride-reduced electroless nickel baths) with both Ni-P and Ni-B as inner layers and with varying single layer thickness. Scanning electron microscopy (SEM) was used to assess the duplex interface. The microhardness, wear resistance and corrosion resistance of electroless nickel duplex coatings were compared with electroless Ni-P and Ni-B coatings of similar thickness. The study reveals that the Ni-P and Ni-B coatings are amorphous in their as-plated condition and upon heat-treatment at 450 deg. C for 1 h, both Ni-P and Ni-B coatings crystallize and produce nickel, nickel phosphide and nickel borides in the respective coatings. All the three phases are formed when Ni-P/Ni-B and Ni-B/Ni-P duplex coatings are heat-treated at 450 deg. C for 1 h. The duplex coatings are uniform and the compatibility between the layers is good. The microhardness, wear resistance and corrosion resistance of the duplex coating is higher than Ni-P and Ni-B coatings of similar thickness. Among the two types of duplex coatings studied, hardness and wear resistance is higher for coatings having Ni-B coating as the outer layer whereas better corrosion resistance is offered by coatings having Ni-P coating as the outer layer

Possibility for hole doping into amorphous InGaZnO4 films prepared by RF sputtering

International Nuclear Information System (INIS)

Kobayashi, Kenkichiro; Kohno, Yoshiumi; Tomita, Yasumasa; Maeda, Yasuhisa; Matsushima, Shigenori

2011-01-01

Amorphous InGaZnO 4 (IGZO) films codoped with Al and N atoms were prepared by sputtering of targets consisting of IGZO and AlN powders in Ar + O 2 atmospheres. No hole-conductivity is seen in films deposited at 2 x 10 -3 Torr, whereas hole-conductivity is found in films deposited at 2 x 10 -2 Torr at radio frequency powers of 60-80 W in 0.3-0.6% O 2 atmospheres. The amorphous p-type IGZO film has the resistivity of 210 Wcm, hole-density of 7.5 x 10 17 cm -3 , and mobility of 0.4 cm 2 /Vs. The rectification characteristic is obtained for a device constructed from Au, amorphous p-type IGZO, and amorphous n-type IGZO. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Improving co-amorphous drug formulations by the addition of the highly water soluble amino acid proline

DEFF Research Database (Denmark)

Jensen, Katrine Birgitte Tarp; Löbmann, Korbinian; Rades, Thomas

2014-01-01

Co-amorphous drug amino acid mixtures were previously shown to be a promising approach to create physically stable amorphous systems with the improved dissolution properties of poorly water-soluble drugs. The aim of this work was to expand the co-amorphous drug amino acid mixture approach...... by combining the model drug, naproxen (NAP), with an amino acid to physically stabilize the co-amorphous system (tryptophan, TRP, or arginine, ARG) and a second highly soluble amino acid (proline, PRO) for an additional improvement of the dissolution rate. Co-amorphous drug-amino acid blends were prepared...... the molecular interactions in the form of hydrogen bonds between all three components in the mixture. A salt formation between the acidic drug, NAP, and the basic amino acid, ARG, was found in co-amorphous NAP–ARG. In comparison to crystalline NAP, binary NAP–TRP and NAP–ARG, it could be shown that the highly...

High-Performance Corrosion-Resistant Materials: Iron-Based Amorphous-Metal Thermal-Spray Coatings

International Nuclear Information System (INIS)

Farmer, J C; Haslam, J J; Wong, F; Ji, X; Day, S D; Branagan, D J; Marshall, M C; Meacham, B E; Buffa, E J; Blue, C A; Rivard, J K; Beardsley, M B; Weaver, D T; Aprigliano, L F; Kohler, L; Bayles, R; Lemieux, E J; Wolejsza, T M; Martin, F J; Yang, N; Lucadamo, G; Perepezko, J H; Hildal, K; Kaufman, L; Heuer, A H; Ernst, F; Michal, G M; Kahn, H; Lavernia, E J

2004-01-01

The multi-institutional High Performance Corrosion Resistant Materials (HPCRM) Team is cosponsored by the Defense Advanced Projects Agency (DARPA) Defense Science Office (DSO) and the Department of Energy (DOE) Office of Civilian Radioactive Waste Management (OCRWM), and has developed new corrosion-resistant, iron-based amorphous metals that can be applied as coatings with advanced thermal spray technology. Two compositions have corrosion resistance superior to wrought nickel-based Alloy C-22 (UNS No. N06022) in very aggressive environments, including concentrated calcium-chloride brines at elevated temperature. Corrosion costs the Department of Defense billions of dollars every year, with an immense quantity of material in various structures undergoing corrosion. For example, in addition to fluid and seawater piping, ballast tanks, and propulsions systems, approximately 345 million square feet of structure aboard naval ships and crafts require costly corrosion control measures. The use of advanced corrosion-resistant materials to prevent the continuous degradation of this massive surface area would be extremely beneficial. The Fe-based corrosion-resistant, amorphous-metal coatings under development may prove of importance for applications on ships. Such coatings could be used as an ''integral drip shield'' on spent fuel containers, as well as protective coatings that could be applied over welds, thereby preventing exposure to environments that might cause stress corrosion cracking. In the future, such new high-performance iron-based materials could be substituted for more-expensive nickel-based alloys, thereby enabling a reduction in the $58-billion life cycle cost for the long-term storage of the Nation's spent nuclear fuel by tens of percent

In situ photodeposition of amorphous CoSx on the TiO2 towards hydrogen evolution

Science.gov (United States)

Chen, Feng; Luo, Wei; Mo, Yanping; Yu, Huogen; Cheng, Bei

2018-02-01

Cocatalyst modification of photocatalysts is an important strategy to enhance the photocatalytic performance by promoting effective separation of photoinduced electron-hole pairs and providing abundant active sites. In this study, a facile in situ photodeposition method was developed to prepare amorphous CoSx-modified TiO2 photocatalysts. It was found that amorphous CoSx nanoparticles were solidly loaded on the TiO2 surface, resulting in a greatly improved photocatalytic H2-evolution performance. When the amount of amorphous CoSx was 10 wt%, the hydrogen evolution rate of the CoSx/TiO2 reached 119.7 μmol h-1, which was almost 16.7 times that of the pure TiO2. According to the above experimental results, a reasonable mechanism of improved photocatalytic performance is proposed for the CoSx/TiO2 photocatalysts, namely, the photogenerated electrons of TiO2 can rapidly transfer to amorphous CoSx nanoparticles due to the solid contact between them, and then amorphous CoSx can provide plenty of sulfur active sites to rapidly adsorb protons from solution to produce hydrogen by the photogenerated electrons. Considering the facile synthesis method, the present cheap and highly efficient amorphous CoSx-modified TiO2 photocatalysts would have great potential for practical use in photocatalytic H2 production.

Microstructure and tribological property of nanocrystalline Co–W alloy coating produced by dual-pulse electrodeposition

International Nuclear Information System (INIS)

Su Fenghua; Huang Ping

2012-01-01

Highlights: ► The nanocrystalline Co–W alloy coating were produced by dual-pulse electrodeposition from aqueous bath with cobalt sulfate and sodium tungstate. ► The correlation between the electrodeposition condition, the microstructure and alloy composition, and the hardness and tribological properties of electrodeposited Co–W alloy coatings were established. ► By careful control of the electrodeposition condition and the bath composition, the Co–W alloy coating excellent performance of microhardness and tribological properties, can exhibit excellent performances of microhardness and tribological properties. - Abstract: The nanocrystalline Co–W alloy coatings were produced by dual-pulse electrodeposition from aqueous bath with cobalt sulfate and sodium tungstate (Na 2 WO 4 ). Influence of the current density and Na 2 WO 4 concentration in bath on the microstructure, morphology and hardness of the Co–W alloy coatings were investigated using an X-ray diffraction, a scanning electronic microscope and a Vickers hardness tester, respectively. In addition, the friction and wear properties of the Co–W alloy coating electrodeposited under different condition were evaluated with a ball-on-disk UMT-3MT tribometer. The correlation between the electrodeposition condition, the microstructure and alloy composition, and the hardness and tribological properties of the deposited Co–W alloy coatings were discussed in detail. The results showed that the microhardness of the deposited Co–W alloy coating was significantly affected by its average grain size, W content and crystal orientation. Smaller grain size, higher W content and strong hcp (1 0 0) orientation favor the improvement of the hardness for Co–W alloy coatings. The deposited Co–W alloy coating could obtain the maximum microhardness over 1000 kgf mm −2 by careful control of the electrodeposition conditions. The tribological properties of the electrodeposited Co–W alloy coating were greatly

Amorphous clusters in Co implanted ZnO induced by boron pre-implantation

Energy Technology Data Exchange (ETDEWEB)

Potzger, K.; Shalimov, A.; Zhou, S.; Schmidt, H.; Mucklich, A.; Helm, M.; Fassbender, J.; Liberati, M.; Arenholz, E.

2009-02-09

We demonstrate the formation of superparamagnetic/ferromagnetic regions within ZnO(0001) single crystals sequently implanted with B and Co. While the pre-implantation with B plays a minor role for the electrical transport properties, its presence leads to the formation of amorphous phases. Moreover, B acts strongly reducing on the implanted Co. Thus, the origin of the ferromagnetic ordering in local clusters with large Co concentration is itinerant d-electrons as in the case of metallic Co. The metallic amorphous phases are non-detectable by common X-ray diffraction.

Study of the mechanical and magnetic properties of Fe{sub 61}Co{sub 10}Zr{sub 5-x}Hf{sub x}W{sub 2}Y{sub 2}B{sub 20} (x = 0 or 3) bulk amorphous and crystalline alloys

Energy Technology Data Exchange (ETDEWEB)

Nabialek, Marcin G. [Institute of Physics, Czestochowa University of Technology, 19 Armii Krajowej Av., 42-200 Czestochowa (Poland); Szota, Michal [Institute of Materials Engineering, Czestochowa University of Technology, 19 Armii Krajowej Av., 42-200 Czestochowa (Poland); Dospial, Marcin J.

2010-05-15

The microstructure, thermal stability, mechanical and magnetic properties of Fe{sub 61}Co{sub 10}Zr{sub 5-x}Hf{sub x}W{sub 2}Y{sub 2}B{sub 20} (where x = 0 or 3) bulk metallic glasses (BMG) and their crystalline equivalents were investigated. The crystalline materials were smelted on a copper mould using an electric arc; their amorphous equivalents were prepared using the induction suction casting method (ISC). All samples investigated were in the form of plates with dimensions of 10x10x0.5mm. From X-ray diffraction and Moessbauer spectroscopy, it was found that both investigated alloys prepared using this method have an amorphous structure. From magnetic measurements obtained by a vibrating sample magnetometer (VSM), it was shown that all measured samples displayed soft magnetic properties with relatively high saturation of the magnetization. The thermal stability and glass-forming ability (GFA) for investigated alloys were derived from differential scanning calorimetry (DSC) curves. The measurements of mechanical properties for amorphous alloys were found to be better than those for crystalline alloys with the same atomic composition. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Synthesis and electrochemical performances of amorphous carbon-coated Sn-Sb particles as anode material for lithium-ion batteries

International Nuclear Information System (INIS)

Wang Zhong; Tian Wenhuai; Liu Xiaohe; Yang Rong; Li Xingguo

2007-01-01

The amorphous carbon coating on the Sn-Sb particles was prepared from aqueous glucose solutions using a hydrothermal method. Because the outer layer carbon of composite materials is loose cotton-like and porous-like, it can accommodate the expansion and contraction of active materials to maintain the stability of the structure, and hinder effectively the aggregation of nano-sized alloy particles. The as-prepared composite materials show much improved electrochemical performances as anode materials for lithium-ion batteries compared with Sn-Sb alloy and carbon alone. This amorphous carbon-coated Sn-Sb particle is extremely promising anode materials for lithium secondary batteries and has a high potentiality in the future use. - Graphical abstract: The amorphous carbon coating on the Sn-Sb particles was prepared from aqueous glucose solutions using a hydrothermal method. Because the outer layer carbon of composite materials is loose cotton-like and porous-like, it can accommodate the expansion and contraction of active materials to maintain the stability of the structure, and hinder effectively the aggregation of nano-sized alloy particles

The emissivity of W coatings deposited on carbon materials for fusion applications

International Nuclear Information System (INIS)

Ruset, C.; Falie, D.; Grigore, E.; Gherendi, M.; Zoita, V.; Zastrow, K.-D.; Matthews, G.; Courtois, X.; Bucalossi, J.; Likonen, J.

2017-01-01

Highlights: • The emissivity of tungsten coatings deposited on carbon substrates such as CFC and fine grain graphite was measured at the wavelengths of 1.064 μm, 1.75 μm, 3.75 μm and 4.0 μm in the temperature range of 400 °C–1200 °C. • The emissivity of other materials of interest for nuclear fusion such as tungsten and beryllium was measured as well. • The influence of substrate structure and of the viewing angle on the emissivity of W coatings was investigated in detail. - Abstract: Tungsten coatings deposited on carbon materials such as carbon fiber composite (CFC) or fine grain graphite are currently used in fusion devices as amour for plasma facing components (PFC). More than 4000 carbon tiles were W-coated by Combined Magnetron Sputtering and Ion Implantation technology for the ITER-like Wall at JET, ASDEX Upgrade and WEST tokamaks. The emissivity of W coatings is a key parameter required by protection systems of the W-coated PFC and also by the diagnostic tools in order to get correct values of temperature and heat loading. The emissivity of tungsten is rather well known, but the literature data refer to bulk tungsten or tungsten foils and not to coatings deposited on carbon materials. The emissivity was measured at the wavelengths of 1.064 μm, 1.75 μm, 3.75 μm and 4.0 μm. It was found that the structure of the substrate has a significant influence on the emissivity values. The temperature dependence of the emissivity in the range of 400 °C–1200 °C and the influence of the viewing angle were investigated as well. The results are given in a table for W coatings and for other materials of interest for fusion such as bulk W and bulk Be.

The emissivity of W coatings deposited on carbon materials for fusion applications

Energy Technology Data Exchange (ETDEWEB)

Ruset, C., E-mail: ruset@infim.ro [National Institute for Laser, Plasma and Radiation Physics, 077125 Bucharest (Romania); Falie, D.; Grigore, E.; Gherendi, M.; Zoita, V. [National Institute for Laser, Plasma and Radiation Physics, 077125 Bucharest (Romania); Zastrow, K.-D.; Matthews, G. [Culham Centre for Fusion Energy (CCFE), Culham Science Centre, Abingdon (United Kingdom); Courtois, X.; Bucalossi, J. [IRFM, CEA Cadarache, F-13108 SAINT PAUL LEZ DURANCE (France); Likonen, J. [VTT Technical Research Centre of Finland, P.O. Box 1000, FI-02044 VTT (Finland)

2017-01-15

Highlights: • The emissivity of tungsten coatings deposited on carbon substrates such as CFC and fine grain graphite was measured at the wavelengths of 1.064 μm, 1.75 μm, 3.75 μm and 4.0 μm in the temperature range of 400 °C–1200 °C. • The emissivity of other materials of interest for nuclear fusion such as tungsten and beryllium was measured as well. • The influence of substrate structure and of the viewing angle on the emissivity of W coatings was investigated in detail. - Abstract: Tungsten coatings deposited on carbon materials such as carbon fiber composite (CFC) or fine grain graphite are currently used in fusion devices as amour for plasma facing components (PFC). More than 4000 carbon tiles were W-coated by Combined Magnetron Sputtering and Ion Implantation technology for the ITER-like Wall at JET, ASDEX Upgrade and WEST tokamaks. The emissivity of W coatings is a key parameter required by protection systems of the W-coated PFC and also by the diagnostic tools in order to get correct values of temperature and heat loading. The emissivity of tungsten is rather well known, but the literature data refer to bulk tungsten or tungsten foils and not to coatings deposited on carbon materials. The emissivity was measured at the wavelengths of 1.064 μm, 1.75 μm, 3.75 μm and 4.0 μm. It was found that the structure of the substrate has a significant influence on the emissivity values. The temperature dependence of the emissivity in the range of 400 °C–1200 °C and the influence of the viewing angle were investigated as well. The results are given in a table for W coatings and for other materials of interest for fusion such as bulk W and bulk Be.

Salt Fog Testing Iron-Based Amorphous Alloys

International Nuclear Information System (INIS)

Rebak, Raul B.; Aprigliano, Louis F.; Day, S. Daniel; Farmer, Joseph C.

2007-01-01

Iron-based amorphous alloys are hard and highly corrosion resistant, which make them desirable for salt water and other applications. These alloys can be produced as powder and can be deposited as coatings on any surface that needs to be protected from the environment. It was of interest to examine the behavior of these amorphous alloys in the standard salt-fog testing ASTM B 117. Three different amorphous coating compositions were deposited on 316L SS coupons and exposed for many cycles of the salt fog test. Other common engineering alloys such as 1018 carbon steel, 316L SS and Hastelloy C-22 were also tested together with the amorphous coatings. Results show that amorphous coatings are resistant to rusting in salt fog. Partial devitrification may be responsible for isolated rust spots in one of the coatings. (authors)

Corrosion resistant amorphous metals and methods of forming corrosion resistant amorphous metals

Science.gov (United States)

Farmer, Joseph C [Tracy, CA; Wong, Frank M. G. [Livermore, CA; Haslam, Jeffery J [Livermore, CA; Yang, Nancy [Lafayette, CA; Lavernia, Enrique J [Davis, CA; Blue, Craig A [Knoxville, TN; Graeve, Olivia A [Reno, NV; Bayles, Robert [Annandale, VA; Perepezko, John H [Madison, WI; Kaufman, Larry [Brookline, MA; Schoenung, Julie [Davis, CA; Ajdelsztajn, Leo [Walnut Creek, CA

2009-11-17

A system for coating a surface comprises providing a source of amorphous metal, providing ceramic particles, and applying the amorphous metal and the ceramic particles to the surface by a spray. The coating comprises a composite material made of amorphous metal that contains one or more of the following elements in the specified range of composition: yttrium (.gtoreq.1 atomic %), chromium (14 to 18 atomic %), molybdenum (.gtoreq.7 atomic %), tungsten (.gtoreq.1 atomic %), boron (.ltoreq.5 atomic %), or carbon (.gtoreq.4 atomic %).

Effect of Si on the glass-forming ability, thermal stability and magnetic properties of Fe-Co-Zr-Mo-W-B alloys

Energy Technology Data Exchange (ETDEWEB)

Wang, W.-M. [Institute for Metallic Materials, IFW Dresden, P.O. 270016, Dresden D-01171 (Germany); Key Lab of Liquid Structure and Heredity of Materials, Shandong University, Jinan 250061 (China); Gebert, A. [Institute for Metallic Materials, IFW Dresden, P.O. 270016, Dresden D-01171 (Germany)], E-mail: a.gebert@ifw-dresden.de; Roth, S.; Kuehn, U.; Schultz, L. [Institute for Metallic Materials, IFW Dresden, P.O. 270016, Dresden D-01171 (Germany)

2008-07-14

This paper presents investigations on the effect of Si on the glass-forming ability, thermal stability and magnetic properties of the Fe-Co-Zr-Mo-W-B samples (group I: Fe{sub 60}Co{sub 8}Zr{sub 10}Mo{sub 5}W{sub 2}B{sub 15-x}Si{sub x}, 1 {<=} x {<=} 4; group II: Fe{sub 60}Co{sub 8}Zr{sub 10-x}Mo{sub 5}W{sub 2}B{sub 15}Si{sub x}, 0 {<=} x {<=} 4; group III: Fe{sub 60}Co{sub 8}Zr{sub 8}Mo{sub 5}W{sub 2}B{sub 17-x}Si{sub x}, 0 {<=} x {<=} 2) prepared by melt spinning, injection casting, and centrifugal casting methods. It is found that the glass-forming ability (GFA) of the alloys in group I is more deteriorated than that in group II, and that the alloys in group III can be cast into the rods of 1-3 mm diameter without crystalline reflections in their XRD patterns. For the amorphous ribbons and rods, a non-monotonic change of the nearest neighbour distance r{sub 1} with increasing Si content c{sub Si} was detected, which is parallel to that of the glass transition and crystallization temperatures T{sub g} and T{sub x}, but opposite to that of the magnetization at room temperature M{sub RT} and the Curie temperature T{sub c}. This correlation can be interpreted by a structure model presuming that iron atoms appear simultaneously in two types of local structures in the amorphous samples.

A comparison of degradation in three amorphous silicon PV module technologies

Energy Technology Data Exchange (ETDEWEB)

Radue, C.; van Dyk, E.E. [Physics Department, PO Box 77000, Nelson Mandela Metropolitan University, Port Elizabeth 6031 (South Africa)

2010-03-15

Three commercial amorphous silicon modules manufactured by monolithic integration and consisting of three technology types were analysed in this study. These modules were deployed outdoors for 14 months and underwent degradation. All three modules experienced the typical light-induced degradation (LID) described by the Staebler-Wronski effect, and this was followed by further degradation. A 14 W single junction amorphous silicon module degraded by about 45% of the initial measured maximum power output (P{sub MAX}) at the end of the study. A maximum of 30% of this has been attributed to LID and the further 15% to cell mismatch and cell degradation. The other two modules, a 64 W triple junction amorphous silicon module, and a 68 W flexible triple junction amorphous silicon module, exhibited LID followed by seasonal variation in the degraded P{sub MAX}. The 64 W module showed a maximum degradation in P{sub MAX} of about 22%. This is approximately 4% more than the manufacturer allowed for the initial LID. However, the seasonal variation in P{sub MAX} seems to be centred around the manufacturer's rating ({+-}4%). The 68 W flexible module has shown a maximum decrease in P{sub MAX} of about 27%. This decrease is about 17% greater than the manufacturer allowed for the initial LID. (author)

Structure of multilayered Cr(Al)N/SiO{sub x} nanocomposite coatings fabricated by differential pumping co-sputtering

Energy Technology Data Exchange (ETDEWEB)

Kawasaki, Masahiro [JEOL USA Inc., 11 Dearborn Road, Peabody, Massachusetts 01960 (United States); Nose, Masateru [Faculty of Art and Design, University of Toyama, 180 Futagami-machi, Takaoka 933-8588 (Japan); Onishi, Ichiro [JEOL Ltd. 3-1-2 Musashino, Akishima, Tokyo 196-8558 (Japan); Shiojiri, Makoto [Kyoto Institute of Technology, Kyoto 606-8585 (Japan)

2013-11-11

A Cr(Al)N/38 vol. % SiO{sub x} hard coating was prepared on a (001) Si substrate at 250 °C in a differential pumping co-sputtering system, which has two chambers for radio frequency (RF) sputtering and a substrate holder rotating on the chambers. The composite coating was grown by alternate sputter-depositions from CrAl and SiO{sub 2} targets with flows of N{sub 2}+Ar and Ar at RF powers of 200 and 75 W, respectively, on transition layers grown on the substrate. Analytical electron microscopy reveled that the Cr(Al)N/SiO{sub x} coating had a multilayered structure of Cr(Al)N crystal layers ∼1.6 nm thick and two-dimensionally dispersed amorphous silicon oxide (a-SiO{sub x}) particles with sizes of ∼1 nm or less. The a-SiO{sub x} particles were enclosed with the Cr(Al)N layers. The coating had a low indentation hardness of ∼25 GPa at room temperature, due to a high oxide fraction of 38 vol. % and a low substrate rotational speed of 1 rpm. Faster rotation and lower oxide fraction would make a-SiO{sub x} particles smaller, resulting in the formation of Cr(Al)N crystal including the very fine a-SiO{sub x} particles with small number density. They would work as obstacles for the lattice deformation of the Cr(Al)N crystals. We have fabricated a superhard coating of Cr(Al)N/17 vol. % SiO{sub x} with a hardness of 46 GPa prepared at 12 rpm.

Conformal coating of amorphous silicon and germanium by high pressure chemical vapor deposition for photovoltaic fabrics

Science.gov (United States)

Ji, Xiaoyu; Cheng, Hiu Yan; Grede, Alex J.; Molina, Alex; Talreja, Disha; Mohney, Suzanne E.; Giebink, Noel C.; Badding, John V.; Gopalan, Venkatraman

2018-04-01

Conformally coating textured, high surface area substrates with high quality semiconductors is challenging. Here, we show that a high pressure chemical vapor deposition process can be employed to conformally coat the individual fibers of several types of flexible fabrics (cotton, carbon, steel) with electronically or optoelectronically active materials. The high pressure (˜30 MPa) significantly increases the deposition rate at low temperatures. As a result, it becomes possible to deposit technologically important hydrogenated amorphous silicon (a-Si:H) from silane by a simple and very practical pyrolysis process without the use of plasma, photochemical, hot-wire, or other forms of activation. By confining gas phase reactions in microscale reactors, we show that the formation of undesired particles is inhibited within the microscale spaces between the individual wires in the fabric structures. Such a conformal coating approach enables the direct fabrication of hydrogenated amorphous silicon-based Schottky junction devices on a stainless steel fabric functioning as a solar fabric.

Optimization of wear behavior of electroless Ni-P-W coating under dry and lubricated conditions using genetic algorithm (GA

Directory of Open Access Journals (Sweden)

Arkadeb Mukhopadhyay

2016-12-01

Full Text Available The present study aims to investigate the tribological behavior of Ni-P-W coating under dry and lubricated condition. The coating is deposited onto mild steel (AISI 1040 specimens by the electroless method using a sodium hypophosphite based alkaline bath. Coating characterization is done to investigate the effect of microstructure on its performance. The change in microhardness is observed to be quite significant after annealing the deposits at 400°C for 1h. A pin–on–disc type tribo-tester is used to investigate the tribological behavior of the coating under dry and lubricated conditions. The experimental design formulation is based on Taguchi’s orthogonal array. The design parameters considered are the applied normal load, sliding speed and sliding duration while the response parameter is wear depth. Multiple regression analysis is employed to obtain a quadratic model of the response variables with the main design parameters under considerations. A high value of coefficient of determination of 95.3% and 87.5% of wear depth is obtained under dry and lubricated conditions, respectively which indicate good correlation between experimental results and the multiple regression models. Analysis of variance at a confidence level of 95% shows that the models are statistically significant. Finally, the quadratic equations are used as objective functions to obtain the optimal combination of tribo testing parameters for minimum wear depth using genetic algorithm (GA.

Erosion behavior of W-Ta coatings in plasmas of stationary mirror penning discharges

International Nuclear Information System (INIS)

Belous, V.A.; Bondarenko, M.N.; Glazunov, G.P.; Ilchenko, A.V.; Kuprin, A.S.; Konotopskiy, A.L.; Lunyov, V.M.; Ovcharenko, V.D.

2016-01-01

Investigations had been carried out of the influence of Ta alloying (2...16 wt.%) in W-coatings on their erosion behavior in steady state plasmas of Penning discharges in different gases: argon, nitrogen, and hydrogen. The coatings were deposited on stainless steel substrates by argon ion sputtering of targets made from appropriate metals. For comparison the erosion behavior had been examined of pure W and Ta coatings obtained by the same method. It was shown the essential decrease of an erosion rate after Ta addition in W coatings. The possible physical mechanism is suggested to explain such erosion behavior

Tribological properties of amorphous hydrogenated (a-C:H) and hydrogen-free tetrahedral (ta-C) diamond-like carbon coatings under jatropha biodegradable lubricating oil at different temperatures

Science.gov (United States)

Mobarak, H. M.; Masjuki, H. H.; Mohamad, E. Niza; Kalam, M. A.; Rashedul, H. K.; Rashed, M. M.; Habibullah, M.

2014-10-01

The application of diamond-like carbon (DLC) coatings on automotive components is emerging as a favorable strategy to address the recent challenges in the industry. DLC coatings can effectively lower the coefficient of friction (CoF) and wear rate of engine components, thereby improving their fuel efficiency and durability. The lubrication of ferrous materials can be enhanced by a large amount of unsaturated and polar components of oils. Therefore, the interaction between nonferrous coatings (e.g., DLC) and vegetable oil should be investigated. A ball-on-plate tribotester was used to run the experiments. Stainless steel plates coated with amorphous hydrogenated (a-C:H) DLC and hydrogen-free tetrahedral (ta-C) DLC that slide against 440C stainless steel ball were used to create a ball-on-plate tribotester. The wear track was investigated through scanning electron microscopy. Energy dispersive and X-ray photoelectron spectroscopies were used to analyze the tribofilm inside the wear track. Raman analysis was performed to investigate the structural changes in the coatings. At high temperatures, the CoF in both coatings decreased. The wear rate, however, increased in the a-C:H but decreased in the ta-C DLC-coated plates. The CoF and the wear rate (coated layer and counter surface) were primarily influenced by the graphitization of the coating. Tribochemical films, such as polyphosphate glass, were formed in ta-C and acted as protective layers. Therefore, the wear rate of the ta-C DLC was lower than that of the-C:H DLC.

Fine Structure Study of the Plasma Coatings B4C-Ni-P

Science.gov (United States)

Kornienko, E. E.; Bezrukova, V. A.; Kuz'min, V. I.; Lozhkin, V. S.; Tutunkova, M. K.

2017-12-01

The article considers structure of coatings formed of the B4C-Ni-P powder. The coatings were deposited using air-plasma spraying with the unit for annular injection of powder. The pipes from steel 20 (0.2 % C) were used as a substrate. The structure and phase composition of the coatings were studied by optical microscopy, scanning electron microscopy, transmission electron microscopy and X-ray diffractometry. It is shown that high-density composite coatings consisting of boron carbide particles distributed in the nickel boride metal matrix are formed using air-plasma spraying. The areas with round inclusions characterized by the increased amount of nickel, phosphorus and boron are located around the boron carbide particles. Boron oxides and nickel oxides are also present in the coatings. Thin interlayers with amorphous-crystalline structure are formed around the boron carbide particles. The thickness of these interlayers does not exceed 1 μm. The metal matrix material represents areas with nanocrystalline structure and columnar crystals.

Morphological and microstructural characterization of nanostructured pure α-phase W coatings on a wide thickness range

Energy Technology Data Exchange (ETDEWEB)

Gordillo, N., E-mail: nuri.gordillo@gmail.com [Instituto de Fusión Nuclear, ETSI de Industriales, Universidad Politécnica de Madrid, C/José Gutierrez Abascal, 2, E-28006 Madrid (Spain); CEI Campus Moncloa, UCM-UPM, Madrid (Spain); Panizo-Laiz, M. [Instituto de Fusión Nuclear, ETSI de Industriales, Universidad Politécnica de Madrid, C/José Gutierrez Abascal, 2, E-28006 Madrid (Spain); Tejado, E. [Department of Materials Science, Research Centre on Safety and Durability of Structures and Materials (CISDEM), UPM-CSIC, C/Profesor Aranguren s/n, E-28040 Madrid (Spain); Centro Nacional de Investigaciones Metalúrgicas, CENIM-CSIC, Madrid (Spain); Fernandez-Martinez, I. [Instituto de Energía Solar (IES), Universidad Politécnica de Madrid, Avenida Complutense s/n, E-28040 Madrid (Spain); Instituto de Microelectrónica de Madrid, IMM-CNM-CSIC, Isaac Newton 8 PTM, Tres Cantos, E-28760 Madrid (Spain); Rivera, A. [Instituto de Fusión Nuclear, ETSI de Industriales, Universidad Politécnica de Madrid, C/José Gutierrez Abascal, 2, E-28006 Madrid (Spain); Pastor, J.Y. [Department of Materials Science, Research Centre on Safety and Durability of Structures and Materials (CISDEM), UPM-CSIC, C/Profesor Aranguren s/n, E-28040 Madrid (Spain); Castro, C. Gómez de [Departamento de Física de Materiales, Facultad de CC. Químicas, Universidad Complutense de Madrid, Ciudad Universitaria s/n, E-28040 Madrid (Spain); and others

2014-10-15

Highlights: • Pure α-phase tungsten nanostructures were deposited by DC-magnetron sputtering. • Non-delaminated coatings were achieved at powers ≤50 W. • The coating thicknesses vary from 30 nm up to ∼4.0 μm. • The influence of the substrate on the coating properties was investigated. • We report on the morphological, microstructural and mechanical properties. - Abstract: Nanostructured tungsten (nanoW) coatings have been deposited by DC magnetron sputtering. First, the influence of the sputtering power on the adhesion of the coatings to the substrate was investigated by depositing coatings at powers varying from 30 up to 220 W. Non-delaminated coatings were achieved at powers ≤50 W. Second, the influence of coating thickness on the morphological, microstructural and mechanical properties was investigated for films deposited at 50 W with thicknesses varying from 30 nm up to ∼4.0 μm. SEM images reveal that all the films are highly compact, consisting of nanometer sized columns that grow perpendicular to the substrate. XRD data evidence that films are monophasic, being made of pure α-phase. All coatings show compressive stress and low micro-strain. Nanoindentation tests show that coatings have a hardness higher than that reported for coarse grained W. No significant dependence of the previous properties on coating thickness was observed. Finally, the influence of the substrate on coatings properties was studied, by depositing a W coating at a power of 50 W on a commercial steel substrate: no significant dependence was found.

Physical and Microstructure Properties of MgAl2C2 Matrix Composite Coating on Titanium

Science.gov (United States)

Li, Peng

2014-12-01

This work is based on the dry sliding wear of the MgAl2C2-TiB2-FeSi composite coating deposited on a pure Ti using a laser cladding technique. Scanning electron microscope images indicate that the nanocrystals and amorphous phases are produced in such coating. X-ray diffraction result indicated that such coating mainly consists of MgAl2C2, Ti-B, Ti-Si, Fe-Al, Ti3SiC2, TiC and amorphous phases. The high resolution transmission electron microscope image indicated that the TiB nanorods were produced in the coating, which were surrounded by other fine precipitates, favoring the formation of a fine microstructure. With increase of the laser power from 0.85 kW to 1.00 kW, the micro-hardness decreased from 1350 1450 HV0.2 to 1200 1300 HV0.2. The wear volume loss of the laser clad coating was 1/7 of pure Ti.

Bone tissue engineering on amorphous carbonated apatite and crystalline octacalcium phosphate-coated titanium discs

NARCIS (Netherlands)

Dekker, Robert J.; de Bruijn, Joost Dick; Stigter, Martin; Barrère, F.; Layrolle, Pierre; van Blitterswijk, Clemens

2005-01-01

Poor fixation of bone replacement implants, e.g. the artificial hip, in implantation sites with inferior bone quality and quantity may be overcome by the use of implants coated with a cultured living bone equivalent. In this study, we tested, respectively, amorphous carbonated apatite (CA)- and

Multivariate Quantification of the Solid State Phase Composition of Co-Amorphous Naproxen-Indomethacin

DEFF Research Database (Denmark)

Beyer, Andreas; Grohganz, Holger; Löbmann, Korbinian

2015-01-01

To benefit from the optimized dissolution properties of active pharmaceutical ingredients in their amorphous forms, co-amorphisation as a viable tool to stabilize these amorphous phases is of both academic and industrial interest. Reports dealing with the physical stability and recrystallization...... components was prepared and analyzed by XRPD. In order to test the model performances, leave-one-out cross validation was performed and revealed root mean square errors of validation between 3.11% and 3.45% for the crystalline molar fractions and 5.57% for the co-amorphous molar fraction. In summary, even...

pH and redox responsive polymer for antifouling surface coating

International Nuclear Information System (INIS)

Lee, Kang Seok; In, Insik; Park, Sung Young

2014-01-01

Graphical abstract: Dual responsive surface with highly fouling resistance with the formation of a pH-dependent benzoic imine and redox-sensitive disulfide bond has been developed using a catechol/benzoic acid conjugated polymer and disulfide containing amine end-capped Pluronic. - Highlights: • Stimuli-responsive antifouling surface was prepared by layer-by-layer method. • The surface contact angle showed responsive behavior via pH and redox environments. • Simply coated polymer completely prevented cell adhesion onto surfaces. - Abstract: A dual environmentally responsive polymer with a highly fouling-resistant surface has been developed using poly[(hydroxyethyl methacrylate-g-benzoic acid)-co-(dimethylaminoethyl methacrylate-g-2-chloro-3′, 4′-dihydroxyacetophenone)] [poly[(HEMA-BA)-co-(DMAEMA-CCDP)], P1] as a coating material. The redox-sensitive disulfide containing amine end-capped Pluronic [(Plu-S-S-NH 2 ), P2] was then introduced over the P1 surface via the formation of a pH-dependent benzoic imine bond, where the polyethylene glycol (PEG) acts as an antifouling agent. The successful adhesion of P1 and the deposition of P2 onto the P1-coated substrate were ascertained with X-ray photoelectron spectroscopy (XPS). In vitro cell adhesion followed by scanning electron microscopy (SEM) indicated an excellent antifouling nature of the P2 layer. Consequently, the reattachment of Hela cells was strongly observed when P2 layered on P1-coated substrates (P1–P2) was pretreated at lower pH and high redox conditions. The P1–P2 bilayer-coated substrate has exhibited a great advantage in its effective antifouling behaviors with well-tuned cell attachment and detachment

pH and redox responsive polymer for antifouling surface coating

Energy Technology Data Exchange (ETDEWEB)

Lee, Kang Seok [Department of Chemical and Biological Engineering, Korea National University of Transportation, Chungju, 380-702 (Korea, Republic of); In, Insik, E-mail: in1@ut.ac.kr [Department of Polymer Science and Engineering, Korea National University of Transportation, Chungju, 380-702 (Korea, Republic of); Department of IT Convergence, Korea National University of Transportation, Chungju, 380-702 (Korea, Republic of); Park, Sung Young, E-mail: parkchem@ut.ac.kr [Department of Chemical and Biological Engineering, Korea National University of Transportation, Chungju, 380-702 (Korea, Republic of); Department of IT Convergence, Korea National University of Transportation, Chungju, 380-702 (Korea, Republic of)

2014-09-15

Graphical abstract: Dual responsive surface with highly fouling resistance with the formation of a pH-dependent benzoic imine and redox-sensitive disulfide bond has been developed using a catechol/benzoic acid conjugated polymer and disulfide containing amine end-capped Pluronic. - Highlights: • Stimuli-responsive antifouling surface was prepared by layer-by-layer method. • The surface contact angle showed responsive behavior via pH and redox environments. • Simply coated polymer completely prevented cell adhesion onto surfaces. - Abstract: A dual environmentally responsive polymer with a highly fouling-resistant surface has been developed using poly[(hydroxyethyl methacrylate-g-benzoic acid)-co-(dimethylaminoethyl methacrylate-g-2-chloro-3′, 4′-dihydroxyacetophenone)] [poly[(HEMA-BA)-co-(DMAEMA-CCDP)], P1] as a coating material. The redox-sensitive disulfide containing amine end-capped Pluronic [(Plu-S-S-NH{sub 2}), P2] was then introduced over the P1 surface via the formation of a pH-dependent benzoic imine bond, where the polyethylene glycol (PEG) acts as an antifouling agent. The successful adhesion of P1 and the deposition of P2 onto the P1-coated substrate were ascertained with X-ray photoelectron spectroscopy (XPS). In vitro cell adhesion followed by scanning electron microscopy (SEM) indicated an excellent antifouling nature of the P2 layer. Consequently, the reattachment of Hela cells was strongly observed when P2 layered on P1-coated substrates (P1–P2) was pretreated at lower pH and high redox conditions. The P1–P2 bilayer-coated substrate has exhibited a great advantage in its effective antifouling behaviors with well-tuned cell attachment and detachment.

Evaluation of coat uniformity and taste-masking efficiency of irregular-shaped drug particles coated in a modified tangential spray fluidized bed processor.

Science.gov (United States)

Xu, Min; Heng, Paul Wan Sia; Liew, Celine Valeria

2015-01-01

To explore the feasibility of coating irregular-shaped drug particles in a modified tangential spray fluidized bed processor (FS processor) and evaluate the coated particles for their coat uniformity and taste-masking efficiency. Paracetamol particles were coated to 20%, w/w weight gain using a taste-masking polymer insoluble in neutral and basic pH but soluble in acidic pH. In-process samples (5, 10 and 15%, w/w coat) and the resultant coated particles (20%, w/w coat) were collected to monitor the changes in their physicochemical attributes. After coating to 20%, w/w coat weight gain, the usable yield was 81% with minimal agglomeration (coat compared with the uncoated particles. A 15%, w/w coat was optimal for inhibiting drug release in salivary pH with subsequent fast dissolution in simulated gastric pH. The FS processor shows promise for direct coating of irregular-shaped drug particles with wide size distribution. The coated particles with 15% coat were sufficiently taste masked and could be useful for further application in orally disintegrating tablet platforms.

Tribological properties, corrosion resistance and biocompatibility of magnetron sputtered titanium-amorphous carbon coatings

Science.gov (United States)

Dhandapani, Vishnu Shankar; Subbiah, Ramesh; Thangavel, Elangovan; Arumugam, Madhankumar; Park, Kwideok; Gasem, Zuhair M.; Veeraragavan, Veeravazhuthi; Kim, Dae-Eun

2016-05-01

Amorphous carbon incorporated with titanium (a-C:Ti) was coated on 316L stainless steel (SS) by magnetron sputtering technique to attain superior tribological properties, corrosion resistance and biocompatibility. The morphology, topography and functional groups of the nanostructured a-C:Ti coatings in various concentrations were analyzed using atomic force microscopy (AFM), Raman, X-Ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). Raman and XPS analyses confirmed the increase in sp2 bonds with increasing titanium content in the a-C matrix. TEM analysis confirmed the composite nature of the coating and the presence of nanostructured TiC for Ti content of 2.33 at.%. This coating showed superior tribological properties compared to the other a-C:Ti coatings. Furthermore, electrochemical corrosion studies were performed against stimulated body fluid medium in which all the a-C:Ti coatings showed improved corrosion resistance than the pure a-C coating. Preosteoblasts proliferation and viability on the specimens were tested and the results showed that a-C:Ti coatings with relatively high Ti (3.77 at.%) content had better biocompatibility. Based on the results of this work, highly durable coatings with good biocompatibility could be achieved by incorporation of optimum amount of Ti in a-C coatings deposited on SS by magnetron sputtering technique.

The Effects of Particle Size on the Surface Properties of an HVOF Coating of WC-Co

Energy Technology Data Exchange (ETDEWEB)

Cho, Tong Yul; Yoon, Jae Hong; Yoon, Sang Hwan; Joo, Yun Kon [Changwon National University, Changwon (Korea, Republic of); Choi, Won Ho; Son, Young Bok [Xinix Metallizing Co., Ltd, Gyungnam (Korea, Republic of)

2017-04-15

The effects of particle size on the surface properties of HVOF spray coating were studied to improve of the durability of metal components. Micro and nano sized WC-12Co powders were coated on the surface of Inconel718, and the effects of particle size on surface properties were studied. Surface hardness was reduced when the particle sizes of the powder were decreased, because the larger specific surface area of the smaller particles caused greater heat absorption and decomposition of the hard WC to less hard W{sub 2}C and graphite. Porosity was increased by decreasing the particle size, because the larger specific surface area of the smaller particles caused a greater decomposition of WC to W{sub 2}C and free carbon. The free carbon formed carbon oxide gases which created the porous surface. The friction coefficient was reduced by decreasing the particle size because the larger specific surface area of the smaller particles produced more free carbon free Co and Co oxide which acted as solid lubricants. The friction coefficient increased when the surface temperature was increased from 25 to 500 ℃, due to local cold welding. To improve the durability of metal mechanical components, WC-Co coating with the proper particle size is recommended.

Amorphous Al–Mn coating on NdFeB magnets: Electrodeposition from AlCl3–EMIC–MnCl2 ionic liquid and its corrosion behavior

International Nuclear Information System (INIS)

Chen Jing; Xu Bajin; Ling Guoping

2012-01-01

Amorphous Al–Mn coating was electrodeposited on NdFeB magnets from AlCl 3 –EMIC–MnCl 2 ionic liquid with the pretreatment of anodic electrolytic etching in AlCl 3 –EMIC ionic liquid at room temperature. The microstructure, composition and phase constituents of the coatings were investigated by scanning electron microscopy (SEM), energy-dispersive X-ray spectrometry (EDS), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The corrosion resistance of the coatings was tested by means of potentiodynamic polarization and immersion test in 3.5 wt. % NaCl solution. The results show that anodic electrolytic etching in AlCl 3 –EMIC ionic liquid is a satisfactory pretreatment to remove the surface oxide film and favor the adhesion of the Al–Mn alloy coating to the NdFeB substrate. The amorphous Al–Mn alloy coating provides sacrificial anodic protection for NdFeB. It exhibited good corrosion resistance and significantly reduced the corrosion current density of NdFeB by three orders of magnitude at potentiodynamic polarization. - Highlights: ► Amorphous Al–Mn alloy coating was electrodeposited on NdFeB magnet from ionic liquid. ► To remove the surface oxides of NdFeB, anodic etching pretreatment is used. ► The deposited Al–Mn alloy coating shows high adhesion to the NdFeB substrate. ► Corrosion tests show that amorphous Al–Mn alloy coating is anodic coating for NdFeB magnet.

INFLUENCE OF THE COOLING RATE AND THE BLEND RATIO ON THE PHYSICAL STABILTIY OF CO-AMORPHOUS NAPROXEN/INDOMETHACIN

DEFF Research Database (Denmark)

Beyer, Andreas; Grohganz, Holger; Löbmann, Korbinian

2016-01-01

Co-amorphisation represents a promising approach to increase the physical stability and dissolution rate of amorphous active pharmaceutical ingredients (APIs) as an alternative to polymer glass solutions. For amorphous and co-amorphous systems, it is reported that the preparation method and the b......Co-amorphisation represents a promising approach to increase the physical stability and dissolution rate of amorphous active pharmaceutical ingredients (APIs) as an alternative to polymer glass solutions. For amorphous and co-amorphous systems, it is reported that the preparation method...... and the blend ratio play major roles with regard to the resulting physical stability. Therefore, in the present study, co-amorphous naproxen-indomethacin (NAP/IND) was prepared by melt-quenching at three different cooling rates and at ten different NAP/IND blend ratios. The samples were analyzed using XRPD...... and FTIR, both directly after preparation and during storage to investigate their physical stabilities. All cooling methods led to fully amorphous samples, but with significantly different physical stabilities. Samples prepared by fast cooling had a higher degree of crystallinity after 300 d of storage...

High throughput deposition of hydrogenated amorphous carbon coatings on rubber with expanding thermal plasma

NARCIS (Netherlands)

Pei, Y.T.; Eivani, A.R.; Zaharia, T.; Kazantis, A.V.; Sanden, van de M.C.M.; De Hosson, J.T.M.

2014-01-01

Flexible hydrogenated amorphous carbon (a-C:H) thin film coated on rubbers has shown outstanding protection of rubber seals from friction and wear. This work concentrates on the potential advances of expanding thermal plasma (ETP) process for a high throughput deposition of a-C:H thin films in

Synthesis and electrochemical performances of amorphous carbon-coated Sn Sb particles as anode material for lithium-ion batteries

Science.gov (United States)

Wang, Zhong; Tian, Wenhuai; Liu, Xiaohe; Yang, Rong; Li, Xingguo

2007-12-01

The amorphous carbon coating on the Sn-Sb particles was prepared from aqueous glucose solutions using a hydrothermal method. Because the outer layer carbon of composite materials is loose cotton-like and porous-like, it can accommodate the expansion and contraction of active materials to maintain the stability of the structure, and hinder effectively the aggregation of nano-sized alloy particles. The as-prepared composite materials show much improved electrochemical performances as anode materials for lithium-ion batteries compared with Sn-Sb alloy and carbon alone. This amorphous carbon-coated Sn-Sb particle is extremely promising anode materials for lithium secondary batteries and has a high potentiality in the future use.

Characterization of microstructure and surface properties of hybrid coatings of WC-CoCr prepared by laser heat treatment and high velocity oxygen fuel spraying

International Nuclear Information System (INIS)

Zhang Shihong; Cho, Tong-Yul; Yoon, Jae-Hong; Fang, Wei; Song, Ki-O; Li Mingxi; Joo, Yun-Kon; Lee, Chan Gyu

2008-01-01

The microstructure and microhardness of high velocity oxygen fuel-sprayed WC-CoCr coatings were comparatively studied both before and after laser heat treatment of the coatings. Optical microscopy, scanning electron microscopy, X-ray diffraction and microhardness testing were applied to investigate the microstructure, phase composition, porosity and microhardness. The results indicate that WC is still present, and W 2 C has appeared, while neither cobalt nor σ-CrCo is detectable. Co 4 W 2 C has appeared in the high velocity oxygen fuel-sprayed coating after laser heat treatment as compared to the coating before laser treatment. The relative content of the W 2 C has not increased with laser treatment, but the laser treatment has essentially eliminated the porosity almost entirely, providing a more homogeneous and densified microstructure. The laser heat treatment has effected the formation of a denser compact coating on the substrate. After laser heat treatment, the thickness of the coating has decreased from 300 μm to 225 μm. This corresponds to an average porosity in the high velocity oxygen fuel-sprayed coating that is approximately five times greater than that in the subsequently laser heat-treated coating. The laser treatment has also resulted in an increased hardness of the coating near the surface, where the average value increased from Hv 0.2 = 1262.4 in the coating before laser heat treatment to Hv 0.2 = 1818.7 after laser heat treatment

Compositions of corrosion-resistant Fe-based amorphous metals suitable for producing thermal spray coatings

Science.gov (United States)

Farmer, Joseph C; Wong, Frank M.G.; Haslam, Jeffery J; Ji, Xiaoyan; Day, Sumner D; Blue, Craig A; Rivard, John D.K.; Aprigliano, Louis F; Kohler, Leslie K; Bayles, Robert; Lemieux, Edward J; Yang, Nancy; Perepezko, John H; Kaufman, Larry; Heuer, Arthur; Lavernia, Enrique J

2013-09-03

A method of coating a surface comprising providing a source of amorphous metal that contains manganese (1 to 3 atomic %), yttrium (0.1 to 10 atomic %), and silicon (0.3 to 3.1 atomic %) in the range of composition given in parentheses; and that contains the following elements in the specified range of composition given in parentheses: chromium (15 to 20 atomic %), molybdenum (2 to 15 atomic %), tungsten (1 to 3 atomic %), boron (5 to 16 atomic %), carbon (3 to 16 atomic %), and the balance iron; and applying said amorphous metal to the surface by a spray.

Tribological properties of amorphous hydrogenated (a-C:H) and hydrogen-free tetrahedral (ta-C) diamond-like carbon coatings under jatropha biodegradable lubricating oil at different temperatures

International Nuclear Information System (INIS)

Mobarak, H.M.; Masjuki, H.H.; Mohamad, E. Niza; Kalam, M.A.; Rashedul, H.K.; Rashed, M.M.; Habibullah, M.

2014-01-01

Highlights: • We tested a-C:H and ta-C DLC coatings as a function of temperature. • Jatropha oil contains large amounts of polar components that enhanced the lubricity of coatings. • CoF decreases with increasing temperature for both contacts. • Wear rate increases with increasing temperature in a-C:H and decreases in ta-C DLC. • At high temperature, ta-C coatings confer more protection than a-C:H coatings. - Abstract: The application of diamond-like carbon (DLC) coatings on automotive components is emerging as a favorable strategy to address the recent challenges in the industry. DLC coatings can effectively lower the coefficient of friction (CoF) and wear rate of engine components, thereby improving their fuel efficiency and durability. The lubrication of ferrous materials can be enhanced by a large amount of unsaturated and polar components of oils. Therefore, the interaction between nonferrous coatings (e.g., DLC) and vegetable oil should be investigated. A ball-on-plate tribotester was used to run the experiments. Stainless steel plates coated with amorphous hydrogenated (a-C:H) DLC and hydrogen-free tetrahedral (ta-C) DLC that slide against 440C stainless steel ball were used to create a ball-on-plate tribotester. The wear track was investigated through scanning electron microscopy. Energy dispersive and X-ray photoelectron spectroscopies were used to analyze the tribofilm inside the wear track. Raman analysis was performed to investigate the structural changes in the coatings. At high temperatures, the CoF in both coatings decreased. The wear rate, however, increased in the a-C:H but decreased in the ta-C DLC-coated plates. The CoF and the wear rate (coated layer and counter surface) were primarily influenced by the graphitization of the coating. Tribochemical films, such as polyphosphate glass, were formed in ta-C and acted as protective layers. Therefore, the wear rate of the ta-C DLC was lower than that of the-C:H DLC

Tribological properties of amorphous hydrogenated (a-C:H) and hydrogen-free tetrahedral (ta-C) diamond-like carbon coatings under jatropha biodegradable lubricating oil at different temperatures

Energy Technology Data Exchange (ETDEWEB)

Mobarak, H.M., E-mail: mobarak.ho31@yahoo.com; Masjuki, H.H.; Mohamad, E. Niza, E-mail: edzrol@um.edu.my; Kalam, M.A.; Rashedul, H.K.; Rashed, M.M.; Habibullah, M.

2014-10-30

Highlights: • We tested a-C:H and ta-C DLC coatings as a function of temperature. • Jatropha oil contains large amounts of polar components that enhanced the lubricity of coatings. • CoF decreases with increasing temperature for both contacts. • Wear rate increases with increasing temperature in a-C:H and decreases in ta-C DLC. • At high temperature, ta-C coatings confer more protection than a-C:H coatings. - Abstract: The application of diamond-like carbon (DLC) coatings on automotive components is emerging as a favorable strategy to address the recent challenges in the industry. DLC coatings can effectively lower the coefficient of friction (CoF) and wear rate of engine components, thereby improving their fuel efficiency and durability. The lubrication of ferrous materials can be enhanced by a large amount of unsaturated and polar components of oils. Therefore, the interaction between nonferrous coatings (e.g., DLC) and vegetable oil should be investigated. A ball-on-plate tribotester was used to run the experiments. Stainless steel plates coated with amorphous hydrogenated (a-C:H) DLC and hydrogen-free tetrahedral (ta-C) DLC that slide against 440C stainless steel ball were used to create a ball-on-plate tribotester. The wear track was investigated through scanning electron microscopy. Energy dispersive and X-ray photoelectron spectroscopies were used to analyze the tribofilm inside the wear track. Raman analysis was performed to investigate the structural changes in the coatings. At high temperatures, the CoF in both coatings decreased. The wear rate, however, increased in the a-C:H but decreased in the ta-C DLC-coated plates. The CoF and the wear rate (coated layer and counter surface) were primarily influenced by the graphitization of the coating. Tribochemical films, such as polyphosphate glass, were formed in ta-C and acted as protective layers. Therefore, the wear rate of the ta-C DLC was lower than that of the-C:H DLC.

Thermal stability of amorphous structure and magnetic properties Fe{sub 80-x}Co{sub x}P{sub 14}B {sub 6} (x=20-40) ribbons

Energy Technology Data Exchange (ETDEWEB)

Kostyrya, S.A.; Idzikowski, B. [Institute of Molecular Physics, Polish Academy of Sciences, M. Smoluchowskiego 17, 60-179 Poznan (Poland); Tkatch, V.I.; Popov, V.V.; Rassolov, S.G. [Donetsk Physics and Engineering Institute of National Academy of Sciences of Ukraine, R. Luxemburg 72, 83114 Donetsk (Ukraine)

2006-01-01

Amorphous structure and its thermal stability as well as magnetic properties of Fe{sub 80-x}Co{sub x}P{sub 14}B{sub 6} (20{<=}x{<=}40) glasses have been studied by X-ray diffraction, non-isothermal differential scanning calorimetry (DSC) and thermomagnetic (TMG) measurements. The Curie temperature increases with Co content, while the glass transition and crystallization onset temperatures decrease. As a result, for alloys x=30, 32 and 35 at%, the transition into paramagnetic state take place close to glass transition temperature. However, for x=40 at% the TMG curve, in the vicinity of magnetic transition temperature, is overlapped by ferromagnetic crystallization products. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Hot Melt Extrusion and Spray Drying of Co-amorphous Indomethacin-Arginine With Polymers.

Science.gov (United States)

Lenz, Elisabeth; Löbmann, Korbinian; Rades, Thomas; Knop, Klaus; Kleinebudde, Peter

2017-01-01

Co-amorphous drug-amino acid systems have gained growing interest as an alternative to common amorphous formulations which contain polymers as stabilizers. Several preparation methods have recently been investigated, including vibrational ball milling on a laboratory scale or spray drying in a larger scale. In this study, the feasibility of hot melt extrusion for continuous manufacturing of co-amorphous drug-amino acid formulations was examined, challenging the fact that amino acids melt with degradation at high temperatures. Furthermore, the need for an addition of a polymer in this process was evaluated. After a polymer screening via the solvent evaporation method, co-amorphous indomethacin-arginine was prepared by a melting-solvent extrusion process without and with copovidone. The obtained products were characterized with respect to their solid-state properties, non-sink dissolution behavior, and stability. Results were compared to those of spray-dried formulations with the same compositions and to spray-dried indomethacin-copovidone. Overall, stable co-amorphous systems could be prepared by extrusion without or with copovidone, which exhibited comparable molecular interaction properties to the respective spray-dried products, while phase separation was detected by differential scanning calorimetry in several cases. The formulations containing indomethacin in combination with arginine and copovidone showed enhanced dissolution behavior over the formulations with only copovidone or arginine. Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

The influence of co-formers on the dissolution rates of co-amorphous sulfamerazine/excipient systems

DEFF Research Database (Denmark)

Gniado, Katarzyna; Löbmann, Korbinian; Rades, Thomas

2016-01-01

A comprehensive study on the dissolution properties of three co-amorphous sulfamerazine/excipient systems, namely sulfamerazine/deoxycholic acid, sulfamerazine/citric acid and sulfamerazine/sodium taurocholate (SMZ/DA, SMZ/CA and SMZ/NaTC; 1:1 molar ratio), is reported. While all three co...

Development of a screening method for co-amorphous formulations of drugs and amino acids

DEFF Research Database (Denmark)

Kasten, Georgia; Grohganz, Holger; Rades, Thomas

2016-01-01

Using amino acids (AA) as low molecular weight excipients in the preparation of co-amorphous blends with the aim to stabilize the drug in the amorphous form have been discussed in a range of studies. However, there is currently no theoretical consensus behind which AA would be a suitable co...

Friction and wear behaviour of Mo-W doped carbon-based coating during boundary lubricated sliding

Science.gov (United States)

Hovsepian, Papken Eh.; Mandal, Paranjayee; Ehiasarian, Arutiun P.; Sáfrán, G.; Tietema, R.; Doerwald, D.

2016-03-01

A molybdenum and tungsten doped carbon-based coating (Mo-W-C) was developed in order to provide low friction in boundary lubricated sliding condition at ambient and at high temperature. The Mo-W-C coating showed the lowest friction coefficient among a number of commercially available state-of-the-art DLC coatings at ambient temperature. At elevated temperature (200 °C), Mo-W-C coating showed a significant reduction in friction coefficient with sliding distance in contrast to DLC coatings. Raman spectroscopy revealed the importance of combined Mo and W doping for achieving low friction at both ambient and high temperature. The significant decrease in friction and wear rate was attributed to the presence of graphitic carbon debris (from coating) and 'in situ' formed metal sulphides (WS2 and MoS2, where metals were supplied from coating and sulphur from engine oil) in the transfer layer.

Amorphization within the tablet

DEFF Research Database (Denmark)

Doreth, Maria; Hussein, Murtadha Abdul; Priemel, Petra A.

2017-01-01

, the feasibility of microwave irradiation to prepare amorphous solid dispersions (glass solutions) in situ was investigated. Indomethacin (IND) and polyvinylpyrrolidone K12 (PVP) were tableted at a 1:2 (w/w) ratio. In order to study the influence of moisture content and energy input on the degree of amorphization......, tablet formulations were stored at different relative humidity (32, 43 and 54% RH) and subsequently microwaved using nine different power-time combinations up to a maximum energy input of 90 kJ. XRPD results showed that up to 80% (w/w) of IND could be amorphized within the tablet. mDSC measurements...

New generation of plasma-sprayed mullite coatings on silicon carbide

Science.gov (United States)

Lee, Kang N.; Miller, Robert A.; Jacobson, Nathan S.

1995-01-01

Mullite is promising as a protective coating for silicon-based ceramics in aggressive high-temperature environments. Conventionally plasma-sprayed mullite on SiC tends to crack and debond on thermal cycling. It is shown that this behavior is due to the presence of amorphous mullite in the conventionally sprayed mullite. Heating the SiC substrate during the plasma spraying eliminated the amorphous phase and produced coatings with dramatically improved properties. The new coating exhibits excellent adherence and crack resistance under thermal cycling between room temperature and 1000 to 1400 C. Preliminary tests showed good resistance to Na2CO3-induced hot corrosion.

Random anisotropy studies in amorphous Co-Tb ribbons

International Nuclear Information System (INIS)

Hassanain, N.; Berrada, A.; Lassri, H.; Krishnan, R.

1995-01-01

Amorphous Co 1-x Tb x ribbons with x=0.45, 0.55 and 0.65 have been prepared by melt spinning technique. Magnetization measurements were carried out at 4.2 K, under magnetic fields up to 150 kOe. The Co moment is found to be very small and the Tb moment is 7.15μ B at 4.2 K, which indicates a speromagnetic spin structure. Using Chudnovsky's theory we have extracted some fundamental magnetic parameters. ((orig.))

Structure adhesion and corrosion resistance study of tungsten bisulfide doped with titanium deposited by DC magnetron co-sputtering

Energy Technology Data Exchange (ETDEWEB)

De La Roche, J. [Laboratorio de Física del Plasma, Universidad Nacional de Colombia Sede Manizales, Km. 9 vía al aeropuerto, Campus La Nubia, Manizales (Colombia); González, J.M. [Laboratorio de Recubrimientos Duros y Aplicaciones Industriales – RDAI, Universidad del Valle, Calle 13 N° 100-00 Ciudadela Meléndez, Cali (Colombia); Restrepo-Parra, E., E-mail: erestrepop@unal.edu.co [Laboratorio de Física del Plasma, Universidad Nacional de Colombia Sede Manizales, Km. 9 vía al aeropuerto, Campus La Nubia, Manizales (Colombia); Sequeda, F. [Laboratorio de Recubrimientos Duros y Aplicaciones Industriales – RDAI, Universidad del Valle, Calle 13 N° 100-00 Ciudadela Meléndez, Cali (Colombia); Alleh, V.; Scharf, T.W. [The University of North Texas, Department of Materials Science and Engineering, Denton, TX 76203 (United States)

2014-11-30

Highlights: • Ti-doped WS{sub 2} films were grown via the magnetron co-sputtering technique. • At a high Ti percentage, the crystalline structure of WS{sub 2} coatings tends to be amorphous. • As the Ti percentage increases in WS{sub 2} coatings, nanocomposites tend to form. • Ti-doped WS{sub 2} films have elastic behavior compared with the plastic response of pure WS{sub 2} films. • A high Ti percentage increases the corrosion resistance of WS{sub 2} films. - Abstract: Titanium-doped tungsten bisulfide thin films (WS{sub 2}-Ti) were grown using a DC magnetron co-sputtering technique on AISI 304 stainless steel and silicon substrates. The films were produced by varying the Ti cathode power from 0 to 25 W. Using energy dispersive spectroscopy (EDS), the concentration of Ti in the WS{sub 2} was determined, and a maximum of 10% was obtained for the sample grown at 25 W. Moreover, the S/W ratio was calculated and determined to increase as a function of the Ti cathode power. According to transmission electron microscopy (TEM) results, at high titanium concentrations (greater than 6%), nanocomposite formation was observed, with nanocrystals of Ti embedded in an amorphous matrix of WS{sub 2}. Using the scratch test, the coatings’ adhesion was analyzed, and it was observed that as the Ti percentage was increased, the critical load (Lc) also increased. Furthermore, the failure type changed from plastic to elastic. Finally, the corrosion resistance was evaluated using the electrochemical impedance spectroscopy (EIS) technique, and it was observed that at high Ti concentrations, the corrosion resistance was improved, as Ti facilitates coating densification and generates a protective layer.

Influence of surface modified nanoilmenite/amorphous silica composite particles on the thermal stability of cold galvanizing coating

Directory of Open Access Journals (Sweden)

A.M. Al-Sabagh

2018-03-01

Full Text Available The present approach investigates the use of novel nanoilmenite/amorphous silica composite (NI/AS particles fabricated from ilmenite nanoparticles (FeTiO3 NPs and synthesized amorphous silica grains to improve thermal stability of the cold galvanizing coating. Transmission electron microscopic (TEM images demonstrated that both nanoilmenite and nanocomposite particles were of flaky-like nature and the average diameter of the particles is 20 nm. The lamellar shape of the nanocomposite and spherical nature of Zn-dust particles were illustrated by scanning electron microscopy (SEM micrographs. Different alkyd-based cold galvanizing coating formulations were modified using uniformly dispersing various amounts of the processed nanocomposite particles as a modifier to form some engineering nanocomposite coatings. Thermal stability of the nanocomposite and Zn-dust particles was determined by thermo-gravimetric analysis (TGA. From the obtained results it could be observed that the weight loss (% as a feature of the thermal stability in case of the nanocomposite particles was 2.9 compared to 85.9 for Zn-dust powder grains. Derivative thermo-gravimetric (DTG measurements were done under nitrogen atmosphere for the cured cold galvanizing coating samples heated from room temperature to 1000 °C. The obtained results revealed that the maximum decomposition temperature point in the third degradation step for 6% nanocomposite surface modified cured sample (CG-F was detected at 693 °C and was less value for unmodified conventional cold galvanizing coating (CG-A at 612 °C. The increase in thermal stability with increasing the concentration of nanocomposite particles could be mainly attributed to the interface surface interaction between the nanocomposite particles and alkyd resin matrix in which enhancing the inorganic-organic network stiffness by causing a reduction in the total free spaces and enhancement in the cross-linking density of the cured film

CO2 laser coating of nanodiamond on aluminum using an annular beam

International Nuclear Information System (INIS)

Blum, Rodger; Molian, Pal

2014-01-01

Laser coating of nanodiamond (ND) on aluminum alloy A319 substrate was investigated using a diffraction-free ring beam. A 1000 W continuous wave CO 2 laser in the ring beam configuration heated the 25–35 μm thick electrostatically sprayed ND powder layers on aluminum surface, melted a very thin layer (10 μm) of aluminum in a controlled fashion and caused phase transition of ND to form 50–60 μm thick ND/diamond-like carbon (DLC) coating. Significant improvements in friction, wear resistance and surface finish were observed in the ring beam method over the traditional Gaussian beam method suggesting that these thick (50–60 μm) ND/DLC laser coatings can outperform the currently used thin (<4 μm) chemically vapor deposited DLC coatings for aluminum parts in automobiles.

Moessbauer spectra studied of spin-wave excitation for amorphous alloys

International Nuclear Information System (INIS)

Huang Zhigao

1992-01-01

The average hyperfine fields of amorphous Fe 70 Co 20 Zr 10 , Fe 80 Co 10 Zr 10 and Fe 86 Co 4 -Zr 10 alloys at different temperature were measured by the Moessbauer technique. According to Bloch's T 3/2 relation, spin-wave excitations of above amorphous alloys were studied and their B 3/2 values were found to be 0.40 +- 0.02, 0.45 +- 0.02 and 0.88 +- 0.04, respectively. Comparing the B 3/2 values of crystals, a-Fe-(Co, Ni)-ME, a-Fe-(Cr, Mn, W)-ME and a-Fe-B or TM-Zr invar alloys, the obvious difference among them was observed. Above results can be explained well by the exchange coupling fluctuation and the disorder of spatial arrangement. In this work, the difference between the stiffness coefficients obtained from the inelastic neutron scattering and the magnetization measurements for amorphous Invar alloys was also explained

Investigation of the properties of Co-rich amorphous ferromagnetic microwires by means of small angle magnetization rotation method

International Nuclear Information System (INIS)

Gudoshnikov, S.; Churyukanova, M.; Kaloshkin, S.; Zhukov, A.; Zhukova, V.; Usov, N.A.

2015-01-01

The amplitude of the second harmonic of the electro-motive force occurring in the receiving pick-up coil when alternating electrical current is flowing through the microwire is measured as a function of applied external magnetic field, at different mechanical tensile stresses. In addition, an analytical expression for the amplitude of the second harmonic of the electro-motive force is derived. Comparing the experimental and theoretical data the saturation magnetization, the magnetostriction constant and the amplitude of the residual quenching stress have been determined for a family of Co-rich glass-coated microwires. - Highlights: • Second harmonic of electro-motive force is measured in amorphous microwire. • Theoretical expression for second harmonic of electro-motive force is derived. • Using these data we determine basic magnetic parameters of Co-rich microwires

Interface topography and residual stress distributions in W coatings for fusion armour applications

Energy Technology Data Exchange (ETDEWEB)

Thomas, G. [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom)], E-mail: g.thomas@cranfield.ac.uk; Vincent, R. [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Matthews, G. [UKAEA Fusion, K2 Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Dance, B. [TWI Ltd, Granta Park, Great Abingdon, Cambridge CB1 6AL (United Kingdom); Grant, P.S. [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom)

2008-03-25

Vacuum plasma sprayed (VPS) tungsten (W) coatings are potential plasma facing components in future fusion power plants. However, the large coefficient of thermal expansion mismatch between W and underlying structural steels and other metallic materials poses a significant problem for manufacturing and service life because of the evolution of large thermally induced stresses leading to failure. In this paper, the effects of the substrate/coating interface 3D geometry on stress distributions are investigated using finite element analysis and VPS experiments to manufacture up to 2 mm thick W coatings. The key factors that affect internal stress distributions during thermal exposure have been identified including graded composition inter-layers, stress concentration effects, mechanical adhesion, and the possible role of segmentation in relieving coating stresses on surface sculptured substrates.

Interface topography and residual stress distributions in W coatings for fusion armour applications

International Nuclear Information System (INIS)

Thomas, G.; Vincent, R.; Matthews, G.; Dance, B.; Grant, P.S.

2008-01-01

Vacuum plasma sprayed (VPS) tungsten (W) coatings are potential plasma facing components in future fusion power plants. However, the large coefficient of thermal expansion mismatch between W and underlying structural steels and other metallic materials poses a significant problem for manufacturing and service life because of the evolution of large thermally induced stresses leading to failure. In this paper, the effects of the substrate/coating interface 3D geometry on stress distributions are investigated using finite element analysis and VPS experiments to manufacture up to 2 mm thick W coatings. The key factors that affect internal stress distributions during thermal exposure have been identified including graded composition inter-layers, stress concentration effects, mechanical adhesion, and the possible role of segmentation in relieving coating stresses on surface sculptured substrates

Surface interactions of a W-DLC-coated biomedical AISI 316L stainless steel in physiological solution.

Science.gov (United States)

Antunes, Renato A; de Lima, Nelson Batista; Rizzutto, Márcia de Almeida; Higa, Olga Zazuco; Saiki, Mitiko; Costa, Isolda

2013-04-01

The corrosion stability of a W-DLC coated surgical AISI 316L stainless steel in Hanks' solution has been evaluated. Particle induced X-ray emission (PIXE) measurements were performed to evaluate the incorporation of potentially bioactive elements from the physiological solution. The film structure was analyzed by X-ray diffractometry and micro-Raman spectroscopy. The wear behavior was assessed using the sphere-on-disc geometry. The in vitro biocompatibility of the W-DLC film was evaluated by cytotoxicity tests. The corrosion resistance of the stainless steel substrate decreased in the presence of the PVD layer. EIS measurements suggest that this behavior was closely related to the corrosion attack through the coating pores. PIXE measurements revealed the presence of Ca and P in the W-DLC film after immersion in Hanks' solution. This result shows that the PIXE technique can be applied to identify and evaluate the incorporation of bioactive elements by W-DLC films. The film showed good wear resistance and biocompatibility.

Amorphous Al-Mn coating on NdFeB magnets: Electrodeposition from AlCl{sub 3}-EMIC-MnCl{sub 2} ionic liquid and its corrosion behavior

Energy Technology Data Exchange (ETDEWEB)

Chen Jing; Xu Bajin [Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Ling Guoping, E-mail: linggp@zju.edu.cn [Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China)

2012-06-15

Amorphous Al-Mn coating was electrodeposited on NdFeB magnets from AlCl{sub 3}-EMIC-MnCl{sub 2} ionic liquid with the pretreatment of anodic electrolytic etching in AlCl{sub 3}-EMIC ionic liquid at room temperature. The microstructure, composition and phase constituents of the coatings were investigated by scanning electron microscopy (SEM), energy-dispersive X-ray spectrometry (EDS), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The corrosion resistance of the coatings was tested by means of potentiodynamic polarization and immersion test in 3.5 wt. % NaCl solution. The results show that anodic electrolytic etching in AlCl{sub 3}-EMIC ionic liquid is a satisfactory pretreatment to remove the surface oxide film and favor the adhesion of the Al-Mn alloy coating to the NdFeB substrate. The amorphous Al-Mn alloy coating provides sacrificial anodic protection for NdFeB. It exhibited good corrosion resistance and significantly reduced the corrosion current density of NdFeB by three orders of magnitude at potentiodynamic polarization. - Highlights: Black-Right-Pointing-Pointer Amorphous Al-Mn alloy coating was electrodeposited on NdFeB magnet from ionic liquid. Black-Right-Pointing-Pointer To remove the surface oxides of NdFeB, anodic etching pretreatment is used. Black-Right-Pointing-Pointer The deposited Al-Mn alloy coating shows high adhesion to the NdFeB substrate. Black-Right-Pointing-Pointer Corrosion tests show that amorphous Al-Mn alloy coating is anodic coating for NdFeB magnet.

Amorphous GaP produced by ion implantation

International Nuclear Information System (INIS)

Shimada, T.; Kato, Y.; Shiraki, Y.; Komatsubara, K.F.

1976-01-01

Two types of non-crystalline states ('disordered' and 'amorphous') of GaP were produced by using ion implantation and post annealing. A structural-phase-transition-like annealing behaviour from the 'disordered' state to the 'amorphous' state was observed. The ion dose dependence and the annealing behaviour of the atomic structure of GaP implanted with 200 keV -N + ions were studied by using electron diffraction, backscattering and volume change measurements. The electronic structure was also investigated by measuring optical absorption and electrical conductivity. The implanted layer gradually loses the crystalline order with the increase of the nitrogen dose. The optical absorption coefficient α and electric conductivity sigma of GaP crystals implanted with 200 keV -N + ions of 1 x 10 16 cm -2 were expressed as αhν = C(hν - E 0 )sup(n) and log sigma = A -BTsup(-1/4), respectively. Moreover, the volume of the implanted layer increased about three percent and the electron diffraction pattern was diffused halo whose intensity monotonically decreases along the radial direction. These results indicate that the as-implanted layer has neither a long range order or short range order ('disordered state'). In the sample implanted at 1 x 10 16 cm -2 , a structural phase-transition-like annealing stage was observed at around 400 0 C. That is, the optical absorption coefficient abruptly fell off from 6 x 10 4 to 7 x 10 3 cm -1 and the volume of the implanted layer decreased about 2% within an increase of less than 10 degrees in the anneal temperature. Moreover, the short range order of the lattice structure appeared in the electron diffraction pattern. According to the backscattering experiment, the heavily implanted GaP was still in the non-crystalline state even after annealing. These facts suggest that heavily implanted GaP, followed by annealing at around 400 0 C, is in the 'amorphous' state, although as-implanted GaP is not in the 'amorphous' state but in the

Tribological properties, corrosion resistance and biocompatibility of magnetron sputtered titanium-amorphous carbon coatings

International Nuclear Information System (INIS)

Dhandapani, Vishnu Shankar; Subbiah, Ramesh; Thangavel, Elangovan; Arumugam, Madhankumar; Park, Kwideok; Gasem, Zuhair M.; Veeraragavan, Veeravazhuthi; Kim, Dae-Eun

2016-01-01

Highlights: • a-C:Ti nanocomposite coatings were prepared on 316L stainless steel by using R.F. magnetron sputtering method. • Properties of the nanocomposite coatings were analyzed with respect to titanium content. • Corrosion resistance, biocompatibility and hydrophobicity of nanocomposite coating were enhanced with increasing titanium content. • Coating with 2.33 at.% titanium showed superior tribological properties compared to other coatings. - Abstract: Amorphous carbon incorporated with titanium (a-C:Ti) was coated on 316L stainless steel (SS) by magnetron sputtering technique to attain superior tribological properties, corrosion resistance and biocompatibility. The morphology, topography and functional groups of the nanostructured a-C:Ti coatings in various concentrations were analyzed using atomic force microscopy (AFM), Raman, X-Ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). Raman and XPS analyses confirmed the increase in sp"2 bonds with increasing titanium content in the a-C matrix. TEM analysis confirmed the composite nature of the coating and the presence of nanostructured TiC for Ti content of 2.33 at.%. This coating showed superior tribological properties compared to the other a-C:Ti coatings. Furthermore, electrochemical corrosion studies were performed against stimulated body fluid medium in which all the a-C:Ti coatings showed improved corrosion resistance than the pure a-C coating. Preosteoblasts proliferation and viability on the specimens were tested and the results showed that a-C:Ti coatings with relatively high Ti (3.77 at.%) content had better biocompatibility. Based on the results of this work, highly durable coatings with good biocompatibility could be achieved by incorporation of optimum amount of Ti in a-C coatings deposited on SS by magnetron sputtering technique.

Nanocrystalline soft ferromagnetic Ni-Co-P thin film on Al alloy by low temperature electroless deposition

International Nuclear Information System (INIS)

Aal, A. Abdel; Shaaban, A.; Hamid, Z. Abdel

2008-01-01

Soft ferromagnetic ternary Ni-Co-P films were deposited onto Al 6061 alloy from low temperature Ni-Co-P electroless plating bath. The effect of deposition parameters, such as time and pH, on the plating rate of the deposit were examined. The results showed that the plating rate is a function of pH bath and the highest coating thickness can be obtained at pH value from 8 to10. The surface morphology, phase structure and the magnetic properties of the prepared films have been investigated using scanning electron microscopy (SEM), X-ray diffraction analysis (XRD) and vibrating magnetometer device (VMD), respectively. The deposit obtained at optimum conditions showed compact and smooth with nodular grains structure and exhibited high magnetic moments and low coercivety. Potentiodynamic polarization corrosion tests were used to study the general corrosion behavior of Al alloys, Ni-P and Ni-Co-P coatings in 3.5% NaCl solution. It was found that Ni-Co-P coated alloy demonstrated higher corrosion resistance than Ni-P coating containing same percent of P due to the Co addition. The Ni-Co-P coating with a combination of high corrosion resistance, high hardness and excellent magnetic properties would be expected to enlarge the applications of the aluminum alloys

In situ atom trapping of Bi on W-coated slotted quartz tube flame atomic absorption spectrometry and interference studies

Energy Technology Data Exchange (ETDEWEB)

Kılınç, Ersin, E-mail: kilincersin@gmail.com [Medical Laboratory Techniques, Vocational Higher School of Healthcare Studies, Mardin Artuklu University, 47200 Mardin (Turkey); Bakırdere, Sezgin [Yıldız Technical University, Art and Science Faculy, Department of Chemistry, Esenler, TR 34220 İstanbul (Turkey); Aydın, Fırat [Dicle University, Faculty of Science, Department of Chemistry, Laboratory of Chemical Analysis, TR 21280 Diyarbakır (Turkey); Ataman, O. Yavuz [Middle East Technical University, Faculty of Arts and Sciences, Department of Chemistry, 06800 Ankara (Turkey)

2013-11-01

Analytical performances of metal coated slotted quartz tube flame atomic absorption spectrometry (SQT-FAAS) and slotted quartz tube in situ atom trapping flame atomic absorption spectrometry (SQT-AT-FAAS) systems were evaluated for determination of Bi. Non-volatile elements such as Mo, Zr, W and Ta were tried as coating materials. It was observed that W-coated SQT gave the best sensitivity for the determination of Bi for SQT-FAAS and SQT-AT-FAAS. The parameters for W-coated SQT-FAAS and W-coated SQT-AT-FAAS were optimized. Sensitivity of FAAS for Bi was improved as 4.0 fold by W-coated SQT-FAAS while 613 fold enhancement in sensitivity was achieved by W-coated SQT-AT-FAAS using 5.0 min trapping with respect to conventional FAAS. MIBK was selected as organic solvent for the re-atomization of Bi from the trapping surface. Limit of detection values for W-coated SQT-FAAS and W-coated SQT-AT-FAAS was obtained as 0.14 μg mL{sup −1} and 0.51 ng mL{sup −1}, respectively. Linear calibration plot was obtained in the range of 2.5–25.0 ng mL{sup −1} for W-coated SQT-AT-FAAS. Accuracy of the W-coated SQT-AT-FAAS system was checked by analyzing a standard reference material, NIST 1643e. - Highlights: • Further increasing in sensitivity of SQT-AT-FAAS was obtained by using a W coated SQT. • 613 fold sensitivity enhancement was achieved by W coated SQT-AT-FAAS versus FAAS. • A sensitive, rapid and simple technique for Bi was developed with an LOD of 0.51 ng mL{sup −1}. • The technique is suggested for laboratories equipped with only a flame AA spectrometer.

In situ atom trapping of Bi on W-coated slotted quartz tube flame atomic absorption spectrometry and interference studies

International Nuclear Information System (INIS)

Kılınç, Ersin; Bakırdere, Sezgin; Aydın, Fırat; Ataman, O. Yavuz

2013-01-01

Analytical performances of metal coated slotted quartz tube flame atomic absorption spectrometry (SQT-FAAS) and slotted quartz tube in situ atom trapping flame atomic absorption spectrometry (SQT-AT-FAAS) systems were evaluated for determination of Bi. Non-volatile elements such as Mo, Zr, W and Ta were tried as coating materials. It was observed that W-coated SQT gave the best sensitivity for the determination of Bi for SQT-FAAS and SQT-AT-FAAS. The parameters for W-coated SQT-FAAS and W-coated SQT-AT-FAAS were optimized. Sensitivity of FAAS for Bi was improved as 4.0 fold by W-coated SQT-FAAS while 613 fold enhancement in sensitivity was achieved by W-coated SQT-AT-FAAS using 5.0 min trapping with respect to conventional FAAS. MIBK was selected as organic solvent for the re-atomization of Bi from the trapping surface. Limit of detection values for W-coated SQT-FAAS and W-coated SQT-AT-FAAS was obtained as 0.14 μg mL −1 and 0.51 ng mL −1 , respectively. Linear calibration plot was obtained in the range of 2.5–25.0 ng mL −1 for W-coated SQT-AT-FAAS. Accuracy of the W-coated SQT-AT-FAAS system was checked by analyzing a standard reference material, NIST 1643e. - Highlights: • Further increasing in sensitivity of SQT-AT-FAAS was obtained by using a W coated SQT. • 613 fold sensitivity enhancement was achieved by W coated SQT-AT-FAAS versus FAAS. • A sensitive, rapid and simple technique for Bi was developed with an LOD of 0.51 ng mL −1 . • The technique is suggested for laboratories equipped with only a flame AA spectrometer

Densities of molten Ni-(Cr, Co, W) superalloys

Institute of Scientific and Technical Information of China (English)

XIAO Feng; YANG Ren-hui; FANG Liang; LIU Lan-xiao; ZHAO Hong-kai

2008-01-01

In order to obtain more accurate density for molten Ni-(Cr, Co, W) binary alloy, the densities of molten pure Ni and Ni-Cr, Ni-Co, Ni-W alloys were measured with a sessile drop method. It is found that the measured densities of molten pure Ni and Ni-Cr, Ni-Co, Ni-W alloys decrease with increasing temperature in the experimental temperature range. The density of alloys increases with increasing W and Co concentrations while it decreases with increasing Cr concentration in the alloy at 1 773-1 873 K. The molar volume of Ni-based alloys increases with increasing W concentration while it decreases with increasing Co concentration. The effect of Cr concentration on the molar volume of the alloy is little in the studied concentration range. The accommodation among atomic species was analyzed. The deviation of molar volume from ideal mixing shows an ideal mixing of Ni-(Cr, Co, W) binary alloys.

Microstructure, chemical states, and mechanical properties of V–C–Co coatings prepared by non-reactive magnetron sputtering

International Nuclear Information System (INIS)

Zhang, Xiaojuan; Wang, Bo; Zhan, Zhaolin; Huang, Feng

2013-01-01

V–C–Co coatings have been prepared by non-reactive magnetron co-sputtering from VC and Co targets. The microstructure, chemical states, and mechanical properties are examined as a function of Co content in the coatings. The coatings are dense, with columnar growth structures. High resolution transmission electron microscopy (HRTEM) studies identify a nanocomposite microstructure for the 12.4 at.% Co coating, in which ligament-like Co-rich regions partially separate the nanocrystalline VC grains. X-ray photoelectron spectroscopy studies reveal a noticeable charge transfer from Co 2p states to C 1s states. This charge transfer, in addition to the ligament-like Co-rich regions as revealed by HRTEM, points to the formation of a strong Co/VC interface. The nanoindentation hardness of the coatings drops steadily with the Co content, from 29 GPa for pure VC to ∼ 21 GPa for the 12.4 at.% Co coating. Meanwhile, the plasticity characteristic increased from 0.42 to 0.53. - Highlights: • Nanocomposite V–C–Co coatings with strong Co/VC interfaces were formed. • Found nanocrystalline VC grains separated by ∼ 1 nm thin Co-rich ligaments. • A noticeable amount of C-Co bonds between VC and Co is identified. • V–C–Co coatings exhibited a higher plasticity characteristic than VC

Microstructure, chemical states, and mechanical properties of V–C–Co coatings prepared by non-reactive magnetron sputtering

Energy Technology Data Exchange (ETDEWEB)

Zhang, Xiaojuan [Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang 315201 (China); School of Materials Science and Engineering, Kunming University of Science and Technology, Kunming, Yunnan 650000 (China); Wang, Bo [Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang 315201 (China); Zhan, Zhaolin [School of Materials Science and Engineering, Kunming University of Science and Technology, Kunming, Yunnan 650000 (China); Huang, Feng, E-mail: huangfeng@nimte.ac.cn [Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang 315201 (China)

2013-07-01

V–C–Co coatings have been prepared by non-reactive magnetron co-sputtering from VC and Co targets. The microstructure, chemical states, and mechanical properties are examined as a function of Co content in the coatings. The coatings are dense, with columnar growth structures. High resolution transmission electron microscopy (HRTEM) studies identify a nanocomposite microstructure for the 12.4 at.% Co coating, in which ligament-like Co-rich regions partially separate the nanocrystalline VC grains. X-ray photoelectron spectroscopy studies reveal a noticeable charge transfer from Co 2p states to C 1s states. This charge transfer, in addition to the ligament-like Co-rich regions as revealed by HRTEM, points to the formation of a strong Co/VC interface. The nanoindentation hardness of the coatings drops steadily with the Co content, from 29 GPa for pure VC to ∼ 21 GPa for the 12.4 at.% Co coating. Meanwhile, the plasticity characteristic increased from 0.42 to 0.53. - Highlights: • Nanocomposite V–C–Co coatings with strong Co/VC interfaces were formed. • Found nanocrystalline VC grains separated by ∼ 1 nm thin Co-rich ligaments. • A noticeable amount of C-Co bonds between VC and Co is identified. • V–C–Co coatings exhibited a higher plasticity characteristic than VC.

Multi-layered electroless Ni-P coatings on powder-sintered Nd-Fe-B permanent magnet

International Nuclear Information System (INIS)

Chen Zhong; Ng, Alice; Yi Jianzhang; Chen Xingfu

2006-01-01

This paper has shown a successful protective coating scheme for powder-sintered Nd-Fe-B permanent magnet using multi-layered electroless nickel (EN) deposition. A low-phosphorus nickel layer is plated with an alkaline EN solution first, followed by a high-phosphorus nickel layer plated with an acidic solution. An additional topcoat by medium-phosphorus nickel on the high-phosphorus coating is also explored. It is shown that the high-phosphorus nickel layer coated in acidic solution provides the best corrosion protection because of its dense amorphous structure. The medium phosphorus topcoat is also dense and is able to provide reasonable corrosion resistance. The low-phosphorus layer itself does not have enough corrosion resistance; its main role is to provide an intermediate coating on the powder-sintered magnet. X-ray diffraction measurement shows that the low-phosphorus coating consists of nano-crystallines, and the high- and the medium-phosphorus coatings are dominated by amorphous structure. Microscopic observation and scratch test on these composite coatings demonstrate good adhesion between the magnet and the coatings. Remanence and coercivity of the plated magnet decrease with the applied coatings, but measured values are still very attractive for practical applications among known hard magnets

Fabrication and characterization of CaP-coated nanotube arrays

International Nuclear Information System (INIS)

Kung, Kuan-Chen; Chen, Jia-Ling; Liu, Yen-Ting; Lee, Tzer-Min

2015-01-01

Modified anodization techniques have been shown to improve the biocompatibility of titanium. This study demonstrated the anodic formation of self-organized nanotube arrays on titanium from an electrolyte solution containing 1 M H 3 PO 4 and 1 wt% hydrofluoric acid (HF). Our aim was to investigate the effects of sputter-deposited CaP on nanotube arrays. SEM images revealed a surface with uniform morphology and an average pore diameter of 29 nm. XRD results indicated that the phase of the nanotube arrays was amorphous. Electron spectroscopy for chemical analysis (ESCA) confirmed that the nanotube arrays were coated with calcium and phosphorus. Cell culture experiments using human osteosarcoma (HOS) cells demonstrated that the CaP/nanotube arrays had a pronounced effect on initial cell attachment as well as on the number of cells at 1, 7, and 14 days. Compared to as-polished titanium, the CaP/nanotube arrays accelerated cell proliferation, attachment, and spreading. Our results demonstrate the pronounced effects of CaP/nanotube arrays on the biological responses of HOS cells. - Highlights: • Self-organized nanotube arrays were anodically formed on titanium. • Surfaces of nanotube arrays exhibited uniform morphology and pore size. • According to ESCA results, Ca and P were successfully coated on nanotube arrays. • CaP/nanotube arrays accelerated the attachment and spreading of cells. • CaP/nanotube arrays were shown to affect biological responses of cells

Fabrication and characterization of CaP-coated nanotube arrays

Energy Technology Data Exchange (ETDEWEB)

Kung, Kuan-Chen; Chen, Jia-Ling [Institute of Oral Medicine, National Cheng Kung University, Tainan 701, Taiwan (China); Liu, Yen-Ting [Department of Materials Science and Engineering, National Cheng Kung University, Tainan 701, Taiwan (China); Lee, Tzer-Min, E-mail: tmlee@mail.ncku.edu.tw [Institute of Oral Medicine, National Cheng Kung University, Tainan 701, Taiwan (China); Medical Device Innovation Center, National Cheng Kung University, Tainan 701, Taiwan (China); School of Dentistry, Kaohsiung Medical University, Kaohsiung 807, Taiwan (China)

2015-03-01

Modified anodization techniques have been shown to improve the biocompatibility of titanium. This study demonstrated the anodic formation of self-organized nanotube arrays on titanium from an electrolyte solution containing 1 M H{sub 3}PO{sub 4} and 1 wt% hydrofluoric acid (HF). Our aim was to investigate the effects of sputter-deposited CaP on nanotube arrays. SEM images revealed a surface with uniform morphology and an average pore diameter of 29 nm. XRD results indicated that the phase of the nanotube arrays was amorphous. Electron spectroscopy for chemical analysis (ESCA) confirmed that the nanotube arrays were coated with calcium and phosphorus. Cell culture experiments using human osteosarcoma (HOS) cells demonstrated that the CaP/nanotube arrays had a pronounced effect on initial cell attachment as well as on the number of cells at 1, 7, and 14 days. Compared to as-polished titanium, the CaP/nanotube arrays accelerated cell proliferation, attachment, and spreading. Our results demonstrate the pronounced effects of CaP/nanotube arrays on the biological responses of HOS cells. - Highlights: • Self-organized nanotube arrays were anodically formed on titanium. • Surfaces of nanotube arrays exhibited uniform morphology and pore size. • According to ESCA results, Ca and P were successfully coated on nanotube arrays. • CaP/nanotube arrays accelerated the attachment and spreading of cells. • CaP/nanotube arrays were shown to affect biological responses of cells.

On the structural and magnetic properties of amorphous Fe84-xWxB16 alloys in dependence of W content

International Nuclear Information System (INIS)

Novakova, A.A.; Sidorova, G.V.; Katsnelson, A.A.; Szasz, A.; Kojnok, J.

1990-01-01

A series of rapidly solidificated amorphous Fe 84-x W x B 16 (x=0-5) alloys have been studied. A strictly linear decrease of H eff versus concentration of W has been observed by Moessbauer spectroscopy. (orig.)

Hot Melt Extrusion and Spray Drying of Co-amorphous Indomethacin-Arginine With Polymers

DEFF Research Database (Denmark)

Lenz, Elisabeth; Löbmann, Korbinian; Rades, Thomas

2017-01-01

Co-amorphous drug-amino acid systems have gained growing interest as an alternative to common amorphous formulations which contain polymers as stabilizers. Several preparation methods have recently been investigated, including vibrational ball milling on a laboratory scale or spray drying......, and stability. Results were compared to those of spray-dried formulations with the same compositions and to spray-dried indomethacin-copovidone. Overall, stable co-amorphous systems could be prepared by extrusion without or with copovidone, which exhibited comparable molecular interaction properties...... to the respective spray-dried products, while phase separation was detected by differential scanning calorimetry in several cases. The formulations containing indomethacin in combination with arginine and copovidone showed enhanced dissolution behavior over the formulations with only copovidone or arginine....

Properties of ternary NiFeW alloy coating by jet electrodeposition

Indian Academy of Sciences (India)

In this paper, ternary NiFeW alloy coatings were prepared by jet electrodeposition, and the effects of lord salt concentration, jet speed, current density and temperature on the properties of the coatings, including the composition, microhardness, surface morphology, structure and corrosion resistance, were investigated.

Controllable Fabrication of Amorphous Co-Ni Pyrophosphates for Tuning Electrochemical Performance in Supercapacitors.

Science.gov (United States)

Chen, Chen; Zhang, Ning; He, Yulu; Liang, Bo; Ma, Renzhi; Liu, Xiaohe

2016-09-07

Incorporation of two transition metals offers an effective method to enhance the electrochemical performance in supercapacitors for transition metal compound based electrodes. However, such a configuration is seldom concerned in pyrophosphates. Here, amorphous phase Co-Ni pyrophosphates are fabricated as electrodes in supercapacitors. Through controllably adjusting the ratios of Co and Ni as well as the calcination temperature, the electrochemical performance can be tuned. An optimized amorphous Ni-Co pyrophosphate exhibits much higher specific capacitance than monometallic Ni and Co pyrophosphates and shows excellent cycling ability. When employing Ni-Co pyrophosphates as positive electrode and activated carbon as a negative electrode, the fabricated asymmetric supercapacitor cell exhibits favorable capacitance and cycling ability. This study provides facile methods to improve the transition metal pyrophosphate electrodes for efficient electrodes in electrochemical energy storage devices.

CO{sub 2} laser coating of nanodiamond on aluminum using an annular beam

Energy Technology Data Exchange (ETDEWEB)

Blum, Rodger; Molian, Pal, E-mail: molian@iastate.edu

2014-01-01

Laser coating of nanodiamond (ND) on aluminum alloy A319 substrate was investigated using a diffraction-free ring beam. A 1000 W continuous wave CO{sub 2} laser in the ring beam configuration heated the 25–35 μm thick electrostatically sprayed ND powder layers on aluminum surface, melted a very thin layer (10 μm) of aluminum in a controlled fashion and caused phase transition of ND to form 50–60 μm thick ND/diamond-like carbon (DLC) coating. Significant improvements in friction, wear resistance and surface finish were observed in the ring beam method over the traditional Gaussian beam method suggesting that these thick (50–60 μm) ND/DLC laser coatings can outperform the currently used thin (<4 μm) chemically vapor deposited DLC coatings for aluminum parts in automobiles.

Effect of Co content on structure and magnetic behaviors of high induction Fe-based amorphous alloys

Energy Technology Data Exchange (ETDEWEB)

Roy, Rajat K., E-mail: rajat@nmlindia.org; Panda, Ashis K.; Mitra, Amitava

2016-11-15

The replacement of Fe with Co is investigated in the (Fe{sub 1−x}Co{sub x}){sub 79}Si{sub 8.5}B{sub 8.5}Nb{sub 3}Cu{sub 1} (x=0, 0.05, 0.2, 0.35, 0.5) amorphous alloys. The alloys are synthesized in the forms of ribbons by single roller melt spinning technique, and the structural and magnetic properties of annealed ribbons are characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM), B–H curve tracer, respectively. All as-cast alloys are structurally amorphous, however, their magnetic properties are varying with Co addition. The Co addition within 5–20 at% results in moderate thermal stability, saturation induction, Curie temperature and lowest coercivity, while 35 at% Co causes highest saturation induction, coercivity, Curie temperature and lowest thermal stability. On devitrification, the magnetic properties change with the generation of α-FeCo nanocrystallites and (FeCo){sub 23}B{sub 6}, Fe{sub 2}B phases during primary and secondary crystallization stages, respectively. A small amount Co is advantageous for maintaining finer nanocrystallites in amorphous matrix even after annealing at 600 °C, leading to high saturation magnetization (>1.5 T) and low coercivity (~35 A/m). The improved magnetic properties at elevated temperatures indicate these alloys have a potential for high frequency transformer core applications. - Highlights: • The structural and magnetic behaviors of Fe based amorphous alloys have been investigated with the effect of Co content. • The Co has no adverse effect on amorphization of alloys. • A small amount Co causes the superior improvement of magnetic properties at elevated temperatures. • Therefore, it is important not only for academic research but also for industrial applied research.

Tribological behavior of W-DLC coated rubber seals

NARCIS (Netherlands)

Pei, Y.T.; Bui, X.L.; Zhou, X.B.; Hosson, J.Th.M. De

2008-01-01

Tungsten-containing diamond-like carbon (W-DLC) coatings have been deposited on FKM (fluorocarbon) and HNBR (hydrogenated nitrile butadiene) rubbers via unbalanced magnetron reactive sputtering from a WC target in a C2H2/Ar plasma. The surface morphology and fracture cross sections of uncoated and

Photoemission studies of amorphous silicon induced by P + ion implantation

Science.gov (United States)

Petö, G.; Kanski, J.

1995-12-01

An amorphous Si layer was formed on a Si (1 0 0) surface by P + implantation at 80 keV. This layer was investigated by means of photoelectron spectroscopy. The resulting spectra are different from earlier spectra on amorphous Si prepared by e-gun evaporation or cathode sputtering. The differences consist of a decreased intensity in the spectral region corresponding to p-states, and appearace of new states at higher binding energy. Qualitativity similar results have been reported for Sb implanted amorphous Ge and the modification seems to be due to the changed short range order.

Multi-jump magnetic switching in ion-beam sputtered amorphous Co20Fe60B20 thin films

International Nuclear Information System (INIS)

Raju, M.; Chaudhary, Sujeet; Pandya, D. K.

2013-01-01

Unconventional multi-jump magnetization reversal and significant in-plane uniaxial magnetic anisotropy (UMA) in the ion-beam sputtered amorphous Co 20 Fe 60 B 20 (5–75 nm) thin films grown on Si/amorphous SiO 2 are reported. While such multi-jump behavior is observed in CoFeB(10 nm) film when the magnetic field is applied at 10°–20° away from the easy-axis, the same is observed in CoFeB(12.5 nm) film when the magnetic field is 45°–55° away from easy-axis. Unlike the previous reports of multi-jump switching in epitaxial films, their observance in the present case of amorphous CoFeB is remarkable. This multi-jump switching is found to disappear when the films are crystallized by annealing at 420 °C. The deposition geometry and the energy of the sputtered species appear to intrinsically induce a kind of bond orientation anisotropy in the films, which leads to the UMA in the as-grown amorphous CoFeB films. Exploitation of such multi-jump switching in amorphous CoFeB thin films could be of technological significance because of their applications in spintronic devices

Hierarchical Mn2O3 Microspheres In-Situ Coated with Carbon for Supercapacitors with Highly Enhanced Performances

Science.gov (United States)

Gong, Feilong; Lu, Shuang; Peng, Lifang; Zhou, Jing; Kong, Jinming; Jia, Dianzeng; Li, Feng

2017-01-01

Porous Mn2O3 microspheres have been synthesized and in-situ coated with amorphous carbon to form hierarchical C@Mn2O3 microspheres by first producing MnCO3 microspheres in solvothermal reactions, and then annealing at 500 °C. The self-assembly growth of MnCO3 microspheres can generate hollow structures inside each of the particles, which can act as micro-reservoirs to store biomass-glycerol for generating amorphous carbon onto the surfaces of Mn2O3 nanorods consisting of microspheres. The C@Mn2O3 microspheres, prepared at 500 °C, exhibit highly enhanced pseudocapacitive performances when compared to the particles after annealed at 400 °C and 600 °C. Specifically, the C@Mn2O3 microspheres prepared at 500 °C show high specific capacitances of 383.87 F g−1 at current density of 0.5 A g−1, and excellent cycling stability of 90.47% of its initial value after cycling for 5000 times. The asymmetric supercapacitors assembled with C@Mn2O3 microspheres after annealed at 500 °C and activated carbon (AC) show an energy density of up to 77.8 Wh kg−1 at power density of 500.00 W kg−1, and a maximum power density of 20.14 kW kg−1 at energy density of 46.8 Wh kg−1. We can attribute the enhanced electrochemical performances of the materials to their three-dimensional (3D) hierarchical structure in-situ coated with carbon. PMID:29168756

Hierarchical Mn2O3 Microspheres In-Situ Coated with Carbon for Supercapacitors with Highly Enhanced Performances

Directory of Open Access Journals (Sweden)

Feilong Gong

2017-11-01

Full Text Available Porous Mn2O3 microspheres have been synthesized and in-situ coated with amorphous carbon to form hierarchical C@Mn2O3 microspheres by first producing MnCO3 microspheres in solvothermal reactions, and then annealing at 500 °C. The self-assembly growth of MnCO3 microspheres can generate hollow structures inside each of the particles, which can act as micro-reservoirs to store biomass-glycerol for generating amorphous carbon onto the surfaces of Mn2O3 nanorods consisting of microspheres. The C@Mn2O3 microspheres, prepared at 500 °C, exhibit highly enhanced pseudocapacitive performances when compared to the particles after annealed at 400 °C and 600 °C. Specifically, the C@Mn2O3 microspheres prepared at 500 °C show high specific capacitances of 383.87 F g−1 at current density of 0.5 A g−1, and excellent cycling stability of 90.47% of its initial value after cycling for 5000 times. The asymmetric supercapacitors assembled with C@Mn2O3 microspheres after annealed at 500 °C and activated carbon (AC show an energy density of up to 77.8 Wh kg−1 at power density of 500.00 W kg−1, and a maximum power density of 20.14 kW kg−1 at energy density of 46.8 Wh kg−1. We can attribute the enhanced electrochemical performances of the materials to their three-dimensional (3D hierarchical structure in-situ coated with carbon.

FY05 HPCRM Annual Report: High-Performance Corrosion-Resistant Iron-Based Amorphous Metal Coatings

Energy Technology Data Exchange (ETDEWEB)

Farmer, J; Choi, J; Haslam, J; Day, S; Yang, N; Headley, T; Lucadamo, G; Yio, J; Chames, J; Gardea, A; Clift, M; Blue, G; Peters, W; Rivard, J; Harper, D; Swank, D; Bayles, R; Lemieux, E; Brown, R; Wolejsza, T; Aprigliano, L; Branagan, D; Marshall, M; Meacham, B; Aprigliano, L; Branagan, D; Marshall, M; Meacham, B; Lavernia, E; Schoenung, J; Ajdelsztajn, L; Dannenberg, J; Graeve, O; Lewandowski, J; Perepezko, J; Hildal, K; Kaufman, L; Boudreau, J

2007-09-20

New corrosion-resistant, iron-based amorphous metals have been identified from published data or developed through combinatorial synthesis, and tested to determine their relative corrosion resistance. Many of these materials can be applied as coatings with advanced thermal spray technology. Two compositions have corrosion resistance superior to wrought nickel-based Alloy C-22 (UNS No. N06022) in some very aggressive environments, including concentrated calcium-chloride brines at elevated temperature. Two Fe-based amorphous metal formulations have been found that appear to have corrosion resistance comparable to, or better than that of Ni-based Alloy C-22, based on breakdown potential and corrosion rate. Both Cr and Mo provide corrosion resistance, B enables glass formation, and Y lowers critical cooling rate (CCR). SAM1651 has yttrium added, and has a nominal critical cooling rate of only 80 Kelvin per second, while SAM2X7 (similar to SAM2X5) has no yttrium, and a relatively high critical cooling rate of 610 Kelvin per second. Both amorphous metal formulations have strengths and weaknesses. SAM1651 (yttrium added) has a low critical cooling rate (CCR), which enables it to be rendered as a completely amorphous thermal spray coating. Unfortunately, it is relatively difficult to atomize, with powders being irregular in shape. This causes the powder to be difficult to pneumatically convey during thermal spray deposition. Gas atomized SAM1651 powder has required cryogenic milling to eliminate irregularities that make flow difficult. SAM2X5 (no yttrium) has a high critical cooling rate, which has caused problems associated with devitrification. SAM2X5 can be gas atomized to produce spherical powders of SAM2X5, which enable more facile thermal spray deposition. The reference material, nickel-based Alloy C-22, is an outstanding corrosion-resistant engineering material. Even so, crevice corrosion has been observed with C-22 in hot sodium chloride environments without buffer

FY05 HPCRM Annual Report: High-Performance Corrosion-Resistant Iron-Based Amorphous Metal Coatings

International Nuclear Information System (INIS)

Farmer, J; Choi, J; Haslam, J; Day, S; Yang, N; Headley, T; Lucadamo, G; Yio, J; Chames, J; Gardea, A; Clift, M; Blue, G; Peters, W; Rivard, J; Harper, D; Swank, D; Bayles, R; Lemieux, E; Brown, R; Wolejsza, T; Aprigliano, L; Branagan, D; Marshall, M; Meacham, B; Aprigliano, L; Branagan, D; Marshall, M; Meacham, B; Lavernia, E; Schoenung, J; Ajdelsztajn, L; Dannenberg, J; Graeve, O; Lewandowski, J; Perepezko, J; Hildal, K; Kaufman, L; Boudreau, J

2007-01-01

New corrosion-resistant, iron-based amorphous metals have been identified from published data or developed through combinatorial synthesis, and tested to determine their relative corrosion resistance. Many of these materials can be applied as coatings with advanced thermal spray technology. Two compositions have corrosion resistance superior to wrought nickel-based Alloy C-22 (UNS No. N06022) in some very aggressive environments, including concentrated calcium-chloride brines at elevated temperature. Two Fe-based amorphous metal formulations have been found that appear to have corrosion resistance comparable to, or better than that of Ni-based Alloy C-22, based on breakdown potential and corrosion rate. Both Cr and Mo provide corrosion resistance, B enables glass formation, and Y lowers critical cooling rate (CCR). SAM1651 has yttrium added, and has a nominal critical cooling rate of only 80 Kelvin per second, while SAM2X7 (similar to SAM2X5) has no yttrium, and a relatively high critical cooling rate of 610 Kelvin per second. Both amorphous metal formulations have strengths and weaknesses. SAM1651 (yttrium added) has a low critical cooling rate (CCR), which enables it to be rendered as a completely amorphous thermal spray coating. Unfortunately, it is relatively difficult to atomize, with powders being irregular in shape. This causes the powder to be difficult to pneumatically convey during thermal spray deposition. Gas atomized SAM1651 powder has required cryogenic milling to eliminate irregularities that make flow difficult. SAM2X5 (no yttrium) has a high critical cooling rate, which has caused problems associated with devitrification. SAM2X5 can be gas atomized to produce spherical powders of SAM2X5, which enable more facile thermal spray deposition. The reference material, nickel-based Alloy C-22, is an outstanding corrosion-resistant engineering material. Even so, crevice corrosion has been observed with C-22 in hot sodium chloride environments without buffer

Sintering of MnCo2O4 coatings prepared by electrophoretic deposition

DEFF Research Database (Denmark)

Bobruk, M.; Molin, Sebastian; Chen, Ming

2018-01-01

Sintering of MnCo2O4 coatings prepared by electrophoretic deposition on steel substrates has been studied in air and in reducing-oxidizing atmosphere. Effect of temperature and pO2 on the resulting coating density was evaluated from scanning electron microscopy images of polished cross sections...

Effects of heat treatment on the microstructure of amorphous boron carbide coating deposited on graphite substrates by chemical vapor deposition

International Nuclear Information System (INIS)

Li Siwei; Zeng Bin; Feng Zude; Liu Yongsheng; Yang Wenbin; Cheng Laifei; Zhang Litong

2010-01-01

A two-layer boron carbide coating is deposited on a graphite substrate by chemical vapor deposition from a CH 4 /BCl 3 /H 2 precursor mixture at a low temperature of 950 o C and a reduced pressure of 10 KPa. Coated substrates are annealed at 1600 o C, 1700 o C, 1800 o C, 1900 o C and 2000 o C in high purity argon for 2 h, respectively. Structural evolution of the coatings is explored by electron microscopy and spectroscopy. Results demonstrate that the as-deposited coating is composed of pyrolytic carbon and amorphous boron carbide. A composition gradient of B and C is induced in each deposition. After annealing, B 4 C crystallites precipitate out of the amorphous boron carbide and grow to several hundreds nanometers by receiving B and C from boron-doped pyrolytic carbon. Energy-dispersive spectroscopy proves that the crystallization is controlled by element diffusion activated by high temperature annealing, after that a larger concentration gradient of B and C is induced in the coating. Quantified Raman spectrum identifies a graphitization enhancement of pyrolytic carbon. Transmission electron microscopy exhibits an epitaxial growth of B 4 C at layer/layer interface of the annealed coatings. Mechanism concerning the structural evolution on the basis of the experimental results is proposed.

Low-emissivity coating of amorphous diamond-like carbon/Ag-alloy multilayer on glass

International Nuclear Information System (INIS)

Chiba, Kiyoshi; Takahashi, Toshiyuki; Kageyama, Takashi; Oda, Hironori

2005-01-01

Transparent low-emissivity (low-e) coatings comprising dielectrics of amorphous diamond-like carbon (DLC) and Ag-alloy films are investigated. All films have been prepared by dc magnetron sputtering. An index of refraction of the DLC film deposited in a gas mixture of Ar/H 2 (4%) shows n = 1.80 + 0.047i at 500 nm wavelength. A multilayer stack of DLC (70 nm thick)/Ag 87.5 Cu 12.5 -alloy (10 nm)/DLC (140 nm)/Ag 87.5 Cu 12.5 -alloy (10 nm)/DLC (70 nm) has revealed clear interference spectra with spectra selectivity. This coating performs low emittance less than 0.1 for black body radiation at 297 K, exhibiting a transparent heat mirror property embedded in DLC films

DC and AC linear magnetic field sensor based on glass coated amorphous microwires with Giant Magnetoimpedance

International Nuclear Information System (INIS)

García-Chocano, Víctor Manuel; García-Miquel, Héctor

2015-01-01

Giant Magnetoimpedance (GMI) effect has been studied in amorphous glass-coated microwires of composition (Fe 6 Co 94 ) 72.5 Si 12.5 B 15 . The impedance of a 1.5 cm length sample has been characterized by using constant AC currents in the range of 400 µA–4 mA at frequencies from 7 to 15 MHz and DC magnetic fields from −900 to 900 A/m. Double peak responses have been obtained, showing GMI ratios up to 107%. A linear magnetic field sensor for DC and AC field has been designed, using two microwires connected in series with a magnetic bias of 400 A/m with opposite direction in each microwire in order to obtain a linear response from ±70 (A/m) rms for AC magnetic field, and ±100 A/m for DC magnetic field. A closed loop feedback circuit has been implemented to extend the linear range to ±1 kA/m for DC magnetic field. - Highlights: • Giant Magneto Impedance phenomenon has been studied in amorphous microwires. • A combination of two microwires with a bias field has been developed to get a linear response. • An electronic circuit has been developed to obtain a sensor with a linear response. • A feedback coil have been added to increase the measurable range of the sensor

Moessbauer study of amorphous Fe-P alloys

International Nuclear Information System (INIS)

Takacs, L.; Toth-Kadar, E.

1981-01-01

Preliminary Moessbauer results are represented on electrodeposited Fe-P amorphous alloys. Very broad hyperfine field distributions and relatively large isomer shifts have been found. Problems worth of further investigation are discussed in details. (author)

Substrate temperature influence on the trombogenicity in amorphous carbon nitride thin coatings

International Nuclear Information System (INIS)

Galeano-Osorio, D.S.; Vargas, S.; Lopez-Cordoba, L.M.; Ospina, R.; Restrepo-Parra, E.; Arango, P.J.

2010-01-01

Carbon nitride thin films were obtained through plasma assisted physical vapor deposition technique by pulsed arc, varying the substrate temperature and investigating the influence of this parameter on the films hemocompatibility. For obtaining approaches of blood compatibility, environmental scanning electron microscopy (ESEM) was used in order to study the platelets adherence and their morphology. Moreover, the elemental chemical composition was determined by using energy dispersive spectroscopy (EDS), finding C, N and O. The coatings hemocompatibility was evaluated by in vitro thrombogenicity test, whose results were correlated with the microstructure and roughness of the films obtained. During the films growth process, the substrate temperature was varied, obtaining coatings under different temperatures, room temperature (T room ), 100 deg. C, 150 deg. C and 200 deg. C. Parameters as interelectrodic distance, voltage, work pressure and number of discharges, were remained constant. By EDS, carbon and nitrogen were found in the films. Visible Raman spectroscopy was used, and it revealed an amorphous lattice, with graphitic process as the substrate temperature was increased. However, at a critical temperature of 150 deg. C, this tendency was broken, and the film became more amorphous. This film showed the lowest roughness, 2 ± 1 nm. This last characteristic favored the films hemocompatibility. Also, it was demonstrated that the blood compatibility of carbon nitride films obtained were affected by the I D /I G or sp 3 /sp 2 ratio and not by the absolute sp 3 or sp 2 concentration.

Time series pCO2 at a coastal mooring: Internal consistency, seasonal cycles, and interannual variability

Science.gov (United States)

Reimer, Janet J.; Cai, Wei-Jun; Xue, Liang; Vargas, Rodrigo; Noakes, Scott; Hu, Xinping; Signorini, Sergio R.; Mathis, Jeremy T.; Feely, Richard A.; Sutton, Adrienne J.; Sabine, Christopher; Musielewicz, Sylvia; Chen, Baoshan; Wanninkhof, Rik

2017-08-01

Marine carbonate system monitoring programs often consist of multiple observational methods that include underway cruise data, moored autonomous time series, and discrete water bottle samples. Monitored parameters include all, or some of the following: partial pressure of CO2 of the water (pCO2w) and air, dissolved inorganic carbon (DIC), total alkalinity (TA), and pH. Any combination of at least two of the aforementioned parameters can be used to calculate the others. In this study at the Gray's Reef (GR) mooring in the South Atlantic Bight (SAB) we: examine the internal consistency of pCO2w from underway cruise, moored autonomous time series, and calculated from bottle samples (DIC-TA pairing); describe the seasonal to interannual pCO2w time series variability and air-sea flux (FCO2), as well as describe the potential sources of pCO2w variability; and determine the source/sink for atmospheric pCO2. Over the 8.5 years of GR mooring time series, mooring-underway and mooring-bottle calculated-pCO2w strongly correlate with r-values > 0.90. pCO2w and FCO2 time series follow seasonal thermal patterns; however, seasonal non-thermal processes, such as terrestrial export, net biological production, and air-sea exchange also influence variability. The linear slope of time series pCO2w increases by 5.2 ± 1.4 μatm y-1 with FCO2 increasing 51-70 mmol m-2 y-1. The net FCO2 sign can switch interannually with the magnitude varying greatly. Non-thermal pCO2w is also increasing over the time series, likely indicating that terrestrial export and net biological processes drive the long term pCO2w increase.

Effects of lithium-active manganese trioxide coating on the structural and electrochemical characteristics of LiNi{sub 0.5}Co{sub 0.2}Mn{sub 0.3}O{sub 2} as cathode materials for lithium ion battery

Energy Technology Data Exchange (ETDEWEB)

Li, Lingjun [School of Physics and Electronic Science, Changsha University of Science and Technology, Changsha 410114 (China); Department of Mechanical and Biomedical Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon (Hong Kong); Yao, Qi [School of Physics and Electronic Science, Changsha University of Science and Technology, Changsha 410114 (China); Chen, Zhaoyong, E-mail: csullj@hotmail.com [School of Physics and Electronic Science, Changsha University of Science and Technology, Changsha 410114 (China); Song, Liubin [Hunan Provincial Key Laboratory of Materials Protection for Electric Power and Transportation, School of Chemistry and Biological Engineering, Changsha University of Science and Technology, Hunan, Changsha 410004 (China); Xie, Tian; Zhu, Huali; Duan, Junfei [School of Physics and Electronic Science, Changsha University of Science and Technology, Changsha 410114 (China); Zhang, Kaili, E-mail: kaizhang@cityu.edu.hk [Department of Mechanical and Biomedical Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon (Hong Kong)

2015-11-25

Li{sub 2}MnO{sub 3}-coated LiNi{sub 0.5}Co{sub 0.2}Mn{sub 0.3}O{sub 2} materials are successfully synthesized by sol–gel method. The effects of various pH values and Li{sub 2}MnO{sub 3} contents on the structural and electrochemical properties of LiNi{sub 0.5}Co{sub 0.2}Mn{sub 0.3}O{sub 2} cathode materials are systematically investigated, respectively. Scanning electron microscope, transmission electron microscope and energy dispersive spectrometer confirm that the particles of LiNi{sub 0.5}Co{sub 0.2}Mn{sub 0.3}O{sub 2} are completely coated by crystalline Li{sub 2}MnO{sub 3} phase. Electrochemical tests show that suitable Li{sub 2}MnO{sub 3}-coated samples exhibit higher rate capacity and better cycling performance than those of the pristine one. This improvement can be attributed to the synergetic contribution from the neutral pH value and appropriate Li{sub 2}MnO{sub 3} amount. The neutral pH environment can protect the core material from damaging during the coating process and is conducive to relieving the rapid moisture uptaking problem of LiNi{sub 0.5}Co{sub 0.2}Mn{sub 0.3}O{sub 2}. While, suitable Li{sub 2}MnO{sub 3} coating can protect the bulk from directly contacting the electrolyte and offer a fast Li{sup +} diffusion path at the interface of bulk and electrolyte. - Graphical abstract: The 5% Li{sub 2}MnO{sub 3}-coated LiNi{sub 0.5}Co{sub 0.2}Mn{sub 0.3}O{sub 2} sample, modified at pH 6, exhibits a conformal and amorphous coating layer before calcination. After been sintered at 880 °C for 5 h, the sample shows Li{sub 2}MnO{sub 3} crystalline surface, as well as superior electrochemical performance. - Highlights: • Li{sub 2}MnO{sub 3}-coated LiNi{sub 0.5}Co{sub 0.2}Mn{sub 0.3}O{sub 2} is prepared by sol–gel method. • Neutral pH environment can protect NMC from damaging during the coating process. • Li{sub 2}MnO{sub 3} coating enhances the pristine at high cyclability and rate properties. • Suitable Li{sub 2}MnO{sub 3} modification results

Amorphous surface layer versus transient amorphous precursor phase in bone - A case study investigated by solid-state NMR spectroscopy.

Science.gov (United States)

Von Euw, Stanislas; Ajili, Widad; Chan-Chang, Tsou-Hsi-Camille; Delices, Annette; Laurent, Guillaume; Babonneau, Florence; Nassif, Nadine; Azaïs, Thierry

2017-09-01

The presence of an amorphous surface layer that coats a crystalline core has been proposed for many biominerals, including bone mineral. In parallel, transient amorphous precursor phases have been proposed in various biomineralization processes, including bone biomineralization. Here we propose a methodology to investigate the origin of these amorphous environments taking the bone tissue as a key example. This study relies on the investigation of a bone tissue sample and its comparison with synthetic calcium phosphate samples, including a stoichiometric apatite, an amorphous calcium phosphate sample, and two different biomimetic apatites. To reveal if the amorphous environments in bone originate from an amorphous surface layer or a transient amorphous precursor phase, a combined solid-state nuclear magnetic resonance (NMR) experiment has been used. The latter consists of a double cross polarization 1 H→ 31 P→ 1 H pulse sequence followed by a 1 H magnetization exchange pulse sequence. The presence of an amorphous surface layer has been investigated through the study of the biomimetic apatites; while the presence of a transient amorphous precursor phase in the form of amorphous calcium phosphate particles has been mimicked with the help of a physical mixture of stoichiometric apatite and amorphous calcium phosphate. The NMR results show that the amorphous and the crystalline environments detected in our bone tissue sample belong to the same particle. The presence of an amorphous surface layer that coats the apatitic core of bone apatite particles has been unambiguously confirmed, and it is certain that this amorphous surface layer has strong implication on bone tissue biogenesis and regeneration. Questions still persist on the structural organization of bone and biomimetic apatites. The existing model proposes a core/shell structure, with an amorphous surface layer coating a crystalline bulk. The accuracy of this model is still debated because amorphous calcium

In-Service Evaluation of HVOF Coated Main Landing Gear on Navy P-3 Aircraft

Science.gov (United States)

Devereaux, jon L.; Forrest, Clint

2008-01-01

Due to the environmental and health concerns with Electroplated Hard Chrome (EHC), the Hard Chrome Alternatives Team (HCAT) has been working to provide an alternative wear coating for EHC. The US Navy selected Tungsten-Carbide Cobalt (WC- 17Co) High Velocity Oxy-Fuel (HVOF) thermal spray coating for this purpose and completed service evaluations on select aircraft components to support the HCAT charter in identifying an alternative wear coating for chrome plating. Other benefits of WC-Co thermal spray coatings over EHC are enhanced corrosion resistance, improved durability, and exceptional wear properties. As part of the HCAT charter and to evaluate HVOF coatings on operational Navy components, the P-3 aircraft was selected for a service evaluation to determine the coating durability as compared to chrome plating. In April 1999, a VP-30 P-3 aircraft was outfitted with a right-hand Main Landing Gear (MLG) shock strut coated with WCCo HYOF thermal spray applied to the piston barrel and four axle journals. The HVOF coating on the piston barrel and axle journals was applied by Southwest United Industries, Inc. This HVOF coated strut assembly has since completed 6,378 landings. Teardown analysis .for this WC-Co HVOF coated MLG asset is significant in assessing the durability of this wear coating in service relative to EHC and to substantiate Life Cycle Cost (LCC) data to support a retrograde transition from EHC to HVOF thermal spray coatings. Findings from this teardown analysis may also benefit future transitions to HVOF thermal spray coatings by identifying enhancements to finishing techniques, mating bearing and liner material improvements, improved seal materials, and improvements in HVOF coating selection.

Development of cube textured Ni-W alloy substrates used for coated conductors

DEFF Research Database (Denmark)

Suo, Hongli; Ma, Lin; Gao, Mangmang

2014-01-01

It is considered as a challenge for RABiTS route to get cube textured Ni-W alloy substrates with high mechanical and magnetic properties for coated conductors. The works of our group in recent years are summarized about different Ni-W substrates with high W content and composite tapes made by RABiTS...

Spectral evidence for amorphous silicates in least-processed CO meteorites and their parent bodies

Science.gov (United States)

McAdam, Margaret M.; Sunshine, Jessica M.; Howard, Kieren T.; Alexander, Conel M.; McCoy, Timothy J.; Bus, Schelte J.

2018-05-01

Least-processed carbonaceous chondrites (carbonaceous chondrites that have experienced minimal aqueous alteration and thermal metamorphism) are characterized by their predominately amorphous iron-rich silicate interchondrule matrices and chondrule rims. This material is highly susceptible to destruction by the parent body processes of thermal metamorphism or aqueous alteration. The presence of abundant amorphous material in a meteorite indicates that the parent body, or at least a region of the parent body, experienced minimal processing since the time of accretion. The CO chemical group of carbonaceous chondrites has a significant number of these least-processed samples. We present visible/near-infrared and mid-infrared spectra of eight least-processed CO meteorites (petrologic type 3.0-3.1). In the visible/near-infrared, these COs are characterized by a broad weak feature that was first observed by Cloutis et al. (2012) to be at 1.3-μm and attributed to iron-rich amorphous silicate matrix materials. This feature is observed to be centered at 1.4-μm for terrestrially unweathered, least-processed CO meteorites. At mid-infrared wavelengths, a 21-μm feature, consistent with Si-O vibrations of amorphous materials and glasses, is also present. The spectral features of iron-rich amorphous silicate matrix are absent in both the near- and mid-infrared spectra of higher metamorphic grade COs because this material has recrystallized as crystalline olivine. Furthermore, spectra of least-processed primitive meteorites from other chemical groups (CRs, MET 00426 and QUE 99177, and C2-ungrouped Acfer 094), also exhibit a 21-μm feature. Thus, we conclude that the 1.4- and 21-μm features are characteristic of primitive least-processed meteorites from all chemical groups of carbonaceous chondrites. Finally, we present an IRTF + SPeX observation of asteroid (93) Minerva that has spectral similarities in the visible/near-infrared to the least-processed CO carbonaceous chondrites

Synthesis of TiC/W core–shell nanoparticles by precipitate-coating process

International Nuclear Information System (INIS)

Xia Min; Yan Qingzhi; Xu Lei; Zhu Lingxu; Guo Hongyan; Ge Changchun

2012-01-01

Graphical abstract: Well-dispersed titanium carbide/tungsten (TiC/W) core-shell nanoparticles with high-purity and uniform diameters were firstly synthesized by precipitate-coating process. Such unique process suggests a new method for preparing X/W (X refers the water-insoluble nanoparticles) core-shell nanoparticles with different cores. Abstract: Well-dispersed titanium carbide/tungsten (TiC/W) core–shell nanoparticles with high-purity and uniform diameters were firstly synthesized by precipitate-coating process. The as-synthesized nanoparticles were characterized by X-ray diffraction (XRD), Filed-emission scanning electron microscope (FESEM), Transmission electron microscopy (TEM), energy dispersive spectrum (EDS). Results revealed that the as-synthesized nanoparticles possess uniform diameters about 100 nm, and high purity. TEM and the corresponding FFT images demonstrate that TiC nanoparticles were well-encapsulated by W shells. Such unique process suggests a new method for preparing X/W (X refers the water-insoluble nanoparticles) core–shell nanoparticles with different cores.

Exchange bias and bistable magneto-resistance states in amorphous TbFeCo thin films

Energy Technology Data Exchange (ETDEWEB)

Li, Xiaopu, E-mail: xl6ba@virginia.edu; Ma, Chung T.; Poon, S. Joseph, E-mail: sjp9x@virginia.edu [Department of Physics, University of Virginia, Charlottesville, Virginia 22904 (United States); Lu, Jiwei [Department of Materials Science and Engineering, University of Virginia, Charlottesville, Virginia 22904 (United States); Devaraj, Arun [Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352 (United States); Spurgeon, Steven R.; Comes, Ryan B. [Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352 (United States)

2016-01-04

Amorphous TbFeCo thin films sputter deposited at room temperature on thermally oxidized Si substrate are found to exhibit strong perpendicular magnetic anisotropy. Atom probe tomography, scanning transmission electron microscopy, and energy dispersive X-ray spectroscopy mapping have revealed two nanoscale amorphous phases with different Tb atomic percentages distributed within the amorphous film. Exchange bias accompanied by bistable magneto-resistance states has been uncovered near room temperature by magnetization and magneto-transport measurements. The exchange anisotropy originates from the exchange interaction between the ferrimagnetic and ferromagnetic components corresponding to the two amorphous phases. This study provides a platform for exchange bias and magneto-resistance switching using single-layer amorphous ferrimagnetic thin films that require no epitaxial growth.

High performance W-AIN cermet solar coatings designed by modelling calculations and deposited by DC magnetron sputtering

Energy Technology Data Exchange (ETDEWEB)

Qi-Chu Zhang [The University of Sydney (Australia). School of Physics; Shen, Y.G. [City University of Hong Kong (Hong Kong). Department of Manufacturing Engineering and Engineering Management

2004-01-25

High solar performance W-AIN cermet solar coatings were designed using a numerical computer model and deposited experimentally. In the numerical calculations aluminium oxynitride (AlON) was used as ceramic component. The dielectric functions and then complex refractive index of W-AlON cermet materials were calculated using the Sheng's approximation. The layer thickness and W metal volume fraction were optimised to achieve maximum photo-thermal conversion efficiency for W-AlON cermet solar coatings on an Al reflector with a surface AlON ceramic anti-reflection layer. Optimisation calculations show that the W-AlON cermet solar coatings with two and three cermet layers have nearly identical solar absorptance, emittance and photo-thermal conversion efficiency that are much better than those for films with one cermet layer. The optimised calculated AlON/W-AlON/Al solar coating film with two cermet layers has a high solar absorptance of 0.953 and a low hemispherical emittance of 0.051 at 80{sup o}C for a concentration factor of 2. The AlN/W-AlN/Al solar selective coatings with two cermet layers were deposited using two metal target direct current magnetron sputtering technology. During the deposition of W-AlN cermet layer, both Al and W targets were run simultaneously in a gas mixture of argon and nitrogen. By substrate rotation a multi-sub-layer system consisting of alternating AlN ceramic and W metallic sub-layers was deposited that can be considered as a macro-homogeneous W-AlN cermet layer. A solar absorptance of 0.955 and nearly normal emittance of 0.056 at 80{sup o}C have been achieved for deposited W-AlN cermet solar coatings. (author)

SiO2-coated LiNi0.915Co0.075Al0.01O2 cathode material for rechargeable Li-ion batteries.

Science.gov (United States)

Zhou, Pengfei; Zhang, Zhen; Meng, Huanju; Lu, Yanying; Cao, Jun; Cheng, Fangyi; Tao, Zhanliang; Chen, Jun

2016-11-24

We reported a one-step dry coating of amorphous SiO 2 on spherical Ni-rich layered LiNi 0.915 Co 0.075 Al 0.01 O 2 (NCA) cathode materials. Combined characterization of XRD, EDS mapping, and TEM indicates that a SiO 2 layer with an average thickness of ∼50 nm was uniformly coated on the surface of NCA microspheres, without inducing any change of the phase structure and morphology. Electrochemical tests show that the 0.2 wt% SiO 2 -coated NCA material exhibits enhanced cyclability and rate properties, combining with better thermal stability compared with those of pristine NCA. For example, 0.2 wt% SiO 2 -coated NCA delivers a high specific capacity of 181.3 mA h g -1 with a capacity retention of 90.7% after 50 cycles at 1 C rate and 25 °C. Moreover, the capacity retention of this composite at 60 °C is 12.5% higher than that of pristine NCA at 1 C rate after 50 cycles. The effects of SiO 2 coating on the electrochemical performance of NCA are investigated by EIS, CV, and DSC tests, the improved performance is attributed to the surface coating layer of amorphous SiO 2 , which effectively suppresses side reactions between NCA and electrolytes, decreases the SEI layer resistance, and retards the growth of charge-transfer resistance, thus enhancing structural and cycling stability of NCA.

Amorphization of Ge and InP studied using nuclear hyperfine methods

International Nuclear Information System (INIS)

Byrne, A.P.; Bezakova, E.; Glover, C.J.; Ridgway, M.C.

1999-01-01

The ion beam amorphization of InP and Ge has been studied using the Perturbed Angular Correlation (PAC) technique. Semiconductor samples were preimplanted with the radioisotope 111 In using a direct production-recoil implantation method and beams from the ANU Heavy-ion Facility. Following annealing samples were amorphized using Ge beams with doses between 2 x 10 12 ion/cm 2 and 5000 x 10 12 ion/cm 2 . For InP the PAC spectra identified three distinct regimes, crystalline, disordered and amorphous environments, with a smooth transition observed as a function of dose. The dose dependence of the relative fractions of the individual probe environments has been determined. A direct amorphization process consistent with the overlap model was quantified and evidence for a second amorphization process via the overlap of disordered regions was observed. The PAC method compares favorably with other methods used in its ability to differentiate changes at high dose. The results for InP will be compared with those in Ge. The implantation method will be discussed, as will developments in the establishment of a dedicated facility for the implantation of radioisotopes

Iron binary and ternary coatings with molybdenum and tungsten

Energy Technology Data Exchange (ETDEWEB)

Yar-Mukhamedova, Gulmira, E-mail: gulmira-alma-ata@mail.ru [Institute Experimental and Theoretical Physics Al-Farabi Kazakh National University, 050038, Al-Farabi av., 71, Almaty (Kazakhstan); Ved, Maryna; Sakhnenko, Nikolay; Karakurkchi, Anna; Yermolenko, Iryna [National Technical University “Kharkov Polytechnic Institute”, Kharkov (Ukraine)

2016-10-15

Highlights: • High quality coatings of double Fe-Mo and ternary Fe-Mo-W electrolytic alloys can be produced both in a dc and a pulsed mode. • Application of unipolar pulsed current allows receiving an increased content of the alloying components and their more uniform distribution over the surface. • It is established that Fe-Mo and Fe-Mo-W coatings have an amorphous structure and exhibit improved corrosion resistance and microhardness as compared with the steel substrate due to the inclusion molybdenum and tungsten. - Abstract: Electrodeposition of Fe-Mo-W and Fe-Mo layers from a citrate solution containing iron(III) on steel and iron substrates is compared. The utilization of iron(III) compounds significantly improved the electrolyte stability eliminating side anodic redox reactions. The influence of concentration ratios and electrodeposition mode on quality, chemical composition, and functional properties of the alloys is determined. It has been found that alloys deposited in pulse mode have more uniform surface morphology and chemical composition and contain less impurities. Improvement in physical and mechanical properties as well as corrosion resistance of Fe-Mo and Fe-Mo-W deposits when compared with main alloy forming metals is driven by alloying components chemical passivity as well as by alloys amorphous structure. Indicated deposits can be considered promising materials in surface hardening technologies and repair of worn out items.

Effect of Heat Treatment on the Microstructure and Properties of HVOF-Sprayed Co-Cr-W Coating

Czech Academy of Sciences Publication Activity Database

Houdková, Š.; Smazalová, E.; Pala, Zdeněk

2016-01-01

Roč. 25, č. 3 (2016), s. 546-557 ISSN 1059-9630 Institutional support: RVO:61389021 Keywords : ASTM * G-65ASTM * Co-Cr-W * heat treatment * HVOF * Stellite 6 * wear Subject RIV: JK - Corrosion ; Surface Treatment of Materials Impact factor: 1.488, year: 2016

High-Performance Corrosion-Resistant Materials: Iron-Based Amorphous-Metal Thermal-Spray Coatings: SAM HPCRM Program ? FY04 Annual Report ? Rev. 0 - DARPA DSO & DOE OCRWM Co-Sponsored Advanced Materials Program

Energy Technology Data Exchange (ETDEWEB)

Farmer, J; Haslam, J; Wong, F; Ji, S; Day, S; Branagan, D; Marshall, M; Meacham, B; Buffa, E; Blue, C; Rivard, J; Beardsley, M; Buffa, E; Blue, C; Rivard, J; Beardsley, M; Weaver, D; Aprigliano, L; Kohler, L; Bayles, R; Lemieux, E; Wolejsza, T; Martin, F; Yang, N; Lucadamo, G; Perepezko, J; Hildal, K; Kaufman, L; Heuer, A; Ernst, F; Michal, G; Kahn, H; Lavernia, E

2007-09-19

The multi-institutional High Performance Corrosion Resistant Materials (HPCRM) Team is cosponsored by the Defense Advanced Projects Agency (DARPA) Defense Science Office (DSO) and the Department of Energy (DOE) Office of Civilian Radioactive Waste Management (OCRWM), and has developed new corrosion-resistant, iron-based amorphous metals that can be applied as coatings with advanced thermal spray technology. Two compositions have corrosion resistance superior to wrought nickel-based Alloy C-22 (UNS No. N06022) in very aggressive environments, including concentrated calcium-chloride brines at elevated temperature. Corrosion costs the Department of Defense billions of dollars every year, with an immense quantity of material in various structures undergoing corrosion. For example, in addition to fluid and seawater piping, ballast tanks, and propulsions systems, approximately 345 million square feet of structure aboard naval ships and crafts require costly corrosion control measures. The use of advanced corrosion-resistant materials to prevent the continuous degradation of this massive surface area would be extremely beneficial. The Fe-based corrosion-resistant, amorphous-metal coatings under development may prove of importance for applications on ships. Such coatings could be used as an 'integral drip shield' on spent fuel containers, as well as protective coatings that could be applied over welds, thereby preventing exposure to environments that might cause stress corrosion cracking. In the future, such new high-performance iron-based materials could be substituted for more-expensive nickel-based alloys, thereby enabling a reduction in the $58-billion life cycle cost for the long-term storage of the Nation's spent nuclear fuel by tens of percent.

Substrate temperature influence on the trombogenicity in amorphous carbon nitride thin coatings

Energy Technology Data Exchange (ETDEWEB)

Galeano-Osorio, D.S.; Vargas, S.; Lopez-Cordoba, L.M.; Ospina, R. [Laboratorio de Fisica del Plasma, Universidad Nacional de Colombia Sede Manizales, Km. 9 via al Magdalena, Manizales (Colombia); Restrepo-Parra, E., E-mail: erestrepopa@unal.edu.co [Laboratorio de Fisica del Plasma, Universidad Nacional de Colombia Sede Manizales, Km. 9 via al Magdalena, Manizales (Colombia); Arango, P.J. [Laboratorio de Fisica del Plasma, Universidad Nacional de Colombia Sede Manizales, Km. 9 via al Magdalena, Manizales (Colombia)

2010-10-01

Carbon nitride thin films were obtained through plasma assisted physical vapor deposition technique by pulsed arc, varying the substrate temperature and investigating the influence of this parameter on the films hemocompatibility. For obtaining approaches of blood compatibility, environmental scanning electron microscopy (ESEM) was used in order to study the platelets adherence and their morphology. Moreover, the elemental chemical composition was determined by using energy dispersive spectroscopy (EDS), finding C, N and O. The coatings hemocompatibility was evaluated by in vitro thrombogenicity test, whose results were correlated with the microstructure and roughness of the films obtained. During the films growth process, the substrate temperature was varied, obtaining coatings under different temperatures, room temperature (T{sub room}), 100 deg. C, 150 deg. C and 200 deg. C. Parameters as interelectrodic distance, voltage, work pressure and number of discharges, were remained constant. By EDS, carbon and nitrogen were found in the films. Visible Raman spectroscopy was used, and it revealed an amorphous lattice, with graphitic process as the substrate temperature was increased. However, at a critical temperature of 150 deg. C, this tendency was broken, and the film became more amorphous. This film showed the lowest roughness, 2 {+-} 1 nm. This last characteristic favored the films hemocompatibility. Also, it was demonstrated that the blood compatibility of carbon nitride films obtained were affected by the I{sub D}/I{sub G} or sp{sup 3}/sp{sup 2} ratio and not by the absolute sp{sup 3} or sp{sup 2} concentration.

Carbon Nitrogen Co-Doped P25: Parameter Study on Photodegradation of Reactive Red 4

Directory of Open Access Journals (Sweden)

Azami M. S.

2016-01-01

Full Text Available Photocatalytic degradation rate of reactive red 4 (RR4 using carbon coated nitrogen doped TiO2 (C N co-doped TiO2 in photocatalysis process is main goal on this research. The main operating the parameters such as effect of initial dye concentration, catalyst loading, aeration flow rate and initial pH on degradation of RR4 under 45 W fluorescent lamp was investigated. photocatalytic activity of RR4 dye decreased with increasing RR4 dye concentration. The optimum loading is around 0.04 g and optimum aeration rate is about 25 mL min-1 of C N co-doped TiO2. Effect of pH was conducted based on the optimum loading and conclude that the photocatalytic degradation of RR4 became faster at pH 2 - 7. For the future work, the modification of doping with others element like non-metal or metal with C N co-doped TiO2 can be enhanced toward the higher efficieny of photodegradation under visible light. Moreover, the immobilized technique can be used in future to overcome the difficulty of filtration on suspension.

Computational Evaluation of Amorphous Carbon Coating for Durable Silicon Anodes for Lithium-Ion Batteries

Science.gov (United States)

Hwang, Jeongwoon; Ihm, Jisoon; Lee, Kwang-Ryeol; Kim, Seungchul

2015-01-01

We investigate the structural, mechanical, and electronic properties of graphite-like amorphous carbon coating on bulky silicon to examine whether it can improve the durability of the silicon anodes of lithium-ion batteries using molecular dynamics simulations and ab-initio electronic structure calculations. Structural models of carbon coating are constructed using molecular dynamics simulations of atomic carbon deposition with low incident energies (1–16 eV). As the incident energy decreases, the ratio of sp2 carbons increases, that of sp3 decreases, and the carbon films become more porous. The films prepared with very low incident energy contain lithium-ion conducting channels. Also, those films are electrically conductive to supplement the poor conductivity of silicon and can restore their structure after large deformation to accommodate the volume change during the operations. As a result of this study, we suggest that graphite-like porous carbon coating on silicon will extend the lifetime of the silicon anodes of lithium-ion batteries. PMID:28347087

Computational Evaluation of Amorphous Carbon Coating for Durable Silicon Anodes for Lithium-Ion Batteries

Directory of Open Access Journals (Sweden)

Jeongwoon Hwang

2015-10-01

Full Text Available We investigate the structural, mechanical, and electronic properties of graphite-like amorphous carbon coating on bulky silicon to examine whether it can improve the durability of the silicon anodes of lithium-ion batteries using molecular dynamics simulations and ab-initio electronic structure calculations. Structural models of carbon coating are constructed using molecular dynamics simulations of atomic carbon deposition with low incident energies (1–16 eV. As the incident energy decreases, the ratio of sp2 carbons increases, that of sp3 decreases, and the carbon films become more porous. The films prepared with very low incident energy contain lithium-ion conducting channels. Also, those films are electrically conductive to supplement the poor conductivity of silicon and can restore their structure after large deformation to accommodate the volume change during the operations. As a result of this study, we suggest that graphite-like porous carbon coating on silicon will extend the lifetime of the silicon anodes of lithium-ion batteries.

Y2O3-W Continuous Graded Materials by Co-sedimentation

Directory of Open Access Journals (Sweden)

WANG Shi-yang

2017-09-01

Full Text Available The raw Y2O3 powder was classified and graded based on modified co-sedimentation mathematical model,using the size distribution of W particles as the known condition. Y2O3-W continuous graded materials with the composition distribution index P values of 1.0, 0.7, 0.3 and 0.1 were prepared by co-sedimentation and hot-pressing. The results show that the Y2O3 powder consistent with the design requirements can be obtained by graduation method. The gradient continuity of materials can be verified by microstructure observation and hardness testing.

Effects of amorphous silica coating on cerium oxide nanoparticles induced pulmonary responses

International Nuclear Information System (INIS)

Ma, Jane; Mercer, Robert R.; Barger, Mark; Schwegler-Berry, Diane; Cohen, Joel M.; Demokritou, Philip; Castranova, Vincent

2015-01-01

Recently cerium compounds have been used in a variety of consumer products, including diesel fuel additives, to increase fuel combustion efficiency and decrease diesel soot emissions. However, cerium oxide (CeO 2 ) nanoparticles have been detected in the exhaust, which raises a health concern. Previous studies have shown that exposure of rats to nanoscale CeO 2 by intratracheal instillation (IT) induces sustained pulmonary inflammation and fibrosis. In the present study, male Sprague–Dawley rats were exposed to CeO 2 or CeO 2 coated with a nano layer of amorphous SiO 2 (aSiO 2 /CeO 2 ) by a single IT and sacrificed at various times post-exposure to assess potential protective effects of the aSiO 2 coating. The first acellular bronchoalveolar lavage (BAL) fluid and BAL cells were collected and analyzed from all exposed animals. At the low dose (0.15 mg/kg), CeO 2 but not aSiO 2 /CeO 2 exposure induced inflammation. However, at the higher doses, both particles induced a dose-related inflammation, cytotoxicity, inflammatory cytokines, matrix metalloproteinase (MMP)-9, and tissue inhibitor of MMP at 1 day post-exposure. Morphological analysis of lung showed an increased inflammation, surfactant and collagen fibers after CeO 2 (high dose at 3.5 mg/kg) treatment at 28 days post-exposure. aSiO 2 coating significantly reduced CeO 2 -induced inflammatory responses in the airspace and appeared to attenuate phospholipidosis and fibrosis. Energy dispersive X-ray spectroscopy analysis showed Ce and phosphorous (P) in all particle-exposed lungs, whereas Si was only detected in aSiO 2 /CeO 2 -exposed lungs up to 3 days after exposure, suggesting that aSiO 2 dissolved off the CeO 2 core, and some of the CeO 2 was transformed to CePO 4 with time. These results demonstrate that aSiO 2 coating reduce CeO 2 -induced inflammation, phospholipidosis and fibrosis. - Highlights: • Both CeO 2 and aSiO 2 /CeO 2 particles were detected in the respective particle-exposed lungs. • The

Hydrogenated amorphous silicon coatings may modulate gingival cell response

Science.gov (United States)

Mussano, F.; Genova, T.; Laurenti, M.; Munaron, L.; Pirri, C. F.; Rivolo, P.; Carossa, S.; Mandracci, P.

2018-04-01

Silicon-based materials present a high potential for dental implant applications, since silicon has been proven necessary for the correct bone formation in animals and humans. Notably, the addition of silicon is effective to enhance the bioactivity of hydroxyapatite and other biomaterials. The present work aims to expand the knowledge of the role exerted by hydrogen in the biological interaction of silicon-based materials, comparing two hydrogenated amorphous silicon coatings, with different hydrogen content, as means to enhance soft tissue cell adhesion. To accomplish this task, the films were produced by plasma enhanced chemical vapor deposition (PECVD) on titanium substrates and their surface composition and hydrogen content were analyzed by means of X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared spectrophotometry (FTIR) respectively. The surface energy and roughness were measured through optical contact angle analysis (OCA) and high-resolution mechanical profilometry respectively. Coated surfaces showed a slightly lower roughness, compared to bare titanium samples, regardless of the hydrogen content. The early cell responses of human keratinocytes and fibroblasts were tested on the above mentioned surface modifications, in terms of cell adhesion, viability and morphometrical assessment. Films with lower hydrogen content were endowed with a surface energy comparable to the titanium surfaces. Films with higher hydrogen incorporation displayed a lower surface oxidation and a considerably lower surface energy, compared to the less hydrogenated samples. As regards mean cell area and focal adhesion density, both a-Si coatings influenced fibroblasts, but had no significant effects on keratinocytes. On the contrary, hydrogen-rich films increased manifolds the adhesion and viability of keratinocytes, but not of fibroblasts, suggesting a selective biological effect on these cells.

Confinement of Amorphous Lactose in Pores Formed Upon Co-Spray Drying With Nanoparticles.

Science.gov (United States)

Hellrup, Joel; Mahlin, Denny

2017-01-01

This study aims at investigating factors influencing humidity-induced recrystallization of amorphous lactose, produced by co-spray drying with particles of cellulose nanocrystals or sodium montmorillonite. In particular, the focus is on how the nanoparticle shape and surface properties influence the nanometer to micrometer length scale nanofiller arrangement in the nanocomposites and how the arrangements influence the mechanisms involved in the inhibition of the amorphous to crystalline transition. The nanocomposites were produced by co-spray drying. Solid-state transformations were analyzed at 60%-94% relative humidity using X-ray powder diffraction, microcalorimetry, and light microscopy. The recrystallization rate constant for the lactose/cellulose nanocrystals and lactose/sodium montmorillonite nanocomposites was lowered at nanofiller contents higher than 60% and was stable for months at 80% nanofiller. The most likely explanation to these results is spontaneous formations of mesoporous particle networks that the lactose is confined upon co-spray drying at high filler content. Compartmentalization and rigidification of the amorphous lactose proved to be less important mechanisms involved in the stabilization of lactose in the nanocomposites. Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

Corrosion Resistance Of Electroless Ni-P/Cu/Ni-P Multilayer Coatings

Directory of Open Access Journals (Sweden)

Zhao G.L.

2015-06-01

Full Text Available Ni-P/Cu/Ni-P multilayer coatings were prepared by deposition of Cu layer between two Ni–P layers. The Cu layer was deposited by metal displacement reaction between Cu2+ and Fe atoms. Corrosion behavior of single-layer Ni-P coatings, double-layer Ni-P/Cu coatings, and three-layer Ni-P/Cu/Ni-P coatings were investigated by electrochemical tests in 3.5% NaCl solution. The three-layer coatings exhibited more positive Ecorr and decreased Icorr compared with conventional single-layer Ni-P coatings, which indicated an improved corrosion resistance. The polarization curves of the three-layer coatings were characterized by two passive regions. The improved corrosion resistance was not only attributed to the function of the blocked pores of Cu. The Cu interlayer also acted as a sacrificial layer instead of a barrier in the coatings, which altered the corrosion mechanism and further improved the corrosion resistance of the coatings.

Exclusive Hydrogen Generation by Electrocatalysts Coated with an Amorphous Chromium-Based Layer Achieving Efficient Overall Water Splitting

KAUST Repository

Qureshi, Muhammad

2017-08-08

Successful conversion of renewable energy to useful chemicals requires efficient devices that can electrocatalyze or photocatalyze redox reactions, e.g., overall water splitting. Excellent electrocatalysts for the hydrogen evolution reaction (HER), such as Pt, can also cause other side-reactions, including the water-forming back-reaction from H2 and O2 products. A Cr-based amorphous layer coated on catalysts can work as a successful surface modifier that avoids the back-reaction, but its capabilities and limitations toward other species have not been studied. Herein, we investigated the Cr-based layer on Pt from perspectives of both electrocatalysis and photocatalysis using redox-active molecules/ions (O2, ferricyanide, IO3–, S2O82–, H2O2, and CO gas). Our systematic study revealed that utilization of the Cr-based layer realized an exclusive cathodic reaction only to HER, even in the presence of the aforementioned reactive species, suggesting that Cr-based layers work as membranes, as well as corrosion and poison inhibition layers. However, the Cr-based layer experienced self-oxidation and dissolved into the aqueous phase when a strong oxidizing agent or low pH was present. Presented herein are fundamental and critical aspects of the Cr-based modifier, which is essential for the successful and practical development of solar fuel production systems.

Exclusive Hydrogen Generation by Electrocatalysts Coated with an Amorphous Chromium-Based Layer Achieving Efficient Overall Water Splitting

KAUST Repository

Qureshi, Muhammad; Shinagawa, Tatsuya; Tsiapis, Nikolaos; Takanabe, Kazuhiro

2017-01-01

Successful conversion of renewable energy to useful chemicals requires efficient devices that can electrocatalyze or photocatalyze redox reactions, e.g., overall water splitting. Excellent electrocatalysts for the hydrogen evolution reaction (HER), such as Pt, can also cause other side-reactions, including the water-forming back-reaction from H2 and O2 products. A Cr-based amorphous layer coated on catalysts can work as a successful surface modifier that avoids the back-reaction, but its capabilities and limitations toward other species have not been studied. Herein, we investigated the Cr-based layer on Pt from perspectives of both electrocatalysis and photocatalysis using redox-active molecules/ions (O2, ferricyanide, IO3–, S2O82–, H2O2, and CO gas). Our systematic study revealed that utilization of the Cr-based layer realized an exclusive cathodic reaction only to HER, even in the presence of the aforementioned reactive species, suggesting that Cr-based layers work as membranes, as well as corrosion and poison inhibition layers. However, the Cr-based layer experienced self-oxidation and dissolved into the aqueous phase when a strong oxidizing agent or low pH was present. Presented herein are fundamental and critical aspects of the Cr-based modifier, which is essential for the successful and practical development of solar fuel production systems.

High performance W-AlN cermet solar coatings designed by modelling calculations and deposited by DC magnetron sputtering

Energy Technology Data Exchange (ETDEWEB)

Zhang, Qi-Chu [School of Physics, The University of Sydney, Sydney, NSW 2006 (Australia); Shen, Y.G. [Department of Manufacturing Engineering and Engineering Management, City University of Hong Kong (Hong Kong)

2004-01-25

High solar performance W-AlN cermet solar coatings were designed using a numerical computer model and deposited experimentally. In the numerical calculations aluminium oxynitride (AlON) was used as ceramic component. The dielectric function and then complex refractive index of W-AlON cermet materials were calculated using the Sheng's approximation. The layer thickness and W metal volume fraction were optimised to achieve maximum photo-thermal conversion efficiency for W-AlON cermet solar coatings on an Al reflector with a surface AlON ceramic anti-reflection layer. Optimisation calculations show that the W-AlON cermet solar coatings with two and three cermet layers have nearly identical solar absorptance, emittance and photo-thermal conversion efficiency that are much better than those for films with one cermet layer. The optimised calculated AlON/W-AlON/Al solar coating film with two cermet layers has a high solar absorptance of 0.953 and a low hemispherical emittance of 0.051 at 80C for a concentration factor of 2. The AlN/W-AlN/Al solar selective coatings with two cermet layers were deposited using two metal target direct current magnetron sputtering technology. During the deposition of W-AlN cermet layer, both Al and W targets were run simultaneously in a gas mixture of argon and nitrogen. By substrate rotation a multi-sub-layer system consisting of alternating AlN ceramic and W metallic sub-layers was deposited that can be considered as a macro-homogeneous W-AlN cermet layer. A solar absorptance of 0.955 and nearly normal emittance of 0.056 at 80C have been achieved for deposited W-AlN cermet solar coatings.

Effect of W Contents on Martensitic Transformation and Shape Memory Effect in Co-Al-W Alloys

Science.gov (United States)

Yang, X.; Qian, B. N.; Peng, H. B.; Wu, B. J.; Wen, Y. H.

2018-04-01

To clarify the effect of W contents on the shape memory effect (SME) in the Co-Al alloys and its influencing mechanism, the SME, martensitic transformation, and deformation behavior were studied in the Co-7Al-xW ( x = 0, 4, 6, 9 wt pct) alloys. The results showed that the additions of W all deteriorated the SME in Co-7Al alloy when deformed at room temperature. However, when deformed in liquid nitrogen, the SME in Co-7Al alloy could be remarkably improved from 43 to 78 pct after the addition of 4 pct W, above which the SME decreased rapidly with the increase of W content although the yield strength of the parent phase rose due to the solution strengthening of W. The deterioration in SME induced by the excessive addition of W could be ascribed to its resulting significant drop of the start temperature of martensitic transformation.

Bias voltage dependence of magnetic tunnel junctions comprising amorphous ferromagnetic CoFeSiB layer with double barriers

International Nuclear Information System (INIS)

Yim, H.I.; Lee, S.Y.; Hwang, J.Y.; Rhee, J.R.; Chun, B.S.; Wang, K.L.; Kim, Y.K.; Kim, T.W.; Lee, S.S.; Hwang, D.G.

2008-01-01

Double-barrier magnetic tunnel junctions (DMTJs) with and without an amorphous ferromagnetic material such as CoFeSiB 10, CoFe 5/CoFeSiB 5, and CoFe 10 (nm) were prepared and compared to investigate the bias voltage dependence of the tunneling magnetoresistance (TMR) ratio. Typical DMTJ structures were Ta 45/Ru 9.5/IrMn 10/CoFe 7/AlO x /free layer 10/AlO x /CoFe 7/IrMn 10/Ru 60 (in nanometers). The interlayer coupling field and the normalized TMR ratios at the applied voltages of +0.4 and -0.4 V of the amorphous CoFeSiB free-layer DMTJ offer lower and higher values than that of the polycrystalline CoFe free-layer DMTJ, respectively. An amorphous ferromagnetic CoFeSiB layer improves the interface roughness of the free layer/tunnel barrier and, as a result, the interlayer coupling field and bias voltage dependence of the TMR ratio are suppressed at a given voltage. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Inert-Gas Condensed Co-W Nanoclusters: Formation, Structure and Magnetic Properties

Science.gov (United States)

Golkar-Fard, Farhad Reza

Rare-earth permanent magnets are used extensively in numerous technical applications, e.g. wind turbines, audio speakers, and hybrid/electric vehicles. The demand and production of rare-earth permanent magnets in the world has in the past decades increased significantly. However, the decrease in export of rare-earth elements from China in recent time has led to a renewed interest in developing rare-earth free permanent magnets. Elements such as Fe and Co have potential, due to their high magnetization, to be used as hosts in rare-earth free permanent magnets but a major challenge is to increase their magnetocrystalline anisotropy constant, K1, which largely drives the coercivity. Theoretical calculations indicate that dissolving the 5d transition metal W in Fe or Co increases the magnetocrystalline anisotropy. The challenge, though, is in creating a solid solution in hcp Co or bcc Fe, which under equilibrium conditions have negligible solubility. In this dissertation, the formation, structure, and magnetic properties of sub-10 nm Co-W clusters with W content ranging from 4 to 24 atomic percent were studied. Co-W alloy clusters with extended solubility of W in hcp Co were produced by inert gas condensation. The different processing conditions such as the cooling scheme and sputtering power were found to control the structural state of the as-deposited Co-W clusters. For clusters formed in the water-cooled formation chamber, the mean size and the fraction crystalline clusters increased with increasing power, while the fraction of crystalline clusters formed in the liquid nitrogen-cooled formation chamber was not as affected by the sputtering power. For the low W content clusters, the structural characterization revealed clusters predominantly single crystalline hcp Co(W) structure, a significant extension of W solubility when compared to the equilibrium solubility, but fcc Co(W) and Co3W structures were observed in very small and large clusters, respectively. At high

Perpendicular magnetic anisotropy of amorphous ferromagnetic CoSiB/[Pt,Au] multilayer

International Nuclear Information System (INIS)

Jeong, S.; Yim, H. I.

2012-01-01

Perpendicular magnetic anisotropy is being widely studied as a possible candidate for a high density spin-transfer torque magnetic random access memory. The key issues of a high-density spin-transfer torque magnetic random access memory are decreasing the switching current and the high thermal stability. In order to solve these problems, two approaches are suggested: One is the development a new amorphous ferromagnetic material as a pinned layer for a multilayer with a low saturated magnetization (M s ) value because of the interface roughness between the two layers. The other is a search for the most suitable materials with high perpendicular magnetic anisotropy in order to have high thermal stability. In this work, we present an amorphous ferromagnetic Co 75 Si 15 B 10 material and compare the magnetic properties of a [CoSiB (0.3, 0.4, 0.5 nm)/Pt (1.4 nm)] 5 multilayer and new combinations [CoSiB (0.3, 0.4, 0.5 nm)/Au (1.5 nm)] 5 .

Amorphous TiO2 Shells: A Vital Elastic Buffering Layer on Silicon Nanoparticles for High-Performance and Safe Lithium Storage.

Science.gov (United States)

Yang, Jianping; Wang, Yunxiao; Li, Wei; Wang, Lianjun; Fan, Yuchi; Jiang, Wan; Luo, Wei; Wang, Yang; Kong, Biao; Selomulya, Cordelia; Liu, Hua Kun; Dou, Shi Xue; Zhao, Dongyuan

2017-12-01

Smart surface coatings of silicon (Si) nanoparticles are shown to be good examples for dramatically improving the cyclability of lithium-ion batteries. Most coating materials, however, face significant challenges, including a low initial Coulombic efficiency, tedious processing, and safety assessment. In this study, a facile sol-gel strategy is demonstrated to synthesize commercial Si nanoparticles encapsulated by amorphous titanium oxide (TiO 2 ), with core-shell structures, which show greatly superior electrochemical performance and high-safety lithium storage. The amorphous TiO 2 shell (≈3 nm) shows elastic behavior during lithium discharging and charging processes, maintaining high structural integrity. Interestingly, it is found that the amorphous TiO 2 shells offer superior buffering properties compared to crystalline TiO 2 layers for unprecedented cycling stability. Moreover, accelerating rate calorimetry testing reveals that the TiO 2 -encapsulated Si nanoparticles are safer than conventional carbon-coated Si-based anodes. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Production of Organic Grain Coatings by Surface-Mediated Reactions and the Consequences of This Process for Meteoritic Constituents

Science.gov (United States)

Nuth, Joseph A., III; Johnson, Natasha M.

2011-01-01

When hydrogen, nitrogen and CO are exposed to amorphous iron silicate surfaces at temperatures between 500 - 900K, a carbonaceous coating forms via Fischer-Tropsch type reactions. Under normal circumstances such a catalytic coating would impede or stop further reaction. However, we find that this coating is a better catalyst than the amorphous iron silicates that initiate these reactions. The formation of a self-perpetuating catalytic coating on grain surfaces could explain the rich deposits of macromolecular carbon found in primitive meteorites and would imply that protostellar nebulae should be rich in organic material. Many more experiments are needed to understand this chemical system and its application to protostellar nebulae.

High-Performance Corrosion-Resistant Materials: Iron-Based Amorphous-Metal Thermal-Spray Coatings: SAM HPCRM Program ? FY04 Annual Report ? Rev. 0 - DARPA DSO and DOE OCRWM Co-Sponsored Advanced Materials Program

International Nuclear Information System (INIS)

Farmer, J; Haslam, J; Wong, F; Ji, S; Day, S; Branagan, D; Marshall, M; Meacham, B; Buffa, E; Blue, C; Rivard, J; Beardsley, M; Buffa, E; Blue, C; Rivard, J; Beardsley, M; Weaver, D; Aprigliano, L; Kohler, L; Bayles, R; Lemieux, E; Wolejsza, T; Martin, F; Yang, N; Lucadamo, G; Perepezko, J; Hildal, K; Kaufman, L; Heuer, A; Ernst, F; Michal, G; Kahn, H; Lavernia, E

2007-01-01

The multi-institutional High Performance Corrosion Resistant Materials (HPCRM) Team is cosponsored by the Defense Advanced Projects Agency (DARPA) Defense Science Office (DSO) and the Department of Energy (DOE) Office of Civilian Radioactive Waste Management (OCRWM), and has developed new corrosion-resistant, iron-based amorphous metals that can be applied as coatings with advanced thermal spray technology. Two compositions have corrosion resistance superior to wrought nickel-based Alloy C-22 (UNS No. N06022) in very aggressive environments, including concentrated calcium-chloride brines at elevated temperature. Corrosion costs the Department of Defense billions of dollars every year, with an immense quantity of material in various structures undergoing corrosion. For example, in addition to fluid and seawater piping, ballast tanks, and propulsions systems, approximately 345 million square feet of structure aboard naval ships and crafts require costly corrosion control measures. The use of advanced corrosion-resistant materials to prevent the continuous degradation of this massive surface area would be extremely beneficial. The Fe-based corrosion-resistant, amorphous-metal coatings under development may prove of importance for applications on ships. Such coatings could be used as an 'integral drip shield' on spent fuel containers, as well as protective coatings that could be applied over welds, thereby preventing exposure to environments that might cause stress corrosion cracking. In the future, such new high-performance iron-based materials could be substituted for more-expensive nickel-based alloys, thereby enabling a reduction in the $58-billion life cycle cost for the long-term storage of the Nation's spent nuclear fuel by tens of percent

Microstructure Changes of ZrO{sub 2}/W/Mo Coating Layers on Graphite after Heat Treatment at 2100 ℃

Energy Technology Data Exchange (ETDEWEB)

Ahn, Gyu Baek; Choe, Kyeong Hwan; Cho, Gue Serb [Korea Institute of Industrial Technology, Incheon (Korea, Republic of); Kim, Sang Sub [Inha University, Incheon (Korea, Republic of)

2016-08-15

A tungsten coating was deposited onto a graphite substrate using the atmospheric plasma spraying (APS) technique. In order to increase the adhesion strength between the metallic tungsten(W) and graphite, a molybdenum (Mo) interlayer was pre-deposited onto the graphite surface by utilizing the APS technique. Also, after deposition of a APS-W coating, a zirconia (ZrO{sub 2}) was deposited onto the W coating layer. For the APS process, argon and helium were used as the plasma-forming gases, and argon was used as the shield gas to protect the plasma from oxidation. After the APS coating process, heat exposure treatment was performed at 2100 ℃ for 360 h within a sapphire single crystal-growing furnace in order to evaluate the thermal stability of the coatings. After heat treatment, the ZrO{sub 2}/W/Mo coating layers were bound with the graphite without any peeling off. The microvickers hardness of the APS-W coating layer was increased after heat treatment due to the formation of carbides. Also, carbide phases such as Mo{sub 2}C, WC, ZrC and Mo{sub 3}C{sub 2} were identified by XRD diffraction and EDS analysis, by analyzing the depths below the coating surface. It was considered that the Mo interlayer served as a good buffer layer between the APS-W coating and the graphite after the heat exposure treatment because the lattice structure of the molybdenum carbide was similar to that of the graphite.

Development of Anti-Insect Microencapsulated Polypropylene Films Using a Large Scale Film Coating System.

Science.gov (United States)

Song, Ah Young; Choi, Ha Young; Lee, Eun Song; Han, Jaejoon; Min, Sea C

2018-04-01

Films containing microencapsulated cinnamon oil (CO) were developed using a large-scale production system to protect against the Indian meal moth (Plodia interpunctella). CO at concentrations of 0%, 0.8%, or 1.7% (w/w ink mixture) was microencapsulated with polyvinyl alcohol. The microencapsulated CO emulsion was mixed with ink (47% or 59%, w/w) and thinner (20% or 25%, w/w) and coated on polypropylene (PP) films. The PP film was then laminated with a low-density polyethylene (LDPE) film on the coated side. The film with microencapsulated CO at 1.7% repelled P. interpunctella most effectively. Microencapsulation did not negatively affect insect repelling activity. The release rate of cinnamaldehyde, an active repellent, was lower when CO was microencapsulated than that in the absence of microencapsulation. Thermogravimetric analysis exhibited that microencapsulation prevented the volatilization of CO. The tensile strength, percentage elongation at break, elastic modulus, and water vapor permeability of the films indicated that microencapsulation did not affect the tensile and moisture barrier properties (P > 0.05). The results of this study suggest that effective films for the prevention of Indian meal moth invasion can be produced by the microencapsulation of CO using a large-scale film production system. Low-density polyethylene-laminated polypropylene films printed with ink incorporating microencapsulated cinnamon oil using a large-scale film production system effectively repelled Indian meal moth larvae. Without altering the tensile and moisture barrier properties of the film, microencapsulation resulted in the release of an active repellent for extended periods with a high thermal stability of cinnamon oil, enabling commercial film production at high temperatures. This anti-insect film system may have applications to other food-packaging films that use the same ink-printing platform. © 2018 Institute of Food Technologists®.

The effect of nickel electrodeposition on magnetic properties of CoFeSiB amorphous wire

International Nuclear Information System (INIS)

Atalay, F.E.

2004-01-01

Nickel films were electrodeposited on rapidly quenched amorphous wires from nitrate bath using a constant voltage. It was found that the pH of plating bath had a very strong effect on the formation of nickel films. The magnetic field, H, dependence of the impedance, of nickel plated (Co 0.94 Fe 0.06 ) 72.5 Si 12.5 B 15 wires have been investigated using a Hewlett-Packard 4294A impedance analyser with 42941A impedance probe. The best elecroplating condition and GMI response were obtained for the plated wire at pH 5 for 30 min plating time

Application of electroless Ni-P coating on magnesium alloy via CrO3/HF free titanate pretreatment

Science.gov (United States)

Rajabalizadeh, Z.; Seifzadeh, D.

2017-11-01

The titanate conversion coating was applied as CrO3/HF free pretreatment for the electroless Ni-P plating on AM60B magnesium alloy. The microscopic images revealed that the alloy surface was completely covered by a cracked conversion film after titanate pretreatment which was mainly composed of Mg(OH)2/MgO, MgF2, TiO2, SiO2, and Al2O3/Al(OH)3. The microscopic images also revealed that numerous Ni nucleation centers were formed over the titanate film after short electroless plating times. The nucleation centers were created not only on the cracked area but also over the whole pretreated surface due to the catalytic action of the titanate film. Also, uniform, dense, and defect-free Ni-P coating with fine structure was achieved after 3 h plating. The Ni-P coating showed mixed crystalline-amorphous structure due to its moderate phosphorus content. The results of two traditional corrosion monitoring methods indicated that the Ni-P coating significantly increases the corrosion resistance of the magnesium alloy. Moreover, Electrochemical Noise (EN) method was used as a non-polarized technique to study the corrosion behavior of the electroless coating at different immersion times. The results of the EN tests were clearly showed the localized nature of the corrosion process. Micro-hardness value of the magnesium alloy was remarkably enhanced after the electroless plating. Finally, suitable adhesion between the Ni-P coating and the magnesium alloy substrate was confirmed by thermal shock and pull-off-adhesion tests.

Hidroxyapatite Coating on CoCrMo Alloy Titanium Nitride Coated Using Biomimetic Method

International Nuclear Information System (INIS)

Charlena; Sukaryo, S.G.; Fajar, M.

2016-01-01

Bone implants is a way to cure broken bones which is being developed. The implants can be made of metals, ceramics and polymers. Metallic materials commonly used are titanium (Ti), stainless steel, and metal alloys. This study used Co-based alloys, i.e. CoCrMo coated with titanium nitride (TiN) which was then coated on hidroxyapatite (HAp). The HAp coating on the surface of CoCrMo alloy was done by biomimetic methods, first by soaking the metal alloys in simulated body fluid (SBF) solution for 18, 24, and 36 hours. The immersion in the SBF solution produced white coat on the surface of the metal alloy. The layers formed were analyzed by scanning electron microscope (SEM) and characterized by x-ray diffractometer (XRD). Based on the SEM results of 36 hours treatment, the morphology of apatite crystal formed fine grains. According to XRD result, there were HAp peaks at angles 2θ 31.86, 32.25, dan 39.48. However, there were also CaCO 3 peaks at angles 2θ 29.46, 36.04, and 46.79. It indicated the pure HAp is not yet formed. (paper)

Hidroxyapatite Coating on CoCrMo Alloy Titanium Nitride Coated Using Biomimetic Method

Science.gov (United States)

Charlena; Sukaryo, S. G.; Fajar, M.

2016-11-01

Bone implants is a way to cure broken bones which is being developed. The implants can be made of metals, ceramics and polymers. Metallic materials commonly used are titanium (Ti), stainless steel, and metal alloys. This study used Co-based alloys, i.e. CoCrMo coated with titanium nitride (TiN) which was then coated on hidroxyapatite (HAp). The HAp coating on the surface of CoCrMo alloy was done by biomimetic methods, first by soaking the metal alloys in simulated body fluid (SBF) solution for 18, 24, and 36 hours. The immersion in the SBF solution produced white coat on the surface of the metal alloy. The layers formed were analyzed by scanning electron microscope (SEM) and characterized by x-ray diffractometer (XRD). Based on the SEM results of 36 hours treatment, the morphology of apatite crystal formed fine grains. According to XRD result, there were HAp peaks at angles 2θ 31.86, 32.25, dan 39.48. However, there were also CaCO3 peaks at angles 2θ 29.46, 36.04, and 46.79. It indicated the pure HAp is not yet formed.

Highly hard yet toughened bcc-W coating by doping unexpectedly low B content

KAUST Repository

Yang, Lina; Zhang, Kan; Wen, Mao; Hou, Zhipeng; Gong, Chen; Liu, Xucheng; Hu, Chaoquan; Cui, Xiaoqiang; Zheng, Weitao

2017-01-01

of improved hardness (2 × larger than pure W) and superior toughness (higher crack formation threshold compared to pure W). We believe this is an innovative sight to design new generation of transition-metal-based multifunctional coatings. Besides, our results

Comparative study of electroless Co-Ni-P plating on Tencel fabric by Co0-based and Ni0-based activation for electromagnetic interference shielding

Science.gov (United States)

Bi, Siyi; Zhao, Hang; Hou, Lei; Lu, Yinxiang

2017-10-01

The primary objective of this research work was to develop high-performance conductive fabrics with desired electromagnetic interference (EMI) shielding effectiveness (SE), excellent durability and improved corrosion resistance. Such conductive fabrics were fabricated by combining an ultra-low-cost electroless plating method with an alkoxy silane self-assembly technology, which involved successive steps of modification, activation, Co-Ni-P coating deposition and 3-aminopropyltrimethoxysilane (APTMS) thin coatings assembling. Malic acid (MA) was selected to modify the pristine Tencel (TS) substrates, and the probably interaction mechanism was investigated by FT-IR measurement. Co0 and Ni0 nanoparticles (NPs) were used as the activators to initiate electroless plating, respectively, and thereby two categories of Co-Ni-P coatings with different Co/Ni atomic ratio were obtained. Both of them presented compact morphologies and preferential (1 1 1) crystal orientation, which were validated by FE-SEM and XRD measurements. Owing to the lower square resistance and higher magnetic properties, the Co-Ni-P coated fabric activated by Co0 activator showed a higher EMI SE (18.2-40.1 dB) at frequency of 30-1000 MHz. APTMS thin coatings were then assembled on the top of alloy coated fabrics to act as anti-corrosion barriers. Electrochemical polarization measurement in 3.5 wt.% NaCl solution showed that top-APTMS coated conductive fabric exhibited a higher corrosion resistance than the one in absence of APTMS assembly. Overall, the whole process of fabrication could be performed in several hours (or less) without any specialized equipment, which shows a great potential as EMI shielding fabrics in mass-production.

On–off switch-controlled doxorubicin release from thermo- and pH-responsive coated bimagnetic nanocarriers

Energy Technology Data Exchange (ETDEWEB)

Hammad, Mohaned; Nica, Valentin; Hempelmann, Rolf, E-mail: r.hempelmann@mx.uni-saarland.de [Saarland University, Department of Physical Chemistry (Germany)

2016-08-15

A switch-controlled drug release system is designed by coating of core/shell bimagnetic nanoparticles with a pH- and thermo-responsive polymer shell, which can be used as hyperthermic agent, drug carrier, and for controlled release. Doxorubicin is loaded onto the surface of the last coating layer, and a high loading efficiency of 90.5 % is obtained. The nanocarriers are characterized by FTIR, dynamic light scattering, Zeta potential, TEM, In vitro hyperthermia, and vibrating sample magnetometry. The core/shell magnetic nanoparticles (Zn{sub 0.4}Co{sub 0.6}Fe{sub 2}O{sub 4}@Zn{sub 0.4}Mn{sub 0.6}Fe{sub 2}O{sub 4}) exhibit a superparamagnetic behavior with a saturation magnetization around 45.6 emu/g and a high specific absorption rate of up to 360 W/g. The in vitro drug release experiments confirm that only a small amount of doxorubicin is released at body temperature and physiological pH, whereas a high drug release is obtained at acidic tumor pH under hyperthermia conditions (43 °C). The functionalized core/shell bimagnetic nanocarriers facilitate controllable release of doxorubicin as an effect of induced thermo- and pH-responsiveness of the polymer when are subjected to a high-frequency alternating magnetic field at acidic pH; thereby the drug release rate is controlled using on–off cycles of the applied field.Graphical Abstract.

Microstructure and wear resistance of laser cladded Ni-Cr-Co-Ti-V high-entropy alloy coating after laser remelting processing

Science.gov (United States)

Cai, Zhaobing; Cui, Xiufang; Liu, Zhe; Li, Yang; Dong, Meiling; Jin, Guo

2018-02-01

An attempt, combined with the technologies of laser cladding and laser remelting, has been made to develop a Ni-Cr-Co-Ti-V high entropy alloy coating. The phase composition, microstructure, micro-hardness and wear resistance (rolling friction) were studied in detail. The results show that after laser remelting, the phase composition remains unchanged, that is, as-cladded coating and as-remelted coatings are all composed of (Ni, Co)Ti2 intermetallic compound, Ti-rich phase and BCC solid solution phase. However, after laser remelting, the volume fraction of Ti-rich phase increases significantly. Moreover, the micro-hardness is increased, up to ∼900 HV at the laser remelting parameters: laser power of 1 kW, laser spot diameter of 3 mm, and laser speed of 10 mm/s. Compared to the as-cladded high-entropy alloy coating, the as-remelted high-entropy alloy coatings have high friction coefficient and low wear mass loss, indicating that the wear resistance of as-remelted coatings is improved and suggesting practical applications, like coatings on brake pads for wear protection. The worn surface morphologies show that the worn mechanism of as-cladded and as-remelted high-entropy alloy coatings are adhesive wear.

Effects of amorphous silica coating on cerium oxide nanoparticles induced pulmonary responses

Energy Technology Data Exchange (ETDEWEB)

Ma, Jane, E-mail: jym1@cdc.gov [Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV (United States); Mercer, Robert R.; Barger, Mark; Schwegler-Berry, Diane [Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV (United States); Cohen, Joel M.; Demokritou, Philip [Harvard TH Chan School of Public Health, Harvard University, Boston, MA (United States); Castranova, Vincent [School of Pharmacy, West Virginia University, Morgantown, WV (United States)

2015-10-01

Recently cerium compounds have been used in a variety of consumer products, including diesel fuel additives, to increase fuel combustion efficiency and decrease diesel soot emissions. However, cerium oxide (CeO{sub 2}) nanoparticles have been detected in the exhaust, which raises a health concern. Previous studies have shown that exposure of rats to nanoscale CeO{sub 2} by intratracheal instillation (IT) induces sustained pulmonary inflammation and fibrosis. In the present study, male Sprague–Dawley rats were exposed to CeO{sub 2} or CeO{sub 2} coated with a nano layer of amorphous SiO{sub 2} (aSiO{sub 2}/CeO{sub 2}) by a single IT and sacrificed at various times post-exposure to assess potential protective effects of the aSiO{sub 2} coating. The first acellular bronchoalveolar lavage (BAL) fluid and BAL cells were collected and analyzed from all exposed animals. At the low dose (0.15 mg/kg), CeO{sub 2} but not aSiO{sub 2}/CeO{sub 2} exposure induced inflammation. However, at the higher doses, both particles induced a dose-related inflammation, cytotoxicity, inflammatory cytokines, matrix metalloproteinase (MMP)-9, and tissue inhibitor of MMP at 1 day post-exposure. Morphological analysis of lung showed an increased inflammation, surfactant and collagen fibers after CeO{sub 2} (high dose at 3.5 mg/kg) treatment at 28 days post-exposure. aSiO{sub 2} coating significantly reduced CeO{sub 2}-induced inflammatory responses in the airspace and appeared to attenuate phospholipidosis and fibrosis. Energy dispersive X-ray spectroscopy analysis showed Ce and phosphorous (P) in all particle-exposed lungs, whereas Si was only detected in aSiO{sub 2}/CeO{sub 2}-exposed lungs up to 3 days after exposure, suggesting that aSiO{sub 2} dissolved off the CeO{sub 2} core, and some of the CeO{sub 2} was transformed to CePO{sub 4} with time. These results demonstrate that aSiO{sub 2} coating reduce CeO{sub 2}-induced inflammation, phospholipidosis and fibrosis. - Highlights: • Both

Magnetic properties of sandwiches based on Nd-Co and Y-Co amorphous alloys

International Nuclear Information System (INIS)

Ndjaka, J.M.B.; Givord, D.

1996-01-01

Y-Co/Nd-Co/Y-Co and Nd-Co/Y-Co/Nd-Co amorphous sandwiches have been prepared by d.c. triode sputtering. The chemical composition of the constituent layers is R 0.33 Co 0.67 (R=Y, Nd). In such systems, the Co moments are coupled parallel through the whole sandwich thickness by strong positive 3d-3d exchange interactions. But, the coercive fields of the constituent layers taken separately differ. In the sandwiches as well, the reversal of magnetization in the different layers occurs at different values of the applied magnetic field. This phenomenon has been analysed qualitatively in terms of creation and annihilation of walls at the interfaces between layers for sandwiches where the thicknesses of the constituent layers are about 1000 A. In sandwiches where the thickness of the constituent layers is 100 A, the wall width available is very weak and the value of the applied magnetic field necessary for the creation of such a wall is higher than the coercive field of the entire sandwich system. As a result, the magnetization of the sandwich system reverses as a whole like in homogeneous systems. (orig.)

Structural models for amorphous transition metal binary alloys

International Nuclear Information System (INIS)

Ching, W.Y.; Lin, C.C.

1976-01-01

A dense random packing of 445 hard spheres with two different diameters in a concentration ratio of 3 : 1 was hand-built to simulate the structure of amorphous transition metal-metalloid alloys. By introducing appropriate pair potentials of the Lennard-Jones type, the structure is dynamically relaxed by minimizing the total energy. The radial distribution functions (RDF) for amorphous Fe 0 . 75 P 0 . 25 , Ni 0 . 75 P 0 . 25 , Co 0 . 75 P 0 . 25 are obtained and compared with the experimental data. The calculated RDF's are resolved into their partial components. The results indicate that such dynamically constructed models are capable of accounting for some subtle features in the RDF of amorphous transition metal-metalloid alloys

Annealing Effects on the Magnetization of Co-Ni-B Amorphous Nanoparticles

International Nuclear Information System (INIS)

Vargas, J.M.

2001-01-01

Chemically prepared (Co x Ni 1-x ) 1 00 -y B y (x=0.5, 0.75, 1; y∼30) amorphous fine particles were characterized by x-ray diffraction, DTA and TGA, and in-situ magnetic measurement as a function of annealing temperature in an inert atmosphere.Magnetic measurement performed in as prepared and ∼150C degree annealed samples show an increase of the saturation magnetization and magnetic moment after thermal tretment.Room temperature magnetization increases by factors of ∼3 in average.These measurements may indicate a local re-ordering of the amorphous phase at temperatures much lower than the full crystallization temperature

Crystallization study of amorphous system Fe[sub 84-x]W[sub x]B[sub 16] (x = 3; 5)

Energy Technology Data Exchange (ETDEWEB)

Novakova, A.A.; Sidorova, G.V.; Kiseleva, T.Yu.; Szasz, A. (Dept. of Physics, State Univ., Moscow (Russia) Inst. of Metallurgy, Academy of Science, Moscow (Russia) Eoetvoes Univ., Budapest (Hungary))

1992-10-01

A complex study of the crystallization process of the amorphous system was carried out by Moessbauer spectroscopy, X-ray diffraction and DTA. Alloy samples crystallized at 600deg C contain the following phases: [alpha]-Fe, Fe[sub 3]B and solid solution (Fe, W)[sub 3]B. (orig.).

Glass solution formation in water - In situ amorphization of naproxen and ibuprofen with Eudragit® E PO

DEFF Research Database (Denmark)

Doreth, Maria; Löbmann, Korbinian; Grohganz, Holger

2016-01-01

is applicable to other drugs. Compacts of drug and Eudragit® E were compressed at a 2:1, 1:1 and 1:2 drug-to-polymer ratio (w/w) and immersed in water for 1 h. Physicochemical characteristics, potential interactions and dissolution behavior were analyzed and compared to non-immersed compacts. Both drugs formed...... a glass solution with Eudragit® E when immersed into water. In XRPD, reflections of the respective drugs decreased or disappeared completely. All samples showed a single glass transition temperature in the DSC, suggesting the formation of single phase amorphous systems. Ionic interactions between drug...... and polymer were identified by infrared spectroscopy. In the dissolution study (pH 4.1), especially the 1:1 (w/w) in situ amorphized samples showed an improved dissolution behavior compared to their non-immersed counterparts. It can be concluded that in situ amorphization is a promising method to amorphize...

Experimental investigation of phase equilibria in the Co-W-V ternary system

International Nuclear Information System (INIS)

Liu Xingjun; Zhu Yihong; Yu Yan; Wang Cuiping

2011-01-01

Highlights: → Three isothermal sections of the Co-W-V ternary system at 1100 deg. C, 1200 deg. C and 1300 deg. C were determined. → No ternary compound was found in the Co-W-V ternary system. → A stable liquid miscibility gap is newly discovered in the Co-W-V ternary system. → This work is of great essence to establish the thermodynamic database for the Co-based alloys. - Abstract: The phase equilibria in the Co-W-V ternary system were experimentally investigated by optical microscopy (OM), electron probe microanalysis (EPMA) and X-ray diffraction (XRD) on the equilibrated alloys. Three isothermal sections of the Co-W-V ternary system at 1100 deg. C, 1200 deg. C and 1300 deg. C were determined, and no ternary compound was found in this system. In addition, a novel phenomena induced by the liquid phase separation in the Co-W-V alloys was firstly discovered, suggesting that a stable liquid miscibility gap exists in the Co-W-V ternary system. The newly determined phase equilibria and firstly discovered phase separation phenomena in the Co-W-V system will provide important information for the development of Co-W based alloys.

Biomimetic calcium phosphate coating of additively manufactured porous CoCr implants

Energy Technology Data Exchange (ETDEWEB)

Lindahl, Carl [BIOMATCELL Vinn Excellence Center of Biomaterials and Cell Therapy, Gothenburg (Sweden); Department of Engineering Sciences, Ångstrom Laboratory, Uppsala University, Uppsala (Sweden); Xia, Wei, E-mail: wei.xia@angstrom.uu.se [BIOMATCELL Vinn Excellence Center of Biomaterials and Cell Therapy, Gothenburg (Sweden); Department of Engineering Sciences, Ångstrom Laboratory, Uppsala University, Uppsala (Sweden); Engqvist, Håkan [BIOMATCELL Vinn Excellence Center of Biomaterials and Cell Therapy, Gothenburg (Sweden); Department of Engineering Sciences, Ångstrom Laboratory, Uppsala University, Uppsala (Sweden); Snis, Anders [BIOMATCELL Vinn Excellence Center of Biomaterials and Cell Therapy, Gothenburg (Sweden); Arcam AB, Krokslätts Fabriker 27 A, SE-431 37 Mölndal (Sweden); Lausmaa, Jukka [BIOMATCELL Vinn Excellence Center of Biomaterials and Cell Therapy, Gothenburg (Sweden); Department of Chemistry, Materials and Surfaces, SP Technical Research Institute of Sweden, Borås (Sweden); Palmquist, Anders [BIOMATCELL Vinn Excellence Center of Biomaterials and Cell Therapy, Gothenburg (Sweden); Department of Biomaterials, Sahlgrenska Academy at the University of Gothenburg, Gothenburg (Sweden)

2015-10-30

Highlights: • A route for coating complex shaped electron beam melted implants is presented. • Biomimetic HA coatings were deposited on CoCr alloys using a solution method. • Deposited biomimetic coating was partially crystalline, slightly calcium deficient. • Coating morphology was plate-like with crystallites forming roundish flowers. • Present coating procedure could be useful for porous implants made by EBM. - Abstract: The aim of this work was to study the feasibility to use a biomimetic method to prepare biomimetic hydroxyapatite (HA) coatings on CoCr substrates with short soaking times and to characterize the properties of such coatings. A second objective was to investigate if the coatings could be applied to porous CoCr implants manufactured by electron beam melting (EBM). The coating was prepared by immersing the pretreated CoCr substrates and EBM implants into the phosphate-buffered solution with Ca{sup 2+} in sealed plastic bottles, kept at 60 °C for 3 days. The formed coating was partially crystalline, slightly calcium deficient and composed of plate-like crystallites forming roundish flowers in the size range of 300–500 nm. Cross-section imaging showed a thickness of 300–500 nm. In addition, dissolution tests in Tris–HCl up to 28 days showed that a substantial amount of the coating had dissolved, however, undergoing only minor morphological changes. A uniform coating was formed within the porous network of the additive manufactured implants having similar thickness and morphology as for the flat samples. In conclusion, the present coating procedure allows coatings to be formed on CoCr and could be used for complex shaped, porous implants made by additive manufacturing.

Biomimetic calcium phosphate coating of additively manufactured porous CoCr implants

International Nuclear Information System (INIS)

Lindahl, Carl; Xia, Wei; Engqvist, Håkan; Snis, Anders; Lausmaa, Jukka; Palmquist, Anders

2015-01-01

Highlights: • A route for coating complex shaped electron beam melted implants is presented. • Biomimetic HA coatings were deposited on CoCr alloys using a solution method. • Deposited biomimetic coating was partially crystalline, slightly calcium deficient. • Coating morphology was plate-like with crystallites forming roundish flowers. • Present coating procedure could be useful for porous implants made by EBM. - Abstract: The aim of this work was to study the feasibility to use a biomimetic method to prepare biomimetic hydroxyapatite (HA) coatings on CoCr substrates with short soaking times and to characterize the properties of such coatings. A second objective was to investigate if the coatings could be applied to porous CoCr implants manufactured by electron beam melting (EBM). The coating was prepared by immersing the pretreated CoCr substrates and EBM implants into the phosphate-buffered solution with Ca"2"+ in sealed plastic bottles, kept at 60 °C for 3 days. The formed coating was partially crystalline, slightly calcium deficient and composed of plate-like crystallites forming roundish flowers in the size range of 300–500 nm. Cross-section imaging showed a thickness of 300–500 nm. In addition, dissolution tests in Tris–HCl up to 28 days showed that a substantial amount of the coating had dissolved, however, undergoing only minor morphological changes. A uniform coating was formed within the porous network of the additive manufactured implants having similar thickness and morphology as for the flat samples. In conclusion, the present coating procedure allows coatings to be formed on CoCr and could be used for complex shaped, porous implants made by additive manufacturing.

W-containing oxide layers obtained on aluminum and titanium by PEO as catalysts in thiophene oxidation

Science.gov (United States)

Rudnev, V. S.; Lukiyanchuk, I. V.; Vasilyeva, M. S.; Morozova, V. P.; Zelikman, V. M.; Tarkhanova, I. G.

2017-11-01

W-containing oxide layers fabricated on titanium and aluminum alloys by Plasma electrolytic oxidation (PEO) have been tested in the reaction of the peroxide oxidation of thiophene. Samples with two types of coatings have been investigated. Coatings I contained tungsten oxide in the matrix and on the surface of amorphous silica-titania or silica-alumina layers, while coatings II comprised crystalline WO3 and/or Al2(WO4)3. Aluminum-supported catalyst containing a smallest amount of transition metals in the form of tungsten oxides and manganese oxides in low oxidation levels showed high activity and stability.

Performance characterization of metallic substrates coated by HVOF WC–Co

International Nuclear Information System (INIS)

Venter, Andrew M.; Oladijo, O. Philip; Luzin, Vladimir; Cornish, Lesley A.; Sacks, Natasha

2013-01-01

Integral to the performance of high-velocity oxygen-fuel (HVOF) coatings is the thermo-mechanical interaction associated with the thermal misfit, or differences in thermal expansion coefficients (CTEs), between coating and substrate. This investigation reports results on the microstructures, chemical phase content, coating–substrate misfit residual stress, and wear resistance. For this purpose a systematic characterization of WC–Co sprayed coatings on a number of substrates covering a range of CTE values were pursued for both the as-coated and heat-treated conditions. The neutron diffraction technique in conjunction with sub-millimeter sized gauge volumes enabled depth-resolved studies of the stress in the coatings and substrates by paying special attention to the determination of the stress contribution attributed by the final spray process. In the as-coated condition the stress values in the coatings were compressive for CTEs larger than that of WC–Co and tensile for CTE lower than WC–Co. Wear resistance increased for increased compressive stress and macrohardness. In the heat-treated condition, this trend became enhanced due to increased compressive stress in the coatings. - Highlights: • Four different substrate systems coated with HVOF WC-Co has been investigated. • Each substrate set encompassed the grit-blast surface and as-coated conditions, as well as their heat-treated counterparts. • Microstructural, macrohardness, wear performance and depth-resolved residual stress characterised. • Successful application of neutron strain scanning to investigating the combined systems, coatings and substrates. • Link observed between macrohardness, residual stress and wear performance

Coercivity and induced magnetic anisotropy by stress and/or field annealing in Fe- and Co- based (Finemet-type) amorphous alloys

International Nuclear Information System (INIS)

Miguel, C.; Zhukov, A.; Val, J.J. del; Gonzalez, J.

2005-01-01

Uniaxial magnetic anisotropy has been induced in amorphous Fe 73.5 Cu 1 Nb 3 Si 15.5 B 7 (Fe-rich) and (Co 77 Si 13.5 B 9.5 ) 90 Fe 7 Nb 3 (Co-rich) ferromagnetic alloys by annealing under stress and/or magnetic field. Such anisotropy plays a crucial role on the magnetization process and, consequently, determine the future applications of these materials. The mechanisms involved on the origin of such induced magnetic anisotropy showed significant differences between Fe-rich and Co-rich amorphous alloys. This work provides a comparative study of the coercive field and induced magnetic anisotropy in Fe-rich and Co-rich (Finemet) amorphous alloys treated by stress and/or field

Magnetron co-sputtering system for coating ICF targets

International Nuclear Information System (INIS)

Hsieh, E.J.; Meyer, S.F.; Halsey, W.G.; Jameson, G.T.; Wittmayer, F.J.

1981-01-01

Fabrication of Inertial Confinement Fusion (ICF) targets requires deposition of various types of coatings on microspheres. The mechanical strength, and surface finish of the coatings are of concern in ICF experiments. The tensile strength of coatings can be controlled through grain refinement, selective doping and alloy formation. We have constructed a magnetron co-sputtering system to produce variable density profile coatings with high tensile strength on microspheres

Effect of heat treatment duration on tribological behavior of electroless Ni-(high)P coatings

Science.gov (United States)

Biswas, A.; Das, S. K.; Sahoo, P.

2016-09-01

Electroless nickel coating occurs through an autocatalytic chemical reaction and without the aid of electricity. From tribological perspective, it is recommended due to its high hardness, wear resistance, lubricity and corrosion resistance properties. In this paper electroless Ni-P coatings with high phosphorous weight percentages are developed on mild steel (AISI 1040) substrates. The coatings are subjected to heat treatment at 300°C and 500°C for time durations up to 4 hours. The effect of heat treatment duration on the hardness as well as tribological properties is discussed in detail. Hardness is measured in a micro hardness tester while the tribological tests are carried out on a pin-on-disc tribotester. Wear is reported in the form of wear rates of the sample subjected to the test. As expected, heat treatment of electroless Ni-P coating results in enhancement in its hardness which in turn increases its wear resistance. The present study also finds that duration of heat treatment has quite an effect on the properties of the coating. Increase in heat treatment time in general results in increase in the hardness of the coating. Coefficient of friction is also found to be lesser for the samples heat treated for longer durations (4 hour). However, in case of wear, similar trend is not observed. Instead samples heat treated for 2 to 3 hour display better wear resistance compared to the same heat treated for 4 hour duration. The microstructure of the coating is also carried out to ensure about its proper development. From scanning electron microscopy (SEM), the coating is found to possess the conventional nodular structure while energy dispersive X-ray analysis (EDX) shows that the phosphorous content in the coating to be greater than 9%. This means that the current coating belongs to the high phosphorous category. From X-ray diffraction analysis (XRD), it is found that coating is amorphous in as-deposited condition but transforms into a crystalline structure with

Transmission electron microscopy of coatings formed by plasma electrolytic oxidation of titanium.

Science.gov (United States)

Matykina, E; Arrabal, R; Skeldon, P; Thompson, G E

2009-05-01

Transmission electron microscopy and supporting film analyses are used to investigate the changes in composition, morphology and structure of coatings formed on titanium during DC plasma electrolytic oxidation in a calcium- and phosphorus-containing electrolyte. The coatings are of potential interest as bioactive surfaces. The initial barrier film, of mixed amorphous and nanocrystalline structure, formed below the sparking voltage of 180 V, incorporates small amounts of phosphorus and calcium species, with phosphorus confined to the outer approximately 63% of the coating thickness. On commencement of sparking, calcium- and phosphorus-rich amorphous material forms at the coating surface, with local heating promoting crystallization in underlying and adjacent anodic titania. The amorphous material thickens with increased treatment time, comprising almost the whole of the approximately 5.7-microm-thick coating formed at 340 V. At this stage, the coating is approximately 4.4 times thicker than the oxidized titanium, with a near-surface composition of about 12 at.% Ti, 58 at.% O, 19 at.% P and 11 at.% Ca. Further, the amount of titanium consumed in forming the coating is similar to that calculated from the anodizing charge, although there may be non-Faradaic contributions to the coating growth.

Preparation, mechanical strengths, and thermal stability of Ni-Si-B and Ni-P-B amorphous wires

International Nuclear Information System (INIS)

Inoue, A.; Furukawa, S.; Hagiwara, M.; Masumoto, T.

1987-01-01

Ni-based amorphous wires with good bending ductility have been prepared for Ni/sub 75/Si/sub 8/B/sub 17/ and Ni/sub 78/P/sub 12/B/sub 10/ alloys containing 1 to 2 at. pct Al or Zr by melt spinning in rotating water. The enhancement of the wire-formation tendency by the addition of Al has been clarified to be due to the increase in the stability of the melt jet through the formation of a thin Al/sub 2/O/sub 3/ film on the outer surface. The maximum wire diameter is about 190 to 200 μm for the Ni-Si (or P)-B-Al alloys and increases to about 250 μm for the Ni-Si-B-Al-Cr alloys containing 4 to 6 at. pct Cr. The tensile fracture strength and fracture elongation are 2730 MPa and 2.9 pct for (N/sub 0.75/Si/sub 0.08/B/sub 0.17/)/sub 99/Al/sub 1/ wire and 2170 MPa and 2.4 pct for (Ni/sub 0.78/P/sub 0.12/B/sub 0.1/)/sub 99/Al/sub 1/ wire. These wires exhibit a fatigue limit under dynamic bending strain in air with a relative humidity of 65 pct; this limit is 0.50 pct for a NiSi-B-Al wire, which is higher by 0.15 pct than that of a Fe/sub 75/Si/sub 10/B/sub 15/ amorphous wire. Furthermore, the Ni-base wires do not fracture during a 180-deg bending even for a sample annealed at temperatures just below the crystallization temperature, in sharp contrast to high embrittlement tendency for Fe-base amorphous alloys. Thus, the Ni-based amorphous wires have been shown to be an attractive material similar to Fe- and Co-based amorphous wires because of its high static and dynamic strength, high ductility, high stability to thermal embrittlement, and good corrosion resistance

Influence of Co addition on the magnetocaloric effect of FeCoSiAlGaPCB amorphous alloys

OpenAIRE

Franco García, Victorino; Borrego Moro, Josefa María; Conde Amiano, Alejandro

2006-01-01

The FeCoSiAlGaPCB alloys can be prepared as bulk amorphous materials, with outstanding mechanical properties and increased electrical resistivity. These features can be beneficial for their application as a magnetic refrigerant. The influence of Co addition on the magnetic entropy change of the alloy has been studied. This compositional modification displaces the temperature of the peak entropy change closer to room temperature, but reduces the refrigerant capacity of the material...

Corrosion behaviour of Ni–Co alloy coatings at Kish Island

Indian Academy of Sciences (India)

In this study, the corrosion behaviour of Ni-Co alloys with low Co content, electroplated on steel substrate in sulphate bath, was investigated. The morphology of coatings was studied by optical and SEM microscopy. The corrosion products were analyzed using EDX. The results showed that Ni–1% Co coatings had a better ...

A novel Mo-W interlayer approach for CVD diamond deposition on steel

Science.gov (United States)

Kundrát, Vojtěch; Zhang, Xiaoling; Cooke, Kevin; Sun, Hailin; Sullivan, John; Ye, Haitao

2015-04-01

Steel is the most widely used material in engineering for its cost/performance ratio and coatings are routinely applied on its surface to further improve its properties. Diamond coated steel parts are an option for many demanding industrial applications through prolonging the lifetime of steel parts, enhancement of tool performance as well as the reduction of wear rates. Direct deposition of diamond on steel using conventional chemical vapour deposition (CVD) processes is known to give poor results due to the preferential formation of amorphous carbon on iron, nickel and other elements as well as stresses induced from the significant difference in the thermal expansion coefficients of those materials. This article reports a novel approach of deposition of nanocrystalline diamond coatings on high-speed steel (M42) substrates using a multi-structured molybdenum (Mo) - tungsten (W) interlayer to form steel/Mo/Mo-W/W/diamond sandwich structures which overcome the adhesion problem related to direct magnetron sputtering deposition of pure tungsten. Surface, interface and tribology properties were evaluated to understand the role of such an interlayer structure. The multi-structured Mo-W interlayer has been proven to improve the adhesion between diamond films and steel substrates by acting as an effective diffusion barrier during the CVD diamond deposition.

A novel Mo-W interlayer approach for CVD diamond deposition on steel

Energy Technology Data Exchange (ETDEWEB)

Kundrát, Vojtěch; Sullivan, John; Ye, Haitao, E-mail: h.ye@aston.ac.uk [School of Engineering and Applied Science, Aston University, Birmingham, B4 7ET (United Kingdom); Zhang, Xiaoling; Cooke, Kevin; Sun, Hailin [Miba Coating Group: Teer Coatings Ltd, West-Stone-House, West-Stone, Berry-Hill-Industrial-Estate, WR9 9AS, Droitwich (United Kingdom)

2015-04-15

Steel is the most widely used material in engineering for its cost/performance ratio and coatings are routinely applied on its surface to further improve its properties. Diamond coated steel parts are an option for many demanding industrial applications through prolonging the lifetime of steel parts, enhancement of tool performance as well as the reduction of wear rates. Direct deposition of diamond on steel using conventional chemical vapour deposition (CVD) processes is known to give poor results due to the preferential formation of amorphous carbon on iron, nickel and other elements as well as stresses induced from the significant difference in the thermal expansion coefficients of those materials. This article reports a novel approach of deposition of nanocrystalline diamond coatings on high-speed steel (M42) substrates using a multi-structured molybdenum (Mo) – tungsten (W) interlayer to form steel/Mo/Mo-W/W/diamond sandwich structures which overcome the adhesion problem related to direct magnetron sputtering deposition of pure tungsten. Surface, interface and tribology properties were evaluated to understand the role of such an interlayer structure. The multi-structured Mo-W interlayer has been proven to improve the adhesion between diamond films and steel substrates by acting as an effective diffusion barrier during the CVD diamond deposition.

A novel Mo-W interlayer approach for CVD diamond deposition on steel

Directory of Open Access Journals (Sweden)

Vojtěch Kundrát

2015-04-01

Full Text Available Steel is the most widely used material in engineering for its cost/performance ratio and coatings are routinely applied on its surface to further improve its properties. Diamond coated steel parts are an option for many demanding industrial applications through prolonging the lifetime of steel parts, enhancement of tool performance as well as the reduction of wear rates. Direct deposition of diamond on steel using conventional chemical vapour deposition (CVD processes is known to give poor results due to the preferential formation of amorphous carbon on iron, nickel and other elements as well as stresses induced from the significant difference in the thermal expansion coefficients of those materials. This article reports a novel approach of deposition of nanocrystalline diamond coatings on high-speed steel (M42 substrates using a multi-structured molybdenum (Mo – tungsten (W interlayer to form steel/Mo/Mo-W/W/diamond sandwich structures which overcome the adhesion problem related to direct magnetron sputtering deposition of pure tungsten. Surface, interface and tribology properties were evaluated to understand the role of such an interlayer structure. The multi-structured Mo-W interlayer has been proven to improve the adhesion between diamond films and steel substrates by acting as an effective diffusion barrier during the CVD diamond deposition.

The Effect of Substitution of Fe By Co on Rapidly Quenched (FeCoMoCuB Amorphous Alloys

Directory of Open Access Journals (Sweden)

Marek Paluga

2005-01-01

Full Text Available (Fe1-xCox79Mo8Cu1B15 amorphous alloys ware prepared in the form of ribbons by rapid quenching for x=0. 0.25 and 0.5. The effect of variation of Co/Fe ratio is analyzed with respect to the formation of amorphous state and to transformation of the structure into nancrystalline phases formed after subsequent thermal treatment. Selected properties and atomic structure in as-quenched state are studied by TEM, AFM, XRD any by measurement of magnetoresistance characteristics. The influence of heat treatment on transport and magnetic properties is shown on temperature dependencies of electrical resistivity and magnetization. It was founf that while the increase of Co content leads to the increase of Curie temperature of as-quenched structure, transition to nanocrystalline state is not affected in a significant manner. The as-quenched state for alloy without Co was found to contain thin crystal-containing layer which, however, was observed, contary to general behavior, at the side of the ribbon exposed to higher quenching rates.

9 July 2008 - Microsoft Co-Founder P. Allen visiting ATLAS control room and underground experimental area with Adviser J. Ellis and IT Department Head W. von Rüden.

CERN Multimedia

Maximilien Brice

2008-01-01

9 July 2008 - Microsoft Co-Founder P. Allen visiting ATLAS control room and underground experimental area with Adviser J. Ellis and IT Department Head W. von Rüden and guided by ATLAS Collaboration Users S. Goldfarb, P. Nevski and L. Price.

Effect of hydridation on structure of amorphous and amorphous-crystalline Fe40Ni40B20 and Co70Fe5Si15B10 bands

International Nuclear Information System (INIS)

Il'inskij, A.G.; Brovko, A.P.; Zelinskaya, G.M.; Kosenko, N.S.; Khristenko, T.M.; Kobzenko, G.F.; Shkola, A.A.

1988-01-01

The structure of amorphous and amorphous-crystaliline Fe 40 Ni 40 B 20 and Co 70 Fe 5 Si-1 5 B 10 alloys, exposed to hydridation at different temperatures, is studied by X-ray diffraction technique. The presence of crystalline constituent in amorphous bands was determined on DRON-3 device and by method of small-angle scattering. The experimental data obtained verify, that hydridation does not only prevent the formation of crystalline phases at annealing, but leads, as well, to disappearance of band crystalline constituent in case of its presence

Isochronal and isothermal crystallization kinetics of amorphous Fe-based alloys

International Nuclear Information System (INIS)

Zhang, J.T.; Wang, W.M.; Ma, H.J.; Li, G.H.; Li, R.; Zhang, Z.H.

2010-01-01

Using the differential scanning calorimetry (DSC), the isochronal and isothermal crystallization kinetics of amorphous Fe 61 Co 9-x Zr 8 Mo 5 W x B 17 (x = 0 and 2) ribbons was investigated by the Kissinger equation and by the Kolmogorov-Johnson-Mehl-Avrami and Ranganathan-Heimendahl equations, respectively. The results show that tungsten can improve the activation energy E 1 K for the first crystallization in the isochronal annealing process and activation energy E n for the nucleation in the isothermal annealing process, which can be ascribed to the dissolution of tungsten in the amorphous phase. Meanwhile, tungsten can decrease the activation energy E 2 K for the second crystallization in the isochronal annealing process and growth activation energy E g in the isothermal annealing process, which is possibly associated with the formation of W-rich compound after the early nucleation process.

Comparative study of NiW, NiMo and MoW prepared by mechanical alloying

International Nuclear Information System (INIS)

Gonzalez, G.; Sagarzazu, A.; Villalba, R.; Ochoa, J.

2007-01-01

The present work concern the amorphisation process induced by mechanical alloying in the NiW, NiMo and MoW systems. The alloys chosen combine a group of transition elements varying from very similar atomic radius and electronic valences (MoW) to different ones (NiW and NiMo). The three systems achieved an amorphous state after 50 h of milling. The mechanism of amorphisation proposed for NiW and NiMo was the combined effect of an excess concentration of the solute atoms entering into the structure of one of the elements and a critical concentration of defects. Continuous formation of an amorphous phase at the interface of the crystalline phase was observed during the process. MoW seems to amorphize by continuous reduction of grain size down to a critical value where the amorphisation takes place

Extrinsic- and intrinsic-defect creation in amorphous SiO2

International Nuclear Information System (INIS)

Devine, R.A.B.; Francou, J.

1990-01-01

We have studied the creation efficiency of various intrinsic and extrinsic defects in high-[OH] amorphous silica subjected to the ultraviolet emission from an O 2 plasma or 60 Co γ-ray radiation. Both oxygen-vacancy- and nitrogen-related defects are observed following γ-ray irradiation or ultraviolet exposure. The wavelength range responsible for defect creation is estimated to be 200 approx-lt λ approx-lt 300 nm (4 approx-lt E photon approx-lt 5.9 eV). The ultraviolet power output of the plasma estimated by comparing defect yields with those from a Hg lamp (λ=185 and 254 nm) suggests 200 approx-lt P approx-lt 900 mW cm -2 for a plasma power density ∼300 mW cm -3 . Nonbridging oxygen-hole centers and hydrogen-related defect centers as well as methyl radical (CH 3 . ) defects are observed after γ-ray irradiation but not after ultraviolet exposure. The efficiency of creation of the various defects is material dependent

Thermal Spray Coatings for High-Temperature Corrosion Protection in Biomass Co-Fired Boilers

Science.gov (United States)

Oksa, M.; Metsäjoki, J.; Kärki, J.

2015-01-01

There are over 1000 biomass boilers and about 500 plants using waste as fuel in Europe, and the numbers are increasing. Many of them encounter serious problems with high-temperature corrosion due to detrimental elements such as chlorides, alkali metals, and heavy metals. By HVOF spraying, it is possible to produce very dense and well-adhered coatings, which can be applied for corrosion protection of heat exchanger surfaces in biomass and waste-to-energy power plant boilers. Four HVOF coatings and one arc sprayed coating were exposed to actual biomass co-fired boiler conditions in superheater area with a probe measurement installation for 5900 h at 550 and 750 °C. The coating materials were Ni-Cr, IN625, Fe-Cr-W-Nb-Mo, and Ni-Cr-Ti. CJS and DJ Hybrid spray guns were used for HVOF spraying to compare the corrosion resistance of Ni-Cr coating structures. Reference materials were ferritic steel T92 and nickel super alloy A263. The circulating fluidized bed boiler burnt a mixture of wood, peat and coal. The coatings showed excellent corrosion resistance at 550 °C compared to the ferritic steel. At higher temperature, NiCr sprayed with CJS had the best corrosion resistance. IN625 was consumed almost completely during the exposure at 750 °C.

A Magnetic Sensor with Amorphous Wire

Directory of Open Access Journals (Sweden)

Dongfeng He

2014-06-01

Full Text Available Using a FeCoSiB amorphous wire and a coil wrapped around it, we have developed a sensitive magnetic sensor. When a 5 mm long amorphous wire with the diameter of 0.1 mm was used, the magnetic field noise spectrum of the sensor was about 30 pT/ÖHz above 30 Hz. To show the sensitivity and the spatial resolution, the magnetic field of a thousand Japanese yen was scanned with the magnetic sensor.

Amorphous drugs and dosage forms

DEFF Research Database (Denmark)

Grohganz, Holger; Löbmann, K.; Priemel, P.

2013-01-01

The transformation to an amorphous form is one of the most promising approaches to address the low solubility of drug compounds, the latter being an increasing challenge in the development of new drug candidates. However, amorphous forms are high energy solids and tend to recry stallize. New...... formulation principles are needed to ensure the stability of amorphous drug forms. The formation of solid dispersions is still the most investigated approach, but additional approaches are desirable to overcome the shortcomings of solid dispersions. Spatial separation by either coating or the use of micro-containers...... before single molecules are available for the formation of crystal nuclei, thus stabilizing the amorphous form....

Vacuum Plasma Spraying W-coated Reduced Activation Structural Steels for Fusion Plasma Facing Components

Energy Technology Data Exchange (ETDEWEB)

Noh, Sanghoon; Kim, Tae Kyu [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2014-05-15

Tungsten (W) and its alloys are considered as candidate materials for plasma facing materials of the first wall and diverter components in fusion reactor systems because of high sputtering resistance and low tritium retention in a fusion environment. Therefore, it is considered that the joining between W and reduced activation structural steels, and its evaluation, are critical issues for the development of fusion reactors. However, the joining between these materials is a very challenging process because of significant differences in their physical properties, particularly the mismatch of coefficients of thermal expansion (CTE). For instance, the CTE of pure W is known to be about 4.3Χ10{sup -6}K{sup -1}; however, that of martensitic steels reaches over three times, about 12-14Χ10{sup -6}K{sup -1} at room temperature even up to 373K. Nevertheless, several joining techniques have been developed for joining between W and structural steels, such as a vapor deposition method, brazing and diffusion bonding. Meanwhile, vacuum plasma spraying (VPS) is supposed to be one of the prospective methods to fabricate a sufficient W layer on the steel substrates because of the coating of a large area with a relatively high fabricating rate. In this study, the VPS method of W powders on reduced activation steels was employed, and its microstructure and hardness distribution were investigated. ODS ferritic steels and F82H steel were coated by VPS-W, and the microstructure and hardness distribution were investigated. A microstructure analysis revealed that pure W was successfully coated on steel substrates by the VPS process without an intermediate layer, in spite of a mismatch of the CTE between dissimilar materials. After neutron irradiation, irradiation hardening significantly occurred in the VPSW. However, the hardening of VPS-W was lesser than that of bulk W irradiated HFIR at 773K. Substrate materials, ODS ferritic steels, and F82H steel, did not show irradiation hardening

Evaluation of a Prototype pCO2 Optical Sensor

Science.gov (United States)

Sanborn-Marsh, C.; Sutton, A.; Sabine, C. L.; Lawrence-Salvas, N.; Dietrich, C.

2016-12-01

Anthropogenic greenhouse gas emissions continue to rise, driving climate change and altering the ocean carbonate systems. Carbonate chemistry can be characterized by any two of the four parameters: pH, total alkalinity, dissolved inorganic carbon, and partial pressure of dissolved carbon dioxide gas (pCO2). To fully monitor these dynamic systems, researchers must deploy a more temporally and spatially comprehensive sensor network. Logistical challenges, such as the energy consumption, size, lifetime, depth range, and cost of pCO2 sensors have limited the network's reach so far. NOAA's Pacific Marine Environmental Laboratory has conducted assessment tests of a pCO2 optical sensor (optode), recently developed by Atamanchuk et al (2014). We hope to deploy this optode in the summer of 2017 on high-resolution moored profiler, along with temperature, salinity, and oxygen sensors. While most pCO2 optodes have energy consumptions of 3-10 W, this 36mm-diameter by 86mm-long instrument consumes a mere 7-80 mW. Initial testing showed that its accuracy varied within an absolute range of 2-75 μatm, depending on environmental conditions, including temperature, salinity, response time, and initial calibration. Further research independently examining the effects of each variable on the accuracy of the data will also be presented.

Electrochemically assisted co-deposition of calcium phosphate/collagen coatings on carbon/carbon composites

Energy Technology Data Exchange (ETDEWEB)

Zhao Xueni [C/C Composites Technology Research Center, State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi' an, Shaanxi 710072 (China); Hu Tao [C/C Composites Technology Research Center, State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi' an, Shaanxi 710072 (China); Department of Cardiology, Xijing Hospital, Fourth Military Medical University, Xi' an, Shaanxi 710032 (China); Li Hejun, E-mail: lihejun@nwpu.edu.cn [C/C Composites Technology Research Center, State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi' an, Shaanxi 710072 (China); Chen Mengdi; Cao Sheng; Zhang Leilei [C/C Composites Technology Research Center, State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi' an, Shaanxi 710072 (China); Hou Xianghui [Department of Mechanical, Materials and Manufacturing Engineering, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom)

2011-02-01

Calcium phosphate (CaP)/collagen coatings were prepared on the surface of carbon/carbon (C/C) composites by electrochemically assisted co-deposition technique. The effects of collagen concentration in the electrolyte on morphology, structure and composition of the coatings were systematically investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transformed infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The adhesive strength of the coatings was also evaluated by scratch tests and tensile bond tests. It was demonstrated that the coatings of three-dimensional collagen network structure was formed on the C/C composites from the electrolyte containing collagen. The surface of the collagen network was covered by uniform CaP aggregates. The coatings were actually composites of CaP and collagen. Hydroxyapatite (HA) was a favorable composition in the coatings with the increase of the collagen concentration in the electrolyte. The formed collagen network increased the cohesive and adhesive strength of the coatings. The adhesive strength between the coatings and substrates increased as the collagen concentration in the electrolyte increased. The coatings prepared at the collagen concentration of 500 mg/L in the electrolyte were not scraped off until the applied load reached 32.0 {+-} 2.2 N and the average tensile adhesive strength of the coatings was 4.83 {+-} 0.71 MPa. After C/C coated with composite coatings (500 mg/L) being immersed in a 10{sup -3} M Ca (OH){sub 2} solution at 30-33 deg. C for 96 h, nano-structured HA/collagen coatings similar to the natural human bone were obtained on the C/C.

Thermal oxidation of reactively sputtered amorphous W80N20 films

International Nuclear Information System (INIS)

Vu, Q.T.; Pokela, P.J.; Garden, C.L.; Kolawa, E.; Raud, S.; Nicolet, M.

1990-01-01

The oxidation behavior of reactively sputtered amorphous tungsten nitride of composition W 80 N 20 was investigated in dry and wet oxidizing ambient in the temperature range of 450 degree C--575 degree C. A single WO 3 oxide phase is observed. The growth of the oxide follows a parabolic time dependence which is attributed to a process controlled by the diffusivity of the oxidant in the oxide. The oxidation process is thermally activated with an activation energy of 2.5±0.05 eV for dry ambient and 2.35±0.05 eV for wet ambient. The pre-exponential factor of the reaction constant for dry ambient is 1.1x10 21 A 2 /min; that for wet ambient is only about 10 times less and is equal to 1.3x10 20 A 2 /min

Canted spin structure and the first order magnetic transition in CoFe{sub 2}O{sub 4} nanoparticles coated by amorphous silica

Energy Technology Data Exchange (ETDEWEB)

Lyubutin, I.S. [Shubnikov Institute of Crystallography, Russian Academy of Sciences, Moscow 119333 (Russian Federation); Starchikov, S.S., E-mail: sergey.s.starchikov@gmail.com [Shubnikov Institute of Crystallography, Russian Academy of Sciences, Moscow 119333 (Russian Federation); Gervits, N.E.; Korotkov, N.Yu.; Dmitrieva, T.V. [Shubnikov Institute of Crystallography, Russian Academy of Sciences, Moscow 119333 (Russian Federation); Lin, Chun-Rong, E-mail: crlinspin@gmail.com [Department of Applied Physics, National Pingtung University, Pingtung County 90003, Taiwan (China); Tseng, Yaw-Teng [Department of Applied Physics, National Pingtung University, Pingtung County 90003, Taiwan (China); Shih, Kun-Yauh [Department of Applied Chemistry, National Pingtung University, Pingtung County 90003, Taiwan (China); Lee, Jiann-Shing [Department of Applied Physics, National Pingtung University, Pingtung County 90003, Taiwan (China); Wang, Cheng-Chien [Department of Chemical and Materials Engineering, Southern Taiwan University of Science and Technology, Tainan 710, Taiwan (China)

2016-10-01

The functional polymer (PMA-co-MAA) latex microspheres were used as a core template to prepare magnetic hollow spheres consisting of CoFe{sub 2}O{sub 4}/SiO{sub 2} composites. The spinel type crystal structure of CoFe{sub 2}O{sub 4} ferrite is formed under annealing, whereas the polymer cores are completely removed after annealing at 450 °C. Magnetic and Mössbauer spectroscopy measurements reveal very interesting magnetic properties of the CoFe{sub 2}O{sub 4}/SiO{sub 2} hollow spheres strongly dependent on the particle size which can be tuned by the annealing temperature. In the ground state of low temperatures, the CoFe{sub 2}O{sub 4} nanoparticles are in antiferromagnetic state due to the canted magnetic structure. Under heating in the applied field, the magnetic structure gradually transforms from canted to collinear, which increases the magnetization. The Mössbauer data revealed that the small size CoFe{sub 2}O{sub 4}/SiO{sub 2} particles (2.2–4.3 nm) do not show superparamagnetic behavior but transit from the magnetic to the paramagnetic state by a jump-like magnetic transition of the first order This effect is a specific property of the magnetic nanoparticles isolated by inert material, and can be initiated by internal pressure creating at the particle surface. The suggested method of synthesis can be modified with various bio-ligands on the silane surface, and such materials can find many applications in diagnostics and bio-separation. - Highlights: • CoFe{sub 2}O{sub 4}/SiO{sub 2} nanocomposites in shell of hollow microcapsules designed for biomedical applications • The CoFe{sub 2}O{sub 4} particle size and magnetic properties can be tuned by thermal treatment • Canted spin structure in the CoFe{sub 2}O{sub 4} nanoparticles coated by SiO{sub 2} • The first order magnetic transition in the CoFe{sub 2}O{sub 4} nanoparticles coated by silica.

Deconvolution of ferromagnetic resonance in devitrification process of Co-based amorphous alloys

International Nuclear Information System (INIS)

Montiel, H.; Alvarez, G.; Betancourt, I.; Zamorano, R.; Valenzuela, R.

2006-01-01

Ferromagnetic resonance (FMR) measurements were carried out on soft magnetic amorphous ribbons of composition Co 66 Fe 4 B 12 Si 13 Nb 4 Cu prepared by melt spinning. In the as-cast sample, a simple FMR spectrum was apparent. For treatment times of 5-20 min a complex resonant absorption at lower fields was detected; deconvolution calculations were carried out on the FMR spectra and it was possible to separate two contributions. These results can be interpreted as the combination of two different magnetic phases, corresponding to the amorphous matrix and nanocrystallites. The parameters of resonant absorptions can be associated with the evolution of nanocrystallization during the annealing

Electrophoretically applied dielectrics for amorphous metal foils used in pulsed power saturable reactors

International Nuclear Information System (INIS)

Sharp, D.J.; Harjes, H.C.; Mann, G.A.

1989-01-01

Amorphous metal foil-wound inductors have been tested as ferromagnetic saturable inductive elements for pulsed-power (multi-terawatt) switching modules in the inertial confinement fusion program at Sandia National Laboratories. In simulated capacitor testing premature dielectric breakdown of thin polyethylene terephthalate film insulation in the inductor windings occurs at considerably below 2500 V. This appears to be due to inadvertant dielectric damage from micro-spikes on the amorphous foil surface. Electron micrographs and dielectric breakdown data illustrate that electrophoretically-applied dielectric coatings, deposited from organic aqueous colloid dispersions, can be used to provide insulating coatings on the foil which provide a 240% improvement (6000 V) in the breakdown strength of wound amorphous foil inductors. The theory and operation of a dedicated electrophoretic continuous coating system is described. The machine was constructed and successfully applied for dielectric coating of amorphous metal foil. Additional possible applications exist for practical dielectric coating of metallic films or foils used in various commercial wound-type capacitor structures. 7 refs., 9 figs

Induced anisotropy in amorphous Sm-Co sputtered films

International Nuclear Information System (INIS)

Chen, K.; Hegde, H.; Cadieu, F.J.

1992-01-01

The variation of the in-the-film-plane anisotropy constant, K u , with composition and the magnitude of the field, H s , applied in plane during the sputter deposition of amorphous Sm x Co 1-x , 0.08≤x≤0.40, thin films has been studied. We demonstrate here that with a large H s , 5.0 kOe, a well defined and large in-the-film-plane anisotropy can be obtained. An exceptionally high value of K u =3.3x10 6 erg/cm 3 has been obtained. For the loop measured along the in-plane hard direction, the opening of the loop was undetectable, and the loop along the easy axis was a perfect rectangle. For certain conditions, the anisotropy field measured perpendicular to the film plane when corrected for demagnetization (N d =4π) was the same as that for the in-plane measurements. It is concluded that surface induced short range ordering was the origin of the anisotropy observed in amorphous films deposited in a magnetic field. The formation mechanism is different from that of the short range ordering induced by field annealing

The effect of Co-Co3O4 coating on the electrochemical properties of Si as an anode material for Li ion battery

International Nuclear Information System (INIS)

Kang, Yong-Mook; Lee, Sang-Min; Sung, Min-Seok; Jeong, Goo-Jin; Kim, Joon-Sup; Kim, Sung-Soo

2006-01-01

In order to improve the electrochemical performance of Si as an anode material for Li ion secondary batteries, a biphasic layer composed of Co and Co 3 O 4 was coated on Si particles by sol-gel method. Compared to Si, Co-Co 3 O 4 coated Si showed the drastic improvement in several electrochemical properties, such as initial coulombic efficiency (55% → 88%), cyclic efficiency and cycle life. The comparison between Co-Co 3 O 4 coated Si and heat-treated Si without the coating let us know that the improvement of electrochemical properties only results from Co-Co 3 O 4 coating layer. Little changed cyclic properties (cyclic efficiency and cycle life) of Co-Co 3 O 4 coated Si even at a higher charge-discharge rate insinuated that Co-Co 3 O 4 coating layer plays a crucial role in maintaining the electronic contacts between particles and conducting parts. When trying to measure a thickness variation of the electrodes each containing Si and Co-Co 3 O 4 coated Si as active materials, it was notified that Co-Co 3 O 4 coating layer can accommodate the volume expansion of Si during Li + insertion, which has its original thickness almost recovered after Li + extraction

Experimental study on friction and wear behaviour of amorphous carbon coatings for mechanical seals in cryogenic environment

Science.gov (United States)

Wang, Jianlei; Jia, Qian; Yuan, Xiaoyang; Wang, Shaopeng

2012-10-01

The service life and the reliability of contact mechanical seal are directly affected by the wear of seal pairs (rotor vs. stator), especially under the cryogenic environment in liquid rocket engine turbopumps. Because of the lower friction and wear rate, amorphous carbon (a-C) coatings are the promising protective coatings of the seal pairs for contact mechanical seal. In this paper, a-C coatings were deposited on 9Cr18 by pulsed DC magnetron sputtering. The tribological performances of the specimen were tested under three sealed fluid conditions (air, water and liquid nitrogen). The results show that the coatings could endure the cryogenic temperature while the friction coefficients decrease with the increased contact load. Under the same contact condition, the friction coefficient of the a-C coatings in liquid nitrogen is higher than that in water and that they are in air. The friction coefficients of the a-C coatings in liquid nitrogen range from 0.10 to 0.15. In the cryogenic environment, the coatings remain their low specific wear rates (0.9 × 10-6 to 1.8 × 10-6 mm3 N-1 m-1). The results provide an important reference for designing a water lubricated bearing or a contact mechanical seal under the cryogenic environment that is both reliable and has longevity.

The study of Zn–Co alloy coatings electrochemically deposited by pulse current

Directory of Open Access Journals (Sweden)

Tomić Milorad V.

2012-01-01

Full Text Available The electrochemical deposition by pulse current of Zn-Co alloy coatings on steel was examined, with the aim to find out whether pulse plating could produce alloys that could offer a better corrosion protection. The influence of on-time and the average current density on the cathodic current efficiency, coating morphology, surface roughness and corrosion stability in 3% NaCl was examined. At the same Ton/Toff ratio the current efficiency was insignificantly smaller for deposition at higher average current density. It was shown that, depending on the on-time, pulse plating could produce more homogenous alloy coatings with finer morphology, as compared to deposits obtained by direct current. The surface roughness was the greatest for Zn-Co alloy coatings deposited with direct current, as compared with alloy coatings deposited with pulse current, for both examined average current densities. It was also shown that Zn-Co alloy coatings deposited by pulse current could increase the corrosion stability of Zn-Co alloy coatings on steel. Namely, alloy coatings deposited with pulse current showed higher corrosion stability, as compared with alloy coatings deposited with direct current, for almost all examined cathodic times, Ton. Alloy coatings deposited at higher average current density showed greater corrosion stability as compared with coatings deposited by pulse current at smaller average current density. It was shown that deposits obtained with pulse current and cathodic time of 10 ms had the poorest corrosion stability, for both investigated average deposition current density. Among all investigated alloy coatings the highest corrosion stability was obtained for Zn-Co alloy coatings deposited with pulsed current at higher average current density (jav = 4 A dm-2.

Effect Of Low-Temperature Annealing On The Properties Of Ni-P Amorphous Alloys Deposited Via Electroless Plating

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Zhao Guanlin

2015-06-01

Full Text Available Amorphous Ni-P alloys were prepared via electroless plating and annealing at 200°C at different times to obtain different microstructures. The effects of low-temperature annealing on the properties of amorphous Ni-P alloys were studied. The local atomic structure of the annealed amorphous Ni-P alloys was analyzed by calculating the atomic pair distribution function from their X-ray diffraction patterns. The results indicate that the properties of the annealed amorphous Ni-P alloys are closely related to the order atomic cluster size. However, these annealed Ni-P alloys maintained their amorphous structure at different annealing times. The variation in microhardness is in agreement with the change in cluster size. By contrast, the corrosion resistance of the annealed alloys in 3.5 wt% NaCl solution increases with the decrease in order cluster size.

Development of Protective Coatings for Co-Sequestration Processes and Pipelines

Energy Technology Data Exchange (ETDEWEB)

Bierwagen, Gordon; Huang, Yaping

2011-11-30

The program, entitled Development of Protective Coatings for Co-Sequestration Processes and Pipelines, examined the sensitivity of existing coating systems to supercritical carbon dioxide (SCCO2) exposure and developed new coating system to protect pipelines from their corrosion under SCCO2 exposure. A literature review was also conducted regarding pipeline corrosion sensors to monitor pipes used in handling co-sequestration fluids. Research was to ensure safety and reliability for a pipeline involving transport of SCCO2 from the power plant to the sequestration site to mitigate the greenhouse gas effect. Results showed that one commercial coating and one designed formulation can both be supplied as potential candidates for internal pipeline coating to transport SCCO2.

Optical properties of amorphous SiO2-TiO2 multi-nanolayered coatings for 1064-nm mirror technology

Science.gov (United States)

Magnozzi, M.; Terreni, S.; Anghinolfi, L.; Uttiya, S.; Carnasciali, M. M.; Gemme, G.; Neri, M.; Principe, M.; Pinto, I.; Kuo, L.-C.; Chao, S.; Canepa, M.

2018-01-01

The use of amorphous, SiO2-TiO2 nanolayered coatings has been proposed recently for the mirrors of 3rd-generation interferometric detectors of gravitational waves, to be operated at low temperature. Coatings with a high number of low-high index sub-units pairs with nanoscale thickness were found to preserve the amorphous structure for high annealing temperatures, a key factor to improve the mechanical quality of the mirrors. The optimization of mirror designs based on such coatings requires a detailed knowledge of the optical properties of sub-units at the nm-thick scale. To this aim we have performed a Spectroscopic Ellipsometry (SE) study of amorphous SiO2-TiO2 nanolayered films deposited on Si wafers by Ion Beam Sputtering (IBS). We have analyzed films that are composed of 5 and 19 nanolayers (NL5 and NL19 samples) and have total optical thickness nominally equivalent to a quarter of wavelength at 1064 nm. A set of reference optical properties for the constituent materials was obtained by the analysis of thicker SiO2 and TiO2 homogeneous films (∼ 120 nm) deposited by the same IBS facility. By flanking SE with ancillary techniques, such as TEM and AFM, we built optical models that allowed us to retrieve the broad-band (250-1700 nm) optical properties of the nanolayers in the NL5 and NL19 composite films. In the models which provided the best agreement between simulation and data, the thickness of each sub-unit was fitted within rather narrow bounds determined by the analysis of TEM measurements on witness samples. Regarding the NL5 sample, with thickness of 19.9 nm and 27.1 nm for SiO2 and TiO2 sub-units, respectively, the optical properties presented limited variations with respect to the thin film counterparts. For the NL19 sample, which is composed of ultrathin sub-units (4.4 nm and 8.4 nm for SiO2 and TiO2, respectively) we observed a significant decrease of the IR refraction index for both types of sub-units; this points to a lesser mass density with

Isochronal and isothermal crystallization kinetics of amorphous Fe-based alloys

Energy Technology Data Exchange (ETDEWEB)

Zhang, J.T. [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Jinan 250061 (China); Wang, W.M., E-mail: weiminw@sdu.edu.cn [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Jinan 250061 (China); Key Lab of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Ma, H.J.; Li, G.H.; Li, R.; Zhang, Z.H. [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Jinan 250061 (China)

2010-06-10

Using the differential scanning calorimetry (DSC), the isochronal and isothermal crystallization kinetics of amorphous Fe{sub 61}Co{sub 9-x}Zr{sub 8}Mo{sub 5}W{sub x}B{sub 17} (x = 0 and 2) ribbons was investigated by the Kissinger equation and by the Kolmogorov-Johnson-Mehl-Avrami and Ranganathan-Heimendahl equations, respectively. The results show that tungsten can improve the activation energy E{sub 1}{sup K} for the first crystallization in the isochronal annealing process and activation energy E{sub n} for the nucleation in the isothermal annealing process, which can be ascribed to the dissolution of tungsten in the amorphous phase. Meanwhile, tungsten can decrease the activation energy E{sub 2}{sup K} for the second crystallization in the isochronal annealing process and growth activation energy E{sub g} in the isothermal annealing process, which is possibly associated with the formation of W-rich compound after the early nucleation process.

High-field magnetization behavior in random anisotropy amorphous Co-Er alloys

Science.gov (United States)

Lassri, H.; Driouch, L.; Krishnan, R.

1994-05-01

Amorphous Co1-xErx ribbons with x=55 and 65 were prepared by the melt-spinning technique. Magnetization measurements were carried out in the temperature range 4-100 K under high magnetic fields up to 20 T. Even at 20 T the saturation is not fully attained. Assuming that Co has no moment in the alloy with x=65 the Er moment is found to be 7.0μB which indicates a speromagnetic spin structure. The Co moment in the alloy with x=55 is then found to be 0.1μB, which is negligibly small. By analyzing the approach to saturation using Chudnovsky's theory we have extracted some fundamental parameters.

Evaluation of electrodeposited Mn-Co protective coatings on Crofer 22 APU steel

DEFF Research Database (Denmark)

Molin, Sebastian

2018-01-01

Interconnects used in Solid Oxide Cells stacks require protective coatings to lower their parabolic rate constant and block chromium evaporation (on the air side). In this work four different protective coatings on steel are evaluated for their high temperature corrosion resistance and electrical...... conductivity. A commercial electroplating process was used for the preparation of coatings with different Mn/Co ratios on Crofer 22 APU steel. Oxidation of samples was performed in air at 800°C for 1000 hours. Postmortem analysis of the coated samples was performed by scanning electron microscopy and x......-ray diffractomettry. Based on the results, influence of the Co/Mn ratio on the resulting corrosion properties are discussed. Parabolic rate constant of the coated samples is the lowest for the MnCo sample, whereas electrical resistance is the lowest for the Co sample, which has a corrosion rate similar to the not-coated...

Amino acids as co-amorphous stabilizers for poorly water-soluble drugs - Part 2

DEFF Research Database (Denmark)

Löbmann, K.; Laitinen, R.; Strachan, C.

2013-01-01

spectroscopy. Molecular interactions of the drugs carbamazepine and indomethacin with the amino acids arginine, phenylalanine, and tryptophan were investigated. The amino acids were chosen from the biological target site of both drugs and prepared as co-amorphous formulations together with the drugs...

P(o-chlorophenol–co-o-hydroxyphenol: kinetic formation studies and pH-sensor application

Directory of Open Access Journals (Sweden)

Said M. Sayyah

2017-03-01

Full Text Available Electrochemical copolymerization of o-chlorophenol (o-ClPh with o-hydroxyphenol (o-HOPh was conducted in aqueous H2SO4 using cyclic voltammetry technique at the Pt electrode. The reaction rate was found to be of the second order in the monomer concentration and first order in the acid concentration. The activation energy, enthalpy, and entropy for the copolymerization were found to be 20.20 kJ mol-1, 19.24 kJ mol-1 and -281.47 J K-1 mol-1, respectively. The obtained copolymer films show smooth feature with amorphous nature. Copolymer films adhere Pt electrode very well and show less reactivity in the H2SO4 medium. The pH sensitivity of the poly(oClPh-co-HOPh-modified electrode has been investigated potentiometrically using different polymer thicknesses. The potentiometric responses to pH change of the poly(oClPh-co-HOPh-modified electrode appeared reversible and linear in the range from pH 2-11 with a maximum sub-Nernstian potentiometric response slope of 40.7 mV/pH (30 °C. The slope became close to 56.2 mV/pH in the range from pH 4 to 9 at (30 °C. The poly(oClPh-co-HOPh-modified electrode readily responded to pH change but was not stable with time.

Coating of graphite flakes with MgO/carbon nanocomposite via gas state reaction

International Nuclear Information System (INIS)

Sharif, M.; Faghihi-Sani, M.A.; Golestani-Fard, F.; Saberi, A.; Soltani, Ali Khalife

2010-01-01

Coating of graphite flakes with MgO/carbon nanocomposite was carried out via gaseous state reaction between mixture of Mg metal, CO gas and graphite flakes at 1000 o C. XRD and FE-SEM analysis of coating showed that the coating was comprised of MgO nano particles and amorphous carbon distributed smoothly and covered the graphite surface evenly. Thermodynamic calculations were employed to predict the reaction sequences as well as phase stability. The effect of coating on water wettability and oxidation resistance of graphite was studied using contact angle measurement and TG analysis, respectively. It was demonstrated that the reaction between Mg and CO could result in MgO/C nanocomposite deposition. The coating improved water wettability of graphite and also enhanced the oxidation resistance of graphite flakes significantly. Also the graphite coating showed significant phenolic resin-wettabilty owing to high surface area of such hydrophilic nano composite coating. The importance of graphite coating is explained with emphasis on its potential application in graphite containing refractories.

FY05 HPCRM Annual Report: High-Performance Corrosion-Resistant Iron-Based Amorphous Metal Coatings Evaluation of Corrosion Resistance FY05 HPCRM Annual Report No. Rev. 1DOE-DARPA Co-Sponsored Advanced Materials Program

International Nuclear Information System (INIS)

Farmer, J C; Haslam, J J; Day, S D

2007-01-01

New corrosion-resistant, iron-based amorphous metals have been identified from published data or developed through combinatorial synthesis, and tested to determine their relative corrosion resistance. Many of these materials can be applied as coatings with advanced thermal spray technology. Two compositions have corrosion resistance superior to wrought nickel-based Alloy C-22 (UNS No. N06022) in some very aggressive environments, including concentrated calcium-chloride brines at elevated temperature. Two Fe-based amorphous metal formulations have been found that appear to have corrosion resistance comparable to, or better than that of Ni-based Alloy C-22, based on breakdown potential and corrosion rate. Both Cr and Mo provide corrosion resistance, B enables glass formation, and Y lowers critical cooling rate (CCR). SAM1651 has yttrium added, and has a nominal critical cooling rate of only 80 Kelvin per second, while SAM2X7 (similar to SAM2X5) has no yttrium, and a relatively high critical cooling rate of 610 Kelvin per second. Both amorphous metal formulations have strengths and weaknesses. SAM1651 (yttrium added) has a low critical cooling rate (CCR), which enables it to be rendered as a completely amorphous thermal spray coating. Unfortunately, it is relatively difficult to atomize, with powders being irregular in shape. This causes the powder to be difficult to pneumatically convey during thermal spray deposition. Gas atomized SAM1651 powder has required cryogenic milling to eliminate irregularities that make flow difficult. SAM2X5 (no yttrium) has a high critical cooling rate, which has caused problems associated with devitrification. SAM2X5 can be gas atomized to produce spherical powders of SAM2X5, which enable more facile thermal spray deposition. The reference material, nickel-based Alloy C-22, is an outstanding corrosion-resistant engineering material. Even so, crevice corrosion has been observed with C-22 in hot sodium chloride environments without buffer

Magnetization processes in amorphous R-Co/R'-Co/R-Co sandwiches (R, R'=Y, Nd, Gd, Er)

International Nuclear Information System (INIS)

Dieny, B.; Givord, D.; Ndjaka, J.M.B.; Alameda, J.M.

1990-01-01

Sandwiches consisting of three amorphous layers (R 0.33 ,Co 0.67 )( 1000 A / R ' 0.33 ,Co 0.67 ) 1000 A / (R 0.33 Co 0.67 ) 1000 A , have been prepared by dc triode sputtering (R, R' are rare-earth elements). The systems chosen are such that the bulk magnetization alternates from one layer to the next or the coercivity of each layer is significantly different. Magnetic transitions are observed under field. They have been quantitatively analyzed in terms of successive reversals of magnetization in the different layers. The creation or annihilation of planar Bloch walls parallel to the surface are associated with the magnetic transitions. The wall energy and wall width depend essentially on the competition between exchange energy and Zeeman energy. It is suggested that the existence of such Bloch walls may favor magnetization reversal in thin films by coherent processes

Effect of H2O and Y(O on Oxidation Behavior of NiCoCrAl Coating Within Thermal Barrier Coating

Directory of Open Access Journals (Sweden)

WANG Yi-qun

2017-04-01

Full Text Available NiCoCrAl coatings containing Y and Y oxide were made using vacuum plasma deposition and high-velocity oxygen fuel respectively, high temperature oxidation dynamics and cross-section microstructures of NiCoCrAl+Y and NiCoCrAl+Y(O coatings in Ar-16.7%O2, Ar-3.3%H2O and Ar-0.2%H2-0.9%H2O at 1100℃ were investigated by differential thermal analysis (DTA and optical and electron microscope. The influencing mechanism of Y oxide on the oxidation of coatings at different atmosphere was compared by computation using First-Principles. The results show that Al2O3 layer on NiCoCrAl+Y coatings has more holes for internal oxidation on account of the element Y diffusion and enrichment on the interface. In addition, steam can promote the internal oxidation. While a thinner and uniform alumina form on NiCoCrAl+Y(O coatings because element Y is pinned by oxygen atoms during the preparation of coatings. Water vapor has less influence on protective alumina formation on the NiCoCrAl+Y(O coating. Therefore, oxidation behavior of NiCoCrAl coatings vary in composition and structure in different oxidizing atmosphere. Besides, Y and Y-enrichment oxides have key influences on the microstructure and the growth rate.

Soft magnetic properties of bulk amorphous Co-based samples

International Nuclear Information System (INIS)

Fuezer, J.; Bednarcik, J.; Kollar, P.

2006-01-01

Ball milling of melt-spun ribbons and subsequent compaction of the resulting powders in the supercooled liquid region were used to prepare disc shaped bulk amorphous Co-based samples. The several bulk samples have been prepared by hot compaction with subsequent heat treatment (500 deg C - 575 deg C). The influence of the consolidation temperature and follow-up heat treatment on the magnetic properties of bulk samples was investigated. The final heat treatment leads to decrease of the coercivity to the value between the 7.5 to 9 A/m (Authors)

Dual pO2/pCO2 fibre optic sensing film.

Science.gov (United States)

Davenport, John J; Hickey, Michelle; Phillips, Justin P; Kyriacou, Panayiotis A

2017-05-15

A fibre optic multi-sensor has been developed for biomedical sensing applications using a tip coating solution sensitive to both oxygen and carbon dioxide. An oxygen sensitive phosphorescence quenching complex based on platinum octaethylporphyrin (PtOEP) was combined with a carbon dioxide sensitive phosphorescence compound based on 8-hydroxypyrene-1,3,6-trisulfonic acid trisodium salt (HPTS). When excited by blue light (470 nm), the resultant coating had two fluorescent peaks at 515 nm (green) and 645 nm (red) which responded to partial pressure of CO 2 and O 2 respectively. The sensor was tested in vitro and shown to be able to measure CO 2 and O 2 simultaneously and in real time, with calibration constants of 0.0384 kPa -1 and 0.309 kPa -1 respectively. The O 2 sensitive peak received some overlap from the 515 nm peak (0.38% of peak intensity) as well as some cross-sensitivity (maximum, 5.1 kPa pCO 2 gave a measurement equivalent to 0.43 kPa of O 2 , a ratio of 0.08 : 1). However, these effects can be subtracted from measurements and no significant cross-sensitivity or overlap was seen in CO 2 measurements from O 2 . This novel compound presents great potential for use in medical sensors and we expect it to be important to a wide range of future applications.

Amino acids as co-amorphous stabilizers for poorly water soluble drugs--Part 1

DEFF Research Database (Denmark)

Löbmann, Korbinian; Grohganz, Holger; Laitinen, Riikka

2013-01-01

molecular weight excipients that form specific molecular interactions with the drug resulting in co-amorphous forms. The two poorly water soluble drugs carbamazepine and indomethacin were combined with amino acids from the binding sites of the biological receptors of these drugs. Mixtures of drug...

Engineering of giant magnetoimpedance effect of amorphous and nanocrystalline microwires

Directory of Open Access Journals (Sweden)

V. Zhukova

2016-12-01

Full Text Available We present our studies of the factors affecting soft magnetic properties and giant magnetoimpedance effect in thin amorphous and nanocrystalline microwires. We showed that the magnetoelastic anisotropy is one of the most important parameters that determine magnetic softness and GMI effect of glass-coated microwires  and annealing can be very effective for manipulation the magnetic properties of amorphous ferromagnetic glass-coated microwires. Considerable magnetic softening and increasing of the GMI effect is observed in Fe-rich nanocrystalline FINEMET-type glass-coated microwires after the nanocrystallization.

Effect of Co crystallinity on Co/CNT catalytic activity in CO/CO{sub 2} hydrogenation and CO disproportionation

Energy Technology Data Exchange (ETDEWEB)

Chernyak, Sergei A., E-mail: chernyak.msu@gmail.com [Lomonosov Moscow State University, Department of Chemistry, Leninskiye Gory 1-3, Moscow 119991 (Russian Federation); Kurnakov Institute of General and Inorganic Chemistry of the Russian Academy of Sciences, Department of Physical Chemistry, Leninsky Avenue 31, Moscow 119991 (Russian Federation); Suslova, Evgeniya V.; Egorov, Alexander V.; Maslakov, Konstantin I. [Lomonosov Moscow State University, Department of Chemistry, Leninskiye Gory 1-3, Moscow 119991 (Russian Federation); Savilov, Serguei V.; Lunin, Valery V. [Lomonosov Moscow State University, Department of Chemistry, Leninskiye Gory 1-3, Moscow 119991 (Russian Federation); Kurnakov Institute of General and Inorganic Chemistry of the Russian Academy of Sciences, Department of Physical Chemistry, Leninsky Avenue 31, Moscow 119991 (Russian Federation)

2016-05-30

Highlights: • Amorphous and crystalline Co supported on CNTs were obtained by tuning of CNT surface. • CO and CO{sub 2} hydrogenation does not occur on amorphous Co particles. • Thermal activation of amorphous Co led to crystallization of metal. • Amorphous Co promotes CO disproportionation. • Carbon shells around the amorphous metal particles after the CO hydrogenation. - Abstract: Carbon nanotubes (CNTs) with different degree of surface oxidation were used as supports for 5 wt.% Co catalysts. CNTs and Co/CNT catalysts were analyzed by XPS, nitrogen adsorption, TEM and electron diffraction to reveal their structure. High oxidation degree of CNT surface (8.6 at.% of O) and low Co loading led to predominantly amorphous Co species. This resulted in the absence of catalytic activity in both CO and CO{sub 2} hydrogenation in opposite to the catalyst supported on less oxidized CNTs (5.4 at.% of O) where Co species were found to be crystalline. Thermal treatment of inactive catalyst in H{sub 2} and He led to the formation of Co crystal phase which was active in catalysis. Co particle size in catalyst supported on strongly oxidized CNTs was unchanged during CO hydrogenation in opposite to Co supported on less oxidized CNTs. Carbon shell formation on the surface of amorphous Co particles during CO hydrogenation was revealed, which testified CO disproportionation. Qualitative mechanism of CO hydrogenation on small Co particles was proposed.

Microstructure and Antiwear Property of Laser Cladding Ni-Co Duplex Coating on Copper.

Science.gov (United States)

Wang, Yiyong; Liang, Zhipeng; Zhang, Junwei; Ning, Zhe; Jin, Hui

2016-07-28

Ni-Co duplex coatings were cladded onto Cu to improve the antiwear properties of Cu products. Prior to laser cladding, n-Al₂O₃/Ni layers were introduced as interlayers between laser cladding coatings and Cu substrates to improve the laser absorptivity of these substrates and ensure defect-free laser cladding coatings. The structure and morphology of the coatings were characterized by scanning electron microscopy and optical microscopy, and the phases of the coatings were analyzed by X-ray diffraction. Their hardness was measured using a microhardness tester. Experimental results showed that defect-free composite coatings were obtained and that the coatings were metallurgically bonded to the substrates. The surface of the Ni-Co duplex coatings comprised a Co-based solid solution, Cr₇C₃, (Fe,Ni) 23 C₆, and other strengthening phases. The microhardness and wear resistance of the duplex coatings were significantly improved compared with the Cu substrates. The average microhardness of the cladded coatings was 845.6 HV, which was approximately 8.2 times greater than that of the Cu substrates (102.6 HV). The volume loss of the Cu substrates was approximately 7.5 times greater than that of the Ni-Co duplex coatings after 60 min of sliding wear testing. The high hardness of and lack of defects in the Ni-Co duplex coatings reduced the plastic deformation and adhesive wear of the Cu substrates, resulting in improved wear properties.

Microstructure and Antiwear Property of Laser Cladding Ni–Co Duplex Coating on Copper