The Digital Health Scorecard: A New Health Literacy Metric for NCD Prevention and Care.

Science.gov (United States)

Ratzan, Scott C; Weinberger, Michael B; Apfel, Franklin; Kocharian, Gary

2013-06-01

According to the World Health Organization, 3 out of 5 deaths worldwide are due to common, chronic conditions, such as heart and respiratory diseases, cancer, and diabetes. These noncommunicable diseases (NCDs) are linked to multiple lifestyle risk factors, including smoking, the harmful use of alcohol, and physical inactivity. They are associated with other "intermediate" risk factors, such as elevated body mass index (BMI), hypertension, hyperlipidemia, and hyperglycemia. Taking action to reduce these 7 risk factors can help people protect themselves against leading causes of death. All of these risk factors are measurable and modifiable, but globally available, cost-effective, and easy-to-use outcome metrics that can drive action on all levels do not yet exist. The Digital Health Scorecard is being proposed as a dynamic, globally available digital tool to raise public, professional, and policy maker NCD health literacy (the motivation and ability to access, understand, communicate, and use information to improve health and reduce the incidence of NCD). Its aim is to motivate and empower individuals to make the behavioral and choice changes needed to improve their health and reduce NCD risk factors by giving unprecedented access to global data intelligence, creating awareness, making links to professional and community-based support services and policies, and providing a simple way to measure and track risk changes. Moreover, it provides health care professionals, communities, institutions, workplaces, and nations with a simple metric to monitor progress toward agreed local, national, and global NCD targets. Copyright © 2013 World Heart Federation (Geneva). Published by Elsevier B.V. All rights reserved.

Method of producing a carbon coated ceramic membrane and associated product

Science.gov (United States)

Liu, Paul K. T.; Gallaher, George R.; Wu, Jeffrey C. S.

1993-01-01

A method of producing a carbon coated ceramic membrane including passing a selected hydrocarbon vapor through a ceramic membrane and controlling ceramic membrane exposure temperature and ceramic membrane exposure time. The method produces a carbon coated ceramic membrane of reduced pore size and modified surface properties having increased chemical, thermal and hydrothermal stability over an uncoated ceramic membrane.

Performance Testing of Suspension Plasma Sprayed Thermal Barrier Coatings Produced with Varied Suspension Parameters

Directory of Open Access Journals (Sweden)

Nicholas Curry

2015-07-01

Full Text Available Suspension plasma spraying has become an emerging technology for the production of thermal barrier coatings for the gas turbine industry. Presently, though commercial systems for coating production are available, coatings remain in the development stage. Suitable suspension parameters for coating production remain an outstanding question and the influence of suspension properties on the final coatings is not well known. For this study, a number of suspensions were produced with varied solid loadings, powder size distributions and solvents. Suspensions were sprayed onto superalloy substrates coated with high velocity air fuel (HVAF -sprayed bond coats. Plasma spray parameters were selected to generate columnar structures based on previous experiments and were maintained at constant to discover the influence of the suspension behavior on coating microstructures. Testing of the produced thermal barrier coating (TBC systems has included thermal cyclic fatigue testing and thermal conductivity analysis. Pore size distribution has been characterized by mercury infiltration porosimetry. Results show a strong influence of suspension viscosity and surface tension on the microstructure of the produced coatings.

Room temperature diamond-like carbon coatings produced by low energy ion implantation

Energy Technology Data Exchange (ETDEWEB)

Markwitz, A., E-mail: a.markwitz@gns.cri.nz [Department for Ion Beam Technologies, GNS Science, 30 Gracefield Road, Lower Hutt (New Zealand); The MacDiarmid Institute for Advanced Materials and Nanotechnology (New Zealand); Mohr, B.; Leveneur, J. [Department for Ion Beam Technologies, GNS Science, 30 Gracefield Road, Lower Hutt (New Zealand)

2014-07-15

Nanometre-smooth diamond-like carbon coatings (DLC) were produced at room temperature with ion implantation using 6 kV C{sub 3}H{sub y}{sup +} ion beams. Ion beam analysis measurements showed that the coatings contain no heavy Z impurities at the level of 100 ppm, have a homogeneous stoichiometry in depth and a hydrogen concentration of typically 25 at.%. High resolution TEM analysis showed high quality and atomically flat amorphous coatings on wafer silicon. Combined TEM and RBS analysis gave a coating density of 3.25 g cm{sup −3}. Raman spectroscopy was performed to probe for sp{sup 2}/sp{sup 3} bonds in the coatings. The results indicate that low energy ion implantation with 6 kV produces hydrogenated amorphous carbon coatings with a sp{sup 3} content of about 20%. Results highlight the opportunity of developing room temperature DLC coatings with ion beam technology for industrial applications.

Optically transparent, superhydrophobic, biocompatible thin film coatings and methods for producing same

Energy Technology Data Exchange (ETDEWEB)

Armstrong, Beth L.; Aytug, Tolga; Paranthaman, Mariappan Parans; Simpson, John T.; Hillesheim, Daniel A.; Trammell, Neil E.

2017-09-05

An optically transparent, hydrophobic coating, exhibiting an average contact angle of at least 100 degrees with a drop of water. The coating can be produced using low-cost, environmentally friendly components. Methods of preparing and using the optically transparent, hydrophobic coating.

Involving private healthcare practitioners in an urban NCD sentinel surveillance system: lessons learned from Pune, India.

Science.gov (United States)

Kroll, Mareike; Phalkey, Revati; Dutta, Sayani; Shukla, Sharvari; Butsch, Carsten; Bharucha, Erach; Kraas, Frauke

2016-01-01

Despite the rising impact of non-communicable diseases (NCDs) on public health in India, lack of quality data and routine surveillance hampers the planning process for NCD prevention and control. Current surveillance programs focus largely on communicable diseases and do not adequately include the private healthcare sector as a major source of care in cities. The objective of the study was to conceptualize, implement, and evaluate a prototype for an urban NCD sentinel surveillance system among private healthcare practitioners providing primary care in Pune, India. We mapped all private healthcare providers in three selected areas of the city, conducted a knowledge, attitude, and practice survey with regard to surveillance among 258 consenting practitioners, and assessed their willingness to participate in a routine NCD surveillance system. In total, 127 practitioners agreed and were included in a 6-month surveillance study. Data on first-time diagnoses of 10 selected NCDs alongside basic demographic and socioeconomic patient information were collected onsite on a monthly basis using a paper-based register. Descriptive and regression analyses were performed. In total, 1,532 incident cases were recorded that mainly included hypertension ( n =622, 41%) and diabetes ( n =460, 30%). Dropout rate was 10% ( n =13). The monthly reporting consistency was quite constant, with the majority ( n =63, 50%) submitting 1-10 cases in 6 months. Average number of submitted cases was highest among allopathic practitioners (17.4). A majority of the participants ( n =104, 91%) agreed that the surveillance design could be scaled up to cover the entire city. The study indicates that private primary healthcare providers (allopathic and alternate medicine practitioners) play an important role in the diagnosis and treatment of NCDs and can be involved in NCD surveillance, if certain barriers are addressed. Main barriers observed were lack of regulation of the private sector, cross

Structure of Biocompatible Coatings Produced from Hydroxyapatite Nanoparticles by Detonation Spraying

OpenAIRE

Nosenko, Valentyna; Strutynska, Nataliia; Vorona, Igor; Zatovsky, Igor; Dzhagan, Volodymyr; Lemishko, Sergiy; Epple, Matthias; Prymak, Oleg; Baran, Nikolai; Ishchenko, Stanislav; Slobodyanik, Nikolai; Prylutskyy, Yuriy; Klyui, Nickolai; Temchenko, Volodymyr

2015-01-01

Detonation-produced hydroxyapatite coatings were studied by scanning electron microscopy (SEM), X-ray powder diffraction (XRD), Raman spectroscopy, and electron paramagnetic resonance (EPR) spectroscopy. The source material for detonation spraying was a B-type carbonated hydroxyapatite powder. The coatings consisted of tetracalcium phosphate and apatite. The ratio depended slightly on the degree of crystallinity of the initial powder and processing parameters of the coating preparation. The t...

Anodization process produces opaque, reflective coatings on aluminum

Science.gov (United States)

1965-01-01

Opaque, reflective coatings are produced on aluminum articles by an anodizing process wherein the anodizing bath contains an aqueous dispersion of finely divided insoluble inorganic compounds. These particles appear as uniformly distributed occlusions in the anodic deposit on the aluminum.

Mg-containing hydroxyapatite coatings produced by plasma electrolytic oxidation of titanium

Energy Technology Data Exchange (ETDEWEB)

Antonio, Cesar Augusto; Rangel, Elidiane Cipriano; Durrant, Steven Frederick; Cruz, Nilson Cristino da, E-mail: cesar.augustoa@hotmail.com [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Sorocaba, SP (Brazil). Lab. de Plasmas Tecnologicos; Delgado-Silva, Adriana de Oliveira [Universidade Federal de Sao Carlos (UFSCar), Sorocaba, SP (Brazil); Tabacniks, Manfredo H. [Universidade de Sao Paulo (USP), SP (Brazil). Instituto de Fisica

2017-07-15

Plasma Electrolytic Oxidation (PEO) is promising for the processing of biomaterials because it enables the production of surfaces with adjustable composition and structure. In this work, aimed at the improvement of the bioactivity of titanium, PEO has been used to grow calcium phosphide coatings on titanium substrates. The effects of the addition of magnesium acetate to the electrolytes on the composition of the coatings produced during 120 s on Ti disks using bipolar voltage pulses and solutions of calcium and magnesium acetates and sodium glycerophosphate as electrolytes have been studied. Scanning electron microscopy, X-ray energy dispersive spectroscopy, Rutherford backscattering spectroscopy, X-ray diffractometry with Rietveld refinement and profilometry were used to characterize the modified samples. Coatings composed of nearly 50 % of Mg-doped hydroxyapatite have been produced. In certain conditions up to 4% Mg can be incorporated into the coating without any observable significant structural modifications of the hydroxyapatite. (author)

Novel Alkyd-Type Coating Resins Produced Using Cationic Polymerization [PowerPoint

Energy Technology Data Exchange (ETDEWEB)

Chisholm, Bret; Kalita, Harjyoti; Alam, Samim; Jayasooriyamu, Anurad; Fernando, Shashi; Samanata, Satyabrata; Bahr, James; Selvakumar, Sermadurai; Sibi, Mukund; Vold, Jessica; Ulven, Chad

2014-04-07

Novel, partially bio-based poly(vinyl ether) copolymers derived from soybean oil and cyclohexyl vinyl ether (CHVE) were produced by cationic polymerization and investigated for application as alkyd-type surface coatings. Compared to conventional alkyd resins, which are produced by high temperature melt condensation polymerization, the poly(vinyl ether)s provide several advantages. These advantages include miler, more energy efficient polymer synthesis, elimination of issues associated with gelation during polymer synthesis, production of polymers with well-defined composition and relatively narrow molecular weight distribution, and elimination of film formation and physical property issues associated with entrained monomers, dimers, trimmers, etc. The results of the studied showed that the thermal, mechanical, and physical properties of the coatings produced from these novel polymers varied considerable as a function of polymer composition and cure temperature. Overall, the results suggest a good potential for these novel copolymers to be used for coatings cured by autoxidation.

Prevention and control of mental illnesses and mental health: National Action Plan for NCD Prevention, Control and Health Promotion in Pakistan.

Science.gov (United States)

Nishtar, Sania; Minhas, Fareed A; Ahmed, Ashfaq; Badar, Asma; Mohamud, Khalif Bile

2004-12-01

As part of the National Action Plan for Non-communicable Disease Prevention, Control and Health Promotion in Pakistan (NAP-NCD), mental illnesses have been grouped alongside non-communicable diseases (NCD) within a combined strategic framework in order to synchronize public health actions. The systematic approach for mental illnesses is centred on safeguarding the rights of the mentally ill, reducing stigma and discrimination, and de-institutionalisation and rehabilitation of the mentally ill in the community outlining roles of healthcare providers, the community, legislators and policy makers. The approach has implications for support functions in a number of areas including policy building, manpower and material development and research. Priority action areas for mental health as part of NAP-NCD include the integration of surveillance of mental illnesses in a comprehensive population-based NCD surveillance system; creating awareness about mental health as part of an integrated NCD behavioural change communication strategy; integration of mental health with primary healthcare; the development of sustainable public health infrastructure to support community mental health initiatives; building capacity of the health system in support of prevention and control activities; effective implementation of existing legislation and harmonizing working relationships with law enforcing agencies. NAP-NCD also stresses on the need to integrate mental health into health services as part of a sustainable and integrated medical education programme for all categories of healthcare providers and the availability of essential psychotropic drugs at all healthcare levels. It lays emphasis on protecting the interests of special groups such as prisoners, refugees and displaced persons, women, children and individuals with disabilities. Furthermore, it promotes need-based research for contemporary mental health issues.

Erosion resistance and adhesion of composite metal/ceramic coatings produced by plasma spraying

OpenAIRE

Ramm , D.; Hutchings , I.; Clyne , T.

1993-01-01

Ceramic coatings can exhibit greater erosion resistance than most metallic coatings. Such coatings are conveniently produced by thermal spraying. Unfortunately, thermally sprayed ceramic coatings often exhibit poor adhesion, partly as a consequence of the development of residual stresses during spraying and subsequent cooling. Composite coatings have been studied using aluminium/alumina deposits on steel substrates. The incorporation of ceramics within a ductile matrix has potential for sharp...

Engaging the private sector to strengthen NCD prevention and control

OpenAIRE

Allen, Luke; Bloomfield, Ashley

2016-01-01

All around the world private enterprises influence health through the sale of both harmful and health-promoting commodities, as well as lobbying and marketing activities. As globalisation further strengthens the role of the private sector as a major driver of the non-communicable disease (NCD) pandemic, engaging with the private sector to prevent and control these conditions has become increasingly important. In recognition of this fact, the 2011 UN High-Level Political Declaration on NCDs2 c...

Structure of Biocompatible Coatings Produced from Hydroxyapatite Nanoparticles by Detonation Spraying

Science.gov (United States)

Nosenko, Valentyna; Strutynska, Nataliia; Vorona, Igor; Zatovsky, Igor; Dzhagan, Volodymyr; Lemishko, Sergiy; Epple, Matthias; Prymak, Oleg; Baran, Nikolai; Ishchenko, Stanislav; Slobodyanik, Nikolai; Prylutskyy, Yuriy; Klyui, Nickolai; Temchenko, Volodymyr

2015-12-01

Detonation-produced hydroxyapatite coatings were studied by scanning electron microscopy (SEM), X-ray powder diffraction (XRD), Raman spectroscopy, and electron paramagnetic resonance (EPR) spectroscopy. The source material for detonation spraying was a B-type carbonated hydroxyapatite powder. The coatings consisted of tetracalcium phosphate and apatite. The ratio depended slightly on the degree of crystallinity of the initial powder and processing parameters of the coating preparation. The tetracalcium phosphate phase was homogeneous; the apatite phase contained defects localized on the sixfold axis and consisted of hydroxyapatite and oxyapatite. Technological factors contributing to the transformation of hydroxyapatite powder structure during coating formation by detonation spraying are discussed.

Apparatus for producing carbon-coated nanoparticles and carbon nanospheres

Energy Technology Data Exchange (ETDEWEB)

Perry, W. Lee; Weigle, John C.; Phillips, Jonathan

2015-10-20

An apparatus for producing carbon-coated nano- or micron-scale particles comprising a container for entraining particles in an aerosol gas, providing an inlet for carbon-containing gas, providing an inlet for plasma gas, a proximate torch for mixing the aerosol gas, the carbon-containing gas, and the plasma gas, bombarding the mixed gases with microwaves, and providing a collection device for gathering the resulting carbon-coated nano- or micron-scale particles. Also disclosed is a method and apparatus for making hollow carbon nano- or micro-scale spheres.

China's Efforts on Management, Surveillance, and Research of Noncommunicable Diseases: NCD Scorecard Project.

Science.gov (United States)

Zhu, Xiao-Lei; Luo, Jie-Si; Zhang, Xiao-Chang; Zhai, Yi; Wu, Jing

The incidence of noncommunicable diseases (NCDs) is rising dramatically throughout the world. Aspects of researches concerned with the improvement and development of prevention and control of NCDs have been conducted. Furthermore, the influence of most determinants of the major NCDs has showed that a broad and deep response involving stakeholders in different sectors is required in the prevention and control of NCDs. China has experienced an increase in NCDs in a short period compared with many countries. To address the burden of NCDs in China, it is important to learn about the progress that has been made in prevention and control of NCDs in China and worldwide, informed by opinions of stakeholders in different areas. In 2014, GRAND South developed the NCD Scorecard instrument to evaluate progress of NCD prevention and control in 23 countries through a 2-round Delphi process. The scorecard included 51 indicators in 4 domains: governance, surveillance and research, prevention and risk factors, and health system response. Stakeholders were then selected in the areas of government, nongovernmental organizations, private sectors, and academia to join the NCD Scorecard survey. Indicators of progress were scored by stakeholders from 0 (no activity), 1 (present but not adequate), and 2 (adequate) to 3 (highly adequate) and then the percentage of progress in each domain was calculated, representing the current situation in each country. There were 14 indicators in the domains of governance and surveillance and research. Of 429 stakeholders worldwide, 41 in China participated in the survey. China scored in the top 5 out of all participating countries in those 2 domains, scoring 67% in governance and 64% in surveillance and research. Indicators on which China scored particularly well included having a well-resourced unit or department responsible for NCDs, having a strong national system for recording the cause of all deaths, and having a system of NCD surveillance. Areas

Using Bonding Enamel-Coated Steel Fixtures to Produce More Durable Brick/Masonry Structures

Science.gov (United States)

2010-02-01

Initial tests with enameled metal straps cracked all the test cylinders and straps would not pull out BUILDING STRONG® New Strong Durable Ties...BUILDING STRONG® Using Bonding Enamel -Coated Steel Fixtures to Produce More Durable Brick/Masonry Structures Principal Investigator: Steven C...COVERED 00-00-2010 to 00-00-2010 4. TITLE AND SUBTITLE Using Bonding Enamel -Coated Steel Fixtures to Produce More Durable Brick/Masonry

Characterization of industrially produced galvannealed coating using cross-sectional specimen in TEM

International Nuclear Information System (INIS)

Chakraborty, A.; Saha, R.; Ray, R.K.

2009-01-01

Galvannealed coated sheet steels are extensively used in the automotive industry due to their inherent advantages, as compared to other zinc based coating, such as excellent spot weldability, good corrosion resistance and better paintability. Despite the above advantages, galvannealed coating suffers from poor formability due to the presence of hard and brittle Fe-Zn intermetallic phases. The formability of the coating depends on the amount and orientation of different Fe-Zn intermetallic phases. The present study deals with the characterization of an industrially produced galvannealed coating using cross-sectional specimen in a Transmission Electron Microscope. From the selected area diffraction patterns obtained in Transmission Electron Microscope, the orientations of the delta phase were calculated.

Corrosion resistance of Cu-Al coatings produced by thermal spray

Directory of Open Access Journals (Sweden)

Laura Marcela Dimaté Castellanos

2012-01-01

Full Text Available Many components in the shipbuilding industry are made of copper-based alloys. These pieces tend to break due to corrosion generated by a marine environment; such components can be salvaged through surface engineering, through deposition of suitable coatings. This paper studied the influence of three surface preparation methods involving phosphor bronze substrates concerning the corrosion resistance of commercial coatings having Al-Cu +11% Fe chemical composition. The surface was prepared using three methods: sand blasting, shot blasting and metal polishing with an abrasive disk (with and without a base layer. The deposited coatings were micro-structurally characterised by x-ray diffraction (XRD, optical microscopy and scanning electron microscopy (SEM. Corrosion resistance was evaluated by electrochemical test electrochemical impedance spectroscopy (EIS. Surfaces prepared by sandblasting showed the best resistance to corrosion, so these systems could be a viable alternative for salvaging certain parts in the marine industry. The corrosion mechanisms for the coatings produced are discussed in this research.

Amorphous boron coatings produced with vacuum arc deposition technology

CERN Document Server

Klepper, C C; Yadlowsky, E J; Carlson, E P; Keitz, M D; Williams, J M; Zuhr, R A; Poker, D B

2002-01-01

In principle, boron (B) as a material has many excellent surface properties, including corrosion resistance, very high hardness, refractory properties, and a strong tendency to bond with most substrates. The potential technological benefits of the material have not been realized, because it is difficult to deposit it as coatings. B is difficult to evaporate, does not sputter well, and cannot be thermally sprayed. In this article, first successful deposition results from a robust system, based on the vacuum (cathodic) arc technology, are reported. Adherent coatings have been produced on 1100 Al, CP-Ti, Ti-6Al-4V, 316 SS, hard chrome plate, and 52 100 steel. Composition and thickness analyses have been performed by Rutherford backscattering spectroscopy. Hardness (H) and modules (E) have been evaluated by nanoindentation. The coatings are very pure and have properties characteristic of B suboxides. A microhardness of up to 27 GPa has been measured on a 400-nm-thick film deposited on 52 100 steel, with a corresp...

Conversion Coatings Produced on AZ61 Magnesium Alloy by Low-Voltage Process

Directory of Open Access Journals (Sweden)

Nowak M.

2016-03-01

Full Text Available The resultes of anodic oxide conversion coatings on wrought AZ61 magnesium alloy production are describe. The studies were conducted in a solution containing: KOH (80 g/l and KF (300 g/l using anodic current densities of 3, 5 and 10 A/dm2 and different process durations. The obtained coatings were examined under a microscope and corrosion tests were performed by electrochemical method. Based on these results, it was found that the low-voltage process produces coatings conferring improved corrosion resistance to the tested magnesium alloy.

Erosion resistance and adhesion of composite metal/ceramic coatings produced by plasma spraying

International Nuclear Information System (INIS)

Ramm, D.A.J.; Hutchings, I.M.; Clyne, T.W.

1993-01-01

Ceramic coatings can exhibit greater erosion resistance than most metallic coatings. Such coatings are conveniently produced by thermal spraying. Unfortunately, thermally sprayed ceramic coatings often exhibit poor adhesion, partly as a consequence of the development of residual stresses during spraying and subsequent cooling. Composite coatings have been studied using aluminium/alumina deposits on steel substrates. The incorporation of ceramics within a ductile matrix has potential for sharply reducing the erosive wear at high erodent impact angles, whilst retaining the good erosion resistance of ceramics at low angles. It is shown that the proportion of metal and ceramic at the free surface can be specified so as to optimise the erosion resistance. Experiments have also been carried out on the resistance of the coatings to debonding during four-point bending of the coated substrate. Progress is being made towards the tailoring of composition profiles in graded coatings so as to optimise the combination of erosion resistance and adhesion. (orig.)

Microscopic Analysis and Electrochemical Behavior of Fe-Based Coating Produced by Laser Cladding

Directory of Open Access Journals (Sweden)

Jinlin Chen

2017-10-01

Full Text Available The effect of laser cladding on the surface microstructure and corrosion properties of coated/uncoated specimens were investigated. Fe-based alloy coating was produced on 35CrMo steel by laser cladding. The phase composition, microstructure, interface element distribution, microhardness and corrosion resistance of the cladding coating were measured. The results show that the cladding layer is mainly composed of α-Fe phases, the microstructure presents a gradient distribution, and a good metallurgical bond is formed at the boundary with the substrate. Microhardness profiles show that the average microhardness of the cladding coating is about 2.1 times higher than that of the uncoated specimen. In addition, the electrochemical results show that the coated specimen exhibits far better corrosion resistance than to the uncoated specimen.

Joint International Workshop on Professional Learning, Competence Development and Knowledge Management - LOKMOL and L3NCD

NARCIS (Netherlands)

Memmel, Martin; Ras, Eric; Weibelzahl, Stephan; Burgos, Daniel; Olmedilla, Daniel; Wolpers, Martin

2006-01-01

Memmel, M., Ras, E., Weibelzahl, S., Burgos, D., Olmedilla, D., & Wolpers, M. (2006). Joint International Workshop on Professional Learning, Competence Development and Knowledge Management - LOKMOL and L3NCD. Proceedings of ECTEL 2006. October 2nd-4th, Crete, Greece. Retrieved October 2nd, 2006,

Laminar iridium coating produced by pulse current electrodeposition from chloride molten salt

Energy Technology Data Exchange (ETDEWEB)

Zhu, Li’an, E-mail: mr_zla@163.com; Bai, Shuxin; Zhang, Hong; Ye, Yicong

2013-10-01

Due to the unique physical and chemical properties, Iridium (Ir) is one of the most promising oxidation-resistant coatings for refractory materials above 1800 °C in aerospace field. However, the Ir coatings prepared by traditional methods are composed of columnar grains throughout the coating thickness. The columnar structure of the coating is considered to do harm to its oxidation resistance. The laminar Ir coating is expected to have a better high-temperature oxidation resistance than the columnar Ir coating does. The pulse current electrodeposition, with three independent parameters: average current density (J{sub m}), duty cycle (R) and pulse frequency (f), is considered to be a promising method to fabricate layered Ir coating. In this study, laminar Ir coatings were prepared by pulse current electrodeposition in chloride molten salt. The morphology, roughness and texture of the coatings were determined by scanning electron microscope (SEM), profilometer and X-ray diffraction (XRD), respectively. The results showed that the laminar Ir coatings were composed of a nucleation layer with columnar structure and a growth layer with laminar structure. The top surfaces of the laminar Ir coatings consisted of cauliflower-like aggregates containing many fine grains, which were separated by deep grooves. The laminar Ir coating produced at the deposition condition of 20 mA/cm{sup 2} (J{sub m}), 10% (R) and 6 Hz (f) was quite smooth (R{sub a} 1.01 ± 0.09 μm) with extremely high degree of preferred orientation of 〈1 1 1〉, and its laminar structure was well developed with clear boundaries and uniform thickness of sub-layers.

Microstructural, mechanical and oxidation features of NiCoCrAlY coating produced by plasma activated EB-PVD

International Nuclear Information System (INIS)

He, Jian; Guo, Hongbo; Peng, Hui; Gong, Shengkai

2013-01-01

NiCoCrAlY coatings produced by electron beam-physical vapor deposition (EB-PVD) have been extensively used as the oxidation resistance coatings or suitable bond coats in thermal barrier coating (TBC) system. However, the inherent imperfections caused by EB-PVD process degrade the oxidation resistance of the coatings. In the present work, NiCoCrAlY coatings were creatively produced by plasma activated electron beam-physical vapor deposition (PA EB-PVD). The novel coatings showed a terraced substructure on the surface of each grain due to the increased energy of metal ions and enhanced mobility of adatoms. Also a strong (1 1 1) crystallographic texture of γ/γ′ grains was observed. The toughness of the coatings got remarkably improved compared with the coatings deposited by conventional EB-PVD and the oxidation behavior at 1373 K showed that the novel coatings had excellent oxidation resistance. The possible mechanism was finally discussed.

Relative Importance of Various Sources of Defect-Producing Hydrogen Introduced into Steel During Application of Vitreous Coatings

Science.gov (United States)

Moore, Dwight G; Mason, Mary A; Harrison, William N

1953-01-01

When porcelain enamels or vitreous-type ceramic coatings are applied to ferrous metals, there is believed to be an evolution of hydrogen gas both during and after the firing operation. At elevated temperatures rapid evolution may result in blistering while if hydrogen becomes trapped in the steel during the rapid cooling following the firing operation gas pressures may be generated at the coating-metal interface and flakes of the coating literally blown off the metal. To determine experimentally the relative importance of the principal sources of the hydrogen causing the defects, a procedure was devised in which heavy hydrogen (deuterium) was substituted in turn for regular hydrogen in each of five possible hydrogen-producing operations in the coating process. The findings of the study were as follows: (1) the principal source of the defect-producing hydrogen was the dissolved water present in the enamel frit that was incorporated into the coating. (2) the acid pickling, the milling water, the chemically combined water in the clay, and the quenching water were all minor sources of defect-producing hydrogen under the test conditions used. Confirming experiments showed that fishscaling could be eliminated by using a water-free coating.

Moisture resistant and anti-reflection optical coatings produced by plasma polymerization of organic compounds

Science.gov (United States)

Hollahan, J. R.; Wydeven, T.

1975-01-01

The need for protective coatings on critical optical surfaces, such as halide crystal windows or lenses used in spectroscopy, has long been recognized. It has been demonstrated that thin, one micron, organic coatings produced by polymerization of flourinated monomers in low temperature gas discharge (plasma) exhibit very high degrees of moisture resistence, e.g., hundreds of hours protection for cesium iodide vs. minutes before degradation sets in for untreated surfaces. The index of refraction of these coatings is intermediate between that of the halide substrate and air, a condition for anti-reflection, another desirable property of optical coatings. Thus, the organic coatings not only offer protection, but improved transmittance as well. The polymer coating is non-absorbing over the range 0.4 to 40 microns with an exception at 8.0 microns, the expected absorption for C-F bonds.

Tribological and Corrosion Properties of Coatings Produced by Plasma Electrolytic Oxidation on the ZA27 Alloy

Science.gov (United States)

Li, Guangyin; Mao, Yifan; Li, Zhijian; Wang, Linlin; DaCosta, Herbert

2018-05-01

In this paper, a continuous and dense coating was deposited on samples of the ZA27 alloy through the plasma electrolytic oxidation (PEO) process to improve its wear and corrosion performance. A nontoxic and environmentally friendly inorganic salt, Na2SiO3, is chosen as electrolytes with different concentrations. The effect of the concentration of Na2SiO3 aqueous solutions on the coating performances was investigated. The coatings with 3Al2O3·2SiO2 (mullite), Zn2SiO4 and Al2O3 (either crystal phase or with some amorphous SiO2 phases) were formed by the PEO processes. It was found that the coating thickness increased with the increase in electrolyte concentration. However, the wear and corrosion resistance performance of the coatings did not improve as the coating's thickness increased. This was due to the fact that the coating produced with electrolytes of 10 g/L has a porous structure with large pore size. Among all the samples, coating produced by 15 g/L Na2SiO3 has the best wear and corrosion resistance, which is attributed to its continuous and dense structure with thickness of about 47 μm.

Tribological and Corrosion Properties of Coatings Produced by Plasma Electrolytic Oxidation on the ZA27 Alloy

Science.gov (United States)

Li, Guangyin; Mao, Yifan; Li, Zhijian; Wang, Linlin; DaCosta, Herbert

2018-04-01

In this paper, a continuous and dense coating was deposited on samples of the ZA27 alloy through the plasma electrolytic oxidation (PEO) process to improve its wear and corrosion performance. A nontoxic and environmentally friendly inorganic salt, Na2SiO3, is chosen as electrolytes with different concentrations. The effect of the concentration of Na2SiO3 aqueous solutions on the coating performances was investigated. The coatings with 3Al2O3·2SiO2 (mullite), Zn2SiO4 and Al2O3 (either crystal phase or with some amorphous SiO2 phases) were formed by the PEO processes. It was found that the coating thickness increased with the increase in electrolyte concentration. However, the wear and corrosion resistance performance of the coatings did not improve as the coating's thickness increased. This was due to the fact that the coating produced with electrolytes of 10 g/L has a porous structure with large pore size. Among all the samples, coating produced by 15 g/L Na2SiO3 has the best wear and corrosion resistance, which is attributed to its continuous and dense structure with thickness of about 47 μm.

Physics properties of TiO_2 films produced by dip-coating technique

International Nuclear Information System (INIS)

Teloeken, A.C.; Alves, A.K.; Berutti, F.A.; Tabarelli, A.; Bergmann, C.P.

2014-01-01

The use of titanium dioxide (TiO_2) as a photocatalyst to produce hydrogen has been of great interest because of their chemical stability, low cost and non-toxicity. TiO_2 occurs in three different crystal forms: rutile, anatase and brokita. Among these, the anatase phase generally exhibits the best photocatalytic behavior, while the rutile phase is the most stable. Among the various techniques of deposition, dip-coating technique produces films with good photocatalytic properties, using simple and inexpensive equipment. In this work TiO_2 films were obtained by dip-coating. The films were characterized using X-ray diffraction, scanning electron microscopy, profilometry, contact angle measurements and photocurrent. The microstructure and physical properties were evaluated in relation of the temperature and the addition of an additive. (author)

Nanocrystalline diamond: In vitro biocompatibility assessment by MG63 and human bone marrow cells cultures.

Science.gov (United States)

Amaral, M; Dias, A G; Gomes, P S; Lopes, M A; Silva, R F; Santos, J D; Fernandes, M H

2008-10-01

Nanocrystalline diamond (NCD) has a great potential for prosthetic implants coating. Nevertheless, its biocompatibility still has to be better understood. To do so, we employed several materials characterization techniques (SEM, AFM, micro-Raman spectroscopy) and cell culture assays using MG63 osteoblast-like and human bone marrow cells. Biochemical routines (MTT assays, Lowry's method, ALP activity) supported by SEM and confocal microscopy characterization were carried out. We used silicon nitride (Si3N4) substrates for NCD coatings based on a previous demonstration of the superior adhesion and tribological performance of these NCD coated ceramics. Results demonstrate an improved human osteoblast proliferation and the stimulation of differentiated markers, like ALP activity and matrix mineralization, compared with standard polystyrene tissue culture plates. The nanometric featuring of NCD, associated to its chemical affinity are key points for bone regeneration purposes.

Beryllium coating produced by evaporation-condensation method and some their properties

Energy Technology Data Exchange (ETDEWEB)

Pepekin, G.I.; Anisimov, A.B.; Chernikov, A.S.; Mozherinn, S.I.; Pirogov, A.A. [SRI SIA Lutch., Podolsk (Russian Federation)

1998-01-01

The method of vacuum evaporation-condensation for deposition of beryllium coatings on metal substrates, considered in the paper, side by side with a plasma-spray method is attractive fon ITER application. In particular this technique may be useful for repair the surface of eroded tiles which is operated in a strong magnetic field. The possibility of deposition of beryllium coatings with the rate of layer growth 0.1-0.2 mm/h is shown. The compatibility of beryllium coating with copper or stainless steel substrate is provided due to intermediate barrier. The results of examination of microstructure, microhardness, porosity, thermal and physical properties and stability under thermal cycling of beryllium materials are presented. The value of thermal expansion coefficient and thermal conductivity of condensed beryllium are approximately the same as for industrial grade material produced by powder mettalurgy technique. However, the condensed beryllium has higher purity (up to 99.9-99.99 % wt.). (author)

The Consortium for NCD Prevention and Control in Sub-Saharan Africa (CNCD-Africa): from concept to practice.

Science.gov (United States)

Amuyunzu-Nyamongo, Mary; Owuor, Jared O; Blanchard, Claire

2013-12-01

CNCD-Africa was established in July 2009 in response to and in recognition of the continuously increasing burden of diseases such as injuries, non-communicable diseases (NCDs) and mental health in low- and middle-income countries, and specifically in countries of sub-Saharan Africa. CNCD-Africa aims to comprehensively address specific and common objectives while building capacity in the region to prevent and control NCDs. With support from key partners and funders, and a keen interest in opportunities to address NCDs from health promotion and equity perspectives, the Consortium has excelled in four key areas: convening; knowledge generation and sharing; advocacy; and networking. However, the path to successful and sustainable efforts remains laden with challenges and barriers. Retaining interest of network partners through flagship efforts and continued efforts to ascertain support from local and international partners with interest in NCDs across the region remain essential to CNCD-Africa core activities. A key lesson learnt from the early years of CNCD-Africa is that existing regional platforms can and should be used to showcase what is being done locally, and to share best practices and best-buys. In addition, partnerships and stakeholder involvement have been key for CNCD-Africa and are essential to NCD action. Sustaining such partnerships requires incentives for the various partners to keep actively involved in NCD action. This can be achieved through joint inception, project planning, implementation, monitoring and evaluation. Another ingredient for success seems to be innovative financing for NCD efforts, which is possible through the establishment and sustaining of regional and global partnerships that are robust, locally relevant and respond to country needs.

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

Stainless steel coatings produced through atmospheric plasma spraying study of in flight powder behavior and coating structure

International Nuclear Information System (INIS)

Denoirjean, A.; Denoirjean, P.; Fauchais, P.; Labbe, J.C.; Khan, A.A.

2005-01-01

The Stainless Steel coatings deposited through Atmospheric Plasma Spraying over mild steel surface present an interest from commercial point of view, especially for the applications where corrosion resistance or inertness towards severe environment is required. Atmospheric Plasma Spraying is fast and relatively less expensive choice as compared to Vacuum Plasma Spraying, the only limitation being the extremely reactive nature of metallic powders used. A study of the behaviour of metallic powders within an Atmospheric Plasma Jet is presented in view of better understanding and eventual improvement in coating properties. Metallic powder particles show very interesting features when individual particles are collected after passing them through a DC Blown Arc Thermal Plasma Jet under Atmospheric Pressure. The spraying was carried out under air which makes the significance of these results even more interesting from the industrial point of view. Proper control of Spraying Parameters can help produce Stainless Steel coatings of reasonably low porosity and a typical lamellar microstructure. The results of SEM, AFM and XRD are discussed. A strange oxidation phenomenon under highly non equilibrium conditions is observed. (author)

Effect of nitrogen-doped carbon dots on the anticorrosion properties of waterborne epoxy coatings

Science.gov (United States)

Ren, Siming; Cui, Mingjun; Zhao, Haichao; Wang, Liping

2018-06-01

In this work, nitrogen-doped carbon dots (NCDs) are prepared by solvothermal method and the effect of NCDs on the anticorrosion property of waterborne epoxy (EP) is investigated. Scanning probe microscopy results show that the size of the NCDs is about 4–6 nm. In addition, the anticorrosion property of NCD-incorporated waterborne epoxy coatings is investigated via electrochemical techniques and scanning electron microscopy. Electrochemical results demonstrate that the impedance modulus of 2.0% NCDs/EP is 364 times higher than that of blank EP after 800 h of immersion, indicating significant enhancement in the anticorrosion property of waterborne epoxy coating. The reason is that NCDs with lots of surface functional groups can connect with waterborne epoxy to suppress enlargement of the pores, and reduce the diffusion of oxygen in the coating, thus cutting off the connection between the substrate and oxygen, and delaying corrosion of the substrate.

Method to produce catalytically active nanocomposite coatings

Science.gov (United States)

Erdemir, Ali; Eryilmaz, Osman Levent; Urgen, Mustafa; Kazmanli, Kursat

2016-02-09

A nanocomposite coating and method of making and using the coating. The nanocomposite coating is disposed on a base material, such as a metal or ceramic; and the nanocomposite consists essentially of a matrix of an alloy selected from the group of Cu, Ni, Pd, Pt and Re which are catalytically active for cracking of carbon bonds in oils and greases and a grain structure selected from the group of borides, carbides and nitrides.

Method to produce catalytically active nanocomposite coatings

Energy Technology Data Exchange (ETDEWEB)

Erdemir, Ali; Eryilmaz, Osman Levent; Urgen, Mustafa; Kazmanli, Kursat

2017-12-19

A nanocomposite coating and method of making and using the coating. The nanocomposite coating is disposed on a base material, such as a metal or ceramic; and the nanocomposite consists essentially of a matrix of an alloy selected from the group of Cu, Ni, Pd, Pt and Re which are catalytically active for cracking of carbon bonds in oils and greases and a grain structure selected from the group of borides, carbides and nitrides.

Glycosaminoglycan-resistant and pH-sensitive lipid-coated DNA complexes produced by detergent removal method.

Science.gov (United States)

Lehtinen, Julia; Hyvönen, Zanna; Subrizi, Astrid; Bunjes, Heike; Urtti, Arto

2008-10-21

Cationic polymers are efficient gene delivery vectors in in vitro conditions, but these carriers can fail in vivo due to interactions with extracellular polyanions, i.e. glycosaminoglycans (GAG). The aim of this study was to develop a stable gene delivery vector that is activated at the acidic endosomal pH. Cationic DNA/PEI complexes were coated by 1,2-dioleylphosphatidylethanolamine (DOPE) and cholesteryl hemisuccinate (CHEMS) (3:2 mol/mol) using two coating methods: detergent removal and mixing with liposomes prepared by ethanol injection. Only detergent removal produced lipid-coated DNA complexes that were stable against GAGs, but were membrane active at low pH towards endosome mimicking liposomes. In relation to the low cellular uptake of the coated complexes, their transfection efficacy was relatively high. PEGylation of the coated complexes increased their cellular uptake but reduced the pH-sensitivity. Detergent removal was thus a superior method for the production of stable, but acid activatable, lipid-coated DNA complexes.

Process for producing a coating composition. [electron beam irradiation

Energy Technology Data Exchange (ETDEWEB)

Kimura, T; Harada, H; Kobayashi, S; Nakamoto, H; Sunano, K

1968-07-19

An easily hardenable acrylic coating composition is produced by irradiation with low energy electron beams to economize the industrial application of the composition. A polymer with molecular weights in the 5,000 to 500,000 range is composed of 1 to 40% by weight of a vinyl monomer containing a glycidyl radical, 30 to 99% of a methacrylic monomer and 0 to 69% of other copolymerizable vinyl monomers. This polymer dissolves in a monomer containing at least 30% of an acrylic monomer and 70% of other vinyl monomers. The reaction takes place between 0.1 to 1.0 mole of vinyl monomer containing a carboxyl radical and one mole of glycidyl radical in the solution. In an embodiment, 17.5% by weight of glycidyl methacrylate and 82.5% of alkyl acrylate are polymerized in suspension in the presence of a catalyst to form a bead like polymer with molecular weights in the 5,000 to 500,000 range. After 120 parts of the bead like polymer are dissolved in 180 parts of the acrylic monomer in the presence of a polymerization inhibitor by heating, 22 parts of ..cap alpha.., ..beta..- unsaturated monocarboxylic acid are added to the solution to react with the glycidyl radical, whereby a non-solvent type coating material containing the polymer having a vinyl radical side chain is produced. In the place of the catalyst, electron beams can be used at an energy level of 0.1 to 20 MeV. The dose rate may be in the range of 0.1 to 2.0 Mrad/sec.

Bone ingrowth potential of electron beam and selective laser melting produced trabecular-like implant surfaces with and without a biomimetic coating.

Science.gov (United States)

Biemond, J E; Hannink, G; Verdonschot, N; Buma, P

2013-03-01

The bone ingrowth potential of trabecular-like implant surfaces produced by either selective laser melting (SLM) or electron beam melting (EBM), with or without a biomimetic calciumphosphate coating, was examined in goats. For histological analysis and histomorphometry of bone ingrowth depth and bone implant contact specimens were implanted in the femoral condyle of goats. For mechanical push out tests to analyse mechanical implant fixation specimens were implanted in the iliac crest. The follow up periods were 4 (7 goats) and 15 weeks (7 goats). Both the SLM and EBM produced trabecular-like structures showed a variable bone ingrowth after 4 weeks. After 15 weeks good bone ingrowth was found in both implant types. Irrespective to the follow up period, and the presence of a coating, no histological differences in tissue reaction around SLM and EBM produced specimens was found. Histological no coating was detected at 4 and 15 weeks follow up. At both follow up periods the mechanical push out strength at the bone implant interface was significantly lower for the coated SLM specimens compared to the uncoated SLM specimens. The expected better ingrowth characteristics and mechanical fixation strength induced by the coating were not found. The lower mechanical strength of the coated specimens produced by SLM is a remarkable result, which might be influenced by the gross morphology of the specimens or the coating characteristics, indicating that further research is necessary.

Combustion chemical vapor desposited coatings for thermal barrier coating systems

Energy Technology Data Exchange (ETDEWEB)

Hampikian, J.M.; Carter, W.B. [Georgia Institute of Technology, Atlanta, GA (United States)

1995-10-01

The new deposition process, combustion chemical vapor deposition, shows a great deal of promise in the area of thermal barrier coating systems. This technique produces dense, adherent coatings, and does not require a reaction chamber. Coatings can therefore be applied in the open atmosphere. The process is potentially suitable for producing high quality CVD coatings for use as interlayers between the bond coat and thermal barrier coating, and/or as overlayers, on top of thermal barrier coatings.

miR-488 determines coat pigmentation by down-regulating the pigment-producing gene pro-opiomelanocortin.

Science.gov (United States)

Wang, H; Ma, S; Xue, L; Li, Y; Wang, J; He, X; Zhu, Z; Dong, C

2016-10-31

Coat color is a key economic trait in wool- and fur-producing animals. Coat color is controlled by complex mechanisms. Pro-opiomelanocortin (POMC) is a gene involved in pigment formation. Previous studies suggested that miR-488 might target the POMC mRNA. This study aimed to determine whether miR-488 could affect coat color by regulating POMC and to explore the regulatory roles of miR-488 on coat color in mammals. A dual fluorescence report vector containing the 3'-UTR of POMC was built to determine whether miR-488 could post-transcriptionally regulate POMC expression. Then, a eukaryotic vector expressing miR-488 was built and transfected into mouse keratinocytes to confirm the regulatory mechanism in vitro. Compared with gray mice, the expression of POMC mRNA was 3.36-fold higher in black mice and 1.29-fold higher in brown mice. The results showed that miR-488 could control mice coat color by combining with the 3'-UTR seed sequence of POMC mRNA to achieve the degradation of POMC mRNA, therefore playing a role in POMC expression. This study revealed the roles of miR-488 in animal coat color and enriches our knowledge about the determination of coat color in mammals.

"They just come, pick and go." The Acceptability of Integrated Medication Adherence Clubs for HIV and Non Communicable Disease (NCD) Patients in Kibera, Kenya.

Science.gov (United States)

Venables, Emilie; Edwards, Jeffrey K; Baert, Saar; Etienne, William; Khabala, Kelly; Bygrave, Helen

2016-01-01

The number of people on antiretroviral therapy (ART) for the long-term management of HIV in low- and middle-income countries (LMICs) is continuing to increase, along with the prevalence of Non-Communicable Diseases (NCDs). The need to provide large volumes of HIV patients with ART has led to significant adaptations in how medication is delivered, but access to NCD care remains limited in many contexts. Medication Adherence Clubs (MACs) were established in Kibera, Kenya to address the large numbers of patients requiring chronic HIV and/or NCD care. Stable NCD and HIV patients can now collect their chronic medication every three months through a club, rather than through individual clinic appointments. We conducted a qualitative research study to assess patient and health-care worker perceptions and experiences of MACs in the urban informal settlement of Kibera, Kenya. A total of 106 patients (with HIV and/or other NCDs) and health-care workers were purposively sampled and included in the study. Ten focus groups and 19 in-depth interviews were conducted and 15 sessions of participant observation were carried out at the clinic where the MACs took place. Thematic data analysis was conducted using NVivo software, and coding focussed on people's experiences of MACs, the challenges they faced and their perceptions about models of care for chronic conditions. MACs were considered acceptable to patients and health-care workers because they saved time, prevented unnecessary queues in the clinic and provided people with health education and group support whilst they collected their medication. Some patients and health-care workers felt that MACs reduced stigma for HIV positive patients by treating HIV as any other chronic condition. Staff and patients reported challenges recruiting patients into MACs, including patients not fully understanding the eligibility criteria for the clubs. There were also some practical challenges during the implementation of the clubs, but MACs

TiC Reinforcement Composite Coating Produced Using Graphite of the Cast Iron by Laser Cladding

Directory of Open Access Journals (Sweden)

Yanhui Liu

2016-09-01

Full Text Available In this study, a TiC-reinforced composite coating was produced to improve the wear resistance of a pearlite matrix grey iron using a pre-placed Ti powder by laser cladding. Results of scanning electron microscopy (SEM, X-ray diffractometer (XRD, and energy dispersive X-ray spectroscopy (EDS confirmed that the coating was composed of TiC particles and two kinds of α-Fe phase. The fine TiC particles were only a few microns in size and uniformly distributed on the matrix phase in the composite coating. The microstructure characteristic of the composite coating resulted in the microhardness rising to about 1000 HV0.3 (China GB/T 4342-1991 and the wear resistance significantly increased relative to the substrate. In addition, the fine and homogeneous solidification microstructure without graphite phase in the transition zone led to a good metallurgical bonding and transition between the coating and the substrate. It was of great significance for the cast iron to modify the surface and repair surface defects or surface damage.

TiC Reinforcement Composite Coating Produced Using Graphite of the Cast Iron by Laser Cladding.

Science.gov (United States)

Liu, Yanhui; Qu, Weicheng; Su, Yu

2016-09-30

In this study, a TiC-reinforced composite coating was produced to improve the wear resistance of a pearlite matrix grey iron using a pre-placed Ti powder by laser cladding. Results of scanning electron microscopy (SEM), X-ray diffractometer (XRD), and energy dispersive X-ray spectroscopy (EDS) confirmed that the coating was composed of TiC particles and two kinds of α -Fe phase. The fine TiC particles were only a few microns in size and uniformly distributed on the matrix phase in the composite coating. The microstructure characteristic of the composite coating resulted in the microhardness rising to about 1000 HV0.3 (China GB/T 4342-1991) and the wear resistance significantly increased relative to the substrate. In addition, the fine and homogeneous solidification microstructure without graphite phase in the transition zone led to a good metallurgical bonding and transition between the coating and the substrate. It was of great significance for the cast iron to modify the surface and repair surface defects or surface damage.

The corrosion resistance of 140MXC, 530AS and 560AS coatings produced by thermal spraying

Directory of Open Access Journals (Sweden)

Edwin Alexis López Covaleda

2013-01-01

Full Text Available Three commercial materials were deposited using electric arc thermal spraying: 140MXC (with Fe, W, Cr, Nb, 530AS (AISI 1015 steel and 560AS (AISI 420 steel on AISI 4340 steel. The aim of this paper was to evaluate the best strategy for improving a coating-substrate system’s corrosion resistance, using the following combinations: homogeneous single coatings, bilayers consisting of 530AS or 560AS under 140MXC and 140MXC + 530AS and 140MXC + 560AS coatings deposited simultaneously. The coatings were characterised using optical microscopy, scanning electron microscopy and X-ray diffraction. Corrosion resistance was evaluated through potentiodynamic polarisation and hardness by using the Vickers test. Corrosion resistance depends on the amount of microstructure defects, the deposition strategy and the alloy elements. However, corrosion resistance was similar in single coatings of 140MXC and bilayers, having -630 V corrosion potential and 708 nA corrosion current. The details and corrosion mechanism of the coatings so produced are described in this paper.

Optimization of Ni-Based WC/Co/Cr Composite Coatings Produced by Multilayer Laser Cladding

Directory of Open Access Journals (Sweden)

Andrea Angelastro

2013-01-01

Full Text Available As a surface coating technique, laser cladding (LC has been developed for improving wear, corrosion, and fatigue properties of mechanical components. The main advantage of this process is the capability of introducing hard particles such as SiC, TiC, and WC as reinforcements in the metallic matrix such as Ni-based alloy, Co-based alloy, and Fe-based alloy to form ceramic-metal composite coatings, which have very high hardness and good wear resistance. In this paper, Ni-based alloy (Colmonoy 227-F and Tungsten Carbides/Cobalt/Chromium (WC/Co/Cr composite coatings were fabricated by the multilayer laser cladding technique (MLC. An optimization procedure was implemented to obtain the combination of process parameters that minimizes the porosity and produces good adhesion to a stainless steel substrate. The optimization procedure was worked out with a mathematical model that was supported by an experimental analysis, which studied the shape of the clad track generated by melting coaxially fed powders with a laser. Microstructural and microhardness analysis completed the set of test performed on the coatings.

Assembly of an Oxalate Decarboxylase Produced under σK Control into the Bacillus subtilis Spore Coat

Science.gov (United States)

Costa, Teresa; Steil, Leif; Martins, Lígia O.; Völker, Uwe; Henriques, Adriano O.

2004-01-01

Over 30 polypeptides are synthesized at various times during sporulation in Bacillus subtilis, and they are assembled at the surface of the developing spore to form a multilayer protein structure called the coat. The coat consists of three main layers, an amorphous undercoat close to the underlying spore cortex peptidoglycan, a lamellar inner layer, and an electron-dense striated outer layer. The product of the B. subtilis oxdD gene was previously shown to have oxalate decarboxylase activity when it was produced in Escherichia coli and to be a spore constituent. In this study, we found that OxdD specifically associates with the spore coat structure, and in this paper we describe regulation of its synthesis and assembly. We found that transcription of oxdD is induced during sporulation as a monocistronic unit under the control of σK and is negatively regulated by GerE. We also found that localization of a functional OxdD-green fluorescent protein (GFP) at the surface of the developing spore depends on the SafA morphogenetic protein, which localizes at the interface between the spore cortex and coat layers. OxdD-GFP localizes around the developing spore in a cotE mutant, which does not assemble the spore outer coat layer, but it does not persist in spores produced by the mutant. Together, the data suggest that OxdD-GFP is targeted to the interior layers of the coat. Additionally, we found that expression of a multicopy allele of oxdD resulted in production of spores with increased levels of OxdD that were able to degrade oxalate but were sensitive to lysozyme. PMID:14973022

Composite superconducting wires produced by rapid coating in Bi-Sr-Ca-Cu-O metal oxide system

International Nuclear Information System (INIS)

Grozav, A.D.; Konopko, L.A.; Leoporda, N.I.

1989-01-01

Method for producing superconducting composite wires by dip coating of copper wires in metal-oxide BiSrCaCu 2 O x melt is developed. The thickness of the coating is regulated by the change of dip rate, melt viscosity and by the number of passages through the melt. Wire annealing at 700-800 deg C leads to the production of two phases, one of them being superconducting with T c =80K

Halloysite nanotubes-titanium dioxide as a solid-phase microextraction coating combined with negative corona discharge-ion mobility spectrometry for the determination of parathion.

Science.gov (United States)

Saraji, Mohammad; Jafari, Mohammad Taghi; Mossaddegh, Mehdi

2016-07-05

Halloysite nanotubes-titanium dioxide (HNTs-TiO2) as a biocompatible environmentally friendly solid-phase microextraction (SPME) fiber coating was prepared. HNTs-TiO2 was chemically coated on the surface of a fused-silica fiber using a sol-gel process. Parathion as an organophosphorus pesticide was selected as a model compound to investigate the extraction efficiency of the fiber. The extracted analyte was detected by negative corona discharge-ion mobility spectrometer (NCD-IMS). The effective parameters on the extraction efficiency, such as salt effect, extraction temperature and extraction time were investigated and optimized. The extraction efficiency of HNTs-TiO2 fiber was compared with bare-silica (sol-gel based coating without HNTs-TiO2), HNTs, carbon nanotubes and commercial SPME fibers (PA, PDMS, and PDMS-DVB). The HNTs-TiO2 fiber showed highest extraction efficiency among the studied fibers. The intra- and inter-day relative standard deviations were found to be 4.3 and 6.3%, respectively. The limit of detection and limit of quantification values were 0.03 and 0.1 μg L(-1), respectively. The dynamic range of the method was in the range of 0.1-25 μg L(-1). The spiking recoveries were between 85 (±9) and 97 (±6). The SPME-HNTs-TiO2 combined with NCD-IMS was successfully applied for the determination of parathion in apple, strawberry, celery and water samples. Copyright © 2016 Elsevier B.V. All rights reserved.

Novel Chemical Process for Producing Chrome Coated Metal

OpenAIRE

Pelar, Christopher; Greenaway, Karima; Zea, Hugo; Wu, Chun-Hsien; Luhrs, Claudia C.; Phillips, Jonathan

2018-01-01

The article of record as published may be found at http://dx.doi.org/10.3390/ma11010078 This work demonstrates that a version of the Reduction Expansion Synthesis (RES) process, Cr-RES, can create a micron scale Cr coating on an iron wire. The process involves three steps. I. A paste consisting of a physical mix of urea, chrome nitrate or chrome oxide, and water is prepared. II. An iron wire is coated by dipping. III. The coated, and dried, wire is heated to ~800 ◦C for 10 min in a tube fu...

Microstructure and microhardness characterization of Cr{sub 3}C{sub 2}-SiC coatings produced by the plasma transferred arc method

Energy Technology Data Exchange (ETDEWEB)

Islak, Serkan [Kastamonu Univ. (Turkey). Cide Rifat Ilgaz Vocational High School; Eski, Oezkan [Kastamonu Univ. (Turkey). Kastamonu Vocational High School; Buytoz, Soner [Firat Univ., Elazig (Turkey). Dept. of Metallurgy and Materials Engineering; Karagoez, Muzaffer [Bartin Univ. (Turkey). Dept. of Metallurgical and Materials Engineering; Stokes, Joseph [Dublin City Univ. (Ireland). School of Mechanical and Manufacturing Engineering

2012-07-01

The purpose of this work was to investigate the coatings made of Cr{sub 3}C{sub 2} and SiC powder manufactured on AISI 304 stainless steel applied by the plasma transferred arc (PTA) welding process. SiC content in the produced coated layer was varied between 0-100 wt. % and the effect of SiC concentration on the microstructure and hardness of the coating was measured experimentally. SEM analyses revealed that the composite coatings had a homogeneous, nonporous, and crack-free microstructure. Dendrites and interdendrite eutectics formed on the coating layer, subject to the temperature gradient and the solidification ratio. There was a significant increase in the hardness of coating layers with the effect of the {gamma}-(Fe,Ni), Cr{sub 7}C{sub 3}, Cr{sub 23}C{sub 6}, Fe{sub 5}C{sub 2}, Cr{sub 3}Si, CrSi{sub 2}, Fe{sub 0.64}Ni{sub 0.36}, CFe{sub 15.1}, C-(Fe,Cr)-Si phases formed in the microstructure. In comparison to the substrate, the microhardness of the coatings produced by PTA were 2.5-3.5 times harder. (orig.)

Traditional local medicines in the republic of Palau and non-communicable diseases (NCD), signs of effectiveness.

Science.gov (United States)

Graz, Bertrand; Kitalong, Christopher; Yano, Victor

2015-02-23

The aim of this survey was to describe which traditional medicines (TM) are most commonly used for non-communicable diseases (NCD - diabetes, hypertension related to excess weight and obesity) in Pacific islands and with what perceived effectiveness. NCD, especially prevalent in the Pacific, have been subject to many public health interventions, often with rather disappointing results. Innovative interventions are required; one hypothesis is that some local, traditional approaches may have been overlooked. The method used was a retrospective treatment-outcome study in a nation-wide representative sample of the adult population (about 15,000 individuals) of the Republic of Palau, an archipelago of Micronesia. From 188 respondents (61% female, age 16-87, median 48,), 30 different plants were used, mostly self-prepared (69%), or from a traditional healer (18%). For excess weight, when comparing the two most frequent plants, Morinda citrifolia L. was associated with more adequate outcome than Phaleria nishidae Kaneh. (P=0.05). In case of diabetes, when comparing Phaleria nishidae (=Phaleria nisidai) and Morinda citrifolia, the former was statistically more often associated with the reported outcome "lower blood sugar" (P=0.01). Statistical association between a plant used and reported outcome is not a proof of effectiveness or safety, but it can help select plants of interest for further studies, e.g. through a reverse pharmacology process, in search of local products which may have a positive impact on population health. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

A novel technique for producing antibody-coated microprobes using a thiol-terminal silane and a heterobifunctional crosslinker.

Science.gov (United States)

Routh, V H; Helke, C J

1997-02-01

Antibody-coated microprobes are used to measure neuropeptide release in the central nervous system. Although they are not quantitative, they provide the most precise spatial resolution of the location of in vivo release of any currently available method. Previous methods of coating antibody microprobes are difficult and time-consuming. Moreover, using these methods we were unable to produce evenly coated antibody microprobes. This paper describes a novel method for the production of antibody microprobes using thiol-terminal silanes and the heterobifunctional crosslinker, 4-(4-N-maleimidophenyl)butyric acid hydrazide HCl 1/2 dioxane (MPBH). Following silation, glass micropipettes are incubated with antibody to substance P (SP) that has been conjugated to MPBH. This method results in a dense, even coating of antibody without decreasing the biological activity of the antibody. Additionally, this method takes considerably less time than previously described methods without sacrificing the use of antibody microprobes as micropipettes. The sensitivity of the microprobes for SP is in the picomolar range, and there is a linear correlation between the log of SP concentration (M) and B/B0 (r2 = 0.98). The microprobes are stable for up to 3 weeks when stored in 0.1 M sodium phosphate buffer with 50 mM NaCl (pH 7.4) at 5 degrees C. Finally, insertion into the exposed spinal cord of an anesthetized rat for 15 min produces no damage to the antibody coating.

Use of gamma-irradiation technology in combination with edible coating to produce shelf-stable foods

International Nuclear Information System (INIS)

Ouattara, B.; Sabato, S.F.; Lacroix, M.

2002-01-01

This research was undertaken to determine the effectiveness of low-dose gamma-irradiation combined with edible coatings to produce shelf-stable foods. Three types of commercially distributed food products were investigated: precooked shrimps, ready to cook pizzas, and fresh strawberries. Samples were coated with various formulations of protein-based solutions and irradiated at total doses between 0 and 3 kGy. Samples were stored at 4 deg. C and evaluated periodically for microbial growth. Sensorial analysis was also performed using a nine-point hedonic scale to evaluate the organoleptic characteristics (odor, taste and appearance). The results showed significant (p≤0.05) combined effect of gamma-irradiation and coating on microbial growth (APCs and Pseudomonas putida). The shelf-life extension periods ranged from 3 to 10 days for shrimps and from 7 to 20 days for pizzas, compared to uncoated/unirradiated products. No significant (p>0.05) detrimental effect of gamma-irradiation on sensorial characteristics (odor, taste, appearance) was observed. In strawberries, coating with irradiated protein solutions resulted in significant reduction of the percentage of mold contamination

TiO2-SiO2 Coatings with a Low Content of AuNPs for Producing Self-Cleaning Building Materials

Directory of Open Access Journals (Sweden)

Manuel Luna

2018-03-01

Full Text Available The high pollution levels in our cities are producing a significant increase of dust on buildings. An application of photoactive coatings on building materials can produce buildings with self-cleaning surfaces. In this study, we have developed a simple sol-gel route for producing Au-TiO2/SiO2 photocatalysts with application on buildings. The gold nanoparticles (AuNPs improved the TiO2 photoactivity under solar radiation because they promoted absorption in the visible range. We varied the content of AuNPs in the sols under study, in order to investigate their effect on self-cleaning properties. The sols obtained were sprayed on a common building stone, producing coatings which adhere firmly to the stone and preserve their aesthetic qualities. We studied the decolourization efficiency of the photocatalysts under study against methylene blue and against soot (a real staining agent for buildings. Finally, we established that the coating with an intermediate Au content presented the best self-cleaning performance, due to the role played by its structure and texture on its photoactivity.

Influence of the reuse of the electrolytic solution on the properties of hydroxyapatite coatings produced by plasma electrolytic oxidation of grade 4 titanium

Energy Technology Data Exchange (ETDEWEB)

Antonio, Cesar A.; Rangel, Elidiane Cipriano; Cruz, Nilson Cristino, E-mail: cesar.augustoa@hotmail.com [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Sorocaba, SP (Brazil)

2016-07-01

Full text: Plasma electrolytic oxidation (PEO) is a process able to produce oxide coatings on light metals, such as Al, Ti, V, Mg, Ta and Nb. In this technique, the application of a voltage, in the range of hundreds of volts, between the sample and a cathode immersed in an electrolyte solution produces electrical fields intense enough to breakdown the insulating oxide layer on the sample surface giving rise to micro electric sparks[1]. These micro-arcs can locally melt the substrate alloying it with elements in the electrolyte solution [2]. In this work PEO has been used to produce coatings with high concentration of hydroxyapatite on Grade 4 titanium disks. The treatments were performed in a 1 liter stainless steel tank. The tank wall was used as the cathode and the coatings were produced during 120 s using calcium acetate and sodium glycerophosphate water solutions as electrolyte. The samples were biased with 480 V pulses with frequency and duty cycle of 100 Hz and 60%, respectively. Using profilometry, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction it has been evaluated the influence of the number of reuses of the solution on the coating properties. The coating produced contains around 85% of HA and it has not been observed any significant changes in their properties when the same solution was reused up to 5 times. [1] A.L. Yerokhin, X. Nie, A. Leyland, A. Matthews, Surf. Coat. Technol. 130 (2000) 195 206. [2] C. A. Antonio, N. C. Cruz, et al. Materials Research. 17(6) 2014; 1427-1433. (author)

Characterization of hard coatings produced by laser cladding using laser-induced breakdown spectroscopy technique

Energy Technology Data Exchange (ETDEWEB)

Varela, J.A.; Amado, J.M.; Tobar, M.J.; Mateo, M.P.; Yañez, A.; Nicolas, G., E-mail: gines@udc.es

2015-05-01

Highlights: • Chemical mapping and profiling by laser-induced breakdown spectroscopy (LIBS) of coatings produced by laser cladding. • Production of laser clads using tungsten carbide (WC) and nickel based matrix (NiCrBSi) powders. • Calibration by LIBS of hardfacing alloys with different WC concentrations. - Abstract: Protective coatings with a high abrasive wear resistance can be obtained from powders by laser cladding technique, in order to extend the service life of some industrial components. In this work, laser clad layers of self-fluxing NiCrBSi alloy powder mixed with WC powder have been produced on stainless steel substrates of austenitic type (AISI 304) in a first step and then chemically characterized by laser-induced breakdown spectroscopy (LIBS) technique. With the suitable laser processing parameters (mainly output power, beam scan speed and flow rate) and powders mixture proportions between WC ceramics and NiCrBSi alloys, dense pore free layers have been obtained on single tracks and on large areas with overlapped tracks. The results achieved by LIBS technique and applied for the first time to the analysis of laser clads provided the chemical composition of the tungsten carbides in metal alloy matrix. Different measurement modes (multiple point analyses, depth profiles and chemical maps) have been employed, demonstrating the usefulness of LIBS technique for the characterization of laser clads based on hardfacing alloys. The behavior of hardness can be explained by LIBS maps which evidenced the partial dilution of some WC spheres in the coating.

Utilization of calcite produced in Turkey for paper coating

Directory of Open Access Journals (Sweden)

Hüdaverdi Eroğlu

2002-03-01

Full Text Available Calcium carbonate is one of the coating pigments widely used in paper industry. Especially, in recent years calcium carbonate filler has gained high importance in alkaline pulping. In Turkey industry actually imports calcium carbonate; whereas, there are rich calcite reservoirs in the country. In this study two different types of domestic ground (GCC calcite samples were used. Physical and chemical properties of calcite samples were tested firstly. CaCO3 percentages of both samples were 97.3 % and 97.6 % (min. 95 % CaCO3. MgCO3 and Fe2O3 percentages were within the desired limits. Brightness values were 95.5 % and 94.5 % and yellowness 1.1 % and 1.5 % elrepho. These values also were within the requested limits. Under 2 microns particle size and over 10 microns particle size fractions were 95 % and 89 % (min. 80 and 1 % and 2 % (max. 2 respectively. Dry matter rates were between 40 %-65 %, for the pilot plant-coating machine. During the preparation of coating color calcium carbonate has been used together with kaolin. The ratios of calcium carbonate to kaolin were 30/70, 40/60, 50/50, 60/40, 70/30, 100/0. In coating color preparation latex was used as a binder because of its wide applications. Latex percentages were 11, 12, and 13 %. Coated papers were glossed and physically tested. As a result, both calcium carbonate samples were found suitable for using in coating color preparation. By the utilization of domestic calcium carbonate in coated paper production, there will be foreign currencies saving.

Increased charge storage capacity of titanium nitride electrodes by deposition of boron-doped nanocrystalline diamond films

DEFF Research Database (Denmark)

Meijs, Suzan; McDonald, Matthew; Sørensen, Søren

2015-01-01

The aim of this study was to investigate the feasibility of depositing a thin layer of boron-doped nanocrystalline diamond (B-NCD) on titanium nitride (TiN) coated electrodes and the effect this has on charge injection properties. The charge storage capacity increased by applying the B-NCD film...

Study of radioactivity diffusion for bitumen-coated blocks produced by an industrial coating plant

International Nuclear Information System (INIS)

Rodier, J.; Lefillatre, G.

1969-01-01

The solidification by bitumen of chemical coprecipitation sludges from the Marcoule waste treatment station has been studied in the laboratory and has led to the construction of an industrial coating plant. The quality of the coated material obtained has been controlled by the lixiviation test carried out with ordinary water and with sea-water on 45 ml laboratory samples and on industrial coated blocks of 150 litres. Tests on blocks of such a size have necessitated the installation of three special tanks. Two, each of 2000 litres capacity, contain ordinary and sea-water which was continuously recycled at a rate of 2.5 cm/hr and renewed periodically. In the third tank having a capacity of 11000 litres, the coated block was buried in earth and sprinkled with ordinary water with a view to studying the migration of radioelements in soil. The results of these tests confirm those obtained during the laboratory experiments. (authors) [fr

Effect of Boron on Microstructure and Microhardness Properties of Mo-Si-B Based Coatings Produced Via TIG Process

Directory of Open Access Journals (Sweden)

Islak S.

2016-09-01

Full Text Available In this study, Mo-Si-B based coatings were produced using tungsten inert gas (TIG process on the medium carbon steel because the physical, chemical, and mechanical properties of these alloys are particularly favourable for high-temperature structural applications. It is aimed to investigate of microstructure and microhardness properties of Mo-Si-B based coatings. Optical microscopy (OM, X-ray diffraction (XRD and scanning electron microscopy (SEM were used to characterize the microstructures of Mo-Si-B based coatings. The XRD results showed that microstructure of Mo–Si–B coating consists of α-Mo, α-Fe, Mo2B, Mo3Si and Mo5SiB2 phases. It was reported that the grains in the microstructure were finer with increasing amounts of boron which caused to occur phase precipitations in the grain boundary. Besides, the average microhardness of coatings changed between 735 HV0.3 and 1140 HV0.3 depending on boron content.

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

Energy Technology Data Exchange (ETDEWEB)

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

2013-01-15

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

Osteogenic cell differentiation on H-terminated and O-terminated nanocrystalline diamond films

Directory of Open Access Journals (Sweden)

Liskova J

2015-01-01

Full Text Available Jana Liskova,1 Oleg Babchenko,2 Marian Varga,2 Alexander Kromka,2 Daniel Hadraba,1 Zdenek Svindrych,1 Zuzana Burdikova,1 Lucie Bacakova1 1Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic; 2Institute of Physics, Academy of Sciences of the Czech Republic, Prague, Czech Republic Abstract: Nanocrystalline diamond (NCD films are promising materials for bone implant coatings because of their biocompatibility, chemical resistance, and mechanical hardness. Moreover, NCD wettability can be tailored by grafting specific atoms. The NCD films used in this study were grown on silicon substrates by microwave plasma-enhanced chemical vapor deposition and grafted by hydrogen atoms (H-termination or oxygen atoms (O-termination. Human osteoblast-like Saos-2 cells were used for biological studies on H-terminated and O-terminated NCD films. The adhesion, growth, and subsequent differentiation of the osteoblasts on NCD films were examined, and the extracellular matrix production and composition were quantified. The osteoblasts that had been cultivated on the O-terminated NCD films exhibited a higher growth rate than those grown on the H-terminated NCD films. The mature collagen fibers were detected in Saos-2 cells on both the H-terminated and O-terminated NCD films; however, the quantity of total collagen in the extracellular matrix was higher on the O-terminated NCD films, as were the amounts of calcium deposition and alkaline phosphatase activity. Nevertheless, the expression of genes for osteogenic markers – type I collagen, alkaline phosphatase, and osteocalcin – was either comparable on the H-terminated and O-terminated films or even lower on the O-terminated films. In conclusion, the higher wettability of the O-terminated NCD films is promising for adhesion and growth of osteoblasts. In addition, the O-terminated surface also seems to support the deposition of extracellular matrix proteins and extracellular matrix

Carbon coated Fe, Co and Ni Nanoparticles produced by high pressure CVD and their potential for medical applications

Energy Technology Data Exchange (ETDEWEB)

El-Gendy, A.A.; Ibrahim, E.M.M.; Khavrus, V.; Krupskaya, Y.; Leonhardt, A.; Klingeler, R.; Buechner, B. [Leibniz Institute for Solid State and Materials Research (IFW), Dresden (Germany)

2009-07-01

Fe rate at C, Co rate at C and Ni rate at C nanocapsules have been produced by high pressure chemical vapour deposition (HPCVD). Scanning electron microscopy images prove that most of the particles are coated with carbon. High resolution transmission electron microscopy imaging confirms that these particles have a broad size distribution and a core/shell structure. In addition, individual nanoparticles are found inside a carbon capsule as well as several particles together in one shell. X-ray diffraction confirms the phases and allows calculating the average particle size from the width of the peaks. Our magnetisation studies confirm that the coated particles are ferromagnetic up to 400 K. AC magnetic heating studies have been performed which imply the potential of carbon coated nanomagnets for applications in hyperthermia therapies.

Novel Chemical Process for Producing Chrome Coated Metal

Directory of Open Access Journals (Sweden)

Christopher Pelar

2018-01-01

Full Text Available This work demonstrates that a version of the Reduction Expansion Synthesis (RES process, Cr-RES, can create a micron scale Cr coating on an iron wire. The process involves three steps. I. A paste consisting of a physical mix of urea, chrome nitrate or chrome oxide, and water is prepared. II. An iron wire is coated by dipping. III. The coated, and dried, wire is heated to ~800 °C for 10 min in a tube furnace under a slow flow of nitrogen gas. The processed wires were then polished and characterized, primarily with scanning electron microscopy (SEM. SEM indicates the chrome layer is uneven, but only on the scale of a fraction of a micron. The evidence of porosity is ambiguous. Elemental mapping using SEM electron microprobe that confirmed the process led to the formation of a chrome metal layer, with no evidence of alloy formation. Additionally, it was found that thickness of the final Cr layer correlated with the thickness of the precursor layer that was applied prior to the heating step. Potentially, this technique could replace electrolytic processing, a process that generates carcinogenic hexavalent chrome, but further study and development is needed.

Novel Chemical Process for Producing Chrome Coated Metal.

Science.gov (United States)

Pelar, Christopher; Greenaway, Karima; Zea, Hugo; Wu, Chun-Hsien; Luhrs, Claudia C; Phillips, Jonathan

2018-01-05

This work demonstrates that a version of the Reduction Expansion Synthesis (RES) process, Cr-RES, can create a micron scale Cr coating on an iron wire. The process involves three steps. I. A paste consisting of a physical mix of urea, chrome nitrate or chrome oxide, and water is prepared. II. An iron wire is coated by dipping. III. The coated, and dried, wire is heated to ~800 °C for 10 min in a tube furnace under a slow flow of nitrogen gas. The processed wires were then polished and characterized, primarily with scanning electron microscopy (SEM). SEM indicates the chrome layer is uneven, but only on the scale of a fraction of a micron. The evidence of porosity is ambiguous. Elemental mapping using SEM electron microprobe that confirmed the process led to the formation of a chrome metal layer, with no evidence of alloy formation. Additionally, it was found that thickness of the final Cr layer correlated with the thickness of the precursor layer that was applied prior to the heating step. Potentially, this technique could replace electrolytic processing, a process that generates carcinogenic hexavalent chrome, but further study and development is needed.

Study of ion plating parameters, coating structure, and corrosion protection for aluminum coatings on uranium

International Nuclear Information System (INIS)

Egert, C.M.; Scott, D.G.

1987-01-01

A study of ion-plating parameters (primarily deposition rate and substrate bias voltage), coating structure, and the corrosion protection provided by aluminum coatings on uranium is presented. Ion plating at low temperatures yields a variety of aluminum coating structures on uranium. For example, aluminum coatings produced at high deposition rates and low substrate bias voltages are columnar with voids between columns, as expected for high-rate vapor deposition at low temperatures. On the other hand, low deposition rate and high bias voltage produce a modified coating with a dense, noncolumnar structure. These results are not in agreement with other studies that have found no relationship between deposition rate and coating structure in ion plating. This discrepancy is probably due to the high deposition rates used in these studies. An accelerated, water vapor corrosion test indicates that the columnar aluminum coatings provide some corrosion protection despite their porous nature; however, the dense noncolumnar coatings provide significantly greater protection. These results indicate that ion-plated aluminum coatings produced at low deposition rates and high substrate bias voltages creates dense coating structures that are most effective in protecting uranium from corrosion

Hydroxyapatite coatings produced on commercially pure titanium by micro-arc oxidation

Energy Technology Data Exchange (ETDEWEB)

Huang Yong [College of Materials Science and Engineering, South China University of Technology, Guangzhou 510641 (China); Wang Yingjun [College of Materials Science and Engineering, South China University of Technology, Guangzhou 510641 (China); Ning Chengyun [College of Materials Science and Engineering, South China University of Technology, Guangzhou 510641 (China); Nan Kaihui [College of Materials Science and Engineering, South China University of Technology, Guangzhou 510641 (China); Han Yong [State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China)

2007-09-15

A porous hydroxyapatite (HA) coating on commercially pure titanium was prepared by micro-arc oxidation (MAO) in electrolytic solution containing calcium acetate and {beta}-glycerol phosphate disodium salt pentahydrate ({beta}-GP). The thickness, phase, composition morphology and biocompatibility of the oxide coating were characterized by x-ray diffraction (XRD), electron probe microanalysis (EPMA), scanning electron microscopy (SEM) with an energy dispersive x-ray spectrometer (EDS) and cell culture. The thickness of the MAO film was about 20 {mu}m, and the coating was porous and uneven without any apparent interface to the titanium substrates. The result of XRD showed that the porous coating was made up of HA film. The favorable osteoblast cell affinity gives HA film good biocompatibility. HA coatings are expected to have significant uses for medical applications such as dental implants and artificial bone joints.

Hydroxyapatite coatings produced on commercially pure titanium by micro-arc oxidation.

Science.gov (United States)

Huang, Yong; Wang, Yingjun; Ning, Chengyun; Nan, Kaihui; Han, Yong

2007-09-01

A porous hydroxyapatite (HA) coating on commercially pure titanium was prepared by micro-arc oxidation (MAO) in electrolytic solution containing calcium acetate and beta-glycerol phosphate disodium salt pentahydrate (beta-GP). The thickness, phase, composition morphology and biocompatibility of the oxide coating were characterized by x-ray diffraction (XRD), electron probe microanalysis (EPMA), scanning electron microscopy (SEM) with an energy dispersive x-ray spectrometer (EDS) and cell culture. The thickness of the MAO film was about 20 microm, and the coating was porous and uneven without any apparent interface to the titanium substrates. The result of XRD showed that the porous coating was made up of HA film. The favorable osteoblast cell affinity gives HA film good biocompatibility. HA coatings are expected to have significant uses for medical applications such as dental implants and artificial bone joints.

Hydroxyapatite coatings produced on commercially pure titanium by micro-arc oxidation

International Nuclear Information System (INIS)

Huang Yong; Wang Yingjun; Ning Chengyun; Nan Kaihui; Han Yong

2007-01-01

A porous hydroxyapatite (HA) coating on commercially pure titanium was prepared by micro-arc oxidation (MAO) in electrolytic solution containing calcium acetate and β-glycerol phosphate disodium salt pentahydrate (β-GP). The thickness, phase, composition morphology and biocompatibility of the oxide coating were characterized by x-ray diffraction (XRD), electron probe microanalysis (EPMA), scanning electron microscopy (SEM) with an energy dispersive x-ray spectrometer (EDS) and cell culture. The thickness of the MAO film was about 20 μm, and the coating was porous and uneven without any apparent interface to the titanium substrates. The result of XRD showed that the porous coating was made up of HA film. The favorable osteoblast cell affinity gives HA film good biocompatibility. HA coatings are expected to have significant uses for medical applications such as dental implants and artificial bone joints

High-Performance Epoxy-Resin-Bonded Magnets Produced from the Sm2Fe17Nx Powders Coated by Copper and Zinc Metals

Science.gov (United States)

Noguchi, Kenji; Machida, Ken-ichi; Adachi, Gin-ya

2001-04-01

Fine powders of Sm2Fe17Nx coated with copper metal reduced from CuCl2 and/or zinc metal subsequently derived by photo-decomposition of diethylzinc [Zn(C2H5)2] were prepared, and their magnetic properties were characterized in addition to those of epoxy-resin-bonded magnets produced from the coated powders (Cu/Sm2Fe17Nx, Zn/Sm2Fe17Nx and Zn/Cu/Sm2Fe17Nx). The remanence (Br) and maximum energy product [(\\mathit{BH})max] of double metal-coated Zn/Cu/Sm2Fe17Nx powders were maintained at higher levels than those of single Zn metal-coated Sm2Fe17Nx ones (Zn/Sm2Fe17Nx) even after heat treatment at 673 K since the oxidation resistance and thermal stability were effectively improved by formation of the thick and uniform protection layer on the surface of Sm2Fe17Nx particles. Moreover, the epoxy-resin-bonded magnets produced from the Zn/Cu/Sm2Fe17Nx powders possessed good corrosion resistance in air at 393 K which it resulted in the smaller thermal irreversible flux loss than that of uncoated and single Zn metal-coated Sm2Fe17Nx powders in the temperature range of above 393 K.

Microporous Ti implant compact coated with hydroxyapatite produced by electro-discharge-sintering and electrostatic-spray-deposition.

Science.gov (United States)

Jo, Y J; Kim, Y H; Jo, Y H; Seong, J G; Chang, S Y; Van Tyne, C J; Lee, W H

2014-11-01

A single pulse of 1.5 kJ/0.7 g of atomized spherical Ti powder from 300 μF capacitor was applied to produce the porous-surfaced Ti implant compact by electro-discharge-sintering (EDS). A solid core surrounded by porous layer was self-consolidated by a discharge in the middle of the compact in 122 μsec. Average pore size, porosity, and compressive yield strength of EDS Ti compact were estimated to be about 68.2 μm, 25.5%, and 266.4 MPa, respectively. Coatings with hydroxyapatite (HAp) on the Ti compact were conducted by electrostatic-spray-deposition (ESD) method. As-deposited HAp coating was in the form of porous structure and consisted of HAp particles which were uniformly distributed on the Ti porous structure. By heat-treatment at 700 degrees C, HAp particles were agglomerated each other and melted to form a highly smooth and homogeneous HAp thin film consisted of equiaxed nano-scaled grains. Porous-surfaced Ti implant compacts coated with highly crystalline apatite phase were successfully obtained by using the EDS and ESD techniques.

The erosion performance of particle reinforced metal matrix composite coatings produced by co-deposition cold gas dynamic spraying

Science.gov (United States)

Peat, Tom; Galloway, Alexander; Toumpis, Athanasios; McNutt, Philip; Iqbal, Naveed

2017-02-01

This work reports on the erosion performance of three particle reinforced metal matrix composite coatings, co-deposited with an aluminium binder via cold-gas dynamic spraying. The deposition of ceramic particles is difficult to achieve with typical cold spray techniques due to the absence of particle deformation. This issue has been overcome in the present study by simultaneously spraying the reinforcing particles with a ductile metallic binder which has led to an increased level of ceramic/cermet particles deposited on the substrate with thick (>400 μm) coatings produced. The aim of this investigation was to evaluate the erosion performance of the co-deposited coatings within a slurry environment. The study also incorporated standard metallographic characterisation techniques to evaluate the distribution of reinforcing particles within the aluminium matrix. All coatings exhibited poorer erosion performance than the uncoated material, both in terms of volume loss and mass loss. The Al2O3 reinforced coating sustained the greatest amount of damage following exposure to the slurry and recorded the greatest volume loss (approx. 2.8 mm3) out of all of the examined coatings. Despite the poor erosion performance, the WC-CoCr reinforced coating demonstrated a considerable hardness increase over the as-received AA5083 (approx. 400%) and also exhibited the smallest free space length between adjacent particles. The findings of this study reveal that the removal of the AA5083 matrix by the impinging silicon carbide particles acts as the primary wear mechanism leading to the degradation of the coating. Analysis of the wear scar has demonstrated that the damage to the soft matrix alloy takes the form of ploughing and scoring which subsequently exposes carbide/oxide particles to the impinging slurry.

Morphology of Diamond Layers Grown on Different Facets of Single Crystal Diamond Substrates by a Microwave Plasma CVD in CH4-H2-N2 Gas Mixtures

Directory of Open Access Journals (Sweden)

Evgeny E. Ashkinazi

2017-06-01

Full Text Available Epitaxial growth of diamond films on different facets of synthetic IIa-type single crystal (SC high-pressure high temperature (HPHT diamond substrate by a microwave plasma CVD in CH4-H2-N2 gas mixture with the high concentration (4% of nitrogen is studied. A beveled SC diamond embraced with low-index {100}, {110}, {111}, {211}, and {311} faces was used as the substrate. Only the {100} face is found to sustain homoepitaxial growth at the present experimental parameters, while nanocrystalline diamond (NCD films are produced on other planes. This observation is important for the choice of appropriate growth parameters, in particular, for the production of bi-layer or multilayer NCD-on-microcrystalline diamond (MCD superhard coatings on tools when the deposition of continuous conformal NCD film on all facet is required. The development of the film morphology with growth time is examined with SEM. The structure of hillocks, with or without polycrystalline aggregates, that appear on {100} face is analyzed, and the stress field (up to 0.4 GPa within the hillocks is evaluated based on high-resolution mapping of photoluminescence spectra of nitrogen-vacancy NV optical centers in the film.

Method of producing carbon coated nano- and micron-scale particles

Science.gov (United States)

Perry, W. Lee; Weigle, John C; Phillips, Jonathan

2013-12-17

A method of making carbon-coated nano- or micron-scale particles comprising entraining particles in an aerosol gas, providing a carbon-containing gas, providing a plasma gas, mixing the aerosol gas, the carbon-containing gas, and the plasma gas proximate a torch, bombarding the mixed gases with microwaves, and collecting resulting carbon-coated nano- or micron-scale particles.

Quality of Coated Particles : Physical - Mechanical Characterization of Polymeric Film Coatings

NARCIS (Netherlands)

Perfetti, G.

2012-01-01

All coated particle producers, when applying the coating layer(s) would like to know precisely what is the best coating system to use in order to answer customer’s requests. It is, therefore, of very high relevance for many industries, to have a clear understanding of what are the parameters I need

Thermal stability of double-ceramic-layer thermal barrier coatings with various coating thickness

International Nuclear Information System (INIS)

Dai Hui; Zhong Xinghua; Li Jiayan; Zhang Yanfei; Meng Jian; Cao Xueqiang

2006-01-01

Double-ceramic-layer (DCL) coatings with various thickness ratios composed of YSZ (6-8 wt.% Y 2 O 3 + ZrO 2 ) and lanthanum zirconate (LZ, La 2 Zr 2 O 7 ) were produced by the atmospheric plasma spraying. Chemical stability of LZ in contact with YSZ in DCL coatings was investigated by calcining powder blends at different temperatures. No obvious reaction was observed when the calcination temperature was lower than 1250 deg. C, implying that LZ and YSZ had good chemical applicability for producing DCL coating. The thermal cycling test indicate that the cycling lives of the DCL coatings are strongly dependent on the thickness ratio of LZ and YSZ, and the coatings with YSZ thickness between 150 and 200 μm have even longer lives than the single-layer YSZ coating. When the YSZ layer is thinner than 100 μm, the DCL coatings failed in the LZ layer close to the interface of YSZ layer and LZ layer. For the coatings with the YSZ thickness above 150 μm, the failure mainly occurs at the interface of the YSZ layer and the bond coat

Aluminum nitride and nanodiamond thin film microstructures

Energy Technology Data Exchange (ETDEWEB)

Knoebber, Fabian; Bludau, Oliver; Roehlig, Claus-Christian; Williams, Oliver; Sah, Ram Ekwal; Kirste, Lutz; Cimalla, Volker; Lebedev, Vadim; Nebel, Christoph; Ambacher, Oliver [Fraunhofer-Institute for Applied Solid State Physics, Freiburg (Germany)

2010-07-01

In this work, aluminum nitride (AlN) and nanocrystalline diamond (NCD) thin film microstructures have been developed. Freestanding NCD membranes were coated with a piezoelectrical AlN layer in order to build tunable micro-lens arrays. For the evaluation of the single material quality, AlN and NCD thin films on silicon substrates were fabricated using RF magnetron sputtering and microwave chemical vapor deposition techniques, respectively. The crystal quality of AlN was investigated by X-ray diffraction. The piezoelectric constant d{sub 33} was determined by scanning laser vibrometry. The NCD thin films were optimized with respect to surface roughness, mechanical stability, intrinsic stress and transparency. To determine the mechanical properties of the materials, both, micromechanical resonator and membrane structures were fabricated and measured by magnetomotive resonant frequency spectroscopy and bulging experiments, respectively. Finally, the behavior of AlN/NCD heterostructures was modeled using the finite element method and the first structures were characterized by piezoelectrical measurements.

Improved mechanical properties of Ni-rich Ni3Al coatings produced by EB-PVD for repairing single crystal blades

Institute of Scientific and Technical Information of China (English)

Jing-Yong Sun; Yan-Ling Pei; Shu-Suo Li; Hu Zhang; Sheng-Kai Gong

2017-01-01

Active control of turbine blade tip clearance for aircraft engine continues to be a concern in engine operation,because turbine blades are subjected to wear and therefore cause an increasing tip clearance between the rotating blades and the shroud and also reduce the engine efficiency.In this work,a Ni-rich Ni3Al coating with γ'/γtwo-phase microstructure was deposited by electron beam physical vapor deposition (EB-PVD),which worked as repairing the worn blade tips of single crystal blades.Nb molten pool was used to increase the molten pool temperature and thus to enhance the deposition rate.The microstructures and mechanical properties can be modified by the deposition temperatures and the following heat treatments.All coatings consist of γ'and γ phases.At deposition temperature of 600 ℃,a dense microstructure can be achieved to produce a coating with grain size of ～ 1 μm and microhardness of ～HV 477.After being heated for 4 h at a temperature of 1,100 ℃,the coatings have a more uniform microstructure,and microhardness maintains at a high level of ～ HV 292.Effect of Hf and Zr on EB-PVD Ni3Al repair coating will be further investigated.

Ni-YSZ graded coatings produced by dipping

International Nuclear Information System (INIS)

Ferrari, B.; Moreno, R.

2004-01-01

A new colloidal processing route for the shaping of a graded Ni-YSZ composite for applications in SOFC devices is described. A Ni foil is coated by Ni/YSZ layers by dipping in aqueous suspensions with an organic binder. Behind the metal-ceramic layers introduced to improve adhesion, an outer thin layer of nanosized YSZ is formed by electrophoretic deposition. (Abstract Copyright [2004], Wiley Periodicals, Inc.)

Microstructure and functional properties of the TiNi- and CuAl-based SMA thin films and coats produced by PVD technique

International Nuclear Information System (INIS)

Kolomytsev, V.; Musienko, R.; Nevdacha, V.; Panarin, V.; Pasko, A.; Cesari, E.; Segui, C.; Humbeeck, J. van

2000-01-01

The TiNi- and CuAl-based shape memory alloy thin films and wear/corrosion resistant surface coats have been produced by the ion-plasma deposition method with an arc dispersion of the cathode/target. This technique was widely used for production of the coats from a sprayed pure metal or a single-phase alloy. We have offered to use this process for dispersion of the heterophase alloys like shape memory alloys. The arguments for choosing of this technique are discussed with respect to creation of the conditions for preservation not only chemical composition, but also phase structure of an alloy in a covering, thus the shape memory/superelastic effects to be kept in a coat. (orig.)

Synthesis and evaluation of MgF2 coatings by chemical conversion on magnesium alloys for producing biodegradable orthopedic implants of temporary use

International Nuclear Information System (INIS)

Casanova, P Y; Jaimes, K J; Parada, N J; Viejo, F; Hernández-Barrios, C A; Aparicio, M; Coy, A E

2013-01-01

The aim of the present work was the synthesis of biodegradable MgF 2 coatings by chemical conversion on the commercial Elektron 21 and AZ91D magnesium alloys, in aqueous HF solutions for different concentrations and temperatures. The chemical composition and morphology of the coatings were analyzed by scanning electron microscopy (SEM-EDX) and X-ray diffraction (XRD). On the other hand, their corrosion behavior was evaluated by gravimetric and electrochemical measurements in Hank's solution at 37°C for different immersion times. The experimental results revealed that chemical conversion in HF produced MgF 2 coatings which corrosion resistance was enhanced by increasing the HF concentration. Further, the microstructure and composition of the base alloy played a key role on the growth and degradation mechanisms of the MgF 2 coatings

Molybdenum plasma spray powder, process for producing said powder, and coating made therefrom

International Nuclear Information System (INIS)

Lafferty, W.D.; Cheney, R.F.; Pierce, R.H.

1979-01-01

Plasma spray powders of molybdenum particles containing 0.5 to 15 weight percent oxygen and obtained by reacting molybdenum particles with oxygen or oxides in a plasma, form plasma spray coatings exhibiting hardness comparable to flame sprayed coatings formed from molybdenum wire and plasma coatings of molybdenum powders. Such oxygen rich molybdenum powders may be used to form wear resistant coatings, such as for piston rings. (author)

Coated Aerogel Beads

Science.gov (United States)

Littman, Howard (Inventor); Plawsky, Joel L. (Inventor); Paccione, John D. (Inventor)

2014-01-01

Methods and apparatus for coating particulate material are provided. The apparatus includes a vessel having a top and a bottom, a vertically extending conduit having an inlet in the vessel and an outlet outside of the vessel, a first fluid inlet in the bottom of the vessel for introducing a transfer fluid, a second fluid inlet in the bottom of the vessel for introducing a coating fluid, and a fluid outlet from the vessel. The method includes steps of agitating a material, contacting the material with a coating material, and drying the coating material to produce a coated material. The invention may be adapted to coat aerogel beads, among other materials. A coated aerogel bead and an aerogel-based insulation material are also disclosed.

Method for fluidizing and coating ultrafine particles, device for fluidizing and coating ultrafine particles

Science.gov (United States)

Li, Jie; Liu, Yung Y

2015-01-20

The invention provides a method for dispersing particles within a reaction field, the method comprising confining the particles to the reaction field using a standing wave. The invention also provides a system for coating particles, the system comprising a reaction zone; a means for producing fluidized particles within the reaction zone; a fluid to produce a standing wave within the reaction zone; and a means for introducing coating moieties to the reaction zone. The invention also provides a method for coating particles, the method comprising fluidizing the particles, subjecting the particles to a standing wave; and contacting the subjected particles with a coating moiety.

Nanocrystalline diamond--an excellent platform for life science applications.

Science.gov (United States)

Kloss, Frank R; Najam-Ul-Haq, Muhammed; Rainer, Matthias; Gassner, Robert; Lepperdinger, Günter; Huck, Christian W; Bonn, Günther; Klauser, Frederik; Liu, Xianjie; Memmel, Norbert; Bertel, Erminald; Garrido, Jose A; Steinmüller-Nethl, Doris

2007-12-01

Nanocrystalline diamond (NCD) has recently been successfully utilized in a variety of life science applications. NCD films are favorable and salubrious substrates for cells during cultivation. Therefore NCD has also been employed in tissue engineering strategies. NCD as reported in this contribution was grown by means of a modified hot-filament chemical vapor deposition technique, which results in less than 3% sp2-hybridization and yields grain sizes of 5-20 nm. After production the NCD surface was rather hydrophobic, however it could be efficiently refined to exhibit more hydrophilic properties. Changing of the surface structure was found to be an efficient means to influence growth and differentiation capacity of a variety of cells. The particular needs for any given cell type has to be proven empirically. Yet flexible features of NCD appear to be superior to plastic surfaces which can be hardly changed in quality. Besides its molecular properties, crystal structural peculiarities of NCD appear to influence cell growth as well. In our attempt to facilitate, highly specialized applications in biomedicine, we recently discovered that growth factors can be tightly bound to NCD by mere physisorption. Hence, combination of surface functionalization together with further options to coat NCD with any kind of three-dimensional structure opens up new avenues for many more applications. In fact, high through-put protein profiling of early disease stages may become possible from serum samples, because proteins bound to NCD can now be efficiently analyzed by MALDI/TOF-MS. Given these results, it is to be presumed that the physical properties and effective electrochemical characteristics of NCD will allow tailoring devices suitable for many more diagnostic as well as therapeutic applications.

Effect of complexing agents and pH on microstructure and tribological properties of Co-W coatings produced by double pulse electrodeposition

International Nuclear Information System (INIS)

Su Fenghua; Liu Cansen; Huang Ping

2012-01-01

The Co-W coatings were produced by double pulse electrodeposition from aqueous bath with cobalt sulphate and sodium tungstate. Effect of complexing agent and pH value in the plating bath on the microstructure, morphology and hardness of the electrodeposited Co-W coatings were investigated using an X-ray diffraction (XRD), scanning electron microscope (SEM) and a Vickers hardness tester, respectively. The friction and wear properties of the Co-W coatings deposited from different baths were evaluated with a ball-on-disk UMT-3MT tribometer. The correlation among the electrodepositing condition that varied with the complexing agent or pH value, the microstructure and the tribological properties of the deposited Co-W coatings were discussed. The results show that the complexing agent and pH value significantly affect the microstructure and tribological properties of the electrodeposited Co-W coatings. The sodium citrate is the best complexing agent to improve the tribological properties of the electrodeposited Co-W coatings at pH 6.0, followed by the sodium gluconate. The Co-W coatings electrodeposited from the near neutral bath can obtain better tribological properties than those deposited from strong acid or strong alkaline bath. The differences of the tribological properties for Co-W coatings from different baths were attributed to their different hardness, crystal structure and morphological characterizations, which can be optimized by the electrodepositing condition, i.e., the complexing agent and pH value in bath.

Structure, properties and applications of TiN coatings produced by sputter ion plating

International Nuclear Information System (INIS)

Rickerby, D.S.

1988-01-01

The potential beneficial effects that wear-resistant coatings have on engineering surfaces depends upon their ability to remain adherent with the treated component. This paper concentrates on the process of sputter ion plating, a simple dc glow discharge sputtering system operating in soft vacuum, and relates the properties of titanium nitride coatings to the degree of ion polishing (substrate bias) which is utilised during deposition. Substrate bias was identified as the most important system parameter since it allowed for some stress relaxation within the coating via its influence on porosity levels in the coating microstructure. The influence that this has on coating adhesion is discussed. The internal stress is a combination of intrinsic growth stresses and thermal mismatch stresses with the latter tending to dominate as substrate bias is increased. In addition to substrate bias, the role that titanium interlayers and substrate cleaning play in improving the adhesion of titanium nitride coatings is discussed, and the potential benefits highlighted. In the last part of the paper some applications of titanium nitride coating are described -it will be shown that increase in component life is by no means the only criterion which should be considered when judging the success, or otherwise, of a coated component. (author)

Experimental setup for producing tungsten coated graphite tiles using plasma enhanced chemical vapor deposition technique for fusion plasma applications

International Nuclear Information System (INIS)

Chauhan, Sachin Singh; Sharma, Uttam; Choudhary, K.K.; Sanyasi, A.K.; Ghosh, J.; Sharma, Jayshree

2013-01-01

Plasma wall interaction (PWI) in fusion grade machines puts stringent demands on the choice of materials in terms of high heat load handling capabilities and low sputtering yields. Choice of suitable material still remains a challenge and open topic of research for the PWI community. Carbon fibre composites (CFC), Beryllium (Be), and Tungsten (W) are now being considered as first runners for the first wall components of future fusion machines. Tungsten is considered to be one of the suitable materials for the job because of its superior properties than carbon like low physical sputtering yield and high sputter energy threshold, high melting point, fairly high re-crystallization temperature, low fuel retention capabilities, low chemical sputtering with hydrogen and its isotopes and most importantly the reparability with various plasma techniques both ex-situ and in-situ. Plasma assisted chemical vapour deposition is considered among various techniques as the most preferable technique for fabricating tungsten coated graphite tiles to be used as tokamak first wall and target components. These coated tiles are more favourable compared to pure tungsten due to their light weight and easier machining. A system has been designed, fabricated and installed at SVITS, Indore for producing tungsten coated graphite tiles using Plasma Enhanced Chemical Vapor Deposition (PE-CVD) technique for Fusion plasma applications. The system contains a vacuum chamber, a turbo-molecular pump, two electrodes, vacuum gauges, mass analyzer, mass flow controllers and a RF power supply for producing the plasma using hydrogen gas. The graphite tiles will be put on one of the electrodes and WF6 gas will be inserted in a controlled manner in the hydrogen plasma to achieve the tungsten-coating with WF6 dissociation. The system is integrated at SVITS, Indore and a vacuum of the order of 3*10 -6 is achieved and glow discharge plasma has been created to test all the sub-systems. The system design with

Characterization of hard coatings produced by laser cladding using laser-induced breakdown spectroscopy technique

Science.gov (United States)

Varela, J. A.; Amado, J. M.; Tobar, M. J.; Mateo, M. P.; Yañez, A.; Nicolas, G.

2015-05-01

Protective coatings with a high abrasive wear resistance can be obtained from powders by laser cladding technique, in order to extend the service life of some industrial components. In this work, laser clad layers of self-fluxing NiCrBSi alloy powder mixed with WC powder have been produced on stainless steel substrates of austenitic type (AISI 304) in a first step and then chemically characterized by laser-induced breakdown spectroscopy (LIBS) technique. With the suitable laser processing parameters (mainly output power, beam scan speed and flow rate) and powders mixture proportions between WC ceramics and NiCrBSi alloys, dense pore free layers have been obtained on single tracks and on large areas with overlapped tracks. The results achieved by LIBS technique and applied for the first time to the analysis of laser clads provided the chemical composition of the tungsten carbides in metal alloy matrix. Different measurement modes (multiple point analyses, depth profiles and chemical maps) have been employed, demonstrating the usefulness of LIBS technique for the characterization of laser clads based on hardfacing alloys. The behavior of hardness can be explained by LIBS maps which evidenced the partial dilution of some WC spheres in the coating.

Research Priorities for NCD Prevention and Climate Change: An International Delphi Survey.

Science.gov (United States)

Colagiuri, Ruth; Boylan, Sinead; Morrice, Emily

2015-10-16

Climate change and non-communicable diseases (NCDs) are arguably the greatest global challenges of the 21st Century. However, the confluence between them remains under-examined and there is little evidence of a comprehensive, systematic approach to identifying research priorities to mitigate their joint impact. Consequently, we: (i) convened a workshop of academics (n = 25) from the Worldwide Universities Network to identify priority areas at the interface between NCDs and climate change; (ii) conducted a Delphi survey of international opinion leaders in public health and relevant other disciplines; and (iii) convened an expert panel to review and advise on final priorities. Three research areas (water security; transport; conceptualising NCD harms to support policy formation) were listed among the top 10 priorities by >90% of Delphi respondents, and ranked among the top 12 priorities by >60% of respondents who ranked the order of priority. A fourth area (reducing the carbon footprint of cities) was ranked highest by the same >60% of respondents. Our results are consistent with existing frameworks on health and climate change, and extends them by focusing specifically on NCDs. Researching these priorities could progress understanding of climate change and NCDs, and inform global and national policy decisions for mitigating associated harms.

Research Priorities for NCD Prevention and Climate Change: An International Delphi Survey

Directory of Open Access Journals (Sweden)

Ruth Colagiuri

2015-10-01

Full Text Available Climate change and non-communicable diseases (NCDs are arguably the greatest global challenges of the 21st Century. However, the confluence between them remains under-examined and there is little evidence of a comprehensive, systematic approach to identifying research priorities to mitigate their joint impact. Consequently, we: (i convened a workshop of academics (n = 25 from the Worldwide Universities Network to identify priority areas at the interface between NCDs and climate change; (ii conducted a Delphi survey of international opinion leaders in public health and relevant other disciplines; and (iii convened an expert panel to review and advise on final priorities. Three research areas (water security; transport; conceptualising NCD harms to support policy formation were listed among the top 10 priorities by >90% of Delphi respondents, and ranked among the top 12 priorities by >60% of respondents who ranked the order of priority. A fourth area (reducing the carbon footprint of cities was ranked highest by the same >60% of respondents. Our results are consistent with existing frameworks on health and climate change, and extends them by focusing specifically on NCDs. Researching these priorities could progress understanding of climate change and NCDs, and inform global and national policy decisions for mitigating associated harms.

Coated foams, preparation, uses and articles

Science.gov (United States)

Duchane, D.V.; Barthell, B.L.

1982-10-21

Hydrophobic cellular material is coated with a thin hydrophilic polymer skin which stretches tightly over the foam but which does not fill the cells of the foam, thus resulting in a polymer-coated foam structure having a smoothness which was not possible in the prior art. In particular, when the hydrophobic cellular material is a specially chosen hydrophobic polymer foam and is formed into arbitrarily chosen shapes prior to the coating with hydrophilic polymer, inertial confinement fusion (ICF) targets of arbitrary shapes can be produced by subsequently coating the shapes with metal or with any other suitable material. New articles of manufacture are produced, including improved ICF targets, improved integrated circuits, and improved solar reflectors and solar collectors. In the coating method, the cell size of the hydrophobic cellular material, the viscosity of the polymer solution used to coat, and the surface tension of the polymer solution used to coat are all very important to the coating.

Microstructure Characterization of WCCo-Mo Based Coatings Produced Using High Velocity Oxygen Fuel

Directory of Open Access Journals (Sweden)

Serkan Islak

2015-12-01

Full Text Available The present study has been carried out in order to investigate the microstructural properties of WCCo-Mo composite coatings deposited onto a SAE 4140 steel substrate by high velocity oxygen fuel (HVOF thermal spray. For this purpose, the Mo quantity added to the WCCo was changed as 10, 20, 30 and 40 wt. % percents. The coatings are compared in terms of their phase composition, microstructure and hardness. Phase compound and microstructure of coating layers were examined using X-ray diffractometer (XRD and scanning electron microscope (SEM. XRD results showed that WCCo-Mo composite coatings were mainly composed of WC, W2C, Co3W3C, Mo2C, MoO2, Mo and Co phases. The average hardness of the coatings increased with increasing Mo content.

Metallographic techniques for evaluation of Thermal Barrier Coatings produced by Electron Beam Physical Vapor Deposition

International Nuclear Information System (INIS)

Kelly, Matthew; Singh, Jogender; Todd, Judith; Copley, Steven; Wolfe, Douglas

2008-01-01

Thermal Barrier Coatings (TBC) produced by Electron Beam Physical Vapor Deposition (EB-PVD) are primarily applied to critical hot section turbine components. EB-PVD TBC for turbine applications exhibit a complicated structure of porous ceramic columns separated by voids that offers mechanical compliance. Currently there are no standard evaluation methods for evaluating EB-PVD TBC structure quantitatively. This paper proposes a metallographic method for preparing samples and evaluating techniques to quantitatively measure structure. TBC samples were produced and evaluated with the proposed metallographic technique and digital image analysis for columnar grain size and relative intercolumnar porosity. Incorporation of the proposed evaluation technique will increase knowledge of the relation between processing parameters and material properties by incorporating a structural link. Application of this evaluation method will directly benefit areas of quality control, microstructural model development, and reduced development time for process scaling

The analysis of impact of irregularity in radionuclide coating of scaffold on the distribution of absorbed dose produced by grid of microsources

Directory of Open Access Journals (Sweden)

N. A. Nerosin

2015-01-01

Full Text Available The impact of irregularity in radionuclide coating of scaffold on the distribution of absorbed dose produced by grid of microsources was analyzed. On engineering software MATHCAD the program for calculation of absorbed dose produced by grid of microsources was created. To verify this algorithm the calculation model for MCNP code was established and represented the area consisted of soft biological tissue or any other tissue in which the grid of microsources was incorporated. Using the developed system the value of possible systematic irregular coating of radioactivity on the microsource’s core was analyzed. The distribution of activity along the surface of microsource was simulated to create distribution of absorbed dose rate corresponding to experimental data on radiation injury. The obtained model of microsource with irregular distribution of activity was compared to conventional microsource with core coated regularly along the entire area of the silver stem by main dosimetry characteristics. The results showed that even for extremely irregular distribution of activity the distribution of dose rate produced by microsource in the tumor area was not substantially different from dose-rate field obtained for microsource with regularly coated activity. The differences in dose rates (up to 10% in areas which were the nearest to the center of the grid were significantly lower than its decline from center to periphery of the grid. For spatial distribution of absorbed dose for specific configuration of microsource set and tracing of curves of equal level by selected cut-off the program SEEDPLAN was developed. The developed program represents precisely enough the spatial distribution of selected configuration set of microsources using results of calculation data for absorbed dose around the single microsource as basic data and may be used for optimal planning of brachytherapy with microsources. 

Bone ingrowth potential of electron beam and selective laser melting produced trabecular-like implant surfaces with and without a biomimetic coating

NARCIS (Netherlands)

Biemond, J.E.; Hannink, G.; Verdonschot, Nicolaas Jacobus Joseph; Buma, P.

2013-01-01

The bone ingrowth potential of trabecular-like implant surfaces produced by either selective laser melting (SLM) or electron beam melting (EBM), with or without a biomimetic calciumphosphate coating, was examined in goats. For histological analysis and histomorphometry of bone ingrowth depth and

Tough ceramic coatings: Carbon nanotube reinforced silica sol-gel

Science.gov (United States)

López, A. J.; Rico, A.; Rodríguez, J.; Rams, J.

2010-08-01

Silica coatings reinforced with carbon nanotubes were produced via sol-gel route using two mixing techniques of the sol-gel precursors, mechanical and ultrasonic mixing, and dip-coating as deposition process on magnesium alloy substrates. Effective incorporation and distribution of 0.1 wt.% of carbon nanotubes in the amorphous silica matrix of the coatings were achieved using both techniques. Fabrication procedure determines the morphological aspects of the coating. Only mechanical mixing process produced coatings dense and free of defects. Nanoindentation technique was used to examine the influence of the fabrication process in the mechanical features of the final coatings, i.e. indentation fracture toughness, Young's modulus and hardness. A maximum toughening effect of about 24% was achieved in silica coatings reinforced with carbon nanotubes produced by the mechanical mixing route. Scanning electron microscopy investigation revealed that the toughening of these reinforced coatings was mainly due to bridging effect of the reinforcement.

Sol-gel coatings: An alternative route for producing planar optical waveguides

Energy Technology Data Exchange (ETDEWEB)

Rey-Garcia, F.; Gomez-Reino, C. [Unidad Asociada de Optica and Microoptica GRIN (CSIC-ICMA), Departamento de Fisica Aplicada, Escola Universitaria de Optica e Optometria, Universidade de Santiago de Compostela, Campus Sur s/n, E-15782 Santiago de Compostela (Spain); Flores-Arias, M.T., E-mail: maite.flores@usc.es [Unidad Asociada de Optica and Microoptica GRIN (CSIC-ICMA), Departamento de Fisica Aplicada, Escola Universitaria de Optica e Optometria, Universidade de Santiago de Compostela, Campus Sur s/n, E-15782 Santiago de Compostela (Spain); De La Fuente, G.F., E-mail: xerman@unizar.es [Instituto de Ciencia de Materiales de Aragon (CSIC-Universidad de Zaragoza), Maria de Luna 3, E-50018 Zaragoza (Spain); Duran, A. [Instituto de Ceramica y Vidrio (CSIC), Kelsen 5, E-28049, Madrid (Spain); Castro, Y., E-mail: castro@icv.csic.es [Instituto de Ceramica y Vidrio (CSIC), Kelsen 5, E-28049, Madrid (Spain)

2011-09-01

Inorganic and hybrid planar waveguides with different compositions (silica-titania, methacrylate-silica-cerium oxide, zirconia-cerium oxide and silica-zirconia) have been obtained by sol-gel synthesis followed by dip-coating. Soda-lime glass slides and conventional commercial window glass were used as substrates. The thickness and refractive index of the coatings were determined by profilometry and Spectroscopic Ellipsometry. Waveguide efficiency was measured at ca. 70.8% with a He-Ne laser beam, coupled with an optical microscope objective into and out of the waveguiding layer via a double prism configuration. Thicknesses between 150 and 2000 nm, along with refractive index values ranging between 1.45 and {approx} 1.99 ({lambda} = 633 nm) were obtained depending on the sol composition and the dip-coating conditions. This wide range of values allows designing multilayered guides that can be used in a variety of applications.

Sol-gel coatings: An alternative route for producing planar optical waveguides

International Nuclear Information System (INIS)

Rey-Garcia, F.; Gomez-Reino, C.; Flores-Arias, M.T.; De La Fuente, G.F.; Duran, A.; Castro, Y.

2011-01-01

Inorganic and hybrid planar waveguides with different compositions (silica-titania, methacrylate-silica-cerium oxide, zirconia-cerium oxide and silica-zirconia) have been obtained by sol-gel synthesis followed by dip-coating. Soda-lime glass slides and conventional commercial window glass were used as substrates. The thickness and refractive index of the coatings were determined by profilometry and Spectroscopic Ellipsometry. Waveguide efficiency was measured at ca. 70.8% with a He-Ne laser beam, coupled with an optical microscope objective into and out of the waveguiding layer via a double prism configuration. Thicknesses between 150 and 2000 nm, along with refractive index values ranging between 1.45 and ∼ 1.99 (λ = 633 nm) were obtained depending on the sol composition and the dip-coating conditions. This wide range of values allows designing multilayered guides that can be used in a variety of applications.

Charged-particle coating

International Nuclear Information System (INIS)

Johnson, W.L.; Crane, J.K.; Hendricks, C.D.

1980-01-01

Advanced target designs require thicker (approx. 300 μm) coatings and better surface finishes that can be produced with current coating techniques. An advanced coating technique is proposed to provide maximum control of the coating flux and optimum manipulation of the shell during processing. In this scheme a small beam of ions or particles of known incident energy are collided with a levitated spherical mandrel. Precise control of the incident energy and angle of the deposition flux optimizes the control of the coating morphology while controlled rotation and noncontact support of the shell minimizes the possibility of particulate or damage generated defects. Almost infinite variability of the incident energy and material in this process provides increased flexibility of the target designs which can be physically realized

Zinc phosphate conversion coatings

Science.gov (United States)

Sugama, Toshifumi

1997-01-01

Zinc phosphate conversion coatings for producing metals which exhibit enhanced corrosion prevention characteristics are prepared by the addition of a transition-metal-compound promoter comprising a manganese, iron, cobalt, nickel, or copper compound and an electrolyte such as polyacrylic acid, polymethacrylic acid, polyitaconic acid and poly-L-glutamic acid to a phosphating solution. These coatings are further improved by the incorporation of Fe ions. Thermal treatment of zinc phosphate coatings to generate .alpha.-phase anhydrous zinc phosphate improves the corrosion prevention qualities of the resulting coated metal.

for zeolite coating

Directory of Open Access Journals (Sweden)

Carlos Renato Rambo

2006-01-01

Full Text Available Biotemplating is the processing of microcellular ceramics by reproduction of natural morphologies, where the microstructural features of the biotemplate are maintained in the biomorphic ceramic. Different biotemplates with distinct pore anatomies were used to produce biomorphic supports for the zeolite coating: wood, cardboard, sea-sponge and sisal. The biomorphic ceramics were produced by distinguished processing routes: Al-gas infiltration-reaction, liquid-metal infiltration, dip-coating and sol-gel synthesis, in order to produce nitrides, carbides and oxides, depending on the processing conditions. The zeolite coating was performed by hydrothermal growth of MFI-type (Silicalite-1 and ZSM-5 zeolite crystals onto the internal pore walls of the biomorphic templates. The final biomorphic ceramic-zeolite composites were physically characterized, evaluated in terms of their gas adsorption capabilities and correlated to their microstructure and specific pore anatomy. The combination of the properties of the biomorphic ceramics with the adsorption properties of zeolites results in materials with distinct properties as potential candidates for adsorption and catalytic applications due to their characteristic porosity, molecular sieving capabilities and high thermo-mechanical strength.

Absorptive coating for aluminum solar panels

Science.gov (United States)

Desmet, D.; Jason, A.; Parr, A.

1979-01-01

Method for coating forming coating of copper oxide from copper component of sheet aluminum/copper alloy provides strong durable solar heat collector panels. Copper oxide coating has solar absorption characteristics similar to black chrome and is much simpler and less costly to produce.

Laser cladding of bioactive glass coatings.

Science.gov (United States)

Comesaña, R; Quintero, F; Lusquiños, F; Pascual, M J; Boutinguiza, M; Durán, A; Pou, J

2010-03-01

Laser cladding by powder injection has been used to produce bioactive glass coatings on titanium alloy (Ti6Al4V) substrates. Bioactive glass compositions alternative to 45S5 Bioglass were demonstrated to exhibit a gradual wetting angle-temperature evolution and therefore a more homogeneous deposition of the coating over the substrate was achieved. Among the different compositions studied, the S520 bioactive glass showed smoother wetting angle-temperature behavior and was successfully used as precursor material to produce bioactive coatings. Coatings processed using a Nd:YAG laser presented calcium silicate crystallization at the surface, with a uniform composition along the coating cross-section, and no significant dilution of the titanium alloy was observed. These coatings maintain similar bioactivity to that of the precursor material as demonstrated by immersion in simulated body fluid. Copyright 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

High-performance characteristics of the bonded magnets produced from the Sm2 Fe17 Nx powder stabilized by photo-induced zinc metal coatings

International Nuclear Information System (INIS)

Machida, K.; Izumi, H.; Shiomi, A.; Iguchi, M.; Adachi, G.

1996-01-01

Finely and uniformly ground powders of Sm 2 Fe 17 N x were stabilized by surface-coating with the zinc metal produced from Zn (C 2 H 5 ) 2 . The epoxy resin-bonded magnets produced from the Zn/Sm 2 Fe 17 N x composite powder provided high-performance permanent magnetic characteristics: (BH)max=∼ 176 kJm -3 . (author)

A MICROPOROUS COATING OR STRUCTURE AND A PROCESS FOR PRODUCING IT

DEFF Research Database (Denmark)

2008-01-01

A microporous coating or structure is established as a thin metallic layer by deposition of one or more alloys on a metallic substrate, each of said alloys consisting of two or more phases, one of which can be selectively dissolved in a solution that will not significantly attack the other phase...... or phases. Such microporous coatings or structures are useful in the production of various product types, such as fuel cells, catalysts, microfilters, heat exchangers, micro-components and heat transfer devices....

Corrosion resistance of Al-based coatings in flowing Pb–15.7Li produced by aluminum electrodeposition from ionic liquids

Directory of Open Access Journals (Sweden)

Sven-Erik Wulf

2016-12-01

Full Text Available Reduced activation ferritic–martensitic steels are intended to serve as structural materials in different blanket designs, e.g. HCLL, DCLL and WCLL. In these designs the material is supposed to be in direct contact with the flowing liquid breeder material Pb–15.7Li at an operating temperature of up to 550°C. These conditions will lead to severe corrosion attack of the steel and high corrosion rates of up to 400µm per year are reported in the literature. To avoid or reduce corrosion Al-based corrosion barriers were developed in the last years by using electrochemical techniques to deposit aluminum. Until now two processes have been developed. The first one, so called ECA process, is based on volatile toluene electrolytes. Long-term corrosion experiments on these coatings indicated reduced corrosion rates compared to bare Eurofer steel in flowing Pb–15.7Li. However, these Fe–Al scales showed inhomogeneous corrosion attack of the corrosion barrier itself. In this study the improved ECX process was applied to produce Al-based coatings. The short-term corrosion behavior of such barrier coatings was analyzed for up to 4000h by diameter measurements and metallographic examinations. The investigation revealed uniform corrosion in comparison to inhomogeneous attack in case of ECA coated samples and reduced corrosion rates of around 20µm/a even for low exposure times of 4000h.

Automated coating procedures to produce poly(ethylene glycol) brushes in fused-silica capillaries

DEFF Research Database (Denmark)

Poulsen, Nicklas N.; Østergaard, Jesper; Petersen, Nickolaj J.

2017-01-01

. Flexible and reliable approaches for preventing unwanted protein adsorption in separation science are thus in high demand. We therefore present new coating approaches based on an automated in-capillary surface initiated atom transfer radical polymerization process (covalent coating) as well...... as by electrostatically adsorbing a pre-synthesized polymer leading to functionalized molecular brushes. The electroosmotic flow was measured following each step of the covalent coating procedure providing a detailed characterization and quality control. Both approaches resulted in good fouling resistance against...

Evaluating impacts of organizational intelligence in creating competitive strategy in companies producing powder coating

Directory of Open Access Journals (Sweden)

Somaye Nasiri

2013-03-01

Full Text Available Organizational intelligence (OI plays an important role on creating competitive strategy. This paper measure the effect of OI differentiation through value chain of organizational activities. The proposed study is applied in companies, which are active in the field of producing powder coating. Literature and background of research was reviewed to compile theoretical framework of the research model and after conducting library studies and performing exploratory interviews, important factors influencing OI on various sectors of the organization were extracted. In the same direction, these components were assessed through survey research and questionnaire tool. The proposed study uses structural equation modeling is implemented to study the effects of various factors and the validity of relationship among components was confirmed through a conceptual model.

Effect of coating parameters on the microstructure of cerium oxide conversion coatings

Energy Technology Data Exchange (ETDEWEB)

Johnson, Benedict Y.; Edington, Joe; O' Keefe, Matthew J

2003-11-25

The microstructure and morphology of cerium oxide conversion coatings prepared under different deposition conditions were characterized by transmission electron microscopy (TEM). The coatings were formed by a spontaneous reaction between a water-based solution containing CeCl{sub 3} and aluminum alloy 7075-T6 substrates. Microstructural characterization was performed to determine the crystallinity of the coatings and to obtain a better understanding of the deposition parameters on coating microstructure. The results of TEM imaging and electron diffraction analysis indicated that the as-deposited coating was composed of nanocrystalline particles of a previously unreported cerium compound. The particles of the coatings produced using glycerol as an additive were found to be much finer than those of the coatings prepared in the absence of glycerol. This indicates that glycerol may act as a grain refiner and/or growth inhibitor during coating deposition. After deposition, the coated panels were treated for 5 min in a phosphate sealing solution. The sealing treatment converted the as-deposited coating into hydrated cerium phosphate. Panels coated from solutions containing no glycerol followed by phosphate sealing performed poorly in salt fog tests. With glycerol addition, the corrosion resistance of the coatings that were phosphate sealed improved considerably, achieving an average passing rate of 85%.

Effect of Dipping and Vacuum Impregnation Coating Techniques with Alginate Based Coating on Physical Quality Parameters of Cantaloupe Melon.

Science.gov (United States)

Senturk Parreidt, Tugce; Schmid, Markus; Müller, Kajetan

2018-04-01

Edible coating based on sodium alginate solution was applied to fresh-cut cantaloupe melon by dipping and vacuum impregnation coating methods. One aim of this work is to produce more technical information concerning these conventional and novel coating processes. For this purpose, the effect of various coating parameters (dipping time, draining time, time length of the vacuum period, vacuum pressure, atmospheric restoration time) with several levels on physical quality parameters (percentage of weight gain, color, and texture) of noncoated and coated samples were determined in order to define adequate coating process parameters to achieve a successful coating application. Additionally, the effects of dipping and vacuum impregnation processes were compared. Both processes improved the firmness of the melon pieces. However, vacuum impregnation application had higher firmness and weight gain results, and had significant effect (P coating technique and the parameters used significantly affect the physical quality characteristics of coated food products. The work presented produced more technical information concerning dipping and vacuum impregnation coating techniques, along with evaluating the effects of various coating parameters with several levels. The results revealed that vacuum impregnation technique is a successful coating method; however the effects should be carefully assessed for each product. © 2018 Institute of Food Technologists®.

Plasma processed coating of laser fusion targets

International Nuclear Information System (INIS)

Johnson, W.L.; Letts, S.A.; Myers, D.W.; Crane, J.K.; Illige, J.D.; Hatcher, C.W.

1979-01-01

Coatings for laser fusion targets have been deposited in an inductively coupled discharge device by plasma polymerization. Two feed gases were used: perfluoro-2-butene, which produced a fluorocarbon coating (CF 1 3 ) with a density of 1.8 g/cc, and trans-2-butene which produced a hydrocarbon coating (CH 1 3 ) with a density of 1.0 g/cc. Uniform pin-hole free films have been deposited to a thickness of up to 30 μm of fluorocarbon and up to 110 μm of hydrocarbon. The effect of process variables on surface smoothness has been investigated. The basic defect in the coating has been found to result from shadowing by a small surface irregularity in an anisotropic coating flux

A spectroscopic and microstructural study of oxide coatings produced on a Ti–6Al–4V alloy by plasma electrolytic oxidation

International Nuclear Information System (INIS)

Hussein, R.O.; Nie, X.; Northwood, D.O.

2012-01-01

Highlights: ► PEO (plasma electrolytic oxidation) for production of oxide coatings on a Ti–6Al–4V alloy. ► Two different current modes namely pulsed unipolar and bipolar was used. ► Optical emission spectroscopy (OES) was used to characterize the PEO plasma. ► This is the first attempt to characterize spectroscopically the PEO plasma of Ti and its alloys. ► The discharge behavior effect on the formation and structure of the coating was determined. - Abstract: In this study, we have used PEO (plasma electrolytic oxidation) for the production of oxide coatings on a Ti–6Al–4V alloy at two different current modes, namely pulsed unipolar and bipolar. Optical emission spectroscopy (OES) in the visible and near UV band (280–800 nm) was used to characterize the PEO plasma. The emission spectra were recorded and the plasma temperature profile versus processing time was constructed using a line intensity ratios method. The aim of this work was to study the effect of the process parameters, including current mode and pulse duration time, on the plasma characteristics, surface morphology and microstructure and corrosion resistance of oxides grown on Ti–6Al–4V by PEO process. Scanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDS) and X-ray diffraction (XRD) were used to study the coating microstructure, morphology and phase composition. The corrosion resistance of the coated and uncoated samples was examined by potentiodynamic polarization in a 3.5% NaCl solution. It was found that the plasma temperature profiles are significantly influenced by changing the current mode from unipolar to bipolar. The strongest discharges that are initiated at the interface between the substrate and the coating can be reduced or eliminated by using a bipolar current mode. This produces a thinner, denser and more corrosion-resistant coating.

Comprehensive Evaluation of the Properties of Nanocrystalline Diamond Coatings Grown Using CVD with E/H Field Glow Discharge Stabilization

Directory of Open Access Journals (Sweden)

Iu. Nasieka

2015-01-01

Full Text Available The nanocrystalline diamond films (coatings were prepared using the plasma enhanced chemical vapor deposition (PECVD technique. In this method, direct current (DC glow discharge in the crossed E/H fields was used to activate the gas phase. The diamond coatings were deposited from the working gas mixture CH4/H2 with addition of nitrogen in various concentrations. It was ascertained that addition of N2 to the working gas mixture leads to reduction in the sizes of diamond grains as well as to the substantial decrease in the resistivity of the studied films. The electrophysical data are in good agreement with the changes induced by varying the N2 content in the Raman scattering spectra. The increase in the N2 concentration causes significant lowering of the crystalline diamond related peak and increase in the intensity of the peaks related to the sp2-bonded carbon. These changes in the spectra indicate significant disordering of the structure of prepared films and its uniformity in the nanodiamond film volume. With the great possibility, it is associated with a decrease in the sizes of diamond crystalline grains and tendency of NCD film to amorphization.

Magnesium substituted hydroxyapatite formation on (Ti,Mg)N coatings produced by cathodic arc PVD technique.

Science.gov (United States)

Onder, Sakip; Kok, Fatma Nese; Kazmanli, Kursat; Urgen, Mustafa

2013-10-01

In this study, formation of magnesium substituted hydroxyapatite (Ca10-xMgx(PO4)6(OH)2) on (Ti,Mg)N and TiN coating surfaces were investigated. The (Ti1-x,Mgx)N (x=0.064) coatings were deposited on titanium substrates by using cathodic arc physical vapor deposition technique. TiN coated grade 2 titanium substrates were used as reference to understand the role of magnesium on hydroxyapatite (HA) formation. The HA formation experiments was carried out in simulated body fluids (SBF) with three different concentrations (1X SBF, 5X SBF and 5X SBF without magnesium ions) at 37 °C. The coatings and hydroxyapatite films formed were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD) and FTIR Spectroscopy techniques. The energy dispersive X-ray spectroscopy (EDS) analyses and XRD investigations of the coatings indicated that magnesium was incorporated in the TiN structure rather than forming a separate phase. The comparison between the TiN and (Ti, Mg)N coatings showed that the presence of magnesium in TiN structure facilitated magnesium substituted HA formation on the surface. The (Ti,Mg)N coatings can potentially be used to accelerate the HA formation in vivo conditions without any prior hydroxyapatite coating procedure. © 2013.

Development of Bioactive Ceramic Coating on Titanium Alloy substrate for Biomedical Application Using Dip Coating Method

Science.gov (United States)

Asmawi, R.; Ibrahim, M. H. I.; Amin, A. M.; Mustafa, N.; Noranai, Z.

2017-08-01

Bioactive apatite, such as hydroxyapatite ceramic (HA), [Ca10(PO4)6(OH)2] has been extensively investigated for biomedical applications due to its excellent biocompatibility and tissue bioactivity properties. Its bioactivity provides direct bonding to the bone tissue. Because of its similarity in chemical composition to the inorganic matrix of bone, HA is widely used as implant materials for bone. Unfortunately, because of its poor mechanical properties,. this bioactive material is not suitable for load bearing applications. In this study, by the assistance of dip-coating technique, HA coatings were deposited on titanium alloy substrates by employing hydrothermal derived HA powder. The produced coatings then were oven-dried at 130°C for 1 hour and calcined at various temperature over the range of 200-800°C for 1 hour. XRD measurement showed that HA was the only phase present in the coatings. However coatings calcined at 800°C comprised a mixture of HA and tri-calcium phosphate (TCP). FTIR measurement showed the existence of hydroxyl, phosphate, and carbonate bands. PO4 - band became sharper and narrower with the increased of calcination temperature. FESEM observation showed that the coating is polycrystalline with individual particles of nano to submicron size and has an average particle size of 35 nm. The thickness of the coating are direcly propotional with the viscosity of coating slurry. It was shown that the more viscous coating slurry would produce a thicker ceramic coating. Mechanical properties of the coating were measured in term of adhesion strength using a Micro Materials Nano Test microscratch testing machine. The result revealed that the coating had a good adhesion to the titanium alloy substrate.

Mechanical behaviour of Zn-Fe alloy coated mild steel

International Nuclear Information System (INIS)

Panagopoulos, C.N.; Georgiou, E.P.; Agathocleous, P.E.; Giannakopoulos, K.I.

2009-01-01

Zinc alloy coatings containing various amounts of Fe were deposited by electrodeposition technique on a mild steel substrate. The concentration of Fe in the produced alloy coatings ranged from 0 to 14 wt.%, whereas the thickness of the coatings was about 50 μm. Structural and metallurgical characterization of the produced coatings was performed with the aid of X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) techniques. This study aims in investigating the mechanical behaviour of Zn-Fe coated mild steel specimens, as no research investigation concerning the tensile behaviour of Zn alloy coated ferrous alloys has been reported in the past. The experimental results indicated that the ultimate tensile strength of the Zn-Fe coated mild steel was lower than the bare mild steel. In addition, the ductility of the Zn-Fe coated mild steel was found to decrease significantly with increasing Fe content in the coating.

Process to minimize cracking of pyrolytic carbon coatings

Science.gov (United States)

Lackey, Jr., Walter J.; Sease, John D.

1978-01-01

Carbon-coated microspheroids useful as fuels in nuclear reactors are produced with a low percentage of cracked coatings and are imparted increased strength and mechanical stability characteristics by annealing immediately after the carbon coating processes.

Magnesium substituted hydroxyapatite formation on (Ti,Mg)N coatings produced by cathodic arc PVD technique

International Nuclear Information System (INIS)

Onder, Sakip; Kok, Fatma Nese; Kazmanli, Kursat; Urgen, Mustafa

2013-01-01

In this study, formation of magnesium substituted hydroxyapatite (Ca 10−x Mg x (PO 4 ) 6 (OH) 2 ) on (Ti,Mg)N and TiN coating surfaces were investigated. The (Ti 1−x ,Mg x )N (x = 0.064) coatings were deposited on titanium substrates by using cathodic arc physical vapor deposition technique. TiN coated grade 2 titanium substrates were used as reference to understand the role of magnesium on hydroxyapatite (HA) formation. The HA formation experiments was carried out in simulated body fluids (SBF) with three different concentrations (1X SBF, 5X SBF and 5X SBF without magnesium ions) at 37 °C. The coatings and hydroxyapatite films formed were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD) and FTIR Spectroscopy techniques. The energy dispersive X-ray spectroscopy (EDS) analyses and XRD investigations of the coatings indicated that magnesium was incorporated in the TiN structure rather than forming a separate phase. The comparison between the TiN and (Ti, Mg)N coatings showed that the presence of magnesium in TiN structure facilitated magnesium substituted HA formation on the surface. The (Ti,Mg)N coatings can potentially be used to accelerate the HA formation in vivo conditions without any prior hydroxyapatite coating procedure. - Highlights: • Mg incorporated in (Ti,Mg)N coating structure and did not form a separate phase • Mg dissolution in SBF solution facilitated Mg-substituted hydroxyapatite formation • (Ti,Mg)N acted as Mg-source for Mg-substituted hydroxyapatite formation in SBF

Microstructures, mechanical properties and corrosion resistance of Hastelloy C22 coating produced by laser cladding

International Nuclear Information System (INIS)

Wang, Qin-Ying; Zhang, Yang-Fei; Bai, Shu-Lin; Liu, Zong-De

2013-01-01

Highlights: ► Hastelloy C22 coatings were prepared by diode laser cladding technique. ► Higher laser speed resulted in smaller grain size. ► Size-effect played the key role in the hardness measurements by different ways. ► Coating with higher laser scanning speed displayed higher nano-scratch resistance. ► Small grain size was beneficial for improvement of coating corrosion resistance. -- Abstract: The Hastelloy C22 coatings H1 and H2 were prepared by laser cladding technique with laser scanning speeds of 6 and 12 mm/s, respectively. Their microstructures, mechanical properties and corrosion resistance were investigated. The microstructures and phase compositions were studied by metallurgical microscope, scanning electron microscope and X-ray diffraction analysis. The hardness and scratch resistance were measured by micro-hardness and nanoindentation tests. The polarization curves and electrochemical impedance spectroscopy were tested by electrochemical workstation. Planar, cellular and dendritic solidifications were observed in the coating cross-sections. The coatings metallurgically well-bonded with the substrate are mainly composed of primary phase γ-nickel with solution of Fe, W, Cr and grain boundary precipitate of Mo 6 Ni 6 C. The hardness and corrosion resistance of steel substrate are significantly improved by laser cladding Hastelloy C22 coating. Coating H2 shows higher micro-hardness than that of H1 by 34% and it also exhibits better corrosion resistance. The results indicate that the increase of laser scanning speed improves the microstuctures, mechanical properties and corrosion resistance of Hastelloy C22 coating

Microstructure and abrasive wear properties of M(Cr,Fe7C3 carbides reinforced high-chromium carbon coating produced by gas tungsten arc welding (GTAW process

Directory of Open Access Journals (Sweden)

Soner BUYTOZ

2010-01-01

Full Text Available In the present study, high-chromium ferrochromium carbon hypereutectic alloy powder was coated on AISI 4340 steel by the gas tungsten arc welding (GTAW process. The coating layers were analyzed by optical microscopy, X-ray diffraction (XRD, field-emission scanning electron microscopy (FE-SEM, X-ray energy-dispersive spectroscopy (EDS. Depending on the gas tungsten arc welding pa-rameters, either hypoeutectic or hypereutectic microstructures were produced. Wear tests of the coatings were carried out on a pin-on-disc apparatus as function of contact load. Wear rates of the all coating layers were decreased as a function of the loading. The improvement of abrasive wear resistance of the coating layer could be attributed to the high hardness of the hypereutectic M7C3 carbides in the microstruc-ture. As a result, the microstructure of surface layers, hardness and abrasive wear behaviours showed different characteristics due to the gas tungsten arc welding parameters.

Multilayer Ti-Cr-N Coatings Produced by the Vacuum-Arc Deposition

International Nuclear Information System (INIS)

Kunchenko, Yu.V.; Kunchenko, V.V.; Neklyudov, I.M.; Kartmazov, G.N.; Andreev, A.A.

2007-01-01

A possibility is demonstrated for nanolayer TiN x /CrN x coating formation by the method of vacuum-arc deposition on the substrate, which being rotated around the 'Bulat'-type chamber axis intercepts sequentially the plasma flows generated by three evaporators. The model for calculating the coating deposition rate (thickness) was used to determine the geometrical parameters that provide the formation of layer structures in the nanometer range. The variations of phase-structure characteristics, compression microstresses (σ) microhardness (H v ) of the coating formed have been investigated as functions of nitrogen pressure (P N =0.001...1.0 Pa), bias voltage (U=-100...-300 V) and condensation temperature (T C =330...750 degree C) at focusing magnetic field strength H F =0; 35 and 100 Oe. The mentioned field strengths were responsible for the ion current densities (j∼5,8...10 and ≥15 mA/cm 2 ). A nonmonotonic behaviour of H v as a function of condensation temperature and of vacuum annealing temperature has been established. The maximum H v values (∼35...37 GPa) were observed in the 450...500 degree C range

Titanate nanotube coatings on biodegradable photopolymer scaffolds

Energy Technology Data Exchange (ETDEWEB)

Beke, S., E-mail: szabolcs.beke@iit.it [Department of Nanophysics, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genova (Italy); Kőrösi, L. [Department of Biotechnology, Nanophage Therapy Center, Enviroinvest Corporation, Kertváros u. 2, H-7632, Pécs (Hungary); Scarpellini, A. [Department of Nanochemistry, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genova (Italy); Anjum, F.; Brandi, F. [Department of Nanophysics, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genova (Italy)

2013-05-01

Rigid, biodegradable photopolymer scaffolds were coated with titanate nanotubes (TNTs) by using a spin-coating method. TNTs were synthesized by a hydrothermal process at 150 °C under 4.7 bar ambient pressure. The biodegradable photopolymer scaffolds were produced by mask-assisted excimer laser photocuring at 308 nm. For scaffold coating, a stable ethanolic TNT sol was prepared by a simple colloid chemical route without the use of any binding compounds or additives. Scanning electron microscopy along with elemental analysis revealed that the scaffolds were homogenously coated by TNTs. The developed TNT coating can further improve the surface geometry of fabricated scaffolds, and therefore it can further increase the cell adhesion. Highlights: ► Biodegradable scaffolds were produced by mask-assisted UV laser photocuring. ► Titanate nanotube deposition was carried out without binding compounds or additives. ► The titanate nanotube coating can further improve the surface geometry of scaffolds. ► These reproducible platforms will be of high importance for biological applications.

Electron beam-cured coating

International Nuclear Information System (INIS)

Kishi, Naoyuki

1976-01-01

The method for hardening coatings by the irradiation with electron beams is reviewed. The report is divided into seven parts, namely 1) general description and characteristics of electron beam-cured coating, 2) radiation sources of curing, 3) hardening conditions and reaction behaviour, 4) uses and advantages, 5) latest trends of the industry, 6) practice in the field of construction materials, and 7) economy. The primary characteristics of the electron beam hardening is that graft reaction takes place between base resin and coating to produce strong adhesive coating without any pretreatment. A variety of base resins are developed. High class esters of acrylic acid monomers and methacrylic acid monomers are mainly used as dilutants recently. At present, scanning type accelerators are used, but the practical application of the system producing electron beam of curtain type is expected. The dose rate dependence, the repetitive irradiation and the irradiation atmosphere are briefly described. The filed patent applications on the electron beam hardening were analyzed by the officer of Japan Patent Agency. The production lines for coatings by the electron beam hardening in the world are listed. In the electron beam-cured coating, fifty percent of given energy is consumed effectively for the electron beam hardening, and the solvents discharged from ovens and polluting atmosphere are not used, because the paints of high solid type is used. The running costs of the electron beam process are one sixth of the thermal oven process. (Iwakiri, K.)

Laser cladding of wear resistant metal matrix composite coatings

International Nuclear Information System (INIS)

Yakovlev, A.; Bertrand, Ph.; Smurov, I.

2004-01-01

A number of coatings with wear-resistant properties as well as with a low friction coefficient are produced by laser cladding. The structure of these coatings is determined by required performance and realized as metal matrix composite (MMC), where solid lubricant serves as a ductile matrix (e.g. CuSn), reinforced by appropriate ceramic phase (e.g. WC/Co). One of the engineered coating with functionally graded material (FGM) structure has a dry friction coefficient 0.12. Coatings were produced by coaxial injection of powder blend into the zone of laser beam action. Metallographic and tribological examinations were carried out confirming the advanced performance of engineered coatings

Calcium phosphate-based coatings on titanium and its alloys.

Science.gov (United States)

Narayanan, R; Seshadri, S K; Kwon, T Y; Kim, K H

2008-04-01

Use of titanium as biomaterial is possible because of its very favorable biocompatibility with living tissue. Titanium implants having calcium phosphate coatings on their surface show good fixation to the bone. This review covers briefly the requirements of typical biomaterials and narrowly focuses on the works on titanium. Calcium phosphate ceramics for use in implants are introduced and various methods of producing calcium phosphate coating on titanium substrates are elaborated. Advantages and disadvantages of each type of coating from the view point of process simplicity, cost-effectiveness, stability of the coatings, coating integration with the bone, cell behavior, and so forth are highlighted. Taking into account all these factors, the efficient method(s) of producing these coatings are indicated finally.

Investigation of duty cycle effect on corrosion properties of electrodeposited calcium phosphate coatings

Energy Technology Data Exchange (ETDEWEB)

Azem, Funda Ak, E-mail: funda.ak@deu.edu.tr [Dokuz Eylul University, Faculty of Engineering, Department of Metallurgical and Materials Engineering, Buca, 35390 Izmir (Turkey); Delice, Tulay Koc, E-mail: tulaykocdelice@gmail.com [Dokuz Eylul University, The Graduate School of Natural and Applied Sciences, Buca, 35390 Izmir (Turkey); Ungan, Guler, E-mail: gulerungan@hotmail.com [Es Group, Izmir (Turkey); Cakir, Ahmet, E-mail: ahmet.cakir@deu.edu.tr [Dokuz Eylul University, Faculty of Engineering, Department of Metallurgical and Materials Engineering, Buca, 35390 Izmir (Turkey)

2016-11-01

The bioceramic calcium phosphate (CaP) is frequently used for improving bone fixation in titanium medical implants and thus increasing lifetime of the implant. It is known that the application of CaP coatings on metallic implant devices offers the possibility of combining the strength of the metals and the bioactivity of the ceramic materials. Many different techniques are available for producing CaP coatings. Electrochemical deposition method is widely used because of its ease of operation parameters, low temperature requirement, reproducibility and suitability for coating complex structures. This technique allows obtaining CaP coatings which promote bone in growth during the first healing period leading to permanent fixation. Electrochemical pulse technique is an alternative to calcium phosphate deposition techniques usually employed to cover orthopedic or dental titanium implant surfaces. Additionally, pulse electrodeposition technique can produce more uniform and denser CaP coatings on metallic implants. In this study, CaP based coatings were produced by electrochemical pulse technique on Ti6Al4V substrates. The resulting CaP deposits were investigated by means of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Corrosion properties of the CaP coatings were also investigated. The results showed that various duty cycle ranges have remarkably effect on morphology, crystallinity and corrosion properties of the produced CaP coatings. - Highlights: • Electrodeposited CaP based coating were produced by pulse deposition technique. • The pulsed electrodeposited coatings produced under 30% and 50% duty cycles were exhibited better corrosion resistance. • Produced coatings consist of irregular flake-like structure and compact network with fine needles.

Oxidation resistant coatings for ceramic matrix composite components

Energy Technology Data Exchange (ETDEWEB)

Vaubert, V.M.; Stinton, D.P. [Oak Ridge National Lab., TN (United States); Hirschfeld, D.A. [New Mexico Inst. of Mining and Technology, Socorro, NM (United States). Dept. of Materials and Metallurgical Engineering

1998-11-01

Corrosion resistant Ca{sub 0.6}Mg{sub 0.4}Zr{sub 4}(PO{sub 4}){sub 6} (CMZP) and Ca{sub 0.5}Sr{sub 0.5}Zr{sub 4}(PO{sub 4}){sub 6} (CS-50) coatings for fiber-reinforced SiC-matrix composite heat exchanger tubes have been developed. Aqueous slurries of both oxides were prepared with high solids loading. One coating process consisted of dipping the samples in a slip. A tape casting process has also been created that produced relatively thin and dense coatings covering a large area. A processing technique was developed, utilizing a pre-sintering step, which produced coatings with minimal cracking.

Electroless deposition of nickel-boron coatings using low frequency ultrasonic agitation: Effect of ultrasonic frequency on the coatings.

Science.gov (United States)

Bonin, L; Bains, N; Vitry, V; Cobley, A J

2017-05-01

The effect of ultrasound on the properties of Nickel-Boron (NiB) coatings was investigated. NiB coatings were fabricated by electroless deposition using either ultrasonic or mechanical agitation. The deposition of Ni occurred in an aqueous bath containing a reducible metal salt (nickel chloride), reducing agent (sodium borohydride), complexing agent (ethylenediamine) and stabilizer (lead tungstate). Due to the instability of the borohydride in acidic, neutral and slightly alkaline media, pH was controlled at pH 12±1 in order to avoid destabilizing the bath. Deposition was performed in three different configurations: one with a classical mechanical agitation at 300rpm and the other two employing ultrasound at a frequency of either 20 or 35kHz. The microstructures of the electroless coatings were characterized by a combination of optical Microscopy and Scanning Electron Microscope (SEM). The chemistry of the coatings was determined by ICP-AES (Inductively Coupled Plasma - Atomic Emission Spectrometry) after dissolution in aqua regia. The mechanical properties of the coatings were established by a combination of roughness measurements, Vickers microhardness and pin-on-disk tribology tests. Lastly, the corrosion properties were analysed by potentiodynamic polarization. The results showed that low frequency ultrasonic agitation could be used to produce coatings from an alkaline NiB bath and that the thickness of coatings obtained could be increased by over 50% compared to those produced using mechanical agitation. Although ultrasonic agitation produced a smoother coating and some alteration of the deposit morphology was observed, the mechanical and corrosion properties were very similar to those found when using mechanical agitation. Copyright © 2017 Elsevier B.V. All rights reserved.

Characterization of novel nanostructured materials for applications

International Nuclear Information System (INIS)

Klauser, F.

2009-01-01

This thesis presents a characterization of bulk- and surface properties of various (nanoscale) materials with respect to their possible use in applications. The main part of this work is dedicated to nanocrystalline Diamond films (NCD). Other materials include silicon nanoparticle films, gallium-, tungsten-, niobium- and hafnium-oxides as well as commercially available piercing materials. Diamond films of different surface terminations and morphologies were prepared and characterized, in order to realize surfaces with optimized properties for biological and medical applications. It was shown that properly terminated NCD Materials can be used as defined substrates for cell culture and cell-adhesion studies. In view of the use of NCD as coating for medical implants also in-vivo studies on the tissue attachment to differently terminated NCD surfaces were performed. NCD from chemical vapour deposition is a composite material which - in addition to diamond - also contains carbon species in grain boundaries. Thus - besides characterization of bulk properties (as hydrogen- and sp2 content or diamond grain size) - investigation of grain-boundary properties is important for the NCD-based applications presented within this thesis, including an electrochemical sensor, a thin-film acoustic resonator and a surface-plasmon- resonance based sensor. Thin films of silicon nanoparticles were studied by means of XPS-sputter depth profiling with respect to their behaviour under various oxidation conditions, such as exposure to ambient air or to oxygen plasma as well as upon electron irradiation under high-vacuum conditions. The investigation of gallium and tungsten oxides aims at their potential use as model catalysts. Besides a structural characterization, their oxidation and reduction behaviour was studied. Furthermore, a dendritic mixed-oxide system with an enhanced interface area could be prepared. Niobium and hafnium oxides are often used as dielectrics. It was the aim of the

Review of Research Work on Ti-BASED Composite Coatings

Science.gov (United States)

Gabbitas, Brian; Salman, Asma; Zhang, Deliang; Cao, Peng

The service life of industrial components is limited predominantly by Chemical corrosion/mechanical wear. The project is concerned with the investigation of the capability of Ti(Al,O)/Al2O3 coatings to improve the service life of tool steel (H13) used for dies in aluminium high pressure die casting. This paper gives a general review on the research work conducted at the University of Waikato on producing and evaluating the titanium/alumina based composite coatings. The powder feedstocks for making the composite coatings were produced by high energy mechanical milling of a mixture of Al and TiO2 powders in two different molar ratios followed by a thermal reaction process. The feedstocks were then thermally sprayed using a high velocity air-fuel (HVAF) technique on H13 steel substrates to produce a Ti(Al,O)/Al2O3 composite coatings. The performance of the coating was assessed in terms of thermal shock resistance and reaction kinetics with molten aluminium. The composite powders and coatings were characterized using scanning electron microscopy (SEM), optical microscopy and X-ray diffractometry (XRD).

A new titanium based alloy Ti-27Nb-13Zr produced by powder metallurgy with biomimetic coating for use as a biomaterial.

Science.gov (United States)

Mendes, Marcio W D; Ágreda, Carola G; Bressiani, Ana H A; Bressiani, José C

2016-06-01

Titanium alloys are widely used in biomedical applications due to their excellent properties such as high strength, good corrosion resistance and biocompatibility. Titanium alloys with alloying elements such as Nb and Zr are biocompatible and have Young's modulus close to that of human bone. To increase the bioactivity of titanium alloy surfaces is used chemical treatment with NaOH followed by immersion in simulated body fluid (SBF). The purpose of this study was to produce the alloy Ti-27Nb-13Zr with low Young's modulus by powder metallurgy using powders produced by the HDH process. The formation of biomimetic coatings on samples immersed in SBF for 3, 7, 11 and 15 days was evaluated. Characterization of the coating was performed by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and scanning electron microscope. The microstructure and composition of the alloy were determined using SEM and XRD, while the mechanical properties were evaluated by determining the elastic modulus and the Vickers microhardness. The sintered alloys were composed of α and β phases, equiaxed grains and with density around 97.8% of its theoretical density. The Vickers microhardness and elasticity modulus of the alloy were determined and their values indicate that this alloy can be used as a biomaterial. Analysis of the coating revealed the presence of calcium phosphate layers on samples immersed for >3 days in the SBF solution. Copyright © 2016 Elsevier B.V. All rights reserved.

Next Generation Thermal Barrier Coatings for the Gas Turbine Industry

Science.gov (United States)

Curry, Nicholas; Markocsan, Nicolaie; Li, Xin-Hai; Tricoire, Aurélien; Dorfman, Mitch

2011-01-01

The aim of this study is to develop the next generation of production ready air plasma sprayed thermal barrier coating with a low conductivity and long lifetime. A number of coating architectures were produced using commercially available plasma spray guns. Modifications were made to powder chemistry, including high purity powders, dysprosia stabilized zirconia powders, and powders containing porosity formers. Agglomerated & sintered and homogenized oven spheroidized powder morphologies were used to attain beneficial microstructures. Dual layer coatings were produced using the two powders. Laser flash technique was used to evaluate the thermal conductivity of the coating systems from room temperature to 1200 °C. Tests were performed on as-sprayed samples and samples were heat treated for 100 h at 1150 °C. Thermal conductivity results were correlated to the coating microstructure using image analysis of porosity and cracks. The results show the influence of beneficial porosity on reducing the thermal conductivity of the produced coatings.

Aminopeptidase N/CD13 as a Potential Therapeutic Target in Malignant Pleural Mesothelioma.

Science.gov (United States)

Otsuki, Takahiko; Nakashima, Taku; Hamada, Hironobu; Takayama, Yusuke; Akita, Shin; Masuda, Takeshi; Horimasu, Yasushi; Miyamoto, Shintaro; Iwamoto, Hiroshi; Fujitaka, Kazunori; Miyata, Yoshihiro; Miyake, Masayuki; Kohno, Nobuoki; Okada, Morihito; Hattori, Noboru

2018-03-08

Angiogenesis is a crucial factor in the progression of malignant pleural mesothelioma (MPM), and antiangiogenic strategies might be effective against MPM. Aminopeptidase N/CD13 (APN/CD13) promotes tumour angiogenesis and is associated with poor prognosis; however, its clinical significance in MPM remains unclear.In 37 consecutive patients with surgically resected MPM, we evaluated the association between immunohistochemical APN/CD13 expression in resected tumours and survival. Additionally, the antitumour and antiangiogenic effects of MT95-4, a fully humanized anti-APN/CD13 monoclonal antibody, were evaluated in mice orthotopically implanted with EHMES-10 (abundantly expressing APN/CD13) and MSTO-211H (scarcely expressing APN/CD13) MPM cells.High tumour APN/CD13 expression was associated with poor prognosis in MPM patients ( P =0.04), and MT95-4 treatment reduced tumour growth and angiogenesis in mice harbouring EHMES-10, but not MSTO-211H, cells. Furthermore, in mice harbouring EHMES-10 cells, MT95-4 combined with cisplatin more effectively suppressed tumour progression than cisplatin alone.Taken together these results suggested that APN/CD13 is implicated in the aggressiveness of MPM. Here, MT95-4 treatment reduced tumour progression likely by inhibiting angiogenesis, suggesting APN/CD13 as a potential molecular target for MPM treatment. Additionally, combination treatment with MT95-4 and cisplatin could represent a promising approach to treating MPM exhibiting high APN/CD13 expression. Copyright ©ERS 2018.

TEM Microstructure and Chemical Composition of Transition Zone Between Steel Tube and An Inconel 625 Weld Overlay Coating Produced by CMT Method

Directory of Open Access Journals (Sweden)

Rozmus-Górnikowska M.

2017-06-01

Full Text Available The aim of this work was to investigate the microstructure and chemical composition of the transition zone between 16Mo3 steel and Inconel 625 weld overlay coating produced by the Cold Metal Transfer (CMT method. Investigations were primarily carried out through transmission electron microscopy (TEM on thin foils prepared by FIB (Focus Ion Beam.

Hierarchical Micro-Nano Coatings by Painting

Science.gov (United States)

Kirveslahti, Anna; Korhonen, Tuulia; Suvanto, Mika; Pakkanen, Tapani A.

2016-03-01

In this paper, the wettability properties of coatings with hierarchical surface structures and low surface energy were studied. Hierarchically structured coatings were produced by using hydrophobic fumed silica nanoparticles and polytetrafluoroethylene (PTFE) microparticles as additives in polyester (PES) and polyvinyldifluoride (PVDF). These particles created hierarchical micro-nano structures on the paint surfaces and lowered or supported the already low surface energy of the paint. Two standard application techniques for paint application were employed and the presented coatings are suitable for mass production and use in large surface areas. By regulating the particle concentrations, it was possible to modify wettability properties gradually. Highly hydrophobic surfaces were achieved with the highest contact angle of 165∘. Dynamic contact angle measurements were carried out for a set of selected samples and low hysteresis was obtained. Produced coatings possessed long lasting durability in the air and in underwater conditions.

Anti-reflection coatings applied by acid leaching process

Science.gov (United States)

Pastirik, E.

1980-01-01

The Magicote C process developed by S.M. Thompsen was evaluated for use in applying an antireflective coating to the cover plates of solar panels. The process uses a fluosilicic acid solution supersaturated with silica at elevated temperature to selectively attack the surface of soda-lime glass cover plates and alter the physical and chemical composition of a thin layer of glass. The altered glass layer constitutes an antireflective coating. The process produces coatings of excellent optical quality which possess outstanding resistance to soiling and staining. The coatings produced are not resistant to mechanical abrasion and are attacked to some extent by glass cleansers. Control of the filming process was found to be difficult.

Transparent nanocrystalline diamond coatings and devices

Science.gov (United States)

Sumant, Anirudha V.; Khan, Adam

2017-08-22

A method for coating a substrate comprises producing a plasma ball using a microwave plasma source in the presence of a mixture of gases. The plasma ball has a diameter. The plasma ball is disposed at a first distance from the substrate and the substrate is maintained at a first temperature. The plasma ball is maintained at the first distance from the substrate, and a diamond coating is deposited on the substrate. The diamond coating has a thickness. Furthermore, the diamond coating has an optical transparency of greater than about 80%. The diamond coating can include nanocrystalline diamond. The microwave plasma source can have a frequency of about 915 MHz.

Cermet coatings for magnetic fusion reactors

International Nuclear Information System (INIS)

Smith, M.F.; Whitley, J.B.; McDonald, J.M.

1984-01-01

Cermet coatings consisting of SiC particles in an aluminum matrix were produced by a low pressure chamber plasma spray process. Properties of these coatings are being investigated to evaluate their suitability for use in the next generation of magnetic confinement fusion reactors. Although this preliminary study has focused primarily upon SiC-Al cermets, the deposition process can be adapted to other ceramic-metal combinations. Potential applications for cermet coatings in magnetic fusion devices are presented along with experimental results from thermal tests of candidate coatings. (Auth.)

Investigation of calcium phosphate coatings for biomedical applications

International Nuclear Information System (INIS)

Yusof Abdullah; Idris Besar; Muhammad Jamal Md Isa; Mohamad Abd Razak; Hyzan Mohd Yusof

1999-01-01

Calcium phosphate is the main constituent of our bone and tooth minerals. The use of this bioactive material for coating implant such as artificial joint prosthesis, therefore, can promote biological fixation and enhance biocompatibility. Our initial work has been focused on the evaluation of experimental conditions of coating preparation and the effects of post-deposition calcium phosphate coatings on stainless steel substrates. The coating layers were produced by the precipitation technique and coatings were carried out in sol-gel by the dipping method. For comparison purposes a wet method was used to obtain a fine calcium phosphate ceramic powder for fabrication of microcrystal suspension used as a coating material. Scanning electron microscopy (SEM), energy dispersive microanalysis (EDS), energy dispersive x-ray fluorescence (EDXRF) and x-ray diffraction (XRD) were used to characterise the morphology, chemical composition and structure of the coatings. The results showed that the dip coating of stainless steel substrates using viscous solutions lead to the formation of porous calcium phosphate layers. These results suggested that fabrication of bioactive calcium phosphate coatings using this route offers significant advantages over the currently used methods due to considerably lower temperature process involved and may produce better result for substrates with complex shapes

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

Data on the optimized sulphate electrolyte zinc rich coating produced through in-situ variation of process parameters.

Science.gov (United States)

Fayomi, Ojo Sunday Isaac

2018-02-01

In this study, a comprehensive effect of particle loading and optimised process parameter on the developed zinc electrolyte was presented. The depositions were performed between 10-30 min at a stirring rate of 200 rpm at room temperature of 30 °C. The effect of coating difference on the properties and interfacial surface was acquired, at a voltage interval between 0.6 and 1.0 V for the coating duration. The framework of bath condition as it influences the coating thickness was put into consideration. Hence, the electrodeposition data for coating thickness, and coating per unit area at constant distance between the anode and cathode with depth of immersion were acquired. The weight gained under varying coating parameter were acquired and could be used for designing and given typical direction to multifunctional performance of developed multifacetal coatings in surface engineering application.

Residual stress, mechanical and microstructure properties of multilayer Mo{sub 2}N/CrN coating produced by R.F Magnetron discharge

Energy Technology Data Exchange (ETDEWEB)

Bouaouina, B., E-mail: b.bouaouina@gmail.com [Department of physic, research unite UR-MPE, Boumerdes University 35000 (Algeria); Besnard, A. [Arts et Metiers ParisTech—LaBoMaP, 71250 Cluny (France); Abaidia, S.E. [Department of physic, research unite UR-MPE, Boumerdes University 35000 (Algeria); Haid, F. [CDTA, Plasma discharges Group, Baba hassen, Algers (Algeria)

2017-02-15

Highlights: • Depositing of crystallized molybdenum nitride and chromium nitride multilayer at room temperature. • Correlation between stress measurement and the shift of the XRD diffraction peak (1 1 1) of Mo{sub 2}N. • Studied the effect of the bi-layer thickness on the mechanical properties. - Abstract: We have investigated the effect of the period thickness of the multilayer Mo{sub 2}N/CrN deposited on Si substrate produced by reactive magnetron sputtering. Mo{sub 2}N presents a face centered cubic structure and CrN an orthorhombic one. The residual stress of the coatings was determined by the measurement of the substrate curvature. The microstructure of the multilayer was investigated from the X-ray diffraction and scanning electron microscopy (cross section images). The residual stresses resulting from the deposition of the different bi-layer thickness were measured and correlated to the structural properties of the coating as well as the nanoindentation analysis of the coating. The stresses are compressive and tensile for the individual Mo{sub 2}N and CrN layer respectively. The result shows that an increase of the multilayer coatings Mo{sub 2}N/CrN thicknesses induce an increase of the hardness and the elastic modulus, in the other hand the tensile stress increases. The shift of the XRD diffraction peak (1 1 1) of Mo{sub 2}N at high angle which means the reduction of the residual stress is in good agreement with the residual stresses measurements.

Protection of zirconium and its alloys by metallic coatings

International Nuclear Information System (INIS)

Loriers, H.; Lafon, A.; Darras, R.; Baque, P.

1968-01-01

At 600 deg. C in an atmosphere of carbon dioxide, zirconium and its alloys undergo corrosion which presents two aspects simultaneously: - formation of a surface layer of zirconia, - dissolution of oxygen in the alloy sub-layer leading to brittleness. The two phenomena greatly restrict the possibilities of using zirconium alloys as a canning material for fuel elements in CO 2 cooled nuclear reactors. An attempt has thus been made to limit, and perhaps to suppress, the corrosion effects in zirconium under these conditions by protecting it with metallic coatings. A first attempt to obtain a protection using copper-based coatings did not produce the result hoped for. Aluminium coatings produced by vacuum evaporation, followed by a consolidating thermal treatment make it possible to prevent the formation of the zirconia layer, but they do not eliminate the hardening effect produced by oxygen diffusion. On the other hand, electrolytically produced chromium deposits whose adherence is improved by a thermal vacuum treatment, counteract both these phenomena simultaneously. A similar result has been obtained with coatings of molybdenum produced by the technique of high-frequency inductive plasma sputtering. The particular effectiveness of the last two types of coatings is due to their structures characterized by the existence of an adherent film of chromium or molybdenum in the free state. (authors) [fr

Metal Matrix Composite Material by Direct Metal Deposition

Science.gov (United States)

Novichenko, D.; Marants, A.; Thivillon, L.; Bertrand, P. H.; Smurov, I.

Direct Metal Deposition (DMD) is a laser cladding process for producing a protective coating on the surface of a metallic part or manufacturing layer-by-layer parts in a single-step process. The objective of this work is to demonstrate the possibility to create carbide-reinforced metal matrix composite objects. Powders of steel 16NCD13 with different volume contents of titanium carbide are tested. On the base of statistical analysis, a laser cladding processing map is constructed. Relationships between the different content of titanium carbide in a powder mixture and the material microstructure are found. Mechanism of formation of various precipitated titanium carbides is investigated.

A Simple Method to Functionalize the Surface of Plasma Electrolytic Oxidation Produced TiO2 Coatings for Growing Hydroxyapatite

International Nuclear Information System (INIS)

Teng, Huan-Ping; Yang, Chia-Jung; Lin, Jia-Fu; Huang, Yu-Hsin; Lu, Fu-Hsing

2016-01-01

Highlights: • TiO 2 coatings with porous surfaces were produced by plasma electrolytic oxidation. • Simple pre-immersion in K 2 HPO 4 could functionalize the surfaces of the TiO 2 . • Such pre-immersion enhanced substantially the growth of hydroxyapatite in SBF. • Growth mechanisms of hydroxyapatite via the pre-immersion have been proposed. • MTT assay shows great osteoblast-like cell activity on the obtained hydroxyapatite. - Abstract: Conventionally, hydrothermal treatment was often used to modify the TiO 2 surface prior to the growth of hydroxyapatite (HA) that is one of the most important implant biomaterials. In this work, a simple pre-immersion of the obtained TiO 2 in a weak base, instead of the conventionally high pressure-temperature hydrothermal pre-treatment, was conducted prior to the growth of HA. Firstly, anatase TiO 2 coatings with porous surfaces were produced by plasma electrolytic oxidation with optimized processing parameters. X-ray diffraction patterns and field-emission microscopy reveal that the anatase TiO 2 films with porous surfaces were produced by plasma electrolytic oxidation. Subsequently, the films were pre-immersed in 0.1–2 M K 2 HPO 4 solutions for only 10 min. Fourier transform infrared spectroscopy shows that the −OH functional groups were generated after such pre-immersion, which could enhance significantly the growth of a single phase of HA in simulated body fluid (SBF). Growth mechanisms of HA via the pre-immersion treatment and soaking in SBF have been proposed. Moreover, the proliferation rate and attachment of the MG-63 osteoblast cells were greatly enhanced on the obtained HA compared to that without the immersion pre-treatment from the MTT assay and morphology analyses. This simple immersion pre-treatment evidently provides an easy route for the growth of HA and has great potential for biomedical applications.

Hard coatings

International Nuclear Information System (INIS)

Dan, J.P.; Boving, H.J.; Hintermann, H.E.

1993-01-01

Hard, wear resistant and low friction coatings are presently produced on a world-wide basis, by different processes such as electrochemical or electroless methods, spray technologies, thermochemical, CVD and PVD. Some of the most advanced processes, especially those dedicated to thin film depositions, basically belong to CVD or PVD technologies, and will be looked at in more detail. The hard coatings mainly consist of oxides, nitrides, carbides, borides or carbon. Over the years, many processes have been developed which are variations and/or combinations of the basic CVD and PVD methods. The main difference between these two families of deposition techniques is that the CVD is an elevated temperature process (≥ 700 C), while the PVD on the contrary, is rather a low temperature process (≤ 500 C); this of course influences the choice of substrates and properties of the coating/substrate systems. Fundamental aspects of the vapor phase deposition techniques and some of their influences on coating properties will be discussed, as well as the very important interactions between deposit and substrate: diffusions, internal stress, etc. Advantages and limitations of CVD and PVD respectively will briefly be reviewed and examples of applications of the layers will be given. Parallel to the development and permanent updating of surface modification technologies, an effort was made to create novel characterisation methods. A close look will be given to the coating adherence control by means of the scratch test, at the coating hardness measurement by means of nanoindentation, at the coating wear resistance by means of a pin-on-disc tribometer, and at the surface quality evaluation by Atomic Force Microscopy (AFM). Finally, main important trends will be highlighted. (orig.)

Analytical Modeling of Hard-Coating Cantilever Composite Plate considering the Material Nonlinearity of Hard Coating

Directory of Open Access Journals (Sweden)

Wei Sun

2015-01-01

Full Text Available Due to the material nonlinearity of hard coating, the coated structure produces the nonlinear dynamical behaviors of variable stiffness and damping, which make the modeling of hard-coating composite structure become a challenging task. In this study, the polynomial was adopted to characterize this material nonlinearity and an analytical modeling method was developed for the hard-coating composite plate. Firstly, to relate the hard-coating material parameters obtained by test and the analytical model, the expression of equivalent strain of composite plate was derived. Then, the analytical model of hard-coating composite plate was created by energy method considering the material nonlinearity of hard coating. Next, using the Newton-Raphson method to solve the vibration response and resonant frequencies of composite plate and a specific calculation procedure was also proposed. Finally, a cantilever plate coated with MgO + Al2O3 hard coating was chosen as study case; the vibration response and resonant frequencies of composite plate were calculated using the proposed method. The calculation results were compared with the experiment and general linear calculation, and the correctness of the created model was verified. The study shows the proposed method can still maintain an acceptable precision when the material nonlinearity of hard coating is stronger.

Electron beam treatments of electrophoretic ceramic coatings

International Nuclear Information System (INIS)

De Riccardis, M.F.; Carbone, D.; Piscopiello, E.; Antisari, M. Vittori

2008-01-01

In this work a method to densify ceramic coating obtained by electrophoresis and to improve its adhesion to the substrate is proposed. It consists in irradiating the coating surface by electron beam (EB). Alumina and alumina-zirconia coatings were deposited on stainless steel substrates and treated by low power EB. SEM, XRD and TEM characterizations demonstrated that the sintering occurred. Moreover, it is shown that on alumina-zirconia coating the EB irradiation produced a composite material consisting principally of tetragonal zirconia particles immersed in an amorphous alumina matrix. The adhesion stress of EB treated coating was estimated by stud pull test and it was found to be comparable to that of plasma-sprayed coatings

Colloidal spray method for low cost thin coating deposition

Science.gov (United States)

Pham, Ai-Quoc; Glass, Robert S.; Lee, Tae H.

2002-01-01

A dense or porous coating of material is deposited onto a substrate by forcing a colloidal suspension through an ultrasonic nebulizer and spraying a fine mist of particles in a carrier medium onto a sufficiently heated substrate. The spraying rate is essentially matched to the evaporation rate of the carrier liquid from the substrate to produce a coating that is uniformly distributed over the surface of the substrate. Following deposition to a sufficient coating thickness, a single sintering step may be used to produce a dense ceramic coating. Using this method, coatings ranging in thickness from about one to several hundred microns can be obtained. By using a plurality of compounds in the colloidal suspension, coatings of mixed composition can be obtained. By using a plurality of solutions and separate pumps and a single or multiple ultrasonic nebulizer(s), and varying the individual pumping rates and/or the concentrations of the solutions, a coating of mixed and discontinuously graded (e.g., stepped) or continuously graded layers may be obtained. This method is particularly useful for depositing ceramic coatings. Dense ceramic coating materials on porous substrates are useful in providing improved electrode performance in devices such as high power density solid oxide fuel cells. Dense ceramic coatings obtained by the invention are also useful for gas turbine blade coatings, sensors, steam electrolyzers, etc. The invention has general use in preparation of systems requiring durable and chemically resistant coatings, or coatings having other specific chemical or physical properties.

Investigation of tungsten coatings on graphite and CFC

International Nuclear Information System (INIS)

Neu, R; Maier, H; Gauthier, E; Greuner, H; Hirai, T; Hopf, Ch; Likonen, J; Maddaluno, G; Matthews, G F; Mitteau, R; Philipps, V; Piazza, G; Ruset, C

2007-01-01

In the frame of JET's ITER-like wall (ILW) project tungsten coatings on carbon fibre reinforced carbon substrates will be used in the divertor and highly loaded areas in the main chamber. Fourteen different types of samples were produced by physical or chemical vapour deposition and vacuum plasma spray (VPS) with coating thickness of 4, 10 and 200 μm. Similarly, three different VPS W coatings (200 μm) on two different graphite substrates, were produced for use at the strike-point regions of ASDEX Upgrade. All coatings were subjected to thermal screening and thermal cycling tests in the ion beam facility GLADIS. Additionally, the coatings intended for the ILW project were exposed to edge localized mode (ELM)-like thermal loads in the electron beam facility JUDITH. A general failure mode with the CFC substrate is crack formation upon cool-down, whereas the coatings on graphite do not show any crack formation. Additionally, metallographic investigations, x-ray diffraction measurements, adhesion testing as well as measurements on the contents of light impurities were performed

Controlled reactions between chromia and coating on alloy surface

DEFF Research Database (Denmark)

Linderoth, Søren

1996-01-01

An electrically conducting Sr-doped lanthanum chromite (LSC) coating has been produced by reacting a coating of fine particles of La oxide and Sr oxide with chromia formed as an external scale on a metallic alloy. In addition to the formation of LSC the coating also resulted in much reduced...... buckling of the underlying chromia layer compared with a non-coated alloy....

Ceramic Coatings for Clad (The C³ Project): Advanced Accident-Tolerant Ceramic Coatings for Zr-Alloy Cladding

Energy Technology Data Exchange (ETDEWEB)

Sickafus, Kurt E. [Univ. of Tennessee, Knoxville, TN (United States); Wirth, Brian [Univ. of Tennessee, Knoxville, TN (United States); Miller, Larry [Univ. of Tennessee, Knoxville, TN (United States); Weber, Bill [Univ. of Tennessee, Knoxville, TN (United States); Zhang, Yanwen [Univ. of Tennessee, Knoxville, TN (United States); Patel, Maulik [Univ. of Tennessee, Knoxville, TN (United States); Motta, Arthur [Pennsylvania State Univ., University Park, PA (United States); Wolfe, Doug [Pennsylvania State Univ., University Park, PA (United States); Fratoni, Max [Univ. of California, Berkeley, CA (United States); Raj, Rishi [Univ. of Colorado, Boulder, CO (United States); Plunkett, Kenneth [Univ. of Colorado, Boulder, CO (United States); Was, Gary [Univ. of Michigan, Ann Arbor, MI (United States); Hollis, Kendall [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Nelson, Andy [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Stanek, Chris [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Comstock, Robert [Westinghouse Electric Corporation, Pittsburgh, PA (United States); Partezana, Jonna [Westinghouse Electric Corporation, Pittsburgh, PA (United States); Whittle, Karl [Univ. of Sheffield (United Kingdom); Preuss, Michael [Univ. of Manchester (United Kingdom); Withers, Philip [Univ. of Manchester (United Kingdom); Wilkinson, Angus [Univ. of Oxford (United Kingdom); Donnelly, Stephen [Univ. of Huddersfield (United Kingdom); Riley, Daniel [Australian Nuclear Science and Technology Organisation, Syndney (Australia)

2017-02-14

The goal of this NEUP-IRP project is to develop a fuel concept based on an advanced ceramic coating for Zr-alloy cladding. The coated cladding must exhibit demonstrably improved performance compared to conventional Zr-alloy clad in the following respects: During normal service, the ceramic coating should decrease cladding oxidation and hydrogen pickup (the latter leads to hydriding and embrittlement). During a reactor transient (e.g., a loss of coolant accident), the ceramic coating must minimize or at least significantly delay oxidation of the Zr-alloy cladding, thus reducing the amount of hydrogen generated and the oxygen ingress into the cladding. The specific objectives of this project are as follows: To produce durable ceramic coatings on Zr-alloy clad using two possible routes: (i) MAX phase ceramic coatings or similar nitride or carbide coatings; and (ii) graded interface architecture (multilayer) ceramic coatings, using, for instance, an oxide such as yttria-stabilized zirconia (YSZ) as the outer protective layer. To characterize the structural and physical properties of the coated clad samples produced in 1. above, especially the corrosion properties under simulated normal and transient reactor operating conditions. To perform computational analyses to assess the effects of such coatings on fuel performance and reactor neutronics, and to perform fuel cycle analyses to assess the economic viability of modifying conventional Zr-alloy cladding with ceramic coatings. This project meets a number of the goals outlined in the NEUP-IRP call for proposals, including: Improve the fuel/cladding system through innovative designs (e.g. coatings/liners for zirconium-based cladding) Reduce or eliminate hydrogen generation Increase resistance to bulk steam oxidation Achievement of our goals and objectives, as defined above, will lead to safer light-water reactor (LWR) nuclear fuel assemblies, due to improved cladding properties and built-in accident resistance, as well as

Vacuum-plasma-sprayed silicon coatings

International Nuclear Information System (INIS)

Varacalle, D.J. Jr.; Herman, H.; Bancke, G.A.; Burchell, T.D.; Romanoski, G.R.

1991-01-01

Vacuum plasma spraying produces well-bonded dense stress-free coatings for a variety of materials on a wide range of substrates. The process is used in many industries for the excellent wear, corrosion resistance and high temperature behavior of the fabricated coatings. In this study, silicon metal was deposited on graphite to study the feasibility of preventing corrosion and oxidation of graphite components for nuclear reactors. Operating parameters were varied in a Taguchi design of experiments to display the range of the plasma processing conditions and their effect on the measured coating characteristics. The coating attributes evaluated were thickness, porosity, microhardness and phase content. This paper discusses the influence of the processing parameters on as-sprayed coating qualities. The paper also discusses the effect of thermal cycling on silicon samples in an inert helium atmosphere. The diffraction spectrum for a sample that experienced a 1600degC temperature cycle indicated that more than 99% of the coating transformed to β-SiC. The silicon coatings protected the graphite substrates from oxidation in one experiment. (orig.)

Corrosion protection of SiC-based ceramics with CVD mullite coatings

Energy Technology Data Exchange (ETDEWEB)

Auger, M.L.; Sarin, V.K. [Boston Univ., MA (United States). Dept. of Mfg. Engineering

1997-12-01

For the first time, crystalline mullite coatings have been chemically vapor deposited on SiC substrates to enhance its corrosion and oxidation resistance. Thermodynamic and kinetic considerations have been utilized to produce mullite coatings with a variety of growth rates, compositions, and morphologies. The flexibility of processing can be exploited to produce coated ceramics with properties tailored to specific applications and varied corrosive environments.

Synthesis and characterization of carbon coated nanoparticles produced by a continuous low-pressure plasma process

Energy Technology Data Exchange (ETDEWEB)

Panchal, Vineet; Neergat, Manoj [Indian Institute of Technology Bombay, Department of Energy Science and Engineering (India); Bhandarkar, Upendra, E-mail: bhandarkar@iitb.ac.in [Indian Institute of Technology Bombay, Department of Mechanical Engineering (India)

2011-09-15

Core-shell nanoparticles coated with carbon have been synthesized in a single chamber using a continuous and entirely low-pressure plasma-based process. Nanoparticles are formed in an argon plasma using iron pentacarbonyl Fe(CO){sub 5} as a precursor. These particles are trapped in a pure argon plasma by shutting off the precursor and then coated with carbon by passing acetylene along with argon as the main background gas. Characterization of the particles was carried out using TEM for morphology, XPS for elemental composition and PPMS for magnetic properties. Iron nanoparticles obtained were a mixture of FeO and Fe{sub 3}O{sub 4}. TEM analysis shows an average size of 7-14 nm for uncoated particles and 15-24 nm for coated particles. The effect of the carbon coating on magnetic properties of the nanoparticles is studied in detail.

Nanophase hardfaced coatings

Energy Technology Data Exchange (ETDEWEB)

Reisgen, U.; Stein, L.; Balashov, B.; Geffers, C. [RWTH Aachen University (Germany). ISF - Welding and Joining Institute

2009-08-15

This paper demonstrates the possibility of producing iron or chromium-based nanophase hardfaced coatings by means of common arc welding methods (TIG, PTA). The appropriate composition of the alloys to be deposited allows to control the structural properties and thus also the coating properties of the weld metal. Specific variations of the alloying elements allow also the realisation of a nanostructured solidification of the carbides and borides with cooling rates that are common for arc surfacing processes. The hardfaced coatings, which had been thus produced, showed phase dimensions of approximately 100-300 nm. Based on the results it is established that the influence of the surfacing parameters and of the coating thickness and thus the influence of the heat control on the nanostructuring process is, compared with the influence of the alloy composition, of secondary importance. The generation of nanoscale structures in hardfaced coatings allows the improvement of mechanical properties, wear resistance and corrosion resistance. Potential applications for these types of hardfaced coatings lie, in particular, in the field of cutting tools that are exposed to corrosion and wear. (Abstract Copyright [2009], Wiley Periodicals, Inc.) [German] Diese Arbeit demonstriert die Moeglichkeit zur Herstellung Eisen- und Chrom-basierter nanophasiger Hartauftragschweissschichten mithilfe ueblicher Lichtbogenschweissverfahren (WIG-, Plasma-Pulver-Auftragschweissen - PPA). Eine geeignete Zusammensetzung der aufzutragenden Legierungen ermoeglicht es, die Gefuegeeigenschaften und damit die Schichteigenschaften des Schweissgutes zu kontrollieren. Gezielte Variationen der Legierungselemente erlauben die Realisierung einer nanostrukturierten Erstarrung der Karbide und Boride bei fuer Lichtbogen-Auftragschweissprozessen ueblichen Abkuehlgeschwindigkeiten. In den so erzeugten Hartschichten werden Phasengroessen von ca. 100-300 nm erreicht. Auf Basis der gewonnenen Ergebnisse kann

Producing superhydrophobic roof tiles

International Nuclear Information System (INIS)

Carrascosa, Luis A M; Facio, Dario S; Mosquera, Maria J

2016-01-01

Superhydrophobic materials can find promising applications in the field of building. However, their application has been very limited because the synthesis routes involve tedious processes, preventing large-scale application. A second drawback is related to their short-term life under outdoor conditions. A simple and low-cost synthesis route for producing superhydrophobic surfaces on building materials is developed and their effectiveness and their durability on clay roof tiles are evaluated. Specifically, an organic–inorganic hybrid gel containing silica nanoparticles is produced. The nanoparticles create a densely packed coating on the roof tile surface in which air is trapped. This roughness produces a Cassie–Baxter regime, promoting superhydrophobicity. A surfactant, n-octylamine, was also added to the starting sol to catalyze the sol–gel process and to coarsen the pore structure of the gel network, preventing cracking. The application of ultrasound obviates the need to use volatile organic compounds in the synthesis, thereby making a ‘green’ product. It was also demonstrated that a co-condensation process effective between the organic and inorganic species is crucial to obtain durable and effective coatings. After an aging test, high hydrophobicity was maintained and water absorption was completely prevented for the roof tile samples under study. However, a transition from a Cassie–Baxter to a Wenzel state regime was observed as a consequence of the increase in the distance between the roughness pitches produced by the aging of the coating. (paper)

Corrosion Resistance of Ni/Al2O3 Nanocomposite Coatings

Directory of Open Access Journals (Sweden)

Beata KUCHARSKA

2016-05-01

Full Text Available Nickel matrix composite coatings with ceramic disperse phase have been widely investigated due to their enhanced properties, such as higher hardness and wear resistance in comparison to the pure nickel. The main aim of this research was to characterize the structure and corrosion properties of electrochemically produced Ni/Al2O3 nanocomposite coatings. The coatings were produced in a Watts bath modified by nickel grain growth inhibitor, cationic surfactant and the addition of alumina particles (low concentration 5 g/L. The process has been carried out with mechanical and ultrasonic agitation. The Ni/Al2O3 nanocomposite coatings were characterized by SEM, XRD and TEM techniques. In order to evaluate corrosion resistance of produced coatings, the corrosion studies have been carried out by the potentiodynamic method in a 0.5 M NaCl solution. The corrosion current, corrosion potential and corrosion rate were determined. Investigations of the morphology, topography and corrosion damages of the produced surface layers were performed by scanning microscope techniques. DOI: http://dx.doi.org/10.5755/j01.ms.22.1.7407

Annealed coated air-stable cobalt--rare earth alloy particles

International Nuclear Information System (INIS)

Smeggil, J.C.; Charles, R.J.

1975-01-01

A process is described for producing novel air-stable coated particles of a magnetic transition metal-rare earth alloy. An organometallic compound which decomposes at a temperature below 500 0 C is heated to produce a metal vapor which is contacted with particles of a transition metal-rare earth alloy to deposit a metal coating thereon. The coated particles are heated at a temperature ranging from 50 to 200 0 C for a period of time sufficient to increase their intrinsic coercive force by at least 10 percent. (U.S.)

Antibacterial effect of PEO coating with silver on AA7075

Energy Technology Data Exchange (ETDEWEB)

Cerchier, P., E-mail: pietrogiovanni.cerchier@studenti.unipd.it [Department of Industrial Engineering, University of Padua, Via Marzolo 9, 35131 Padova (Italy); Pezzato, L.; Brunelli, K. [Department of Industrial Engineering, University of Padua, Via Marzolo 9, 35131 Padova (Italy); Dolcet, P. [Department of Chemical Science, University of Padua, INSTM, UdR Padova and ICMATE-CNR, Padova (Italy); Bartolozzi, A.; Bertani, R.; Dabalà, M. [Department of Industrial Engineering, University of Padua, Via Marzolo 9, 35131 Padova (Italy)

2017-06-01

In this work, plasma electrolytic oxidation (PEO) coatings were produced on AA7075 using alkaline solution containing silicates compounds and silver micrometric particles in order to give to the coating an antimicrobial effect. In the optic of circular economy, silver chloride derived from the acid pre-treatment of electronic scraps was used as raw material and successively silver powders were synthesized from silver chloride solution using glucose syrup as reducing agent. The coatings were characterized by scanning electron microscope (SEM), X-ray diffraction analysis (XRD), X-ray photoelectron spectroscopy (XPS), potentiodynamic polarization test and antimicrobial tests. The results evidenced that the obtained coatings were homogenous and give to the samples higher corrosion resistance than untreated alloy. The silver particles, found both inside and outside of the pores that characterize the PEO layer, produced an efficacious antimicrobial effect both against E. coli and S. aureus. - Highlights: • Silver particles were incorporated into PEO coatings produced on aluminum alloys. • The incorporation was performed with direct addition of the particles in the electrolyte. • The particles resulted equally distributed on the samples surfaces. • The obtained coatings show antimicrobial activity with both E. coli and S. aureus. • The obtained coatings were characterized by acceptable corrosion resistance.

Antibacterial effect of PEO coating with silver on AA7075

International Nuclear Information System (INIS)

Cerchier, P.; Pezzato, L.; Brunelli, K.; Dolcet, P.; Bartolozzi, A.; Bertani, R.; Dabalà, M.

2017-01-01

In this work, plasma electrolytic oxidation (PEO) coatings were produced on AA7075 using alkaline solution containing silicates compounds and silver micrometric particles in order to give to the coating an antimicrobial effect. In the optic of circular economy, silver chloride derived from the acid pre-treatment of electronic scraps was used as raw material and successively silver powders were synthesized from silver chloride solution using glucose syrup as reducing agent. The coatings were characterized by scanning electron microscope (SEM), X-ray diffraction analysis (XRD), X-ray photoelectron spectroscopy (XPS), potentiodynamic polarization test and antimicrobial tests. The results evidenced that the obtained coatings were homogenous and give to the samples higher corrosion resistance than untreated alloy. The silver particles, found both inside and outside of the pores that characterize the PEO layer, produced an efficacious antimicrobial effect both against E. coli and S. aureus. - Highlights: • Silver particles were incorporated into PEO coatings produced on aluminum alloys. • The incorporation was performed with direct addition of the particles in the electrolyte. • The particles resulted equally distributed on the samples surfaces. • The obtained coatings show antimicrobial activity with both E. coli and S. aureus. • The obtained coatings were characterized by acceptable corrosion resistance.

"m=1" coatings for neutron guides

DEFF Research Database (Denmark)

Cooper-Jensen, C.P.; Vorobiev, A.; Klinkby, Esben Bryndt

2014-01-01

A substantial part of the price for a neutron guide is the shielding needed because of the gamma ray produced when neutrons are absorbed. This absorption occurs in the coating and the substrate of the neutron guides. Traditional m=1 coatings have been made of Ni and if reflectivity over...... the critical angle of Ni is needed one has used Ni58 or Ni/Ti multilayer coatings. Ni has one of the highest neutron scattering density but it also has a fairly high absorption cross section for cold and thermal neutrons and when a neutron is absorbed it emits a lot of gamma rays, some with energies above 9 Me...... of diamond coatings to show the potential for using these coatings in neutron guides....

On the interfacial degradation mechanisms of thermal barrier coating systems: Effects of bond coat composition

Energy Technology Data Exchange (ETDEWEB)

Wu, R.T., E-mail: WU.Rudder@nims.go.jp [International Center for Young Scientists, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba City, Ibaraki (Japan); Wang, X.; Atkinson, A. [Department of Materials, Imperial College London, Prince Consort Road, London SW7 2BP (United Kingdom)

2010-10-15

Thermal barrier coating (TBC) systems based on an electron beam physical vapour deposited, yttria-stabilized zirconia (YSZ) top coat and a substrate material of CMSX-4 superalloy were identically prepared to systematically study the behaviour of different bond coats. The three bond coat systems investigated included two {beta}-structured Pt-Al types and a {gamma}-{gamma}' type produced by Pt diffusion without aluminizing. Progressive evolution of stress in the thermally grown aluminium oxide (TGO) upon thermal cycling, and its relief by plastic deformation and fracture, were studied using luminescence spectroscopy. The TBCs with the LT Pt-Al bond coat failed by a rumpling mechanism that generated isolated cracks at the interface between the TGO and the YSZ. This reduced adhesion at this interface and the TBC delaminated when it could no longer resist the release of the stored elastic energy of the YSZ, which stiffened with time due to sintering. In contrast, the TBCs with Pt diffusion bond coats did not rumple, and the adhesion of interfaces in the coating did not obviously degrade. It is shown that the different failure mechanisms are strongly associated with differences in the high-temperature mechanical properties of the bond coats.

High temperature oxidation behavior of hafnium modified NiAl bond coat in EB-PVD thermal barrier coating system

Energy Technology Data Exchange (ETDEWEB)

Guo Hongbo; Sun Lidong; Li Hefei [Department of Material Science and Engineering, Beijing University of Aeronautics and Astronautics, No.37 Xueyuan Road, Beijing 100083 (China); Gong Shengkai [Department of Material Science and Engineering, Beijing University of Aeronautics and Astronautics, No.37 Xueyuan Road, Beijing 100083 (China)], E-mail: gongsk@buaa.edu.cn

2008-06-30

NiAl coatings doped with 0.5 at.% and 1.5 at.% Hf were produced by co-evaporation of NiAl and Hf ingots by electron beam physical vapor deposition (EB-PVD), respectively. The addition of 0.5 at.% Hf significantly improved the cyclic oxidation resistance of the NiAl coating. The TGO layer in the 1.5 at.% Hf doped NiAl coating is straight; while that in the 0.5 at.% Hf doped coating became undulated after thermal cycling. The doped NiAl thermal barrier coatings (TBCs) revealed improved thermal cycling lifetimes at 1423 K, compared to the undoped TBC. Failure of the 0.5 at.% Hf doped TBC occurred by cracking at the interface between YSZ topcoat and bond coat, while the 1.5 at.% Hf doped TBC cracked at the interface between bond coat and substrate.

Method for producing nanowire-polymer composite electrodes

Energy Technology Data Exchange (ETDEWEB)

Pei, Qibing; Yu, Zhibin

2017-11-21

A method for producing flexible, nanoparticle-polymer composite electrodes is described. Conductive nanoparticles, preferably metal nanowires or nanotubes, are deposited on a smooth surface of a platform to produce a porous conductive layer. A second application of conductive nanoparticles or a mixture of nanoparticles can also be deposited to form a porous conductive layer. The conductive layer is then coated with at least one coating of monomers that is polymerized to form a conductive layer-polymer composite film. Optionally, a protective coating can be applied to the top of the composite film. In one embodiment, the monomer coating includes light transducing particles to reduce the total internal reflection of light through the composite film or pigments that absorb light at one wavelength and re-emit light at a longer wavelength. The resulting composite film has an active side that is smooth with surface height variations of 100 nm or less.

Polymeric ionic liquid coatings versus commercial solid-phase microextraction coatings for the determination of volatile compounds in cheeses.

Science.gov (United States)

Trujillo-Rodríguez, María J; Yu, Honglian; Cole, William T S; Ho, Tien D; Pino, Verónica; Anderson, Jared L; Afonso, Ana M

2014-04-01

The extraction performance of four polymeric ionic liquid (PIL)-based solid-phase microextraction (SPME) coatings has been studied and compared to that of commercial SPME coatings for the extraction of 16 volatile compounds in cheeses. The analytes include 2 free fatty acids, 2 aldehydes, 2 ketones and 10 phenols and were determined by headspace (HS)-SPME coupled to gas chromatography (GC) with flame-ionization detection (FID). The PIL-based coatings produced by UV co-polymerization were more efficient than PIL-based coatings produced by thermal AIBN polymerization. Partition coefficients of analytes between the sample and the coating (Kfs) were estimated for all PIL-based coatings and the commercial SPME fiber showing the best performance among the commercial fibers tested: carboxen-polydimethylsyloxane (CAR-PDMS). For the PIL-based fibers, the highest K(fs) value (1.96 ± 0.03) was obtained for eugenol. The normalized calibration slope, which takes into account the SPME coating thickness, was also used as a simpler approximate tool to compare the nature of the coating within the determinations, with results entirely comparable to those obtained with estimated K(fs) values. The PIL-based materials obtained by UV co-polymerization containing the 1-vinyl-3-hexylimidazolium chloride IL monomer and 1,12-di(3-vinylimiazolium)dodecane dibromide IL crosslinker exhibited the best performance in the extraction of the select analytes from cheeses. Despite a coating thickness of only 7 µm, this copolymeric sorbent coating was capable of quantitating analytes in HS-SPME in a 30 to 2000 µg L(-1) concentration range, with correlation coefficient (R) values higher than 0.9938, inter-day precision values (as relative standard deviation in %) varying from 6.1 to 20%, and detection limits down to 1.6 µg L(-1). Copyright © 2013 Elsevier B.V. All rights reserved.

A community based study of NCD risk factors among adult population in Dehradun, India

Directory of Open Access Journals (Sweden)

Himanshu Agarwal

2016-06-01

Full Text Available Background: A Non-Communicable disease (NCD is one which is non-infectious and non-transmissible among people. NCDs account for leading causes of death and disease burden worldwide. To decrease the burden of NCDs experts stress on the importance of prevention and control with respect to modifiable risk factors. The World Health Organization's World Health Report 2002 identified tobacco use, alcohol consumption, overweight, physical inactivity, high blood pressure and high cholesterol as the most important risk factors for NCDs.(1  Aims & Objectives: 1. To know the prevalence of risk factors leading to NCDs in the study population. 2. To know the socio-demographic correlates associated with risk factors of NCDs. 3. To suggest appropriate recommendations regarding modifiable risk factors of NCDs in study population. Material & Methods: A Cross-sectional study, Community-based study among 18+ population in field practice areas of Community Medicine Department, SGRRIM&HS, Dehradun. Sample Size: 300 each in urban and rural, total 60. Results: The prevalence of Smoking was 11.3%, Smokeless tobacco use 10.5%, Alcohol use 13.2%, Unhealthy diet 99.5%, Low physical activity 0.8%, High BMI (≥ 25 kg/m2 51.2%, above normal waist-hip ratio 57.0%, Raised blood pressure 58.5% and raised blood sugar 25.2%. Conclusion: Smoking is significantly associated with age, sex and occupation. Raised blood pressure is significantly associated with age, sex and social class.

Coating of the orthopaedic titanium alloys with sol-gel derived hydroxyapatite

International Nuclear Information System (INIS)

Milev, A.; Green, D.; Chai, C.S.; Ben-Nissan, B.

1999-01-01

Hydroxyapatite (HAp) is known to be both biocompatible and bioactive material, however, due to its poor mechanical properties and design limitations is not suitable for applying as a load bearing implant. This could be overcome by using appropriate metallic substrates covered with HAp, derived via different techniques. These coatings allow improved adhesion strength of the load bearing substrate to the bone, resulting in shorter healing periods as well as predictable behaviour of the implant for longer periods of time. There are different techniques of producing HAp appropriate for coating purposes. Due to the small particle size of the grains derived, sol-gel route is preferable where lower sintering temperatures are of primary importance. For better adhesion between substrate and hydroxyapatite coating, the surface of titanium substrate, in this study, was converted to titanium nitride and/or oxynitride. Sintering temperatures of 900 deg C have been used for producing crystalline HAp coatings. The control of sol-gel solutions and the analysis of the coatings were carried out using XRD, SEM and DTA techniques. Results obtained indicate high quality HAp coatings can be produced on titanium substrates especially with complex shapes that benefits over the other coating methods

Interfacial reaction in cast WC particulate reinforced titanium metal matrix composites coating produced by laser processing

Science.gov (United States)

Liu, Dejian; Hu, Peipei; Min, Guoqing

2015-06-01

Laser injection of ceramic particle was conducted to produce particulate reinforced metal matrix composites (MMCs) coating on Ti-6Al-4V alloy. Cast WC particle (WCp) was used as injection reinforcement to avoid excessive release of carbon atoms into the melt pool. The interfaces and boundaries between WC and Ti matrix were investigated by electron microscopy study. Compared with single crystal WCp, cast WCp was an appropriate solution to control the reaction products (TiC) in the matrix and the total amount of reaction products was significantly reduced. Irregular-shape reaction layers were formed around cast WCp. The reaction layers consist of a W2C layer and a mixed layer of W and TiC. Such reaction layers are effective in load transfer under an external load.

Microstructures, hardness and bioactivity of hydroxyapatite coatings deposited by direct laser melting process

International Nuclear Information System (INIS)

Tlotleng, Monnamme; Akinlabi, Esther; Shukla, Mukul; Pityana, Sisa

2014-01-01

Hydroxyapatite (HAP) coatings on bioinert metals such as Ti–6Al–4V are necessary for biomedical applications. Together, HAP and Ti–6Al–4V are biocompatible and bioactive. The challenges of depositing HAP on Ti–6Al–4V with traditional thermal spraying techniques are well founded. In this paper, HAP was coated on Ti–6Al–4V using direct laser melting (DLM) process. This process, unlike the traditional coating processes, is able to achieve coatings with good metallurgical bonding and little dilution. The microstructural and mechanical properties, chemical composition and bio-activities of the produced coatings were studied with optical microscopy, scanning electron microscope equipped with energy dispersive X-ray spectroscopy, and Vickers hardness machine, and by immersion test in Hanks' solution. The results showed that the choice of the laser power has much influence on the evolving microstructure, the mechanical properties and the retainment of HAP on the surface of the coating. Also, the choice of laser power of 750 W led to no dilution. The microhardness results inferred a strong intermetallic–ceramic interfacial bonding; which meant that the 750 W coating could survive long in service. Also, the coating was softer at the surface and stronger in the heat affected zones. Hence, this process parameter setting can be considered as an optimal setting. The soak tests revealed that the surface of the coating had unmelted crystals of HAP. The CaP ratio conducted on the soaked coating was 2.00 which corresponded to tetra calcium phosphate. This coating seems attractive for metallic implant applications. - Highlights: • Characteristics of HAP coatings produced on Ti-6Al-4V achieved with direct laser melting are reported. • Optimal process parameters necessary to achieve biocompatible coating are reported. • The SEM micrograph of the soaked HAP coating revealed partially melted crystals of HAP. • The HAP coating was retained at the surface of

Microstructures, hardness and bioactivity of hydroxyapatite coatings deposited by direct laser melting process

Energy Technology Data Exchange (ETDEWEB)

Tlotleng, Monnamme, E-mail: MTlotleng@csir.co.za [Laser Materials Processing Group, National Laser Center CSIR, Pretoria 0001 (South Africa); Department of Mechanical Engineering Science, University of Johannesburg, Auckland Park, Kingsway Campus, Johannesburg 2006 (South Africa); Akinlabi, Esther [Department of Mechanical Engineering Science, University of Johannesburg, Auckland Park, Kingsway Campus, Johannesburg 2006 (South Africa); Shukla, Mukul [Department of Mechanical Engineering Technology, University of Johannesburg, Doornfontein Campus, Johannesburg 2006 (South Africa); Department of Mechanical Engineering, MNNIT, Allahabad, UP 211004 (India); Pityana, Sisa [Laser Materials Processing Group, National Laser Center CSIR, Pretoria 0001 (South Africa); Department of Chemical and Metallurgical Engineering, Tshwane University of Technology, Pretoria 0001 (South Africa)

2014-10-01

Hydroxyapatite (HAP) coatings on bioinert metals such as Ti–6Al–4V are necessary for biomedical applications. Together, HAP and Ti–6Al–4V are biocompatible and bioactive. The challenges of depositing HAP on Ti–6Al–4V with traditional thermal spraying techniques are well founded. In this paper, HAP was coated on Ti–6Al–4V using direct laser melting (DLM) process. This process, unlike the traditional coating processes, is able to achieve coatings with good metallurgical bonding and little dilution. The microstructural and mechanical properties, chemical composition and bio-activities of the produced coatings were studied with optical microscopy, scanning electron microscope equipped with energy dispersive X-ray spectroscopy, and Vickers hardness machine, and by immersion test in Hanks' solution. The results showed that the choice of the laser power has much influence on the evolving microstructure, the mechanical properties and the retainment of HAP on the surface of the coating. Also, the choice of laser power of 750 W led to no dilution. The microhardness results inferred a strong intermetallic–ceramic interfacial bonding; which meant that the 750 W coating could survive long in service. Also, the coating was softer at the surface and stronger in the heat affected zones. Hence, this process parameter setting can be considered as an optimal setting. The soak tests revealed that the surface of the coating had unmelted crystals of HAP. The CaP ratio conducted on the soaked coating was 2.00 which corresponded to tetra calcium phosphate. This coating seems attractive for metallic implant applications. - Highlights: • Characteristics of HAP coatings produced on Ti-6Al-4V achieved with direct laser melting are reported. • Optimal process parameters necessary to achieve biocompatible coating are reported. • The SEM micrograph of the soaked HAP coating revealed partially melted crystals of HAP. • The HAP coating was retained at the surface of

Stresses and Cracks in Surface Coatings

DEFF Research Database (Denmark)

Horsewell, Andy

2000-01-01

This extended abstract of the talk to be given at the Danish Metallurgical Society, Winter Meeting 1999, gives an outline of the areas of interest in current projects in wear and corrosion resistant coatings at Materials Technology, Technical University of Denmark (IPT, Materialeteknologi, DTU......). It also briefly describes our method of approach in analysing new coating / substrate combinations or new materials processing techniques for producing a given coating. We strive to combine, often in collaboration with others, a fundamental understanding of microstructure, mechanical properties...

Laser fabrication nanocrystalline coatings using simultaneous powders/wire feed

Science.gov (United States)

Li, Jianing; Zhai, Tongguang; Zhang, Yuanbin; Shan, Feihu; Liu, Peng; Ren, Guocheng

2016-07-01

Laser melting deposition (LMD) fabrication is used to investigate feasibilty of simultaneously feeding TC17 wire and the Stellite 20-Si3N4-TiC-Sb mixed powders in order to increase the utilization ratio of materials and also quality of LMD composite coatings on the TA1 substrate. SEM images indicated that such LMD coating with metallurgical joint to substrate was formed free of the obvious defects. Lots of the ultrafine nanocrystals (UNs) were produced, which distributed uniformly in some coating matrix location, retarding growth of the ceramics in a certain extent; UNs were intertwined with amorphous, leading the yarn-shape materials to be produced. Compared with substrate, an improvement of wear resistance was achieved for such LMD coating.

Physical and chemical characterization of Ag-doped Ti coatings produced by magnetron sputtering of modular targets

International Nuclear Information System (INIS)

Schmitz, Tobias; Warmuth, Franziska; Werner, Ewald; Hertl, Cornelia; Groll, Jürgen; Gbureck, Uwe; Moseke, Claus

2014-01-01

Silver-doped Ti films were produced using a single magnetron sputtering source equipped with a titanium target containing implemented silver modules under variation of bias voltage and substrate temperature. The Ti(Ag) films were characterized regarding their morphology, contact angle, phase composition, silver content and distribution as well as the elution of Ag + ions into cell media. SEM and AFM pictures showed that substrate heating during film deposition supported the formation of even and dense surface layers with small roughness values, an effect that could even be enforced, when a substrate bias voltage was applied instead. The deposition of both Ti and Ag was confirmed by X-ray diffraction. ICP-MS and EDX showed a clear correlation between the applied sputtering parameters and the silver content of the coatings. Surface-sensitive XPS measurements revealed that higher substrate temperatures led to an accumulation of Ag in the near-surface region, while the application of a bias voltage had the opposite effect. Additional elution measurements using ICP-MS showed that the release kinetics depended on the amount of silver located at the film surface and hence could be tailored by variation of the sputter parameters. - Highlights: • Modular targets were used to deposit Ti(Ag) films. • Ag-content is adjustable by bias voltage, sputtering power and substrate temperature. • Coating parameters significantly change film morphology and roughness. • A critical parameter for Ag release is the fraction of silver on the film surface

Nanocomposite Coatings: Preparation, Characterization, Properties, and Applications

Directory of Open Access Journals (Sweden)

Phuong Nguyen-Tri

2018-01-01

Full Text Available Incorporation of nanofillers into the organic coatings might enhance their barrier performance, by decreasing the porosity and zigzagging the diffusion path for deleterious species. Thus, the coatings containing nanofillers are expected to have significant barrier properties for corrosion protection and reduce the trend for the coating to blister or delaminate. On the other hand, high hardness could be obtained for metallic coatings by producing the hard nanocrystalline phases within a metallic matrix. This article presents a review on recent development of nanocomposite coatings, providing an overview of nanocomposite coatings in various aspects dealing with the classification, preparative method, the nanocomposite coating properties, and characterization methods. It covers potential applications in areas such as the anticorrosion, antiwear, superhydrophobic area, self-cleaning, antifouling/antibacterial area, and electronics. Finally, conclusion and future trends will be also reported.

Oxidation-resistant interface coatings for SiC/SiC composites

Energy Technology Data Exchange (ETDEWEB)

Stinton, D.P.; Kupp, E.R.; Hurley, J.W.; Lowden, R.A. [Oak Ridge National Lab., TN (United States)] [and others

1996-08-01

The characteristics of the fiber-matrix interfaces in ceramic matrix composites control the mechanical behavior of these composites. Finite element modeling (FEM) was performed to examine the effect of interface coating modulus and coefficient of thermal expansion on composite behavior. Oxide interface coatings (mullite and alumina-titania) produced by a sol-gel method were chosen for study as a result of the FEM results. Amorphous silicon carbide deposited by chemical vapor deposition (CVD) is also being investigated for interface coatings in SiC-matrix composites. Processing routes for depositing coatings of these materials were developed. Composites with these interfaces were produced and tested in flexure both as-processed and after oxidation to examine the suitability of these materials as interface coatings for SiC/SiC composites in fossil energy applications.

Processing and properties of electrodeposited layered surface coatings

DEFF Research Database (Denmark)

Horsewell, Andy

1998-01-01

Hard chromium, produced by conventional dir ect curl ent (DC) electrodeposition, cannot be deposited to thicknesses gl enter than about 5 mu m because of the buildup of processing stresses which cause channel cracks in the coating. Much thicker chromium coatings map be produced by depositing a la...... geometry is almost always analogous to bending, and fracture resistance is provided through deviation of the channel crack by weak interfaces, resulting in 'terrace cracking'....

Physical properties of pyrolytically sprayed tin-doped indium oxide coatings

NARCIS (Netherlands)

Haitjema, H.; Elich, J.J.P.

1991-01-01

The optical and electrical properties of tin-doped indium oxide coatings obviously depend on a number of production parameters. This dependence has been studied to obtain a more general insight into the relationships between the various coating properties. The coatings have been produced by spray

Coated fuel particles: requirements and status of fabrication technology

International Nuclear Information System (INIS)

Huschka, H.; Vygen, P.

1977-01-01

Fuel cycle, design, and irradiation performance requirements impose restraints on the fabrication processes. Both kernel and coating fabrication processes are flexible enough to adapt to the needs of the various existing and proposed high-temperature gas-cooled reactors. Extensive experience has demonstrated that fuel kernels with excellent sphericity and uniformity can be produced by wet chemical processes. Similarly experience has shown that the various multilayer coatings can be produced to fully meet design and specification requirements. Quality reliability of coated fuel particles is ensured by quality control and quality assurance programs operated by an aduiting system that includes licensing officials and the customer

Nanocomposited coatings produced by laser-assisted process to prevent silicone hydogels from protein fouling and bacterial contamination

International Nuclear Information System (INIS)

Huang, Guobang; Chen, Yi; Zhang, Jin

2016-01-01

Graphical abstract: Nanocomposited-coating was deposited on silicone hydrogel by using the matrix-assisted pulsed laser evaporation (MAPLE) process. The ZnO–PEG nanocomposited coating reduces over 50% protein absorption on silicone hydrogel, and can inhibit the bacterial growth efficiently. - Highlights: • We developed a nanocomposited coating to prevent silicone hydrogel from biofouling. • Matrix-assisted pulsed laser evaporation can deposit inorganic–organic nanomaterials. • The designed nanocomposited coating reduces protein absorption by over 50%. • The designed nanocomposited coating shows significant antimicrobial efficiency. - Abstract: Zinc oxide (ZnO) nanoparticles incorporating with polyethylene glycol (PEG) were deposited together on the surface of silicone hydrogel through matrix-assisted pulsed laser evaporation (MAPLE). In this process, frozen nanocomposites (ZnO–PEG) in isopropanol were irradiated under a pulsed Nd:YAG laser at 532 nm for 1 h. Our results indicate that the MAPLE process is able to maintain the chemical backbone of polymer and prevent the nanocomposite coating from contamination. The ZnO–PEG nanocomposited coating reduces over 50% protein absorption on silicone hydrogel. The cytotoxicity study shows that the ZnO–PEG nanocomposites deposited on silicone hydrogels do not impose the toxic effect on mouse NIH/3T3 cells. In addition, MAPLE-deposited ZnO–PEG nanocomposites can inhibit the bacterial growth significantly.

Decreased Bacterial Attachment and Protein Adsorption to Coatings Produced by Low Enegy Plasma Polymerization

DEFF Research Database (Denmark)

Andersen, T.E.; Kingshott, Peter; Benter, M.

.figure) .and E. coli grown on uncoated silicone compared to PP-PVP coated silicone (right figure). Results from the flow chamber analysis shows PP-PVP to be very good at preventing E. coli colonization during prolonged growth in flow chamber. At this point other surfaces and bacteria remains to be tested...... adsorption and bacteria attachment/colonization. This is emphasized by the fact that long dwelling urinary catheters, which is a typical silicone medical device, causes 5% per day incidence of urinary tract infection [1,2]. A demand therefore exists for surface modifications providing the silicone material......-coated crystals were then treated with one of the plasma polymerized coatings. Adsorption of fibrinogen, human serum albumin or immunoglobulin G was measured using a QCM-D instrument [5] (model E4, Q-Sense AB, Vastra Frolunda, Sweden) using a solution of 50llg/1 protein in PBS buffer. Results and Discussion: Our...

Evaluation of Plasma Spray hydroxy Apatite Coatings on Metallic Materials

International Nuclear Information System (INIS)

Take, S.; Mitsul, K.; Kasahara, M.; Sawal, R.; Izawa, S.; Nakayama, M.; Itoi, Y.

2007-01-01

Biocompatible Hydroxy apatite (HAp) coatings on metallic substrate by plasma spray techniques have been developed. Long-term credibility of plasma spray HAp coatings has been evaluated in physiological saline by electrochemical measurements. It was found that the corrosion resistance of SUS316L based HAp/Ti combined coatings was excellent even after more than 10 weeks long-term immersion. It was shown that postal heat treatment improved both the crystallinity and corrosion resistance of HAp. By lowering cooling rate during heat treatment process, less cracks produced in HAp coating layer, which lead to higher credibility of HAp during immersion in physiological saline. The ICP results showed that the dissolution level of substrate metallic ions was low and HAp coatings produced in this research can be acceptable as biocompatible materials. Also, the concentration of dissolved ions from HAp coatings with postal heat treatment was lower compared to those from samples without postal heat treatment. The adherence of HAp coatings with Ti substrate and other mechanical properties were also assessed by three-point bending test. The poor adhesion of HAp coating to titanium substrate can be improved by introducing a plasma spray titanium intermediate layer

A new titanium based alloy Ti–27Nb–13Zr produced by powder metallurgy with biomimetic coating for use as a biomaterial

Energy Technology Data Exchange (ETDEWEB)

Mendes, Marcio W.D., E-mail: mwdmendes@ipen.com; Ágreda, Carola G.; Bressiani, Ana H.A.; Bressiani, José C.

2016-06-01

Titanium alloys are widely used in biomedical applications due to their excellent properties such as high strength, good corrosion resistance and biocompatibility. Titanium alloys with alloying elements such as Nb and Zr are biocompatible and have Young's modulus close to that of human bone. To increase the bioactivity of titanium alloy surfaces is used chemical treatment with NaOH followed by immersion in simulated body fluid (SBF). The purpose of this study was to produce the alloy Ti–27Nb–13Zr with low Young's modulus by powder metallurgy using powders produced by the HDH process. The formation of biomimetic coatings on samples immersed in SBF for 3, 7, 11 and 15 days was evaluated. Characterization of the coating was performed by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and scanning electron microscope. The microstructure and composition of the alloy were determined using SEM and XRD, while the mechanical properties were evaluated by determining the elastic modulus and the Vickers microhardness. The sintered alloys were composed of α and β phases, equiaxed grains and with density around 97.8% of its theoretical density. The Vickers microhardness and elasticity modulus of the alloy were determined and their values indicate that this alloy can be used as a biomaterial. Analysis of the coating revealed the presence of calcium phosphate layers on samples immersed for > 3 days in the SBF solution. - Highlights: • The alloy is classified as α + β and the milling time influences the formation of these phases. • Dissolution of Nb is related to the mechanical properties of the alloy. • It's possible to form apatite on all samples immersed in SBF from 3 days. • The alloy can be used in orthopedic applications or in dental applications.

Process for producing uranium carbide spheroids

International Nuclear Information System (INIS)

Shennan, J.V.; Ford, L.H.

1976-01-01

The invention deals with a method to produce UC spheroids which are filled into molded bodies of fire-proof material for fuel elements. The UC fuel particles are doubly coated: a first thin layer of pyrolytic carbon is coated at low temperature (1,200-1,400 0 C), a second layer of fire-proof material (e.g. SiC) is coated at a higher temperature (above 1,500 0 C) which holds back the fission products. The process is explained in more detail using an example. (GSCH) [de

Hybrid calcium phosphate coatings for implants

Science.gov (United States)

Malchikhina, Alena I.; Shesterikov, Evgeny V.; Bolbasov, Evgeny N.; Ignatov, Viktor P.; Tverdokhlebov, Sergei I.

2016-08-01

Monophasic biomaterials cannot provide all the necessary functions of bones or other calcined tissues. It is necessary to create for cancer patients the multiphase materials with the structure and composition simulating the natural bone. Such materials are classified as hybrid, obtained by a combination of chemically different components. The paper presents the physical, chemical and biological studies of coatings produced by hybrid technologies (HT), which combine primer layer and calcium phosphate (CaP) coating. The first HT type combines the method of vacuum arc titanium primer layer deposition on a stainless steel substrate with the following micro-arc oxidation (MAO) in phosphoric acid solution with addition of calcium compounds to achieve high supersaturated state. MAO CaP coatings feature high porosity (2-8%, pore size 5-7 µm) and surface morphology with the thickness greater than 5 µm. The thickness of Ti primer layer is 5-40 µm. Amorphous MAO CaP coating micro-hardness was measured at maximum normal load Fmax = 300 mN. It was 3.1 ± 0.8 GPa, surface layer elasticity modulus E = 110 ± 20 GPa, roughness Ra = 0.9 ± 0.1 µm, Rz = 7.5 ± 0.2 µm, which is less than the titanium primer layer roughness. Hybrid MAO CaP coating is biocompatible, able to form calcium phosphates from supersaturated body fluid (SBF) solution and also stimulates osteoinduction processes. The second HT type includes the oxide layer formation by thermal oxidation and then CaP target radio frequency magnetron sputtering (RFMS). Oxide-RFMS CaP coating is a thin dense coating with good adhesion to the substrate material, which can be used for metal implants. The RFMS CaP coating has thickness 1.6 ± 0.1 µm and consists of main target elements calcium and phosphorus and Ca/P ratio 2.4. The second HT type can form calcium phosphates from SBF solution. In vivo study shows that hybrid RFMS CaP coating is biocompatible and produces fibrointegration processes.

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

International Nuclear Information System (INIS)

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

2007-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2007-10-15

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

Electrochemical characterization of V{sub x}Nb{sub y}C{sub z}/Bi{sub x}Ti{sub y}O{sub z} coatings produced through thermo-reactive diffusion and the sputtering technique

Energy Technology Data Exchange (ETDEWEB)

Castro H, S. A.; Alfonso, J. E.; Olaya, J. J., E-mail: jealfonso@unal.edu.co [Universidad Nacional de Colombia, Departamento de Fisica, Grupo de Ciencia de Materiales y Superficies, AA-14490 Bogota (Colombia)

2016-11-01

We present and experimental study of the structural evolution of a bilayer V{sub x}Nb{sub y}C{sub z}/Bi{sub x}Ti{sub y}O{sub z} coating produced via thermo-reactive diffusion (TRD) and the RF sputtering process on D-2 steel substrate. The TRD treatments were carried out in a molten mixture consisting of borax, ferro-niobium, ferro-vanadium, and aluminum, at 1313 K for 3 hours, using a resistance-heating furnace. Bi{sub x}Ti{sub y}O{sub z} coatings were deposited using RF magnetron sputtering on TRD coatings, in order to carry out a study of the corrosion behavior of this compound. The crystallographic structure of the coatings was determined via X-ray diffraction, the corrosion resistance was analyzed through the potentiodynamic polarization test (Tafel Extrapolation) and electrochemical impedance spectroscopic analysis (EIS). X-ray diffraction patterns showed that the ternary coating (VNbC{sub 2}) was preferentially oriented along the [200] direction with a cubic-centered face structure, and the Bi{sub x}Ti{sub y}O{sub z} coatings were amorphous. The electrochemical studies showed that the resistance corrosion of the coatings increased with respect to the bare substrate, and that polarization resistance in the bilayer coatings increased with respect to the ternary coatings, suggesting that the titanate has anti corrosive barrier effects. (Author)

Alternative waste form development - low-temperature pyrolytic carbon coatings

International Nuclear Information System (INIS)

Oma, K.H.; Rusin, J.M.; Kidd, R.W.; Browning, M.F.

1981-01-01

Although several chemical vapor deposition (CVD) - coated waste forms have been successfully produced, some major disadvantages associated with the high-temperature fluidized-bed CVD coating process exist. To overcome these disadvantages, the Pacific Northwest Laboratory has initiated the development of a pyrolytic carbon CVD coating system to coat large waste-form particles at temperatures ranging from 400 to 500/degree/C. This relatively simple system has been used to coat kilogram quantities of simulated waste-glass marbles. Further development of this system could result in a viable process to coat bulk quantities of both glass and ceramic waste forms. This paper discusses various aspects of the development work, including coating techniques, parametric study, and coater equipment. 10 refs

Structure and corrosion properties of PVD Cr-N coatings

CERN Document Server

Liu, C; Ziegele, H; Leyland, A; Matthews, A

2002-01-01

PVD Cr-N coatings produced by physical vapor deposition (PVD) are increasingly used for mechanical and tribological applications in various industrial sectors. These coatings are particularly attractive for their excellent corrosion resistance, which further enhances the lifetime and service quality of coated components. PVD Cr-N coated steels in an aqueous solution are usually corroded by galvanic attack via through-coating 'permeable' defects (e.g., pores). Therefore, the corrosion performance of Cr-N coated steel is determined by a number of variables of the coating properties and corrosive environment. These variables include: (i) surface continuity and uniformity; (ii) through-coating porosity; (iii) film density and chemical stability; (iv) growth stresses; (v) interfacial and intermediate layers; (vi) coating thickness; (vii) coating composition; and (viii) substrate properties. In this article, PVD Cr-N coatings were prepared, by electron-beam PVD and sputter deposition, with different compositions, t...

Corrosion-resistant coating development

Energy Technology Data Exchange (ETDEWEB)

Stinton, D.P.; Kupp, D.M.; Martin, R.L. [Oak Ridge National Lab., TN (United States)

1997-12-01

SiC-based heat exchangers have been identified as the prime candidate material for use as heat exchangers in advanced combined cycle power plants. Unfortunately, hot corrosion of the SiC-based materials created by alkali metal salts present in the combustion gases dictates the need for corrosion-resistant coatings. The well-documented corrosion resistance of CS-50 combined with its low (and tailorable) coefficient of thermal expansion and low modulus makes CS-50 an ideal candidate for this application. Coatings produced by gelcasting and traditional particulate processing have been evaluated.

Wrinkling of solidifying polymeric coatings

Science.gov (United States)

Basu, Soumendra Kumar

2005-07-01

In coatings, wrinkles are viewed as defects or as desired features for low gloss, and texture. In either case, discovering the origin of wrinkles and the conditions that lead to their formation is important. This research examines what wrinkling requires and proposes a mechanism to explain the observations. All curing wrinkling coatings contain multi-functional reactants. Upon curing, all develop a depth-wise gradient in solidification that result in a cross-linked elastic skin atop a viscous bottom layer. It is hypothesized that compressive stress develops in the skin when liquid below diffuses up into the skin. High enough compressive stress buckles the skin to produce wrinkles. The hypothesis is substantiated by experimental and theoretical evidences. Effects of various application and compositional parameters on wrinkle size in a liquid-applied acrylic coating and a powder-applied epoxy coating were examined. All three components, namely resin, cross-linker and catalyst blocked with at least equimolar volatile blocker, proved to be required for wrinkling. The wrinkling phenomenon was modeled with a theory that accounts for gradient generation, cross-linking reaction and skinning; predictions compared well with observations. Two-layer non-curing coatings that have a stiff elastic layer atop a complaint elastic bottom layer wrinkled when the top layer is compressed. The top layer was compressed by either moisture absorption or differential thermal expansion. Experimental observations compared well with predictions from a theory based on force balance in multilayer systems subjected to differential contraction or expansion. A model based on the Flory-Rehner free energy of a constrained cross-linked gel was constructed that predicts the compressive stress generated in a coating when it absorbs solvent. Linear stability analysis predicts that when a compressed elastic layer is attached atop a viscous layer, it is always unstable to buckles whose wavelength exceeds a

Coated air-stable cobalt--rare earth alloy particles and method

International Nuclear Information System (INIS)

Smeggil, J.C.; Charles, R.J.

1975-01-01

A process is described for producing novel air-stable coated particles of a magnetic transition metal-rare earth alloys. An organometallic compound which decomposes at a temperature below 500 0 C is heated to produce a metal vapor which is contacted with particles of a transition metal-rare earth alloy to deposit a metal coating on the particles. (U.S.)

Identification of horse chestnut coat color genotype using SNaPshot?

OpenAIRE

Rendo, Fernando; Iriondo, Mikel; Manzano, Carmen; Estonba, Andone

2009-01-01

Abstract Background The Cantabrian Coast horse breeds of the Iberian Peninsula have mainly black or bay colored coats, but alleles responsible for a chestnut coat color run in these breeds and occasionally, chestnut horses are born. Chestnut coat color is caused by two recessive alleles, e and ea, of the melanocortin-1 receptor gene, whereas the presence of the dominant, wild-type E allele produces black or bay coat horses. Because black or bay colored coats are considered as the purebred phe...

Zirconium nitride hard coatings

International Nuclear Information System (INIS)

Roman, Daiane; Amorim, Cintia Lugnani Gomes de; Soares, Gabriel Vieira; Figueroa, Carlos Alejandro; Baumvol, Israel Jacob Rabin; Basso, Rodrigo Leonardo de Oliveira

2010-01-01

Zirconium nitride (ZrN) nanometric films were deposited onto different substrates, in order to study the surface crystalline microstructure and also to investigate the electrochemical behavior to obtain a better composition that minimizes corrosion reactions. The coatings were produced by physical vapor deposition (PVD). The influence of the nitrogen partial pressure, deposition time and temperature over the surface properties was studied. Rutherford backscattering spectrometry (RBS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscopy (SEM) and corrosion experiments were performed to characterize the ZrN hard coatings. The ZrN films properties and microstructure changes according to the deposition parameters. The corrosion resistance increases with temperature used in the films deposition. Corrosion tests show that ZrN coating deposited by PVD onto titanium substrate can improve the corrosion resistance. (author)

The adherence of aluminide coatings on MANET II stainless steel and their effect on its mechanical properties

International Nuclear Information System (INIS)

Sample, T.; Fenici, P.; Kolbe, H.; Orecchia, L.

1994-01-01

This paper describes the production and testing of two different aluminide coatings on the surface of MANET II stainless steel. The coatings were produced by heat treatment of a pure aluminium layer (∼ 100 μm) which had been deposited by vacuum plasma spray. Series 1 coatings were produced by a single heat treatment (1023 K/2h) while series 2 coatings were produced by two consecutive heat treatments (1348 K/30 min, 1023 K/2h). Series 1 coatings were ∼ 120 μm thick, richer in aluminium and harder than series 2 coatings which formed two layers of ∼ 120 μm each. Due to their softer character, series 2 coatings exhibited a greater resistance to cracking under cyclic testing than series 1 coatings. Tensile tests of coated specimens indicated that the coating procedures did not degrade the mechanical properties of the bulk MANET II. (author) 8 refs.; 3 figs.; 3 tabs

Porous SiO2/HAp Coatings on Cp-Titanium Grade 1 Surfaces Produced by Electrophoretic Deposition

Directory of Open Access Journals (Sweden)

Moskalewicz T.

2016-12-01

Full Text Available Porous hydroxyapatite doped SiO2 coatings were electrophoretically deposited (EPD on commercially pure titanium. The influence of EPD parameters on coatings quality was investigated. Microstructural observation was done using transmission and scanning electron microscopy as well as X-ray diffractometry.

Influence of Nitrided Layer on The Properties of Carbon Coatings Produced on X105CrMo17 Steel Under DC Glow-Discharge Conditions

Directory of Open Access Journals (Sweden)

Tomasz BOROWSKI

2016-09-01

Full Text Available In most cases, machine components, which come in contact with each other, are made of steel. Common steel types include 100Cr6 and X105CrMo17 are widely used in rolling bearings, which are subjected to high static loads. However, more and more sophisticated structural applications require increasingly better performance from steel. The most popular methods for improving the properties of steel is carburisation or nitriding. Unfortunately, when very high surface properties of steel are required, this treatment may be insufficient. Improvement of tribological properties can be achieved by increasing the hardness of the surface, reducing roughness or reducing the coefficient of friction. The formation of composite layers on steel, consisting of a hard nitride diffusion layer and an external carbon coating with a low coefficient of friction, seems to be a prospect with significant potential. The article describes composite layers produced on X105CrMo17 steel and defines their morphology, surface roughness and their functional properties such as: resistance to friction-induced wear, coefficient of friction and corrosion resistance. The layers have been formed at a temperature of 370°C in successive processes of: nitriding in low-temperature plasma followed by deposition of a carbon coating under DC glow-discharge conditions. An evaluation was also made of the impact of the nitrided layers on the properties and morphology of the carbon coatings formed by comparing them to coatings formed on non-nitrided X105CrMo17 steel substrates. A study of the surface topography, adhesion, resistance to friction-induced wear and corrosion shows the significant importance of the substrate type the carbon coatings are formed on.DOI: http://dx.doi.org/10.5755/j01.ms.22.3.7532

Method and compositions for producting optically clear photocatalytic coatings

DEFF Research Database (Denmark)

2009-01-01

The invention relates to a method and compositions for producing a hydrophilic coating on a surface of a solid material. The method comprises a cleaning step and a coating step. The cleaning step may be preceded by an initial cleaning step and it may optionally be succeeded by a preconditioning...... step prior to the coating step. The cleaning step comprises cleaning and preconditioning a surface of a material by use of a first cleaning fluid composition comprising ceria (CeO2) particles. The coating step comprises treatment by use of a coating fluid composition comprising photocatalytically...

Strippable coating used for the TMI-2 reactor building decontamination

International Nuclear Information System (INIS)

Adams, J.W.; Dougherty, D.R.; Barletta, R.E.

1984-01-01

Strippable coating material used in the TMI-2 reactor building decontamination has been tested for Sr, Cs, and Co leachability, for radiation stability, thermal stability, and for resistance to biodegradation. It was also immersion tested in water, a water solution saturated with toluene and xylene, toluene, xylene, and liquid scintillation counting (LSC) cocktail. Leach testing resulted in all of the Cs and Co activity and most of the Sr activity being released from the coating in just a few days. Immersion resulted in swelling of the coating in all of the liquids tested. Gamma irradiation and heating of the coating did not produce any apparent physical changes in the coating to 1 x 10 8 rad and 100 0 C; however, gas generation of H 2 , CO, CO 2 was observed in both cases. Biodegradation of the coating occurred readily in soils as indicated by monitoring CO 2 produced from microbial respiration. These test results indicate that strippable coating radwaste would have to be stabilized to meet the requirements for Class B waste outlined in 10 CFR Part 61 and the NRC Draft Technical Position on Waste Form

Gold nanoparticles: BSA (Bovine Serum Albumin) coating and X-ray irradiation produce variable-spectrum photoluminescence

Energy Technology Data Exchange (ETDEWEB)

Lee, Kuo-Hao [Department of Electrophysics, National Chiao Tung University, Hsinchu, Taiwan (China); Institute of Physics, Academia Sinica, Taipei 115, Taiwan (China); Lai, Sheng-Feng [Institute of Physics, Academia Sinica, Taipei 115, Taiwan (China); Department of Engineering Science, National Cheng Kung University, Tainan 701, Taiwan (China); Lin, Yan-Cheng; Chou, Wu-Ching [Department of Electrophysics, National Chiao Tung University, Hsinchu, Taiwan (China); Ong, Edwin B.L. [Institute of Physics, Academia Sinica, Taipei 115, Taiwan (China); Tan, Hui-Ru [Institute of Materials Research and Engineering, 3 Research Link, 117602 (Singapore); Tok, Eng Soon [Physics Department, National University of Singapore, 117542 (Singapore); Yang, C.S. [Center for Nanomedicine, National Health Research Institutes, Miaoli 350, Taiwan (China); Margaritondo, G. [Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne (Switzerland); Hwu, Y., E-mail: phhwu@sinica.edu.tw [Institute of Physics, Academia Sinica, Taipei 115, Taiwan (China); Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan 701, Taiwan (China); Institute of Optoelectronic Sciences, National Taiwan Ocean University, Keelung 202, Taiwan (China)

2015-01-15

We show that by using different x-ray irradiation times of BSA-coated Au nanoparticles (NPs) we can change their ultraviolet-stimulated photoluminescence and shift the spectral weight over the visible spectral range. This is due to the interplay of two emission bands, one due to BSA and the other related to gold. The emission properties did not change with time over a period of several months. - Highlights: • Gold nanoparticles (Au NPs) coated with Bovine Serum Albumin (BSA) are synthesized by x-ray irradiation. • BSA coated AuNPs with ∼1 nm size show strong photoluminescence in red by UV excitation. • The blue photoluminescence of BSA increase with x-ray irradiation. • Increase x-ray irradiation time during the synthesis shift the color of the colloid from red to blue.

Gold nanoparticles: BSA (Bovine Serum Albumin) coating and X-ray irradiation produce variable-spectrum photoluminescence

International Nuclear Information System (INIS)

Lee, Kuo-Hao; Lai, Sheng-Feng; Lin, Yan-Cheng; Chou, Wu-Ching; Ong, Edwin B.L.; Tan, Hui-Ru; Tok, Eng Soon; Yang, C.S.; Margaritondo, G.; Hwu, Y.

2015-01-01

We show that by using different x-ray irradiation times of BSA-coated Au nanoparticles (NPs) we can change their ultraviolet-stimulated photoluminescence and shift the spectral weight over the visible spectral range. This is due to the interplay of two emission bands, one due to BSA and the other related to gold. The emission properties did not change with time over a period of several months. - Highlights: • Gold nanoparticles (Au NPs) coated with Bovine Serum Albumin (BSA) are synthesized by x-ray irradiation. • BSA coated AuNPs with ∼1 nm size show strong photoluminescence in red by UV excitation. • The blue photoluminescence of BSA increase with x-ray irradiation. • Increase x-ray irradiation time during the synthesis shift the color of the colloid from red to blue

Laser-assisted coating of TI6AL4V substrate with Zinc

CSIR Research Space (South Africa)

Baloyi, NM

2012-12-01

Full Text Available Laser coating is an advanced coating technology used for improving the surface properties of metal components. The coatings produced are thick, dense, and crack-free with continuous non-porous microstructures having uniform composition which results...

FABRICATION OF GAS-FILLED TUNGSTEN-COATED GLASS SHELLS

International Nuclear Information System (INIS)

NIKROO, A; BAUGH, W; STEINMAN, D.A.

2003-09-01

OAK-B135 Deuterium (D 2 ) filled glass shells coated with a high Z element are needed for high energy density (HED) experiments by researchers at Los Alamos National Laboratory. They report here on our initial attempt to produce such shells. Glass shells made using the drop tower technique were coated with gold, palladium or tungsten, or a mixture of two of these elements. It was found that gold and palladium coatings did not stick well to the glass and resulted in poor or delaminated films. Tungsten coatings resulted in films suitable for these targets. Bouncing of shells during coating resulted in uniform tungsten coatings, but the surface of such coatings were filled with small nodules. Proper agitation of shells using a tapping technique resulted in smooth films with minimal particulate contamination. For coating rates of ∼ 0.15 (micro)m/hr coatings with ∼ 2 nm RMS surface finish could be deposited. The surface roughness of coatings at higher rates, 0.7 (micro)m/hr, was considerably worse (∼ 100 nm RMS). The columnar structure of the coatings allowed permeation filling of the tungsten coated glass shells with deuterium at 300 C

Biomedical coatings on magnesium alloys - a review.

Science.gov (United States)

Hornberger, H; Virtanen, S; Boccaccini, A R

2012-07-01

This review comprehensively covers research carried out in the field of degradable coatings on Mg and Mg alloys for biomedical applications. Several coating methods are discussed, which can be divided, based on the specific processing techniques used, into conversion and deposition coatings. The literature review revealed that in most cases coatings increase the corrosion resistance of Mg and Mg alloys. The critical factors determining coating performance, such as corrosion rate, surface chemistry, adhesion and coating morphology, are identified and discussed. The analysis of the literature showed that many studies have focused on calcium phosphate coatings produced either using conversion or deposition methods which were developed for orthopaedic applications. However, the control of phases and the formation of cracks still appear unsatisfactory. More research and development is needed in the case of biodegradable organic based coatings to generate reproducible and relevant data. In addition to biocompatibility, the mechanical properties of the coatings are also relevant, and the development of appropriate methods to study the corrosion process in detail and in the long term remains an important area of research. Copyright © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Wear behaviour of plasma-sprayed AlSi/B4C composite coatings

International Nuclear Information System (INIS)

Sarikaya, Ozkan; Anik, Selahaddin; Celik, Erdal; Okumus, S. Cem; Aslanlar, Salim

2007-01-01

This paper describes the wear behaviour of AlSi/B 4 C composite coatings with 0-25 wt% B 4 C particles for diesel engine motors. These coatings were successfully fabricated on AlSi substrates using an atmospheric plasma spray technique. The produced samples were characterized by means of an optical microscope, scanning electron microscope and microhardness tester. The obtained results pointed out that an increase of B 4 C particles in AlSi coatings was caused on the rising of the microhardness values and the decrease of the thermal expansion coefficient of the coatings. The friction and wear experiments were performed under dry conditions using a ball-on-dics configuration against WC/Co counter material for different loads. It was concluded that wear resistance of the coatings produced using B 4 C powders is greatly improved compared with the substrate material. The highest wear resistance of the coatings were also determined in the 20% B 4 C coating

The Effect of Surfactant Content over Cu-Ni Coatings Electroplated by the sc-CO₂ Technique.

Science.gov (United States)

Chuang, Ho-Chiao; Sánchez, Jorge; Cheng, Hsiang-Yun

2017-04-19

Co-plating of Cu-Ni coatings by supercritical CO₂ (sc-CO₂) and conventional electroplating processes was studied in this work. 1,4-butynediol was chosen as the surfactant and the effects of adjusting the surfactant content were described. Although the sc-CO₂ process displayed lower current efficiency, it effectively removed excess hydrogen that causes defects on the coating surface, refined grain size, reduced surface roughness, and increased electrochemical resistance. Surface roughness of coatings fabricated by the sc-CO₂ process was reduced by an average of 10%, and a maximum of 55%, compared to conventional process at different fabrication parameters. Cu-Ni coatings produced by the sc-CO₂ process displayed increased corrosion potential of ~0.05 V over Cu-Ni coatings produced by the conventional process, and 0.175 V over pure Cu coatings produced by the conventional process. For coatings ~10 µm thick, internal stress developed from the sc-CO₂ process were ~20 MPa lower than conventional process. Finally, the preferred crystal orientation of the fabricated coatings remained in the (111) direction regardless of the process used or surfactant content.

Characterization and mechanical properties of coatings on magnesium by micro arc oxidation

International Nuclear Information System (INIS)

Durdu, Salih; Usta, Metin

2012-01-01

Highlights: ► The commercial pure magnesium was coated by MAO in sodium silicate and sodium phosphate. ► Coatings produced in the phosphate electrolyte are thicker than ones in the silicate electrolyte. ► Coatings in the silicate electrolyte are harder than ones in the phosphate electrolyte. ► Adhesion strength of coatings increases with increasing coating thickness. ► The wear resistance of the coated commercial pure magnesium is improved. - Abstracts: The commercial pure magnesium was coated by micro arc oxidation method in different aqueous solution, containing sodium silicate and sodium phosphate. Micro arc oxidation process was carried out at 0.060 A/cm 2 , 0.085 A/cm 2 and 0.140 A/cm 2 current densities for 30 min. The thickness, phase composition, morphology, hardness, adhesion strength and wear resistance of coatings were analyzed by eddy current, X-ray diffraction (XRD), scanning electron microscope (SEM), micro hardness tester, scratch tester and ball-on disk tribometer, respectively. The average thicknesses of the micro arc oxidized coatings ranged from 27 to 48 μm for sodium silicate solution and from 45 to 75 μm for sodium phosphate solution. The dominant phases formed on the pure magnesium were found to be a mixture of spinel Mg 2 SiO 4 (Forsterite) and MgO (Periclase) for sodium silicate solution and Mg 3 (PO 4 ) 2 (Farringtonite) and MgO (Periclase) for sodium phosphate solution. The average hardnesses of the micro arc oxidized coatings were between 260 HV and 470 HV for sodium silicate solution and between 175 HV and 260 HV for sodium phosphate solution. Adhesion strengths and wear resistances of coatings produced in sodium silicate solution were higher than those of the ones in sodium phosphate solution due to high hardness of coatings produced in sodium silicate solution.

Silver doped hydroxyapatite coatings by sacrificial anode deposition under magnetic field.

Science.gov (United States)

Swain, S; Rautray, T R

2017-09-13

Uniform distribution of silver (Ag) in the hydroxyapatite (HA) coated Ti surface has been a concern for which an attempt has been made to dope Ag in HA coating with and without magnetic field. Cathodic deposition technique was employed to coat Ag incorporated hydroxyapatite coating using a sacrificial silver anode method by using NdFeB bar magnets producing 12 Tesla magnetic field. While uniform deposition of Ag was observed in the coatings under magnetic field, dense coating was evident in the coating without magnetic field conditions. Uniformly distributed Ag incorporated HA in the present study has potential to fight microorganism while providing osseoconduction properties of the composite coating.

Oxidation study of Ta–Zr coatings

Energy Technology Data Exchange (ETDEWEB)

Chen, Yung-I, E-mail: yichen@mail.ntou.edu.tw; Chen, Sin-Min

2013-02-01

Refractory metal alloy coatings, such as Mo–Ru and Ta–Ru coatings, have been developed to protect glass molding dies. Forming intermetallic compounds in the coatings inhibits grain growth in high temperature environments when mass producing optical components. After annealing in oxygen containing atmospheres, a surface roughening of the Mo–Ru coatings and a soft oxide layer on the Ta–Ru coatings have been observed in our previous works. Oxidation resistance becomes critical in high-temperature applications. In this study, Ta–Zr coatings were deposited with a Ti interlayer on silicon wafers using direct current magnetron sputtering at 400 °C. The as-deposited Ta–Zr coatings possessed nanocrystallite or amorphous states, depending on the chemical compositions. The annealing treatments were conducted at 600 °C under atmospheres of 50 ppm O{sub 2}–N{sub 2} or 1% O{sub 2}–Ar, respectively. After the annealing treatment, this study investigated variations in crystalline structure, hardness, surface roughness, and chemical composition profiles. Preferential oxidation of Zr in the Ta–Zr coatings was verified using X-ray photoelectron spectroscopy, and the microstructure was observed using transmission electron microscopy. - Highlights: ►The as-deposited Ta-rich Ta–Zr coatings revealed an amorphous structure. ►The Zr-rich coatings presented a crystalline β-Zr phase and an amorphous matrix. ►Zr oxidized preferentially as Ta–Zr coatings annealed at 600 °C. ►The hardness of coatings revealed a parabolic relationship with the oxygen content. ►A protective oxide scale formed on the surface of the crystallized Zr-rich coatings.

Feasibility of preparing patterned molybdenum coatings on bismuth telluride thermoelectric modules.

Energy Technology Data Exchange (ETDEWEB)

Sarobol, Pylin; Hall, Aaron Christopher; Miller, Stephen Samuel; Knight, Marlene E.; LePage, William S.; Sobczak, Catherine Elizabeth.; Wesolowski, Daniel Edward

2013-09-01

Molybdenum electrical interconnects for thermoelectric modules were produced by air plasma spraying a 30%CE%BCm size molybdenum powder through a laser-cut Kapton tape mask. Initial feasibility demonstrations showed that the molybdenum coating exhibited excellent feature and spacing retention (~170%CE%BCm), adhered to bismuth-telluride, and exhibited electrical conductivity appropriate for use as a thermoelectric module interconnect. A design of experiments approach was used to optimize air plasma spray process conditions to produce a molybdenum coating with low electrical resistivity. Finally, a molybdenum coating was successfully produced on a fullscale thermoelectric module. After the addition of a final titanium/gold layer deposited on top of the molybdenum coating, the full scale module exhibited an electrical resistivity of 128%CE%A9, approaching the theoretical resistivity value for the 6mm module leg of 112%CE%A9. Importantly, air plasma sprayed molybdenum did not show significant chemical reaction with bismuth-telluride substrate at the coating/substrate interface. The molybdenum coating microstructure consisted of lamellar splats containing columnar grains. Air plasma sprayed molybdenum embedded deeply (several microns) into the bismuth-telluride substrate, leading to good adhesion between the coating and the substrate. Clusters of round pores (and cracks radiating from the pores) were found immediately beneath the molybdenum coating. These pores are believed to result from tellurium vaporization during the spray process where the molten molybdenum droplets (2623%C2%B0C) transferred their heat of solidification to the substrate at the moment of impact. Substrate cooling during the molybdenum deposition process was recommended to mitigate tellurium vaporization in future studies.

Effect of Image Linearization on Normalized Compression Distance

Science.gov (United States)

Mortensen, Jonathan; Wu, Jia Jie; Furst, Jacob; Rogers, John; Raicu, Daniela

Normalized Information Distance, based on Kolmogorov complexity, is an emerging metric for image similarity. It is approximated by the Normalized Compression Distance (NCD) which generates the relative distance between two strings by using standard compression algorithms to compare linear strings of information. This relative distance quantifies the degree of similarity between the two objects. NCD has been shown to measure similarity effectively on information which is already a string: genomic string comparisons have created accurate phylogeny trees and NCD has also been used to classify music. Currently, to find a similarity measure using NCD for images, the images must first be linearized into a string, and then compared. To understand how linearization of a 2D image affects the similarity measure, we perform four types of linearization on a subset of the Corel image database and compare each for a variety of image transformations. Our experiment shows that different linearization techniques produce statistically significant differences in NCD for identical spatial transformations.

SiO2 coating of silver nanoparticles by photoinduced chemical vapor deposition

International Nuclear Information System (INIS)

Boies, Adam M; Girshick, Steven L; Roberts, Jeffrey T; Zhang Bin; Nakamura, Toshitaka; Mochizuki, Amane

2009-01-01

Gas-phase silver nanoparticles were coated with silicon dioxide (SiO 2 ) by photoinduced chemical vapor deposition (photo-CVD). Silver nanoparticles, produced by inert gas condensation, and a SiO 2 precursor, tetraethylorthosilicate (TEOS), were exposed to vacuum ultraviolet (VUV) radiation at atmospheric pressure and varying temperatures. The VUV photons dissociate the TEOS precursor, initiating a chemical reaction that forms SiO 2 coatings on the particle surfaces. Coating thicknesses were measured for a variety of operation parameters using tandem differential mobility analysis and transmission electron microscopy. The chemical composition of the particle coatings was analyzed using energy dispersive x-ray spectrometry and Fourier transform infrared spectroscopy. The highest purity films were produced at 300-400 0 C with low flow rates of additional oxygen. The photo-CVD coating technique was shown to effectively coat nanoparticles and limit core particle agglomeration at concentrations up to 10 7 particles cm -3 .

Structure and Corrosion Behavior of Arc-Sprayed Zn-Al Coatings on Ductile Iron Substrate

Science.gov (United States)

Bonabi, Salar Fatoureh; Ashrafizadeh, Fakhreddin; Sanati, Alireza; Nahvi, Saied Mehran

2018-02-01

In this research, four coatings including pure zinc, pure aluminum, a double-layered coating of zinc and aluminum, and a coating produced by simultaneous deposition of zinc and aluminum were deposited on a cast iron substrate using electric arc-spraying technique. The coatings were characterized by XRD, SEM and EDS map and spot analyses. Adhesion strength of the coatings was evaluated by three-point bending tests, where double-layered coating indicated the lowest bending angle among the specimens, with detection of cracks at the coating-substrate interface. Coatings produced by simultaneous deposition of zinc and aluminum possessed a relatively uniform distribution of both metals. In order to evaluate the corrosion behavior of the coatings, cyclic polarization and salt spray tests were conducted. Accordingly, pure aluminum coating showed susceptibility to pitting corrosion and other coatings underwent uniform corrosion. For double-layered coating, SEM micrographs revealed zinc corrosion products as flaky particles in the pores formed by pitting on the surface, an indication of penetration of corrosion products from the lower layer (zinc) to the top layer (aluminum). All coatings experienced higher negative corrosion potentials than the iron substrate, indicative of their sacrificial behavior.

Microhardness and wear resistance of PEO-coated 5754 aluminum alloy

Science.gov (United States)

Vyaliy, I. E.; Egorkin, V. S.; Sinebryukhov, S. L.; Minaev, A. N.; Gnedenkov, S. V.

2017-09-01

We present results of the study aimed at assessing the effect of duty cycle (D) during plasma electrolytic oxidation (PEO) on protective properties of the coatings produced on 5754 aluminum alloy. It is shown that increasing the duty cycle of a microsecond current pulses leads to increased hardness and reduced abrasive wear of the PEO-layers, improving mechanical properties. The obtained data allowed confirming, that increasing the amount of energy consumed for coating growth leads to the formation of thicker PEO-layers with improved tribological properties. The effect of duty cycle during plasma electrolytic oxidation on protective properties of the produced coatings was assessed.

Coating material composition

International Nuclear Information System (INIS)

Kimura, Tadashi; Ozeki, Takao; Kobayashi, Juichi; Nakamoto, Hideo; Maeda, Yutaka.

1969-01-01

A coating material composition is provided which can easily be cross-linked by irradiation with active energy, particularly electron beams and ultraviolet light, using a mixture of a prepolymer (a) with an addition reaction product (b). Such compositions have coating properties as good as thermosetting acrylic or amino alkyd resins. The prepolymer (a) is produced by primarily reacting at least 0.1 mol of saturated cyclocarboxylic acid anhydrides and/or alpha-, beta-ethylene unsaturated carboxylic acid anhydrides by addition reaction with one mol of hydroxyl radicals of a basic polymer having a molecular weight of 1,000 to 100,000, the basic polymer being obtained from 1%-40% of a hydroxyl radical containing vinyl monomer and at least 30% of (meth)acrylate monomer. One mol of the sum of hydroxyl radicals and carboxyl radicals of the primary reaction product undergoes a secondary addition reaction with at least 0.1 mol of an epoxy radical-containing vinyl monomer to form the prepolymer(a). The addition reaction product(b) is produced by reacting an epoxy radical-containing vinyl monomer with alpha-, beta-ethylene unsaturated carboxylic acids or their anhydrides. The coating material composition contains a majority of a mixture consisting of 10%-90% of (a) and 90%-10% of (b) above by weight. Four examples of the production of basic polymers, seven examples of the production of prepolymers, seven examples of the production of oligomers, and five examples of applications are given. (Iwakiri, K.)

Thick boron carbide coatings for protection of tokamak first wall and divertor

International Nuclear Information System (INIS)

Buzhinskij, O.I.; Semenets, Yu.M.

1999-01-01

A review of characteristics of various types of boron carbide coatings considered as candidate materials for protection of tokamak inner surfaces against high energy heat fluxes is presented. Such coatings are produced by various methods: chemical vapor deposition by means of chloride and fluoride techniques, gas conversion, plasma spray and reaction-sintering. Contrary to pure carbon materials, B 4 C has much lower chemical and high-temperature sputtering, is capable to oxygen gettering and lower hydrogen recycling. In contrast to thin boronization films, the thick coatings can resist high heat fluxes such as in tokamak divertors. Comparative analysis shows that coatings produced by the diffusion methods, such as fluoride CVD and gas conversion, are more resistent to heat loads, and one of the most promising candidates are the fluoride CVD coatings. (orig.)

“m=1” coatings

DEFF Research Database (Denmark)

Cooper-Jensen, C.; Klinkby, Esben Bryndt; Beaucour, J.

For neutrons the critical angle of Ni is defined as m=1. If one needs a coating with reflectivity above m=1, people have traditionally used Ni58 or Ni-based multilayers. The reason to use Ni is the high neutron scattering density and the fact that it is easy to coat Ni using magnetron sputtering....... For a neutron guide the cost of shielding around the guide is a substantial part of the total cost of the guide. We are therefore looking at other materials than Ni for m=1 coatings. Both Be and diamond have the same or higher neutron scattering density than Ni, and have a much smaller absorption cross section....... Because of the lower absorption cross section, and because of fewer emitted gamma ray photons when a neutron is absorbed, these coatings are producing much less gamma radiation and therefore reduce the shielding costs. Be is frequently used in a wide range of science and technology applications. The only...

Polymer coatings as separator layers for microbial fuel cell cathodes

KAUST Repository

Watson, Valerie J.

2011-03-01

Membrane separators reduce oxygen flux from the cathode into the anolyte in microbial fuel cells (MFCs), but water accumulation and pH gradients between the separator and cathode reduces performance. Air cathodes were spray-coated (water-facing side) with anion exchange, cation exchange, and neutral polymer coatings of different thicknesses to incorporate the separator into the cathode. The anion exchange polymer coating resulted in greater power density (1167 ± 135 mW m-2) than a cation exchange coating (439 ± 2 mW m-2). This power output was similar to that produced by a Nafion-coated cathode (1114 ± 174 mW m-2), and slightly lower than the uncoated cathode (1384 ± 82 mW m-2). Thicker coatings reduced oxygen diffusion into the electrolyte and increased coulombic efficiency (CE = 56-64%) relative to an uncoated cathode (29 ± 8%), but decreased power production (255-574 mW m-2). Electrochemical characterization of the cathodes ex situ to the MFC showed that the cathodes with the lowest charge transfer resistance and the highest oxygen reduction activity produced the most power in MFC tests. The results on hydrophilic cathode separator layers revealed a trade off between power and CE. Cathodes coated with a thin coating of anion exchange polymer show promise for controlling oxygen transfer while minimally affecting power production. © 2010 Elsevier B.V. All rights reserved.

Porous Structure Characterization in Titanium Coating for Surgical Implants

Directory of Open Access Journals (Sweden)

M.V. Oliveira

2002-09-01

Full Text Available Powder metallurgy techniques have been used to produce controlled porous structures, such as the porous coatings applied for dental and orthopedic surgical implants, which allow bony tissue ingrowth within the implant surface improving fixation. This work presents the processing and characterization of titanium porous coatings of different porosity levels, processed through powder metallurgy techniques. Pure titanium sponge powders were used for coating and Ti-6Al7Nb powder metallurgy rods were used as substrates. Characterization was made through quantitative metallographic image analysis using optical light microscope for coating porosity data and SEM analysis for evaluation of the coating/substrate interface integrity. The results allowed optimization of the processing parameters in order to obtain porous coatings that meet the requirements for use as implants.

Biomimetic calcium phosphate coatings on recombinant spider silk fibres

Energy Technology Data Exchange (ETDEWEB)

Yang Liang; Habibovic, Pamela; Van Blitterswijk, Clemens A [Department of Tissue Regeneration, University of Twente, PO Box 217, 7500 AE Enschede (Netherlands); Hedhammar, My; Johansson, Jan [Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, the Biomedical Centre, Box 575, 751 23 Uppsala (Sweden); Blom, Tobias; Leifer, Klaus [Department of Engineering Sciences, Uppsala University, Box 534, S-751 21 Uppsala (Sweden)

2010-08-01

Calcium phosphate ceramic coatings, applied on surfaces of metallic and polymeric biomaterials, can improve their performance in bone repair and regeneration. Spider silk is biocompatible, strong and elastic, and hence an attractive biomaterial for applications in connective tissue repair. Recently, artificial spider silk, with mechanical and structural characteristics similar to those of native spider silk, has been produced from recombinant minispidroins. In the present study, supersaturated simulated body fluid was used to deposit calcium phosphate coatings on recombinant spider silk fibres. The mineralization process was followed in time using scanning electron microscopy equipped with an energy dispersive x-ray (EDX) detector and Raman spectroscope. Focused ion beam technology was used to produce a cross section of a coated fibre, which was further analysed by EDX. Preliminary in vitro experiments using a culture of bone marrow-derived human mesenchymal stem cells (hMSCs) on coated fibres were also performed. This study showed that recombinant spider silk fibres were successfully coated with a homogeneous and thick crystalline calcium phosphate layer. In the course of the mineralization process from modified simulated body fluid, sodium chloride crystals were first deposited on the silk surface, followed by the deposition of a calcium phosphate layer. The coated silk fibres supported the attachment and growth of hMSCs.

Biomimetic calcium phosphate coatings on recombinant spider silk fibres

International Nuclear Information System (INIS)

Yang Liang; Habibovic, Pamela; Van Blitterswijk, Clemens A; Hedhammar, My; Johansson, Jan; Blom, Tobias; Leifer, Klaus

2010-01-01

Calcium phosphate ceramic coatings, applied on surfaces of metallic and polymeric biomaterials, can improve their performance in bone repair and regeneration. Spider silk is biocompatible, strong and elastic, and hence an attractive biomaterial for applications in connective tissue repair. Recently, artificial spider silk, with mechanical and structural characteristics similar to those of native spider silk, has been produced from recombinant minispidroins. In the present study, supersaturated simulated body fluid was used to deposit calcium phosphate coatings on recombinant spider silk fibres. The mineralization process was followed in time using scanning electron microscopy equipped with an energy dispersive x-ray (EDX) detector and Raman spectroscope. Focused ion beam technology was used to produce a cross section of a coated fibre, which was further analysed by EDX. Preliminary in vitro experiments using a culture of bone marrow-derived human mesenchymal stem cells (hMSCs) on coated fibres were also performed. This study showed that recombinant spider silk fibres were successfully coated with a homogeneous and thick crystalline calcium phosphate layer. In the course of the mineralization process from modified simulated body fluid, sodium chloride crystals were first deposited on the silk surface, followed by the deposition of a calcium phosphate layer. The coated silk fibres supported the attachment and growth of hMSCs.

Effects of laser radiation on surfaces and coatings

International Nuclear Information System (INIS)

Lowdermilk, W.H.

1985-01-01

A summary is given of the principal aspects of laser-induced damage to polished optical surfaces and dielectric, thin-film, high-reflectivity and antireflective coatings. Methods for producing porous antireflective surfaces and coatings and their damage properties are also reviewed. Finally, new areas of basic research to solve current and future problems are addressed

Super-low friction behavior of nanostructured DLC composite coatings

NARCIS (Netherlands)

Pei, Y.T.; Galvan, D.; de Hosson, J.T.M.; DeHosson, JTM; Brebbia, CA; Nishida, SI

2005-01-01

Advanced TiC/a-C:H nanocomposite coatings have been produced via reactive deposition in a closed-field unbalanced magnetron sputtering system (Hauzer HTC-1000). This work concentrates on a detailed mechanical and tribological characterization of the TiC/a-C:H nanocomposite coatings, in particular

Coating of ceramic powders by chemical vapor deposition techniques (CVD)

International Nuclear Information System (INIS)

Haubner, R.; Lux, B.

1997-01-01

New ceramic materials with selected advanced properties can be designed by coating of ceramic powders prior to sintering. By variation of the core and coating material a large number of various powders and ceramic materials can be produced. Powders which react with the binder phase during sintering can be coated with stable materials. Thermal expansion of the ceramic materials can be adjusted by varying the coating thickness (ratio core/layer). Electrical and wear resistant properties can be optimized for electrical contacts. A fluidized bed reactor will be designed which allow the deposition of various coatings on ceramic powders. (author)

Diamond-like carbon coated ultracold neutron guides

International Nuclear Information System (INIS)

Heule, S.; Atchison, F.; Daum, M.; Foelske, A.; Henneck, R.; Kasprzak, M.; Kirch, K.; Knecht, A.; Kuzniak, M.; Lippert, T.; Meier, M.; Pichlmaier, A.; Straumann, U.

2007-01-01

It has been shown recently that diamond-like carbon (DLC) with a sp 3 fraction above 60% is a better wall coating material for ultracold neutron applications than beryllium. We report on results of Raman spectroscopic and XPS measurements obtained for diamond-like carbon coated neutron guides produced in a new facility, which is based on pulsed laser deposition at 193 nm. For diamond-like carbon coatings on small stainless steel substrates we find sp 3 fractions in the range from 60 to 70% and showing slightly increasing values with laser pulse energy and pulse repetition rate

IMPACT OF NUTRITIONAL COUNSELLING ON BODY MASS INDEX (BMI AND NUTRIENT INTAKE OF THE NON - COMMUNICABLE DISEASE PATIENTS (NCD

Directory of Open Access Journals (Sweden)

Manisha Singh

2011-12-01

Full Text Available Good health is an important discussion of the quality of life. Health problem is a major concern in all over the world but especially in developing countries. Non-communicable diseases ( NCDs contribute the ill health. Diabetes, coronary heart disease, various forms of cancer, gastro intestinal disorder and various diseases of bones and joints are diet related NCDs. Nutritional counselling is one of the effective tools of changing the food habits of people. The data for this study is taken from the out patients services of Department of Endocrinology & Metabolism and Cardiology of Sir Sunder Lal Hospital, Banaras Hindu University, Varanasi-5. Total 250 samples were included in the study. Age group 40 – 60 years were considered as study samples who attended the Endocrinology and Cardiology departments. Purposive sampling method was used in the study. Questionnaire cum interview method was adopted in the study. Anthropametric measurements were taken by using standard techniques. 24 hours diet recall method was also used in this study. Evaluation of councelling was done on basis of changes in BMI and nutrient intake. Result shows the positive impact of nutritional counselling in BMI and nutrient intake of NCD patients.

Material-Process-Performance Relationships for Roll-to-Roll Coated PEM Electrodes

Energy Technology Data Exchange (ETDEWEB)

Mauger, Scott; Neyerlin, K.C.; Stickel, Jonathan; Ulsh, Michael; More, Karren; Wood, David

2017-04-26

Roll-to-roll (R2R) coating is the most economical and highest throughput method for producing fuel cell electrodes. R2R coating encompasses many different methodologies to create uniform films on a moving web substrate. Here we explore two coating methods, gravure and slot die, to understand the impacts of each on film uniformity and performance.

Vanadium carbide coatings: deposition process and properties

International Nuclear Information System (INIS)

Borisova, A.; Borisov, Y.; Shavlovsky, E.; Mits, I.; Castermans, L.; Jongbloed, R.

2001-01-01

Vanadium carbide coatings on carbon and alloyed steels were produced by the method of diffusion saturation from the borax melt. Thickness of the vanadium carbide layer was 5-15 μm, depending upon the steel grade and diffusion saturation parameters. Microhardness was 20000-28000 MPa and wear resistance of the coatings under conditions of end face friction without lubrication against a mating body of WC-2Co was 15-20 times as high as that of boride coatings. Vanadium carbide coatings can operate in air at a temperature of up to 400 o C. They improve fatigue strength of carbon steels and decrease the rate of corrosion in sea and fresh water and in acid solutions. The use of vanadium carbide coatings for hardening of various types of tools, including cutting tools, allows their service life to be extended by a factor of 3 to 30. (author)

Copper-coated laser-fusion targets using molecular-beam levitation

International Nuclear Information System (INIS)

Rocke, M.J.

1981-01-01

A series of diagnostic experiments at the Shiva laser fusion facility required targets of glass microspheres coated with 1.5 to 3.0 μm of copper. Previous batch coating efforts using vibration techniques gave poor results due to microsphere sticking and vacuum welding. Molecular Beam Levitation (MBL) represented a noncontact method to produce a sputtered copper coating on a single glassmicrosphere. The coating specifications that were achieved resulted in a copper layer up to 3 μm thick with the allowance of a maximum variation of 10 nm in surface finish and thickness. These techniques developed with the MBL may be applied to sputter coat many soft metals for fusion target applications

Stronger multilayer acrylic dielectric elastomer actuators with silicone gel coatings

Science.gov (United States)

Lau, Gih-Keong; La, Thanh-Giang; Sheng-Wei Foong, Ervin; Shrestha, Milan

2016-12-01

Multilayer dielectric elastomer actuators (DEA) perform worst off than single-layer DEAs due to higher susceptibility to electro-thermal breakdown. This paper presents a hot-spot model to predict the electro-thermal breakdown field of DEAs and its dependence on thermal insulation. To inhibit the electrothermal breakdown, silicone gel coating was applied as barrier coating to multilayer acrylic DEA. The gel coating helps suppress the electro-thermally induced puncturing of DEA membrane at the hot spot. As a result, the gel-coated DEAs, in either a single layer or a multilayer stack, can produce 30% more isometric stress change as compared to those none-coated. These gel-coated acrylic DEAs show great potential to make stronger artificial muscles.

Residual Strain Characteristics of Nickel-coated FBG Sensors

International Nuclear Information System (INIS)

Cho, Won-Jae; Hwang, A-Reum; Kim, Sang-Woo

2017-01-01

A metal-coated FBG (fiber Bragg grating) sensor has a memory effect, which can recall the maximum strains experienced by the structure. In this study, a nickel-coated FBG sensor was fabricated through electroless (i.e., chemical plating) and electroplating. A thickness of approximately 43 μm of a nickel layer was achieved. Then, we conducted cyclic loading tests for the fabricated nickel-coated FBG sensors to verify their capability to produce residual strains. The results revealed that the residual strain induced by the nickel coating linearly increased with an increase in the maximum strain experienced by the sensor. Therefore, we verified that a nickel-coated FBG sensor has a memory effect. The fabrication methods and the results of the cycle loading test will provide basic information and guidelines in the design of a nickel-coated FBG sensor when it is applied in the development of structural health monitoring techniques.

Residual Strain Characteristics of Nickel-coated FBG Sensors

Energy Technology Data Exchange (ETDEWEB)

Cho, Won-Jae; Hwang, A-Reum; Kim, Sang-Woo [Hankyong National Univ., Ansung (Korea, Republic of)

2017-07-15

A metal-coated FBG (fiber Bragg grating) sensor has a memory effect, which can recall the maximum strains experienced by the structure. In this study, a nickel-coated FBG sensor was fabricated through electroless (i.e., chemical plating) and electroplating. A thickness of approximately 43 μm of a nickel layer was achieved. Then, we conducted cyclic loading tests for the fabricated nickel-coated FBG sensors to verify their capability to produce residual strains. The results revealed that the residual strain induced by the nickel coating linearly increased with an increase in the maximum strain experienced by the sensor. Therefore, we verified that a nickel-coated FBG sensor has a memory effect. The fabrication methods and the results of the cycle loading test will provide basic information and guidelines in the design of a nickel-coated FBG sensor when it is applied in the development of structural health monitoring techniques.

Decomposition of dual hydroxyapatite/fluoroapatite coatings on metal substrates

International Nuclear Information System (INIS)

Wei, M.; Evans, J.H.; Wentrup-Byrne, E.

2000-01-01

In order to prevent the formation of tricalcium phosphate (TCP), a relatively weak and rapidly biodegradable biomaterial, during sintering of hydroxyapatite (Hap) onto metal substrates, a novel two layer coating was applied. This was achieved by pre-coating the substrate with either Hap or fluorapatite (Fap) which preserved the purity of the Hap top coating. However, Fap is more stable thermally than Hap. The composition of Hap and Fap were determined by x-ray diffraction and infrared spectroscopy. A scanning electron microscope was also used to characterise the surface morphologiy of the coatings. By using Fap the formation of TCP was totally prevented through out the coatings at a sintering temperature of 1050 deg C at which a relatively dense Hap outer coating was produced. Copyright (2000) The Australian Ceramic Society

Study the polymer coating for detecting and surface decontamination of uranium

International Nuclear Information System (INIS)

Pham Thi Quynh Luong; Nguyen Van Chinh

2011-01-01

Strippable polymer coating is one of the methods for effective surface decontamination. It has been developed in both detecting and removing the radioactive isotope and heavy metal elements from contaminated surfaces. A polymer coating is produced to be sprayed or brushed on contaminated material of uranium. The places of U contamination is shown by color change of polymer coating. As the polymer coating is dried up to form a strong film, the contaminations are absorbed in to the coating and contaminated surfaces are cleaned by removing the film. (author)

Coating with the aid of a plasmatron

International Nuclear Information System (INIS)

Huebner, D.; Reissmueller, L.

1984-01-01

Subject of the invention is the coating of sensitive semiconductor elements with the aid of a plasmatron in such a way that a layer of uniform chemical composition, adequate adhesion and resistance to following treatments results. This could be achieved by producing a first layer of about 10% of the thickness needed with low-energy ions. In the second coating step the layer is completed through ions of high energy

Whole blood treated with riboflavin and ultraviolet light: quality assessment of all blood components produced by the buffy coat method.

Science.gov (United States)

Schubert, Peter; Culibrk, Brankica; Karwal, Simrath; Serrano, Katherine; Levin, Elena; Bu, Daniel; Bhakta, Varsha; Sheffield, William P; Goodrich, Raymond P; Devine, Dana V

2015-04-01

Pathogen inactivation (PI) technologies are currently licensed for use with platelet (PLT) and plasma components. Treatment of whole blood (WB) would be of benefit to the blood banking community by saving time and costs compared to individual component treatment. However, no paired, pool-and-split study directly assessing the impact of WB PI on the subsequently produced components has yet been reported. In a "pool-and-split" study, WB either was treated with riboflavin and ultraviolet (UV) light or was kept untreated as control. The buffy coat (BC) method produced plasma, PLT, and red blood cell (RBC) components. PLT units arising from the untreated WB study arm were treated with riboflavin and UV light on day of production and compared to PLT concentrates (PCs) produced from the treated WB units. A panel of common in vitro variables for the three types of components was used to monitor quality throughout their respective storage periods. PCs derived from the WB PI treatment were of significantly better quality than treated PLT components for most variables. RBCs produced from the WB treatment deteriorated earlier during storage than untreated units. Plasma components showed a 3% to 44% loss in activity for several clotting factors. Treatment of WB with riboflavin and UV before production of components by the BC method shows a negative impact on all three blood components. PLT units produced from PI-treated WB exhibited less damage compared to PLT component treatment. © 2014 AABB.

Characterization of hard nitride and carbide titanium and zirconium coatings on high-speed steel cutting tool inserts

International Nuclear Information System (INIS)

Fenske, G.; Kaufherr, N.; Albertson, C.; Mapalo, G.; Nielsen, R.; Kaminsky, M.

1986-01-01

Hard nitride and carbide coatings of titanium and zirconium deposited by reactive evaporation and reactive sputtering techniques were characterized by electron microscopy and Auger spectroscopy to determine the effect of coating process on coating composition and microstructure. Analysis of the chemical composition by Auger spectroscopy revealed the coatings were of high purity with slight differences in stoichiometry depending on the coating technique. Both techniques produced coatings with a columnar microstructure. However, the reactive sputtering technique produced coarser (shorter and wider) columnar grains than the reactive evaporation technique. Furthermore, selected area diffraction analysis of reactively sputtered ZrN coatings showed a two-phased zone (hcp Zr and fcc ZrN) near the substrate/coating interface, while TiC coatings deposited by reactive sputtering and evaporation only showed a single-phase region of fcc TiC

Characterization and formation of hydroxyapatite on Ti6Al4V coated by plasma electrolytic oxidation

International Nuclear Information System (INIS)

Durdu, Salih; Deniz, Ömer Faruk; Kutbay, Işıl; Usta, Metin

2013-01-01

Highlights: ► Ti6Al4V alloys were coated by PEO in calcium acetate and β-calcium glycerophosphate. ► Hydroxyapatite and calcium apatite based phases were directly formed on Ti6Al4V. ► Hydroxyapatite coatings were characterized systematically for different times. ► After 5 min, hydroxyapatite and calcium based phases begin to form on the coating. ► HAp on the coating is amorphous due to the rapid solidification during PEO. - Abstract: In this study, Ti6Al4V alloy was coated in the solution consisting of calcium acetate (CA) and β-calcium glycerophosphate (β-Ca-GP) by plasma electrolytic oxidation (PEO) to produce hydroxyapatite and calcium apatite-based composite used as of bioactive and biocompatible materials in biomedical applications. The phase structures, surface morphologies, functional groups of molecules, chemical compositions of the surfaces and the binding energies of atoms in the coating were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS), respectively. Anatase, rutile, calcium oxide, titanium phosphide, whitlockite, tri-calcium phosphate (TCP), perovskite calcium titanate and hydroxyapatite phases on the coating were detected by XRD analysis. The surface of coatings produced by PEO method has a porous structure. The amount of amorphous hydroxyapatite is the highest value for the coating produced at 5 min in XPS and ATR-FTIR results, whereas the amount of crystalline hydroxyapatite has the highest value for coating produced at 120 min in XRD results.

Protective coatings for in-vessel fusion devices

International Nuclear Information System (INIS)

Brossa, F.

1984-01-01

Coatings of Al/Si, SAP (Sintered Aluminium Powder), Al 2 O 3 , TiC (low-Z material) and Ta have been developed for in-vessel component protection. Anodic oxidation, vapor depositions, reactive sputtering, chemical vapor deposition (CVD) and plasma spray have been the coating formation methods studied. AISI 316, 310, 304, Inconel 600 and Mo were adopted as base materials. the coatings were characterized in terms of composition, structure and connection with the supporting material. The behavior of coatings under H + , D + and He + irradiation in the energy range 100 eV-8 keV was tested and compared to the solid massive samples. TiC and Ta coatings were tested with thermal shock under power density pulses of 1 kW/cm 2 generated by an electron beam gun. Temperature-dependence of the erosion of TiC by vacuum arcs in a magnetic field was also studied. TiC coatings have low sputtering values, good resistance to arcing and a high chemical stability. TiC and Ta, CVD and plasma spray coatings are thermal-shock resistant. High thermal loads produce cracks but no spalling. Destruction occurred only after melting of the base material. The plasma spray coating method seems to be most appropriate for developing remote handling applications in fusion devices. (orig.)

Carbon coating of simulated nuclear-waste material

International Nuclear Information System (INIS)

Blocher, J.M. Jr.; Browning, M.F.; Kidd, R.W.

1982-03-01

The development of low-temperature pyrolytic carbon (LT-PyC) coatings as described in this report was initiated to reduce the release of volatile waste form components and to permit the coating of larger glass marbles that have low temperature softening points (550 to 600 0 C). Fluidized bed coaters for smaller particles ( 2mm) were used. Coating temperatures were reduced from >1000 0 C for conventional CVD high temperature PyC to approx. 500 0 C by using a catalyst. The coating gas combination that produced the highest quality coatings was found to be Ni(CO) 4 as the catalyst, C 2 H 2 as the carbon source gas, and H 2 as a diluent. Carbon deposition was found to be temperature dependent with a maximum rate observed at 530 0 C. Coating rates were typically 6 to 7 μm/hour. The screw-agitated coater approach to coating large-diameter particles was demonstrated to be feasible. Clearances are important between the auger walls and coater to eliminate binding and attrition. Coatings prepared in fluidized bed coaters using similar parameters are better in quality and are deposited at two to three times the rate as in screw-agitated coaters

Conducting nanofibres produced by electrospinning

Science.gov (United States)

Sen, S.; Davis, F. J.; Mitchell, G. R.; Robinson, E.

2009-08-01

Electrospun fibres based on polypyrrole have been prepared. The incorporation of preformed polypyrrole into fibres electrospun from a carrier polymer can only be achieved when materials are prepared with particulates smaller than the cross-section of the fibre; even so there are some problems, with the substantial loss of material from the electrode tip. As an alternative approach, soluble polypyrroles can be prepared but these are not of sufficient viscosity to prepare electrospun fibres, once again a carrier polymer must be employed. More effective loadings are gained by the process of coating the outer surface of a pre-spun fibre; in this way electrospun fibres coated with polypyrrole can be prepared. This approach has been adapted to produce silver coated polymer fibres by the use of copolymers of styrene and 3-vinyl benzaldehyde.

Conducting nanofibres produced by electrospinning

International Nuclear Information System (INIS)

Sen, S; Mitchell, G R; Robinson, E; Davis, F J

2009-01-01

Electrospun fibres based on polypyrrole have been prepared. The incorporation of preformed polypyrrole into fibres electrospun from a carrier polymer can only be achieved when materials are prepared with particulates smaller than the cross-section of the fibre; even so there are some problems, with the substantial loss of material from the electrode tip. As an alternative approach, soluble polypyrroles can be prepared but these are not of sufficient viscosity to prepare electrospun fibres, once again a carrier polymer must be employed. More effective loadings are gained by the process of coating the outer surface of a pre-spun fibre; in this way electrospun fibres coated with polypyrrole can be prepared. This approach has been adapted to produce silver coated polymer fibres by the use of copolymers of styrene and 3-vinyl benzaldehyde.

Detection and control of as-produced pyrocarbon permeability in biso-coated high-temperature gas-cooled reactor fuel particles

International Nuclear Information System (INIS)

Stinton, D.P.; Thiele, B.A.; Lackey, W.J.; Morgan, C.S.

1980-05-01

About 60 Biso-coated particle batches with coatings deposited in either 0.13- or 0.24-m dia coaters were studied in this work. These batches were carefully characterized for permeability by neon-helium intrusion, long-term chlorination followed by radiography, and fission gas release. These methods of permeability measurement were compared and correlated with deposition conditions as well as pyrocarbon properties. The results from several irradiation tests were also used to evaluate the validity of the permeability measurements. The neon-helium and long-term chlorination techniques correlated very clearly. Coatings with neon-to-helium ratios below 0.3 were gastight by the chlorination procedure, whereas those with ratios above 0.4 were permeable. The fission gas release technique was unable to distinguish between slightly permeable coatings and gastight ones. Therefore, neon-helium and long-term chlorination procedures are preferred over the fission gas release technique. Results from several irradiation tests verified that coatings with neon-to-helium ratios below 0.3 were gastight, whereas those with ratios above about 0.4 were permeable. 10 figures, 2 tables

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.

Novel coating compositions

International Nuclear Information System (INIS)

Kimura, Tadashi; Kobayashi, Juichi; Nakamoto, Hideo.

1969-01-01

An acrylic coating composition rapidly hardenable by irradiating with ionizing radiations or light beams is given using hydroxyl group-containing vinyl monomers, polycarboxylic acid anhydrides, epoxy group-containing vinyl monomers and an organic solvent having a boiling point of at least 120 0 C. The process comprises the steps of first and second reactions. The first reaction takes place between one mol of a hydroxyl group of a basic polymer and at least 0.1 mol of polycarboxylic acid anhydride, wherein the basic polymer has a molecular weight ranging from 5,000 to 100,000 and consists of 1-40% by weight of vinyl monomer containing hydroxyl group, at least 30% of (meth)acrylic monomer and other vinyl monomers if required. The second reaction takes place between one mol of hydroxyl plus a carboxyl group of the thus obtained basic polymer and at least 0.1 mol of an epoxy group-containing vinyl monomer to produce a prepolymer. The prepolymer is mixed with a solvent such as ethyl benzene to produce the coating material. The electron beam accelerator energy level may be 0.1-2.0 MeV. In light beam polymerization, benzoin is particularly utilized as an intensifying substance. In one example, a basic polymer is produced by reacting 39 parts of styrene, 37 parts of ethyl acrylate, 24 parts of 2-hydroxyl ethyl acrylate, 4 parts of dimethyl amino ethyl methacrylate and others. A prepolymer is produced by reacting this basic polymer with 30 parts of glycidyl acrylate and others. (Iwakiri, K.)

Development of intermetallic coatings for fusion power applications

International Nuclear Information System (INIS)

Park, J.H.; Domenico, T.; Dragel, G.; Clark, R.

1994-03-01

In the design of liquid-metal cooling systems, corrosion resistance of structural materials and magnetohydrodynamic (MHD) force and its subsequent influence on thermal hydraulics and corrosion are major concerns. The objective of this study is to develop stable corrosion-resistant electrical insulator coatings at the liquid-metal/structural-material interface, with emphasis on electrically insulating coatings that prevent adverse MHD-generated currents from passing through the structural walls. Vanadium and V-base alloys are potential materials for structural applications in a fusion reactor. Insulator coatings inside the tubing are required when the system is cooled by liquid metals. Various intermetallic films were produced on V, V-t, and V-20 Ti, V-5Cr-t and V-15Cr-t, and Ti, and Types 304 and 316 stainless steel. The intermetallic layers were developed by exposure of the materials to liquid lithium of 3--5 at.% and containing dissolved metallic solutes at temperatures of 416--880 degrees C. Subsequently, electrical insulator coatings were produced by reaction of the reactive layers with dissolved nitrogen in liquid lithium or by air oxidation under controlled conditions at 600--1000 degrees C. These reactions converted the intermetallic layers to electrically insulating oxide/nitride or oxy-nitride layers. This coating method could be applied to a commercial product. The liquid metal can be used over and over because only the solutes are consumed within the liquid metal. The technique can be applied to various shapes because the coating is formed by liquid-phase reaction. This paper will discuss initial results on the nature of the coatings and their in-situ electrical resistivity characteristics in liquid lithium at high temperatures

Bio-inspired citrate functionalized apatite coating on rapid prototyped titanium scaffold

Energy Technology Data Exchange (ETDEWEB)

Yu, Peng [National engineering research center for tissue restoration and reconstruction, South China University of Technology, Guangzhou 510641 (China); Lu, Fang [School of Chinese Materia Medica, Guangzhou University of Chinese Medicine, Guangzhou 510006 (China); Zhu, Wenjun [Department of Prosthodontics, Guanghua School of Stomatology, Guang Dong Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou 510055 (China); Wang, Di [National engineering research center for tissue restoration and reconstruction, South China University of Technology, Guangzhou 510641 (China); Zhu, Xiaojing [Department of Prosthodontics, Guanghua School of Stomatology, Guang Dong Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou 510055 (China); Tan, Guoxin, E-mail: tanguoxin@126.com [Institute of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou 510006 (China); Wang, Xiaolan [National engineering research center for tissue restoration and reconstruction, South China University of Technology, Guangzhou 510641 (China); Zhang, Yu; Li, Lihua [General Hospital of Guangzhou Military Command of PLA, Guangzhou 510010 (China); Ning, Chengyun, E-mail: imcyning@scut.edu.cn [National engineering research center for tissue restoration and reconstruction, South China University of Technology, Guangzhou 510641 (China)

2014-09-15

Highlights: • Designed and reproducible porous titanium scaffolds were produced. • Hydrophilic nanoporous film was built on scaffold. • Apatite coating was deposited on scaffold under the modulation of citrate ions. • Citrate ions could affect CO{sub 3}{sup 2−} incorporation in apatite coatings. - Abstract: Scaffold functionalized with appropriate osteogenic coatings can significantly improve implant-bone response. In this study, with designed model and optimized manufacture parameters, reproducible and precise titanium scaffolds were produced. Reconstructed three-dimensional image and sectional structure of the scaffold were examined by micro-computed tomography and relative software. Alkali treatment was carried out on these manufactured porous scaffolds to produce nanoporous hydrophilic film. After 6 days deposition in simulated body fluid (SBF) containing sodium citrate (SC-SBF), plate-like amorphous calcium phosphate (ACP) coating was deposited on scaffold surface. Ultrasonication tests qualitatively indicated an enhanced adhesion force of apatite coatings deposited in SC-SBF compared to that deposited in SBF. And the effect of citrate ions on the CO{sub 3}{sup 2−} incorporation rate in apatite coating was quantitatively examined by bending vibration of CO{sub 3}{sup 2−} at ∼874 cm{sup −1}. Results indicated the highest carbonate content was obtained at the citrate ion concentration of 6 × 10{sup −5} mol/L in SC-SBF. These three-dimensional porous titanium-apatite hybrid scaffolds are expected to find application in bone tissue regeneration.

Thermally joining and/or coating or thermally separating the workpieces having heat-sensitive coating, comprises restoring coating by thermally coating the coating material after thermally joining and/or coating or thermally separating

OpenAIRE

Riedel, Frank; Winkelmann, Ralf; Puschmann, Markus

2011-01-01

The method for thermally joining and/or coating or thermally separating the workpieces (1), which have a heat-sensitive coating (2), comprises restoring the coating by thermally coating a coating material (3) after thermally joining and/or coating or thermally separating the workpieces. A part of the thermal energy introduced in the workpiece for joining and/or coating or separating or in the workpieces is used for thermally coating the coating material. Two workpieces are welded or soldered ...

The effect of zinc bath temperature on the morphology, texture and corrosion behaviour of industrially produced hot-dip galvanized coatings

Directory of Open Access Journals (Sweden)

A. Bakhtiari

2014-03-01

Full Text Available The purpose of this work is to identify the influence of zinc bath temperature on the morphology, texture and corrosion behavior of hot-dip galvanized coatings. Hot-dip galvanized samples were prepared at temperature in the range of 450-480 °C in steps of 10 °C, which is the conventional galvanizing temperature range in the galvanizing industries. The morphology of coatings was examined with optical microscopy and scanning electron microscopy (SEM. The composition of the coating layers was determined using energy dispersive spectroscopy (EDS analysis. The texture of the coatings was evaluated using X-ray diffraction. Corrosion behavior was performed using salt spray cabinet test and Tafel extrapolation test. From the experimental results, it was found that increasing the zinc bath temperature affects the morphology of the galvanized coatings provoking the appearance of cracks in the coating structure. These cracks prevent formation of a compact structure. In addition, it was concluded that (00.2 basal plane texture component was weakened by increasing the zinc bath temperature and, conversely, appearance of (10.1 prism component, (20.1 high angle pyramidal component and low angle component prevailed. Besides, coatings with strong (00.2 texture component and weaker (20.1 components have better corrosion resistance than the coatings with weak (00.2 and strong (20.1 texture components. Furthermore, corrosion resistance of the galvanized coatings was decreased by increasing the zinc bath temperature.

Carbon nanotube and graphene nanoribbon-coated conductive Kevlar fibers.

Science.gov (United States)

Xiang, Changsheng; Lu, Wei; Zhu, Yu; Sun, Zhengzong; Yan, Zheng; Hwang, Chi-Chau; Tour, James M

2012-01-01

Conductive carbon material-coated Kevlar fibers were fabricated through layer-by-layer spray coating. Polyurethane was used as the interlayer between the Kevlar fiber and carbon materials to bind the carbon materials to the Kevlar fiber. Strongly adhering single-walled carbon nanotube coatings yielded a durable conductivity of 65 S/cm without significant mechanical degradation. In addition, the properties remained stable after bending or water washing cycles. The coated fibers were analyzed using scanning electron microcopy and a knot test. The as-produced fiber had a knot efficiency of 23%, which is more than four times higher than that of carbon fibers. The spray-coating of graphene nanoribbons onto Kevlar fibers was also investigated. These flexible coated-Kevlar fibers have the potential to be used for conductive wires in wearable electronics and battery-heated armors. © 2011 American Chemical Society

Nanostructured Si-substituted hydroxyapatite coatings for biomedical applications

Energy Technology Data Exchange (ETDEWEB)

Rau, Julietta V., E-mail: giulietta.rau@ism.cnr.it [Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche, Via del Fosso del Cavaliere, 100-00133 Rome (Italy); Fosca, Marco [Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche, Via del Fosso del Cavaliere, 100-00133 Rome (Italy); Cacciotti, Ilaria [Università di Roma “Tor Vergata”, Dipartimento di Ingegneria Industriale,UR INSTM “Roma Tor Vergata”, Via del Politecnico, 1-00133 Rome (Italy); Laureti, Sara [Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche, Via Salaria km 29.300-00016 Monterotondo Scalo (RM) (Italy); Bianco, Alessandra [Università di Roma “Tor Vergata”, Dipartimento di Ingegneria Industriale,UR INSTM “Roma Tor Vergata”, Via del Politecnico, 1-00133 Rome (Italy); Teghil, Roberto [Università della Basilicata, Dipartimento di Scienze, Via dell' Ateneo Lucano 10-85100, Potenza (Italy)

2013-09-30

In the present work, the Si-HAp coatings were deposited on titanium substrates by Pulsed Laser Deposition technique. For deposition, the Si-HAp targets (1.4 wt.% of Si), produced starting from wet synthesized powders, were used. The properties of coatings were investigated by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, atomic force microscopy and Vickers microhardness. The obtained Si-HAp coatings presented a nanosized structure, proper thickness and hardness for applications in orthopedical and dental surgery, aimed at improving the stability and the osteointegration of bone implants. - Highlights: ► Pulsed Laser Deposition method was applied to coat heated Titanium supports. ► Films were deposited using a target of Silicon-Hydroxyapatite sintered ceramics. ► Nanostructured crystalline hard film was grown replicating target composition. ► Prepared coating could be used for orthopedic and dental implants applications.

Nanostructured Si-substituted hydroxyapatite coatings for biomedical applications

International Nuclear Information System (INIS)

Rau, Julietta V.; Fosca, Marco; Cacciotti, Ilaria; Laureti, Sara; Bianco, Alessandra; Teghil, Roberto

2013-01-01

In the present work, the Si-HAp coatings were deposited on titanium substrates by Pulsed Laser Deposition technique. For deposition, the Si-HAp targets (1.4 wt.% of Si), produced starting from wet synthesized powders, were used. The properties of coatings were investigated by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, atomic force microscopy and Vickers microhardness. The obtained Si-HAp coatings presented a nanosized structure, proper thickness and hardness for applications in orthopedical and dental surgery, aimed at improving the stability and the osteointegration of bone implants. - Highlights: ► Pulsed Laser Deposition method was applied to coat heated Titanium supports. ► Films were deposited using a target of Silicon-Hydroxyapatite sintered ceramics. ► Nanostructured crystalline hard film was grown replicating target composition. ► Prepared coating could be used for orthopedic and dental implants applications

SiO{sub 2} coating of silver nanoparticles by photoinduced chemical vapor deposition

Energy Technology Data Exchange (ETDEWEB)

Boies, Adam M; Girshick, Steven L [Department of Mechanical Engineering, University of Minnesota, 111 Church Street SE, Minneapolis, MN 55455 (United States); Roberts, Jeffrey T [Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, MN 55455 (United States); Zhang Bin; Nakamura, Toshitaka; Mochizuki, Amane, E-mail: jtrob@umn.ed, E-mail: slg@umn.ed [Nitto Denko Technical Corporation, 501 Via Del Monte, Oceanside, CA 92058 (United States)

2009-07-22

Gas-phase silver nanoparticles were coated with silicon dioxide (SiO{sub 2}) by photoinduced chemical vapor deposition (photo-CVD). Silver nanoparticles, produced by inert gas condensation, and a SiO{sub 2} precursor, tetraethylorthosilicate (TEOS), were exposed to vacuum ultraviolet (VUV) radiation at atmospheric pressure and varying temperatures. The VUV photons dissociate the TEOS precursor, initiating a chemical reaction that forms SiO{sub 2} coatings on the particle surfaces. Coating thicknesses were measured for a variety of operation parameters using tandem differential mobility analysis and transmission electron microscopy. The chemical composition of the particle coatings was analyzed using energy dispersive x-ray spectrometry and Fourier transform infrared spectroscopy. The highest purity films were produced at 300-400 {sup 0}C with low flow rates of additional oxygen. The photo-CVD coating technique was shown to effectively coat nanoparticles and limit core particle agglomeration at concentrations up to 10{sup 7} particles cm{sup -3}.

Development of tungsten coatings for the corrosion protection of alumina-based ceramics

International Nuclear Information System (INIS)

Arons, R.M.; Dusek, J.T.; Hafstrom, J.W.

1979-01-01

A means of applying tungsten coatings to an alumina based ceramic is described. A slurry of pure tungsten was prepared and applied by brush coating or slip casting on the alumina-3 wt % Yt small crucible. The composite was fired and a very dense ceramic crucible with a crack free tungsten coating was produced

TiO{sub 2} coated multi-wall carbon nanotube as a corrosion inhibitor for improving the corrosion resistance of BTESPT coatings

Energy Technology Data Exchange (ETDEWEB)

Zhang, Yuping; Zhu, Hongzheng; Zhuang, Chen [Institute of Materials Science and Engineering, Ocean University of China, Songling Road 238, Qingdao, 266100 (China); Chen, Shougang, E-mail: sgchen@ouc.edu.cn [Institute of Materials Science and Engineering, Ocean University of China, Songling Road 238, Qingdao, 266100 (China); Wang, Longqiang [Institute of Materials Science and Engineering, Ocean University of China, Songling Road 238, Qingdao, 266100 (China); Dong, Lihua [Institute of Ocean Materials and Engineering, Shanghai Maritime University, Shanghai, 200135 (China); Yin, Yansheng, E-mail: ysyin@shmtu.edu.cn [Institute of Ocean Materials and Engineering, Shanghai Maritime University, Shanghai, 200135 (China)

2016-08-15

The composite coatings of TiO{sub 2} coated multi-wall carbon nanotube (MWCNTs)/bis-[triethoxysilylpropyl]tetrasulfide (BTESPT) with different components were prepared on AA 2024 by the cathodic electrophoretic deposition technique and the experimental conditions were optimized to attain the appropriate volume ratio. The modified MWCNTs obviously improved the corrosion resistance of BTESPT and BTESPT/TiO{sub 2} coatings, especially for the long-term corrosion resistance ability because of the good dispersion of MWCNTs. The geometry of composite coatings were explored by scanning electron microscopy, fourier transform infrared spectra and the surface coverage rate (θ), the results indicate that the composite coatings produce good cross-linked structure at the interfacial layer, the coating compactness increases gradually with the addition of TiO{sub 2} and/or MWCNTs, and the composite coating effectively postpones the production of cracks with the addition of MWCNTs. - Highlights: • The composite coatings with different components were prepared on AA 2024 by the cathodic electrophoretic deposition technology. • The formation of composite coating on AA 2024 surface considerably improved the corrosion resistance ability. • The composite coating with a TiO{sub 2} to MWCNTs volume ratio of 4/1 shows the best corrosion resistance. • The kinetic evaluation of inhibitive behavior for different coatings against immersion time was explored.

Hybrid Perovskite Thin Film Formation: From Lab Scale Spin Coating to Large Area Blade Coating

KAUST Repository

Munir, Rahim

2017-01-01

in which an anti-solvent is used during the coating process through the solvent mixture of GBL and DMSO in different ratios. It has been shown that solvent engineering produce pin hole-free films, justifying its wide adoption across the field. We

Thick metallic coatings produced by coaxial and side laser cladding : Processing and properties

NARCIS (Netherlands)

Ocelík, V.; De Hosson, J.T.M.

2010-01-01

Cobalt and iron-based, defect-free coatings with thicknesses from 1 to 3.3. mm were created by a laser cladding process on different steel substrates. Extensive laser cladding experiments with a gradual change of laser power were used to study relations between main processing parameters and

Corrosion protection of SiC-based ceramics with CVDMullite coatings

Energy Technology Data Exchange (ETDEWEB)

Sarin, V.; Auger, M. [Boston Univ., MA (United States)

1997-05-01

Silicon carbide ceramics are the leading candidate materials for use as heat exchangers in advanced combined cycle power plants because of their unique combination of high temperature strength, high thermal conductivity, excellent thermal shock resistance, and good high temperature stability and oxidation resistance. Ceramic coatings are being considered for diesel engine cylinder liners, piston caps, valve faces and seats, piston rings, and for turbine components such as combustors, blades, stators, seals, and bearings. Under such conditions ceramics are better suited to high temperature environments than metals. For the first time, adherent crystalline mullite coatings have been chemically vapor deposited onto SiC substrates to enhance its corrosion/oxidation resistance. Thermodynamic and kinetic considerations have been utilized to produce mullite coatings with a variety of growth rates, compositions, and morphologies. The flexibility of processing can be exploited to produce coated ceramics with properties tailored to specific applications and varied corrosive environments. These corrosive environments include thermal, Na{sub 2}SO{sub 4}, O{sub 2} and coal slag.

Thick CrN/NbN multilayer coating deposited by cathodic arc technique

Energy Technology Data Exchange (ETDEWEB)

Araujo, Juliano Avelar; Tschiptschin, Andre Paulo; Souza, Roberto Martins, E-mail: antschip@usp.br [Universidade de Sao Paulo (USP), SP (Brazil); Lima, Nelson Batista de [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2017-01-15

The production of tribological nanoscale multilayer CrN/NbN coatings up to 6 μm thick by Sputtering/HIPIMS has been reported in literature. However, high demanding applications, such as internal combustion engine parts, need thicker coatings (>30 μm). The production of such parts by sputtering would be economically restrictive due to low deposition rates. In this work, nanoscale multilayer CrN/NbN coatings were produced in a high-deposition rate, industrial-size, Cathodic Arc Physical Vapor Deposition (ARC-PVD) chamber, containing three cathodes in alternate positions (Cr/ Nb/Cr). Four 30 μm thick NbN/CrN multilayer coatings with different periodicities (20, 10, 7.5 and 4 nm) were produced. The coatings were characterized by X-Ray Diffraction (XRD) and Transmission Electron Microscopy (TEM). The multilayer coating system was composed of alternate cubic rock salt CrN and NbN layers, coherently strained due to lattice mismatch. The film grew with columnar morphology through the entire stratified structure. The periodicities adopted were maintained throughout the entire coating. The 20 nm periodicity coating showed separate NbN and CrN peaks in the XRD patterns, while for the lower periodicity (≤10nm) coatings, just one intermediate lattice (d-spacing) was detected. An almost linear increase of hardness with decreasing bilayer period indicates that interfacial effects can dominate the hardening mechanisms. (author)

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....

Laser Cladding of Composite Bioceramic Coatings on Titanium Alloy

Science.gov (United States)

Xu, Xiang; Han, Jiege; Wang, Chunming; Huang, Anguo

2016-02-01

In this study, silicon nitride (Si3N4) and calcium phosphate tribasic (TCP) composite bioceramic coatings were fabricated on a Ti6Al4V (TC4) alloy using Nd:YAG pulsed laser, CO2 CW laser, and Semiconductor CW laser. The surface morphology, cross-sectional microstructure, mechanical properties, and biological behavior were carefully investigated. These investigations were conducted employing scanning electron microscope, energy-dispersive x-ray spectroscopy, and other methodologies. The results showed that both Si3N4 and Si3N4/TCP composite coatings were able to form a compact bonding interface between the coating and the substrate by using appropriate laser parameters. The coating layers were dense, demonstrating a good surface appearance. The bioceramic coatings produced by laser cladding have good mechanical properties. Compared with that of the bulk material, microhardness of composite ceramic coatings on the surface significantly increased. In addition, good biological activity could be obtained by adding TCP into the composite coating.

The fabrication and characterization of replicated and lacquer coated grazing

International Nuclear Information System (INIS)

Ulmer, M.P.; Haidle, R.; Altkorn, R.; Georgeopolos, P.; Rodricks, B.; Takacs, P.Z.

1992-01-01

This paper reports on work done over the past two years in our laboratory to produce X-ray optics. We also report on tests that we have made to evaluate the performance of pieces that we have produced. As we progress towards the 21st century, there is a growing need to understand fabrication techniques for grazing incidence optics. To this end we report our results of fabricating, testing, and measuring both Wolter I optics and flats. We have used the techniques of lacquer coating. We have made flats to determine our ability to coat surfaces with lacquer and gold, as well as to demonstrate reflectivity up to 40 keV. We also produced Wolter I optics nickel optics with a gold coated optical surface. Here we report and interpret results from X-ray reflectivity and Wyko profiler optical measurements. We also describe our fabrication process and provide a critique of the process and describe how we hope to further improve upon the basic technique

Boron nitride nanosheets as oxygen-atom corrosion protective coatings

International Nuclear Information System (INIS)

Yi, Min; Shen, Zhigang; Zhao, Xiaohu; Liang, Shuaishuai; Liu, Lei

2014-01-01

The research of two-dimensional nanomaterials for anticorrosion applications is just recently burgeoning. Herein, we demonstrate the boron nitride nanosheets (BNNSs) coatings for protecting polymer from oxygen-atom corrosion. High-quality BNNSs, which are produced by an effective fluid dynamics method with multiple exfoliation mechanisms, can be assembled into coatings with controlled thickness by vacuum filtration. After exposed in atom oxygen, the naked polymer is severely corroded with remarkable mass loss, while the BNNSs-coated polymer remains intact. Barrier and bonding effects of the BNNSs are responsible for the coating's protective performance. These preliminary yet reproducible results pave a way for resisting oxygen-atom corrosion

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.

Corrosion resistance of CrN thin films produced by dc magnetron sputtering

Energy Technology Data Exchange (ETDEWEB)

Ruden, A. [Laboratorio de Física del Plasma, Universidad Nacional de Colombia Sede Manizales, Km. 9 vía al Magdalena, Manizales (Colombia); Laboratorio de Recubrimientos Duros y Aplicaciones Industriales–RDAI, Universidad del Valle, Calle 13 N° 100-00 Ciudadela Meléndez, Cali (Colombia); Departamento de matemáticas, Universidad Tecnológica de Pereira, Pereira (Colombia); Restrepo-Parra, E., E-mail: erestrepopa@unal.edu.co [Laboratorio de Física del Plasma, Universidad Nacional de Colombia Sede Manizales, Km. 9 vía al Magdalena, Manizales (Colombia); Paladines, A.U.; Sequeda, F. [Laboratorio de Recubrimientos Duros y Aplicaciones Industriales–RDAI, Universidad del Valle, Calle 13 N° 100-00 Ciudadela Meléndez, Cali (Colombia)

2013-04-01

In this study, the electrochemical behavior of chromium nitride (CrN) coatings deposited on two steel substrates, AISI 304 and AISI 1440, was investigated. The CrN coatings were prepared using a reactive d.c. magnetron sputtering deposition technique at two different pressures (P1 = 0.4 Pa and P2 = 4 Pa) with a mixture of N{sub 2}–Ar (1.5-10). The microstructure and crystallinity of the CrN coatings were investigated using X-ray diffraction. The aqueous corrosion behavior of the coatings was evaluated using two methods. The polarization resistance (Tafel curves) and electrochemical impedance spectra (EIS) in a saline (3.5% NaCl solution) environment were measured in terms of the open-circuit potentials and polarization resistance (R{sub p}). The results indicated that the CrN coatings present better corrosion resistance and R{sub p} values than do the uncoated steel substrates, especially for the coatings produced on the AISI 304 substrates, which exhibited a strong enhancement in the corrosion resistance. Furthermore, better behavior was observed for the coatings produced at lower pressures (0.4 Pa) than those grown at 4 Pa.

Electrophoretic Deposition as a New Bioactive Glass Coating Process for Orthodontic Stainless Steel

Directory of Open Access Journals (Sweden)

Kyotaro Kawaguchi

2017-11-01

Full Text Available This study investigated the surface modification of orthodontic stainless steel using electrophoretic deposition (EPD of bioactive glass (BG. The BG coatings were characterized by spectrophotometry, scanning electron microscopy with energy dispersive X-ray spectrometry, and X-ray diffraction. The frictional properties were investigated using a progressive load scratch test. The remineralization ability of the etched dental enamel was studied according to the time-dependent mechanical properties of the enamel using a nano-indentation test. The EPD process using alternating current produced higher values in both reflectance and lightness. Additionally, the BG coating was thinner than that prepared using direct current, and was completely amorphous. All of the BG coatings displayed good interfacial adhesion, and Si and O were the major components. Most BG-coated specimens produced slightly higher frictional forces compared with non-coated specimens. The hardness and elastic modulus of etched enamel specimens immersed with most BG-coated specimens recovered significantly with increasing immersion time compared with the non-coated specimen, and significant acid-neutralization was observed for the BG-coated specimens. The surface modification technique using EPD and BG coating on orthodontic stainless steel may assist the development of new non-cytotoxic orthodontic metallic appliances having satisfactory appearance and remineralization ability.

The Bioactivity and Photocatalytic Properties of Titania Nanotube Coatings Produced with the Use of the Low-Potential Anodization of Ti6Al4V Alloy Surface

Science.gov (United States)

Radtke, Aleksandra; Kozak, Wiesław; Sadowska, Beata; Więckowska-Szakiel, Marzena; Szubka, Magdalena; Talik, Ewa; Pleth Nielsen, Lars; Piszczek, Piotr

2017-01-01

Titania nanotube (TNT) coatings were produced using low-potential anodic oxidation of Ti6Al4V substrates in the potential range 3–20 V. They were analysed by X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). The wettability was estimated by measuring the contact angle when applying water droplets. The bioactivity of the TNT coatings was established on the basis of the biointegration assay (L929 murine fibroblasts adhesion and proliferation) and antibacterial tests against Staphylococcus aureus (ATCC 29213). The photocatalytic efficiency of the TNT films was studied by the degradation of methylene blue under UV irradiation. Among the studied coatings, the TiO2 nanotubes obtained with the use of 5 V potential (TNT5) were found to be the most appropriate for medical applications. The TNT5 sample possessed antibiofilm properties without enriching it by additional antimicrobial agent. Furthermore, it was characterized by optimal biocompatibility, performing better than pure Ti6Al4V alloy. Moreover, the same sample was the most photocatalytically active and exhibited the potential for the sterilization of implants with the use of UV light and for other environmental applications. PMID:28933732

The Bioactivity and Photocatalytic Properties of Titania Nanotube Coatings Produced with the Use of the Low-Potential Anodization of Ti6Al4V Alloy Surface.

Science.gov (United States)

Radtke, Aleksandra; Topolski, Adrian; Jędrzejewski, Tomasz; Kozak, Wiesław; Sadowska, Beata; Więckowska-Szakiel, Marzena; Szubka, Magdalena; Talik, Ewa; Pleth Nielsen, Lars; Piszczek, Piotr

2017-07-26

Titania nanotube (TNT) coatings were produced using low-potential anodic oxidation of Ti6Al4V substrates in the potential range 3-20 V. They were analysed by X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). The wettability was estimated by measuring the contact angle when applying water droplets. The bioactivity of the TNT coatings was established on the basis of the biointegration assay (L929 murine fibroblasts adhesion and proliferation) and antibacterial tests against Staphylococcus aureus (ATCC 29213). The photocatalytic efficiency of the TNT films was studied by the degradation of methylene blue under UV irradiation. Among the studied coatings, the TiO₂ nanotubes obtained with the use of 5 V potential (TNT5) were found to be the most appropriate for medical applications. The TNT5 sample possessed antibiofilm properties without enriching it by additional antimicrobial agent. Furthermore, it was characterized by optimal biocompatibility, performing better than pure Ti6Al4V alloy. Moreover, the same sample was the most photocatalytically active and exhibited the potential for the sterilization of implants with the use of UV light and for other environmental applications.

Electron beam irradiating process for rendering rough or topographically irregular surface substrates smooth; and coated substrates produced thereby

International Nuclear Information System (INIS)

Nablo, S.V.

1979-01-01

This disclosure involves a novel process for instantaneous electron-beam curing of very thin low viscosity, solventless coating upon rough, irregular or textured surfaces of a substrate such as paper or the like. Through rather critical timing and energy adjustment procedures, the coating firmly adheres to the surface before the coating can conform to the roughness or texture contour or substantially penetrate into the surface. By this method a solidified very smooth outer surface is provided for the substrate that is particularly used for metalization and other finished layerings. (author)

Measurement of Turbulent Skin Friction Drag Coefficients Produced by Distributed Surface Roughness of Pristine Marine Coatings

DEFF Research Database (Denmark)

Zafiryadis, Frederik; Meyer, Knud Erik; Gökhan Ergin, F.

drag coefficients as well as roughness Reynolds numbers for the various marine coatings across the range of Rex by fitting of the van Driest profile. The results demonstrate sound agreement with the present ITTC method for determining skin friction coefficients for practically smooth surfaces at low...... Reynolds numbers compared to normal operation mode for the antifouling coatings. Thus, better estimates for skin friction of rough hulls can be realised using the proposed method to optimise preliminary vessel design....

Genetics of seed coat color in sesame ( Sesamum indicum L ...

African Journals Online (AJOL)

Seed coat colour of sesame is commercially an important trait. Developing white seeded varieties with long lasting luster has received momentous attention in most of the major sesame producing countries including India. The present investigation centered on the genetic control of seed coat colour in sesame. No genetic ...

Improvement in Microstructure Performance of the NiCrBSi Reinforced Coating on TA15 Titanium Alloy

Science.gov (United States)

Peng, Li

2012-10-01

This work is based on the dry sliding wear of NiCrBSi reinforced coating deposited on TA15 titanium alloy using the laser cladding technique, the parameters of which were such as to provide almost crack-free coatings with minimum dilution and very low porosity. SEM results indicated that a laser clad coating with metallurgical joint to the substrate was formed. Compared with TA15 substrate, an improvement of the micro-hardness and wear resistance was observed for this composite coating. Rare earth oxide Y2O3 was beneficial in producing of the amorphous phases in laser clad coating. With addition of Y2O3, more amorphous alloys were produced, which increased the micro-hardness and wear resistance of the coating.

Preparation of Ti-coated diamond particles by microwave heating

International Nuclear Information System (INIS)

Gu, Quanchao; Peng, Jinghui; Xu, Lei; Srinivasakannan, C.

2016-01-01

Highlights: • The Ti-Coated diamond particles have been prepared using by microwave heating. • The uniform and dense coating can be produced, and the TiC species was formed. • With increases the temperature results in the thickness of coating increased. • The coating/diamond interfacial bonding strength increased with temperature increasing until 760 °C, then decreased. - Abstract: Depositing strong carbide-forming elements on diamond surface can dramatically improve the interfacial bonding strength between diamond grits and metal matrix. In the present work, investigation on the preparation of Ti-coated diamond particles by microwave heating has been conducted. The morphology, microstructure, and the chemical composition of Ti-coated diamond particles were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy dispersive x-ray spectrometer (EDX). The thickness of Ti coating was measured and the interfacial binding strength between Ti coating and diamond was analyzed. The results show that the surface of the diamond particles could be successfully coated with Ti, forming a uniform and continuous Ti-coated layer. The TiC was found to form between the surface of diamond particles and Ti-coated layer. The amount of TiC as well as the thickness of coating increased with increasing coating temperature, furthermore, the grain size of the coating also grew gradually. The interfacial bonding strength between coating and diamond was found to be best at the temperature of 760 °C.

Preparation of Ti-coated diamond particles by microwave heating

Energy Technology Data Exchange (ETDEWEB)

Gu, Quanchao [National Local Joint Laboratory of Engineering Application of Microwave Energy and Equipment Technology, Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093 (China); Yunnan Copper Smelting and Processing Complex, Yunnan Copper (Group) CO., LTD., Kunming 650102 (China); International Joint Research Center of Advanced Preparation of Superhard Materials Field, Kunming Academician Workstation of Advanced Preparation of Superhard Materials Field, Kunming 650093 (China); Peng, Jinghui [National Local Joint Laboratory of Engineering Application of Microwave Energy and Equipment Technology, Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093 (China); International Joint Research Center of Advanced Preparation of Superhard Materials Field, Kunming Academician Workstation of Advanced Preparation of Superhard Materials Field, Kunming 650093 (China); Xu, Lei, E-mail: xulei_kmust@aliyun.com [National Local Joint Laboratory of Engineering Application of Microwave Energy and Equipment Technology, Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093 (China); Mechanical Engineering, University of Washington, Seattle, WA 98195 (United States); International Joint Research Center of Advanced Preparation of Superhard Materials Field, Kunming Academician Workstation of Advanced Preparation of Superhard Materials Field, Kunming 650093 (China); Srinivasakannan, C. [Chemical Engineering Department, The Petroleum Institute, P.O. Box 2533, Abu Dhabi (United Arab Emirates); and others

2016-12-30

Highlights: • The Ti-Coated diamond particles have been prepared using by microwave heating. • The uniform and dense coating can be produced, and the TiC species was formed. • With increases the temperature results in the thickness of coating increased. • The coating/diamond interfacial bonding strength increased with temperature increasing until 760 °C, then decreased. - Abstract: Depositing strong carbide-forming elements on diamond surface can dramatically improve the interfacial bonding strength between diamond grits and metal matrix. In the present work, investigation on the preparation of Ti-coated diamond particles by microwave heating has been conducted. The morphology, microstructure, and the chemical composition of Ti-coated diamond particles were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy dispersive x-ray spectrometer (EDX). The thickness of Ti coating was measured and the interfacial binding strength between Ti coating and diamond was analyzed. The results show that the surface of the diamond particles could be successfully coated with Ti, forming a uniform and continuous Ti-coated layer. The TiC was found to form between the surface of diamond particles and Ti-coated layer. The amount of TiC as well as the thickness of coating increased with increasing coating temperature, furthermore, the grain size of the coating also grew gradually. The interfacial bonding strength between coating and diamond was found to be best at the temperature of 760 °C.

FABRICATION OF NANOPOROUS Ni VIA DEALLOYING OF ZINC-NICKEL COATINGS

OpenAIRE

Seda , Oturak

2015-01-01

Dealloying is a selective leaching of one component in a multicomponent alloy so as to produce a nanoporous structure. In this study, it was aimed to produce nanoporous Ni coating by selective leaching of Zn in a Zn-Ni alloy. To achieve this, first the Zn-Ni alloy was obtained by electrodeposition in a bath containing Zn and Ni salts. Then, dealloying was performed at different concentrations of NaOH solution. Dealloying led to crack formation in the coatings which thus prevented the formatio...

Interfacial Coatings for Inorganic Composite Insulation Systems

International Nuclear Information System (INIS)

Hooker, M. W.; Fabian, P. E.; Stewart, M. W.; Grandlienard, S. D.; Kano, K. S.

2006-01-01

Inorganic (ceramic) insulation materials are known to have good radiation resistance and desirable electrical and mechanical properties at cryogenic and elevated temperatures. In addition, ceramic materials can withstand the high-temperature reaction cycle used with Nb3Sn superconductor materials, allowing the insulation to be co-processed with the superconductor in a wind-and-react fabrication process. A critical aspect in the manufacture of ceramic-based insulation systems is the deposition of suitable fiber-coating materials that prevent chemical reaction of the fiber and matrix materials, and thus provide a compliant interface between the fiber and matrix, which minimizes the impact of brittle failure of the ceramic matrix. Ceramic insulation produced with CTD-FI-202 fiber interfaces have been found to exhibit very high shear and compressive strengths. However, this material is costly to produce. Thus, the goal of the present work is to evaluate alternative, lower-cost materials and processes. A variety of oxide and polyimide coatings were evaluated, and one commercially available polyimide coating has been shown to provide some improvement as compared to uncoated and de-sized S2 glass

Antireflection coatings with Chebyshev or Butterworth response - Design

Science.gov (United States)

Baumeister, Philip

1986-12-01

The approximation of Kard (1971) is used to find values for the refractive indices of nonabsorbing layers with equal optical thickness to produce an antireflection (AR) coating for a dielectric substrate that has a Chebyshev spectral response, with application to the design of bandpass filters. The method is numerically demonstrated with the example of four-layer Chebyshev AR coatings with narrow, medium and wide bandwidths, and substrates of indices 2, 5, and 10. Approximate indices are also given for the case when the radiant reflectance/transmittance of the coating vs frequency is maximally flat (Butterworth response).

Tribological properties of B{sub 4}C-TiB{sub 2}-TiC-Ni cermet coating produced by HVOF

Energy Technology Data Exchange (ETDEWEB)

Rafiei, Mahdi [Islamic Azad Univ., Najafabad (Iran, Islamic Republic of). Dept. of Materials Engineering; Isfahan Univ. of Technology, Isfahan (Iran, Islamic Republic of). Depr. of Materials Engineering; Shamanian, Morteza; Salehi, Mehdi [Isfahan Univ. of Technology, Isfahan (Iran, Islamic Republic of). Depr. of Materials Engineering; Mostaan, Hossein [Arak Univ., Arak (Iran, Islamic Republic of). Dept. of Materials and Metallurgical Engineering

2017-08-15

In this study, B{sub 4}C-TiB{sub 2}-TiC-Ni coating was sprayed on the surface of 4130 steel by high velocity oxy-fuel torch. The tribological behavior of samples was studied by ball on disk wear testing. Structural evolution of the coating was analyzed by X-ray diffractometry. The microstructure of the coating, wear track and Al{sub 2}O{sub 3} ball was investigated by scanning electron microscopy, field emission scanning electron microscopy and optical microscopy. Elemental analysis of the wear track was done by energy dispersive X-ray spectroscopy. It was found that a cermet coating containing B{sub 4}C, TiB{sub 2}, TiC and Ni phases with good bonding to the 4130 steel substrate with no sign of any cracking or pores was formed. The wear mechanism of the composite coating was delamination. The friction coefficient of samples was decreased with increasing load because of higher frictional heat and creation of more oxide islands.

Effect of Coating Thickness on the Properties of TiN Coatings Deposited on Tool Steels Using Cathodic Arc Pvd Technique

Science.gov (United States)

Mubarak, A.; Akhter, Parvez; Hamzah, Esah; Mohd Toff, Mohd Radzi Hj.; Qazi, Ishtiaq A.

Titanium nitride (TiN) widely used as hard coating material, was coated on tool steels, namely on high-speed steel (HSS) and D2 tool steel by physical vapor deposition method. The study concentrated on cathodic arc physical vapor deposition (CAPVD), a technique used for the deposition of hard coatings for tooling applications, and which has many advantages. The main drawback of this technique, however, is the formation of macrodroplets (MDs) during deposition, resulting in films with rougher morphology. Various standard characterization techniques and equipment, such as electron microscopy, atomic force microscopy, hardness testing machine, scratch tester, and pin-on-disc machine, were used to analyze and quantify the following properties and parameters: surface morphology, thickness, hardness, adhesion, and coefficient of friction (COF) of the deposited coatings. Surface morphology revealed that the MDs produced during the etching stage, protruded through the TiN film, resulting in film with deteriorated surface features. Both coating thickness and indentation loads influenced the hardness of the deposited coatings. The coatings deposited on HSS exhibit better adhesion compared to those on D2 tool steel. Standard deviation indicates that the coating deposited with thickness around 6.7 μm showed the most stable trend of COF versus sliding distance.

Optimization and characterization of adhesion properties of DLC coatings on different substrates

International Nuclear Information System (INIS)

Waseem, B; Alam, S; Irfan, M; Shahid, M; Soomro, B D; Hashim, S; Iqbal, R

2014-01-01

The Diamond Like Carbon coatings (DLC) are gaining prime importance in the field of surface engineering especially cutting tools technology. The self lubricating property of these coatings makes them unique among other coatings like TiN, TiAlN, CrN etc. Unlike other coatings, DLC coatings give better surface finish and their self lubrication reduces the wear of a part to large extent. In present work, different substrates were selected to study the wear and adhesion behavior of DLC coatings. The coating was produced by physical Vapor Deposition (PVD) technique and the adhesive properties of DLC coatings were analyzed under ambient conditions using nano Scratch testing. Scanning electron microscope (SEM) was used to observe the scratches and their mechanisms

Optimization and characterization of adhesion properties of DLC coatings on different substrates

International Nuclear Information System (INIS)

Waseem, B.; Alam, S.; Irfan, M.; Shahid, M.; Soomro, B. D.; Hashim, S.; Iqbal, R.

2013-01-01

The Diamond Like Carbon coatings (DLC) are gaining prime importance in the field of surface engineering especially cutting tools technology. The self lubricating property of these coatings makes them unique among other coatings like TiN, TiAlN, CrN etc. Unlike other coatings, DLC coatings give better surface finish and their self lubrication reduces the wear of a part to large extent. In present work, different substrates were selected to study the wear and adhesion behavior of DLC coatings. The coating was produced by physical Vapor Deposition (PVD) technique and the adhesive properties of DLC coatings were analyzed under ambient conditions using nano Scratch testing. Scanning electron microscope (SEM) was used to observe the scratches and their mechanisms. (author)

Development of durable self-cleaning coatings using organic–inorganic hybrid sol–gel method

Energy Technology Data Exchange (ETDEWEB)

Kumar, Divya [School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Wu, Xinghua [School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Energy Research Institute at NTU - ERI@N, 1 CleanTech Loop, #06-04, CleanTech One, Singapore 637141 (Singapore); Fu, Qitao [School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Ho, Jeffrey Weng Chye [School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Energy Research Institute at NTU - ERI@N, 1 CleanTech Loop, #06-04, CleanTech One, Singapore 637141 (Singapore); Kanhere, Pushkar D. [Energy Research Institute at NTU - ERI@N, 1 CleanTech Loop, #06-04, CleanTech One, Singapore 637141 (Singapore); Li, Lin [School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Chen, Zhong, E-mail: ASZChen@ntu.edu.sg [School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Energy Research Institute at NTU - ERI@N, 1 CleanTech Loop, #06-04, CleanTech One, Singapore 637141 (Singapore)

2015-07-30

Highlights: • A facile method to produce sol–gel based self-cleaning coatings is described. • Effect of filler size and content is evaluated via contact angle, sliding angle, and surface morphology. • Coating with 15 wt.% nano-sized silica fillers exhibits the best self-cleaning performance. • The coatings are resistant to UV radiation and retain the functionality after the abrasion test. • A self-cleaning test and scheme to quantify the self-cleaning efficiency are described in this work. - Abstract: Self-cleaning coatings with excellent water-repellence and good mechanical properties are in high demand. However, producing such coatings with resistance to mechanical abrasion and environmental weathering remains a key challenge. Mechanically robust coatings based on tetraethylorthosilicate (TEOS) and glycidoxypropyltriethoxysilane (Glymo) have been prepared using a sol–gel method. Emphasis is given to the addition of Glymo, an epoxy silane which creates an organic matrix that blends with the inorganic Si−O−Si matrix formed from the TEOS. The combination of the blended matrix produced coatings with good adhesion to substrates and improved mechanical properties. Fluoroalkylsilane (FAS) and silica fillers were introduced to increase the hydrophobicity of the coating. It was found that the water contact angle (CA) of these coatings increases from 115° to 164° upon decreasing filler size from 1–5 μm to 10–20 nm. The sliding angle (SA) for coatings with 15 wt.% loading of 10–20 nm silica is around 2°. UV weathering does not show significant effect on the properties of the coatings. Mechanical properties and performances including hardness, Young's modulus, coating adhesion and abrasion resistance were systematically analyzed. In the current work, a simple self-cleaning test, which measures the extent of dirt accumulation and subsequent removal by water spray, was performed. The coatings with 15 wt.% loading of 10–20 nm silica particles

Development and characterization of nano structured hard coatings for high performance tools by using PVD technique

International Nuclear Information System (INIS)

Irfan, M.; Alam, S.; Hassan, Z.; Iftikhar, F.; Khadim, S.

2006-01-01

No doubt hard coatings nave major applications in high performance cutting tools in order to improve tribological and mechanical properties of these tools since last years. The actual top development in this regard is the development of PVD based AlTiN coatings and their supplementation with nano. layers. In present these nano coatings are replaced by nano composites along with an additional development of Multilayer Nano structured coatings. This PVD based nano structured coating development optimized by process parameters, crystalline structure and deposition in multilayer. These coating are definitely produced by combination of ARC and Sputtering with filtration of arc droplets. It is studied that the properties like oxidation resistance, wear resistance and resistance against chemical reaction may be obtained by alloying additions of different elements. This paper presents different development stages and Process parameters for- producing high performance Nanostructure coatings and including adhesion test by using Kalomax system for determination of adhesion strength of these coatings and coating thickness measurements by using image analyzer system. Results and conclusions are showing the optimum values for better coatings for different applications. (author)

Computational homogenisation for thermoviscoplasticity: application to thermally sprayed coatings

Science.gov (United States)

Berthelsen, Rolf; Denzer, Ralf; Oppermann, Philip; Menzel, Andreas

2017-11-01

Metal forming processes require wear-resistant tool surfaces in order to ensure a long life cycle of the expensive tools together with a constant high quality of the produced components. Thermal spraying is a relatively widely applied coating technique for the deposit of wear protection coatings. During these coating processes, heterogeneous coatings are deployed at high temperatures followed by quenching where residual stresses occur which strongly influence the performance of the coated tools. The objective of this article is to discuss and apply a thermo-mechanically coupled simulation framework which captures the heterogeneity of the deposited coating material. Therefore, a two-scale finite element framework for the solution of nonlinear thermo-mechanically coupled problems is elaborated and applied to the simulation of thermoviscoplastic material behaviour including nonlinear thermal softening in a geometrically linearised setting. The finite element framework and material model is demonstrated by means of numerical examples.

Powder ink coatings in nuclear medicine and nuclear technology

International Nuclear Information System (INIS)

Kunze, S.; Schlautek, H.

1996-01-01

Powder ink coatings are being used more and more frequently to protect the surfaces of movable objects of metal, such as machines, equipment, furniture, shelves, because this solvent-free coating technique, which produces almost no residues, helps to keep the environment clean. The white and grey baking coatings so far tested for decontaminability are presented in the article. Powder ink coatings of different shades and with different binders were tested for their ability to meet future standards. All systems under examination demonstrated excellent decontaminability before and after gamma exposure to 0.3 MGy. The same performance was obtained also after exposure to 3 MGy (ten times the level required for coatings in nuclear installations according to DIN 55991 Part 1), with the exception of one polyester metallic coating. After having been exposed to chemicals and decontamination solutions, all specimens showed only permissible discoloration. (orig.) [de

Electrically Conductive and Protective Coating for Planar SOFC Stacks

Energy Technology Data Exchange (ETDEWEB)

Choi, Jung-Pyung; Stevenson, Jeffry W.

2017-12-04

Ferritic stainless steels are preferred interconnect materials for intermediate temperature SOFCs because of their resistance to oxidation, high formability and low cost. However, their protective oxide layer produces Cr-containing volatile species at SOFC operating temperatures and conditions, which can cause cathode poisoning. Electrically conducting spinel coatings have been developed to prevent cathode poisoning and to maintain an electrically conductive pathway through SOFC stacks. However, this coating is not compatible with the formation of stable, hermetic seals between the interconnect frame component and the ceramic cell. Thus, a new aluminizing process has been developed by PNNL to enable durable sealing, prevent Cr evaporation, and maintain electrical insulation between stack repeat units. Hence, two different types of coating need to have stable operation of SOFC stacks. This paper will focus on the electrically conductive coating process. Moreover, an advanced coating process, compatible with a non-electrically conductive coating will be

Comments on process of duplex coatings on aluminum alloys

Institute of Scientific and Technical Information of China (English)

Samir H.A.; QIAN Han-cheng(钱翰城); XIA Bo-cai(夏伯才); WU Shi-ming(吴仕明)

2004-01-01

Despite the great achievements made in improvement of wear resistance properties of aluminum alloys,their applications in heavy surface load-bearing are limited. Single coating is insufficient to produce the desired combination of surface properties. These problems can be solved through the duplex coatings. The aim of the present study is to overview the research advances on processes of duplex coatings on aluminum alloys combined with micro plasma oxidation process and with other modern processes such as physical vapour deposition and plasma assisted chemical vapour deposition and also to evaluate the performance of micro plasma oxidation coatings in improving the load-bearing, friction and wear resistance properties of aluminum alloys in comparison with other coatings. Wherein, a more detailed presentation of the processes and their performances and disadvantages are given as well.

Photonometers for coating and sputtering machines

Science.gov (United States)

Oupický, P.; Jareš, D.; Václavík, J.; Vápenka, D.

2013-04-01

The concept of photonometers (alternative name of optical monitor of a vacuum deposition process) for coating and sputtering machines is based on photonometers produced by companies like SATIS or HV Dresden. Photometers were developed in the TOPTEC centre and its predecessor VOD (Optical Development Workshop of Institut of Plasma Physics AS CR) for more than 10 years. The article describes current status of the technology and ideas which will be incorporated in next development steps. Hardware and software used on coating machines B63D, VNA600 and sputtering machine UPM810 is presented.

Analyses on Silicide Coating for LOCA Resistant Cladding

Energy Technology Data Exchange (ETDEWEB)

Sweidan, Faris B.; Lee, You Ho; Ryu, Ho Jin [KAIST, Daejeon (Korea, Republic of)

2015-10-15

A particular focus of accident-tolerant fuel has been cladding due to the rapid high-temperature oxidation of zirconium-based cladding with the evolution of H2 when steam is a reactant. Some key features of the coated cladding include high-temperature resistance to oxidation, lower processing temperatures, and a high melting point of the coating. Zirconium alloys exhibit a reasonably high melting temperature, so a coating for the cladding is appealing if the coating increases the high-temperature resistance to oxidation. In this case, the cladding is protected from complete oxidation. The cladding coating involves the application of zirconium silicide onto Zr-based cladding. Zirconium silicide coating is expected to produce a glassy layer that becomes more protective at elevated temperature. For this reason, silicide coatings on cladding offer the potential for improved reliability at normal operating temperatures and at the higher transient temperatures encountered during accidents. Although ceramic coatings are brittle and may have weak points to be used as coating materials, several ceramic coatings were successful and showed adherent behavior and high resistance to oxidation. In this study, the oxidation behavior of zirconium silicide and its oxidation kinetics are analyzed. Zirconium silicide is a new suggested material to be used as coatings on existing Zr-based cladding alloys, the aim of this study is to evaluate if zirconium silicide is applicable to be used, so they can be more rapidly developed using existing cladding technology with some modifications. These silicide coatings are an attractive alternative to the use of coatings on zirconium claddings or to the lengthy development of monolithic ceramic or ceramic composite claddings and coatings.

Analyses on Silicide Coating for LOCA Resistant Cladding

International Nuclear Information System (INIS)

Sweidan, Faris B.; Lee, You Ho; Ryu, Ho Jin

2015-01-01

A particular focus of accident-tolerant fuel has been cladding due to the rapid high-temperature oxidation of zirconium-based cladding with the evolution of H2 when steam is a reactant. Some key features of the coated cladding include high-temperature resistance to oxidation, lower processing temperatures, and a high melting point of the coating. Zirconium alloys exhibit a reasonably high melting temperature, so a coating for the cladding is appealing if the coating increases the high-temperature resistance to oxidation. In this case, the cladding is protected from complete oxidation. The cladding coating involves the application of zirconium silicide onto Zr-based cladding. Zirconium silicide coating is expected to produce a glassy layer that becomes more protective at elevated temperature. For this reason, silicide coatings on cladding offer the potential for improved reliability at normal operating temperatures and at the higher transient temperatures encountered during accidents. Although ceramic coatings are brittle and may have weak points to be used as coating materials, several ceramic coatings were successful and showed adherent behavior and high resistance to oxidation. In this study, the oxidation behavior of zirconium silicide and its oxidation kinetics are analyzed. Zirconium silicide is a new suggested material to be used as coatings on existing Zr-based cladding alloys, the aim of this study is to evaluate if zirconium silicide is applicable to be used, so they can be more rapidly developed using existing cladding technology with some modifications. These silicide coatings are an attractive alternative to the use of coatings on zirconium claddings or to the lengthy development of monolithic ceramic or ceramic composite claddings and coatings

Effect of coating density on oxidation resistance and Cr vaporization from solid oxide fuel cell interconnects

DEFF Research Database (Denmark)

Talic, Belma; Falk-Windisch, Hannes; Venkatachalam, Vinothini

2017-01-01

•Protective action of dense and porous spinel coatings on Crofer 22 APU was compared. •Reduction and re-oxidation produces denser coatings than heat treating in air only. •Coating density has minor influence on oxidation resistance at 800 °C in air. •Dense coating resulted in three times lower Cr...... evaporation rate than porous coating....

Application of aluminum diffusion coatings to mitigate the KCl-induced high-temperature corrosion

DEFF Research Database (Denmark)

Kiamehr, Saeed; Lomholt, T. N.; Dahl, Kristian Vinter

2017-01-01

Pack cementation was used to produce Fe1−xAl and Fe2Al5 diffusion coatings on ferritic-martensitic steel P91 and a Ni2Al3 diffusion coating on pure nickel. The performance of diffusion coatings against high-temperature corrosion induced by potassium chloride (KCl) was evaluated by exposing...

Fault-tolerant epoxy-silane coating for corrosion protection of magnesium alloy AZ31

NARCIS (Netherlands)

Lamaka, S.V.; Xue, H.B.; Meis, N.N.A.H.; Esteves, A.C.C.; Ferreira, M.G.S.

2015-01-01

In this work, a hybrid epoxy-silane coating was developed for corrosion protection of magnesium alloy AZ31. The average thickness of the film produced by dip-coating procedure was 14 µm. The adhesion strength of the epoxy-silane coating to the Mg substrate was evaluated by pull-off tests and was

Improving tribological properties of (Zn–Ni)/nano Al{sub 2}O{sub 3} composite coatings produced by ultrasonic assisted pulse plating

Energy Technology Data Exchange (ETDEWEB)

Ataie, Sayed Alireza, E-mail: ataie_s_alireza@metaleng.iust.ac.ir; Zakeri, Alireza

2016-07-25

In this study pulse electroplating was used to deposit the composite coating of (Zn–Ni) strengthened by Al{sub 2}O{sub 3} nanoparticles on mild steel plate. The effect of Al{sub 2}O{sub 3} fraction and ultrasonic irradiation on the properties of the composite coating was also investigated. Scanning electron microscopy and energy dispersive spectroscopy techniques were employed to characterize the morphology and composition of the coating. Topography and surface roughness were investigated by atomic force microscopy. Also in order to evaluate the mechanical properties of the coating micro hardness and wear tests were conducted. It was found that coating hardness was increased from 538 HV to 750 HV and friction coefficient was decreased from 0.588 to 0.392. Results revealed that tribological properties of coating could be improved significantly by using suitable ultrasonic intensity simultaneously with pulse plating. - Highlights: • SEM indicated on the elimination of cracks and pores when ultrasounds were used. • XRD result showed nano sized grains of Zn–Ni matrix was developed in this research. • Simultaneous pulse plating and ultrasonic conditions improved the properties of the coating. • A (Zn–Ni)/nano alumina uniform composite coating for especial applications was developed. • Micro hardness and wear behavior of the coating was modified by intensifying the ultrasound.

Corrosion issues of powder coated AA6060 aluminium profiles

DEFF Research Database (Denmark)

Din, Rameez Ud; Valgarðsson, Smári; Jellesen, Morten Stendahl

2015-01-01

In this study detailed microstructural investigation of the reason for unexpected corrosion of powder coated aluminium alloy AA6060 windows profiles has been performed. The results from this study reveals that the failure of the window profiles was originated from the surface defects present...... on the extruded AA6060 aluminium profile after metallurgical process prior to powder coating. Surface defects are produced due to intermetallic particles in the alloy, which disturb the flow during the extrusion process. The corrosion mechanism leading to the failure of the powder coated AA6060 aluminium profiles...

Development of high-index optical coating for security holograms

Science.gov (United States)

Ahmed, Nadir A. G.

2000-10-01

Over the past few years security holograms have grown into a complex business to prevent counterfeiting of security cards, banknotes and the like. Rapid advances in holographic technology have led to a growing requirement for optical materials and coating methods to produce such holograms at reasonable costs. These materials have specific refractive indices and are used to fabricate semi- transparent holograms. The present paper describes a coating process to deposit optical coating on flexible films inside a vacuum web metallizer for the production of high quality semi-transparent holograms.

Effect of Anode Dielectric Coating on Hall Thruster Operation

International Nuclear Information System (INIS)

Dorf, L.; Raitses, Y.; Fisch, N.J.; Semenov, V.

2003-01-01

An interesting phenomenon observed in the near-anode region of a Hall thruster is that the anode fall changes from positive to negative upon removal of the dielectric coating, which is produced on the anode surface during the normal course of Hall thruster operation. The anode fall might affect the thruster lifetime and acceleration efficiency. The effect of the anode coating on the anode fall is studied experimentally using both biased and emissive probes. Measurements of discharge current oscillations indicate that thruster operation is more stable with the coated anode

Preparation of biodegradable magnetic microspheres with poly(lactic acid)-coated magnetite

Energy Technology Data Exchange (ETDEWEB)

Zhao Hong; Saatchi, Katayoun [Faculty of Pharmaceutical Sciences, University of British Columbia, 2146 East Mall, Vancouver, BC, 6T 1Z3 (Canada); Haefeli, Urs O. [Faculty of Pharmaceutical Sciences, University of British Columbia, 2146 East Mall, Vancouver, BC, V6T 1Z3 (Canada)], E-mail: uhafeli@interchange.ubc.ca

2009-05-15

Poly(lactic acid) (PLA)-coated magnetic nanoparticles were made using uncapped PLA with free carboxylate groups. The physical properties of these particles were compared to those of oleate-coated or oleate/sulphonate bilayer (W40) coated magnetic particles. Magnetic microspheres (MMS) with the matrix material poly(lactide-co-glycolide) (PLGA) or PLA were then formed by the emulsion solvent extraction method with encapsulation efficiencies of 40%, 83% and 96% for oleate, PLA and oleate/sulfonate-coated magnetic particles, respectively. MMS made from PLA-coated magnetite were hemocompatible and produced no hemolysis, whereas the other MMS were hemolytic above 0.3 mg/mL of blood.

Preparation of biodegradable magnetic microspheres with poly(lactic acid)-coated magnetite

International Nuclear Information System (INIS)

Zhao Hong; Saatchi, Katayoun; Haefeli, Urs O.

2009-01-01

Poly(lactic acid) (PLA)-coated magnetic nanoparticles were made using uncapped PLA with free carboxylate groups. The physical properties of these particles were compared to those of oleate-coated or oleate/sulphonate bilayer (W40) coated magnetic particles. Magnetic microspheres (MMS) with the matrix material poly(lactide-co-glycolide) (PLGA) or PLA were then formed by the emulsion solvent extraction method with encapsulation efficiencies of 40%, 83% and 96% for oleate, PLA and oleate/sulfonate-coated magnetic particles, respectively. MMS made from PLA-coated magnetite were hemocompatible and produced no hemolysis, whereas the other MMS were hemolytic above 0.3 mg/mL of blood.

Figure correction of multilayer coated optics

Science.gov (United States)

Chapman; Henry N. , Taylor; John S.

2010-02-16

A process is provided for producing near-perfect optical surfaces, for EUV and soft-x-ray optics. The method involves polishing or otherwise figuring the multilayer coating that has been deposited on an optical substrate, in order to correct for errors in the figure of the substrate and coating. A method such as ion-beam milling is used to remove material from the multilayer coating by an amount that varies in a specified way across the substrate. The phase of the EUV light that is reflected from the multilayer will be affected by the amount of multilayer material removed, but this effect will be reduced by a factor of 1-n as compared with height variations of the substrate, where n is the average refractive index of the multilayer.

Fire resistance properties of ceramic wool fiber reinforced intumescent coatings

Energy Technology Data Exchange (ETDEWEB)

Amir, N., E-mail: norlailiamir@petronas.com.my; Othman, W. M. S. W., E-mail: wamosa@gmail.com; Ahmad, F., E-mail: faizahmad@petronas.com.my [Mechanical Engineering Department, Universiti Teknologi PETRONAS Bandar Seri Iskandar, 31750 Tronoh, Perak (Malaysia)

2015-07-22

This research studied the effects of varied weight percentage and length of ceramic wool fiber (CWF) reinforcement to fire retardant performance of epoxy-based intumescent coating. Ten formulations were developed using ammonium polyphosphate (APP), expandable graphite (EG), melamine (MEL) and boric acid (BA). The mixing was conducted in two stages; powdered materials were grinded in Rocklabs mortar grinder and epoxy-mixed using Caframo mixer at low speed mixing. The samples were applied on mild steel substrate and exposed to 500°C heat inside Carbolite electric furnace. The char expansion and its physical properties were observed. Scanning electron microscopy (SEM) analyses were conducted to inspect the fiber dispersion, fiber condition and the cell structure of both coatings and chars produced. Thermogravimetric analyses (TGA) were conducted to study the thermal properties of the coating such as degradation temperature and residual weight. Fire retardant performance was determined by measuring backside temperature of substrate in 1-hour, 1000°C Bunsen burner test according to UL 1709 fire regime. The results showed that intumescent coating reinforced with CWF produced better fire resistance performance. When compared to unreinforced coating, formulation S6-15 significantly reduced steel temperature at approximately 34.7% to around 175°C. However, higher fiber weight percentage had slightly decreased fire retardant performance of the coating.

Fire resistance properties of ceramic wool fiber reinforced intumescent coatings

International Nuclear Information System (INIS)

Amir, N.; Othman, W. M. S. W.; Ahmad, F.

2015-01-01

This research studied the effects of varied weight percentage and length of ceramic wool fiber (CWF) reinforcement to fire retardant performance of epoxy-based intumescent coating. Ten formulations were developed using ammonium polyphosphate (APP), expandable graphite (EG), melamine (MEL) and boric acid (BA). The mixing was conducted in two stages; powdered materials were grinded in Rocklabs mortar grinder and epoxy-mixed using Caframo mixer at low speed mixing. The samples were applied on mild steel substrate and exposed to 500°C heat inside Carbolite electric furnace. The char expansion and its physical properties were observed. Scanning electron microscopy (SEM) analyses were conducted to inspect the fiber dispersion, fiber condition and the cell structure of both coatings and chars produced. Thermogravimetric analyses (TGA) were conducted to study the thermal properties of the coating such as degradation temperature and residual weight. Fire retardant performance was determined by measuring backside temperature of substrate in 1-hour, 1000°C Bunsen burner test according to UL 1709 fire regime. The results showed that intumescent coating reinforced with CWF produced better fire resistance performance. When compared to unreinforced coating, formulation S6-15 significantly reduced steel temperature at approximately 34.7% to around 175°C. However, higher fiber weight percentage had slightly decreased fire retardant performance of the coating

Fire resistance properties of ceramic wool fiber reinforced intumescent coatings

Science.gov (United States)

Amir, N.; Othman, W. M. S. W.; Ahmad, F.

2015-07-01

This research studied the effects of varied weight percentage and length of ceramic wool fiber (CWF) reinforcement to fire retardant performance of epoxy-based intumescent coating. Ten formulations were developed using ammonium polyphosphate (APP), expandable graphite (EG), melamine (MEL) and boric acid (BA). The mixing was conducted in two stages; powdered materials were grinded in Rocklabs mortar grinder and epoxy-mixed using Caframo mixer at low speed mixing. The samples were applied on mild steel substrate and exposed to 500°C heat inside Carbolite electric furnace. The char expansion and its physical properties were observed. Scanning electron microscopy (SEM) analyses were conducted to inspect the fiber dispersion, fiber condition and the cell structure of both coatings and chars produced. Thermogravimetric analyses (TGA) were conducted to study the thermal properties of the coating such as degradation temperature and residual weight. Fire retardant performance was determined by measuring backside temperature of substrate in 1-hour, 1000°C Bunsen burner test according to UL 1709 fire regime. The results showed that intumescent coating reinforced with CWF produced better fire resistance performance. When compared to unreinforced coating, formulation S6-15 significantly reduced steel temperature at approximately 34.7% to around 175°C. However, higher fiber weight percentage had slightly decreased fire retardant performance of the coating.

EB-curing of coatings on wood composite boards

International Nuclear Information System (INIS)

Czvikovszky, T.; Czajlic, I.; Takacs, E.; Ille, A.; Salleh, N.G.; Alpar, T.

1988-01-01

The industrial radiation processing using low energy electron beam (EB) accelerators lower than 300 keV offers high speed, safe technologies for the chemical conversion of thin layer coatings. Because of the nonselective mode of initiating chain reaction polymerization involving free radicals in synthetic coating layers and suitable substrates, the EB curing of the coatings on woods and papers has particular advantage. Hungary decided to start an up-to-date EB line to process cement-bound (CB) wood chipboards with pigmented acrylic coatings. The CB wood chipboards contain more than 60 % of portland cement and up to 40 % of wood particles. They are produced as large boads of 6 - 16 mm thickness. In their fireproof character and other aspects, they are similar to asbestos-cement boards without containing carcinagenic asbestos, and are stable against moisture and atmospheric influences. EB-cured acrylate coating improved further those properties, and makes them valuable structural material. Oligomers and monomers as the main components of EB curable coatings, the irradiation with a Van de Graaff type electron accelerator of 2 MeV and the results are reported. The oligomers play the most important role in the formation of radiation curable coatings. (K.I.)

Improved coating and fixation methods for scanning electron microscope autoradiography

International Nuclear Information System (INIS)

Weiss, R.L.

1984-01-01

A simple apparatus for emulsion coating is described. The apparatus is inexpensive and easily assembled in a standard glass shop. Emulsion coating for scanning electron microscope autoradiography with this apparatus consistently yields uniform layers. When used in conjunction with newly described fixation methods, this new approach produces reliable autoradiographs of undamaged specimens

Synthesis of mullite-based coatings from alumina and zircon powder mixtures by plasma spraying and laser remelting

International Nuclear Information System (INIS)

Hazra, S.; Das, J.; Bandyopadhyay, P.P.

2015-01-01

A mechanical mixture of alumina and pulverized zircon sand in 3:2 M ratio has been plasma sprayed to obtain mullite coating. Thereafter, the top layer of the coating has been remelted using laser. The presence of a mullite phase in the as-sprayed and laser remelted coatings has been confirmed qualitatively using X-ray diffraction. Both as-sprayed and laser remelted coatings have been characterized for their microstructure, hardness and porosity. The ultrafine grain structure of the coating produced by rapid quenching has been analyzed using transmission electron microscope. Presence of a mullite phase in the coatings has also been confirmed using small angle electron diffraction. Laser remelting has resulted in an appreciable reduction in porosity and increase in hardness in the coatings. - Highlights: • Mullite has been produced by plasma spraying of alumina–zircon powder mixture. • As sprayed coating shows good integrity. • Laser remelting reduced porosity and increased coating hardness

Synthesis of mullite-based coatings from alumina and zircon powder mixtures by plasma spraying and laser remelting

Energy Technology Data Exchange (ETDEWEB)

Hazra, S. [Integrated Test Range, Chandipur, Balasore, Odisha 756025 (India); Das, J. [Department of Metallurgical and Materials Engineering, IIT Kharagpur, 721302 (India); Bandyopadhyay, P.P., E-mail: ppb@mech.iitkgp.ernet.in [Department of Mechanical Engineering, IIT Kharagpur, 721302 (India)

2015-03-15

A mechanical mixture of alumina and pulverized zircon sand in 3:2 M ratio has been plasma sprayed to obtain mullite coating. Thereafter, the top layer of the coating has been remelted using laser. The presence of a mullite phase in the as-sprayed and laser remelted coatings has been confirmed qualitatively using X-ray diffraction. Both as-sprayed and laser remelted coatings have been characterized for their microstructure, hardness and porosity. The ultrafine grain structure of the coating produced by rapid quenching has been analyzed using transmission electron microscope. Presence of a mullite phase in the coatings has also been confirmed using small angle electron diffraction. Laser remelting has resulted in an appreciable reduction in porosity and increase in hardness in the coatings. - Highlights: • Mullite has been produced by plasma spraying of alumina–zircon powder mixture. • As sprayed coating shows good integrity. • Laser remelting reduced porosity and increased coating hardness.

Effects of Laser Re-melting on the Corrosion Properties of HVOF Coatings

Science.gov (United States)

Yilbas, B. S.; Toor, I. H.; Patel, F.; Baig, M. A.

2013-05-01

HVOF coating of Inconel 625 powder on carbon steel is carried out. Laser melting of the resulting coating is realized to improve coating structural integrity. Morphological and microstructural changes are examined in the coating prior and after laser treatment process using scanning electron microscopy, energy dispersive spectroscopy, and x-ray diffraction (XRD). The residual stress developed is measured on the surface vicinity of the laser-treated coating using the XRD technique. The corrosion resistance of the laser-treated and untreated coating surfaces is measured, incorporating the potentiodynamic tests in 0.5 M NaCl aqueous solution. It is found that laser treatment reduces the pores and produces cellular structures with different sizes and orientations in the coating. Laser-controlled melting improves the corrosion resistance of the coating surface.

Minimizing resputtering of Pt-coated microspheres in a batch magnetron sputtering process

International Nuclear Information System (INIS)

Plake, A.L.

1981-01-01

Preventing DT loss from glass microspheres being smoothly coated with PT is needed during fabrication of laser fusion targets. Evidence indicates that the increase of substrate temperature due to resputtering will cause DT loss. Resputtering will prevent a smooth and uniform coating on these glass microspheres (140 μm in diameter). This paper reviews the method that was developed to find a set of coating conditions to minimize the DT loss, and still be able to produce thick smooth Pt coated glass microspheres

NB Coating Developments with HIPIMS for SRF Applications

CERN Document Server

Terenziani, G; Junginger, T; Santillana, I A; Ehiasarian, A P

2013-01-01

In the last few years the interest of the thin film science and technology community on High Impulse Power Magnetron Sputtering (HIPIMS) coatings has steadily increased. HIPIMS literature shows that better thin film morphology, denser and smoother films can be achieved when compared with standard dc Magnetron Sputtering (dcMS) coating technology [1]. Furthermore the capability of HIPIMS to produce a high quantity of ionized species [2,3] can allow conformal coatings also for complex geometries. A study is under way at CERN to apply this technology for the Nb coating of SRF 1.3-1.5 GHz Cu cavities, and in parallel at SHU the plasma physics and its correlation with film morphology are being investigated [2]. Recent results achieved with this technique are presented in the paper.

Effect of adhesive properties of buffy coat on the quality of blood components produced with Top & Top and Top & Bottom bags.

Science.gov (United States)

Cerelli, Eugenio; Nocera, Martina; Di Bartolomeo, Erminia; Panzani, Paola; Baricchi, Roberto

2015-04-01

The Transfusion Medicine Unit of Reggio Emilia currently collects whole blood using conventional quadruple Fresenius Top & Top bags. In this study, new Fresenius Top & Bottom bags were assessed and compared to the routine method with regards to product quality and operational requirements. Twenty-one whole blood units were collected with both the new and the traditional bags, and then separated. Quality control data were evaluated and compared in order to estimate yield and quality of final blood components obtained with the two systems. We collected other bags, not included in the ordinary quality control programme, for comparison of platelet concentrates produced by pools of buffy coat. Compared to the traditional system, the whole blood units processed with Top & Bottom bags yielded larger plasma volumes (+5.7%) and a similar amount of concentrated red blood cells, but with a much lower contamination of lymphocytes (-61.5%) and platelets (-86.6%). Consequently, the pooled platelets contained less plasma (-26.3%) and were significantly richer in platelets (+17.9%). This study investigated the effect of centrifugation on the adhesiveness of the buffy coat to the bag used for whole blood collection. We analysed the mechanism by which this undesirable phenomenon affects the quality of packed red blood cells in two types of bags. We also documented the incomparability of measurements on platelet concentrates performed with different principles of cell counting: this vexing problem has important implications for biomedical research and for the establishment of universal product standards. Our results support the conclusion that the Top & Bottom bags produce components of higher quality than our usual system, while having equal operational efficiency. Use of the new bags could result in an important quality improvement in blood components manufacturing.

Tribosystems based on multilayered micro/nanocrystalline CVD diamond coatings =

Science.gov (United States)

Shabani, Mohammadmehdi

A combinacao das caracteristicas do diamante microcristalino (MCD) e nanocristalino (NCD), tais como elevada adesao do MCD e a baixa rugosidade superficial e baixo coeficiente de atrito do NCD, e ideal para aplicacoes tribologicas exigentes. Deste modo, o presente trabalho centrou-se no desenvolvimento de revestimentos em multicamada MCD/NCD. Filmes com dez camadas foram depositados em amostras de cerâmicos de Si3N4 pela tecnica de deposicao quimica em fase vapor assistida por filamento quente (HFCVD). A microestrutura, qualidade do diamante e adesao foram investigadas usando tecnicas como SEM, AFM, espectroscopia Raman, DRX, indentacao Brale e perfilometria otica 3D. Diversas geometrias para aplicacoes distintas foram revestidas: discos e esferas para testes tribologicos a escala laboratorial, e para testes em servico, aneis de empanques mecânicos e pastilhas de corte para torneamento. Nos ensaios tribologicos esfera-sobre-plano em movimento reciproco, sob 10-90% de humidade relativa (RH), os valores medios dos coeficientes de atrito maximo e em estado estacionario sao de 0,32 e 0,09, respetivamente. Em relacao aos coeficientes de desgaste, observou-se um valor minimo de cerca de 5,2x10-8 mm3N-1m-1 para valores intermedios de 20-25% de RH. A humidade relativa tem um forte efeito sobre o valor da carga critica que triplica a partir de 40 N a 10% RH para 120 N a 90% de RH. No intervalo de temperaturas 50-100 °C, as cargas criticas sao semelhantes as obtidas em condicoes de baixa RH ( 10-25%). A vida util das ferramentas com revestimento de dez camadas alternadas MCD/NCD e 24 mum de espessura total no torneamento de um composito de matriz metalica Al- 15 vol% Al2O3 (Al-MMC) e melhor do que a maioria das ferramentas de diamante CVD encontradas na literatura, e semelhante a maioria das ferramentas de diamante policristalino (PCD). A formacao de cratera ocorre por desgaste sucessivo das varias camadas, atrasando a delaminacao total do revestimento de diamante do

Large area diamond-like carbon coatings by ion implantation

International Nuclear Information System (INIS)

McCabe, A.R.; Proctor, G.; Jones, A.M.; Bull, S.J.; Chivers, D.J.

1993-01-01

Diamond-like Carbon (DLC) coatings have been deposited onto large geometry components in the Harwell Blue Tank ion implantation facility. To modify the substrate surface and to crack the low vapour pressure oil which is evaporated and condensed onto the surface, a 40 Kev nitrogen ion bucket ion source is used. The coating of areas up to 1 metre in diameter is common and with component manipulation larger areas may be coated. Since the component temperature never exceeds 80 o C during the process, a wide range of materials may be coated including specialist tool steels and even certain high density polymers. In order to produce hard wear resistant coatings with extremely low coefficients of friction (0.02-0.15) and a range of mechanical and electrical properties, various oil precursors have been investigated. The production and assessment of such coatings, including measurements of their tribiological performance, is presented. Applications for wear resistance, corrosion protection and electrically conducting coatings are discussed with examples drawn from engineering, electronics and biomedicine. (7 figures, 13 references). (UK)

TRISO coated fuel particles with enhanced SiC properties

International Nuclear Information System (INIS)

Lopez-Honorato, E.; Tan, J.; Meadows, P.J.; Marsh, G.; Xiao, P.

2009-01-01

The silicon carbide (SiC) layer used for the formation of TRISO coated fuel particles is normally produced at 1500-1650 deg. C via fluidized bed chemical vapor deposition from methyltrichlorosilane in a hydrogen environment. In this work, we show the deposition of SiC coatings with uniform grain size throughout the coating thickness, as opposed to standard coatings which have larger grain sizes in the outer sections of the coating. Furthermore, the use of argon as the fluidizing gas and propylene as a carbon precursor, in addition to hydrogen and methyltrichlorosilane, allowed the deposition of stoichiometric SiC coatings with refined microstructure at 1400 and 1300 deg. C. The deposition of SiC at lower deposition temperatures was also advantageous since the reduced heat treatment was not detrimental to the properties of the inner pyrolytic carbon which generally occurs when SiC is deposited at 1500 deg. C. The use of a chemical vapor deposition coater with four spouts allowed the deposition of uniform and spherical coatings.

Effect of SnO2/SiO2 nano particle dispersant on the performance characteristic of complex multi-doped composite coating produced through electrodeposition on oil and gas storage tap

Directory of Open Access Journals (Sweden)

P.A.L. Anawe

2018-06-01

Full Text Available The effect of SnO2/SiO2 nano particle dispersant on the performance characteristic of complex zinc multi-doped composite coating produced through electrodeposition is studied. The degradation behaviour in term of wear and chemical corrosion activities were considered as a major factor in service. The wear mass loss was carried out with the help of reciprocating tester. The electrochemical corrosion characteristics were investigated using linear polarization technique in 3.5% simulated sodium chloride media. The outcome of the analysis shows that the developed coating was seen to provide a sound anti wear characteristics in its multidoped state. The corrosion resistance properties were observed to be massive compared to the binary based sample. It is expected that this characteristic will impact on the performance life span of storage tap in oil and gas. Keywords: Zn-SnO2-SiO2, Nanocomposite, Electrodeposition, Coatings and corrosion resistance

Selected properties of laser cladding coatings shaped using Flow drill technology

Directory of Open Access Journals (Sweden)

Bartkowski Dariusz

2017-01-01

Full Text Available The paper presents the investigations of selected chemical and mechanical properties as well as macro- and microstructure of materials formed using thermal drilling process (Flow drill. The aim of this study was to determine the microstructure of the coatings produced using laser cladding with powder technology. The coatings were produced on the low-carbon steel using 1 kW disc laser. After modification of surface, the thermal drilling process was applied. To produce all coatings, the pure copper powder was used. In this study the laser power equal of 500, 700 and 900 W were used. The microstructure, chemical composition (EDS and microhardness were investigation. It was found that the surface modification of low carbon steel and next conducted thermal drilling process caused change the surface properties on the hole flange. It was found that surface modification of steel using laser cladding with cooper powder and next Flow drill process contributes to the change in microhardness and chemical composition on hole flange.

Novel Fouling-Reducing Coatings for Ultrafiltration, Nanofiltration, and Reverse Osmosis Membranes

Energy Technology Data Exchange (ETDEWEB)

Benny Freeman

2008-08-31

Polymeric membranes could potentially be the most flexible and viable long-term strategy for treatment of produced water from oil and gas production. However, widespread use of membranes, including reverse osmosis (RO) membranes, for produced water purification is hindered due to fouling caused by the impurities present in the water. Fouling of RO membranes is likely caused by surface properties including roughness, hydrophilicity, and charge, so surface modification is the most widely considered approach to improve the fouling properties of current RO membranes. This project focuses on two main approaches to surface modification: coating and grafting. Hydrophilic coating and grafting materials based on poly(ethylene glycol) (PEG) are applied to commercial RO membranes manufactured by Dow FilmTec and GE. Crossflow filtration experiments are used to determine the fouling resistance of modified membranes, and compare their performance to that of unmodified commercial RO membranes. Grafting and coating are shown to be two alternative methods of producing modified membranes with improved fouling resistance.

Biased HiPIMS technology for superconducting rf accelerating cavities coating

CERN Document Server

G. Rosaz, G.; Sonato, D.; Calatroni, S.; Ehiasarian, A.; Junginger, T.; Taborelli, M.

2016-01-01

In the last few years the interest of the thin film science and technology community on High Impulse Power Magnetron Sputtering (HIPIMS) coatings has steadily increased. HIPIMS literature shows that better thin film morphology, denser and smoother films can be achieved when compared with standard dc Magnetron Sputtering (dcMS) coating technology. Furthermore the capability of HIPIMS to produce a high quantity of ionized species can allow conformal coatings also for complex geometries. CERN already studied the possibility to use such a coating method for SRF accelerating cavities. Results are promising but not better from a RF point of view than dcMS coatings. Thanks to these results the next step is to go towards a biased HiPIMS approach. However the geometry of the cavities leads to complex changes in the coating setup in order to apply a bias voltage. Coating system tweaking and first superconducting properties of biased samples are presented.

Laser cladding of Inconel 625-based composite coatings reinforced by porous chromium carbide particles

Science.gov (United States)

Janicki, Damian

2017-09-01

Inconel 625/Cr3C2 composite coatings were produced via a laser cladding process using Cr3C2 reinforcing particles presenting an open porosity of about 60%. A laser cladding system used consisted of a direct diode laser with a rectangular beam spot and the top-hat beam profile, and an off-axis powder injection nozzle. The microstructural characteristics of the coatings was investigated with the use of scanning electron microscopy and X-ray diffraction. A complete infiltration of the porous structure of Cr3C2 reinforcing particles and low degree of their dissolution have been achieved in a very narrow range of processing parameters. Crack-free composite coatings having a uniform distribution of the Cr3C2 particles and their fraction up to 36 vol% were produced. Comparative erosion tests between the Inconel 625/Cr3C2 composite coatings and the metallic Inconel 625 coatings were performed following the ASTM G 76 standard test method. It was found that the composite coatings have a significantly higher erosion resistance to that of metallic coatings for both 30° and 90° impingement angles. Additionally, the erosion performances of composite coatings were similar for both the normal and oblique impact conditions. The erosive wear behaviour of composite coatings is discussed and related to the unique microstructure of these coatings.

Using sol-gel component as additive to foundry coatings to improve casting quality

DEFF Research Database (Denmark)

Nwaogu, Ugochukwu Chibuzoh; Poulsen, T.; Gravesen, B.

2012-01-01

The improvement of foundry coatings to enhance performance is important. This paper investigates the effect of using sol‐gel component as an additive to foundry coatings applied on chemically bonded sand cores. Three parameters at three levels each were investigated using Taguchi experimental...... was evaluated. The results show that the surface quality of castings obtained by adding the sol‐gel component to the coatings for cold box cores has no significant difference from castings produced with coatings without sol‐gel component. On the other hand, the addition of the sol‐gel component in coatings...

Wear behavior of niobium carbide coated AISI 52100 steel

International Nuclear Information System (INIS)

Fernandes, Frederico Augusto Pires; Casteletti, Luiz Carlos; Oliveira, Carlos Kleber Nascimento de; Lombardi Neto, Amadeu; Totten, George Edward

2010-01-01

Bearing steels must have high hardness, good wear resistance and dimensional stability. The aim of this work was to study the effect of NbC coating, produced using the thermo-reactive deposition (TRD) process, on the wear resistance of the AISI 52100 steel. Untreated AISI 52100 samples were ground up to 600 mesh emery paper. The bath was composed of 5wt.% ferroniobium (65 wt.% Nb), 3wt.% aluminum and (Na2B4O7) to 100%. Samples were treated at 1000 deg C for 4h and quenched in oil directly from the bath. The resulting layer was characterized by X-ray diffraction, scanning electron microscopy and a micro-abrasive wear testing. The thermo-reactive deposition process in molten borax produced a hard and homogeneous layer composed by NbC, which was confirmed by X-ray diffraction. The NbC coating produced a great increase in the wear resistance of the AISI 52100 steel, decreasing the wear rate by an order of magnitude in relation to the substrate. For coated and uncoated samples the worn volume and wear rate increases with the load. (author)

Improving the packing density of calcium phosphate coating on a magnesium alloy for enhanced degradation resistance.

Science.gov (United States)

Kannan, M Bobby

2013-05-01

In this study, an attempt was made to improve the packing density of calcium phosphate (CaP) coating on a magnesium alloy by tailoring the coating solution for enhanced degradation resistance of the alloy for implant applications. An organic solvent, ethanol, was added to the coating solution to decrease the conductivity of the coating solution so that hydrogen bubble formation/bursting reduces during the CaP coating process. Experimental results confirmed that ethanol addition to the coating solution reduces the conductivity of the solution and also decreases the hydrogen evolution/bubble bursting. In vitro electrochemical experiments, that is, electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization showed that CaP coating produced in 30% (v/v) ethanol containing coating solution (3E) exhibits significantly higher degradation resistance (i.e., ~50% higher polarization resistance and ~60% lower corrosion current) than the aqueous solution coating. Scanning electron microscope (SEM) analysis of the coatings revealed that the packing of 3E coating was denser than that of aqueous coating, which can be attributed to the lower hydrogen evolution in the former than in the latter. Further increase in the ethanol content in the coating solution was not beneficial; in fact, the coating produced in 70% (v/v) ethanol containing solution (7E) showed degradation resistance much inferior to that of the aqueous coating, which is due to low thickness of 7E coating. Copyright © 2012 Wiley Periodicals, Inc.

THERMAL COMPOSITE COATINGS IMPROVING QUALITY OF TECHNICAL MEANS OF TRANSPORT

Directory of Open Access Journals (Sweden)

Andrzej POSMYK

2015-06-01

Full Text Available The paper presents the thermal properties of composite insulating material designed for producing of technical means of transport. This material can be coated on most of engineering materials. The matrix of this material is an acrylic resin ant non porous ceramic microspheres made of alumina are the reinforcing phase. Thanks to that into the spheres almost vacuum (0,13 Pa dominants and a big amount of spheres pro thickness unit is it possible to achieve low thermal conductivity. Usage of these coatings for producing of cooling cabins on vehicles let us to reduce of fuel for maintain of given temperature. Usage of these coatings in planes flying on high altitudes (temperature up to -60 allows to reduce of fuel consumption for heating. It has an important influence on transport quality and quality costs.

European coatings conference - Marine coatings. Proceedings

Energy Technology Data Exchange (ETDEWEB)

NONE

2008-07-01

This volume contains 13 lectures (manuscripts or powerpoint foils) with the following topics: 1. Impact of containerization on polyurethane and polyurea in marine and protective coatings (Malte Homann); 2. The application of combinatorial/high-throughput methods to the development of marine coatings (Bret Chisholm); 3. Progress and perspectives in the AMBIO (advanced nanostructured surfaces for the control of biofouling) Project (James Callow); 4. Release behaviour due to shear and pull-off of silicone coatings with a thickness gradient (James G. Kohl); 5. New liquid rheology additives for high build marine coatings (Andreas Freytag); 6. Effective corrosion protection with polyaniline, polpyrrole and polythiophene as anticorrosice additives for marine paints (Carlos Aleman); 7. Potential applications of sol gel technology for marine applications (Robert Akid); 8: Performance of biocide-free Antifouling Coatings for leisure boats (Bernd Daehne); 9. Novel biocidefree nanostructured antifouling coatings - can nano do the job? (Corne Rentrop); 10. One component high solids, VOC compliant high durability finish technology (Adrian Andrews); 11. High solid coatings - the hybrid solution (Luca Prezzi); 12. Unique organofunctional silicone resins for environmentally friendly high-performance coatings (Dieter Heldmann); 13. Silicone-alkyd paints for marine applications: from battleship-grey to green (Thomas Easton).

Plasma Sprayed Hydroxyapatite Coatings: Influence of Spraying Power on Microstructure

International Nuclear Information System (INIS)

Mohd, S. M.; Abd, M. Z.; Abd, A. N.

2010-01-01

The plasma sprayed hydroxyapatite (HA) coatings are used on metallic implants to enhance the bonding between the implant and bone in human body. The coating process was implemented at different spraying power for each spraying condition. The coatings formed from a rapid solidification of molten and partly molten particles that impact on the surface of substrate at high velocity and high temperature. The study was concentrated on different spraying power that is between 23 to 31 kW. The effect of different power on the coatings microstructure was investigated using scanning electron microscope (SEM) and phase composition was evaluated using X-ray diffraction (XRD) analysis. The coatings surface morphology showed distribution of molten, partially melted particles and some micro-cracks. The produced coatings were found to be porous as observed from the cross-sectional morphology. The coatings XRD results indicated the presence of crystalline phase of HA and each of the patterns was similar to the initial powder. Regardless of different spraying power, all the coatings were having similar XRD patterns.

Structure and corrosion properties of PVD Cr-N coatings

International Nuclear Information System (INIS)

Liu, C.; Bi, Q.; Ziegele, H.; Leyland, A.; Matthews, A.

2002-01-01

PVD Cr-N coatings produced by physical vapor deposition (PVD) are increasingly used for mechanical and tribological applications in various industrial sectors. These coatings are particularly attractive for their excellent corrosion resistance, which further enhances the lifetime and service quality of coated components. PVD Cr-N coated steels in an aqueous solution are usually corroded by galvanic attack via through-coating 'permeable' defects (e.g., pores). Therefore, the corrosion performance of Cr-N coated steel is determined by a number of variables of the coating properties and corrosive environment. These variables include: (i) surface continuity and uniformity; (ii) through-coating porosity; (iii) film density and chemical stability; (iv) growth stresses; (v) interfacial and intermediate layers; (vi) coating thickness; (vii) coating composition; and (viii) substrate properties. In this article, PVD Cr-N coatings were prepared, by electron-beam PVD and sputter deposition, with different compositions, thicknesses, and surface roughnesses, by changing the N 2 flow rate, applying multilayering techniques and changing the substrate finish prior to coating. The microstructure of such coatings is investigated by various analytical techniques such as glancing angle x-ray diffraction and scanning electron microscopy, which are also correlated with the corrosion performance of the coated steel. Both dc polarization and ac impedance spectroscopy were employed to investigate the corrosion resistance of Cr-N coated steel in a 0.5N NaCl solution. It has been found that the N 2 flow rate during reactive deposition strongly determines the microstructure of Cr-N coatings (due to the changing nitrogen content in the film) and can thus affect the corrosion resistance of coated systems. The surface finish of the steel substrate also affects the uniformity and coverage of PVD coatings; grooves and inclusions on the original substrate can raise the susceptibility of coated

Chromate-free Hybrid Coating for Corrosion Protection of Electrogalvanized Steel Sheets

International Nuclear Information System (INIS)

Jo, Duhwan; Kwon, Moonjae; Kim, Jongsang

2012-01-01

Both electrogalvanized and hot-dip galvanized steel sheets have been finally produced via organic-inorganic surface coating process on the zinc surface to enhance corrosion resistance and afford additional functional properties. Recently, POSCO has been developed a variety of chromate-free coated steels that are widely used in household, construction and automotive applications. New organic-inorganic hybrid coating solutions as chromate alternatives are comprised of surface modified silicate with silane coupling agent and inorganic corrosion inhibitors as an aqueous formulation. In this paper we have prepared new type of hybrid coatings and evaluated quality performances such as corrosion resistance, spot weldability, thermal tolerance, and paint adhesion property etc. The electrogalvanized steels with these coating solutions exhibit good anti-corrosion property compared to those of chromate coated steels. Detailed components composition of coating solutions and experimental results suggest that strong binding between organic-inorganic hybrid coating layer and zinc surface plays a key role in the advanced quality performances

Photonometers for coating and sputtering machines

Directory of Open Access Journals (Sweden)

Václavík J.

2013-05-01

Full Text Available The concept of photonometers (alternative name of optical monitor of a vacuum deposition process for coating and sputtering machines is based on photonometers produced by companies like SATIS or HV Dresden. Photometers were developed in the TOPTEC centre and its predecessor VOD (Optical Development Workshop of Institut of Plasma Physics AS CR for more than 10 years. The article describes current status of the technology and ideas which will be incorporated in next development steps. Hardware and software used on coating machines B63D, VNA600 and sputtering machine UPM810 is presented.

Study progression in application of process analytical technologies on film coating

Directory of Open Access Journals (Sweden)

Tingting Peng

2015-06-01

Full Text Available Film coating is an important unit operation to produce solid dosage forms, thereby, the monitoring of this process is helpful to find problems in time and improve the quality of coated products. Traditional methods adopted to monitor this process include measurement of coating weight gain, performance of disintegration and dissolution test, etc. However, not only do these methods cause destruction to the samples, but also consume time and energy. There have recently emerged the applications of process analytical technologies (PAT on film coating, especially some novel spectroscopic and imaging technologies, which have the potential to real-time track the progress in film coating and optimize production efficiency. This article gives an overview on the application of such technologies for film coating, with the goal to provide a reference for the further researches.

Coating materials

International Nuclear Information System (INIS)

Ozeki, Takao; Kimura, Tadashi; Kobayashi, Juichi; Maeda, Yutaka; Nakamoto, Hideo.

1969-01-01

A non-solvent type coating material composition having properties as good as thermosetting acrylic or amino alkid resins is provided by employing active energy irradiation, particularly electron beams, using a radically polymerizable low molecular compound (A) (hereafter called an oligomer) containing at least two vinyl radicals in one molecule. This oligomer is produced by reacting an epoxy-containing vinyl monomer with alpha-, beta-ethylene unsaturated carboxylic acids or their anhydrides. The composition (I) contains 10% - 100% of this oligomer. In embodiments, an oligomer having a fiberous trivinyl construction is produced by reacting 180 parts by weight of glycidyl methacrylate ester with 130 parts of itaconic acid in the presence of a polymerization-inhibitor and an addition reaction catalyst at 90 0 C for 6 hours. In practice, the coating material compositions (1), consist of the whole oligomer [I-1]; (2), consist of 10-90% of (A) component and 90%-10% of vinyl monomers containing at least 30% (meth) acrylic monomer [I-2]; (3), 10%-90% of component (A) and 90%-10% of other monomers containing at least two vinyl radicals [I-3]; (4), a mixture of (I-2) and (I-3), [I-4]; and (5), consist of 50% or less unsaturated polyester of 500-5,000 molecular weight range or drying oil, or alkyd resin of 500-5,000 molecular weight range modified by drying oil, [I-5]. As a catalyst a tertiary amino vinyl compound is preferred. Five examples are given. (Iwakiri, K.)

Coating materials

International Nuclear Information System (INIS)

Ozeki, Takao; Kimura, Tadashi; Kobayashi, Juichi; Maeda, Yutaka; Nakamoto, Hideo.

1969-01-01

A non-solvent type coating material composition is provided which can be hardened by irradiation with active energy, particularly electron beams, using a composition which contains 10%-100% of a radically polymerizable low molecular compound (A), (hereafter called an oligomer), having at least two vinyl radicals in one molecule. These compositions have a high degree of polymerization and characteristics equivalent to thermosetting acrylic or amino alkyd resin. The oligomer (A) is produced by reacting an epoxy-containing vinyl monomer with saturated polycarboxylic acids or anhydrides. In one embodiment, 146 parts by weight of adipic acid and 280 parts of glycidyl methacrylate ester undergo addition reaction in the presence of a polymerization-inhibitor and a catalyst at 90 0 C for 6 hours to produce an oligomer having a fiberous divinyl construction. The coating composition utilizes this oligomer in the forms of (I-1), a whole oligomer; (I-2), 0%-90% of this oligomer and 90%-10% of a vinyl monomer containing at least 30% of (meth) acrylic monomer; (I-3), 10%-90% of such oligomer and 90%-10% of other monomers containing at least two vinyl radicals in one molecule; (I-4), a mixture of (I-2) and (I-3) in proportion of 1/9 to 9/1, and (I-5), above four compositions each containing 50% or less unsaturated polyester or drying oil having 500-5,000 molecules or a drying oil-modified alkyd resin having 500-5,000 molecules. Four examples are given. (Iwakiri, K.)

Cell-derived matrix coatings for polymeric scaffolds.

Science.gov (United States)

Decaris, Martin L; Binder, Bernard Y; Soicher, Matthew A; Bhat, Archana; Leach, J Kent

2012-10-01

Cells in culture deposit a complex extracellular matrix that remains intact following decellularization and possesses the capacity to modulate cell phenotype. The direct application of such decellularized matrices (DMs) to 3D substrates is problematic, as transport issues influence the homogeneous deposition, decellularization, and modification of DM surface coatings. In an attempt to address this shortcoming, we hypothesized that DMs deposited by human mesenchymal stem cells (MSCs) could be transferred to the surface of polymeric scaffolds while maintaining their capacity to direct cell fate. The ability of the transferred DM (tDM)-coated scaffolds to enhance the osteogenic differentiation of undifferentiated and osteogenically induced MSCs under osteogenic conditions in vitro was confirmed. tDM-coated scaffolds increased MSC expression of osteogenic marker genes (BGLAP, IBSP) and intracellular alkaline phosphatase production. In addition, undifferentiated MSCs deposited significantly more calcium when seeded onto tDM-coated scaffolds compared with control scaffolds. MSC-seeded tDM-coated scaffolds subcutaneously implanted in nude rats displayed significantly higher blood vessel density after 2 weeks compared with cells on uncoated scaffolds, but we did not observe significant differences in mineral deposition after 8 weeks. These data demonstrate that DM-coatings produced in 2D culture can be successfully transferred to 3D substrates and retain their capacity to modulate cell phenotype.

Electrochemical and wear behavior of niobium-vanadium carbide coatings produced on AISI H13 tool steel through thermo-reactive deposition/diffusion

International Nuclear Information System (INIS)

Castillejo Nieto, Fabio Enrique; Olaya Flores, Jhon Jairo; Alfonso Orjuela, Jose Edgar

2016-01-01

We deposited of niobium-vanadium carbide coatings on tool steel AISI H13 using the thermo-reactive substrates deposition/diffusion (TRD) technique. The carbides were obtained using salt baths composed of molten borax, ferroniobium, vanadium and aluminum, by heating this mixture at 1020°C for 4 hours. The coatings were characterized morphologically via electron microscopy scanning (SEM), the chemical surface composition was determined through X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray spectroscopy (EDX); the crystal structure was analyzed using x-ray diffraction (XRD), the mechanical properties of the coatings were evaluated using nano-indentation, The tribological properties of the coatings obtained were determined using a Pin-on-disk tribometer and the electrochemical behavior was studied through potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS). The results showed that the hardness of the coated steel increased four times with respect to uncoated steel, and the electrochemical test established that the corrosion current is lower by one order of magnitude for coated steel

ASSESSMENT OF STRIPPABLE COATINGS FOR DEACTIVATION AND DECOMMISSIONING

International Nuclear Information System (INIS)

Ebadian, M.A.

1999-01-01

Strippable coatings are polymer mixtures, such as water-based organic polymers, that are applied to a surface by paintbrush, roller, or spray applicator. As the polymer reacts, it attracts, absorbs, and chemically binds the contaminants; then, during the curing process, it mechanically locks the contaminants into the polymer matrix. Incorporating fiber reinforcement (such as a cotton scrim) into the coating may enhance the strength of these coatings. Once the coating dries, it can be stripped manually from the surface, In the case of auto-release coatings, the mixture cracks, flakes, and is collected by vacuuming. The surface properties of these coatings may be modified by applying a thin top coat (e.g., polyvinyl alcohol), which may provide a smoother, less permeable surface that would become less severely contaminated. In such a duplex, the thicker basis layer provides the required mechanical properties (e.g., strength and abrasion resistance), while the top layer provides protection from contamination. Once the strippable coating is removed, the loose surface contamination is removed with the coating, producing a dry, hard, non-airborne waste product. The use of strippable coatings during D and D operations has proved a viable option. These coatings can be used in the following three functions: As a protective coating, when applied to an uncontaminated surface in an area where contamination is present, so that on its removal the surface remains uncontaminated; As a decontamination agent, when applied to a contaminated surface, so that on its removal a significant decontamination of loose particulate activity is achieved; and As a fixative or tie-down coating, when applied to a contaminated surface, so that any loose contamination is tied down, thus preventing the spread of contamination during subsequent handling

Corrosion-electrochemical characteristics of oxide-carbide and oxide-nitride coatings formed by electrolytic plasma

International Nuclear Information System (INIS)

Tomashov, N.D.; Chukalovskaya, T.V.; Medova, I.L.; Duradzhi, V.N.; Plavnik, G.M.

1990-01-01

The composition, structure, microhardness and corrosion-electrochemical properties of oxide-carbide and oxide-nitride coatings on titanium in 5n H 2 SO 4 , 50 deg, produced by the method of chemical-heat treatment in electrolytic plasma, containing saturation components of nitrogen and carbon, were investigated. It is shown that the coatings produced have increased hardness, possess high corrosion resistance in sulfuric acid solution at increased temperature, as to their electrochemcial behaviour they are similar to titanium carbide and nitride respectively. It is shown that high corrosion resistance is ensured by electrochemical mechanism of the oxide-carbide and oxide-nitride coating protection

Extraction of pectin from passion fruit rind (Passiflora edulis var. flavicarpa Degener) for edible coating

Science.gov (United States)

Inayati, Puspita, Rifka Intan; Fajrin, Vika Latifiana

2018-02-01

One of fruit preservation method is by applying the edible coating. Rind of passion fruit (Passiflora edulis var. flavicarpa Degener), which is kind of waste, can be utilized as edible coating through pectin extraction process. The purposes of this work were to determine the suitable solvent for the pectin extraction and techniques for applying the produced edible coating on strawberry, to produce edible coating from the pectin, and the test the performance of the edible coating which was applied to strawberries. Pectin from passion fruit rind was collected through conventional extraction method using two types of solvent, i.e. acetic acid solution and hydrochloric acid solution with concentration of 0.01 N, 0.015 N, 0.02 N, 0.025 N, and 0.03 N. The results showed that chloric acid solution was more suitable for the pectin extraction from passion fruit. Maximum yield of 30.78% was obtained at hydrochloric acid concentration of 0.02 N. Obtained pectin from the extraction was then processed into the edible coating by adding plasticizers and calcium chloride dihydrate. Storability of the coated strawberry was observed to measure the performance of the edible coating

Antireflection coating on InP for semiconductor detectors

International Nuclear Information System (INIS)

Hantehzadeh, M.R.; Ghoranneviss, M.; Sari, A.H.; Sahlani, F.; Shokuhi, A.; Shariati, M.

2006-01-01

Aluminum nitride thin film by RF magnetron sputtering is used to produce antireflection coating on InP. The index of refection variation of aluminum nitride for different thickness at different wavelength in the range of 400 to 1500 nm is investigated using reflection spectroscopy. Subsequent Ar+ ion implantation at 30 keV with different doses on these coated layers has been performed. The morphology of aluminum nitride after ion implantation is characterized using atomic force microscopy AFM

Antireflection coating on InP for semiconductor detectors

Energy Technology Data Exchange (ETDEWEB)

Hantehzadeh, M.R. [Plasma Physics Research Center, Science and Research Campus of Islamic Azad University, Tehran (Iran, Islamic Republic of)]. E-mail: hanteh@sr.iau.ac.ir; Ghoranneviss, M. [Plasma Physics Research Center, Science and Research Campus of Islamic Azad University, Tehran (Iran, Islamic Republic of); Sari, A.H. [Plasma Physics Research Center, Science and Research Campus of Islamic Azad University, Tehran (Iran, Islamic Republic of); Sahlani, F. [Plasma Physics Research Center, Science and Research Campus of Islamic Azad University, Tehran (Iran, Islamic Republic of); Shokuhi, A. [Plasma Physics Research Center, Science and Research Campus of Islamic Azad University, Tehran (Iran, Islamic Republic of); Shariati, M. [Plasma Physics Research Center, Science and Research Campus of Islamic Azad University, Tehran (Iran, Islamic Republic of)

2006-10-25

Aluminum nitride thin film by RF magnetron sputtering is used to produce antireflection coating on InP. The index of refection variation of aluminum nitride for different thickness at different wavelength in the range of 400 to 1500 nm is investigated using reflection spectroscopy. Subsequent Ar+ ion implantation at 30 keV with different doses on these coated layers has been performed. The morphology of aluminum nitride after ion implantation is characterized using atomic force microscopy AFM.

Monolayer nanoparticle-covered liquid marbles derived from a sol-gel coating

Science.gov (United States)

Li, Xiaoguang; Wang, Yiqi; Huang, Junchao; Yang, Yao; Wang, Renxian; Geng, Xingguo; Zang, Duyang

2017-12-01

A sol-gel coating consisting of hydrophobic SiO2 nanoparticles (NPs) was used to produce monolayer NP-covered (mNPc) liquid marbles. The simplest approach was rolling a droplet on this coating, and an identifiable signet allowed determination of the coverage ratio of the resulting liquid marble. Alternatively, the particles were squeezed onto a droplet surface with two such coatings, generating surface buckling from interfacial NP jamming, and then a liquid marble was produced via a jamming-relief process in which water was added into the buckled droplet. This process revealed an ˜7% reduction in particle distance after interfacial jamming. The mNPc liquid marbles obtained by the two methods were transparent with smooth profiles, as naked droplets, and could be advantageously used in fundamental and applied researches for their unique functions.

Evolution of the Automotive Body Coating Process—A Review

Directory of Open Access Journals (Sweden)

Nelson K. Akafuah

2016-06-01

Full Text Available Automotive coatings and the processes used to coat automobile surfaces exemplify the avant-garde of technologies that are capable of producing durable surfaces, exceeding customers’ expectations of appearance, maximizing efficiency, and meeting environmental regulations. These accomplishments are rooted in 100 years of experience, trial-and-error approaches, technique and technology advancements, and theoretical assessments. Because of advancements directed at understanding the how, why, when, and where of automobile coatings, the progress in controlling droplets and their deposition attributes, and the development of new technologies and paint chemistries, a comprehensive and up-to-date review of automobile coatings and coating technologies was considered to be of value to industrial practitioners and researchers. Overall, the critical performance factors driving the development and use of advanced automotive coatings and coating technologies are (a aesthetic characteristics; (b corrosion protection; (c mass production; (d cost and environmental requirements; and (e appearance and durability. Although the relative importance of each of these factors is debatable, the perfection of any one at the expense of another would be unacceptable. Hence, new developments in automotive coatings are described and discussed in the following review, and then related to improvements in production technologies and paints. Modern automotive coating procedures are also discussed in detail. Finally, an extrapolation into the future of automotive coating is offered with a view of the developments and technologies needed for an increasingly efficient and more sustainable coatings industry.

Novel surface coating materials for endodontic dental implant

International Nuclear Information System (INIS)

Fathi, M.H.; Mortazavi, V.; Moosavi, S.B.

2003-01-01

The aim of this study was to design and produce novel coating materials in order to obtain two goals including; improvement of the corrosion behavior of metallic dental endodontic implant and the bone osteointegration simultaneously. Stainless steel 316L (SS) was used as a metallic substrate and a novel Hydroxyapatite/Titanium (HA/Ti) composite coating was prepared on it. Structural characterization techniques including XRD, SEM and EDX were utilized to investigate the microstructure and morphology of the coating. Electrochemical tests were performed in physiological solutions in order to determine and compare the corrosion behavior of the coated and uncoated specimens as an indication of biocompatibility. Two types of endodontic implants including; SS with and without (HA/Ti) composite coating were prepared and subsequently implanted in the mandibular canine of 20 cats after completion of root canal treatment and osseous preparation. After a healing period of 4 months, osteointegration evaluation and histopathological interpretation was carried out using SEM and optical microscopy. Results indicate that the novel HA/Ti composite coating improves the corrosion behavior and biocompatibility of SS endodontic dental implant. The clinical evaluation (in vivo test) results showed that there was significant difference in osteointegration between coated and uncoated endodontic dental implants and average bone osteointegration of coated implants were more than uncoated implants. The histopathological results and bone tissue response to the coated implants was acceptable and it was concluded that HA/Ti composite coated SS could be used as well as an endodontic dental implant. (author)

Nanoparticle/Polymer Nanocomposite Bond Coat or Coating

Science.gov (United States)

Miller, Sandi G.

2011-01-01

This innovation addresses the problem of coatings (meant to reduce gas permeation) applied to polymer matrix composites spalling off in service due to incompatibility with the polymer matrix. A bond coat/coating has been created that uses chemically functionalized nanoparticles (either clay or graphene) to create a barrier film that bonds well to the matrix resin, and provides an outstanding barrier to gas permeation. There is interest in applying clay nanoparticles as a coating/bond coat to a polymer matrix composite. Often, nanoclays are chemically functionalized with an organic compound intended to facilitate dispersion of the clay in a matrix. That organic modifier generally degrades at the processing temperature of many high-temperature polymers, rendering the clay useless as a nano-additive to high-temperature polymers. However, this innovation includes the use of organic compounds compatible with hightemperature polymer matrix, and is suitable for nanoclay functionalization, the preparation of that clay into a coating/bondcoat for high-temperature polymers, the use of the clay as a coating for composites that do not have a hightemperature requirement, and a comparable approach to the preparation of graphene coatings/bond coats for polymer matrix composites.

The Insulation of Copper Wire by the Electrostatic Coating Process.

Science.gov (United States)

1983-06-30

Caster full production lines produce more uniform coating thicknesses. -18- U AM NC. IO C FWIO~k TX3M ..... ....... Z . A A I~ ~ 15X 7-., r - ’ r 15X... modification to meet specific usage requirements. t * -68- 482 5 APPENDIX CLIQUINITE’ COATING PRODU(:TS LIQUINITEE-COATING POWDERS FEP (Fluorinated Ethylene...Loss from Dissipation Factor (60 Hz-2xl0 9Hz) 0.2-1.2001 Revolving Disc, mg (60 Hz -2 x iO0 Hz) *CS 17 Wheel . 100 cycles 2.2 Surface Resistivity (250

High efficiency turbine blade coatings

Energy Technology Data Exchange (ETDEWEB)

Youchison, Dennis L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Gallis, Michail A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2014-06-01

The development of advanced thermal barrier coatings (TBCs) of yttria stabilized zirconia (YSZ) that exhibit lower thermal conductivity through better control of electron beam - physical vapor deposition (EB-PVD) processing is of prime interest to both the aerospace and power industries. This report summarizes the work performed under a two-year Lab-Directed Research and Development (LDRD) project (38664) to produce lower thermal conductivity, graded-layer thermal barrier coatings for turbine blades in an effort to increase the efficiency of high temperature gas turbines. This project was sponsored by the Nuclear Fuel Cycle Investment Area. Therefore, particular importance was given to the processing of the large blades required for industrial gas turbines proposed for use in the Brayton cycle of nuclear plants powered by high temperature gas-cooled reactors (HTGRs). During this modest (~1 full-time equivalent (FTE)) project, the processing technology was developed to create graded TBCs by coupling ion beam-assisted deposition (IBAD) with substrate pivoting in the alumina-YSZ system. The Electron Beam - 1200 kW (EB-1200) PVD system was used to deposit a variety of TBC coatings with micron layered microstructures and reduced thermal conductivity below 1.5 W/m.K. The use of IBAD produced fully stoichiometric coatings at a reduced substrate temperature of 600°C and a reduced oxygen background pressure of 0.1 Pa. IBAD was also used to successfully demonstrate the transitioning of amorphous PVD-deposited alumina to the -phase alumina required as an oxygen diffusion barrier and for good adhesion to the substrate Ni₂Al₃ bondcoat. This process replaces the time consuming thermally grown oxide formation required before the YSZ deposition. In addition to the process technology, Direct Simulation Monte Carlo plume modeling and spectroscopic characterization of the PVD plumes were performed. The project consisted of five tasks. These included the

Cyclic Oxidation and Hot Corrosion of NiCrY-Coated Disk Superalloys

Science.gov (United States)

Gabb, Timothy P.; Miller, Robert A.; Sudbrack, Chantal K.; Draper, Susan L.; Nesbitt, James A.; Rogers, Richard B.; Telesman, Ignacy; Ngo, Vanda; Healy, Jonathan

2016-01-01

Powder metallurgy disk superalloys have been designed for higher engine operating temperatures through improvement of their strength and creep resistance. Yet, increasing disk application temperatures to 704 degrees Centigrade and higher could enhance oxidation and activate hot corrosion in harmful environments. Protective coatings could be necessary to mitigate such attack. Cylindrical coated specimens of disk superalloys LSHR and ME3 were subjected to thermal cycling to produce cyclic oxidation in air at a maximum temperature of 760 degrees Centigrade. The effects of substrate roughness and coating thickness on coating integrity after cyclic oxidation were considered. Selected coated samples that had cyclic oxidation were then subjected to accelerated hot corrosion tests. This cyclic oxidation did not impair the coating's resistance to subsequent hot corrosion pitting attack.

New sol–gel refractory coatings on chemically-bonded sand cores for foundry applications to improve casting surface quality

DEFF Research Database (Denmark)

Nwaogu, Ugochukwu Chibuzoh; Poulsen, T.; Stage, R.K.

2011-01-01

Foundry refractory coatings protect bonded sand cores and moulds from producing defective castings during the casting process by providing a barrier between the core and the liquid metal. In this study, new sol–gel refractory coating on phenolic urethane cold box (PUCB) core was examined. The coa......Foundry refractory coatings protect bonded sand cores and moulds from producing defective castings during the casting process by providing a barrier between the core and the liquid metal. In this study, new sol–gel refractory coating on phenolic urethane cold box (PUCB) core was examined......–gel coated cores have better surface quality than those from uncoated cores and comparable surface quality with the commercial coatings. Therefore, the new sol–gel coating has a potential application in the foundry industry for improving the surface finish of castings thereby reducing the cost of fettling...

Procedure for coating articles with pyrolytic carbon

International Nuclear Information System (INIS)

Adams, C.C.; Allen, C.L.; Besenbruch, G.E.A.

1976-01-01

A method to coat articles with pyrolytic carbon is described which is particularly suitable for small nuclear fuel particles as one obtains a very homogeneous layer. The pyrolytic carbon is produced according to the invention by decomposing a hydrocarbon gas mixture composed of an inert gas share (20-65 Vol%) and a mixture of acetylene and propylene. It is favourable to have the hydrocarbon mixture contain between 50 and 55 Vol% acetylene. Variations on the known procedure are given. The coating of spherical thorium dioxide particles is mentioned as an example. (UWI) [de

Potential assisted fabrication of metal-ceramic composite coatings

International Nuclear Information System (INIS)

Knote, A.; Schindler, U.; Krueger, H.G.; Kern, H.

2003-01-01

A possibility to produce uniform metal-ceramic composite coatings with a high content of ceramic particles up to 60 vol.% will be presented in this study. This method includes a combination of electrophoretic deposition and electrolytic deposition by several steps. A yttria-stabilized zirconia coating (Tosoh TZ-8Y) was first electrophoretically deposited on a ferritic steel plate and then sintered by 1100 C to an open porous layer. In the next step nickel was electrodeposited into the pores of the layer. By a final annealing step it was possible to improve the bonding of the composit coating on the substrate by diffusion of the metal components. (Abstract Copyright [2003], Wiley Periodicals, Inc.) [de

YBCO coated conductors by reactive thermal co-evaporation

Energy Technology Data Exchange (ETDEWEB)

Schmatz, U.; Hoffmann, Ch.; Bauer, M.; Metzger, R.; Berberich, P.; Kinder, H. [Technische Univ. Muenchen, Garching (Germany). Physik-Department

2001-12-01

Coated tape conductors of YBCO require a deposition process allowing to obtain a high volume growth rate in order to produce long lengths of tape in a reasonable amount of time. We present our tape coating system where 15 parallel loops of travelling tape of 1 cm width can be coated simultaneously by reactive thermal co-evaporation. For high critical current densities, in-plane alignment of the YBCO film is necessary. Inclined substrate deposition (ISD) is a technique that allows to deposit in-plane oriented buffer layers suitable for YBCO growth at high deposition rates. We present results obtained for YBCO films grown on MgO-ISD buffer layers deposited by e-gun evaporation onto metallic tape substrates. (orig.)

Sea water Corrosion of Nickel based Plasma Spray Coating

Science.gov (United States)

Parida, M.; Nanda, S. P.; Bhuyan, S. K.; Mishra, S. C.

2018-03-01

Different types of erosion resistant coatings are applied/deposited on aero components, depending on the operating/working temperatures. Nickel based coating are applied on the air craft (compressor) components, which can sustain up to working temperature of 650°C. In the present investigation, to improve the compatibility between substrate (i.e. the machine component) and the top coat, application of bond coat is there. The application of Nickel based coating by thermal plasma spray technique has proven to be a satisfactory means of producing acceptable sealing surface with excellent abradability. Before the corrosion study, coated sample is subjected to hardness, thickness and porosity testing. Hence the result is being evaluated. The corrosion behavior of coating was studied by sea water immersion with a time period of 16 weeks. It is observed that, up to 9 weeks increase in weight of coating occurs in a sharp trend and then takes a decreasing trend. The weight gain of the samples has varied from 37.23% (with one week immersion in sea water) to a maximum of about 64.36% for six weeks immersion. Coating morphology and composition analysis of the coatings are studied using SEM and EDS. This behavior shows adsorption/deposition of the foreign particles with polygonal shape on the coating surface by sea water interaction. Foreign particles with polygonal shape deposited on the coating and with increase in immersion/treatment time, washing out of the deposited materials starts, which reflects the decreasing trend of weight gain of the specimen.

Beneficial effects of laser irradiation on the deposition process of diamond/Ni60 composite coating with cold spray

Energy Technology Data Exchange (ETDEWEB)

Yao, Jianhua, E-mail: laser@zjut.edu.cn; Yang, Lijing; Li, Bo; Li, Zhihong

2015-03-01

Graphical abstract: - Highlights: • The hard Ni-based alloy powder as matrix in diamond composite coating was studied. • The influence of laser on diamond distribution of composite coating was analyzed. • The graphitization of diamond was prohibited in supersonic laser deposition process. • The abrasion mechanisms of diamond/Ni60 composite coating were discussed. - Abstract: Although cold spray process has many unique advantages over other coating techniques, it has difficulties in depositing hard materials. This article presents a study in the beneficial effects of laser irradiation on the fabrication process of diamond/Ni60 composite coating using cold spray. The focus of this research is on the comparison between the composite coatings produced with laser cladding (LC) and with supersonic laser deposition (SLD), with respect to diamond graphitization and tribological properties, thus to demonstrate the beneficial effects of laser irradiation on the cold spray process. The influence of deposition temperature on the coating characteristics, such as deposition efficiency, diamond volume fraction, microstructure and phase is also investigated. The tribological properties of the diamond/Ni60 composite coating produced with SLD are determined using a pin-on-disc tribometer, along with the diamond/Ni60 coating produced using LC with the optimal process parameters for comparison. The experimental results show that with the assistance of laser irradiation, diamond/Ni60 composite coating can be successfully deposited using cold spray; the obtained coating is superior to that processed with LC, because SLD can suppress the graphitization of the diamond particles. The diamond/Ni60 composite coating fabricated with SLD has much better tribological properties than the LC coating.

Preparation and tribological properties of self-lubricating TiO2/graphite composite coating on Ti6Al4V alloy

International Nuclear Information System (INIS)

Mu, Ming; Zhou, Xinjian; Xiao, Qian; Liang, Jun; Huo, Xiaodi

2012-01-01

Highlights: ► A TiO 2 /graphite composite coating is produced on Ti alloy by one-step PEO process. ► The TiO 2 /graphite composite coating exhibits excellent self-lubricating behavior. ► The self-lubricating composite coating improves the wear resistance by comparison to the conventional PEO coating. - Abstract: One-step plasma electrolytic oxidation (PEO) process in a graphite-dispersed phosphate electrolyte was used to prepare a graphite-containing oxide composite coating on Ti6Al4V alloy. The composition and microstructure of the oxide coatings produced in the phosphate electrolytes with and without addition of graphite were analyzed by X-ray diffractometer (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The tribological properties of the uncoated Ti6Al4V alloy and oxide coatings were evaluated using a reciprocating ball-on-disk tribometer. Results showed that the graphite-containing oxide composite coating can be successfully produced on Ti6Al4V alloy in the graphite-dispersed phosphate electrolyte using PEO process. The graphite-containing oxide composite coating registered much lower friction coefficient and wear rate than the uncoated Ti6Al4V alloy and the oxide coating without graphite under dry sliding condition, exhibiting excellent self-lubricating property.

Self-assembled hemocompatible coating on poly (vinyl chloride) surface

Energy Technology Data Exchange (ETDEWEB)

Zha Zhengbao; Ma Yan; Yue Xiuli; Liu Meng [Nanobiotechnology Division, State Key Laboratory of Urban Water Resources and Environment, School of Sciences, Harbin Institute of Technology, Harbin 150001 (China); Dai Zhifei, E-mail: zhifei.dai@hit.edu.cn [Nanobiotechnology Division, State Key Laboratory of Urban Water Resources and Environment, School of Sciences, Harbin Institute of Technology, Harbin 150001 (China)

2009-11-15

A stable hemocompatible coating was fabricated by consecutive alternating adsorption of iron (III) and two kinds of polysaccharides, heparin (Hep) and dextran sulfate (DS), onto poly (vinyl chloride) (PVC) surfaces via electrostatic interaction. The fluctuation of contact angles with the alternative deposition of iron (III) and polysaccharides verified the progressive buildup of the mulitilayer coating onto the PVC surface. Atomic force microscopy (AFM) analysis revealed that the PVC surfaces were completely masked by iron-polysaccharides multilayer coatings. The activated partial thromboplastin time (APTT) assay showed that both Hep/Fe{sup 3+}/Hep and DS/Fe{sup 3+}/Hep coated PVC were less thrombogenic than the uncoated one. Chromogenic assay for heparin activity proved definitively that the inhibition of locally produced thrombin was ascribed to the thromboresistance of the surface-bound heparin. Compared with the unmodified PVC surfaces, iron-polysaccharide multilayer coating presented a drastically reduced adhesion in vitro of platelets, polymorphonuclear neutrophil leukocytes (PMN) and peripheral blood mononuclear cells (PBMC). Interestingly, the DS/Fe{sup 3+}/Hep coating was found to exhibit higher hydrophilicity and stability, hence lower non-specific protein adsorption in comparison with Hep/Fe{sup 3+}/Hep coating due to the incorporation of dextran sulfate into the multilayer coating.

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.)

Osteoblast interaction with DLC-coated Si substrates.

Science.gov (United States)

Chai, Feng; Mathis, Nicolas; Blanchemain, Nicolas; Meunier, Cathy; Hildebrand, Hartmut F

2008-09-01

Diamond-like carbon (DLC) coating is a convenient means of modifying material surfaces that are sensitive to wear, such as titanium and silica substrates. This work aims to evaluate the osteoblast-like cells' response to DLC-coated Si (Si-DLC), which was treated under different conditions. DLC and deuterated DLC films were deposited by plasma-enhanced chemical vapor deposition to obtain a 200-nm-thick layer on all the samples. Three types of precursor gas were applied for deposition: pure methane (CH(4)), pure deuterated methane (CD(4)) and their half/half mixture. All surface treatments were performed under two different self-bias voltages (V(sb)): -400 and -600V. The modified surfaces were characterized by X-ray photoelectron spectroscopy, Raman spectroscopy, Rutherford backscattering spectroscopy, elastic recoil detection analysis, X-ray reflectometry and the sessile-drop method. MC3T3-E1 osteoblasts were cultured on the Si-DLC wafers for 3 and 6 days. Biological tests to measure cell proliferation, cell vitality, cell morphology and cell adhesion were performed. All DLC coatings produced a slightly more hydrophobic state than non-treated Si. Certain types of amorphous DLC coating, such as the surface treated under the V(sb) of -600V in pure methane (600CH(4)) or in pure deuterated methane (600CD(4)), offered a significantly higher cell proliferation rate to Si substrate. Scanning electron microscopy observations confirmed that the optimal cell adhesion behavior, among all the treated surfaces, occurred on the surface of the 600CH(4) and 600CD(4) groups, which showed increased amounts of filopodia and microvilli to enhance cell-environment exchange. In conclusion, DLC coating on Si could produce better surface stability and improved cellular responses.

Roll-to-roll vacuum deposition of barrier coatings

CERN Document Server

Bishop, Charles A

2015-01-01

It is intended that the book will be a practical guide to provide any reader with the basic information to help them understand what is necessary in order to produce a good barrier coated web or to improve the quality of any existing barrier product. After providing an introduction, where the terminology is outlined and some of the science is given (keeping the mathematics to a minimum), including barrier testing methods, the vacuum deposition process will be described. In theory a thin layer of metal or glass-like material should be enough to convert any polymer film into a perfect barrier material. The reality is that all barrier coatings have their performance limited by the defects in the coating. This book looks at the whole process from the source materials through to the post deposition handling of the coated material. This holistic view of the vacuum coating process provides a description of the common sources of defects and includes the possible methods of limiting the defects. This enables readers...

Preliminary coating design and coating developments for ATHENA

DEFF Research Database (Denmark)

Jakobsen, Anders Clemen; Ferreira, Desiree Della Monica; Christensen, Finn Erland

2011-01-01

We present initial novel coating design for ATHENA. We make use of both simple bilayer coatings of Ir and B4C and more complex constant period multilayer coatings to enhance the effective area and cover the energy range from 0.1 to 10 keV. We also present the coating technology used...... for these designs and present test results from coatings....

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.

Effects of mesquite gum-candelilla wax based edible coatings on the quality of guava fruit (Psidium guajava L.)

Science.gov (United States)

Tomás, S. A.; Bosquez-Molina, E.; Stolik, S.; Sánchez, F.

2005-06-01

The ability of composite edible coatings to preserve the quality of guava fruit (Psidium guajava L.) at 20ºC was studied for a period of 15 days. The edible coatings were formulated with candelilla wax blended with white mineral oil as the lipid phase and mesquite gum as the structural material. The use of edible coatings prolonged the shelf life of treated fruits by retarding ethylene emission and enhancing texture as compared to control samples. At the sixth day, the ethylene produced by the control samples was fivefold higher than the ethylene produced by the coated samples. In addition, the physiological weight loss of coated fruits was nearly 30% lower than the control samples.

Cellulose nanofibers use in coated paper

Science.gov (United States)

Richmond, Finley

Cellulose Nanofibers (CNF) are materials that can be obtained by the mechanical breakdown of natural fibers. CNF have the potential to be produced at low cost in a paper mill and may provide novel properties to paper, paper coatings, paints, or other products. However, suspensions have a complex rheology even at low solid contents. To be able to coat, pump, or mix CNF at moderate solids, it is critical to understand the rheology of these suspensions and how they flow in process equipment; current papers only report the rheology up to 6% solids. Few publications are available that describe the coating of CNF onto paper or the use of CNF as an additive into a paper coating. The rheology of CNF suspensions and coatings that contain CNF were characterized with parallel-disk geometry in a controlled stress rheometer. The steady shear viscosity, the complex viscosity, the storage modulus, and the yield stress were determined for the range of solids or concentrations (2.5-10.5%). CNF were coated onto paper with a laboratory rod coater, a size press and a high speed cylindrical laboratory coater (CLC). For each case, the coat weights were measures and the properties of the papers were characterized. CNF water base suspension was found to be a shear thinning with a power law index of around 0.1. Oscillatory tests showed a linear viscoelastic region at low strains and significant storage and loss moduli even at low solids. The Cox Merz rule does not hold for CNF suspensions or coating formulations that contain CNF with complex viscosities that are about 100 times larger than the steady shear viscosities. Paper coating formulations that contain CNF were found to have viscosities and storage and loss moduli that are over ten times larger than coatings that contain starch at similar solids. CNF suspensions were coated on papers with low amount transferred on paper either at high solids or high nip loadings. The amount transferred appears to be controlled by an interaction of

A novel phosphorylcholine-coated contact lens for extended wear use.

Science.gov (United States)

Court, J L; Redman, R P; Wang, J H; Leppard, S W; Obyrne, V J; Small, S A; Lewis, A L; Jones, S A; Stratford, P W

2001-12-01

The preparation and characterisation of a new phosphorylcholine (PC)-coated silicone hydrogel contact lens for use in extended wear is described. The Michael-type addition of amines to acrylates forms the basis of the synthesis of a novel silicone-based macromer with hydrophilic functionality. It is demonstrated that this macromer can be combined with other silicone-based monomers, hydrophilic monomers and crosslinker to produce a contact lenses formulation. Examples of lenses with water contents of 33% and 46% are illustrated and their properties compared to other commercially available lenses. Materials with comparatively low modulus (2-4MPa) with excellent elongation to break (>200%) can be obtained using this technology. In addition to the mechanical aspects. both the oxygen and solute permeabilities of the material can be controlled by the hydrophilic: hydrophobic monomer balance in the formulation. to obtain materials with attributes suitable for extended wear use. The PC coating is achieved by means of an in-mould coating (IMC) technique that produces a uniform and stable surface as determined by staining and XPS. The coating imparts both improved lens wettability (advancing contact angle of approximately 50 with virtually no hysteresis) and lower protein adsorption relative to the uncoated lens.

Electrocurtain coating process for coating solar mirrors

Science.gov (United States)

Kabagambe, Benjamin; Boyd, Donald W.; Buchanan, Michael J.; Kelly, Patrick; Kutilek, Luke A.; McCamy, James W.; McPheron, Douglas A.; Orosz, Gary R.; Limbacher, Raymond D.

2013-10-15

An electrically conductive protective coating or film is provided over the surface of a reflective coating of a solar mirror by flowing or directing a cation containing liquid and an anion containing liquid onto the conductive surface. The cation and the anion containing liquids are spaced from, and preferably out of contact with one another on the surface of the reflective coating as an electric current is moved through the anion containing liquid, the conductive surface between the liquids and the cation containing liquid to coat the conductive surface with the electrically conductive coating.

Coatings for use on the limiters of a fusion reactor

International Nuclear Information System (INIS)

Scott, K.T.; Coad, J.P.; Cross, A.G.; Ayres, C.; Warrington, P.

1982-02-01

The suitability of plasma spraying, sputter ion plating (SIP) and plasma activated vapour deposition (PAVD) to deposit metal and ceramic coatings onto copper, Inconel and copper explosively clad with refractory metals for potential use in limiter devices was investigated. The coatings produced were subjected to pulse heating by a plasma torch or by RF induction to assess their thermal shock resistance. Hydrogen retention was measured at various temperatures in coatings on Inconel subjected to deuterium ion bombardment. Scanning electron microscopy was carried out on fracture surfaces exposed when specimens were bent to test coating adhesion and on front faces of irradiated coatings. Plasma sprayed coatings were easily applied to any substrate but only TiC and TiN could be deposited by SIP onto copper while the PAVD of SiC was restricted to Inconel or clad copper. Thermal expansion mismatch between the coatings and copper were responsible for most of the failures. Evidence of the migration of substrate elements to the coating surface during heating was observed. Despite some change in visual appearance close examination revealed that only TiC was significantly damaged by deuteron irradiation. (author)

Coatings for minimally processed fruits and vegetables

Science.gov (United States)

Fresh-cut fruit and vegetables are gaining increasing popularity and market share. Techniques to enhance stability of fresh cut produce are reviewed. Among these techniques, edibles coatings can provide protection against dehydration, microbial decay and decrease events related to physiological sene...

Coating of waste containing ceramic granules

International Nuclear Information System (INIS)

Neumann, W.; Kofler, O.

1979-01-01

Simulated high-level waste granules produced by fluidized-bed calcination were overcoated by chemical vapor deposition (CVD) with pyrocarbon and nickel in laboratory-scale experiments. Successful development enables pyrocrbon deposition at temperatures of 600 to 800 0 K. The coated granules have excellent properties for long-term waste storage

The shaping of zinc coating on surface steels and ductile iron casting

Directory of Open Access Journals (Sweden)

D. Kopyciński

2010-01-01

Full Text Available The studies aimed at an analysis of the formation and growth kinetics of zinc coating on reactive silicon-killed steels in a zinc bath. The growth kinetics of the produced zinc coatings was evaluated basing on the power-law growth equation. As regards galvanizing of the surface of products, investigation was done for various steel grades and ductile iron (DI taking into account the quality and thickness of coating. It has been proved that the chemical constitution of basis significantly influences the kinetics of growth of the individual phases in a zinc coating. This relationship was evaluated basing on the, so called, silicon and phosphorus equivalent ESi,P and coating thickness dependences were obtained.

Conductive Carbon Coatings for Electrode Materials

International Nuclear Information System (INIS)

Doeff, Marca M.; Kostecki, Robert; Wilcox, James; Lau, Grace

2007-01-01

A simple method for optimizing the carbon coatings on non-conductive battery cathode material powders has been developed at Lawrence Berkeley National Laboratory. The enhancement of the electronic conductivity of carbon coating enables minimization of the amount of carbon in the composites, allowing improvements in battery rate capability without compromising energy density. The invention is applicable to LiFePO 4 and other cathode materials used in lithium ion or lithium metal batteries for high power applications such as power tools and hybrid or plug-in hybrid electric vehicles. The market for lithium ion batteries in consumer applications is currently $5 billion/year. Additionally, lithium ion battery sales for vehicular applications are projected to capture 5% of the hybrid and electric vehicle market by 2010, and 36% by 2015 (http://www.greencarcongress.com). LiFePO 4 suffers from low intrinsic rate capability, which has been ascribed to the low electronic conductivity (10 -9 S cm -1 ). One of the most promising approaches to overcome this problem is the addition of conductive carbon. Co-synthesis methods are generally the most practical route for carbon coating particles. At the relatively low temperatures ( 4 , however, only poorly conductive disordered carbons are produced from organic precursors. Thus, the carbon content has to be high to produce the desired enhancement in rate capability, which decreases the cathode energy density

SAPO-34 coated adsorbent heat exchanger for adsorption chillers

International Nuclear Information System (INIS)

Freni, Angelo; Bonaccorsi, Lucio; Calabrese, Luigi; Caprì, Angela; Frazzica, Andrea; Sapienza, Alessio

2015-01-01

In this work, adsorbent coatings on aluminum surfaces were prepared by dip-coating method starting from a water suspension of SAPO-34 zeolite and a silane-based binder. Silane-zeolite coatings morphology and surface coverage grade were evaluated by scanning electron microscopy. Adhesive and mechanical properties were evaluated by peel, pull-off, impact and micro-hardness tests, confirming the good interaction between metal substrate, binder and zeolite. Adsorption equilibrium and kinetics of water vapour adsorption on the adsorbent coating were studied in the range T = 30–150 °C and pH 2 O = 11 mbar using a CAHN 2000 thermo-balance. It was found that, in the investigated conditions, the organic binder doesn't affect the water adsorption capacity and adsorption kinetics of the original SAPO-34 zeolite. Subsequently, the zeolite coating was applied on a finned flat-tubes aluminum heat exchanger realizing a full-scale AdHEx with an uniform adsorbent coating 0.1 mm thick and a metal/adsorbent mass ratio = 6. The cooling capacity of the realized coated AdHEx was measured by a lab-scale adsorption chiller under realistic operating conditions for air conditioning applications. The coated AdHEx produced up to 675 W/kg ads specific cooling power with a cycle time of 5 min. Adsorption stability of the coated adsorber subjected to 600 sorption cycles was successfully verified. - Highlights: • Adsorbent coatings on aluminum surfaces were prepared by dip-coating method. • Silane-zeolite coatings morphology, and mechanical properties were studied. • The zeolite coating was applied on a finned flat-tubes aluminum heat exchanger. • The coated AdHEx was tested in a lab scale adsorption chiller

Physically vapor deposited coatings on tools: performance and wear phenomena

International Nuclear Information System (INIS)

Koenig, W.; Fritsch, R.; Kammermeier, D.

1991-01-01

Coatings produced by physical vapor deposition (PVD) enhance the performance of tools for a broad variety of production processes. In addition to TiN, nowadays (Ti,Al)N and Ti(C,N) coated tools are available. This gives the opportunity to compare the performance of different coatings under identical machining conditions and to evaluate causes and phenomena of wear. TiN, (Ti,Al)N and Ti(C,N) coatings on high speed steel (HSS) show different performances in milling and turning of heat treated steel. The thermal and frictional properties of the coating materials affect the structure, the thickness and the flow of the chips, the contact area on the rake face and the tool life. Model tests show the influence of internal cooling and the thermal conductivity of coated HSS inserts. TiN and (Ti,Zr)N PVD coatings on cemented carbides were examined in interrupted turning and in milling of heat treated steel. Experimental results show a significant influence of typical time-temperature cycles of PVD and chemical vapor deposition (CVD) coating processes on the physical data and on the performance of the substrates. PVD coatings increase tool life, especially towards lower cutting speeds into ranges which cannot be applied with CVD coatings. The reason for this is the superior toughness of the PVD coated carbide. The combination of tough, micrograin carbide and PVD coating even enables broaching of case hardened sliding gears at a cutting speed of 66 m min -1 . (orig.)

Nanocomposite tribological coatings with "chameleon" surface adaptation

Science.gov (United States)

Voevodin, A. A.; Fitz, T. A.; Hu, J. J.; Zabinski, J. S.

2002-07-01

Nanocomposite tribological coatings were designed to respond to changing environmental conditions by self-adjustment of their surface properties to maintain good tribological performance in any environment. These smart coatings have been dubbed "chameleon" because, analogous to a chameleon changing its skin color to avoid predators, the coating changes its "skin" chemistry and structure to avoid wear. The concept was originally developed using WC, diamondlike carbon, and WS2 material combination for adaptation to a humid/dry environment cycling. In order to address temperature variation, nanocomposite coatings made of yttria-stabilized zirconia (YSZ) in a gold matrix were developed with encapsulated nanosized reservoirs of MoS2 and diamondlike carbon (DLC). Coatings were produced using a combination of laser ablation and magnetron sputtering. They were characterized by x-ray photoelectron spectroscopy, x-ray diffraction, transmission electron microscopy, x-ray energy dispersive spectroscopy, and micro-Raman spectroscopy. Results were correlated with mechanical and tribological characterization. Coating hardness was evaluated using nanoindentation, while coating adhesion and toughness were estimated using scratch and Vickers indentation tests. Friction and wear endurance measurements of YSZ/Au/MoS2/DLC coatings against steel and Si3N4 balls were performed at room temperature in controlled humidity air, dry nitrogen, and vacuum environments, as well as at 500 degC in air. Depending on the environment, coating friction surface changed its chemistry and structure between (i) graphitic carbon for sliding in humid air [coating friction coefficients (c.o.f. 0.10-0.15)], (ii) hexagonal MoS2 for sliding in dry N2 and vacuum (c.o.f. 0.02-0.05), and (iii) metallic Au for sliding in air at 500 degC (c.o.f. 0.10-0.20). The unique coating skin adaptation realized with YSZ/Au/MoS2/DLC and WC/DLC/WS composites proves a universal applicability of the chameleon design concept

Nanocomposite tribological coatings with 'chameleon' surface adaptation

International Nuclear Information System (INIS)

Voevodin, A.A.; Fitz, T.A.; Hu, J.J.; Zabinski, J.S.

2002-01-01

Nanocomposite tribological coatings were designed to respond to changing environmental conditions by self-adjustment of their surface properties to maintain good tribological performance in any environment. These smart coatings have been dubbed 'chameleon' because, analogous to a chameleon changing its skin color to avoid predators, the coating changes its 'skin' chemistry and structure to avoid wear. The concept was originally developed using WC, diamondlike carbon, and WS 2 material combination for adaptation to a humid/dry environment cycling. In order to address temperature variation, nanocomposite coatings made of yttria-stabilized zirconia (YSZ) in a gold matrix were developed with encapsulated nanosized reservoirs of MoS 2 and diamondlike carbon (DLC). Coatings were produced using a combination of laser ablation and magnetron sputtering. They were characterized by x-ray photoelectron spectroscopy, x-ray diffraction, transmission electron microscopy, x-ray energy dispersive spectroscopy, and micro-Raman spectroscopy. Results were correlated with mechanical and tribological characterization. Coating hardness was evaluated using nanoindentation, while coating adhesion and toughness were estimated using scratch and Vickers indentation tests. Friction and wear endurance measurements of YSZ/Au/MoS 2 /DLC coatings against steel and Si 3 N 4 balls were performed at room temperature in controlled humidity air, dry nitrogen, and vacuum environments, as well as at 500 deg. C in air. Depending on the environment, coating friction surface changed its chemistry and structure between (i) graphitic carbon for sliding in humid air [coating friction coefficients (c.o.f. 0.10-0.15)], (ii) hexagonal MoS 2 for sliding in dry N 2 and vacuum (c.o.f. 0.02-0.05), and (iii) metallic Au for sliding in air at 500 deg. C (c.o.f. 0.10-0.20). The unique coating skin adaptation realized with YSZ/Au/MoS 2 /DLC and WC/DLC/WS composites proves a universal applicability of the chameleon design

Bioceramic coating of hydroxyapatite on titanium substrate with Nd-YAG laser

International Nuclear Information System (INIS)

Cheng, Gary J.; Pirzada, Daniel; Cai, M.; Mohanty, Pravansu; Bandyopadhyay, Amit

2005-01-01

The ability to bond to bone tissue is a unique property of bioactive ceramics. Hydroxyapatite (HAp) is one of the potential bioceramics candidates due to its superior bio-compatibility. Significant effort has been devoted to coat HAp ceramics on metallic substrates. Most of these processes, such as ion-beam sputter coating, thermal spraying, and flame spraying, are high temperature line of sight processes, which suffer from undesirable phase formation and weak metal/HAP bonding strength. This paper presents a unique process to coat HAp powders on titanium substrates at low temperature and enhance the coating/substrate interface by laser surface engineering. Nd-YAG laser transmits HAp powders and the laser power is absorbed by titanium substrate to produce a thin layer of molten region. During coating process, HAp powders are kept at low temperature before they are entrapped in metallic layer. Scanning electron microscope (SEM) was used to investigate the microstructure of coating; the chemical composition of the coating is determined by energy dispersive spectrometry (EDS). Mechanical properties of the interface between coating and Ti substrate were investigated by nanoindentation

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)

Protection of uranium by metallic coatings

International Nuclear Information System (INIS)

Baque, P.; Koch, P.; Dominget, R.; Darras, R.

1968-01-01

A study is made of the possibilities of inhibiting or limiting, by means of protective metallic coatings, the oxidation of uranium by carbon dioxide at high temperature. In general, surface films containing intermetallic compounds or solid solutions of uranium with aluminium, zirconium, copper, niobium, nickel or chromium are formed, according to the techniques employed which are described here. The processes most to be recommended are those of direct diffusion starting from a thin sheet or tube, of vacuum deposition, or of immersion in a molten bath of suitable composition. The conditions for preparing these coatings have been optimized as a function of the protective effect obtained in carbon dioxide at 450 or at 500 C. Only the aluminium and zirconium based coatings are really satisfactory since they can lead to a reduction by a factor of 5 to 10 in the oxidation rate of uranium in the conditions considered; they make it possible in particular to avoid or to reduce to a very large extent the liberation of powdered oxide. Furthermore, the coatings produced generally give the uranium good protection against atmospheric corrosion. (author) [fr

Microstructure of Al-Si Slurry Coatings on Austenitic High-Temperature Creep Resisting Cast Steel

Directory of Open Access Journals (Sweden)

Agnieszka E. Kochmańska

2018-01-01

Full Text Available This paper presents the results of microstructural examinations on slurry aluminide coatings using scanning electron microscopy, X-ray microanalysis, and X-ray diffraction. Aluminide coatings were produced in air atmosphere on austenitic high-temperature creep resisting cast steel. The function of aluminide coatings is the protection of the equipment components against the high-temperature corrosion in a carburising atmosphere under thermal shock conditions. The obtained coatings had a multilayered structure composed of intermetallic compounds. The composition of newly developed slurry was powders of aluminium and silicon; NaCl, KCl, and NaF halide salts; and a water solution of a soluble glass as an inorganic binder. The application of the inorganic binder in the slurry allowed to produce the coatings in one single step without additional annealing at an intermediate temperature as it is when applied organic binder. The coatings were formed on both: the ground surface and on the raw cast surface. The main technological parameters were temperature (732–1068°C and time of annealing (3.3–11.7 h and the Al/Si ratio (4–14 in the slurry. The rotatable design was used to evaluate the effect of the production parameters on the coatings thickness. The correlation between the technological parameters and the coating structure was determined.

Effect of thermophysical property and coating thickness on microstructure and characteristics of a casting

Directory of Open Access Journals (Sweden)

Ai-chao Cheng

2017-01-01

Full Text Available A new improved investment casting technology (IC has been presented and compared with the existing IC technology such as lost foam casting (LFC. The effect of thermophysical property and coating thickness on casting solidification temperature field, microstructure and hardness has been investigated. The results show that the solidification rate decreases inversely with the coating thickness when the coating contains silica sol, zircon powder, mullite powder and defoaming agent. In contrast, the solid cooling rate increases as the coating thickness increases. However, the solidification rate and solid cooling rate of the casting produced by the existing IC and the improved IC are very similar when the coating thickness is 5 mm, so the microstructure and hardness of a container corner fitting produced by the improved IC and the existing IC are similar. The linear regression equation for the grain size (d and cooling rate (v of the castings is d= –0.41v+206.1. The linear regression equation for the content of pearlite (w and solid cooling rate (t is w=1.79t + 6.71. The new improved IC can greatly simplify the process and decrease the cost of production compared with the existing IC. Contrasting with LFC, container corner fittings produced by the new improved IC have fewer defects and better properties. It was also found that the desired microstructure and properties can be obtained by changing the thermophysical property and thickness of the coating.

Uranium dispersion in the coating of weak-acid-resin-deprived HTGR fuel microspheres

International Nuclear Information System (INIS)

Weber, G.W.; Beatty, R.L.; Tennery, V.J.; Lackey, W.J. Jr.

1976-02-01

The current reference HTGR recycle fuel particle is a UO 2 /UC 2 kernel with a Triso coating comprising a low-density pyrocarbon (PyC) buffer, a high-density PyC inner LTI coating, SiC, and a high-density PyC outer LTI. The kernel is fabricated from a weak-acid ion exchange resin (WAR). Microradiographic examination of coated WAR particles has demonstrated that considerable U can be transferred from the kernel to the buffer coating during fabrication. Investigation of causes of fuel dispersion has indicated several different factors that contribute to fuel redistribution if not properly controlled. The presence of a nonequilibrium UC/sub 1-x/O/sub x/ (0 less than or equal to x less than or equal to 0.3) phase had no significant effect on initiating fuel dispersion. Gross exposure of the completed fuel kernel to ambient atmosphere or to water vapor at room temperature produced very minimal levels of dispersion. Exposure of the fuel to perchloroethylene during buffer and inner LTI deposition produced massive redistribution. Fuel redistribution observed in Triso-coated particles results from permeation of the inner LTI by HCl during SiC deposition. As the decomposition of CH 3 Cl 3 Si is used to deposit SiC, chlorine is readily available during this process. The permeability of the inner LTI coating has a marked effect on the extent of this mode of fuel dispersion. LTI permeability was determined by chlorine leaching studies to be a strong function of density, coating gas dilution, and coating temperature but relatively unaffected by application of a seal coat, variations in coating thickness, and annealing at 1800 0 C. Mechanical attrition of the kernels during processing was identified as a potential source of U-bearing fines that may be incorporated into the coating in some circumstances

Development & characterization of alumina coating by atmospheric plasma spraying

Science.gov (United States)

Sebastian, Jobin; Scaria, Abyson; Kurian, Don George

2018-03-01

Ceramic coatings are applied on metals to prevent them from oxidation and corrosion at room as well as elevated temperatures. The service environment, mechanisms of protection, chemical and mechanical compatibility, application method, control of coating quality and ability of the coating to be repaired are the factors that need to be considered while selecting the required coating. The coatings based on oxide materials provides high degree of thermal insulation and protection against oxidation at high temperatures for the underlying substrate materials. These coatings are usually applied by the flame or plasma spraying methods. The surface cleanliness needs to be ensured before spraying. Abrasive blasting can be used to provide the required surface roughness for good adhesion between the substrate and the coating. A pre bond coat like Nickel Chromium can be applied on to the substrate material before spraying the oxide coating to avoid chances of poor adhesion between the oxide coating and the metallic substrate. Plasma spraying produces oxide coatings of greater density, higher hardness, and smooth surface finish than that of the flame spraying process Inert gas is often used for generation of plasma gas so as to avoid the oxidation of the substrate material. The work focuses to develop, characterize and optimize the parameters used in Al2O3 coating on transition stainless steel substrate material for minimizing the wear rate and maximizing the leak tightness using plasma spray process. The experiment is designed using Taguchi’s L9 orthogonal array. The parameters that are to be optimized are plasma voltage, spraying distance and the cooling jet pressure. The characterization techniques includes micro-hardness and porosity tests followed by Grey relational analysis of the results.

Internal oxidation of laminated ternary Ru–Ta–Zr coatings

Energy Technology Data Exchange (ETDEWEB)

Chen, Yung-I, E-mail: yichen@mail.ntou.edu.tw; Lu, Tso-Shen

2015-10-30

Highlights: • Internal oxidation was observed in annealed and laminated Ru–Ta–Zr coatings. • The oxidized Ru–Ta–Zr coatings comprised three alternately stacked sublayers. • Correlated variations of O{sup 2-} and Zr{sup 4+} binding energies were verified in XPS spectra. - Abstract: Researchers have observed the internal oxidation phenomenon in binary alloy coatings when developing refractory alloy coatings for protective purposes by conducting annealing at high temperatures and in oxygen-containing atmospheres. The coatings were assembled using cyclical gradient concentration deposition during cosputtering by employing a substrate holder rotating at a slow speed. The internally oxidized zone demonstrated a laminated structure, comprising alternating oxygen-rich and oxygen-deficient layers stacked in a general orientation. In the current study, Ru–Ta–Zr coatings were prepared with various stacking sequences during cosputtering. The Ru–Ta–Zr coatings were annealed at 600 °C in an atmosphere continuously purged with 1% O{sub 2}–99% Ar mixed gas for 30 min. A transmission electron microscope was used to examine the periods of the laminated layers and crystallinity of the annealed coatings. Depth profiles produced using an Auger electron spectroscope and X-ray photoelectron spectroscope were used to certify the periodic variation of the related constituents and chemical states of the elements, respectively. The results indicate that the internally oxidized ternary coatings are stacked of Ru-, Ta{sub 2}O{sub 5}-, and ZrO{sub 2}-dominant sublayers and that the stacking sequences of the sublayers affect the crystalline structure of the coatings. Zr is oxidized preferentially in the Ru–Ta–Zr coatings, increasing the surface hardness of the oxidized coatings.

Effect of surface coating with magnesium stearate via mechanical dry powder coating approach on the aerosol performance of micronized drug powders from dry powder inhalers.

Science.gov (United States)

Zhou, Qi Tony; Qu, Li; Gengenbach, Thomas; Larson, Ian; Stewart, Peter J; Morton, David A V

2013-03-01

The objective of this study was to investigate the effect of particle surface coating with magnesium stearate on the aerosolization of dry powder inhaler formulations. Micronized salbutamol sulphate as a model drug was dry coated with magnesium stearate using a mechanofusion technique. The coating quality was characterized by X-ray photoelectron spectroscopy. Powder bulk and flow properties were assessed by bulk densities and shear cell measurements. The aerosol performance was studied by laser diffraction and supported by a twin-stage impinger. High degrees of coating coverage were achieved after mechanofusion, as measured by X-ray photoelectron spectroscopy. Concomitant significant increases occurred in powder bulk densities and in aerosol performance after coating. The apparent optimum performance corresponded with using 2% w/w magnesium stearate. In contrast, traditional blending resulted in no significant changes in either bulk or aerosolization behaviour compared to the untreated sample. It is believed that conventional low-shear blending provides insufficient energy levels to expose host micronized particle surfaces from agglomerates and to distribute guest coating material effectively for coating. A simple ultra-high-shear mechanical dry powder coating step was shown as highly effective in producing ultra-thin coatings on micronized powders and to substantially improve the powder aerosolization efficiency.

Aluminium-rich coatings as tritium permeation barriers on MANET (1.4914) stainless steel

International Nuclear Information System (INIS)

Terlain, A.; De Vito, E.

1994-01-01

Al-rich coatings on 1.4914 martensitic steel, produced by different techniques, have been investigated with optical and scanning electron microscopy, X-ray fluorescence and X-ray photoelectron spectroscopy. Tests for their Pb-17Li compatibility and thermo cycling behaviours have been performed on some coated specimens. Up to now, none of the investigated coatings can be eliminated on the basis of the tests and analyses performed. Further work is required to adapt 1.4914 steel coating techniques to fusion reactor requirements. (author) 9 refs.; 5 figs.; 1 tab

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.

Replacement for a Flex Hose Coating at the Space Shuttle Launch Pad

Science.gov (United States)

Whitten, Mary; Vinje, Rubiela; Curran, Jerome; Meneghelli, Barry; Calle, Luz Marina

2009-01-01

Aerocoat AR-7 is a coating that has been used to protect stainless steel flex hoses at NASA's Kennedy Space Center launch complex and hydraulic lines of the mobile launch platform (MLP). This coating has great corrosion control performance and low temperature application. AR-7 was developed by NASA and produced exclusively for NASA but its production has been discontinued due to its high content of volatile organic compounds (VOC) and significant environmental impact. The purpose of this project was to select and evaluate candidate coatings to find a replacement coating that is more environmentally friendly, with similar properties to AR-7. No coatings were identified that perform the same as AR-7 in all areas. Candidate coatings failed in comparison to AR-7 in salt fog, beachside atmospheric exposure, pencil hardness, Mandrel bend, chemical compatibility, adhesion, and ease of application tests. However, two coatings were selected for further evaluation.

Functional patterned coatings by thin polymer film dewetting.

Science.gov (United States)

Telford, Andrew M; Thickett, Stuart C; Neto, Chiara

2017-12-01

An approach for the fabrication of functional polymer surface coatings is introduced, where micro-scale structure and surface functionality are obtained by means of self-assembly mechanisms. We illustrate two main applications of micro-patterned polymer surfaces obtained through dewetting of bilayers of thin polymer films. By tuning the physical and chemical properties of the polymer bilayers, micro-patterned surface coatings could be produced that have applications both for the selective attachment and patterning of proteins and cells, with potential applications as biomaterials, and for the collection of water from the atmosphere. In all cases, the aim is to achieve functional coatings using approaches that are simple to realize, use low cost materials and are potentially scalable. Copyright © 2017 Elsevier Inc. All rights reserved.

Fabrication of Polymeric Coatings with Controlled Microtopographies Using an Electrospraying Technique.

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Qiongyu Guo

Full Text Available Surface topography of medical implants provides an important biophysical cue on guiding cellular functions at the cell-implant interface. However, few techniques are available to produce polymeric coatings with controlled microtopographies onto surgical implants, especially onto implant devices of small dimension and with complex structures such as drug-eluting stents. Therefore, the main objective of this study was to develop a new strategy to fabricate polymeric coatings using an electrospraying technique based on the uniqueness of this technique in that it can be used to produce a mist of charged droplets with a precise control of their shape and dimension. We hypothesized that this technique would allow facile manipulation of coating morphology by controlling the shape and dimension of electrosprayed droplets. More specifically, we employed the electrospraying technique to coat a layer of biodegradable polyurethane with tailored microtopographies onto commercial coronary stents. The topography of such stent coatings was modulated by controlling the ratio of round to stretched droplets or the ratio of round to crumped droplets under high electric field before deposition. The shape of electrosprayed droplets was governed by the stability of these charged droplets right after ejection or during their flight in the air. Using the electrospraying technique, we achieved conformal polymeric coatings with tailored microtopographies onto conductive surgical implants. The approach offers potential for controlling the surface topography of surgical implant devices to modulate their integration with surrounding tissues.

Tribological performance of an H-DLC coating prepared by PECVD

Energy Technology Data Exchange (ETDEWEB)

Solis, J., E-mail: jsolis@ittla.edu.mx [IFS, University of Leeds, School of Mechanical Engineering, Leeds, LS2 9JT (United Kingdom); SEP/SES/TecNM/IT de Tlalnepantla, DEPI-Mechanical Engineering, 54070, Edo. Méx. (Mexico); Zhao, H.; Wang, C. [IFS, University of Leeds, School of Mechanical Engineering, Leeds, LS2 9JT (United Kingdom); Verduzco, J.A. [Instituto de Investigación en Metalurgia y Materiales, UMSNH, P.O. Box 888, 58000, Morelia, Mich. (Mexico); Bueno, A.S. [IFS, University of Leeds, School of Mechanical Engineering, Leeds, LS2 9JT (United Kingdom); Mechanical Engineering Department, Universidade Federal de São João Del Rei, 170 Praça Frei Orlando, 36307-352 São João Del Rei (Brazil); Neville, A. [IFS, University of Leeds, School of Mechanical Engineering, Leeds, LS2 9JT (United Kingdom)

2016-10-15

Highlights: • Duplex hydrogenated Diamond-like Carbon was produced and characterised. • Friction and wear under dry condition of H-DLC/steel tribopair was assessed. • Adhesive strength of the coating was 80N after the scratch tests under dry condition. • Maximum and minimum values of average coefficient of friction were 0.21 and 0.13. • A protective transferred layer on the counterpart produced a carbon-carbon contact. - Abstract: Carbon-based coatings are of wide interest due to their application in machine elements subjected to continuous contact where fluid lubricant films are not permitted. This paper describes the tribological performance under dry conditions of duplex layered H-DLC coating sequentially deposited by microwave excited plasma enhanced chemical vapour deposition on AISI 52100 steel. The architecture of the coating comprised Cr, WC, and DLC (a-C:H) with a total thickness of 2.8 μm and compressive residual stress very close to 1 GPa. Surface hardness was approximately 22 GPa and its reduced elastic modulus around 180 GPa. Scratch tests indicated a well adhered coating achieving a critical load of 80 N. The effect of normal load on the friction and wear behaviours were investigated with steel pins sliding against the actual coating under dry conditions at room temperature (20 ± 2 °C) and 35–50% RH. The results show that coefficient of friction of the coating decreased from 0.21 to 0.13 values with the increase in the applied loads (10–50 N). Specific wear rates of the surface coating also decrease with the increase in the same range of applied loads. Maximum and minimum values were 14 × 10{sup −8} and 5.5 × 10{sup −8} mm{sup −3}/N m, respectively. Through Raman spectroscopy and electron microscopy it was confirmed the carbon-carbon contact, due to the tribolayer formation on the wear scars of the coating and pin. In order to further corroborate the experimental observations regarding the graphitisation behaviour, the

Tribological behavior at elevated temperature of multilayer TiCN/TiC/TiN hard coatings produced by chemical vapor deposition

International Nuclear Information System (INIS)

Bao Mingdong; Xu Xuebo; Zhang Haijun; Liu Xiaoping; Tian Linhai; Zeng Zhaoxin; Song Yubin

2011-01-01

Multilayer hard coatings of TiCN/TiC/TiN on high speed steel substrates were deposited using a chemical vapor deposition system. Evaluations of microstructure, wear morphology of coatings were characterized by scanning electron microscopy, and optical microscopy. Friction coefficient and wear rates of coatings were investigated using ball-on-disk tester sliding against a WC ball at a constant load of 20 N. Tribological behavior of the coatings at room and elevated temperature were discussed. Different changing tendency of friction coefficient were observed from ball-on-disc experiments. Results showed that the friction coefficient of coatings increased gradually to a highest value, then to a relatively constant value at room temperature dry sliding wear. The friction coefficient exhibited a reverse variation tendency at temperature of 550 °C. It got a higher value at the first sliding friction cycles. Then the value of friction coefficient decreased, suffered irregular oscillations and kept a relatively lower value with increasing sliding time. Reasons of the variation of friction coefficient with sliding time and wear mechanism were analyzed and discussed at room and elevated temperatures, respectively.

Active coatings technologies for tailorable military coating systems

Science.gov (United States)

Zunino, J. L., III

2007-04-01

The main objective of the U.S. Army's Active Coatings Technologies Program is to develop technologies that can be used in combination to tailor coatings for utilization on Army Materiel. The Active Coatings Technologies Program, ACT, is divided into several thrusts, including the Smart Coatings Materiel Program, Munitions Coatings Technologies, Active Sensor packages, Systems Health Monitoring, Novel Technology Development, as well as other advanced technologies. The goal of the ACT Program is to conduct research leading to the development of multiple coatings systems for use on various military platforms, incorporating unique properties such as self repair, selective removal, corrosion resistance, sensing, ability to modify coatings' physical properties, colorizing, and alerting logistics staff when tanks or weaponry require more extensive repair. A partnership between the U.S. Army Corrosion Office at Picatinny Arsenal, NJ along with researchers at the New Jersey Institute of Technology, NJ, Clemson University, SC, University of New Hampshire, NH, and University of Massachusetts (Lowell), MA, are developing the next generation of Smart Coatings Materiel via novel technologies such as nanotechnology, Micro-electromechanical Systems (MEMS), meta-materials, flexible electronics, electrochromics, electroluminescence, etc. This paper will provide the reader with an overview of the Active Coatings Technologies Program, including an update of the on-going Smart Coatings Materiel Program, its progress thus far, description of the prototype Smart Coatings Systems and research tasks as well as future nanotechnology concepts, and applications for the Department of Defense.

New coating material for producing virgin coconut oil (VCO microcapsules