Effect of zinc phosphate chemical conversion coating on corrosion behaviour of mild steel in alkaline medium: protection of rebars in reinforced concrete

Directory of Open Access Journals (Sweden)

Florica Simescu and Hassane Idrissi

2008-01-01

Full Text Available We outline the ability of zinc phosphate coatings, obtained by chemical conversion, to protect mild steel rebars against localized corrosion, generated by chloride ions in alkaline media. The corrosion resistance of coated steel, in comparison with uncoated rebars and coated and uncoated steel rebars embedded in mortar, were evaluated by open-circuit potential, potentiodynamic polarization, cronoamperometry and electrochemical impedance spectroscopy. The coated surfaces were characterized by x-ray diffraction and scanning electron microscopy. First, coated mild steel rebars were studied in an alkaline solution with and without chloride simulating a concrete pore solution. The results showed that the slow dissolution of the coating generates hydroxyapatite Ca10(PO46(OH2. After a long immersion, the coating became dense and provided an effective corrosion resistance compared with the mild steel rebar. Secondly, the coated and uncoated steel rebars embedded in mortar and immersed in chloride solution showed no corrosion or deterioration of the coated steel. Corrosion rate is considerably lowered by this phosphate coating.

Microstructure and electrochemical behavior of cerium conversion coating modified with silane agent on magnesium substrates

Science.gov (United States)

Lei, Li; Shi, Jing; Wang, Xin; Liu, Dan; Xu, Haigang

2016-07-01

The cerium conversion coating with and without different concentrations of silane agent bis-(γ-triethoxysilylpropyl)-tetrasulfide (BTESPT) modification is obtained on magnesium alloys. Detailed properties of the coatings and the role of BTESPT as an additive are studied and followed with careful discussion. The coating morphology, wettability, chemical composition and corrosion resistance are characterized by scanning electronic microscope (SEM), water contact-angle, X-ray photoelectron spectroscopy (XPS), potentiodynamic measurements and electrochemical impedance spectroscopy (EIS). The electrochemical behavior of the coatings is investigated using EIS. The results indicate that the coating morphology and composition can be controlled by changing silane concentration. The combination of cerium ions and silane molecules could promote the formation of more homogenous and higher hydrophobic coating. The coating turns to be more compact and the adhesive strength between the coating and the magnesium substrate are strongly improved with the formation of Sisbnd Osbnd Si and Sisbnd Osbnd M chemical bonds. The optimum corrosion resistance of the coating in the corrosive media is obtained by 25 ml L-1 BTESPT modification. This whole study implies that the cerium conversion coating modified with certain silane agent deserves cautiousness before its application for corrosion resistance.

Microstructure and electrochemical behavior of cerium conversion coating modified with silane agent on magnesium substrates

Energy Technology Data Exchange (ETDEWEB)

Lei, Li; Shi, Jing, E-mail: shijing@ouc.edu.cn; Wang, Xin, E-mail: wangxin.hd@163.com; Liu, Dan; Xu, Haigang

2016-07-15

Graphical abstract: The unmodified coating shows averaged static water contact angles of a little more than 50º, which is clearly hydrophilic for water solutions. With the silane concentration increases, the water contact angles show an increase tendency. Especially, when the silane addition is increased to 25 ml L-1, the coating surface presents a hydrophobic feature, with static water contact angle of more than 110º. - Highlights: • BTESPT modification can effectively improve the uniformity, hydrophobic performance, chemical stability and corrosion inhibition capability of traditional cerium conversion coating. • Si-O-Si linkage builds a robust structure to increase of the coating density. Si−O−Mg bonds strengthen the adhesion between the coating/substrate. • The system modified with 25 ml L{sup −1} BTESPT displays the optimum corrosion protection performance. - Abstract: The cerium conversion coating with and without different concentrations of silane agent bis-(γ-triethoxysilylpropyl)-tetrasulfide (BTESPT) modification is obtained on magnesium alloys. Detailed properties of the coatings and the role of BTESPT as an additive are studied and followed with careful discussion. The coating morphology, wettability, chemical composition and corrosion resistance are characterized by scanning electronic microscope (SEM), water contact-angle, X-ray photoelectron spectroscopy (XPS), potentiodynamic measurements and electrochemical impedance spectroscopy (EIS). The electrochemical behavior of the coatings is investigated using EIS. The results indicate that the coating morphology and composition can be controlled by changing silane concentration. The combination of cerium ions and silane molecules could promote the formation of more homogenous and higher hydrophobic coating. The coating turns to be more compact and the adhesive strength between the coating and the magnesium substrate are strongly improved with the formation of Si−O−Si and Si�

Microstructure and electrochemical behavior of cerium conversion coating modified with silane agent on magnesium substrates

International Nuclear Information System (INIS)

Lei, Li; Shi, Jing; Wang, Xin; Liu, Dan; Xu, Haigang

2016-01-01

Graphical abstract: The unmodified coating shows averaged static water contact angles of a little more than 50º, which is clearly hydrophilic for water solutions. With the silane concentration increases, the water contact angles show an increase tendency. Especially, when the silane addition is increased to 25 ml L-1, the coating surface presents a hydrophobic feature, with static water contact angle of more than 110º. - Highlights: • BTESPT modification can effectively improve the uniformity, hydrophobic performance, chemical stability and corrosion inhibition capability of traditional cerium conversion coating. • Si-O-Si linkage builds a robust structure to increase of the coating density. Si−O−Mg bonds strengthen the adhesion between the coating/substrate. • The system modified with 25 ml L"−"1 BTESPT displays the optimum corrosion protection performance. - Abstract: The cerium conversion coating with and without different concentrations of silane agent bis-(γ-triethoxysilylpropyl)-tetrasulfide (BTESPT) modification is obtained on magnesium alloys. Detailed properties of the coatings and the role of BTESPT as an additive are studied and followed with careful discussion. The coating morphology, wettability, chemical composition and corrosion resistance are characterized by scanning electronic microscope (SEM), water contact-angle, X-ray photoelectron spectroscopy (XPS), potentiodynamic measurements and electrochemical impedance spectroscopy (EIS). The electrochemical behavior of the coatings is investigated using EIS. The results indicate that the coating morphology and composition can be controlled by changing silane concentration. The combination of cerium ions and silane molecules could promote the formation of more homogenous and higher hydrophobic coating. The coating turns to be more compact and the adhesive strength between the coating and the magnesium substrate are strongly improved with the formation of Si−O−Si and Si−O−M chemical

Examination of Nonchromate Conversion Coatings for Aluminum Armor From Three Final Candidates Using Accelerated Corrosion and Adhesion Test Methods

National Research Council Canada - National Science Library

Placzankis, Brian

2001-01-01

This study examines the effectiveness of three final candidate nonchromate conversion coatings on aluminum alloys 5083, 7039, and 6061 coated with standard solvent-based Chemical Agent Resistant Coating (CARC) system...

Effect of HCl pre-treatment on corrosion resistance of cerium-based conversion coatings on magnesium and magnesium alloys

International Nuclear Information System (INIS)

Brunelli, Katya; Dabala, Manuele; Calliari, Irene; Magrini, Maurizio

2005-01-01

The corrosion protection afforded by a cerium conversion coating, formed by immersion in a solution containing rare earth salt and hydrogen peroxide, on pure magnesium and two magnesium alloys, AZ91 and AM50, has been studied. The effect of HCl pre-treatments on the morphology and on the corrosion resistance of the cerium conversion layer was investigated. A thicker and more homogeneous distribution of the conversion coating was obtained when the sample surface was pre-treated with acid. Higher amounts of cerium on the surface of the pre-treated samples were detected. The cerium conversion coating increased the corrosion resistance of the alloys because it ennobled the corrosion potential and decreased both the anodic and cathodic current. The acid pre-treatment further increased the corrosion resistance of the coated alloys. After five days of immersion in chloride environment the untreated samples showed localized corrosion while the chemical conversion coated samples appeared unaffected

Chemical and structural analyses of subsurface crevices formed during spontaneous deposition of cerium-based conversion coatings

Energy Technology Data Exchange (ETDEWEB)

Heller, Daimon K, E-mail: dkheller@mmm.com; Fahrenholtz, William G., E-mail: billf@mst.edu; O' Keefe, Matthew J., E-mail: mjokeefe@mst.edu

2011-11-15

Subsurface crevices formed during the deposition of cerium-based conversion coatings were analyzed in cross-section to assess the effect of deposition and post-treatment on the structure and chemistry of phases present. An Al-O containing phase, believed to be amorphous Al(OH){sub 3}, was formed in crevices during coating deposition. Analysis by energy dispersive X-ray spectroscopy revealed the presence of up to 1.6 at.% chlorine within the Al-O phase, which was likely a product of soluble chlorides that were present in the coating solution. Cerium was not detected within crevices. After post-treatment in an 85 deg. C aqueous phosphate solution, the chloride concentration was reduced to {<=} 0.30 at.% and electron diffraction of the Al-O phase produced ring patterns, indicating it had crystallized. Some diffraction patterns could be indexed to gibbsite (Al(OH){sub 3}), but others are believed to be a combination of hydrated aluminum hydroxides and/or oxides. Aluminum phosphate was not identified. Separately from its effect on cerium-based conversion coatings, phosphate post-treatment improved the corrosion resistance of Al 2024-T3 substrates by acting to crystallize Al(OH){sub 3} present on interior surfaces of crevices and by reducing the chloride concentration in this phase. - Highlights: {yields} Analysis of subsurface crevices formed during deposition of Ce-based conversion coatings. {yields} Phosphate post-treatment improved corrosion protection in salt spray testing. {yields} Post-treatment affected the composition and structure of regions within crevices. {yields} Crystallized Al(OH){sub 3} within crevices acted as a more effective barrier to chloride ions.

Steam generated conversion coating on aluminium alloys

DEFF Research Database (Denmark)

Din, Rameez Ud; Jellesen, Morten Stendahl; Ambat, Rajan

Aluminium and its alloys are widely used in aerospace industry owing to their high strength to weight ratio. The surface of aluminium under normal conditions has a thin oxide film (2.5-10 nm) responsible for its inherent corrosion resistance. This oxide film can further be converted or transformed...... into functional conversion coatings in order to enhance corrosion resistance and adhesion to paint systems. Chromium based conversion coatings have been extensively used on aluminium alloys to improve adhesion of subsequent paint layers and corrosion resistance. However, the use of hexavalent chromium is strictly...... regulated due to its toxic nature and suspected carcinogenicity. So, it is highly imperative to develop other alternatives for chrome conversion coatings. Treatment of aluminium with natural water at elevated temperatures results in the formation of different forms of aluminium oxide (γ-AlO(OH) , Al(OH)3...

Anti-corrosive Conversion Coating on Aluminium Alloys Using High Temperature Steam

DEFF Research Database (Denmark)

Din, Rameez Ud; Jellesen, Morten Stendahl; Ambat, Rajan

or convert to a functional conversion coating. In the last several decades chromate conversion coating (CrCCs) have been the most common conversion coatings used for aluminium alloys. Due to the toxicity of the hexavalent chrome, however, environmental friendly alternatives to CrCCs have been investigated...

In Vitro Corrosion and Cytocompatibility of ZK60 Magnesium Alloy Coated with Hydroxyapatite by a Simple Chemical Conversion Process for Orthopedic Applications

Science.gov (United States)

Wang, Bing; Huang, Ping; Ou, Caiwen; Li, Kaikai; Yan, Biao; Lu, Wei

2013-01-01

Magnesium and its alloys—a new class of degradable metallic biomaterials—are being increasingly investigated as a promising alternative for medical implant and device applications due to their advantageous mechanical and biological properties. However, the high corrosion rate in physiological environments prevents the clinical application of Mg-based materials. Therefore, the objective of this study was to develop a hydroxyapatite (HA) coating on ZK60 magnesium alloy substrates to mediate the rapid degradation of Mg while improving its cytocompatibility for orthopedic applications. A simple chemical conversion process was applied to prepare HA coating on ZK60 magnesium alloy. Surface morphology, elemental compositions, and crystal structures were characterized using scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction, respectively. The corrosion properties of samples were investigated by immersion test and electrochemical test. Murine fibroblast L-929 cells were harvested and cultured with coated and non-coated ZK60 samples to determine cytocompatibility. The degradation results suggested that the HA coatings decreased the degradation of ZK60 alloy. No significant deterioration in compression strength was observed for all the uncoated and coated samples after 2 and 4 weeks’ immersion in simulated body fluid (SBF). Cytotoxicity test indicated that the coatings, especially HA coating, improved cytocompatibility of ZK60 alloy for L929 cells. PMID:24300096

Stannate conversion coatings on Mg-8Li alloy

International Nuclear Information System (INIS)

Yang Lihui; Zhang Milin; Li Junqing; Yu Xiang; Niu Zhongyi

2009-01-01

The stannate conversion coatings (SnCC) on Mg-8Li alloy were investigated by simple immersion method. The surface morphology and composition were studied by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction spectroscopy (XRD) techniques. The corrosion resistance was assessed by means of potentiodynamic polarization measurements and electrochemical impedance spectra (EIS). The effects of time of a stannate bath on the quality of stannate conversion coatings were investigated by SEM and EIS. It was found that the coating particles were mainly composed of hemispherical particles MgSnO 3 .3H 2 O. A comparison of results revealed the coating treated for 60 min exhibited the most uniform, dense and corrosion-resistant

Effects of pH and temperature on the deposition properties of stannate chemical conversion coatings formed by the potentiostatic technique on AZ91 D magnesium alloy

International Nuclear Information System (INIS)

Elsentriecy, Hassan H.; Azumi, Kazuhisa; Konno, Hidetaka

2008-01-01

The effects of pH and temperature of a stannate bath on the quality of stannate chemical conversion coatings formed on AZ91 D magnesium alloy by using the potentiostatic polarization technique at E = -1.1 V were investigated in order to improve uniformity and corrosion protection performance of the coating films. It was found that the uniformity and corrosion resistance of coating films deposited by potentiostatic polarization were closely associated with pH and temperature of the coating bath. The pH and temperature to obtain the best coating film were investigated as a function of corrosion protection performance evaluated by curves of potentiodynamic anodic polarization conducted in borate buffer solution. Scanning electron microscope observation and electrochemical corrosion tests of the stannate-coated samples confirmed significant improvement in uniformity and corrosion resistivity of coating films deposited by the potentiostatic technique by modifying the pH and temperature of the coating bath. It was also found that uniformity and corrosion resistivity of the coating films deposited by the potentiostatic technique were considerably improved compared to those of coatings deposited by the simple immersion method at the best conditions of pH and temperature of the coating bath

Corrosion behaviour of chemical conversion treatments on as-cast Mg-Al alloys: Electrochemical and non-electrochemical methods

International Nuclear Information System (INIS)

Rocca, E.; Juers, C.; Steinmetz, J.

2010-01-01

Magnesium alloys are often used in as-cast conditions. So, the aim of this work is to characterize the corrosion protection of as-cast AZ91D alloys coated with simple chemical conversion (phosphate-permanganate, and cerium-based coatings). With the two coatings, the electrochemical measurements show that the corrosion protection is due to both the inhibition of cathodic and anodic reactions, because of the presence of stable CeO 2 or manganese oxides in basic pH. Nevertheless, the non-electrochemical tests of corrosion are required to bring to light the healing effect of phosphate-permanganate coating compared to Ce-coating and to describe the corrosion behaviour completely. Finally phosphoric and soda pickling associated to phosphate-permanganate conversion treatment or cerium coating are ecologically efficient alternatives to fluoride-based pickling and the chromating treatment.

Unconventional fluoride conversion coating preparation and characterization

Czech Academy of Sciences Publication Activity Database

Drábiková, J.; Fintová, Stanislava; Tkacz, J.; Doležal, P.; Wasserbauer, J.

2017-01-01

Roč. 64, č. 6 (2017), s. 613-619 ISSN 0003-5599 Institutional support: RVO:68081723 Keywords : fluoride conversion coating * magnesium * corrosion Subject RIV: JK - Corrosion ; Surface Treatment of Materials OBOR OECD: Coating and films Impact factor: 0.364, year: 2016 http://www.emeraldinsight.com/doi/abs/10.1108/ACMM-02-2017-1757

Adhesion and corrosion studies of a lithium based conversion coating film on the 2024 aluminum alloy

International Nuclear Information System (INIS)

Castro, M.R.S.; Nogueira, J.C.; Thim, G.P.; Oliveira, M.A.S.

2004-01-01

AA2024-T3-aluminum alloy surfaces were coated using non-chromate and chromate conversion coatings. All coatings were painted with the 10P4-2-primer epoxy resin. Independent on the film formation process, films passed on the substrate/conversion coating wet tape adhesion test. However, only the chromate conversion coating passed on the conversion coating/primer epoxy resin adhesion test. Electrochemical corrosion measurements showed that non-chromate conversion coated surfaces present lower corrosion current density, bigger polarization resistance and less negative corrosion potential than chromate conversion coated surfaces

The formation of neodymium conversion coating and the influence of post-treatment

Energy Technology Data Exchange (ETDEWEB)

Cui Xiufang [School of Materials Science and Chemical Engineering, Harbin Engineering University, 145 Nantong St., Harbin 150001 (China); Jin Guo, E-mail: jg97721@yahoo.com.cn [Center for Biomedical Materials and Engineering, School of Materials Science and Chemical Engineering, Harbin Engineering University, 145 Nantong St., Harbin 150001 (China); Yang Yuyun; Liu Erbao; Lin Lili; Zhong Jinggao [Center for Biomedical Materials and Engineering, School of Materials Science and Chemical Engineering, Harbin Engineering University, 145 Nantong St., Harbin 150001 (China)

2012-01-15

In this paper, neodymium-based conversion coating is used as a substitute for toxic chromate conversion coating on AZ91D magnesium alloys. Its formation and growth were observed via SEM, EDS, XPS, electrochemical tests and weighting experiment. The influence of post-treatment on neodymium conversion coating was measured by FTIR and electrochemical experiments in terms of morphology, component, surface functional group and corrosion resistance. The dissolution of matrix and the deposition of neodymium/magnesium oxides compete with each other in initial time. Then the deposition of neodymium oxides dominates the process. Compact coating is obtained after 20 min immersion and it is mainly made of neodymium oxides and a small amount of magnesium oxides/hydroxides. The coating post-treated is rich in OH{sup -} and PO{sub 4}{sup 3+}. The post-treatment can improve the corrosion resistance of the neodymium conversion coating effectually examined by EIS.

The formation of neodymium conversion coating and the influence of post-treatment

International Nuclear Information System (INIS)

Cui Xiufang; Jin Guo; Yang Yuyun; Liu Erbao; Lin Lili; Zhong Jinggao

2012-01-01

In this paper, neodymium-based conversion coating is used as a substitute for toxic chromate conversion coating on AZ91D magnesium alloys. Its formation and growth were observed via SEM, EDS, XPS, electrochemical tests and weighting experiment. The influence of post-treatment on neodymium conversion coating was measured by FTIR and electrochemical experiments in terms of morphology, component, surface functional group and corrosion resistance. The dissolution of matrix and the deposition of neodymium/magnesium oxides compete with each other in initial time. Then the deposition of neodymium oxides dominates the process. Compact coating is obtained after 20 min immersion and it is mainly made of neodymium oxides and a small amount of magnesium oxides/hydroxides. The coating post-treated is rich in OH - and PO 4 3+ . The post-treatment can improve the corrosion resistance of the neodymium conversion coating effectually examined by EIS.

Corrosion behaviour of chemical conversion treatments on as-cast Mg-Al alloys: Electrochemical and non-electrochemical methods

Energy Technology Data Exchange (ETDEWEB)

Rocca, E. [Institut Jean Lamour UMR CNRS 7198, Nancy Universite - Corrosion Group, B.P. 70239, 54506 Vandoeuvre-Les-Nancy (France)], E-mail: emmanuel.rocca@lcsm.uhp-nancy.fr; Juers, C.; Steinmetz, J. [Institut Jean Lamour UMR CNRS 7198, Nancy Universite - Corrosion Group, B.P. 70239, 54506 Vandoeuvre-Les-Nancy (France)

2010-06-15

Magnesium alloys are often used in as-cast conditions. So, the aim of this work is to characterize the corrosion protection of as-cast AZ91D alloys coated with simple chemical conversion (phosphate-permanganate, and cerium-based coatings). With the two coatings, the electrochemical measurements show that the corrosion protection is due to both the inhibition of cathodic and anodic reactions, because of the presence of stable CeO{sub 2} or manganese oxides in basic pH. Nevertheless, the non-electrochemical tests of corrosion are required to bring to light the healing effect of phosphate-permanganate coating compared to Ce-coating and to describe the corrosion behaviour completely. Finally phosphoric and soda pickling associated to phosphate-permanganate conversion treatment or cerium coating are ecologically efficient alternatives to fluoride-based pickling and the chromating treatment.

Study of electrochemical phosphate conversion coating of metallic surfaces

International Nuclear Information System (INIS)

Gougelin, Patrick

1985-01-01

After an overview on phosphate conversion coating processes, on models of iron electrochemical dissolution, on the passivation phenomenon, and on the phosphate conversion coating treatment, this research thesis reports a detailed study of this last process. The author presents the experimental method, reports the study of this process and of passivation under constant polarization. He reports the use of various techniques and conditions: chrono-amperometry, chrono-potentiometry, cyclic volt-amperometry

SiC Conversion Coating Prepared from Silica-Graphite Reaction

Directory of Open Access Journals (Sweden)

Back-Sub Sung

2017-01-01

Full Text Available The β-SiC conversion coatings were successfully synthesized by the SiO(v-graphite(s reaction between silica powder and graphite specimen. This paper is to describe the effects on the characteristics of the SiC conversion coatings, fabricated according to two different reaction conditions. FE-SEM, FE-TEM microstructural morphologies, XRD patterns, pore size distribution, and oxidation behavior of the SiC-coated graphite were investigated. In the XRD pattern and SAD pattern, the coating layers showed cubic SiC peak as well as hexagonal SiC peak. The SiC coatings showed somewhat different characteristics with the reaction conditions according to the position arrangement of the graphite samples. The SiC coating on graphite, prepared in reaction zone (2, shows higher intensity of beta-SiC main peak (111 in XRD pattern as well as rather lower porosity and smaller main pore size peak under 1 μm.

Titanium composite conversion coating formation on CRS In the presence of Mo and Ni ions: Electrochemical and microstructure characterizations

Energy Technology Data Exchange (ETDEWEB)

Eivaz Mohammadloo, H.; Sarabi, A.A., E-mail: Sarabi@aut.ac.ir

2016-11-30

Highlights: • Eco-friendly protective thin films for covering the CRS substrates were presented. • Comprehensive analyses were performed to evaluate the surface characteristics. • Promising approach for the surface modification of CRS substrate by Ti-based conversion coatings. - Abstract: There have been an increasing interest in finding a replacement for the chromating process due to environmental and health concerns. Hence, in this study Chrome-free chemical conversion coatings were deposited on the surface of cold-rolled steel (CRS) on the basis of Titanium (TiCC), Titanium-Nickel (TiNiCC) and titanium-molybdate (TiMoCC) based conversion coating solutions. The surface characterization was performed by field emission scanning electron microscope (FESEM), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and contact angle measuring device. Also, the corrosion behavior was assessed by the means of potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) measurements. FESEM and AFM study show that the TiNiCC is denser and more uniform than that TiCC and TiMoCC since, TiMoCC conversion coating presents network feature, and there were abundant micro-cracks on the surface of the coating. XPS results confirmed the precipitation of Ti and Ni oxide/hydroxide, Mn dioxide/trioxide on the surface of different Ti-based conversion coatings. Electrochemical results revealed that all Ti-based conversion coatings have better anti-corrosion properties than bare CRS. Moreover, TiNiCC treatment inhibited the corrosion of CRS to a significant degree (polarization resistance (R{sub p}) = 5510 Ω cm{sup 2}) in comparison with TiCC (R{sub p} = 2705 Ω cm{sup 2}) and TiMoCC (R{sub p} = 805 Ω cm{sup 2}).

Electrical conductivity of chromate conversion coating on electrodeposited zinc

International Nuclear Information System (INIS)

Tencer, Michal

2006-01-01

For certain applications of galvanized steel protected with conversion coatings it is important that the surface is electrically conductive. This is especially important with mating surfaces for electromagnetic compatibility. This paper addresses electrical conductivity of chromate conversion coatings. A cross-matrix study using different zinc plating techniques by different labs showed that the main deciding factor is the type of zinc-plating bath used rather than the subsequent chromating process. Thus, chromated zinc plate electrodeposited from cyanide baths is non-conductive while that from alkaline (non-cyanide) and acid baths is conductive, even though the plate from all the bath types is conductive before conversion coating. The results correlate well with the microscopic structure of the surfaces as observed with scanning electron microscopy (SEM) and could be further corroborated and rationalized using EDX and Auger spectroscopies

Preparation of Trivalent Chromium and Rare Earth Composite Conversion Coating on Aluminum Alloy Surface

Science.gov (United States)

Huang, Jianzhen

2018-01-01

In this paper, the surface conversion film on 6063 aluminum alloy was prepared by chemical plating process with chromium sulfate, lanthanum sulfate and sodium phosphate as film forming agent. The corrosion resistance and surface morphology of the conversion film were analyzed by pitting corrosion test of copper sulfate and SEM. The results show that when Cr2(SO4)3 is 10 g/L, La2(SO4)3 is 2 g/L, Na3PO4 is 8 g/L, pH value is 3, temperature is 40 °C, reaction time is 10 min, the corrosion resistance of the surface conversion film is the best. The conversion coating is light green, composed of Cr, La, P, Al, O and other elements.

Growth of permanganate conversion coating on 2024-Al alloy

International Nuclear Information System (INIS)

Kulinich, S.A.; Akhtar, A.S.; Wong, P.C.; Wong, K.C.; Mitchell, K.A.R.

2007-01-01

The growth of permanganate conversion coating on aluminum 2024-T3 alloy has been studied by characterizing, with scanning Auger microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy (XPS) and energy-dispersive X-ray spectroscopy, the coatings formed by immersion of the alloy in the coating bath (containing KMnO 4 and Na 2 B 4 O 7 , pH 9.1) for different periods of time and at different temperatures. At room temperature, during the first 1-5 min of immersion, MnO 2 deposits are formed only on the second-phase intermetallic particles (of Al-Cu-Mg and Al-Cu-Fe-Mn types), but the coating starts to develop on the Al matrix surface after 5-10 min. The coating slows down and stops after about 150 min, with a thinner deposit over the alloy matrix. The process is accelerated at higher temperatures, for example at 68 deg. C it self-limits after about 3 min. The electrochemical growth process appears to follow that established for the chromate conversion coatings, although XPS does not detect significant MnO 4 - incorporation into the permanganate coatings

Protective coatings on structural materials for energy conversion systems

International Nuclear Information System (INIS)

John, J.T.; De, P.K.; Srinivasa, R.S.

2000-01-01

Full text: Structural Materials and Components used in coal fired energy conversion systems, crude oil refineries and coal gasification plants are subjected to degradation due to oxidation, sulfidation, carbonization and halogenation. Suitable protective coatings can significantly enhance their life. Protective coatings work by forming a highly stable, self-healing and slow growing protective scale at the operating temperatures. These scales act as barriers between the corrosive environment and the alloy and prevent degradation of the substitute. Three types of scales that provide such protection are based on Al 2 O 3 , Cr 2 O 3 and SiO 2 . Aluminide coatings are major alumina forming protecting coatings, applied on nickel, cobalt and iron base alloys. Aluminide coatings are prepared by enriching the surface of a component by aluminum. In this paper the formation of aluminide coatings of nickel, IN738, Alloy 800, Zircaloy-2 and pure iron by chemical vapor deposition has been described. In this technique, Aluminum chloride vapors from bath kept at 353-373 K are carried in a stream of hydrogen gas into a Hot Walled CVD chamber kept at 1173-1373 K. The AlCl 3 vapors were allowed to react with pure aluminum whereby aluminum sub-chlorides like AlCl and AlCl 2 are produced which deposit aluminum on the substrates. At the high temperature of the deposition, aluminum diffuses into the substrate and forms the aluminide coating. The process can be represented by the reaction Al (i) + AlCl 3(g) AlCl 2(s) + AlCl 2 (g) . XRD and optical microscopic studies have characterized the coatings. On pure nickel and Alloy 800 the coating consists of Ni 2 Al 3 and NiAl respectively. On pure iron the coatings consisted of FeAl. On Zircaloy-2, ZrAl 2 was also detected. The CVD coating process, XRD and optical microscopy data will be discussed further

Microwave-assisted synthesis of lanthanum conversion coating on Mg-Li alloy and its corrosion resistance

International Nuclear Information System (INIS)

Song Dalei; Jing Xiaoyan; Wang Jun; Lu Shanshan; Yang Piaoping; Wang Yanli; Zhang Milin

2011-01-01

Graphical abstract: Highlights: → The method of microwave is used to synthesize lanthanum conversion coating. → Lanthanum conversion coating on Mg-Li alloy was studied. → Different conditions between room temperature and microwave were compared. → The corrosion behavior of lanthanum conversion coatings was studied. → The corrosion mechanism of lanthanum conversion coatings was studied. - Abstract: Lanthanum-based conversion coating on Mg-Li alloy has been prepared by a microwave-assisted method. X-ray diffractions (XRD) indicate that the intermetallic compounds of lanthanum are formed on Mg-Li alloy surface. Scanning electron microscopy (SEM) images show that the coating has different morphologies and special structures. The corrosion resistance was assessed by means of potentiodynamic polarization curves and electrochemical impedance spectra (EIS). The results indicate that this coating significantly reduces the corrosion rate of Mg-Li alloy in NaCl solution. A comparing experiment indicates that the coating prepared by microwave-assisted process has superior corrosion resistance to the coating obtained at room temperature.

Molybdate/phosphate composite conversion coating on magnesium alloy surface for corrosion protection

International Nuclear Information System (INIS)

Yong Zhiyi; Zhu Jin; Qiu Cheng; Liu Yali

2008-01-01

In this paper, a new conversion coating-molybdate/phosphate (Mo/P) coating on magnesium alloy was prepared and investigated by electrochemical impedance spectra (EIS), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and salt-water immersion experiments, respectively. The results demonstrated that the Mo/P coating contained composite phases, which were consisted of metaphosphate as well as molybdate oxide with an 'alveolate-crystallized' structure. The composite Mo/P conversion coating had better corrosion resistance performance than molybdate (Mo) coating, and even had almost comparable corrosion protection for Mg alloy to the traditional chromate-based coating.

Zr-based conversion coatings for multi-metal substrates

NARCIS (Netherlands)

Cerezo Palacios, J.M.

2015-01-01

In this PhD work, a new surface treatment based on the application of Zr-based conversion coatings by immersion in a Cu containing Zr-based conversion solution was investigated as a replacement of the traditional phosphating process for the automotive industry. Nowadays most of the cars are made of

Corrosion behaviors in physiological solution of cerium conversion coatings on AZ31 magnesium alloy

International Nuclear Information System (INIS)

Cui Xiufang; Yang Yuyun; Liu Erbao; Jin Guo; Zhong Jinggao; Li Qingfen

2011-01-01

In this paper, a non-toxic Ce-based conversion coating was obtained on the surface of bio-medical AZ31 magnesium alloys. The micro-morphology of the coating prepared with optimal technical parameters and immersed in physiological solution (Hank's solution) in different time was observed by scanning electron microscopy (SEM), composition of the cerium conversion coating and corrosion products in Hank's solution were characterized by X-ray photoelectron spectroscopy (XPS) and energy dispersive spectroscopy (EDS), respectively. In addition, the corrosion property in Hank's solution was studied by electrochemical experiment and immersion test. The results show that the dense Ce-based conversion coating is obtained on the surface of AZ31 magnesium alloys in optimal technical parameters and the conversion coating consists of a mass of trivalent and tetravalent cerium oxides. The cerium conversion coating can provide obvious protection of magnesium alloys and can effectively reduce the degradation speed in Hank's solution. Also the degradation products have little influence on human body.

A new type of Ce-Mo based conversion coatings for aluminum alloys

Energy Technology Data Exchange (ETDEWEB)

Li Di; Li Guoqiang; Guo Baolan; Peng Mingxia [Coll. of Materials Science and Engineering, Beijing Univ. of Aeronautics and Astronautics, Beijing, BJ (China)

2002-07-01

A new type of process for forming Ce-Mo conversion coatings on Al-alloys has been developed. Conversion coatings about 3.6 {mu}m thickness were obtained by immersing Al-alloys for 20 minutes in boiling film forming solutions containing (NH{sub 4}){sub 2}Ce(NO{sub 3}){sub 6} 2.5 g/l, NaKC{sub 4}H{sub 4}O{sub 6}.4H{sub 2}O 2.5 g/l, Na{sub 2}CO{sub 3} 7.5 g/l and Na{sub 2}MoO{sub 4} 5.0 g/l. In the case of LF4 Al-alloy, polarization curves and immersion tests in 5% NaCl indicated that the conversion coatings exhibited more excellent resistance to localized corrosion than the conventional chromate conversion coatings. However, its resistance to localized corrosion was not satisfactory on LC4 Al alloy. Scanning electron microscopy (SEM) and energy dispersion analyzer of X-ray (EDAX) analysis revealed that the conversion coatings having complex surface microstructure on both LC4 and LF6 Al alloys consist mainly of O, Al and other alloying elements in addition to significant Ce and Mo. A mechanism of film formation was proposed to explain the experimental results. (orig.)

Evaluation of self-healing ability of Ce–V conversion coating on AZ31 magnesium alloy

Directory of Open Access Journals (Sweden)

Xiao Jiang

2016-09-01

Full Text Available This study investigated the influence of cerium nitrate in vanadate solutions on the properties of Ce–V conversion coatings on AZ31 magnesium alloys, and evaluated the self-healing behavior of the Ce–V conversion coating for AZ31 magnesium alloy. The results showed that the additions of cerium nitrate prevented pentavalent vanadium from reducing to tetravalent vanadium in the coatings during conversion reaction process. Adding appropriate cerium nitrate to vanadate solution led to a thicker coating with a more compact CeVO4 layer. The corrosion behavior of the Ce–V conversion coating was investigated by the electrochemical tests and the scratch immersion test in 3.5 wt.% NaCl solution. The self-healing ability of the coating was confirmed from all tests. The surface analysis revealed that the self-healing effect of the Ce–V conversion coating was only provided by the release and migration of vanadium compounds.

Studies on Chromium-free Conversion coatings on Aluminum | Oki ...

African Journals Online (AJOL)

The development of a chromium-free conversion coating on aluminum has been studied using transmission electron microscopy (TEM), Auger Electron (AES) and Secondary ion mass spectroscopy (SIMS) techniques. Within the limits of the resolution of the TEM, the coating is uniformly clear and featureless. It is composed ...

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%.

Investigation of the chromate conversion coating on Alclad 2024 aluminium alloy: effect of the pH of the chromate bath

NARCIS (Netherlands)

Campestrini, P.; Westing, E.P.M. van; Hovestad, A.; Wit, J.H.W. de

2002-01-01

The parameters of the chromate bath, like temperature, pH, and fluoride content, strongly affect the morphology and chemical composition of the chromate conversion coating and as a consequence have a large influence on its corrosion performance. In this paper, electrochemical impedance spectroscopy

Preparation and properties of chrome-free colored Ti/Zr based conversion coating on aluminum alloy

Energy Technology Data Exchange (ETDEWEB)

Yi Aihua [School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640 (China); Li Wenfang, E-mail: mewfl@scut.edu.cn [School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640 (China); Du Jun; Mu Songlin [School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640 (China)

2012-06-01

A golden conversion coating on the surface of aluminum alloy was prepared by adding tannic acid and coating-forming accelerator in the treatment solution containing titanium and zirconium ions. The growth process, main component and corrosion resistance of the conversion coating were characterized by EDS, SEM, XRD, XPS, FIIR and electrochemical workstation. The results showed that the main components of the conversion coating were Na{sub 3}AlF{sub 6} and the conversion coating owns a double-layer structure. The outer layer consists of metal-organic complex and the inner layer is mainly made up of Na{sub 3}AlF{sub 6}. The mechanism of the formation of the golden conversion coating can be deemed as nucleation, growth of Na{sub 3}AlF{sub 6} crystal and formation of metal-organic complex. In potentiodynamic polarization test, the corrosion current density decreases to 0.283 {mu}A cm{sup -2} from 5.894 {mu}A cm{sup -2}, which indicates an obvious improvement of corrosion resistance.

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.

Friction Modifier Using Adherent Metallic Multilayered or Mixed Element Layer Conversion Coatings

Science.gov (United States)

Schramm, Harry F. (Inventor); Defalco, Francis G. (Inventor); Starks, Lloyd L., Sr. (Inventor)

2013-01-01

A process for creating conversion coatings and spin, drawing, and extrusion finishes for surfaces, wherein the conversion coatings and spin, drawing, and extrusion finishes contain potassium, phosphorus, nitrogen, and one or more non-alkaline metals and/or one or more metalloids. The process comprises forming an aqueous solution of water, phosphoric acid or sulfuric acid, ammonium hydroxide, an alkali metal hydroxide, and one or more non-alkaline metals and/or one or more metalloids. The aqueous solution forms an anti-friction multilayer conversion and/or mixed element coating or a spin, drawing, and extrusion finish on a surface when applied to the surface, either directly without the use of applied external electromotive force, or as an additive in lubricating fluids.

Glass enamel and glass-ceramic coatings for chemical apparatus

International Nuclear Information System (INIS)

Es'kov, A.S.; Oleinik, M.I.; Shabrova, E.A.

1984-01-01

Among the known anticorrosion coatings used in chemical engineering, glass enamel base coatings are distinguished by such advantages as a high degree of continuity and chemical resistance. The paper describes basic principles for the creation of acid and alkali resistant glass enamel and ceramic coatings for chemical apparatus. As the result of investgations, glass enamel coatings with increased electrical conductivity and also experimental production compositions of chemical, temperature and radiation resistant coatings for protection of chemical equipment of 12Kh18N10T stainless steel have been developed. The coatings have successfully passed testing under service conditions. A new type of coating is short-term glass enamel, which may be recommended for use in chemical machinery manufacturing and other branches of industry in oxidation-free heating and forming of stainless steels

Thick sputtered tantalum coatings for high-temperature energy conversion applications

Energy Technology Data Exchange (ETDEWEB)

Stelmakh, Veronika, E-mail: stelmakh@mit.edu; Peykov, Daniel; Chan, Walker R.; Senkevich, Jay J.; Joannopoulos, John D.; Soljačić, Marin; Celanovic, Ivan [Institute for Soldier Nanotechnologies, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Castillo, Robert; Coulter, Kent; Wei, Ronghua [Materials Engineering Department, Southwest Research Institute, San Antonio, Texas 78238 (United States)

2015-11-15

Thick sputtered tantalum (Ta) coatings on polished Inconel were investigated as a potential replacement for bulk refractory metal substrates used for high-temperature emitters and absorbers in thermophotovoltaic energy conversion applications. In these applications, high-temperature stability and high reflectance of the surface in the infrared wavelength range are critical in order to sustain operational temperatures and reduce losses due to waste heat. The reflectance of the coatings (8 and 30 μm) was characterized with a conformal protective hafnia layer as-deposited and after one hour anneals at 700, 900, and 1100 °C. To further understand the high-temperature performance of the coatings, the microstructural evolution was investigated as a function of annealing temperature. X-ray diffraction was used to analyze the texture and residual stress in the coatings at four reflections (220, 310, 222, and 321), as-deposited and after anneal. No significant changes in roughness, reflectance, or stress were observed. No delamination or cracking occurred, even after annealing the coatings at 1100 °C. Overall, the results of this study suggest that the thick Ta coatings are a promising alternative to bulk substrates and pave the way for a relatively low-cost and easily integrated platform for nanostructured devices in high-temperature energy conversion applications.

Effect of heat treatment, top coatings and conversion coatings on the corrosion properties of black electroless Ni-P films

Energy Technology Data Exchange (ETDEWEB)

Liu, Y., E-mail: liu_yunli@hotmail.com [R and D Department, MacDermid plc, 198 Golden Hillock Road, Birmingham B11 2PN (United Kingdom); Beckett, D.; Hawthorne, D. [R and D Department, MacDermid plc, 198 Golden Hillock Road, Birmingham B11 2PN (United Kingdom)

2011-02-15

Electroless black nickel-phosphorus plating is an advanced electroless nickel plating process formulated to deposit a black finish when processed through an oxidizing acid solution. Heat treatment, five types of top organic coating techniques and one conversion coating technique with three different experimental conditions were investigated to stabilize the black film and increase the hardness and corrosion resistance. Morphology and compositions of electroless nickel-phosphorous films with or without heat treatment, with five types of top organic coatings, and with three conversion coatings were compared to examine nickel, phosphorus, oxygen, carbon, silicon and chrome contents on the corrosion resistance of black surfaces by energy dispersive X-ray microanalysis and scanning electron microscope. Corrosion resistance of black electroless nickel-phosphorus coatings with or without heat treatment, with five types of top organic coatings, and with three conversion coatings was investigated by the polarization measurements and the salt spray test in 5% NaCl solution, respectively. HydroLac as the top organic coating from MacDermid showed the excellent corrosion resistance and the black EN film did not lose the black color after 48 h salt spray test. Electrotarnil B process with 0.5 ASD for 1 min stabilized the black Ni-P film immediately and increased the hardness and corrosion performance of the black Ni-P film. The black Ni-P coating with Electroarnil B process passed the 5% NaCl salt spray test for 3000 h in the black color and had a minimal corrosion current 0.8547 {mu}A/cm{sup 2} by the polarization measurement.

Laboratory Validation and Demonstrations of Non-Hexavalent Chromium Conversion Coatings for Steel Substrates (Briefing Charts)

Science.gov (United States)

2011-02-01

UNCLASSIFIED: Approved for public release; distribution unlimited. Laboratory Validation and Demonstrations of Non- Hexavalent Chromium Conversion...00-00-2011 4. TITLE AND SUBTITLE Laboratory Validation and Demonstrations of Non- Hexavalent Chromium Conversion Coatings for Steel Substrates 5a...to MRAP II Acquisition Pretreatment /conversion coatings omitted: • Hex- chrome pretreatments prohibited for new ground vehicles • Hydrogen

Mono-carboxylate conversion coatings for AZ31 Mg alloy protection

Energy Technology Data Exchange (ETDEWEB)

Frignani, A.; Grassi, V.; Zucchi, F.; Zanotto, F. [Corrosion Study Centre A. Dacco, University of Ferrara (Italy)

2011-11-15

Conversion coatings on a magnesium alloy were obtained by dipping AZ31 specimens in aqueous solutions of sodium salts of mono-carboxylic acids (stearic, palmitic, myristic, lauric, mono-carboxylate ion concentration from 1 to 5 mM, depending on the salt solubility) for 24 and 72 h at room temperature, or 24 h at 50 C. The influence exerted by the treatment time, bath temperature and alkyl chain length on the efficiency of these coatings was studied. The performances of the coatings were evaluated by potentiodynamic polarization curve recording after 1 h immersion in 0.05 M Na{sub 2}SO{sub 4} solution, while their temporal evolution was monitored by electrochemical impedance spectroscopy (EIS) spectra during 24 h. Further and long lasting tests were carried out also in 0.1 M NaCl solution. The efficiency of the coatings depended on the aliphatic chain length, and increased as the treatment time and the bath temperature were increased. The coating of lower homologue only hindered the cathodic process, while those of the higher homologues markedly inhibited the anodic process too. The best performances were displayed by 24 h-50 C stearic conversion coating, which maintained a very high efficiency for over 800 h immersion in 0.05 M sulphate solution. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Advanced materials and coatings for energy conversion systems

Energy Technology Data Exchange (ETDEWEB)

St Pierre, George R. [Ohio State Univ., Materials Science and Engineering Dept., Columbus, OH (United States)

1997-12-31

Following an historical review of the development of high-temperature alloys for energy conversion systems including turbine engines, some of the current advances in single crystal materials, intermetallics, metal-matrix composites, and ceramic-matrix composites are discussed. Particular attention is directed at creep phenomena, fatigue properties and oxidation resistance. Included within the discussions is the current status of carbon/carbon composites as potential high-temperature engineering materials and the development of coating systems for thermal barrier and oxidation protection. The specific influences of combustion gas compositions, i.e., oxidation potential, sulfur, halides, etc. are discussed. A current list of eligible advanced materials and coatings systems is presented and assessed. Finally, the critical failure mechanism and life-prediction parameters for some of the new classes of advanced structural materials are elaborated with the view to achieving affordability and extended life with a high degree of reliability. Examples are drawn from a variety of energy conversion systems. (Author)

Corrosion mitigation of rare-earth metals containing magnesium EV31A-T6 alloy via chrome-free conversion coating treatment

International Nuclear Information System (INIS)

Hamdy, Abdel Salam; Butt, Darryl P.

2013-01-01

Highlights: • Protective stannate coatings have been proposed for rare-earth-EV31A-T6 magnesium alloy. • A simple coating method based on direct treatment of EV31A-T6 in a diluted stannate was found promising. • Surface modification prior to stannate coating offer no substantial advantage over directly coating. • Stannate conversion coatings decrease corrosion rates by a factor of 1/7. • The coating does not display any self-healing characteristics as shown in AZ91D. -- Abstract: Magnesium alloys posses unique mechanical and physical characteristics making them attractive light-weight materials for several strategic industries such as electronics, computer, automotive and aerospace. Due to their high chemical reactivity and poor corrosion resistance, the protection of magnesium alloys from corrosion is one of the hottest topics in materials science and engineering. Addition of rare-earth metals (RE) as alloying elements to magnesium alloys is one of the common approaches to improve their mechanical properties and, sometimes, the corrosion resistance. However, the potential difference between the RE metals phase formed in the Mg matrix enhances the galvanic corrosion at the interfaces where RE metals inert phase acts as cathode and the active Mg matrix acts as anode. This paper introduces a simple one-step clean conversion coating treatment for improving the protection of RE containing magnesium EV31A-T6 alloy in Cl − media

Chemical vapor deposited fiber coatings and chemical vapor infiltrated ceramic matrix composites

Energy Technology Data Exchange (ETDEWEB)

Kmetz, M.A.

1992-01-01

Conventional Chemical Vapor Deposition (CVD) and Organometallic Chemical Vapor Deposition (MOCVD) were employed to deposit a series of interfacial coatings on SiC and carbon yarn. Molybdenum, tungsten and chromium hexacarbonyls were utilized as precursors in a low temperature (350[degrees]C) MOCVD process to coat SiC yarn with Mo, W and Cr oxycarbides. Annealing studies performed on the MoOC and WOC coated SiC yarns in N[sub 2] to 1,000[degrees]C establish that further decomposition of the oxycarbides occurred, culminating in the formation of the metals. These metals were then found to react with Si to form Mo and W disilicide coatings. In the Cr system, heating in N[sub 2] above 800[degrees]C resulted in the formation of a mixture of carbides and oxides. Convention CVD was also employed to coat SiC and carbon yarn with C, Bn and a new interface designated BC (a carbon-boron alloy). The coated tows were then infiltrated with SiC, TiO[sub 2], SiO[sub 2] and B[sub 4]C by a chemical vapor infiltration process. The B-C coatings were found to provide advantageous interfacial properties over carbon and BN coatings in several different composite systems. The effectiveness of these different coatings to act as a chemically inert barrier layer and their relationship to the degree of interfacial debonding on the mechanical properties of the composites were examined. The effects of thermal stability and strength of the coated fibers and composites were also determined for several difference atmospheres. In addition, a new method for determining the tensile strength of the as-received and coated yarns was also developed. The coated fibers and composites were further characterized by AES, SEM, XPS, IR and X-ray diffraction analysis.

The role of phosphate conversion coatings in make-up of casing connections

NARCIS (Netherlands)

Ernens, D; van Riet, E.J.; de Rooij, M.B.; Pasaribu, H.R.; van Haaften, W.M.; Schipper, D.J.

2017-01-01

Phosphate conversion coatings are widely used on (premium) casing connections for protection against corrosion. Next to that, in conjunction with the lubricant these coatings provide galling protection. The friction and wear that occurs during make-up and subsequent load cycling determines the

Optimization of process factors for self-healing vanadium-based conversion coating on AZ31 magnesium alloy

Energy Technology Data Exchange (ETDEWEB)

Li, Kun; Liu, Junyao [State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China); Lei, Ting, E-mail: tlei@mail.csu.edu.cn [State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China); Xiao, Tao [2nd Xiangya Hospital, Central South University, Changsha 410011 (China)

2015-10-30

Highlights: • The optimum operating conditions were determined by an orthogonal experiment. • The coating is composed of oxides and hydroxides of V{sup 5+}, V{sup 4+} and Mg(OH){sub 2}. • The self-healing performance was investigated by cross-cut immersion test. • The vanadia conversion coating provided active corrosion protection to AZ31 alloy. - Abstract: A self-healing vanadium-based conversion coating was prepared on AZ31 magnesium alloy. The optimum operating conditions including vanadia solution concentration, pH and treating temperature for obtaining the best corrosion protective vanadia coatings and improved localized corrosion resistance to the magnesium substrate were determined by an orthogonal experiment design. Surface morphology and composition of the resultant conversion coatings were investigated by scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). The self-healing behavior of the coating was investigated by cross-cut immersion test and electrochemical impedance spectroscopy (EIS) measurements in 3.5% NaCl solution.

Optimization of process factors for self-healing vanadium-based conversion coating on AZ31 magnesium alloy

International Nuclear Information System (INIS)

Li, Kun; Liu, Junyao; Lei, Ting; Xiao, Tao

2015-01-01

Highlights: • The optimum operating conditions were determined by an orthogonal experiment. • The coating is composed of oxides and hydroxides of V"5"+, V"4"+ and Mg(OH)_2. • The self-healing performance was investigated by cross-cut immersion test. • The vanadia conversion coating provided active corrosion protection to AZ31 alloy. - Abstract: A self-healing vanadium-based conversion coating was prepared on AZ31 magnesium alloy. The optimum operating conditions including vanadia solution concentration, pH and treating temperature for obtaining the best corrosion protective vanadia coatings and improved localized corrosion resistance to the magnesium substrate were determined by an orthogonal experiment design. Surface morphology and composition of the resultant conversion coatings were investigated by scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). The self-healing behavior of the coating was investigated by cross-cut immersion test and electrochemical impedance spectroscopy (EIS) measurements in 3.5% NaCl solution.

Solar energy conversion. Chemical aspects

Energy Technology Data Exchange (ETDEWEB)

Likhtenshtein, Gertz [Ben-Gurion Univ. of the Negev, Beersheba (Israel). Dept. of Chemistry

2012-07-01

Finally filling a gap in the literature for a text that also adopts the chemist's view of this hot topic, Professor Likhtenshtein, an experienced author and internationally renowned scientist, considers different physical and engineering aspects in solar energy conversion. From theory to real-life systems, he shows exactly which chemical reactions take place when converting light energy, providing an overview of the chemical perspective from fundamentals to molecular harvesting systems and solar cells. This essential guide will thus help researchers in academia and industry better understand solar energy conversion, and so ultimately help this promising, multibillion euro/dollar field to expand. (orig.)

The effects of addition of poly(vinyl) alcohol (PVA) as a green corrosion inhibitor to the phosphate conversion coating on the anticorrosion and adhesion properties of the epoxy coating on the steel substrate

Energy Technology Data Exchange (ETDEWEB)

Ramezanzadeh, B., E-mail: ramezanzadeh-bh@icrc.ac.ir; Vakili, H.; Amini, R.

2015-02-01

Highlights: • Room temperature zinc phosphate coating was applied on the surface of steel sample. • Poly(vinyl) alcohol was added to the phosphating bath as a green corrosion inhibitor. • The adhesion and anticorrosion properties of the epoxy coating were investigated. • PVA decreased the phosphate crystal size and porosity. • PVA enhanced the corrosion protection and adhesion properties of the epoxy coating. - Abstract: Steel substrates were chemically treated by room temperature zinc phosphate conversion coating. Poly(vinyl) alcohol (PVA) was added to the phosphate solution as a green corrosion inhibitor. Finally, the epoxy/polyamide coating was applied on the untreated and surface treated steel samples. The effects of PVA on the morphological properties of the phosphate coating were studied by scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS) and contact angle measuring device. The adhesion properties of the epoxy coatings applied on the surface treated samples were investigated by pull-off and cathodic delamination tests. Also, the anticorrosion properties of the epoxy coatings were studied by electrochemical impedance spectroscopy (EIS). Results showed that addition of PVA to the phosphate coating increased the population density of the phosphate crystals and decreased the phosphate grain size. The contact angle of the steel surface treated by Zn-PVA was lower than Zn treated one. The corrosion resistance of the epoxy coating was considerably increased on the steel substrate treated by zinc phosphate conversion coating containing PVA. PVA also enhanced the adhesion properties of the epoxy coating to the steel surface and decreased the cathodic delamination significantly.

Self-healing Li-Al layered double hydroxide conversion coating modified with aspartic acid for 6N01 Al alloy

International Nuclear Information System (INIS)

Zhang, Caixia; Luo, Xiaohu; Pan, Xinyu; Liao, Liying; Wu, Xiaosong; Liu, Yali

2017-01-01

Highlights: • A self-healing chrome-free Li-Al layered double hydroxide conversion coating modified with Aspartic acid was prepared. • One-step conversion coating formed by simple immersion in a conversion solution for a short time and a low temperature. • The conversion coating had excellent corrosion resistance. • The possible mechanism via exchange/self-assembly of the conversion coating was proposed in this paper. - Abstract: A self-healing Li-Al layered double hydroxide conversion coating (LCC) modified with aspartic acid (ALCC) was prepared on 6N01 Al alloy for corrosion protection. Scanning electron microscopy (SEM) showed that a compact thin film has been successfully formed on the alloy. X-ray diffraction (XRD) and FT-IR spectra proved that species of aspartic acid anions were successfully intercalated into LCC. Potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and neutral salt spray (NSS) testing showed that the resultant ALCC could provide effective corrosion protection for the Al alloy. During immersion of the ALCC-coated alloy in 3.5% NaCl solution, new film was formed in the area of artificially introduced scratch, indicating its self-healing capability. XPS results demonstrated that Cl- anions exchange partial Asp anions according to the change content of element on conversion coating. From the above results, the possible mechanism via exchange/self-assembly was proposed to illustrate the phenomenon of self-healing.

Self-healing Li-Al layered double hydroxide conversion coating modified with aspartic acid for 6N01 Al alloy

Energy Technology Data Exchange (ETDEWEB)

Zhang, Caixia; Luo, Xiaohu; Pan, Xinyu; Liao, Liying; Wu, Xiaosong; Liu, Yali, E-mail: yaliliu@hnu.edu.cn

2017-02-01

Highlights: • A self-healing chrome-free Li-Al layered double hydroxide conversion coating modified with Aspartic acid was prepared. • One-step conversion coating formed by simple immersion in a conversion solution for a short time and a low temperature. • The conversion coating had excellent corrosion resistance. • The possible mechanism via exchange/self-assembly of the conversion coating was proposed in this paper. - Abstract: A self-healing Li-Al layered double hydroxide conversion coating (LCC) modified with aspartic acid (ALCC) was prepared on 6N01 Al alloy for corrosion protection. Scanning electron microscopy (SEM) showed that a compact thin film has been successfully formed on the alloy. X-ray diffraction (XRD) and FT-IR spectra proved that species of aspartic acid anions were successfully intercalated into LCC. Potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and neutral salt spray (NSS) testing showed that the resultant ALCC could provide effective corrosion protection for the Al alloy. During immersion of the ALCC-coated alloy in 3.5% NaCl solution, new film was formed in the area of artificially introduced scratch, indicating its self-healing capability. XPS results demonstrated that Cl- anions exchange partial Asp anions according to the change content of element on conversion coating. From the above results, the possible mechanism via exchange/self-assembly was proposed to illustrate the phenomenon of self-healing.

Optimization of process factors for self-healing vanadium-based conversion coating on AZ31 magnesium alloy

Science.gov (United States)

Li, Kun; Liu, Junyao; Lei, Ting; Xiao, Tao

2015-10-01

A self-healing vanadium-based conversion coating was prepared on AZ31 magnesium alloy. The optimum operating conditions including vanadia solution concentration, pH and treating temperature for obtaining the best corrosion protective vanadia coatings and improved localized corrosion resistance to the magnesium substrate were determined by an orthogonal experiment design. Surface morphology and composition of the resultant conversion coatings were investigated by scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). The self-healing behavior of the coating was investigated by cross-cut immersion test and electrochemical impedance spectroscopy (EIS) measurements in 3.5% NaCl solution.

Effects of combined organic and inorganic corrosion inhibitors on the nanostructure cerium based conversion coating performance on AZ31 magnesium alloy: Morphological and corrosion studies

International Nuclear Information System (INIS)

Saei, E.; Ramezanzadeh, B.; Amini, R.; Kalajahi, M. Salami

2017-01-01

Highlights: •Cn-Mn-polyvinyl alcohol conversion coating led to more uniform and crack free film deposition. •The corrosion resistance of Ce film was noticeably improved by using combination of polyvinyl alchol and Mn2+ cations. •A synergistic effect between polyvinyl alchol-Mn2+ resulted in Ce film with enhanced morphology and corrosion resistance. -- Abstract: Magnesium (Mg) AZ31 samples were chemically treated by a series of room temperature nanostructure cerium based conversion coatings containing Mn(NO 3 ) 2 ·4H 2 O, Co(NO 3 ) 2 ·6H 2 O, and polyvinyl alcohol (PVA). The microstructure and corrosion protection properties of different samples were studied by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS) and polarization test in 3.5 wt.% NaCl solution. Results demonstrated that the AZ31 Mg alloy sample treated by Ce-Mn-PVA showed the highest corrosion resistance. A denser Ce film with lower crack was precipitated on the sample treated by Ce-Mn-PVA conversion coating.

An environment-friendly phosphate chemical conversion coating on novel Mg-9Li-7Al-1Sn and Mg-9Li-5Al-3Sn-1Zn alloys with remarkable corrosion protection

Science.gov (United States)

Maurya, Rita; Siddiqui, Abdul Rahim; Balani, Kantesh

2018-06-01

An environment-friendly phosphate chemical conversion (PCC) coating has been deposited on novel LAT971 (Mg-9 wt%Li-7 wt%Al-1 wt%Sn) and LATZ9531 (Mg-9 wt%Li-5 wt%Al-3 wt%Sn-1 wt%Zn) alloys for improving their corrosion resistance. A dense and homogeneous flower like morphology (∼30 μm thick) was observed on the PCC coated Mg-Li based alloys. The presence of calcium hydrogen phosphate hydrate, tricalcium phosphate and trimagnesium phosphate were confirmed from the X-ray diffraction and X-ray photoelectron spectroscopy analysis. A lower corrosion current density of 6.74 × 10-7 mA/cm2 and 5.39 × 10-7 mA/cm2 was obtained for PCC coated alloys in 3.5% NaCl aqueous solution than that of uncoated LAT971 (0.82 mA/cm2) and LATZ9531 (0.34 mA/cm2) alloys, respectively, which offers corrosion protection efficiency of >99%. Electrochemical impedance spectroscopy (EIS) has revealed that the inner PCC coating (at coating/substrate interface) delay the direct contact between electrolyte and substrate, which offered higher charge transfer resistance (>4 orders of magnitude) than that of uncoated alloys. Thus, the PCC coating provides an effective corrosion protection to the ultra-lightweight LAT971 and LATZ9531 alloys surface and may be helpful in proving good anchoring with the top organic coatings or paints.

The role of hexafluorozirconate in the formation of chromate conversion coatings on aluminum alloys

International Nuclear Information System (INIS)

Chidambaram, Devicharan; Clayton, Clive R.; Halada, Gary P.

2006-01-01

Aluminum based surfaces are routinely coated with a chromate based layer that provides unparalleled corrosion protection. Widely used conversion coating treatment formulations contain hexafluorozirconate as a major constituent besides chromate, ferricyanide, fluoride, and fluoborate. The function of hexafluorozirconate is the subject of this study as its function is still largely unknown. Hydrophobicity, surface morphology, and the chemistry of the surface, resulting from treatment with hexafluorozirconate, were studied using contact angle measurements, scanning electron microscopy, and energy dispersive spectroscopy, respectively. X-ray photoelectron spectroscopy was extensively utilized to determine the chemistry of the surface resulting from the hexafluorozirconate pretreatment. Our results indicate that fluoride ion containing hexafluorozirconate complex does not attack the oxide film in a manner that uncomplexed simple fluoride ion does. Hexafluorozirconate is involved in the formation of an Al-Zr-O-F based hydrated layer that increases the hydrophilicity of the surface, activates the surface, and lowers the corrosion resistance. These factors enhance the interaction of chromate with the alloy surface to result in the formation of a uniform conversion coating. Based on these results, a new model has been proposed for the formation of chromate conversion coatings

A Black Phosphate Conversion Coating on Steel Surface Using Antimony(III)-Tartrate as an Additive

Science.gov (United States)

Li, Feng; Wang, Guiping

2016-05-01

A novel black phosphate conversion coating was formed on steel surface through a Zn-Mn phosphating bath containing mainly ZnO, H3PO4, Mn(H2PO4)2, and Ca(NO3)2, where antimony(III)-tartrate was used as the blackening agent of phosphatization. The surface morphology and composition of the coating were characterized by scanning electron microscopy, energy dispersion spectroscopy, and x-ray photoelectron spectroscopy. Corrosion resistance of the coating was studied by potentiodynamic polarization curves and electrochemical impedance spectroscopy. The pH value of the solution had significant influence on the formation and corrosion resistance of the coating. The experimental results indicated that the Sb plays a vital role in the blackening of phosphate conversion coating. The optimal concentration of antimony(III)-tartrate in the phosphating bath used in this experiment was 1.0 g L-1, as higher values reduced the corrosion resistance of the coating. In addition, by saponification and oil seals, the corrosion duration of the black phosphate coating in a copper sulfate spot test can be as long as 20 min.

Zr-based conversion layer on Zn-Al-Mg alloy coated steel sheets: insights into the formation mechanism

International Nuclear Information System (INIS)

Lostak, Thomas; Maljusch, Artjom; Klink, Björn; Krebs, Stefan; Kimpel, Matthias; Flock, Jörg; Schulz, Stephan; Schuhmann, Wolfgang

2014-01-01

Zr-based conversion layers are considered as environmentally friendly alternatives replacing trication phosphatation in the automotive industry. Based on excellent electronic barrier properties they provide an effective corrosion protection of the metallic substrate. In this work, thin protective layers were grown on novel Zn-Al-Mg alloy coated steel sheets by increasing the local pH-value at the sample surface leading to deposition of a Zr-based conversion layer. For this purpose Zn-Al-Mg alloy (ZM) coated steel sheets were treated in an aqueous model conversion solution containing well-defined amounts of hexafluorozirconic acid (H 2 ZrF 6 ) and characterized after different immersion times with SKPFM and field emission SEM (FE-SEM)/EDX techniques. A deposition mechanism of Zr-based conversion coatings on microstructural heterogeneous Zn-Al-Mg alloy surfaces was proposed

Lanthanide based conversion coatings for long term wet storage of aluminium-clad spent fuel

International Nuclear Information System (INIS)

Fernandes, S.M.C.; Correa, O.V.; De Souza, J.A.; Ramanathan, L.V.

2010-01-01

Spent fuels from research reactors are stored in basins with water of less than desirable quality at many facilities around the world and instances of cladding failure caused by pitting corrosion have been reported. Conversion coatings have been used in many industries to protect different metals, including aluminium alloys. This paper presents the results of an ongoing investigation in which the corrosion resistance of lanthanide (cerium, lanthanum and praseodymium) based conversion coated RR fuel cladding alloys has been studied. Electrochemical tests in the laboratory revealed higher corrosion resistance of CeO 2 , La 2 O 3 and Pr 2 O 3 coated AA 1100 and AA 6061 alloys in NaCl solutions. Uncoated and CeO 2 coated coupons of these alloys exposed for 50 days to the spent fuel basin of the IEA-R1 research reactor in IPEN, Brazil, revealed marked reductions in the extent of pitting corrosion. (author)

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.

Energy conversion technology by chemical processes

Energy Technology Data Exchange (ETDEWEB)

Oh, I W; Yoon, K S; Cho, B W [Korea Inst. of Science and Technology, Seoul (Korea, Republic of); and others

1996-12-01

The sharp increase in energy usage according to the industry development has resulted in deficiency of energy resources and severe pollution problems. Therefore, development of the effective way of energy usage and energy resources of low pollution is needed. Development of the energy conversion technology by chemical processes is also indispensable, which will replace the pollutant-producing and inefficient mechanical energy conversion technologies. Energy conversion technology by chemical processes directly converts chemical energy to electrical one, or converts heat energy to chemical one followed by heat storage. The technology includes batteries, fuel cells, and energy storage system. The are still many problems on performance, safety, and manufacturing of the secondary battery which is highly demanded in electronics, communication, and computer industries. To overcome these problems, key components such as carbon electrode, metal oxide electrode, and solid polymer electrolyte are developed in this study, followed by the fabrication of the lithium secondary battery. Polymer electrolyte fuel cell, as an advanced power generating apparatus with high efficiency, no pollution, and no noise, has many applications such as zero-emission vehicles, on-site power plants, and military purposes. After fabricating the cell components and operating the single cells, the fundamental technologies in polymer electrolyte fuel cell are established in this study. Energy storage technology provides the safe and regular heat energy, irrespective of the change of the heat energy sources, adjusts time gap between consumption and supply, and upgrades and concentrates low grade heat energy. In this study, useful chemical reactions for efficient storage and transport are investigated and the chemical heat storage technology are developed. (author) 41 refs., 90 figs., 20 tabs.

Chromium-free conversion coatings based on inorganic salts (Zr/Ti/Mn/Mo) for aluminum alloys used in aircraft applications

Energy Technology Data Exchange (ETDEWEB)

Santa Coloma, P., E-mail: patricia.santacoloma@tecnalia.com [TECNALIA Research & Innovation, Parque Tecnológico de San Sebastián, Mikeletegi Pasealekua 2, E-20009 Donostia-San Sebastián, Gipuzkoa (Spain); Izagirre, U.; Belaustegi, Y.; Jorcin, J.B.; Cano, F.J. [TECNALIA Research & Innovation, Parque Tecnológico de San Sebastián, Mikeletegi Pasealekua 2, E-20009 Donostia-San Sebastián, Gipuzkoa (Spain); Lapeña, N. [Boeing Research & Technology Europe, S.L.U., Avenida Sur del Aeropuerto de Barajas 38, Building 4 – 3rd Floor, E-28042 Madrid (Spain)

2015-08-01

Highlights: • Chromium-free conversion coatings for corrosion protection of aluminum alloys. • Salt spray and potentiodynamic sweep tests to study the corrosion behavior. • Local deposits on Cu-rich intermetallic particles enhanced corrosion resistance. • Surface characterization to relate bath's composition and corrosion resistance. • Best corrosion protection with conversion baths without titanium salts. - Abstract: Novel chromium-free conversion coatings based on Zr/Ti/Mn/Mo compounds were developed at a pilot scale to improve the corrosion resistance of the AA2024-T3 and AA7075-T6 aluminum alloys for aircraft applications. The influence of the presence of Zr and Ti in the Zr/Ti/Mn/Mo conversion bath's formulation on the corrosion resistance of the coated alloys was investigated. The corrosion resistance provided by the conversion coatings was evaluated by salt spray exposure and potentiodynamic sweeps. Optical and scanning electron microscopy coupled with energy dispersive spectroscopy (SEM/EDS) and atomic force microscopy (AFM) operating in the Kelvin Probe mode (SKPFM) were used to provide microstructural information of the coated samples that achieved the best results in the corrosion tests. The salt spray test evidenced the higher corrosion resistance of the coated samples compared to the bare surfaces for both alloys. The potentiodynamic tests showed that the corrosion current density decreased for coated AA7075-T6 and AA2024-T3 alloys, which indicated an obvious improvement of the corrosion resistance with all the processes for both alloys. Although the corrosion resistance of the coated samples appeared to be higher for the alloy AA7075-T6 than for the alloy AA2024-T3, both alloys achieved the best corrosion protection with the coatings deposited from conversion bath formulations containing no titanium salts. The microscopy analysis on the coated AA7075-T6 samples revealed that a local deposition of Zr compounds and, possibly, an

Chromium-free conversion coatings based on inorganic salts (Zr/Ti/Mn/Mo) for aluminum alloys used in aircraft applications

International Nuclear Information System (INIS)

Santa Coloma, P.; Izagirre, U.; Belaustegi, Y.; Jorcin, J.B.; Cano, F.J.; Lapeña, N.

2015-01-01

Highlights: • Chromium-free conversion coatings for corrosion protection of aluminum alloys. • Salt spray and potentiodynamic sweep tests to study the corrosion behavior. • Local deposits on Cu-rich intermetallic particles enhanced corrosion resistance. • Surface characterization to relate bath's composition and corrosion resistance. • Best corrosion protection with conversion baths without titanium salts. - Abstract: Novel chromium-free conversion coatings based on Zr/Ti/Mn/Mo compounds were developed at a pilot scale to improve the corrosion resistance of the AA2024-T3 and AA7075-T6 aluminum alloys for aircraft applications. The influence of the presence of Zr and Ti in the Zr/Ti/Mn/Mo conversion bath's formulation on the corrosion resistance of the coated alloys was investigated. The corrosion resistance provided by the conversion coatings was evaluated by salt spray exposure and potentiodynamic sweeps. Optical and scanning electron microscopy coupled with energy dispersive spectroscopy (SEM/EDS) and atomic force microscopy (AFM) operating in the Kelvin Probe mode (SKPFM) were used to provide microstructural information of the coated samples that achieved the best results in the corrosion tests. The salt spray test evidenced the higher corrosion resistance of the coated samples compared to the bare surfaces for both alloys. The potentiodynamic tests showed that the corrosion current density decreased for coated AA7075-T6 and AA2024-T3 alloys, which indicated an obvious improvement of the corrosion resistance with all the processes for both alloys. Although the corrosion resistance of the coated samples appeared to be higher for the alloy AA7075-T6 than for the alloy AA2024-T3, both alloys achieved the best corrosion protection with the coatings deposited from conversion bath formulations containing no titanium salts. The microscopy analysis on the coated AA7075-T6 samples revealed that a local deposition of Zr compounds and, possibly, an

Conversion electron Moessbauer spectroscopic studies on the chemical states of surface layers of corroded tin plates and tin-coated iron plates

International Nuclear Information System (INIS)

Kato, Akinori; Endo, Kazutoyo; Sano, Hirotoshi

1980-01-01

By means of the conversion electron Moessbauer spectroscopy (CEMS), we studied surface layers of ''tin'' plates and tin-coated iron plates corroded by various acids. Transmission Moessbauer spectra and X-ray diffraction patterns were also measured. Metastannic acid was formed, when the ''tin'' plate was corroded by nitric acid solution. In corrosion by phosphoric acid solution, the X-ray diffractometry revealed the formation of tin(IV) pyrophosphate. In corrosion by various organic acid solutions, the formation of oxides was identified by the 119 Sn CEMS, but not by the X-ray diffractometry because of the too thin corrosion layer. In corrosion of tin-coated iron plates, maleic acid, malonic acid, formic acid, and oxalic acid were used. It was determined by CEMS that the corrosion products caused by these acids were tin(IV) oxides, although they could not be identified by the X-ray diffractometry. CEMS also confirmed that the surface of uncorroded tin-coated iron plate was already oxidized by air. Colorimetric determinations of Sn and Fe dissolved from tin-coated iron plates to various acid solutions confirmed that maleic acid had the strongest corrosion effect among the organic acids studied. (author)

Fabrication of silica-coated gold nanorods and investigation of their property of photothermal conversion

International Nuclear Information System (INIS)

Inose, Tomoya; Oikawa, Takahiro; Shibuya, Kyosuke; Tokunaga, Masayuki; Hatoyama, Keiichiro; Nakashima, Kouichi; Kamei, Takashi; Gonda, Kohsuke; Kobayashi, Yoshio

2017-01-01

This study described the preparation of silica-coated Au nanorods (AuNR/SiO 2 ) in a colloidal solution, assessed their property of photothermal conversion, and investigated their ability to kill cancer cells using photothermal conversion. Au-seed nanoparticles were produced by reducing hydrogen tetrachloroaurate (HAuCl 4 ) with sodium borohydride (NaBH 4 ) in aqueous n-hexadecyltrimethylammonium bromide (CTAB) solution. AuNRs were then fabricated by reducing HAuCl 4 and silver nitrate (AgNO 3 ) with L-ascorbic acid in the aqueous CTAB solution in the presence of Au-seed nanoparticles. The as-prepared AuNRs were washed by a process composed mainly of centrifugation to remove the CTAB. The washed AuNRs were coated with silica by mixing the AuNR colloidal solution, an aqueous solution of (3-aminopropyl)trimethoxysilane, and tetraethylorthosilicate/ethanol solution with a water/ethanol solution. We found that the addition of AuNR/SiO 2 in water, in mice, and in a culture medium with cancer cells, followed by irradiation with a laser, cause an increase in temperature, demonstrating that AuNR/SiO 2 have the ability of photothermal conversion. In addition, the cancer cells in the culture medium were found to be killed due to the increase in temperature caused by the photothermal conversion. - Highlights: • This study described the preparation of silica-coated Au nanorods (AuNR/SiO 2 ) colloidal solution. • The AuNR/SiO 2 had the ability of photothermal conversion. • The AuNR/SiO 2 also had the ability to kill cancer cells using the photothermal conversion.

Corrosion of chromatic conversion coatings on Aluminium Alloys in electrical and electronic equipment

International Nuclear Information System (INIS)

Razavi, R.Sh.; Shahrabi, T.; Mozafarnia, R.

2002-01-01

Chromate conversion coating is applied on aluminum 6061. The optimum conditions for chromate bath composition and immersion time are also obtained for standard requirements provision such as corrosion resistance in salt spray test, electrical resistance and coating quality. The applied coatings are electrochemically tested in sea and distilled water. According to Tafel and cyclic polarization curves, the protection mechanism are evaluated in said environments. This evaluation has shown the formation of passive film layer, contains chromate and alumina on the base. The proper behavior of corrosion and electrical conductivity is probably due to this mechanism

Physico-chemical and thermochemical studies of the hydrolytic conversion of amorphous tricalcium phosphate into apatite

International Nuclear Information System (INIS)

Somrani, Saida; Banu, Mihai; Jemal, Mohamed; Rey, Christian

2005-01-01

The conversion of amorphous tricalcium phosphate with different hydration ratio into apatite in water at 25 deg. C has been studied by microcalorimetry and several physical-chemical methods. The hydrolytic transformation was dominated by two strong exothermic events. A fast, relatively weak, wetting process and a very slow but strong heat release assigned to a slow internal rehydration and the crystallization of the amorphous phase into an apatite. The exothermic phenomenon related to the rehydration exceeded the crystalline transformation enthalpy. Rehydration occurred before the conversion of the amorphous phase into apatite and determined the advancement of the hydrolytic reaction. The apatitic phases formed evolved slightly with time after their formation. The crystallinity increased whereas the amount of HPO 4 2- ion decreased. These data allow a better understanding of the behavior of biomaterials involving amorphous phases such as hydroxyapatite plasma-sprayed coatings

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.)

Inhibition of the corrosion of mild steel by phosphate conversion coatings

International Nuclear Information System (INIS)

Ashraf, W.; Khalid, S.; Rashid, A.; Arshad, M.

1993-01-01

Phosphating is the treatment of a metal surface to provide a coating of insoluble metal phosphate crystals which strongly adhere to the base material. Such coatings affect the appearance, surface hardness, and electrical conductivity of the metal. Phosphating is major industrial importance in the production of iron and steel surfaces, e.g., in automotive and appliance industries. The present article discusses a novel description of process controlling parameters. The process may be termed as hot phosphate (95-100 deg. C) and it employs the use of low cost chemicals and entirely new accelerator. Effective layer thickness is found to be 0.72 mg/cm /sup 2/ and can withstand moist and mild chemical conditions. The thickness of coating depends upon dipping time and temperature of the working bath. It seems to increase with increasing dipping time but then reaches a maxima. Any more dipping causes stripping and uneven coating layers. In our system most appropriate dipping time was found to be 45 minutes. The stability and completeness of coating was tested by Ferro Test and Tape Pull Test and was found to be satisfactory. The quality control parameters, such as free and total acidity have been controlled for optimum coating thickness and stability. (author)

On the growth of conversion chromate coatings on 2024-Al alloy

International Nuclear Information System (INIS)

Kulinich, S.A.; Akhtar, A.S.; Susac, D.; Wong, P.C.; Wong, K.C.; Mitchell, K.A.R.

2007-01-01

The initial growth of chromate conversion coatings on aluminium 2024-T3 alloy has been investigated by scanning Auger microscopy, scanning electron microscopy and X-ray photoelectron spectroscopy. The coating initiation is shown to be influenced by the alloy microstructure. In agreement with previously proposed growth models, Cr(VI) to Cr(III) reduction begins on the Al-Cu-Fe-Mn intermetallic second-phase particles, which act as cathodic sites, and then over the entire Al matrix surface. The less noble Al-Cu-Mg second-phase particles demonstrate dual behaviour during the initial stage of coating; some dealloy, with formation of a Cu-rich sponge-like structure, while others show no evidence for etching during the first few seconds and coating deposits on them similar to the situation for the Al-Cu-Fe-Mn particles. XPS measurements show more Cr(III) at the very initial stage of nucleation and growth, whereas the amount of Cr(VI) in the coating increases with the length of the chromating treatment. This is discussed in relation to Raman spectroscopy measurements made in a separate study

Acid-resistant organic coatings for the chemical industry: a review

DEFF Research Database (Denmark)

Møller, Victor Buhl; Dam-Johansen, Kim; Frankær, Sarah Maria Grundahl

2017-01-01

Industries that work with acidic chemicals in their processes need to make choices on how to properly contain the substances and avoid rapid corrosion of equipment. Certain organic coatings and linings can be used in such environments, either to protect vulnerable construction materials, or......, in combination with fiber reinforcement, to replace them. However, degradation mechanisms of organic coatings in acid service are not thoroughly understood and relevant quantitative investigations are scarce. This review describes the uses and limitations of acid-resistant coatings in the chemical industry...

Effects of vacuum and ageing on Zr4/Cr3 based conversion coatings on aluminium alloys

Science.gov (United States)

Thirupathi, Kalaivanan; Bárczy, Pál; Vad, Kálmán; Csik, Attila; Somosvári, Béla Márton

2018-05-01

In this study, we investigate the impact of ageing and high vacuum on existing environmentally friendly Zr4/Cr3-based conversion coatings. The freshly formed coating undergoes several changes during ageing and exposure to high vacuum. Based on the present data, we propose that the coating formed over AA6082 and AA7075 alloys is sol-gel in nature, confirmed by secondary neutral mass spectroscopy (SNMS) using the depth profiling technique. Our findings reveal that there are elemental level changes that result in shrinkage of the coating. Most Zr ions in the coating are in the solute form, with lesser number of Cr and Al ions that disappear under high vacuum over a certain period of time. The remaining Cr, Zr and O atoms exist in a gelatinous state. During ageing, there is a continuous transition of ions from solute to gelatinous state. In addition, the deposition of coating ions is directly influenced by the substrates and their constituents. The extent of dissolution of aluminium in the conversion bath determines both Zr and Cr ion deposition. For a highly alloyed metal like AA7075, the dissolution rate is disturbed by copper and zinc.

Forensic collection of trace chemicals from diverse surfaces with strippable coatings.

Science.gov (United States)

Jakubowski, Michael J; Beltis, Kevin J; Drennan, Paul M; Pindzola, Bradford A

2013-11-07

Surface sampling for chemical analysis plays a vital role in environmental monitoring, industrial hygiene, homeland security and forensics. The standard surface sampling tool, a simple cotton gauze pad, is failing to meet the needs of the community as analytical techniques become more sensitive and the variety of analytes increases. In previous work, we demonstrated the efficacy of non-destructive, conformal, spray-on strippable coatings for chemical collection from simple glass surfaces. Here we expand that work by presenting chemical collection at a low spiking level (0.1 g m(-2)) from a diverse array of common surfaces - painted metal, engineering plastics, painted wallboard and concrete - using strippable coatings. The collection efficiency of the strippable coatings is compared to and far exceeds gauze pads. Collection from concrete, a particular challenge for wipes like gauze, averaged 73% over eight chemically diverse compounds for the strippable coatings whereas gauze averaged 10%.

Application of mechano-chemical synthesis for protective coating

Indian Academy of Sciences (India)

This can either be prevented by using grinding medium and container of same material of the milled material or by adding a coating of the milled material on them. The paper describes the observations made during a mechano-chemical reaction, being used for coating the balls and vials in a planetary ball mill.

Zeolite-catalyzed biomass conversion to fuels and chemicals

DEFF Research Database (Denmark)

Taarning, Esben; Osmundsen, Christian Mårup; Yang, Xiaobo

2011-01-01

Heterogeneous catalysts have been a central element in the efficient conversion of fossil resources to fuels and chemicals, but their role in biomass utilization is more ambiguous. Zeolites constitute a promising class of heterogeneous catalysts and developments in recent years have demonstrated...... their potential to find broad use in the conversion of biomass. In this perspective we review and discuss the developments that have taken place in the field of biomass conversion using zeolites. Emphasis is put on the conversion of lignocellulosic material to fuels using conventional zeolites as well...

Anticorrosive Behavior and Porosity of Tricationic Phosphate and Zirconium Conversion Coating on Galvanized Steel

Science.gov (United States)

Velasquez, Camilo S.; Pimenta, Egnalda P. S.; Lins, Vanessa F. C.

2018-05-01

This work evaluates the corrosion resistance of galvanized steel treated with tricationic phosphate and zirconium conversion coating after painting, by using electrochemical techniques, accelerated and field corrosion tests. A non-uniform and heterogeneous distribution of zirconium on the steel surface was observed due to preferential nucleation of the zirconium on the aluminum-rich sites on the surface of galvanized steel. The long-term anti-corrosion performance in a saline solution was better for the phosphate coating up to 120 days. The coating capacitance registered a higher increase for the zirconium coatings than the phosphate coatings up to 120 days of immersion. This result agrees with the higher porosity of zirconium coating in relation to the phosphate coating. After 3840 h of accelerated corrosion test, and after 1 year of accelerated field test, zirconium-treated samples showed an average scribe delamination length higher than the phosphate-treated samples.

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 .

Electro-chemical deposition of nano hydroxyapatite-zinc coating on titanium metal substrate.

Science.gov (United States)

El-Wassefy, N A; Reicha, F M; Aref, N S

2017-08-13

Titanium is an inert metal that does not induce osteogenesis and has no antibacterial properties; it is proposed that hydroxyapatite coating can enhance its bioactivity, while zinc can contribute to antibacterial properties and improve osseointegration. A nano-sized hydroxyapatite-zinc coating was deposited on commercially pure titanium using an electro-chemical process, in order to increase its surface roughness and enhance adhesion properties. The hydroxyapatite-zinc coating was attained using an electro-chemical deposition in a solution composed of a naturally derived calcium carbonate, di-ammonium hydrogen phosphate, with a pure zinc metal as the anode and titanium as the cathode. The applied voltage was -2.5 for 2 h at a temperature of 85 °C. The resultant coating was characterized for its surface morphology and chemical composition using a scanning electron microscope (SEM), energy dispersive x-ray spectroscope (EDS), and Fourier transform infrared (FT-IR) spectrometer. The coated specimens were also evaluated for their surface roughness and adhesion quality. Hydroxyapatite-zinc coating had shown rosette-shaped, homogenous structure with nano-size distribution, as confirmed by SEM analysis. FT-IR and EDS proved that coatings are composed of hydroxyapatite (HA) and zinc. The surface roughness assessment revealed that the coating procedure had significantly increased average roughness (Ra) than the control, while the adhesive tape test demonstrated a high-quality adhesive coat with no laceration on tape removal. The developed in vitro electro-chemical method can be employed for the deposition of an even thickness of nano HA-Zn adhered coatings on titanium substrate and increases its surface roughness significantly.

Study on the deterioration process of a chromium-free conversion coating on AZ91D magnesium alloy in NaCl solution

International Nuclear Information System (INIS)

Zhao Ming; Wu Shusen; An Ping; Luo Jirong

2006-01-01

The morphology of a chromium-free conversion coating for AZ91D magnesium alloy was observed with an Atomic Force Microscopy. The results showed the uniform conversion coating has a relatively smooth appearance with shallow valleys. The EDX results indicated that the compositions of the coating were mainly compounds of Mg, Al, Mn, P, Ca and O. The XRD result showed that the coating contained amorphous materials and a small quantity of crystalline compound. The pitting product of the coating in NaCl water solution mainly composed of Mg, Cl, Mn, P, Ca and O. The corrosion behavior of the samples in NaCl solution was also studied by electrochemical impedance spectroscopy (EIS), which was characterized by one capacitive loop and one inductive loop. Based upon study on both a mathematical model for Faradic admittance of coating in NaCl solution and EIS, it could be considered that the inductive loop was caused by the adsorption of Cl anion and the appearance of pitting corrosion. A degradation mechanism of the coating in NaCl solution is set forth: dissolution velocity of the Cl - adsorption regions of the coating is higher than those non-adsorption regions, for Cl - anions are selective adsorption at some regions of coating surface. When the adsorption regions of coating layer are penetrated by dissolution, the pitting comes into being. The degradation mechanism of conversion coating and the mathematical model are consistent with the EIS results, polarization measurement results and coating's corrosion test results

A Molecularly Imprinted Polymer (MIP)-Coated Microbeam MEMS Sensor for Chemical Detection

Science.gov (United States)

2015-09-01

ARL-RP-0536 ● SEP 2015 US Army Research Laboratory A Molecularly Imprinted Polymer (MIP)- Coated Microbeam MEMS Sensor for...ARL-RP-0536 ● SEP 2015 US Army Research Laboratory A Molecularly Imprinted Polymer (MIP)- Coated Microbeam MEMS Sensor for Chemical...TITLE AND SUBTITLE A Molecularly Imprinted Polymer (MIP)-Coated Microbeam MEMS Sensor for Chemical Detection 5a. CONTRACT NUMBER 5b. GRANT NUMBER

Superhydrophobic coatings for aluminium surfaces synthesized by chemical etching process

Directory of Open Access Journals (Sweden)

Priya Varshney

2016-10-01

Full Text Available In this paper, the superhydrophobic coatings on aluminium surfaces were prepared by two-step (chemical etching followed by coating and one-step (chemical etching and coating in a single step processes using potassium hydroxide and lauric acid. Besides, surface immersion time in solutions was varied in both processes. Wettability and surface morphologies of treated aluminium surfaces were characterized using contact angle measurement technique and scanning electron microscopy, respectively. Microstructures are formed on the treated aluminium surfaces which lead to increase in contact angle of the surface (>150°. Also on increasing immersion time, contact angle further increases due to increase in size and depth of microstructures. Additionally, these superhydrophobic coatings show excellent self-cleaning and corrosion-resistant behavior. Water jet impact, floatation on water surface, and low temperature condensation tests assert the excellent water-repellent nature of coatings. Further, coatings are to be found mechanically, thermally, and ultraviolet stable. Along with, these coatings are found to be excellent regeneration ability as verified experimentally. Although aforesaid both processes generate durable and regenerable superhydrophobic aluminium surfaces with excellent self-cleaning, corrosion-resistant, and water-repellent characteristics, but one-step process is proved more efficient and less time consuming than two-step process and promises to produce superhydrophobic coatings for industrial applications.

Preparation and corrosion resistance of magnesium phytic acid/hydroxyapatite composite coatings on biodegradable AZ31 magnesium alloy.

Science.gov (United States)

Zhang, Min; Cai, Shu; Zhang, Feiyang; Xu, Guohua; Wang, Fengwu; Yu, Nian; Wu, Xiaodong

2017-06-01

In this work, a magnesium phytic acid/hydroxyapatite composite coating was successfully prepared on AZ31 magnesium alloy substrate by chemical conversion deposition technology with the aim of improving its corrosion resistance and bioactivity. The influence of hydroxyapatite (HA) content on the microstructure and corrosion resistance of the coatings was investigated. The results showed that with the increase of HA content in phytic acid solution, the cracks on the surface of the coatings gradually reduced, which subsequently improved the corrosion resistance of these coated magnesium alloy. Electrochemical measurements in simulated body fluid (SBF) revealed that the composite coating with 45 wt.% HA addition exhibited superior surface integrity and significantly improved corrosion resistance compared with the single phytic acid conversion coating. The results of the immersion test in SBF showed that the composite coating could provide more effective protection for magnesium alloy substrate than that of the single phytic acid coating and showed good bioactivity. Magnesium phytic acid/hydroxyapatite composite, with the desired bioactivity, can be synthesized through chemical conversion deposition technology as protective coatings for surface modification of the biodegradable magnesium alloy implants. The design idea of the new type of biomaterial is belong to the concept of "third generation biomaterial". Corrosion behavior and bioactivity of coated magnesium alloy are the key issues during implantation. In this study, preparation and corrosion behavior of magnesium phytic acid/hydroxyapatite composite coatings on magnesium alloy were studied. The basic findings and significance of this paper are as follows: 1. A novel environmentally friendly, homogenous and crack-free magnesium phytic acid/hydroxyapatite composite coating was fabricated on AZ31 magnesium alloy via chemical conversion deposition technology with the aim of enhancing its corrosion resistance and

Deactivating Chemical Agents Using Enzyme-Coated Nanofibers Formed by Electrospinning

Science.gov (United States)

2016-01-01

7.3mM/mg). Key words Coaxial electrospinning, DFPase, Enzyme, chemical warfare , nanofiber, decontamination . Introduction Chemical warfare ...Krile, R.; Nishioka, M.; Taylor, M.; Riggs, K.; Stone, H. Decontamination of Toxic Industrial Chemicals and Chemical Warfare Agents On Building...298 (Rev. 8-98) Prescribed by ANSI Std. Z39.18 MATS COATINGS ELECTROSPINNING CHEMICAL WARFARE

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}.

Chemical vapor deposition: A technique for applying protective coatings

Energy Technology Data Exchange (ETDEWEB)

Wallace, T.C. Sr.; Bowman, M.G.

1979-01-01

Chemical vapor deposition is discussed as a technique for applying coatings for materials protection in energy systems. The fundamentals of the process are emphasized in order to establish a basis for understanding the relative advantages and limitations of the technique. Several examples of the successful application of CVD coating are described. 31 refs., and 18 figs.

ASTM B 117 Screening of Nonchromate Conversion Coatings on Aluminum Alloys 2024, 2219, 5083, and 7075 Using DOD Paint Systems

National Research Council Canada - National Science Library

Placzankis, Brian

2003-01-01

This study examines the corrosion resistance of eight nonchromate conversion coatings versus hexavalent chromium-based Alodine 1200S controls on scribed coated test panels of aluminum alloys 2024, 2219, 5083, and 7075...

Dual stimuli responsive self-reporting material for chemical reservoir coating

Science.gov (United States)

Lee, Tae Hee; Song, Young Kyu; Park, Sun Hee; Park, Young Il; Noh, Seung Man; Kim, Jin Chul

2018-03-01

In this study, we introduce a novel dual stimuli responsive self-reporting thiol-epoxy thermoset (DSRTET) coatings which can detect both crack occurrence and pH variation. For crack detection, microcapsule containing tetraphenylethylene (TPE) which exhibits aggregation induced emission (AIE) effect was prepared via multi-step emulsion polymerization and dispersed in DSRTET coatings. For pH variation detection, commercial thymol blue as a pH indicator was added into the polymer matrix. The effect of microcapsule contents in DSRTET on their curing behavior, material properties, and crack sensitivity was characterized using an oscillatory rheology, rigid body pendulum test (RPT), nano-indentation test (NST), universal test machine (UTM) and scratch tester. It was revealed that crack sensitivity of DSRTET coatings was greatly influenced by material properties as well as microcapsule content. The color transition of DSRTET coatings in response to acid or base solution were quantitatively investigated using a multi-angle spectrophotometer after simple acid and base solution drop tests. The color of DSRTET coatings changed from a pale green to red for acidic solution and to blue for basic solution. Finally, The DSRTET used in this study was applied to laboratory scale chemical reservoirs in order to verify the potential as a dual stimuli response self-reporting coating which can detect both crack in coating material and chemical spill caused by the leakage or breakage of the reservoir part.

Preparation and chemical stability of iron-nitride-coated iron microparticles

International Nuclear Information System (INIS)

Luo Xin; Liu Shixiong

2007-01-01

Iron-nitride-coated iron microparticles were prepared by nitridation of the surface of iron microparticles with ammonia gas at a temperature of 510 deg. C. The phases, composition, morphology, magnetic properties, and chemical stability of the particles were studied. The phases were α-Fe, ε-Fe 3 N, and γ-Fe 4 N. The composition varied from the core to the surface, with 99.8 wt% Fe in the core, and 93.8 wt% Fe and 6 wt% N in the iron-nitride coating. The thickness of the iron-nitride coating was about 0.28 μm. The chemical stability of the microparticles was greatly improved, especially the corrosion resistance in corrosive aqueous media. The saturation magnetization and the coercive force were 17.1x10 3 and 68 kA/m, respectively. It can be concluded that iron-nitride-coated iron microparticles will be very useful in many fields, such as water-based magnetorheological fluids and polishing fluids

New Polymer Coatings for Chemically Selective Mass Sensors

Science.gov (United States)

Sims, S. C.; Wright, Cassandra; Cobb, J.; McCalla, T.; Revelle, R.; Morris, V. R.; Pollack, S. K.

1997-01-01

There is a current need to develop sensitive and chemically specific sensors for the detection of nitric acid for in-situ measurements in the atmosphere. Polymer coatings have been synthesized and tested for their sensitivity and selectivity to nitric acid. A primary requirement for these polymers is detectability down to the parts per trillion range. The results of studies using these polymers as coatings for quartz crystal microbalances (QCM) and surface acoustic wave (SAW) devices will be presented.

Mg substituted apatite coating from alkali conversion of acidic calcium phosphate

Energy Technology Data Exchange (ETDEWEB)

Navarro da Rocha, Daniel, E-mail: dnr.navarro@gmail.com [Military Institute of Engineering-IME, Pça. Gen. Tiburcio, 80, P. Vermelha, Urca, Rio de Janeiro, R.J. (Brazil); Cruz, Leila Rosa de Oliveira [Military Institute of Engineering-IME, Pça. Gen. Tiburcio, 80, P. Vermelha, Urca, Rio de Janeiro, R.J. (Brazil); Campos, José Brant de [Rio de Janeiro State University - UERJ, Rio de Janeiro, R.J. (Brazil); Marçal, Rubens L. Santana Blazutti [Military Institute of Engineering-IME, Pça. Gen. Tiburcio, 80, P. Vermelha, Urca, Rio de Janeiro, R.J. (Brazil); Mijares, Dindo Q.; Coelho, Paulo G. [Department of Biomaterials and Biomimetics, New York University College of Dentistry (NYU), New York, NY (United States); Prado da Silva, Marcelo H. [Military Institute of Engineering-IME, Pça. Gen. Tiburcio, 80, P. Vermelha, Urca, Rio de Janeiro, R.J. (Brazil)

2017-01-01

In this work, two solutions were developed: the first, rich in Ca{sup 2+}, PO{sub 4}{sup 3−} ions and the second, rich in Ca{sup 2+}, PO{sub 4}{sup 3−} and Mg{sup 2+}, defined as Mg-modified precursor solution. For each Mg-modified precursor solution, the concentrations of Mg{sup 2+} ions were progressively increased by 5%, 10% and 15%wt. The aims of this research were to investigate the influence of magnesium ions substitution in calcium phosphate coatings on titanium surface and to evaluate these coatings by bioactivity assay in McCoy culture medium. The obtained coatings were characterized by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) analysis, and the presence of Mg ions was confirmed by the inductively coupled plasma atomic emission spectroscopy (ICP) analysis. In vitro bioactivity assay in McCoy culture medium showed bioactivity after 14 days in incubation for the HA and 10% Mg-monetite coatings. The high chemical stability of Mg-HA coatings was verified by the bioactivity assays, and no bone-like apatite deposition, characteristic of bioactivity, was observed for Mg-HA coatings, for the time period used in this study. - Highlights: • The presence of Mg ions influenced the final apatite phase present in the produced coatings. • A lower efficiency in heterogeneous deposition and an exposure of Ti substrate in 5% Mg-monetite coatings was soon verified. • McCoy culture medium was effective in predicting the coatings bioactivity.

An electrothermal chemical technology for thermal spray coatings

International Nuclear Information System (INIS)

Wald, S.; Appelbaum, G.; Alimi, R.; Rabani, L.; Zoler, D.; Zhitomirsky, V.; Factor, M.; Roman, I.

1998-01-01

A new spray technology for producing hard-coatings, has been developed at the SOREQ Nuclear Research Center. The concept is based on the extensive experience accumulated at SOREQ in the course of the development of Electrothermal (ET), Electrothermal-Chemical (ETC) and Solid-Propellant Electrothermal-Chemical (SPETC) guns(r). High quality coatings may be obtained by thermal spraying powder particles onto a variety of substrates. Mature state-of-the-art technologies such as plasma spray, high velocity oxy fuel (HVOF) and detonation gun (D-Gun) are widely used for many applications. As each method has its own drawbacks there is a need for a combination of several parameters which cannot be achieved by any existing individual commercial technology. The method presented is oriented toward a high-quality, multi-step, high-throughput, easily programmable continuous coating process and relatively inexpensive technology. The combustion products of a solid or liquid propellant accelerate the powder particles of the coating material. A pulsed-plasma jet, provided by a confined capillary discharge, ignites the propellant and controls the combustion process. The powder particles are accelerated to velocities over 1000 m/s. Due to the very high carrier gas density, high velocity, high throughput and high powder consumption efficiency are obtained. The plasma jet enables control of the gas temperature and consequently influences the powder temperature

Characterization of ceramic sol-gel coatings as an alternative chemical conversion treatment on commercial carbon steel

International Nuclear Information System (INIS)

Dominguez-Crespo, M.A.; Garcia-Murillo, A.; Torres-Huerta, A.M.; Carrillo-Romo, F.J.; Onofre-Bustamante, E.; Yanez-Zamora, C.

2009-01-01

Sol-gel yttria-stabilized zirconia (YSZ) thin films were prepared on commercial carbon steel sheets by dip-coating technique followed by a low temperature heat treatment (473, 573, and 673 K for 1 h) in order to improve both corrosion properties and adhesion. For comparison, zirconia (ZrO 2 ) coatings have been also analyzed. Electrochemical techniques, Fourier Transform Infrared (FT-IR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to characterize the anticorrosion behavior of the coatings in a 3.5 wt% NaCl solution. The adhesion with a polyester organic coating was evaluated by the pull-off technique. The typical thickness of the deposited layers ranged from 1 to 1.3 μm depending on process parameters. The obtained results indicated that sol-gel ZrO 2 and YSZ coatings without an organic coating can act as protective barriers against wet corrosion during the first hours, but they fail when the time exposure is longer than 1 day. However, when synthesized films were used as a pre-treatment and an organic coating was added (top-coated), the anticorrosive and adhesion properties were strongly affected by the temperature of the treatment, and an increase in both properties was observed at higher temperatures. The structural and morphological characteristics of the coating provide an explanation of the role of each film in the electrochemical behavior in this aggressive medium. Comparing both systems, YSZ displayed greater protective and adhesion values than exhibited for ZrO 2 which can be correlated with the stabilization of the cubic phase

Oxygen Barrier Coating Deposited by Novel Plasma-enhanced Chemical Vapor Deposition

DEFF Research Database (Denmark)

Jiang, Juan; Benter, M.; Taboryski, Rafael Jozef

2010-01-01

We report the use of a novel plasma-enhanced chemical vapor deposition chamber with coaxial electrode geometry for the SiOx deposition. This novel plasma setup exploits the diffusion of electrons through the inner most electrode to the interior samples space as the major energy source. This confi......We report the use of a novel plasma-enhanced chemical vapor deposition chamber with coaxial electrode geometry for the SiOx deposition. This novel plasma setup exploits the diffusion of electrons through the inner most electrode to the interior samples space as the major energy source...... effect of single-layer coatings deposited under different reaction conditions was studied. The coating thickness and the carbon content in the coatings were found to be the critical parameters for the barrier property. The novel barrier coating was applied on different polymeric materials...

Simple down conversion nano-crystal coatings for enhancing Silicon-solar cells efficiency

Directory of Open Access Journals (Sweden)

Gur Mittelman

2016-09-01

Full Text Available Utilizing self-assembled nano-structured coatings on top of existing solar cells has thepotential to increase the total quantum efficiency of the cell using a simple and cheap process. In ourwork we have exploited the controlled absorption of nano-crystal with different band gaps to realizedown conversion artificial antennas that self-assembled on the device surface. The UV sun light isconverted to the visible light enhancing the solar cell performance in two complementary routes; a.protecting the solar cell and coatings from the UV illumination and therefore reducing the UVradiation damage. b. enhancing the total external quantum efficiency of the cell by one percent. Thisis achieved using a simple cheap process that can be adjusted to many different solar cells.

75 FR 4402 - Notice of National Conversation on Public Health and Chemical Exposures Leadership Council...

Science.gov (United States)

2010-01-27

... National Conversation on Public Health and Chemical Exposures Leadership Council Conference Call Time and... the second meeting of the National Conversation on Public Health and Chemical Exposures Leadership... Leadership Council provides overall guidance to the National Conversation project and will be responsible for...

Technology of combined chemical-mechanical fabrication of durable coatings

Science.gov (United States)

Smolentsev, V. P.; Ivanov, V. V.; Portnykh, A. I.

2018-03-01

The article presents the scientific fundamentals of methodology for calculating the modes and structuring the technological processes of combined chemical-mechanical fabrication of durable coatings. It is shown that they are based on classical patterns, describing the processes of simultaneous chemical and mechanical impact. The paper demonstrates the possibility of structuring a technological process, taking into account the systematic approach to impact management and strengthening the reciprocal positive influence of each impact upon the combined process. The combined processes have been planned for fabricating the model types of chemical-mechanical coatings of durable products in machine construction. The planning methodology is underpinned by a scientific hypothesis of a single source of impact management through energy potential of process components themselves, or by means of external energy supply through mechanical impact. The control of it is fairly thoroughly studied in the case of pulsed external strikes of hard pellets, similar to processes of vibroimpact hardening, thoroughly studied and mastered in many scientific schools of Russia.

Computational approaches to the chemical conversion of carbon dioxide

Energy Technology Data Exchange (ETDEWEB)

Cheng, Daojian; Negreiros, Fabio R.; Apra, Edoardo; Fortunelli, Alessandro

2013-06-01

The conversion of CO2 into fuels and chemicals is viewed as an attractive route for controlling the atmospheric concentration of this greenhouse gas and recycling it, but its industrial application is limited by the low selectivity and activity of the current catalysts. Theoretical modeling, in particular density-functional theory (DFT) simulations, provides a powerful and effective tool to discover chemical reaction mechanisms and design new catalysts for the chemical conversion of CO2, overcoming the repetitious and time/labor consuming trial-and-error experimental processes. In this article we give a comprehensive survey of recent advances on mechanism determination by DFT calculations for the catalytic hydrogenation of CO2 into CO, CH4, CH3OH, and HCOOH, and CO2 methanation, as well as the photo- and electrochemical reduction of CO2. DFT-guided design procedures of new catalytic systems are also reviewed, and challenges and perspectives in this field are outlined.

Steam initiated hydrotalcite conversion coatings

DEFF Research Database (Denmark)

Zhou, Lingli; Friis, Henrik; Roefzaad, Melanie

2018-01-01

A facile process of exploiting high-temperature steam to deposit nvironmentally friendly hydrotalcite (HT) coatings on Al alloy 6060 was developed in a spray system. Scanning electron microscopy showed the formationf a continuous and conformal coating comprised of a compact mass of crystallites. ...

Deposition of titanium coating on SiC fiber by chemical vapor deposition with Ti-I{sub 2} system

Energy Technology Data Exchange (ETDEWEB)

Luo, Xian, E-mail: luo_shenfan@hotmail.com; Wu, Shuai; Yang, Yan-qing; Jin, Na; Liu, Shuai; Huang, Bin

2017-06-01

Highlights: • The transformation paths of (Ti + I{sub 2}) powder to Ti coating is: Ti + I{sub 2} → (TiI{sub 2}, TiI{sub 3}) → Ti. • Uniform coating was obtained on SiC fiber, but it contained Si and C elements. • Deposition rate of the coating increased with the increase of temperature. • Deposition thickness increased with time and achieved the maximum at 90 min. - Abstract: Titanium coating was prepared on SiC fiber using titanium-iodine (Ti-I{sub 2}) mixture by hot-wall chemical vapor deposition. Thermodynamic analysis and experimental observation were carried out in this work. The thermodynamic analysis of the reactions in the Ti-I{sub 2} system indicates that Ti and I{sub 2} raw powder materials transform to titanium coating as follows: Ti + I{sub 2} → (TiI{sub 2}, TiI{sub 3}), and (TiI{sub 2}, TiI{sub 3}) → Ti. In theory, the conversions of TiI{sub 3} and TiI{sub 2} reach the maximum when Ti:I{sub 2} is 1:1.5, while in actual experiment that reached the maximum when Ti:I{sub 2} was 1:2, as there existed the waste of I{sub 2} due to sublimation. Typical deposited coating is relatively flat and uniform. However, as SiC is prone to react with Ti at high temperatures, the obtained coating contained some Si and C elements except for Ti. So the coating was not a pure Ti coating but contained some carbides and silicides. Deposition rate of the coating increased with the increase of temperature. The deposited thickness increased with the increase of heat preservation time, and achieved the maximum thickness at 90 min.

Chemical solution deposition: a path towards low cost coated conductors

International Nuclear Information System (INIS)

Obradors, X; Puig, T; Pomar, A; Sandiumenge, F; Pinol, S; Mestres, N; Castano, O; Coll, M; Cavallaro, A; Palau, A; Gazquez, J; Gonzalez, J C; Gutierrez, J; Roma, N; Ricart, S; Moreto, J M; Rossell, M D; Tendeloo, G van

2004-01-01

The achievement of low cost deposition techniques for high critical current YBa 2 Cu 3 O 7 coated conductors is one of the major objectives to achieve a widespread use of superconductivity in power applications. Chemical solution deposition techniques are appearing as a very promising methodology to achieve epitaxial oxide thin films at a low cost, so an intense effort is being carried out to develop routes for all chemical coated conductor tapes. In this work recent achievements will be presented towards the goal of combining the deposition of different type of buffer layers on metallic substrates based on metal-organic decomposition with the growth of YBa 2 Cu 3 O 7 layers using the trifluoroacetate route. The influence of processing parameters on the microstructure and superconducting properties will be stressed. High critical currents are demonstrated in 'all chemical' multilayers

The preparation and corrosion behaviors of MAO coating on AZ91D with rare earth conversion precursor film

Energy Technology Data Exchange (ETDEWEB)

Cai Jingshun [Department of Chemistry, Zhejiang University, Zheda Road 38, Hangzhou, Zhejiang 310027 (China); Cao Fahe, E-mail: nelson_cao@zju.edu.cn [Department of Chemistry, Zhejiang University, Zheda Road 38, Hangzhou, Zhejiang 310027 (China); Chang Linrong; Zheng Junjun [Department of Chemistry, Zhejiang University, Zheda Road 38, Hangzhou, Zhejiang 310027 (China); Zhang Jianqing; Cao Chunan [Department of Chemistry, Zhejiang University, Zheda Road 38, Hangzhou, Zhejiang 310027 (China); State Key Laboratory for Corrosion and Protection, Institute of Metal Research, The Chinese Academy of Sciences, Shenyang 110016 (China)

2011-02-01

A novel kind of micro-arc oxidation (MAO) coating was prepared on magnesium alloy surface coated with rare earth conversion film (RE-film) in an alkaline aluminum oxidation electrolyte by AC power source. Inspection of scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared (FTIR) microspectroscopy, the structure and composition of MAO coating formed on AZ91D with RE-film under different applied voltages were investigated and the performance of the optimized MAO coating compared with the MAO coating directly formed on magnesium alloy. As the pretreatment of magnesium alloy with RE-film, the cerium oxides can be incorporated into the MAO coatings, reduce porosity of the MAO coating surface and enhance the thickness of MAO coating. These structure features and the cerium oxides incorporated into the MAO coating result in greatly improved corrosion resistance. Base on electrochemistry impedance spectroscopy (EIS) measurement, the electronic structure and composition analysis of the MAO coating, a double-layer structure, with a compact inner layer and a porous outer layer, of the coating was proposed for understanding its corrosion process.

The preparation and corrosion behaviors of MAO coating on AZ91D with rare earth conversion precursor film

International Nuclear Information System (INIS)

Cai Jingshun; Cao Fahe; Chang Linrong; Zheng Junjun; Zhang Jianqing; Cao Chunan

2011-01-01

A novel kind of micro-arc oxidation (MAO) coating was prepared on magnesium alloy surface coated with rare earth conversion film (RE-film) in an alkaline aluminum oxidation electrolyte by AC power source. Inspection of scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared (FTIR) microspectroscopy, the structure and composition of MAO coating formed on AZ91D with RE-film under different applied voltages were investigated and the performance of the optimized MAO coating compared with the MAO coating directly formed on magnesium alloy. As the pretreatment of magnesium alloy with RE-film, the cerium oxides can be incorporated into the MAO coatings, reduce porosity of the MAO coating surface and enhance the thickness of MAO coating. These structure features and the cerium oxides incorporated into the MAO coating result in greatly improved corrosion resistance. Base on electrochemistry impedance spectroscopy (EIS) measurement, the electronic structure and composition analysis of the MAO coating, a double-layer structure, with a compact inner layer and a porous outer layer, of the coating was proposed for understanding its corrosion process.

A PMMA coated PMN–PT single crystal resonator for sensing chemical agents

International Nuclear Information System (INIS)

Frank, Michael; Kassegne, Sam; Moon, Kee S

2010-01-01

A highly sensitive lead magnesium niobate–lead titanate (PMN–PT) single crystal resonator coated with a thin film of polymethylmethacrylate (PMMA) useful for detecting chemical agents such as acetone, methanol, and isopropyl alcohol is presented. Swelling of the cured PMMA polymer layer in the presence of acetone, methanol, and isopropyl alcohol vapors is sensed as a mass change transduced to an electrical signal by the PMN–PT thickness shear mode sensor. Frequency change in the PMN–PT sensor is demonstrated to vary according to the concentration of the chemical vapor present within the sensing chamber. For acetone, the results indicate a frequency change more than 6000 times greater than that which would be expected from a quartz crystal microbalance coated with PMMA. This study is the first of its kind to demonstrate vapor loading of adsorbed chemical agents onto a polymer coated PMN–PT resonator

GM 9540P Cyclic Accelerated Corrosion Analysis of Nonchromate Conversion Coatings on Aluminum Alloys 2024, 2219, 5083, and 7075 Using DOD Paint Systems

National Research Council Canada - National Science Library

Placzankis, Brian

2003-01-01

This study examines corrosion resistance of eight nonchromate conversion coatings versus hexavalent chromium based Alodine 1200 controls on scribed coated test panels of aluminum alloys 2024, 2219, 5083, and 7075...

Comparative study on Ti/Zr/V and chromate conversion treated aluminum alloys: Anti-corrosion performance and epoxy coating adhesion properties

Energy Technology Data Exchange (ETDEWEB)

Zhu, Wen; Li, Wenfang, E-mail: mewfli@163.com; Mu, Songlin; Fu, Nianqing; Liao, Zhongmiao

2017-05-31

Highlights: • The surface roughness and surface free energy of the AA6063 are significantly increased after TZVCC treatment. • The anti-corrosion performance of the AA6063 is effectively enhanced after TZVCC treatment. • Both the corrosion resistance and wet adhesion properties of the epoxy coating on the AA6063 are noticeably improved after TZVCC treatment. - Abstract: In this study, a Ti/Zr/V conversion coating (TZVCC) was deposited on the surface of aluminum alloy 6063 (AA6063) as an alternative of the chromate conversion coating (CCC). Both the TZVCC treated AA6063 (TZVCC/AA6063) and CCC treated AA6063 (CCC/AA6063) were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), atomic force microscope (AFM) and contact angle measuring device. The anti-corrosion performance of the TZVCC/AA6063 and CCC/AA6063 was evaluated by electrochemical measurements and neutral salt spray tests. It showed that both the surface roughness and surface free energy of the AA6063 were significantly increased after TZVCC treatment. The anti-corrosion performance of TZVCC/AA6063 was superior to that of CCC/AA6063. In addition, the effects of the TZVCC and CCC on the adhesion properties and anti-corrosion performance of epoxy coating applied on samples were examined by pull-off tests and electrochemical impedance spectroscopy (EIS). The dry, wet and recovery adhesive strengths of the epoxy coating on TZVCC treated samples (epoxy coated TZVCC/AA6063) were very close to those of epoxy coating on CCC treated ones (epoxy coated CCC/AA6063). The epoxy coated TZVCC/AA6063 showed better corrosion resistance than the epoxy coated CCC/AA6063 and epoxy coated AA6063.

Appearance of a conductive carbonaceous coating in a CO2 dielectric barrier discharge and its influence on the electrical properties and the conversion efficiency

International Nuclear Information System (INIS)

Belov, Igor; Paulussen, Sabine; Bogaerts, Annemie

2016-01-01

This work examines the properties of a dielectric barrier discharge (DBD) reactor, built for CO 2 decomposition, by means of electrical characterization, optical emission spectroscopy and gas chromatography. The discharge, formed in an electronegative gas (such as CO 2 , but also O 2 ), exhibits clearly different electrical characteristics, depending on the surface conductivity of the reactor walls. An asymmetric current waveform is observed in the metal-dielectric (MD) configuration, with sparse high-current pulses in the positive half-cycle (HC) and a more uniform regime in the negative HC. This indicates that the discharge is operating in two alternating regimes with rather different properties. At high CO 2 conversion regimes, a conductive coating is deposited on the dielectric. This so-called coated MD configuration yields a symmetric current waveform, with current peaks in both the positive and negative HCs. In a double-dielectric (DD) configuration, the current waveform is also symmetric, but without current peaks in both the positive and negative HC. Finally, the DD configuration with conductive coating on the inner surface of the outer dielectric, i.e. so-called coated DD, yields again an asymmetric current waveform, with current peaks in the negative HC. These different electrical characteristics are related to the presence of the conductive coating on the dielectric wall of the reactor and can be explained by an increase of the local barrier capacitance available for charge transfer. The different discharge regimes affect the CO 2 conversion, more specifically, the CO 2 conversion is lowest in the clean DD configuration. It is somewhat higher in the coated DD configuration, and still higher in the MD configuration. The clean and coated MD configuration, however, gave similar CO 2 conversion. These results indicate that the conductivity of the dielectric reactor walls can highly promote the development of the high-amplitude discharge current pulses and

Roll-coating fabrication of flexible large area small molecule solar cells with power conversion efficiency exceeding 1%

DEFF Research Database (Denmark)

Liu, Wenqing; Liu, Shiyong; Zawacka, Natalia Klaudia

2014-01-01

All solution-processed flexible large area small molecule bulk heterojunction solar cells were fabricated via roll-coating technology. Our devices were produced from slot-die coating on a lab-scale mini roll-coater under ambient conditions without the use of spin-coating or vacuum evaporation.......01%, combined with an open circuit voltage of 0.73 V, a short-circuit current density of 3.13 mA cm (2) and a fill factor of 44% were obtained for the device with SM1, which was the first example reported for efficient roll-coating fabrication of flexible large area small molecule solar cells with PCE exceeding...... methods. Four diketopyrrolopyrrole based small molecules (SMs 1-4) were utilized as electron donors with (6,6)phenyl- C61-butyric acid methyl ester as an acceptor and their photovoltaic performances based on roll-coated devices were investigated. The best power conversion efficiency (PCE) of 1...

Chromate conversion coatings and their current application

Directory of Open Access Journals (Sweden)

P. Pokorny

2016-04-01

Full Text Available This paper describes formation, composition and possible production technologies of application chromate coatings. Summation of common examples of applications of these coatings in corrosion protection of metals and alloys is provided. Individual chromate coatings are divided by their dominant anions either with CrVI or CrIII. Restrictions of chromate coatings with dominantly CrVI and related toxicity of hexavalent chromium is discussed in detail. In conclusion, examples of both chromium and other, alternative coatings are summed up. Application of these coatings as a protection for concrete hot-dip galvanized reinforcement is also reviewed.

Self-healing Li-Al layered double hydroxide conversion coating modified with aspartic acid for 6N01 Al alloy

Science.gov (United States)

Zhang, Caixia; Luo, Xiaohu; Pan, Xinyu; Liao, Liying; Wu, Xiaosong; Liu, Yali

2017-02-01

A self-healing Li-Al layered double hydroxide conversion coating (LCC) modified with aspartic acid (ALCC) was prepared on 6N01 Al alloy for corrosion protection. Scanning electron microscopy (SEM) showed that a compact thin film has been successfully formed on the alloy. X-ray diffraction (XRD) and FT-IR spectra proved that species of aspartic acid anions were successfully intercalated into LCC. Potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and neutral salt spray (NSS) testing showed that the resultant ALCC could provide effective corrosion protection for the Al alloy. During immersion of the ALCC-coated alloy in 3.5% NaCl solution, new film was formed in the area of artificially introduced scratch, indicating its self-healing capability. XPS results demonstrated that Cl- anions exchange partial Asp anions according to the change content of element on conversion coating. From the above results, the possible mechanism via exchange/self-assembly was proposed to illustrate the phenomenon of self-healing.

Rare earth conversion coatings grown on AA6061 aluminum alloys. Corrosion studies

Energy Technology Data Exchange (ETDEWEB)

Brachetti S, S. B. [Instituto Tecnologico de Ciudad Madero, Av. 1o. de Mayo y Sor Juana I. de la Cruz, Col. Los Mangos, 89440 Ciudad Madero, Tanaulipas (Mexico); Dominguez C, M. A.; Torres H, A. M.; Onofre B, E. [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada - Altamira, Carretera Tampico-Puerto Industrial Altamira Km. 14.5, 89600 Altamira, Tamaulipas (Mexico); De la Cruz H, W., E-mail: mdominguezc@ipn.mx [UNAM, Centro de Nanociencias y Nanotecnologia, Apdo. Postal 2681, 22800 Ensenada, Baja California (Mexico)

2014-07-01

The present work is aimed to investigate the corrosion resistance of rare earth protective coatings deposited by spontaneous deposition on AA6061 aluminum alloy substrates. Coatings were deposited from water-based Ce(NO{sub 3}){sub 3} and La(NO{sub 3}){sub 3} solutions by varing parameters such as rare earth solution concentration, bath temperature and immersion time. The values of the Tafel slopes indicate that the cathodic process is favored by concentration polarization rather than activation polarization. Chemical and morphological characterizations of the surface before and after electrochemical evaluations were performed by X-ray photoelectron spectroscopy and scanning electron microscopy. (Author)

Rare earth conversion coatings grown on AA6061 aluminum alloys. Corrosion studies

International Nuclear Information System (INIS)

Brachetti S, S. B.; Dominguez C, M. A.; Torres H, A. M.; Onofre B, E.; De la Cruz H, W.

2014-01-01

The present work is aimed to investigate the corrosion resistance of rare earth protective coatings deposited by spontaneous deposition on AA6061 aluminum alloy substrates. Coatings were deposited from water-based Ce(NO 3 ) 3 and La(NO 3 ) 3 solutions by varing parameters such as rare earth solution concentration, bath temperature and immersion time. The values of the Tafel slopes indicate that the cathodic process is favored by concentration polarization rather than activation polarization. Chemical and morphological characterizations of the surface before and after electrochemical evaluations were performed by X-ray photoelectron spectroscopy and scanning electron microscopy. (Author)

Mechanical properties of chemical vapor deposited coatings for fusion reactor application

International Nuclear Information System (INIS)

Mullendore, A.W.; Whitley, J.B.; Pierson, H.O.; Mattox, D.M.

1980-01-01

Chemical vapor deposited coatings of TiB 2 , TiC and boron on graphite substrates are being developed for application as limiter materials in magnetic confinement fusion reactors. In this application severe thermal shock conditions exist and to do effective thermo-mechanical modelling of the material response it is necessary to acquire elastic moduli, fracture strength and strain to fracture data for the coatings. Four point flexure tests have been conducted from room temperature to 2000 0 C on TiB 2 and boron coated graphite with coatings in tension and compression and the mechanical properties extracted from the load-deflection data. In addition, stress relaxation tests from 500 to 1150 0 C were performed on TiB 2 and TiC coated graphite beams to assess the low levels of plastic deformation which occur in these coatings. Significant differences have been observed between the effective mechanical properties of the coatings and literature values of the bulk properties

GM 9540P Cyclic Accelerated Corrosion Analysis of Nonchromate Conversion Coatings on Aluminum Alloys 2024, 2219, 5083, and 7075 Using DoD Paint Systems

National Research Council Canada - National Science Library

Placzankis, Brian

2003-01-01

This study examines corrosion resistance of eight nonchromate conversion coatings versus bexavalent chromium based Alodine 1200 controls on scribed coated test panels of aluminum alloys 2024, 2219, 5083, and 7075...

The development of chemically vapor deposited mullite coatings for the corrosion protection of SiC

Energy Technology Data Exchange (ETDEWEB)

Auger, M.; Hou, P.; Sengupta, A.; Basu, S.; Sarin, V. [Boston Univ., MA (United States)

1998-05-01

Crystalline mullite coatings have been chemically vapor deposited onto SiC substrates to enhance the corrosion and oxidation resistance of the substrate. Current research has been divided into three distinct areas: (1) Development of the deposition processing conditions for increased control over coating`s growth rate, microstructure, and morphology; (2) Analysis of the coating`s crystal structure and stability; (3) The corrosion resistance of the CVD mullite coating on SiC.

Catalytic Conversion of Renewable Resources into Bulk and Fine Chemicals.

Science.gov (United States)

de Vries, Johannes G

2016-12-01

Several strategies can be chosen to convert renewable resources into chemicals. In this account, I exemplify the route that starts with so-called platform chemicals; these are relatively simple chemicals that can be produced in high yield, directly from renewable resources, either via fermentation or via chemical routes. They can be converted into the existing bulk chemicals in a very efficient manner using multistep catalytic conversions. Two examples are given of the conversion of sugars into nylon intermediates. 5-Hydroxymethylfurfural (HMF) can be prepared in good yield from fructose. Two hydrogenation steps convert HMF into 1,6-hexanediol. Oppenauer oxidation converts this product into caprolactone, which in the past, has been converted into caprolactam in a large-scale industrial process by reaction with ammonia. An even more interesting platform chemical is levulinic acid (LA), which can be obtained directly from lignocellulose in good yield by treatment with dilute sulfuric acid at 200°C. Hydrogenation converts LA into gamma-valerolactone, which is ring-opened and esterified in a gas-phase process to a mixture of isomeric methyl pentenoates in excellent selectivity. In a remarkable selective palladium-catalysed isomerising methoxycarbonylation, this mixture is converted in to dimethyl adipate, which is finally hydrolysed to adipic acid. Overall selectivities of both processes are extremely high. The conversion of lignin into chemicals is a much more complicated task in view of the complex nature of lignin. It was discovered that breakage of the most prevalent β-O-4 bond in lignin occurs not only via the well-documented C3 pathway, but also via a C2 pathway, leading to the formation of highly reactive phenylacetaldehydes. These compounds went largely unnoticed as they immediately recondense on lignin. We have now found that it is possible to prevent this by converting these aldehydes in a tandem reaction, as they are formed. For this purpose, we have used

Polyaniline-coated halloysite nanotubes via in-situ chemical polymerization

Energy Technology Data Exchange (ETDEWEB)

Zhang Long [State Key Laboratory of Applied Organic Chemistry and Institute of Polymer Science and Engineering, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000 (China); Wang Tingmei [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Liu Peng [State Key Laboratory of Applied Organic Chemistry and Institute of Polymer Science and Engineering, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000 (China)], E-mail: pliu@lzu.edu.cn

2008-12-30

Polyaniline coated halloysite nanotubes (PANI/HNTs) were prepared by the in-situ soapless emulsion polymerization of the anilinium chloride adsorbed halloysite nanotubes (HNTs), obtained by the dispersion of HNTs in acidic aqueous solution of aniline with magnetic stirring and ultrasonic irradiation, by using ammonium persulfate (APS) as oxidant. The effect of the acidities of the polymerizing media on the crystal structure of the nanotubes was investigated with X-ray diffraction (XRD) technique. The surface conducting coatings of the hybrids were characterized with X-ray photoelectron spectroscopy (XPS). The morphological analyses showed that the polyaniline coated halloysite nanotubes via the in-situ chemical oxidation polymerization with ultrasonic irradiation had the better well-defined structures, by the transmission electron microscopy (TEM). The conductivities of the PANI/HNTs hybrids increased with the increasing of the amounts of HCl dopant added in the emulsion polymerization.

Polyaniline-coated halloysite nanotubes via in-situ chemical polymerization

International Nuclear Information System (INIS)

Zhang Long; Wang Tingmei; Liu Peng

2008-01-01

Polyaniline coated halloysite nanotubes (PANI/HNTs) were prepared by the in-situ soapless emulsion polymerization of the anilinium chloride adsorbed halloysite nanotubes (HNTs), obtained by the dispersion of HNTs in acidic aqueous solution of aniline with magnetic stirring and ultrasonic irradiation, by using ammonium persulfate (APS) as oxidant. The effect of the acidities of the polymerizing media on the crystal structure of the nanotubes was investigated with X-ray diffraction (XRD) technique. The surface conducting coatings of the hybrids were characterized with X-ray photoelectron spectroscopy (XPS). The morphological analyses showed that the polyaniline coated halloysite nanotubes via the in-situ chemical oxidation polymerization with ultrasonic irradiation had the better well-defined structures, by the transmission electron microscopy (TEM). The conductivities of the PANI/HNTs hybrids increased with the increasing of the amounts of HCl dopant added in the emulsion polymerization.

Overall efficiencies for conversion of solar energy to a chemical fuel

Science.gov (United States)

Fish, J. D.

A complete and consistent scheme for determining the overall efficiency of a generalized process for the conversion of solar energy into a chemical fuel (e.g. hydrogen) is developed and applied to seven conversion processes: thermal, thermochemical, photovoltaic, photogalvanic, photoelectrolysis, photosynthesis and photochemical conversion. It is demonstrated that the overall efficiency of each of these processes is determined by ten common factors: maximum theoretical efficiency, inherent absorption losses, inherent internal losses, rate limiting effects, reflection losses, transmission losses, coverage losses, system construction requirements, parasitic losses and harvesting and conversion losses. Both state-of-the-art and optimistic values are assigned to each factor for each of the seven conversion processes. State-of-the-art overall efficiencies ranged from 5% for thermal conversion down to essentially zero for thermochemical. Optimistic values in the range of about 10 to 15% are calculated for several of the processes.

Corrosion resistance of Cr(III) conversion treatments applied on electrogalvanised steel and subjected to chloride containing media

International Nuclear Information System (INIS)

Tomachuk, C.R.; Elsner, C.I.; Di Sarli, A.R.; Ferraz, O.B.

2010-01-01

The corrosion resistance of pure zinc coatings can be improved through the application of suitable chemical passivation treatments. Hexavalent chromium compounds have widely been used to formulate conversion layers providing better anticorrosive protection as well as anchorage properties to painting systems. However, taking into account that they are produced using hazardous chemical compounds, the development of alternative and 'green' technologies with equivalent protective performance is a paramount purpose of many R and D laboratories working around the world. In the present paper, the corrosion behavior of zinc coatings obtained from free-cyanide alkaline baths and later subjected to a Cr 3+ based passivation treatment, with and without a sealing treatment, was studied. The experimental work involved electrochemical impedance spectroscopy measurements in 0.5 M NaCl solution, surface microstructural and morphological characterization by electronic microscopy as well as chemical analysis by EDXS. The salt spray test was also performed. The analysis and interpretation of all the data coming from this battery of tests allowed inferring that both the Cr 3+ based conversion treatment + adequate sealer presented a good corrosion resistance and, therefore, they could be used as neither a polluting nor toxic alternative to the traditional chromate coatings.

Chemical stability and osteogenic activity of plasma-sprayed boron-modified calcium silicate-based coatings.

Science.gov (United States)

Lu, Xiang; Li, Kai; Xie, Youtao; Huang, Liping; Zheng, Xuebin

2016-11-01

In recent years, CaSiO 3 bio-ceramic coatings have attracted great attention because of their good bioactivity. However, their high degradation rates in physiological environment restrict their practical applications. In this work, boron-modified CaSiO 3 ceramic (Ca 11 Si 4 B 2 O 22 , B-CS) coating was developed on Ti substrates by plasma-spraying technique attempting to obtain enhanced chemical stability and osteogenic activity. The B-CS coating possessed significantly increased chemical stability due to the introduction of boron and consequently the modified crystal structure, while maintaining good bioactivity. Scanning electron microscope and immunofluorescence studies showed that better cellular adhesion and extinctive filopodia-like processes were observed on the B-CS coating. Compared with the pure CaSiO 3 (CS) coating, the B-CS coating promoted MC3T3-E1 cells attachment and proliferation. In addition, enhanced collagen I (COL-I) secretion, alkaline phosphatase activity, and extracellular matrix mineralization levels were detected from the B-CS coating. According to RT-PCR results, notable up-regulation expressions of mineralized tissue-related genes, such as runt-related transcription factor 2 (Runx2), bone sialoprotein and osteocalcin, and bone morphogenetic protein 7 (BMP-7) were observed on the B-CS coating compared with the CS coating. The above results suggested that Ca 11 Si 4 B 2 O 22 coatings possess excellent osteogenic activity and might be a promising candidate for orthopedic applications.

Characterization of the corrosion protection mechanism of cerium-based conversion coatings on high strength aluminum alloys

Science.gov (United States)

Pinc, William Ross

The aim of the work presented in this dissertation is to investigate the corrosion protection mechanism of cerium-based conversion coatings (CeCCs) used in the corrosion protection of high strength aluminum alloys. The corrosion resistance of CeCCs involves two general mechanisms; barrier and active. The barrier protection mechanism was influenced by processing parameters, specifically surface preparation, post-treatment, and the use of gelatin. Post-treatment and the addition of gelatin to the coating solution resulted in fewer cracks and transformation of the coating to CePO4, which increased the corrosion resistance by improving the barrier aspect of CeCCs. CeCCs were found to best act as barriers when crack size was limited and CePO4 was present in the coating. CeCCs were found to protect areas of the substrate that were exposed in the coating, indicating that the coatings were more than simple barriers. CeCCs contained large cracks, underneath which subsurface crevices were connected to the surface by the cracks. Despite the observation that no cerium was present in crevices, coatings with crevices exhibited significant corrosion protection. The impedance of post-treated coatings with crevices increased during salt spray exposure. The increase in impedance was associated with the formation of protective oxides / hydroxides; however, crevice-free coatings also exhibited active protection leading to the conclusion that the formation of interfacial layers between the CeCC and the substrate also contributed to the active protection. Based on the overall results of the study, the optimal corrosion protection of CeCCs occurred when processing conditions produced coatings with morphologies and compositions that facilitated both the barrier and active protection mechanisms.

Silicon Nitride Antireflection Coatings for Photovoltaic Cells

Science.gov (United States)

Johnson, C.; Wydeven, T.; Donohoe, K.

1984-01-01

Chemical-vapor deposition adapted to yield graded index of refraction. Silicon nitride deposited in layers, refractive index of which decreases with distance away from cell/coating interface. Changing index of refraction allows adjustment of spectral transmittance for wavelengths which cell is most effective at converting light to electric current. Average conversion efficiency of solar cells increased from 8.84 percent to 12.63 percent.

Effect of biomass feedstock chemical and physical properties on energy conversion processes: Volume 1, Overview

Energy Technology Data Exchange (ETDEWEB)

Butner, R.S.; Elliott, D.C.; Sealock, L.J. Jr.; Pyne, J.W.

1988-12-01

Pacific Northwest Laboratory has completed an initial investigation of the effects of physical and chemical properties of biomass feedstocks relative to their performance in biomass energy conversion systems. Both biochemical conversion routes (anaerobic digestion and ethanol fermentation) and thermochemical routes (combustion, pyrolysis, and gasification) were included in the study. Related processes including chemical and physical pretreatment to improve digestibility, and size and density modification processes such as milling and pelletizing were also examined. This overview report provides background and discussion of feedstock and conversion relationships, along with recommendations for future research. The recommendations include (1) coordinate production and conversion research programs; (2) quantify the relationship between feedstock properties and conversion priorities; (3) develop a common framework for evaluating and characterizing biomass feedstocks; (4) include conversion effects as part of the criteria for selecting feedstock breeding programs; and (5) continue emphasis on multiple feedstock/conversion options for biomass energy systems. 9 refs., 3 figs., 2 tabs.

Chemically vapor deposited coatings for multibarrier containment of nuclear wastes

International Nuclear Information System (INIS)

Rusin, J.M.; Shade, J.W.; Kidd, R.W.; Browning, M.F.

1981-01-01

Chemical vapor deposition (CVD) was selected as a feasible method to coat ceramic cores, since the technology has previously been demonstrated for high-temperature gas-cooled reactor (HTGR) fuel particles. CVD coatings, including SiC, PyC (pyrolytic carbon), SiO 2 , and Al 2 O 3 were studied. This paper will discuss the development and characterization of PyC and Al 2 O 3 CVD coatings on supercalcine cores. Coatings were applied to 2 mm particles in either fluidized or vibrating beds. The PyC coating was deposited in a fluidized bed with ZrO 2 diluent from C 2 H 2 at temperatures between 1100 and 1200 0 C. The Al 2 O 3 coatings were deposited in a vibrated bed by a two-stage process to minimize loss of PyC during the overcoating operation. This process involved applying 10 μm of Al 2 O 3 using water vapor hydrolysis of AlCl 3 and then switching to the more surface-controlled hydrolysis via the H 2 + CO 2 reaction (3CO 2 + 3H 2 + 2AlCl 3 = Al 2 O 3 + 6HCl + 3CO). Typically, 50 to 80 μm Al 2 O 3 coatings were applied over 30 to 40 μm PyC coatings. The coatings were evaluated by metallographic examination, PyC oxidation tests, and leach resistance. After air oxidation for 100 hours at 750 0 C, the duplex PyC/Al 2 O 3 coated particles exhibited a weight loss of 0.01 percent. Leach resistance is being determined for temperatures from 50 to 150 0 C in various solutions. Typical results are given for selected ions. The leach resistance of supercalcine cores is significantly improved by the application of PyC and/or Al 2 O 3 coatings

Synthesis of mullite coatings by chemical vapor deposition

Energy Technology Data Exchange (ETDEWEB)

Mulpuri, R.P.; Auger, M.; Sarin, V.K. [Boston Univ., MA (United States)

1996-08-01

Formation of mullite on ceramic substrates via chemical vapor deposition was investigated. Mullite is a solid solution of Al{sub 2}O{sub 3} and SiO{sub 2} with a composition of 3Al{sub 2}O{sub 3}{circ}2SiO{sub 2}. Thermodynamic calculations performed on the AlCl{sub 3}-SiCl{sub 4}-CO{sub 2}-H{sub 2} system were used to construct equilibrium CVD phase diagrams. With the aid of these diagrams and consideration of kinetic rate limiting factors, initial process parameters were determined. Through process optimization, crystalline CVD mullite coatings have been successfully grown on SiC and Si{sub 3}N{sub 4} substrates. Results from the thermodynamic analysis, process optimization, and effect of various process parameters on deposition rate and coating morphology are discussed.

Conversion chimique des surfaces d'alliages d'aluminium sans chrome hexavalent

OpenAIRE

Ely , Marion

2016-01-01

Conversion coatings are used in aerospace industry to protect the metal from corrosion and to promote paint adhesion. Currently, chromate conversion coatings are used, but chromate is toxic and carcinogenic and its use will be forbidden by the European REACh regulation. TCP (Trivalent Chromium Protection) conversion coatings, are considered as a promising alternative to replace chromate conversion coating. This work focuses on the characterisation of the TCP layer and considers each step of t...

Thermo-Chemical Conversion of Microwave Activated Biomass Mixtures

Science.gov (United States)

Barmina, I.; Kolmickovs, A.; Valdmanis, R.; Vostrikovs, S.; Zake, M.

2018-05-01

Thermo-chemical conversion of microwave activated wheat straw mixtures with wood or peat pellets is studied experimentally with the aim to provide more effective application of wheat straw for heat energy production. Microwave pre-processing of straw pellets is used to provide a partial decomposition of the main constituents of straw and to activate the thermo-chemical conversion of wheat straw mixtures with wood or peat pellets. The experimental study includes complex measurements of the elemental composition of biomass pellets (wheat straw, wood, peat), DTG analysis of their thermal degradation, FTIR analysis of the composition of combustible volatiles entering the combustor, the flame temperature, the heat output of the device and composition of the products by comparing these characteristics for mixtures with unprocessed and mw pre-treated straw pellets. The results of experimental study confirm that mw pre-processing of straw activates the thermal decomposition of mixtures providing enhanced formation of combustible volatiles. This leads to improvement of the combustion conditions in the flame reaction zone, completing thus the combustion of volatiles, increasing the flame temperature, the heat output from the device, the produced heat energy per mass of burned mixture and decreasing at the same time the mass fraction of unburned volatiles in the products.

Assessment of Some Advanced Protective Schemes, Including Chromate and Non-Chromate Conversion Coatings for Mg Alloy ZE41A-T5 Using Electrochemical Impedance Spectroscopy

National Research Council Canada - National Science Library

Chang, Frank

1994-01-01

.... Electrochemical Impedance Spectroscopy (EIS) and salt spray tests have been employed to compare the corrosion behavior in chloride containing solutions of Mg alloy ZE41A-T5 which has been coated with various combinations of a conversion coating...

Chemical conversion of hemicellulose coproducts from forest biorefineries to polymers and chemicals

Energy Technology Data Exchange (ETDEWEB)

Boluk, Y.; Jost, R. [Alberta Research Council, Edmonton, AB (Canada)

2009-07-01

Raw material is the basis of the chemical industry. This presentation discussed the chemical conversion of hemicellulose coproducts from forest biorefineries to polymers and chemicals. Biorefining pretreatment processes open up the biomass structure, release hemicelluloses and overcome the resistance to enzymatic hydrolysis. Although hemicellulose is the second most abundant carbohydrate, it does not have many industrial applications. The state of released hemicellulose whether polymeric, oligomeric or monosaccharides depends primarily on the pretreatment process conditions. Physical pretreatment methods include high-pressure steaming and steam explosion; milling and grinding; extrusion; and high-energy radiation. The chemical pretreatment methods involve the use of alkali, acid, gas and oxidizing agents as well as solvents. The biological pretreatment methods involve the use of lignin consuming fungi and cellulose consuming fungi. A profitable use of C5 sugars in monomeric, oligomeric and polymeric forms is necessary for a viable wood to bioethanol process. Hemicellulose composition varies depending on the biomass source. It usually has a lower molecular weight than cellulose, contains branching, and is comprised of several different monosaccharides. The existing commercial chemical products include xylitol, mannitol, and furfural. The hemicellulose coproducts from a lignocellulosic biorefinery have the potential to become a feasible replacement for their fossil-based equivalents. tabs., figs.

Quantification of simultaneous solvent evaporation and chemical curing in thermoset coatings

DEFF Research Database (Denmark)

Kiil, Søren

2010-01-01

The mechanisms of simultaneous solvent evaporation and film formation in high-solids thermoset coatings are considered. The relevant phenomena, chemical reactions, solvent diffusion and evaporation, gelation, vitrification, network mobility restrictions, and crosslinking, are quantified and a mat...

Synthesis of Ceramic Protective Coatings for Chemical Plant Parts Operated in Hi-temperature and Corrosive/Erosive Environment

International Nuclear Information System (INIS)

Son, M. C.; Park, J. R.; Hong, K. T.; Seok, H. K.

2005-01-01

Some feasibility studies are conducted to produce an advanced ceramic coating, which reveals superior chemical and mechanical strength, on metal base structure used in chemical plant. This advanced coating on metallic frame can replace ceramic delivery pipe and reaction chamber used in chemical plant, which are operated in hi-temperature and corrosive/erosive environment. An dual spraying is adopted to reduce the residual stress in order to increase the coating thickness and the residual stress is estimated by in-situ manner. Then new methodology is tried to form special coating of yttrium aluminum garnet(YAG), which reveals hi-strength and low-creep rates at hi-temperature, superior anti-corrosion property, hi-stability against Alkali-Vapor corrosion, and so on, on iron base structure. To verify the formation of YAG during thermal spraying, XRD(X ray diffraction) technique was used

Sputtered titanium oxynitride coatings for endosseous applications: Physical and chemical evaluation and first bioactivity assays

Energy Technology Data Exchange (ETDEWEB)

Banakh, Oksana, E-mail: oksana.banakh@he-arc.ch [Institute of Applied Microtechnologies, Haute Ecole Arc Ingénierie (HES-SO), Eplatures-Grise 17, CH-2300 La Chaux-de-Fonds (Switzerland); Moussa, Mira, E-mail: mira.moussa@unige.ch [Laboratory of Biomaterials, University of Geneva, 19, rue Barthelemy Menn, CH-1205 Geneva (Switzerland); Matthey, Joel, E-mail: joel.matthey@he-arc.ch [Institute of Applied Microtechnologies, Haute Ecole Arc Ingénierie (HES-SO), Eplatures-Grise 17, CH-2300 La Chaux-de-Fonds (Switzerland); Pontearso, Alessandro, E-mail: alessandro.pontearso@he-arc.ch [Institute of Applied Microtechnologies, Haute Ecole Arc Ingénierie (HES-SO), Eplatures-Grise 17, CH-2300 La Chaux-de-Fonds (Switzerland); Cattani-Lorente, Maria, E-mail: maria.cattani-lorente@unige.ch [Laboratory of Biomaterials, University of Geneva, 19, rue Barthelemy Menn, CH-1205 Geneva (Switzerland); Sanjines, Rosendo, E-mail: rosendo.sanjines@epfl.ch [Ecole Polytechnique Fédérale de Lausanne (EPFL), Institute of Condensed Matter Physics, Station 3, CH-1015 Lausanne (Switzerland); Fontana, Pierre, E-mail: Pierre.Fontana@hcuge.ch [Haemostasis laboratory, Geneva University Hospital, Rue Gabrielle-Perret-Gentil 4, CH-1205 Geneva (Switzerland); Wiskott, Anselm, E-mail: anselm.wiskott@unige.ch [Laboratory of Biomaterials, University of Geneva, 19, rue Barthelemy Menn, CH-1205 Geneva (Switzerland); Durual, Stephane, E-mail: stephane.durual@unige.ch [Laboratory of Biomaterials, University of Geneva, 19, rue Barthelemy Menn, CH-1205 Geneva (Switzerland)

2014-10-30

Highlights: • Titanium oxynitride coatings (TiN{sub x}O{sub y}) with chemical composition ranging from TiN to TiO{sub 2} were deposited by magnetron sputtering from a metallic Ti target using a mixture of O{sub 2} + N{sub 2}. • The coatings structure as well as physical, chemical and mechanical properties progressively changes as a function of oxygen content in the TiN{sub x}O{sub y.} • All TiN{sub x}O{sub y} coatings show a significantly higher level of bioactivity as compared to bare Ti substrates (1.2 to 1.4 fold increase in cell proliferation). Despite variations in surface chemistry, topography and surface tension observed on films as a function of chemical composition, no significant differences in the films’ biological activity were observed after 3 days of testing. - Abstract: Titanium oxynitride coatings (TiN{sub x}O{sub y}) are considered a promising material for applications in dental implantology due to their high corrosion resistance, their biocompatibility and their superior hardness. Using the sputtering technique, TiN{sub x}O{sub y} films with variable chemical compositions can be deposited. These films may then be set to a desired value by varying the process parameters, that is, the oxygen and nitrogen gas flows. To improve the control of the sputtering process with two reactive gases and to achieve a variable and controllable coating composition, the plasma characteristics were monitored in-situ by optical emission spectroscopy. TiN{sub x}O{sub y} films were deposited onto commercially pure (ASTM 67) microroughened titanium plates by reactive magnetron sputtering. The nitrogen gas flow was kept constant while the oxygen gas flow was adjusted for each deposition run to obtain films with different oxygen and nitrogen contents. The physical and chemical properties of the deposited films were analyzed as a function of oxygen content in the titanium oxynitride. The potential application of the coatings in dental implantology was assessed by

Elaboration of colloidal silica sols in aqueous medium: functionalities, optical properties and chemical detection of coating

International Nuclear Information System (INIS)

Le Guevel, X.

2006-03-01

The aim of this work was to study surface reactivity of silica nanoparticles through physical and chemical properties of sols and coatings. Applications are numerous and they are illustrated in this work by optical coating preparation for laser components and chemical gas sensor development for nitroaromatics detection. On one hand, protocol synthesis of colloidal silica sols has been developed in water medium using sol-gel process (0 to 100 w%). These sols, so-called BLUESIL, are time-stable during at least one year. Homogeneous coatings having thickness fixed to 200 nm, have been prepared on silica substrate and show high porosity and high transparence. Original films have been developed using catalytic curing in gas atmosphere (ammonia curing) conferring good abrasive resistance to the coating without significant properties modification. In order to reduce film sensitivity to molecular adsorption (water, polluting agents... ), specific BLUESIL coatings have been prepared showing hydrophobic property due to apolar species grafting onto silica nanoparticles. Using this route, coatings having several functional properties such as transparence, hydrophobicity, high porosity and good abrasive resistance have been elaborated. On the other hand, we show that colloidal silica is a material specifically adapted to the detection of nitro aromatic vapors (NAC). Indeed, the use of colloidal silica as chemical gas sensor reveals very high sensitivity, selectivity to NAC compared to Volatile Organic Compound (V.O.C) and good detection performances during one year. Moreover, chemical sensors using functionalized colloidal silica have exhibited good results of detection, even in high humidity medium (≥70 %RH). (author)

Catalytic Conversion of Biomass to Fuels and Chemicals Using Ionic Liquids

Energy Technology Data Exchange (ETDEWEB)

Liu, Wei; Zheng, Richard; Brown, Heather; Li, Joanne; Holladay, John; Cooper, Alan; Rao, Tony

2012-04-13

This project provides critical innovations and fundamental understandings that enable development of an economically-viable process for catalytic conversion of biomass (sugar) to 5-hydroxymethylfurfural (HMF). A low-cost ionic liquid (Cyphos 106) is discovered for fast conversion of fructose into HMF under moderate reaction conditions without any catalyst. HMF yield from fructose is almost 100% on the carbon molar basis. Adsorbent materials and adsorption process are invented and demonstrated for separation of 99% pure HMF product and recovery of the ionic liquid from the reaction mixtures. The adsorbent material appears very stable in repeated adsorption/regeneration cycles. Novel membrane-coated adsorbent particles are made and demonstrated to achieve excellent adsorption separation performances at low pressure drops. This is very important for a practical adsorption process because ionic liquids are known of high viscosity. Nearly 100% conversion (or dissolution) of cellulose in the catalytic ionic liquid into small molecules was observed. It is promising to produce HMF, sugars and other fermentable species directly from cellulose feedstock. However, several gaps were identified and could not be resolved in this project. Reaction and separation tests at larger scales are needed to minimize impacts of incidental errors on the mass balance and to show 99.9% ionic liquid recovery. The cellulose reaction tests were troubled with poor reproducibility. Further studies on cellulose conversion in ionic liquids under better controlled conditions are necessary to delineate reaction products, dissolution kinetics, effects of mass and heat transfer in the reactor on conversion, and separation of final reaction mixtures.

Corrosion resistance of Cr(III) conversion treatments applied on electrogalvanised steel and subjected to chloride containing media

Energy Technology Data Exchange (ETDEWEB)

Tomachuk, C.R., E-mail: celia@br.surtec.com [Corrosion and Degradation Division, National Institute of Technology, Av. Venezuela, 82 sala 608, CEP 20081-312, Rio de Janeiro, RJ (Brazil); Elsner, C.I. [CIDEPINT: Research and Development Center in Paint Technology (CIC-CCT-CONICET-La Plata), Av. 52 s/n entre 121 y 122, CP B1900AYB, La Plata (Argentina); Di Sarli, A.R., E-mail: direccion@cidepint.gov.ar [CIDEPINT: Research and Development Center in Paint Technology (CIC-CCT-CONICET-La Plata), Av. 52 s/n entre 121 y 122, CP B1900AYB, La Plata (Argentina); Ferraz, O.B. [Corrosion and Degradation Division, National Institute of Technology, Av. Venezuela, 82 sala 608, CEP 20081-312, Rio de Janeiro, RJ (Brazil)

2010-01-15

The corrosion resistance of pure zinc coatings can be improved through the application of suitable chemical passivation treatments. Hexavalent chromium compounds have widely been used to formulate conversion layers providing better anticorrosive protection as well as anchorage properties to painting systems. However, taking into account that they are produced using hazardous chemical compounds, the development of alternative and 'green' technologies with equivalent protective performance is a paramount purpose of many R and D laboratories working around the world. In the present paper, the corrosion behavior of zinc coatings obtained from free-cyanide alkaline baths and later subjected to a Cr{sup 3+} based passivation treatment, with and without a sealing treatment, was studied. The experimental work involved electrochemical impedance spectroscopy measurements in 0.5 M NaCl solution, surface microstructural and morphological characterization by electronic microscopy as well as chemical analysis by EDXS. The salt spray test was also performed. The analysis and interpretation of all the data coming from this battery of tests allowed inferring that both the Cr{sup 3+} based conversion treatment + adequate sealer presented a good corrosion resistance and, therefore, they could be used as neither a polluting nor toxic alternative to the traditional chromate coatings.

Characterization of CuS nanocrystalline thin films synthesized by chemical bath deposition and dip coating techniques

International Nuclear Information System (INIS)

Chaki, Sunil H.; Deshpande, M.P.; Tailor, Jiten P.

2014-01-01

CuS thin films were synthesized by chemical bath deposition and dip coating techniques at ambient temperature. The energy dispersive analysis of X-rays of the thin films confirmed that both the as synthesized thin films are stoichiometric. The X-ray diffraction of the chemical bath deposited and dip coating deposited thin films showed that the films possess hexagonal structure having lattice parameters, a = b = 3.79 A and c = 16.34 A. The crystallite sizes determined from the X-ray diffraction data using Scherrer's formula for the chemical bath deposition and dip coating deposition thin films came out to be nearly 11 nm and 13 nm, respectively. The optical microscopy of the as deposited thin films surfaces showed that the substrates are well covered in both the deposited films. The scanning electron microscopy of the thin films clearly showed that in chemical bath deposited thin films the grain size varies from few μm to nm, while in dip coating deposited films the grain size ranges in nm. The optical bandgap determined from the optical absorbance spectrum analysis showed, chemical bath deposited thin films possess direct bandgap of 2.2 eV and indirect bandgap of 1.8 eV. In the case of dip coating deposited thin films, the direct bandgap is 2.5 eV and indirect bandgap is 1.9 eV. The d.c. electrical resistivity variation with temperature for both the deposited films showed that the resistivity decreases with temperature thus confirming the semiconducting nature. The thermoelectric power variations with temperature and the room temperature Hall Effect study of both the synthesized CuS thin films showed them to be of p-type conductivity. The obtained results are discussed in details. - Highlights: • CuS thin films were synthesized by chemical bath deposition and dip coating techniques. • The films possessed hexagonal structure. • The optical absorption showed that the films had direct and indirect bandgap. • Study of electrical transport properties

Plasma Assisted Chemical Vapour Deposition – Technological Design Of Functional Coatings

Directory of Open Access Journals (Sweden)

Januś M.

2015-06-01

Full Text Available Plasma Assisted Chemical Vapour Deposition (PA CVD method allows to deposit of homogeneous, well-adhesive coatings at lower temperature on different substrates. Plasmochemical treatment significantly impacts on physicochemical parameters of modified surfaces. In this study we present the overview of the possibilities of plasma processes for the deposition of diamond-like carbon coatings doped Si and/or N atoms on the Ti Grade2, aluminum-zinc alloy and polyetherketone substrate. Depending on the type of modified substrate had improved the corrosion properties including biocompatibility of titanium surface, increase of surface hardness with deposition of good adhesion and fine-grained coatings (in the case of Al-Zn alloy and improving of the wear resistance (in the case of PEEK substrate.

Surface characteristic of chemically converted graphene coated low carbon steel by electro spray coating method for polymer electrolyte membrane fuel cell bipolar plate.

Science.gov (United States)

Kim, Jungsoo; Kim, Yang Do; Nam, Dae Geun

2013-05-01

Graphene was coated on low carbon steel (SS400) by electro spray coating method to improve its properties of corrosion resistance and contact resistance. Exfoliated graphite was made of the graphite by chemical treatment (Chemically Converted Graphene, CCG). CCG is distributed using dispersing agent, and low carbon steel was coated with diffuse graphene solution by electro spray coating method. The structure of the CCG was analyzed using XRD and the coating layer of surface was analyzed using SEM. Analysis showed that multi-layered graphite structure was destroyed and it was transformed in to fine layers graphene structure. And the result of SEM analysis on the surface and the cross section, graphene layer was uniformly formed with 3-5 microm thickness on the surface of substrate. Corrosion resistance test was applied in the corrosive solution which is similar to the polymer electrolyte membrane fuel cell (PEMFC) stack inside. And interfacial contact resistance (ICR) test was measured to simulate the internal operating conditions of PEMFC stack. As a result of measuring corrosion resistance and contact resistance, it could be confirmed that low carbon steel coated with CCG was revealed to be more effective in terms of its applicability as PEMFC bipolar plate.

The chemical stability of TRISO-coated HTGR fuel. Pt. 1. Status report

International Nuclear Information System (INIS)

Groot, P.; Cordfunke, E.H.P.; Konings, R.J.M.

1994-12-01

The US fuel seemed to be more difficult to produce than the German fuel. Also the chemical stability of this fuel must be investigated. The conditions are more severe in the US concept than in the German concept. Oxidation of the graphite seems to be no problem, according to US HTGR concept. A ZrC coating seems to have a number of advantages with regard to the SiC coating: (1) Better retention, (2) no reaction with Pd, (3) no thermal dissociation. Only the oxidation resistance is worse than SiC. Also the maximum stress must be determined that the ZrC coating can have. (orig./HP)

DMF as an Additive in a Two-Step Spin-Coating Method for 20% Conversion Efficiency in Perovskite Solar Cells.

Science.gov (United States)

Wu, Jionghua; Xu, Xin; Zhao, Yanhong; Shi, Jiangjian; Xu, Yuzhuan; Luo, Yanhong; Li, Dongmei; Wu, Huijue; Meng, Qingbo

2017-08-16

DMF as an additive has been employed in FAI/MAI/IPA (FA= CH 2 (NH 2 ) 2 , MA = CH 3 NH 3 , IPA = isopropanol) solution for a two-step multicycle spin-coating method in order to prepare high-quality FA x MA 1-x PbI 2.55 Br 0.45 perovskite films. Further investigation reveals that the existence of DMF in the FAI/MAI/IPA solution can facilitate perovskite conversion, improve the film morphology, and reduce crystal defects, thus enhancing charge-transfer efficiency. By optimization of the DMF amount and spin-coating cycles, compact, pinhole-free perovskite films are obtained. The nucleation mechanisms of perovskite films in our multicycle spin-coating process are suggested; that is, the introduction of DMF in the spin-coating FAI/MAI/IPA solution can lead to the formation of an amorphous phase PbX 2 -AI-DMSO-DMF (X = I, Br; A = FA, MA) instead of intermediate phase (MA) 2 Pb 3 I 8 ·2DMSO. This amorphous phase, similar to that in the one-step method, can help FAI/MAI penetrate into the PbI 2 framework to completely convert into the perovskite. As high as 20.1% power conversion efficiency (PCE) has been achieved with a steady-state PCE of 19.1%. Our work offers a simple repeatable method to prepare high-quality perovskite films for high-performance PSCs and also help further understand the perovskite-crystallization process.

Carbon dioxide management by chemical conversion to methanol: HYDROGENATION and BI-REFORMING

International Nuclear Information System (INIS)

Wiesberg, Igor L.; Medeiros, José Luiz de; Alves, Rita M.B.; Coutinho, Paulo L.A.; Araújo, Ofélia Q.F.

2016-01-01

Highlights: • Evaluation of carbon dioxide conversion to methanol by two chemical routes. • HYDROGENATION: conversion via catalytic hydrogenation at high pressure. • BI-REFORMING: conversion via syngas from bi-reforming of natural gas. • HYDROGENATION is viable for hydrogen price inferior to 1000 US$/t. • BI-REFORMING is unable to avoid emissions; viable only if gas price is very low. - Abstract: Chemical conversion of carbon dioxide to methanol has the potential to address two relevant sustainability issues: economically feasible replacement of fossil raw materials and avoidance of greenhouse gas emissions. However, chemical stability of carbon dioxide is a challenging impediment to conversion requiring severe reaction conditions at the expense of increased energy input, therefore adding capital, operation and environmental costs, which could result in partial or total override of its potential sustainability as feedstock to the chemical and energy industries. This work investigates two innovative chemical destinations of carbon dioxide to methanol, namely a direct conversion through carbon dioxide hydrogenation (HYDROGENATION), and an indirect via carbon dioxide conversion to syngas through bi-reforming (BI-REFORMING). Process simulation is used to obtain mass and energy balances needed to support assessment of economic and environmental performance. A business scenario is considered where an industrial source of nearly pure carbon dioxide exists and an investment decision for utilization of carbon dioxide is faced. Due to uncertainties in prices of the raw materials, hydrogen (HYDROGENATION) and natural gas (BI-REFORMING), the decision procedure includes the definition of price thresholds to reach profitability. Sensitivity analyses are performed varying costs with greater uncertainty, i.e., carbon dioxide and methanol, and recalculating maximum allowable prices of raw materials. The analyses show that in a Brazilian scenario, BI-REFORMING is unlikely

Crack-resistant polyimide coating for high-capacity battery anodes

Science.gov (United States)

Li, Yingshun; Wang, Shuo; Lee, Pui-Kit; He, Jieqing; Yu, Denis Y. W.

2017-10-01

Electrode cracking is a serious problem that hinders the application of many next-generation high-capacity anode materials for lithium-ion batteries. Even though nano-sizing the material can reduce fracturing of individual particles, capacity fading is still observed due to large volume change and loss of contact in the electrode during lithium insertion and extraction. In this study, we design a crack-resistant high-modulus polyimide coating with high compressive strength which can hold multiple particles together during charge and discharge to maintain contact. The effectiveness of the coating is demonstrated on tin dioxide, a high-capacity large-volume-change material that undergoes both alloy and conversion reactions. The polyimide coating improves capacity retention of SnO2 from 80% to 100% after 80 cycles at 250 mA g-1. Stable capacity of 585 mAh g-1 can be obtained even at 500 mA g-1 after 300 cycles. Scanning electron microscopy and in-situ dilatometry confirm that electrode cracking is suppressed and thickness change is reduced with the coating. In addition, the chemically-stable polyimide film can separate the surface from direct contact with electrolyte, improving coulombic efficiency to ∼100%. We expect the novel strategy of suppressing electrode degradation with a crack-resistant coating can also be used for other alloy and conversion-based anodes.

Surface Modification of α-Fe Metal Particles by Chemical Surface Coating

Institute of Scientific and Technical Information of China (English)

无

2003-01-01

The structure of α-Fe metal magnetic recording particles coated with silane coupling agents have been studied by TEM, FT-IR, EXAFS, Mossbauer. The results show that a close, uniform, firm and ultra thin layer, which is beneficial to the magnetic and chemical stability, has been formed by the cross-linked chemical bond Si-O-Si. And the organic molecule has chemically bonded to the particle surface, which has greatly affected the surface Fe atom electronic structure. Furthermore, the covalent bond between metal particle surface and organic molecule has obvious effect on the near edge structure of the surface Fe atoms.

Effects of acid and alkaline based surface preparations on spray deposited cerium based conversion coatings on Al 2024-T3

Energy Technology Data Exchange (ETDEWEB)

Pinc, W. [Department of Materials Science Engineering, Materials Research Center, Missouri University of Science and Technology, Rolla, MO 65409 (United States)], E-mail: wrphw5@mst.edu; Geng, S.; O' Keefe, M.; Fahrenholtz, W.; O' Keefe, T. [Department of Materials Science Engineering, Materials Research Center, Missouri University of Science and Technology, Rolla, MO 65409 (United States)

2009-01-15

Cerium based conversion coatings were spray deposited on Al 2024-T3 and characterized to determine the effect of surface preparation on the deposition rate and surface morphology. It was found that activation of the panel using a 1-wt.% sulfuric acid solution increased the coating deposition rate compared to alkaline cleaning alone. Analysis of the surface morphology of the coatings showed that the coatings deposited on the acid treated panels exhibited fewer visible cracks compared to coatings on alkaline cleaned panels. Auger electron spectroscopy depth profiling showed that the acid activation decreased the thickness of the aluminum oxide layer and the concentration of magnesium on the surface of the panels compared to the alkaline treatment. Additionally, acid activation increased the copper concentration at the surface of the aluminum substrate. Based on the results, the acid based surface treatment appeared to expose copper rich intermetallics, thus increasing the number of cathodic sites on the surface, which led to an overall increase in the deposition rate.

Thermal conversion of biomass to valuable fuels, chemical feedstocks and chemicals

Science.gov (United States)

Peters, William A [Lexington, MA; Howard, Jack B [Winchester, MA; Modestino, Anthony J [Hanson, MA; Vogel, Fredreric [Villigen PSI, CH; Steffin, Carsten R [Herne, DE

2009-02-24

A continuous process for the conversion of biomass to form a chemical feedstock is described. The biomass and an exogenous metal oxide, preferably calcium oxide, or metal oxide precursor are continuously fed into a reaction chamber that is operated at a temperature of at least 1400.degree. C. to form reaction products including metal carbide. The metal oxide or metal oxide precursor is capable of forming a hydrolizable metal carbide. The reaction products are quenched to a temperature of 800.degree. C. or less. The resulting metal carbide is separated from the reaction products or, alternatively, when quenched with water, hydolyzed to provide a recoverable hydrocarbon gas feedstock.

Coating of carbon short fibers with thin ceramic layers by chemical vapor deposition

International Nuclear Information System (INIS)

Hackl, Gerrit; Gerhard, Helmut; Popovska, Nadejda

2006-01-01

Carbon short fiber bundles with a length of 6 mm were uniformly coated using specially designed, continuous chemical vapor deposition (CVD) equipment. Thin layers of titanium nitride, silicon nitride (SiC) and pyrolytic carbon (pyC) were deposited onto several kilograms of short fibers in this large scale CVD reactor. Thermo-gravimetric analyses and scanning electron microscopy investigations revealed layer thicknesses between 20 and 100 nm on the fibers. Raman spectra of pyC coated fibers show a change of structural order depending on the CVD process parameters. For the fibers coated with SiC, Raman investigations showed a deposition of amorphous SiC. The coated carbon short fibers will be applied as reinforcing material in composites with ceramic and metallic matrices

Chemical Conversion of Human Fibroblasts into Functional Schwann Cells

Directory of Open Access Journals (Sweden)

Eva C. Thoma

2014-10-01

Full Text Available Direct transdifferentiation of somatic cells is a promising approach to obtain patient-specific cells for numerous applications. However, conversion across germ-layer borders often requires ectopic gene expression with unpredictable side effects. Here, we present a gene-free approach that allows efficient conversion of human fibroblasts via a transient progenitor stage into Schwann cells, the major glial cell type of peripheral nerves. Using a multikinase inhibitor, we transdifferentiated fibroblasts into transient neural precursors that were subsequently further differentiated into Schwann cells. The resulting induced Schwann cells (iSCs expressed numerous Schwann cell-specific proteins and displayed neurosupportive and myelination capacity in vitro. Thus, we established a strategy to obtain mature Schwann cells from human postnatal fibroblasts under chemically defined conditions without the introduction of ectopic genes.

Effect of Thickness on the Morphology and Corrosion Behavior of Cerium-Based Conversion Coatings on AZ31B Magnesium Alloy

Science.gov (United States)

Castano, Carlos E.; Maddela, Surender; O'Keefe, Matthew J.; Wang, Yar-Ming

Cerium-based conversion coatings (CeCCs) were deposited onto AZ31B magnesium alloy substrates using a spontaneous reaction of CeCl3, H2O2 and gelatin in a water-based solution. The coating thickness was adjusted by controlling the immersion time in the deposition solution. Prior to deposition, the AZ31B substrates were treated using an acid pickling in nitric acid and then an alkaline cleaning in sodium metasilicate pentahydrate. After deposition, the coated samples were immersed in a phosphate bath that converted cerium oxide/hydroxide into cerium phosphate. Electrochemical impedance spectroscopy, potentiodynamic polarization and neutral salt spray testing studies indicated that 100 nm thick CeCC had better corrosion performance than 400 nm coatings. Characterization of the CeCCs by transmission electron microscopy (TEM) revealed a three layer structure with different compositions.

Thermal barrier coatings on gas turbine blades: Chemical vapor deposition (Review)

Science.gov (United States)

Igumenov, I. K.; Aksenov, A. N.

2017-12-01

Schemes are presented for experimental setups (reactors) developed at leading scientific centers connected with the development of technologies for the deposition of coatings using the CVD method: at the Technical University of Braunschweig (Germany), the French Aerospace Research Center, the Materials Research Institute (Tohoku University, Japan) and the National Laboratory Oak Ridge (USA). Conditions and modes for obtaining the coatings with high operational parameters are considered. It is established that the formed thermal barrier coatings do not fundamentally differ in their properties (columnar microstructure, thermocyclic resistance, thermal conductivity coefficient) from standard electron-beam condensates, but the highest growth rates and the perfection of the crystal structure are achieved in the case of plasma-chemical processes and in reactors with additional laser or induction heating of a workpiece. It is shown that CVD reactors can serve as a basis for the development of rational and more advanced technologies for coating gas turbine blades that are not inferior to standard electron-beam plants in terms of the quality of produced coatings and have a much simpler and cheaper structure. The possibility of developing a new technology based on CVD processes for the formation of thermal barrier coatings with high operational parameters is discussed, including a set of requirements for industrial reactors, high-performance sources of vapor precursors, and promising new materials.

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.)

Layer-by-layer fabrication of chemical-bonded graphene coating for solid-phase microextraction.

Science.gov (United States)

Zhang, Suling; Du, Zhuo; Li, Gongke

2011-10-01

A new fabrication strategy of the graphene-coated solid-phase microextraction (SPME) fiber is developed. Graphite oxide was first used as starting coating material that covalently bonded to the fused-silica substrate using 3-aminopropyltriethoxysilane (APTES) as cross-linking agent and subsequently deoxidized by hydrazine to give the graphene coating in situ. The chemical bonding between graphene and the silica fiber improve its chemical stability, and the obtained fiber was stable enough for more than 150 replicate extraction cycles. The graphene coating was wrinkled and folded, like the morphology of the rough tree bark. Its performance is tested by headspace (HS) SPME of polycyclic aromatic hydrocarbons (PAHs) followed by GC/MS analysis. The results showed that the graphene-coated fiber exhibited higher enrichment factors (EFs) from 2-fold for naphthalene to 17-fold for B(b)FL as compared to the commercial polydimethylsioxane (PDMS) fiber, and the EFs increased with the number of condensed rings of PAHs. The strong adsorption affinity was believed to be mostly due to the dominant role of π-π stacking interaction and hydrophobic effect, according to the results of selectivity study for a variety of organic compounds including PAHs, the aromatic compounds with different substituent groups, and some aliphatic hydrocarbons. For PAHs analysis, the graphene-coated fiber showed good precision (<11%), low detection limits (1.52-2.72 ng/L), and wide linearity (5-500 ng/L) under the optimized conditions. The repeatability of fiber-to-fiber was 4.0-10.8%. The method was applied to simultaneous analysis of eight PAHs with satisfactory recoveries, which were 84-102% for water samples and 72-95% for soil samples, respectively.

Molybdate Coatings for Protecting Aluminum Against Corrosion

Science.gov (United States)

Calle, Luz Marina; MacDowell, Louis G.

2005-01-01

Conversion coatings that comprise mixtures of molybdates and several additives have been subjected to a variety of tests to evaluate their effectiveness in protecting aluminum and alloys of aluminum against corrosion. Molybdate conversion coatings are under consideration as replacements for chromate conversion coatings, which have been used for more than 70 years. The chromate coatings are highly effective in protecting aluminum and its alloys against corrosion but are also toxic and carcinogenic. Hexavalent molybdenum and, hence, molybdates containing hexavalent molybdenum, have received attention recently as replacements for chromates because molybdates mimic chromates in a variety of applications but exhibit significantly lower toxicity. The tests were performed on six proprietary formulations of molybdate conversion coatings, denoted formulations A through F, on panels of aluminum alloy 2024-T3. A bare alloy panel was also included in the tests. The tests included electrochemical impedance spectroscopy (EIS), measurements of corrosion potentials, scanning electron microscopy (SEM) with energy-dispersive spectroscopy (EDS), and x-ray photoelectron spectroscopy (XPS).

75 FR 52355 - Draft National Conversation on Public Health and Chemical Exposures Work Group Reports...

Science.gov (United States)

2010-08-25

... DEPARTMENT OF HEALTH AND HUMAN SERVICES Centers for Disease Control and Prevention Draft National Conversation on Public Health and Chemical Exposures Work Group Reports; Opportunity for Public Comment AGENCY.../nationalconversation/work_groups.html . For additional information on the National Conversation on Public Health and...

Chemical treatment and biomimetic coating evaluating in zirconia-alumina ceramics

International Nuclear Information System (INIS)

Aguiar, Amanda Abati

2007-01-01

Ceramic materials, as alumina and zirconia have been explored along the years as biomaterials application. The bio inert nature has been stimulating the development of new alternatives, as chemical treatments to improve the biological application of these ceramics. The biomimetic process of bio inert ceramics for coating apatite is based on soaking the implant in a simulated body fluid, SBF, with ion concentrations nearly equal to those of human blood plasma. The bioactivity of the material is related with the formation of a layer constituted of hydroxyapatite low crystalline, similar to the biological apatite. The biocompatibility associated to the structural properties of the alumina and zirconia has been stimulating the clinical use of these materials, mainly in areas of larger mechanical requests, places not recommended for bioactive hydroxyapatite, for instance. In this work samples of alumina, zirconia doped with Yttria (3% mol) and composites of alumina and zirconia doped with Yttria (3% mol) were prepared by co-precipitation method, calcinate, sintered, chemically treated with solutions of acid phosphoric and sodium hydroxide and them immersed in 1.0 M and 1.5 M SBF. The calcinate powders were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), gas adsorption (BET) and laser diffraction. The XRD results indicate that the samples are low crystalline. It was observed for BET that the samples present high specific surface area. The results of laser diffraction and SEM showed that the powders are agglomerates. The sintered samples were analyzed by XRD, SEM and X-ray fluorescence (XRF). The phases quantified by Rietveld method were: cubic, tetragonal and monoclinic of the zirconia, besides the phase alpha of the alumina. The chemical treatment with phosphoric acid didn't present a tendency of larger apatite formation in relation to the samples no chemically treated. The treatment with sodium hydroxide provoked accentuated transformation of

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.)

Catalytic Conversion of Carbohydrates to Initial Platform Chemicals: Chemistry and Sustainability.

Science.gov (United States)

Mika, László T; Cséfalvay, Edit; Németh, Áron

2018-01-24

The replacement of fossil resources that currently provide more than 90% of our energy needs and feedstocks of the chemical industry in combination with reduced emission of carbon dioxide is one of the most pressing challenges of mankind. Biomass as a globally available resource has been proposed as an alternative feedstock for production of basic building blocks, which could partially or even fully replace the currently utilized fossil-based ones in well-established chemical processes. The destruction of lignocellulosic feed followed by oxygen removal from its cellulose and hemicellulose content by catalytic processes results in the formation of initial platform chemicals (IPCs). However, their sustainable production strongly depends on the availability of resources, their efficient or even industrially viable conversion processes, and replenishment time of feedstocks. Herein, we overview recent advances and developments in catalytic transformations of the carbohydrate content of lignocellulosic biomass to IPCs (i.e., ethanol, 3-hydroxypropionic acid, isoprene, succinic and levulinic acids, furfural, and 5-hydroxymethylfurfural). The mechanistic aspects, development of new catalysts, different efficiency indicators (yield and selectivity), and conversion conditions of their production are presented and compared. The potential biochemical production routes utilizing recently engineered microorganisms are reviewed, as well. The sustainability metrics that could be applied to the chemical industry (individual set of sustainability indicators, composite indices methods, material and energy flow analysis-based metrics, and ethanol equivalents) are also overviewed as well as an outlook is provided to highlight challenges and opportunities associated with this huge research area.

In-situ phosphatizing coatings for aerospace, OEM and coil coating applications

Science.gov (United States)

Neuder, Heather Aurelia

The current metal coating process is a multi-step process. The surface is cleaned, primered, dried and then painted. The process is labor intensive and time consuming. The wash primer is a conversion coating, which prepares metal surface for better paint adhesion. The wash primers currently used often contain hexavalent chromium (Cr6+), which seals the pores in the conversion coating. The presence of hexavalent chromium, a known carcinogen, and volatile organic compounds (VOCs) make waste disposal expensive and pose dangers to workers. The novel technique of in-situ phosphatizing coating (ISPC) is a single-step, chrome-free alternative to the present coating practice. Formulation of an ISPC involves predispersal of an in-situ phosphatizing reagent (ISPR) into the paint system to form a stable formulation. The ISPR reacts with the metal surface and bonds with the paint film simultaneously, which eliminates the need for a conversion coating. In acid catalyzed paint systems, such as polyester-melamine paints, the ISPR also catalyzes cross-linking reactions between the melamine and the polyester polyols. ISPCs are formulated using commercially available coating systems including: polyester-melamine, two-component epoxy, polyurethane and high-hydroxy content polyester-melamine coil coating. The ISPCs are applied to metal substrates and their performances are evaluated using electrochemical, thermal and standard American Society for Testing and Materials (ASTM) testing methods. In addition, ISPCs were designed and formulated based on: (1) phosphate chemistry, (2) polymer chemistry, (3) sol-gel chemistry, and (4) the ion-exchange principle. Organo-functionalized silanes, which serve as excellent coupling and dispersion agents, are incorporated into the optimized ISPC formula and evaluated using standard ASTM testing methods and electrochemical spectroscopy. Also, an ion-exchange pigment, which leads to better adhesion by forming a mixed metal silicate surface, is

The effects to the structure and electrochemical behavior of zinc phosphate conversion coatings with ethanolamine on magnesium alloy AZ91D

International Nuclear Information System (INIS)

Li Qing; Xu Shuqiang; Hu Junying; Zhang Shiyan; Zhong Xiankang; Yang Xiaokui

2010-01-01

This paper discussed a zinc phosphate conversion coating formed on magnesium alloy AZ91D from the phosphating bath with varying amounts of ethanolamine (MEA). The effects of MEA on the form, structure, phase composition and electrochemical behavior of the phosphate coatings were examined using an scanning electron microscopy (SEM), X-ray diffraction (XRD) potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) measurements. Interpretations of the electrical elements of the equivalent circuit were obtained from the SEM structure of the coatings, assumed to be formed of two layers: an outer porous crystal layer and an inner flat amorphous layer. The result showed that adding MEA refined the microstructure of the crystal layer and that the phosphate coating, derived at the optimal content of 1.2 g/L, with the most uniform and compact outer crystal layer provided the best corrosion protection.

Carbon coated (carbonous) catalyst in ebullated bed reactor for production of oxygenated chemicals from syngas/CO2

International Nuclear Information System (INIS)

Peizheng Zhou

2002-01-01

This report summarizes the work completed under DOE's Support of Advanced Fuel Research program, Contract No. DE-FG26-99FT40681. The contract period was October 2000 through September 2002. This R and D program investigated the modification of the mechanical strength of catalyst extrudates using Hydrocarbon Technologies, Inc. (HTI) carbon-coated catalyst technology so that the ebullated bed technology can be utilized to produce valuable oxygenated chemicals from syngas/CO 2 efficiently and economically. Exothermic chemical reactions benefit from the temperature control and freedom from catalyst fouling provided by the ebullated bed reactor technology. The carbon-coated extrudates prepared using these procedures had sufficient attrition resistance and surface area for use in ebullated bed operation. The low cost of carbon coating makes the carbon-coated catalysts highly competitive in the market of catalyst extrudates

Thermo-economic evaluation and optimization of the thermo-chemical conversion of biomass into methanol

International Nuclear Information System (INIS)

Peduzzi, Emanuela; Tock, Laurence; Boissonnet, Guillaume; Maréchal, François

2013-01-01

In a carbon and resources constrained world, thermo-chemical conversion of lignocellulosic biomass into fuels and chemicals is regarded as a promising alternative to fossil resources derived products. Methanol is one potential product which can be used for the synthesis of various chemicals or as a fuel in fuel cells and internal combustion engines. This study focuses on the evaluation and optimization of the thermodynamic and economic performance of methanol production from biomass by applying process integration and optimization techniques. Results reveal the importance of the energy integration and in particular of the cogeneration of electricity for the efficient use of biomass. - Highlights: • A thermo-economic model for biomass conversion into methanol is developed. • Process integration and multi-objective optimization techniques are applied. • Results reveal the importance of energy integration for electricity co-generation

Quantitative chemical method for the determination of the disordered carbon component in pyrocarbon coatings of fuel particles

International Nuclear Information System (INIS)

Wolfrum, E.A.; Nickel, H.

1977-01-01

The chemical behavior of the surface of pyrocarbon (PyC) coatings of nuclear fuel particles was investigated in aqueous suspension by reaction with oxygen at room temperature. The concentration of the disordered material component, which has a large internal surface, can be identified by means of a pH change. Using this fact, a chemical method was developed that can be used for the quantitative determination of the concentration of this carbon component in the PyC coating

Fabrication and properties of iron-based soft magnetic composites coated with parylene via chemical vapor deposition polymerization

International Nuclear Information System (INIS)

Wu, Shen; Sun, Aizhi; Lu, Zhenwen; Cheng, Chuan

2015-01-01

This paper focuses on novel iron-based soft magnetic composites synthesis utilizing low friction factor parylene C films to coat iron powder via chemical vapor deposition polymerization. The morphology, magnetic properties, density, and chemical stability of parylene insulated iron particles were investigated. The coated parylene insulating layer was characterized by scanning electron microscopy and energy dispersive X-ray spectroscopy. The thickness of parylene C film is averagely 300 nm according to the results of transmission electron microscopy. Parylene C film uniformly coated the powder surface resulting in reducing the permeability imaginary part, increasing electrical resistivity and increasing the operating frequency of the synthesized magnets. It was shown that the parylene C coated compacts exhibited noticeably higher density compared to the epoxy resin coated compacts at the same pressure, suppress at 800 MPa increased the density by 17.02%. The result of Tafel curves indicated that the resistance of the iron particles to corrosion by NaCl solution is obviously improved after being insulated with parylene C film. - Highlights: • Parylene C uniformly coated the powder, increased the operating frequency of SMCs. • Compared with epoxy coated, the density of SMCs increased by 17.02% at 800 MPa. • The resistance of the iron particles is obviously improved with parylene film insulated

Bitumen coating as a tool for improving the porosity and chemical stability of simulated cement-waste forms

International Nuclear Information System (INIS)

Saleh, H.M.

2010-01-01

Coating process of simulated cement-based waste form with bitumen was evaluated by performing physical and chemical experimental tests. X-ray diffraction (X-RD), Fourier transform infrared spectroscopy (FT-IR) and electron microscope investigations were applied on coated and non-coated simulated waste forms. Experimental results indicated that coating process improved the applicable properties of cement-based waste form such as porosity and leachability. Diffusion coefficients and leach indecies of coated specimens were calculated and show acceptable records. It could be stated that coating cemented waste form by bitumen emulsion, isolate the radioactive contaminants, thus reduces their back release to surrounding and in consequently save the environment proper and safe

A new strategy for improvement of the corrosion resistance of a green cerium conversion coating through thermal treatment procedure before and after application of epoxy coating

Energy Technology Data Exchange (ETDEWEB)

Mahidashti, Z. [Department of Materials Engineering, Faculty of Engineering, Tarbiat Modares University, P.O. Box: 14115-143, Tehran (Iran, Islamic Republic of); Shahrabi, T., E-mail: tshahrabi34@modares.ac.ir [Department of Materials Engineering, Faculty of Engineering, Tarbiat Modares University, P.O. Box: 14115-143, Tehran (Iran, Islamic Republic of); Ramezanzadeh, B., E-mail: ramezanzadeh-bh@icrc.ac.ir [Department of Surface Coatings and Corrosion, Institute for Color Science and Technology (ICST), P.O. 16765-654, Tehran (Iran, Islamic Republic of)

2016-12-30

Highlights: • The Ce conversion coating was post-heated at various conditions. • The corrosion resistance of post-heated Ce films was evaluated. • A crack free and denser Ce film were obtained after post-heating. • The corrosion resistance of Ce film noticeably increased. • Post-heated Ce film resulted better protection performance of epoxy coating. - Abstract: The effect of post-heating of CeCC on its surface morphology and chemistry has been studied by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and contact angle (CA) measurements. The corrosion protection performance of the coatings was investigated by electrochemical impedance spectroscopy (EIS). The effect of thermal treatment of CeCC on the corrosion protection performance of epoxy coating was investigated by EIS. Results showed that the heat treatment of Ce film noticeably improved its corrosion resistance and adhesion properties compared to that of untreated samples. The CeCC deposited on the steel substrate at room temperature had a highly cracked structure, while the amount of micro-cracks significantly reduced after post-heating procedure. Results obtained from EIS analysis confirmed the effect of post-heating of CeCC on its corrosion protection performance enhancement. The increase of post-heating temperature and time up to 140 °C and 3 h led to better results.

Synthesis of Cu-coated Graphite Powders Using a Chemical Reaction Process

Energy Technology Data Exchange (ETDEWEB)

Jang, Jun-Ho; Park, Hyun-Kuk; Oh, Ik-Hyun [Korea Institute of Industrial Technology (KITECH), Gwangju (Korea, Republic of); Lim, Jae-Won [Chonbuk National University, Jeonju (Korea, Republic of)

2017-05-15

In this paper, Cu-coated graphite powders for a low thermal expansion coefficient and a high thermal conductivity are fabricated using a chemical reaction process. The Cu particles adhere to the irregular graphite powders and they homogeneously disperse in the graphite matrix. Cu-coated graphite powders are coarser at approximately 3-4 μm than the initial graphite powders; furthermore, their XRD patterns exhibit a low intensity in the oxide peak with low Zn powder content. For the passivation powders, the transposition solvent content has low values, and the XRD pattern of the oxide peaks is almost non-existent, but the high transposition solvent content does not exhibit a difference to the non-passivation treated powders.

Microstructure and corrosion performance of steam-based conversion coatings produced in the presence of TiO2 particles on aluminium alloys

DEFF Research Database (Denmark)

Din, Rameez Ud; Gudla, Visweswara Chakravarthy; Jellesen, Morten Stendahl

2016-01-01

The steam-based conversion coatings containing TiO2 particleswere prepared using a two-step process comprising of spin coating of particles onto an aluminiumsubstrate followed by a high-pressure steam treatment. Process has resulted in the formation of aluminium oxide layer (~1.3 μm thick) embedded...... to the coatings without TiO2 particles, while the shift in thepitting potential was a function of the steam treatment time and degree of particle incorporation into the oxide....... with TiO2 particles. The electrochemical measurements showthe beneficial effect of TiO2 particles in the oxide layer by exhibiting lowestanodic and cathodic activities, and reduced pit depth. The presence of TiO2 particles shifts the corrosion potentialvalues to positive side (noble side) when compared...

Mechanical properties of chemically bonded sand core materials dipped in sol-gel coating impregnated with filter

DEFF Research Database (Denmark)

Nwaogu, Ugochukwu Chibuzoh; Tiedje, Niels Skat

2012-01-01

A novel sol-gel coating impregnated with filter dust was applied on chemically bonded sand core materials by dipping. After curing, the strengths of the core materials were measured under uniaxial loading using a new strength testing machine (STM). The STM presents the loading history as a force-...... of the chemically bonded sand core materials, a combination of flexural and compression tests is suggested for improving the casting quality. © 2012 W. S. Maney & Son Ltd.......A novel sol-gel coating impregnated with filter dust was applied on chemically bonded sand core materials by dipping. After curing, the strengths of the core materials were measured under uniaxial loading using a new strength testing machine (STM). The STM presents the loading history as a force...... the strengths were increased under compression. The mode of fracture of the chemically bonded sand core materials was observed to be intergranular through the binder. The stiffness of the chemically bonded sand core materials was determined. For better understanding of the mechanical properties...

Study of chromate coatings by radioisotope tracing

International Nuclear Information System (INIS)

Drozda, T.; Maleczki, E.; Farkas, G.

1984-01-01

New radioactive tracer methods were developed to determine chromium(III) and total chromium [chromium(III)+chromium(VI)] content simultaneously. They are capable of investigating solutions and the conversion coating itself in the solid phase, respectively. The increase of chromium(III) concentration in the yellow chromate coating, and the chromium(III) to total chromium ratio in the conversion coating were determined as a function of the treating period. (author)

Layer-by-Layer Enabled Nanomaterials for Chemical Sensing and Energy Conversion

Science.gov (United States)

Paterno, Leonardo G.; Soler, Maria A. G.

2013-06-01

The layer-by-layer (LbL) technique is a wet chemical method for the assembly of ultrathin films, with thicknesses up to 100 nm. This method is based on the successive transfer of molecular layers to a solid substrate that is dipped into cationic and anionic solutions in an alternating fashion. The adsorption is mainly driven by electrostatic interactions so that many molecular and nanomaterial systems can be engineered under this method. Moreover, it is inexpensive, can be easily performed, and does not demand sophisticated equipment or clean rooms. The most explored use of the LbL technique is to build up molecular devices for chemical sensing and energy conversion. Both applications require ultrathin films where specific elements must be organized with high control of thickness and spatial distribution, preferably in the nanolength and mesolength scales. In chemical sensors, the LbL technique is employed to assemble specific sensoactive materials such as conjugated polymers, enzymes, and immunological elements onto appropriated electrodes. Molecular recognition events are thus transduced by the assembled sensoactive layer. In energy-conversion devices, the LbL technique can be employed to fabricate different device's parts including electrodes, active layers, and auxiliary layers. In both applications, the devices' performance can be fully modulated and improved by simply varying film thickness and molecular architecture. The present review article highlights the main features of the LbL technique and provides a brief description of different (bio)chemical sensors, solar cells, and organic light-emitting diodes enabled by the LbL approach.

Chrome-free Samarium-based Protective Coatings for Magnesium Alloys

Science.gov (United States)

Hou, Legan; Cui, Xiufang; Yang, Yuyun; Lin, Lili; Xiao, Qiang; Jin, Guo

The microstructure of chrome-free samarium-based conversion coating on magnesium alloy was investigated and the corrosion resistance was evaluated as well. The micro-morphology, transverse section, crystal structure and composition of the coating were observed by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive spectroscopy (EDS) and X- ray photoelectron spectroscopy (XPS), respectively. The corrosion resistance was evaluated by potentiodynamic polarization curve and electrochemical impedance spectroscopy (EIS). The results reveal that the morphology of samarium conversion coating is of crack-mud structure. Tiny cracks distribute in the compact coating deposited by samarium oxides. XRD, EDS and XPS results characterize that the coating is made of amorphous and trivalent-samarium oxides. The potentiodynamic polarization curve, EIS and OCP indicate that the samarium conversion coating can improve the corrosion resistance of magnesium alloys.

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.

Prospects of chemically deposited CoS-CU2S coatings for solar ...

African Journals Online (AJOL)

The thin films of Cu2S deposited on CoS-precoated glass substrates from chemical baths and annealed at 100oC were found to have desirable solar control characteristics superior to commercial tinted glass and magnetron sputtered multilayer metallic solar control coatings. These include: transmission spectra in the ...

Method for conversion of carbohydrate polymers to value-added chemical products

Science.gov (United States)

Zhang, Zongchao C [Norwood, NJ; Brown, Heather M [Kennewick, WA; Su, Yu [Richland, WA

2012-02-07

Methods are described for conversion of carbohydrate polymers in ionic liquids, including cellulose, that yield value-added chemicals including, e.g., glucose and 5-hydroxylmethylfurfural (HMF) at temperatures below 120.degree. C. Catalyst compositions that include various mixed metal halides are described that are selective for specified products with yields, e.g., of up to about 56% in a single step process.

Calcium phosphate formation from sea urchin - (brissus latecarinatus via modified mechano-chemical (ultrasonic conversion method

Directory of Open Access Journals (Sweden)

R. Samur

2013-07-01

Full Text Available This study aims to produce apatite structures, such as hydroxyapatite (HA and fluorapatite (FA, from precursor calcium phosphates of biological origin, namely from sea urchin, with mechano-chemical stirring and hot-plating conversion method. The produced materials were heat treated at 800 °C for 4 hours. X-ray diffraction and scanning electron microscopy (SEM studies were conducted. Calcium phosphate phases were developed. The SEM images showed the formation of micro to nano-powders. The experimental results suggest that sea urchin, Brissus latecarinatus skeleton could be an alternative source for the production of various mono or biphasic calcium phosphates with simple and economic mechano-chemical (ultrasonic conversion method.

Study on CexLa1-xO2 Buffer Layer used in Coated Conductors by Chemical Solution Method

DEFF Research Database (Denmark)

Zhao, Yue; Suo, Hongli; Grivel, Jean-Claude

2009-01-01

Developing multi-functional single buffer layer is one of the most important challenges for simplification of coated conductors configuration. Ladoped CeO2 films were prepared by chemical solution method. And surface morphology and texture quality of the La-doped CeO2 films were investigated...... method. It suggects that Ce0.9La0.1O2 film prepared by chemical solution route have a promising prospect for the simplification of coated conductors configuration....

Chemical vapor deposition of aluminide coatings on iron, nickel and superalloys

International Nuclear Information System (INIS)

John, John T.; De, P.K.; Dubey, Vivekanand; Srinivasa, Raman

2009-08-01

Aluminide coatings are a class of intermetallic coatings applied on nickel and cobalt base superalloys and steels to protect them from different forms of environmental degradation at high temperatures. In this report a CVD system that can produce the aluminide coatings on iron, nickel and nickel base alloys has been described and the result of chemical vapor deposition of aluminide coatings on iron specimens, their characterization, and property evaluation have been presented. The CVD system consists of an AlCl 3 bath, a stainless steel retort as a hot-wall reacto, cold traps and vacuum system. Aluminium chloride vapor was carried in a stream of hydrogen gas at a flow rate of 150 SCCM (standard cubic centimeter per minute) into the CVD reactor maintained in the temperature range of 1173 - 1373 K and at a pressure of 1.33 kPa (10 Torr). Aluminum deposition takes place from aluminium subchlorides produced by reaction between AlCl 3 and pure aluminum kept in the CVD reactor. The aluminum diffuses into the iron samples and iron aluminide phases are formed at the surface. The coatings were shining bright and showed good adherence to the substrate. The coatings consisted of FeAl phase over a wide range of experimental conditions. The growth kinetics of the coating followed a parabolic rate law and the mean activation energy was 212 ±16 kJ/mol. Optical microscopic studies on the transverse section of the coating showed that the aluminide coating on iron consisted of two layers. The top layer had a thickness in the range of 20-50 μm, and the under layer had thickness ranging from 35 to 250 μm depending on coating temperature in two hours. The thickness of the aluminide layer increased with coating duration and temperature. Electron microprobe studies (EPMA) showed that the aluminum concentration decreased steadily as distance from the surface increased. TEM studies showed that the outer most layer had a B2 order (of the FeAl phase), which extended even into the under

Adsorption and Desorption of Chemical Warfare Agent Simulants on Silica Surfaces with Hydrophobic Coating

International Nuclear Information System (INIS)

Park, Eun Ji; Kim, Young Dok

2013-01-01

Aim of our study is finding adsorbents suitable for pre-concentration of chemical warfare agents (CWAs). We considered Tenax, bare silica and polydimethylsiloxane (PDMS)-coated silica as adsorbents for dimethyl methylphosphonate (DMMP) and dipropylene glycol methyl ether (DPGME). Tenax showed lower thermal stability, and therefore, desorption of CWA simulants and decomposition of Tenax took place simultaneously. Silica-based adsorbents showed higher thermal stabilities than Tenax. A drawback of silica was that adsorption of CWA simulant (DMMP) was significantly reduced by pre-treatment of the adsorbents with humid air. In the case of PDMS-coated silica, influence of humidity for CWA simulant adsorption was less pronounced due to the hydrophobic nature of PDMS-coating. We propose that PDMS-coated silica can be of potential importance as adsorbent of CWAs for their pre-concentration, which can facilitate detection of these CWAs

Adsorption and Desorption of Chemical Warfare Agent Simulants on Silica Surfaces with Hydrophobic Coating

Energy Technology Data Exchange (ETDEWEB)

Park, Eun Ji; Kim, Young Dok [Sungkyunkwan Univ., Suwon (Korea, Republic of)

2013-07-15

Aim of our study is finding adsorbents suitable for pre-concentration of chemical warfare agents (CWAs). We considered Tenax, bare silica and polydimethylsiloxane (PDMS)-coated silica as adsorbents for dimethyl methylphosphonate (DMMP) and dipropylene glycol methyl ether (DPGME). Tenax showed lower thermal stability, and therefore, desorption of CWA simulants and decomposition of Tenax took place simultaneously. Silica-based adsorbents showed higher thermal stabilities than Tenax. A drawback of silica was that adsorption of CWA simulant (DMMP) was significantly reduced by pre-treatment of the adsorbents with humid air. In the case of PDMS-coated silica, influence of humidity for CWA simulant adsorption was less pronounced due to the hydrophobic nature of PDMS-coating. We propose that PDMS-coated silica can be of potential importance as adsorbent of CWAs for their pre-concentration, which can facilitate detection of these CWAs.

boron nitride coating of uranium dioxide and uranium dioxide-gadolinium oxide fuels by chemical precipitation method

International Nuclear Information System (INIS)

Uslu, I.; Tanker, E.; Guenduez, G.

1997-01-01

In this research pure urania and urania-gadolinia (5 and 10 %) fuels were coated with boron nitride (BN). This is achieved through chemical vapor deposition (CVD) using boron tricloride BCl 3 ) and ammonia (NH 3 ) at 600 C.Boron tricloride and ammonia are carried to tubular furnace using hydrogen as carrier gas. The coated samples were sintered at 1600 K. The properties of the coated samples were observed using BET surface area analysis, infrared spectra (IR), X-Ray Diffraction and Scanning Electron Microscope (SEM) techniques

Effect of chemically reduced palladium supported catalyst on sunflower oil hydrogenation conversion and selectivity

Directory of Open Access Journals (Sweden)

Abdulmajid Alshaibani

2017-02-01

Full Text Available Catalytic hydrogenation of sunflower oil was studied in order to improve the conversion and to reduce the trans-isomerization selectivity. The hydrogenation was performed using Pd–B/γ-Al2O3 prepared catalyst and Pd/Al2O3 commercial catalyst under similar conditions. The Pd–B/γ-Al2O3 catalyst was prepared by wet impregnation and chemical reduction processes. It was characterized by Brunauer–Emmett–Teller surface area analysis (BET, X-ray powder diffraction (XRD, scanning electron microscopy (SEM, and transmission electron microscopy (TEM. The result of sunflower oil hydrogenation on Pd–B/γ-Al2O3 catalyst showed a 17% higher conversion and a 23% lower trans-isomerization selectivity compared to the commercial Pd/Al2O3 catalyst. The chemical reduction of palladium supported catalyst using potassium borohydride (KBH4 has affected the Pd–B/γ-Al2O3 catalyst’s structure and particle size. These most likely influenced its catalytic performance toward higher conversion and lower trans-isomerization selectivity.

The effect of post-treatment time and temperature on cerium-based conversion coatings on Al 2024-T3

Energy Technology Data Exchange (ETDEWEB)

Heller, Daimon K [Missouri University of Science and Technology, 101 Straumanis Hall, 401 West 16th Street, Rolla, MO 65409 (United States)], E-mail: dkhvwb@mst.edu; Fahrenholtz, William G. [Missouri University of Science and Technology, 101 Straumanis Hall, 401 West 16th Street, Rolla, MO 65409 (United States)], E-mail: billf@mst.edu; O' Keefe, Matthew J. [Missouri University of Science and Technology, 101 Straumanis Hall, 401 West 16th Street, Rolla, MO 65409 (United States)

2010-02-15

Corrosion performance, morphology, and electrochemical characteristics of cerium-based conversion coatings on Al 2024-T3 were examined as a function of phosphate post-treatment time and temperature. Corrosion resistance improved after post-treatment in 2.5 wt.% NH{sub 4}H{sub 2}PO{sub 4} for times up to 10 min or temperatures up to 85 deg. C. Electrochemical impedance spectroscopy and polarization testing correlated to neutral salt spray corrosion performance. Hydrated cerium oxide and peroxide species present in the as-deposited coatings were transformed to CePO{sub 4}.H{sub 2}O for post-treatments at longer times and/or higher temperatures. Based on these results, processes active during post-treatment are kinetically dependent and strongly influenced by the post-treatment time and temperature.

Properties of plasma assisted chemical vapor deposited coatings of titanium boride on Ti--6Al--4V alloy substrates

International Nuclear Information System (INIS)

Otter, F.A.; Amisola, G.B.; Roman, W.C.; Hay, S.O.

1992-01-01

Coatings prepared in a radio-frequency-plasma (plasma assisted chemical vapor deposition) reactor employing in situ laser diagnostics have been tested and characterized. Detailed characterization studies are important to relate gas phase laser diagnostic studies and concurrent heterogeneous modeling efforts to coating characteristics. Establishing how deposition conditions are correlated with coating properties is expected to provide needed methodology for scale up of applications in the hard face protective coating area. After a brief discussion of preparation conditions and mechanical test results, we present results of chemical and physical measurements on these coatings. Measurement techniques include x-ray diffraction, Dektak surface roughness, scanning tunneling microscopy, scanning electron microscopy, and SEI, Auger electron spectroscopy, x-ray photoelectron spectroscopy, and Rutherford backscattering spectroscopy. The coatings (∼20 μm thick) are very hard (40 GPa at depths over 100 nm), adherent (60 N on scratch test), and sand erosion resistant (>40x as durable as Ti-6Al-4V). They are highly oriented with the c axis (hexagonal-close-packed) normal to the coating surface, rough (∼1 μm), and off-stoichiometry (TiB 2.2 )

Biocompatibility of Titania Nanotube Coatings Enriched with Silver Nanograins by Chemical Vapor Deposition

Directory of Open Access Journals (Sweden)

Piotr Piszczek

2017-09-01

Full Text Available Bioactivity investigations of titania nanotube (TNT coatings enriched with silver nanograins (TNT/Ag have been carried out. TNT/Ag nanocomposite materials were produced by combining the electrochemical anodization and chemical vapor deposition methods. Fabricated coatings were characterized by scanning electron microscopy (SEM, X-ray photoelectron spectroscopy (XPS, and Raman spectroscopy. The release effect of silver ions from TNT/Ag composites immersed in bodily fluids, has been studied using inductively coupled plasma mass spectrometry (ICP-MS. The metabolic activity assay (MTT was applied to determine the L929 murine fibroblasts adhesion and proliferation on the surface of TNT/Ag coatings. Moreover, the results of immunoassays (using peripheral blood mononuclear cells—PBMCs isolated from rats allowed the estimation of the immunological activity of TNT/Ag surface materials. Antibacterial activity of TNT/Ag coatings with different morphological and structural features was estimated against two Staphylococcus aureus strains (ATCC 29213 and H9. The TNT/Ag nanocomposite layers produced revealed a good biocompatibility promoting the fibroblast adhesion and proliferation. A desirable anti-biofilm activity against the S. aureus reference strain was mainly noticed for these TiO2 nanotube coatings, which contain dispersed Ag nanograins deposited on their surface.

Chemical changes in DMP1-null murine bone & silica based pecvd coatings for titanium implant osseoapplications

Science.gov (United States)

Maginot, Megen

In order to improve clinical outcomes in bone-implant systems, a thorough understanding of both local bone chemistry and implant surface chemistry is necessary. This study consists, therefore, of two main parts: one focused on determining the nature of the changes in bone chemistry in a DMP1-null transgenic disease model and the other on the development of amorphous silica-based coatings for potential use as titanium bone implant coatings. For the study of bone mineral in the DMP1 transgenic model, which is known to have low serum phosphate levels, transgenic DMP1-null and wild type mice were fed a high phosphate diet, sacrificed, and had their long bone harvested. This bone was characterized using SEM, FTIR, microCT and XANES and compared to DMP1-null and wild type control groups to assess the therapeutic effect of high Pi levels on the phenotype and the role of DMP1 in mineralization in vivo. Findings suggest that though the high phosphate diet results in restoring serum phosphate levels, it does not completely rescue the bone mineral phenotype at an ultrastructural level and implicates DMP1 in phosphate nucleation. Since plasma enhanced chemical vapor deposition (PECVD) silica like coatings have not previously been fabricated for use in oessoapplications, the second part of this study initially focused on the characterization of novel SiOx chemistries fabricated via a chemical vapor deposition process that were designed specifically to act as bioactive coatings with a loose, hydrogenated structure. These coatings were then investigated for their potential initial stage response to bone tissue through immersion in a simulated body fluid and through the culture of MC3T3 cells on the coating surfaces. Coating surfaces were characterized by SEM, FTIR, contact angle measurements, and XANES. Coating dissolution and ionic release were also investigated by ICP-OES. Findings suggest that some SiOx chemistries may form a bioactive coating while more highly substituted

A solid-state nuclear magnetic resonance study of post-plasma reactions in organosilicone microwave plasma-enhanced chemical vapor deposition (PECVD) coatings.

Science.gov (United States)

Hall, Colin J; Ponnusamy, Thirunavukkarasu; Murphy, Peter J; Lindberg, Mats; Antzutkin, Oleg N; Griesser, Hans J

2014-06-11

Plasma-polymerized organosilicone coatings can be used to impart abrasion resistance and barrier properties to plastic substrates such as polycarbonate. Coating rates suitable for industrial-scale deposition, up to 100 nm/s, can be achieved through the use of microwave plasma-enhanced chemical vapor deposition (PECVD), with optimal process vapors such as tetramethyldisiloxane (TMDSO) and oxygen. However, it has been found that under certain deposition conditions, such coatings are subject to post-plasma changes; crazing or cracking can occur anytime from days to months after deposition. To understand the cause of the crazing and its dependence on processing plasma parameters, the effects of post-plasma reactions on the chemical bonding structure of coatings deposited with varying TMDSO-to-O2 ratios was studied with (29)Si and (13)C solid-state magic angle spinning nuclear magnetic resonance (MAS NMR) using both single-pulse and cross-polarization techniques. The coatings showed complex chemical compositions significantly altered from the parent monomer. (29)Si MAS NMR spectra revealed four main groups of resonance lines, which correspond to four siloxane moieties (i.e., mono (M), di (D), tri (T), and quaternary (Q)) and how they are bound to oxygen. Quantitative measurements showed that the ratio of TMDSO to oxygen could shift the chemical structure of the coating from 39% to 55% in Q-type bonds and from 28% to 16% for D-type bonds. Post-plasma reactions were found to produce changes in relative intensities of (29)Si resonance lines. The NMR data were complemented by Fourier transform infrared (FTIR) spectroscopy. Together, these techniques have shown that the bonding environment of Si is drastically altered by varying the TMDSO-to-O2 ratio during PECVD, and that post-plasma reactions increase the cross-link density of the silicon-oxygen network. It appears that Si-H and Si-OH chemical groups are the most susceptible to post-plasma reactions. Coatings produced at a

Research on chemical vapor deposition processes for advanced ceramic coatings

Science.gov (United States)

Rosner, Daniel E.

1993-01-01

Our interdisciplinary background and fundamentally-oriented studies of the laws governing multi-component chemical vapor deposition (VD), particle deposition (PD), and their interactions, put the Yale University HTCRE Laboratory in a unique position to significantly advance the 'state-of-the-art' of chemical vapor deposition (CVD) R&D. With NASA-Lewis RC financial support, we initiated a program in March of 1988 that has led to the advances described in this report (Section 2) in predicting chemical vapor transport in high temperature systems relevant to the fabrication of refractory ceramic coatings for turbine engine components. This Final Report covers our principal results and activities for the total NASA grant of $190,000. over the 4.67 year period: 1 March 1988-1 November 1992. Since our methods and the technical details are contained in the publications listed (9 Abstracts are given as Appendices) our emphasis here is on broad conclusions/implications and administrative data, including personnel, talks, interactions with industry, and some known applications of our work.

Vanadium diffusion coating on HT-9 cladding for mitigating the fuel cladding chemical interactions

Science.gov (United States)

Lo, Wei-Yang; Yang, Yong

2014-08-01

Fuel cladding chemical interaction (FCCI) has been identified as one of the crucial issues for developing Ferritic/Martensitic (F/M) stainless steel claddings for metallic fuels in a fast reactor. The anticipated elevated temperature and high neutron flux can significantly aggravate the FCCI, in terms of formation of inter-diffusion and lower melting point eutectic phases. To mitigate the FCCI, vanadium carbide coating as a diffusion barrier was deposited on the HT-9 substrate using a pack cementation diffusion coating (PCDC) method, and the processing temperature was optimized down to 730 °C. A solid metallurgical bonding between the coating layer and substrate was achieved, and the coating is free from through depth cracks. The microstructural characterizations using SEM and TEM show a nanostructured grain structure. EDS/WDS and XRD analysis confirm the phase of coating layer as V2C. Diffusion couple tests at 660 °C for 100 h demonstrate that V2C layer with a thickness of less than 5 μm can effectively eliminate the inter-diffusion between the lanthanide cerium and HT-9 steel.

Vanadium diffusion coating on HT-9 cladding for mitigating the fuel cladding chemical interactions

Energy Technology Data Exchange (ETDEWEB)

Lo, Wei-Yang; Yang, Yong, E-mail: yongyang@ufl.edu

2014-08-01

Fuel cladding chemical interaction (FCCI) has been identified as one of the crucial issues for developing Ferritic/Martensitic (F/M) stainless steel claddings for metallic fuels in a fast reactor. The anticipated elevated temperature and high neutron flux can significantly aggravate the FCCI, in terms of formation of inter-diffusion and lower melting point eutectic phases. To mitigate the FCCI, vanadium carbide coating as a diffusion barrier was deposited on the HT-9 substrate using a pack cementation diffusion coating (PCDC) method, and the processing temperature was optimized down to 730 °C. A solid metallurgical bonding between the coating layer and substrate was achieved, and the coating is free from through depth cracks. The microstructural characterizations using SEM and TEM show a nanostructured grain structure. EDS/WDS and XRD analysis confirm the phase of coating layer as V{sub 2}C. Diffusion couple tests at 660 °C for 100 h demonstrate that V{sub 2}C layer with a thickness of less than 5 μm can effectively eliminate the inter-diffusion between the lanthanide cerium and HT-9 steel.

Influence of acids on the zinc conversion process with molybdate

International Nuclear Information System (INIS)

Silva, Cosmelina Goncalves da; Margarit-Mattos, Isabel Cristina Pereira; Mattos, Oscar Rosa; Barcia, Oswaldo Esteves

2010-01-01

Molybdate conversion coatings have been evaluated as possible alternative to the chromate ones. The acid used in the pH adjustment of the conversion baths exerts great influence on the anti corrosive properties of these coatings. The aim of this work was to verify the role of phosphoric and sulfuric acids on the zinc conversion process with molybdate. The techniques used were: chronopotentiometry, electrochemical impedance spectroscopy (EIS) and interfacial pH measurements. The surface characterization was made with scanning electron microscopy (SEM) and energy dispersive X-ray (EDX). The chronopotentiometry results have shown that the influence of the variation of the electrode rotation speed on the conversion process is acid-dependent: the acid influences the mass transport during the conversion. The EIS measures have suggested that the conversion mechanism does not change with the acid, being the coatings thicker when H_2SO_4 is used than the obtained with H_3PO_4. The pH interfacial results have shown a pH increase more significant for the bath with H_2SO_4, indicating a fastest kinetic of zinc dissolution. It was identified the presence of Mo in all analyzed coatings, for both acids, and P in those obtained with H_3PO_4. (author)

Atomic Layer Deposition of Chemical Passivation Layers and High Performance Anti-Reflection Coatings on Back-Illuminated Detectors

Science.gov (United States)

Hoenk, Michael E. (Inventor); Greer, Frank (Inventor); Nikzad, Shouleh (Inventor)

2014-01-01

A back-illuminated silicon photodetector has a layer of Al2O3 deposited on a silicon oxide surface that receives electromagnetic radiation to be detected. The Al2O3 layer has an antireflection coating deposited thereon. The Al2O3 layer provides a chemically resistant separation layer between the silicon oxide surface and the antireflection coating. The Al2O3 layer is thin enough that it is optically innocuous. Under deep ultraviolet radiation, the silicon oxide layer and the antireflection coating do not interact chemically. In one embodiment, the silicon photodetector has a delta-doped layer near (within a few nanometers of) the silicon oxide surface. The Al2O3 layer is expected to provide similar protection for doped layers fabricated using other methods, such as MBE, ion implantation and CVD deposition.

The adhesion performance of epoxy coating on AA6063 treated in Ti/Zr/V based solution

International Nuclear Information System (INIS)

Zhu, Wen; Li, Wenfang; Mu, Songlin; Yang, Yunyu; Zuo, Xi

2016-01-01

Highlights: • A non-chrome titanium/zirconium/vanadium-based (Ti/Zr/V) conversion coating is prepared on AA6063 at room temperature. • The Ti/Zr/V conversion coating is produced on AA6063 within 50 s. • The adhesion strength between epoxy coating and AA6063 is improved significantly after the Ti/Zr/V conversion treatment. - Abstract: An environment-friendly titanium/zirconium/vanadium-based (Ti/Zr/V) conversion coating was prepared on aluminum alloy 6063 (AA6063). The epoxy powder coatings were applied on the AA6063 samples with/without Ti/Zr/V conversion coatings via electrostatic spraying. The morphology and composition of the conversion coating were studied by scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS), respectively. The surface free energy components of AA6063 samples were measured by a static contact angle measuring device with Owens method. The adhesion properties of the epoxy coating on AA6063 treated with different conversion times were evaluated using a pull-off tester. The Ti/Zr/V conversion coating was mainly composed of metal oxide (TiO 2 , ZrO 2 , V 2 O 5 , Al 2 O 3 , etc.), metal fluoride (ZrF 4 , AlF 3 , etc.) and metal organic complex. The formation time of this conversion coating was reduced to 50 s. After such surface treatment, the samples' surface roughness was increased and the contact angle with water was decreased. Both the surface free energy and the work of adhesion were increased. The adhesion strength between the epoxy coating and AA6063 was enhanced significantly.

Modelling of solar cells with down-conversion of high energy photons, anti-reflection coatings and light trapping

International Nuclear Information System (INIS)

Vos, Alexis de; Szymanska, Aleksandra; Badescu, Viorel

2009-01-01

In classical solar cells, each absorbed photon gives rise to one electron-hole pair, irrespective of the photon energy. By applying an appropriate photoluminescent layer in front of the solar cell semiconductor, one can convert one high energy photon into two low energy photons (so-called down-conversion). In the present study, we do not consider photoluminescent layers that merely shift down photon energies (without enhancing the number of photons). In principle, these two photons can then generate two electron-hole pairs in the solar cell, thus increasing the efficiency of the device. However, the two photons emitted by the converter, are not necessarily emitted in the direction of the semiconductor: they can also be emitted in the direction 'back to the sun'. As most semiconductors have a high refractive index, in case the luminescent material has a low refractive index, more than half of the photoluminescence emission is lost in the sun direction, resulting in a net loss of light current generated by the solar cell instead of an increase. On the other hand, a high refractive index of the conversion layer (e.g. equal to the solar cell refractive index) will lead to a bad optical coupling with the air and a good optical coupling with the semiconductor, and therefore, more than 50% of the emitted low energy photons will actually reach the solar cell. However, in the latter case, many solar photons do not reach the converter in the first place because of reflection at the air-converter interface. As a result, it turns out that, in the absence of any anti-reflection coating, a refractive index n 2 of the converting layer in the range between n 1 1/2 and n 1 is optimal, where n 1 is the refractive index of the solar cell material. If, however, an anti-reflection coating is applied between air and the converter, the best choice for n 2 is n 1 . Finally, if two anti-reflection coatings are applied (the former between air and the converter, the latter between the

Up-conversion luminescence application in Er3+: TiO2 thin film prepared by dip coating sol-gel route

International Nuclear Information System (INIS)

Badr, Y.; Battisha, I.K.; Salah, A.; Salem, M.A.

2008-01-01

Sol-gel derived nano-crystalline titanium dioxide films doped with 1 up to 5% Er 3+ ions were prepared by dip coating sol-gel method. The coating sol was obtained by hydrolysis of Ti(OC 4 H 9 ) 4 in ethanol/HCI solution. The FT-Raman and the X-ray diffraction (XRD) were carried out to determine the crystal structure of the prepared samples. The morphology SEM and the cross-sectional of the film were used to characterize the microstructure and the thickness of the prepared film. It is shown that relative homogeneous, crack-free and transparent film was achieved via dipping process at 500 deg C. After the excitation with laser diode at wavelength 808 nm, visible (Vis) and infrared (IR) up-conversion emissions were evidenced in the thin film samples under investigation. The up-conversion was found to depend strongly on the Er 3+ ion concentrations. The visible emission was found to be at 540, 560, 590 and 640 nm for thin film. They are attributed to intra-4f transition of Er 3+ ions and assigned to the ( 2 H 11/2 + 4 S 3/2 ) and 4 F 9/2 , which are populated through excited state absorption (ESA) for 808 nm excitation. (author)

Green chemicals : A Kinetic Study on the Conversion of Glucose to Levulinic Acid

NARCIS (Netherlands)

Girisuta, B.; Janssen, L.P.B.M.; Heeres, H.J.

2006-01-01

Levulinic acid has been identified as a promising green, biomass derived platform chemical. A kinetic study on one of the key steps in the conversion of biomass to levulinic acid, i.e., the acid catalysed decomposition of glucose to levulinic acid has been performed. The experiments were performed

Influence of silane films in the zinc coating post-treatment

International Nuclear Information System (INIS)

Costa, Marlla Vallerius da; Menezes, Tiago Lemos; Malfatti, Celia de Fraga; Muller, Iduvirges Lourdes; Oliveira, Claudia Trindade; Bonino, Jean-Pierre

2009-01-01

The sol-gel process based on silanes precursors appeared in recent years as a strong alternative for post-treatment to provide an optimization of the protective efficacy of zinc. Moreover, this process has been used to replace chemical chromating conversion based on hexavalent chromium. The silane films are hybrid compounds that provide characteristics of both polymeric materials, such as flexibility and functional compatibility, and ceramic materials, such as high strength and durability. The present work aimed to evaluate the influence of silane films obtained by dip-coating, on the characteristics of electrodeposited zinc coatings. The xerogel films showed a homogeneous surface and a better performance on the corrosion resistance than zinc coating without post-treatment, what can be confirmed by the electrochemical impedance results. These tests showed that application of the silane film promotes the occurrence of one more time constant compared to pure zinc system, hindering the corrosion process. (author)

The adhesion performance of epoxy coating on AA6063 treated in Ti/Zr/V based solution

Energy Technology Data Exchange (ETDEWEB)

Zhu, Wen; Li, Wenfang, E-mail: mewfli@scut.edu.cn; Mu, Songlin; Yang, Yunyu; Zuo, Xi

2016-10-30

Highlights: • A non-chrome titanium/zirconium/vanadium-based (Ti/Zr/V) conversion coating is prepared on AA6063 at room temperature. • The Ti/Zr/V conversion coating is produced on AA6063 within 50 s. • The adhesion strength between epoxy coating and AA6063 is improved significantly after the Ti/Zr/V conversion treatment. - Abstract: An environment-friendly titanium/zirconium/vanadium-based (Ti/Zr/V) conversion coating was prepared on aluminum alloy 6063 (AA6063). The epoxy powder coatings were applied on the AA6063 samples with/without Ti/Zr/V conversion coatings via electrostatic spraying. The morphology and composition of the conversion coating were studied by scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS), respectively. The surface free energy components of AA6063 samples were measured by a static contact angle measuring device with Owens method. The adhesion properties of the epoxy coating on AA6063 treated with different conversion times were evaluated using a pull-off tester. The Ti/Zr/V conversion coating was mainly composed of metal oxide (TiO{sub 2}, ZrO{sub 2}, V{sub 2}O{sub 5}, Al{sub 2}O{sub 3}, etc.), metal fluoride (ZrF{sub 4}, AlF{sub 3}, etc.) and metal organic complex. The formation time of this conversion coating was reduced to 50 s. After such surface treatment, the samples' surface roughness was increased and the contact angle with water was decreased. Both the surface free energy and the work of adhesion were increased. The adhesion strength between the epoxy coating and AA6063 was enhanced significantly.

Development of antimicrobial coating by later-by-layer dip coating of chlorhexidine-loaded micelles.

Science.gov (United States)

Tambunlertchai, Supreeda; Srisang, Siriwan; Nasongkla, Norased

2017-06-01

Layer-by-layer (LbL) dip coating, accompanying with the use of micelle structure, allows hydrophobic molecules to be coated on medical devices' surface via hydrogen bonding interaction. In addition, micelle structure also allows control release of encapsulated compound. In this research, we investigated methods to coat and maximize the amount of chlorhexidine (CHX) on silicone surface through LbL dip coating method utilizing hydrogen bonding interaction between PEG on micelle corona and PAA. The number of coated cycles was varied in the process and 90 coating cycles provided the maximum amount of CHX loaded onto the surface. In addition, pre-coating the surface with PAA enhanced the amount of coated CHX by 20%. Scanning electron microscope (SEM) and Fourier Transform Infrared Spectroscopy (FTIR) were used to validate and characterize the coating. For control release aspect, the coated film tended to disrupt at physiological condition; hence chemical crosslinking was performed to minimize the disruption and maximize the release time. Chemical crosslinking at pH 2.5 and 4.5 were performed in the process. It was found that chemical crosslinking could help extend the release period up to 18 days. This was significantly longer when compared to the non-crosslinking silicone tube that could only prolong the release for 5 days. In addition, chemical crosslinking at pH 2.5 gave higher and better initial burst release, release period and antimicrobial properties than that of pH 4.5 or the normal used pH for chemical crosslinking process.

Tantalum coating on porous Ti6Al4V scaffold using chemical vapor deposition and preliminary biological evaluation

Energy Technology Data Exchange (ETDEWEB)

Li, Xiang, E-mail: xiangliwj@sjtu.edu.cn [School of Mechanical Engineering, Shanghai Jiao Tong University, State Key Laboratory of Mechanical System and Vibration, Shanghai, 200240 (China); Wang, Lin [Institute of Orthopaedics, Xijing Hospital, The Fourth Military Medical University, Xi' an, 710032 (China); Yu, Xiaoming [The Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110016 (China); Feng, Yafei [Institute of Orthopaedics, Xijing Hospital, The Fourth Military Medical University, Xi' an, 710032 (China); Wang, Chengtao [School of Mechanical Engineering, Shanghai Jiao Tong University, State Key Laboratory of Mechanical System and Vibration, Shanghai, 200240 (China); Yang, Ke [The Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110016 (China); Su, Daniel [School of Mechanical Engineering, Shanghai Jiao Tong University, State Key Laboratory of Mechanical System and Vibration, Shanghai, 200240 (China)

2013-07-01

Porous tantalum (Ta), produced via chemical vapor deposition (CVD) of commercially pure Ta onto a vitreous carbon, is currently available for use in orthopedic applications. However, the relatively high manufacturing cost and the incapability to produce customized implant using medical image data have limited its application to gain widespread acceptance. In this study, Ta film was deposited on porous Ti6Al4V scaffolds using CVD technique. Digital microscopy and scanning electron microscopy indicated that the Ta coating evenly covered the entire scaffold structure. X-ray diffraction analysis showed that the coating consisted of α and β phases of Ta. Goat mesenchymal stem cells were seeded and cultured on the Ti6Al4V scaffolds with and without coating. The tetrazolium-based colorimetric assay exhibited better cell adhesion and proliferation on Ta-coated scaffolds compared with uncoated scaffolds. The porous scaffolds were subsequently implanted in goats for 12 weeks. Histological analysis revealed similar bone formation around the periphery of the coated and uncoated implants, but bone ingrowth is better within the Ta-coated scaffolds. To demonstrate the ability of producing custom implant for clinical applications via this technology, we designed and fabricated a porous Ti6Al4V scaffold with segmental mandibular shape derived from patient computerized tomography data. - Highlights: • Ta film was coated on porous Ti6Al4V scaffold using chemical vapor deposition. • Tantalum coating allowed for higher levels of cell adhesion and proliferation. • Better new bone formation occurred inside the tantalum-coated scaffolds. • Clinical image data was integrated with EBM to fabricate customized scaffold.

Tantalum coating on porous Ti6Al4V scaffold using chemical vapor deposition and preliminary biological evaluation

International Nuclear Information System (INIS)

Li, Xiang; Wang, Lin; Yu, Xiaoming; Feng, Yafei; Wang, Chengtao; Yang, Ke; Su, Daniel

2013-01-01

Porous tantalum (Ta), produced via chemical vapor deposition (CVD) of commercially pure Ta onto a vitreous carbon, is currently available for use in orthopedic applications. However, the relatively high manufacturing cost and the incapability to produce customized implant using medical image data have limited its application to gain widespread acceptance. In this study, Ta film was deposited on porous Ti6Al4V scaffolds using CVD technique. Digital microscopy and scanning electron microscopy indicated that the Ta coating evenly covered the entire scaffold structure. X-ray diffraction analysis showed that the coating consisted of α and β phases of Ta. Goat mesenchymal stem cells were seeded and cultured on the Ti6Al4V scaffolds with and without coating. The tetrazolium-based colorimetric assay exhibited better cell adhesion and proliferation on Ta-coated scaffolds compared with uncoated scaffolds. The porous scaffolds were subsequently implanted in goats for 12 weeks. Histological analysis revealed similar bone formation around the periphery of the coated and uncoated implants, but bone ingrowth is better within the Ta-coated scaffolds. To demonstrate the ability of producing custom implant for clinical applications via this technology, we designed and fabricated a porous Ti6Al4V scaffold with segmental mandibular shape derived from patient computerized tomography data. - Highlights: • Ta film was coated on porous Ti6Al4V scaffold using chemical vapor deposition. • Tantalum coating allowed for higher levels of cell adhesion and proliferation. • Better new bone formation occurred inside the tantalum-coated scaffolds. • Clinical image data was integrated with EBM to fabricate customized scaffold

Dual-enhanced photothermal conversion properties of reduced graphene oxide-coated gold superparticles for light-triggered acoustic and thermal theranostics

Science.gov (United States)

Lin, Li-Sen; Yang, Xiangyu; Niu, Gang; Song, Jibin; Yang, Huang-Hao; Chen, Xiaoyuan

2016-01-01

A rational design of highly efficient photothermal agents that possess excellent light-to-heat conversion properties is a fascinating topic in nanotheranostics. Herein, we present a facile route to fabricate size-tunable reduced graphene oxide (rGO)-coated gold superparticles (rGO-GSPs) and demonstrate their dual-enhanced photothermal conversion properties for photoacoustic imaging and photothermal therapy. For the first time, graphene oxide (GO) was directly used as an emulsifying agent for the preparation of gold superparticles (GSPs) with near-infrared absorption by the emulsion method. Moreover, GO spontaneously deposited on the surface of GSPs could also act as the precursor of the rGO shell. Importantly, both the plasmonic coupling of the self-assembled gold nanoparticles and the interaction between GSPs and rGO endow rGO-GSPs with enhanced photothermal conversion properties, allowing rGO-GSPs to be used for sensitive photoacoustic detection and efficient photothermal ablation of tumours in vivo. This study provides a facile approach to prepare colloidal superparticles-graphene hybrid nanostructures and will pave the way toward the design and optimization of photothermal nanomaterials with improved properties for theranostic applications.A rational design of highly efficient photothermal agents that possess excellent light-to-heat conversion properties is a fascinating topic in nanotheranostics. Herein, we present a facile route to fabricate size-tunable reduced graphene oxide (rGO)-coated gold superparticles (rGO-GSPs) and demonstrate their dual-enhanced photothermal conversion properties for photoacoustic imaging and photothermal therapy. For the first time, graphene oxide (GO) was directly used as an emulsifying agent for the preparation of gold superparticles (GSPs) with near-infrared absorption by the emulsion method. Moreover, GO spontaneously deposited on the surface of GSPs could also act as the precursor of the rGO shell. Importantly, both the

Bioelectrochemical Integration of Waste Heat Recovery, Waste-to- Energy Conversion, and Waste-to-Chemical Conversion with Industrial Gas and Chemical Manufacturing Processes

Energy Technology Data Exchange (ETDEWEB)

Mac Dougall, James [Air Products and Chemicals, Inc., Allentown, PA (United States)

2016-02-05

Many U.S. manufacturing facilities generate unrecovered, low-grade waste heat, and also generate or are located near organic-content waste effluents. Bioelectrochemical systems, such as microbial fuel cells and microbial electrolysis cells, provide a means to convert organic-content effluents into electric power and useful chemical products. A novel biochemical electrical system for industrial manufacturing processes uniquely integrates both waste heat recovery and waste effluent conversion, thereby significantly reducing manufacturing energy requirements. This project will enable the further development of this technology so that it can be applied across a wide variety of US manufacturing segments, including the chemical, food, pharmaceutical, refinery, and pulp and paper industries. It is conservatively estimated that adoption of this technology could provide nearly 40 TBtu/yr of energy, or more than 1% of the U.S. total industrial electricity use, while reducing CO₂ emissions by more than 6 million tons per year. Commercialization of this technology will make a significant contribution to DOE’s Industrial Technology Program goals for doubling energy efficiency and providing a more robust and competitive domestic manufacturing base.

Characteristics and corrosion studies of vanadate conversion coating formed on Mg–14 wt%Li–1 wt%Al–0.1 wt%Ce alloy

International Nuclear Information System (INIS)

Ma Yibin; Li Ning; Li Deyu; Zhang Milin; Huang Xiaomei

2012-01-01

Highlights: ► Vanadate film forms on the surface of Mg–Li–Al–Ce alloy. ► Vanadate coating improves the corrosion resistance. ► Vanadate coating is composed of Mg(OH) 2 , Li 2 O and V 2 O 5 . - Abstract: Mg–14Li–1Al–0.1Ce alloy is immersed in NH 4 VO 3 + K 3 (Fe(CN) 6 ) solutions with different NH 4 VO 3 and/or K 3 (Fe(CN) 6 ) concentrations, and different immersion time. The surface morphology and composition of the vanadate coating are then characterized by scanning electron microscopy with energy dispersion spectroscopy (SEM-EDS) and X-ray photoelectron spectroscopy (XPS), and the corrosion behavior of the conversion coating is studied by polarization technique and electrochemical impedance spectroscopy (EIS). The experimental results indicate that the vanadate film with better corrosion resistance forms on Mg–Li–Al–Ce surface after the sample is immersed in 30 g L −1 NH 4 VO 3 + 3.75 g L −1 K 3 (Fe(CN) 6 ) solution at 80 °C for 10 min. The coating consists of V 2 O 5 , Li 2 O and Mg(OH) 2 .

Cerium oxide as conversion coating for the corrosion protection of aluminum

Directory of Open Access Journals (Sweden)

JELENA GULICOVSKI

2013-11-01

Full Text Available CeO2 coatings were formed on the aluminum after Al surface preparation, by dripping the ceria sol, previously prepared by forced hydrolysis of Ce(NO34. The anticorrosive properties of ceria coatings were investigated by the electrochemical impedance spectroscopy (EIS during the exposure to 0.03 % NaCl. The morphology of the coatings was examined by the scanning electron microscopy (SEM. EIS data indicated considerably larger corrosion resistance of CeO2-coated aluminum than for bare Al. The corrosion processes on Al below CeO2 coating are subjected to more pronounced diffusion limitations in comparison to the processes below passive aluminum oxide film, as the consequence of the formation of highly compact protective coating. The results show that the deposition of ceria coatings is an effective way to improve corrosion resistance for aluminum.

Comparison study of different coatings on degradation performance and cell response of Mg-Sr alloy

International Nuclear Information System (INIS)

Shangguan, Yongming; Sun, Lina; Wan, Peng; Tan, Lili; Wang, Chengyue; Fan, Xinmin; Qin, Ling; Yang, Ke

2016-01-01

To solve the problem of rapid degradation for magnesium-based implants, surface modification especially coating method is widely studied and showed the great potential for clinical application. However, as concerned to the further application and medical translation for biodegradable magnesium alloys, there are still lack of data and comparisons among different coatings on their degradation and biological properties. This work studied three commonly used coatings on Mg-Sr alloy, including micro-arc oxidation coating, electrodeposition coating and chemical conversion coating, and compared these coatings for requirements of favorable degradation and biological performances, how each of these coating systems has performed. Finally the mechanism for the discrepancy between these coatings is proposed. The results indicate that the micro-arc oxidation coating on Mg-Sr alloy exhibited the best corrosion resistance and cell response among these coatings, and is proved to be more suitable for the orthopedic application. - Highlights: • The MAO, PED and Sr-P coating were fabricated on Mg-Sr alloy to evaluate the degradation. • The MAO coating showed the greatest degradation performance among these three coatings. • The PED coating exhibited worse corrosion resistance even than Mg-Sr substrate. • The value of cell proliferation and ALP activity were ranked in the following order: MAO > Sr-P > PED.

Comparison study of different coatings on degradation performance and cell response of Mg-Sr alloy

Energy Technology Data Exchange (ETDEWEB)

Shangguan, Yongming [Department of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China); Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China); Sun, Lina [Jinzhou Medical University, Jinzhou 121000 (China); Wan, Peng, E-mail: pwan@imr.ac.cn [Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China); Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Hong Kong SAR (China); Tan, Lili [Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China); Wang, Chengyue [Jinzhou Medical University, Jinzhou 121000 (China); Fan, Xinmin [Department of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China); Qin, Ling [Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Hong Kong SAR (China); Yang, Ke, E-mail: kyang@imr.ac.cn [Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China)

2016-12-01

To solve the problem of rapid degradation for magnesium-based implants, surface modification especially coating method is widely studied and showed the great potential for clinical application. However, as concerned to the further application and medical translation for biodegradable magnesium alloys, there are still lack of data and comparisons among different coatings on their degradation and biological properties. This work studied three commonly used coatings on Mg-Sr alloy, including micro-arc oxidation coating, electrodeposition coating and chemical conversion coating, and compared these coatings for requirements of favorable degradation and biological performances, how each of these coating systems has performed. Finally the mechanism for the discrepancy between these coatings is proposed. The results indicate that the micro-arc oxidation coating on Mg-Sr alloy exhibited the best corrosion resistance and cell response among these coatings, and is proved to be more suitable for the orthopedic application. - Highlights: • The MAO, PED and Sr-P coating were fabricated on Mg-Sr alloy to evaluate the degradation. • The MAO coating showed the greatest degradation performance among these three coatings. • The PED coating exhibited worse corrosion resistance even than Mg-Sr substrate. • The value of cell proliferation and ALP activity were ranked in the following order: MAO > Sr-P > PED.

X-ray texture analysis of paper coating pigments and the correlation with chemical composition analysis

Science.gov (United States)

Roine, J.; Tenho, M.; Murtomaa, M.; Lehto, V.-P.; Kansanaho, R.

2007-10-01

The present research experiments the applicability of x-ray texture analysis in investigating the properties of paper coatings. The preferred orientations of kaolin, talc, ground calcium carbonate, and precipitated calcium carbonate particles used in four different paper coatings were determined qualitatively based on the measured crystal orientation data. The extent of the orientation, namely, the degree of the texture of each pigment, was characterized quantitatively using a single parameter. As a result, the effect of paper calendering is clearly seen as an increase on the degree of texture of the coating pigments. The effect of calendering on the preferred orientation of kaolin was also evident in an independent energy dispersive spectrometer analysis on micrometer scale and an electron spectroscopy for chemical analysis on nanometer scale. Thus, the present work proves x-ray texture analysis to be a potential research tool for characterizing the properties of paper coating layers.

Chemical coal conversion yesterday, today, and tomorrow; Der Chemierohstoff Kohle: gestern, heute und morgen

Energy Technology Data Exchange (ETDEWEB)

Talbiersky, J. [UCP Chemicals AG, Wien (Austria)

2007-01-15

Shortage in mineral oil and gas as well as a high price level have caused a renaissance in coal conversion technologies, at the end of the 70's. Today we have a similar situation. Now coal coversion technologies will be in the focus again but hopefully as a longterm strategy. The most important coal conversion technologies as liquefaction, gasification, coking and calcium carbide synthesis are discussed regarding their use for the production of chemicals. The most important source for aromatic chemicals from coal is till now coal tar with an availability of 22 Mio. t/a. The manufacturing of coal tar is discussed as an example for making aromatic products from a complex feed stock that you get by the fixed bed gasification, coal liquefaction and coking. Also the special marketing strategy that is necessary to be competitive against products from the petroindustry. It can be expected, that coal gasification as a source for synthesis gas will become more and more important. Synthesis gas is the access to aliphatic hydrocarbons by Fischer Tropsch synthesis and to methanol, a chemical with a high synthetic potential. Also the new hydrothermal carbonization of biomass to synthetic coal is mentioned. (orig.)

Highly Conductive One-Dimensional Manganese Oxide Wires by Coating with Graphene Oxides

Science.gov (United States)

Tojo, Tomohiro; Shinohara, Masaki; Fujisawa, Kazunori; Muramatsu, Hiroyuki; Hayashi, Takuya; Ahm Kim, Yoong; Endo, Morinobu

2012-10-01

Through coating with graphene oxides, we have developed a chemical route to the bulk production of long, thin manganese oxide (MnO2) nanowires that have high electrical conductivity. The average diameter of these hybrid nanowires is about 25 nm, and their average length is about 800 nm. The high electrical conductivity of these nanowires (ca. 189.51+/-4.51 µS) is ascribed to the homogeneous coating with conductive graphene oxides as well as the presence of non-bonding manganese atoms. The growth mechanism of the nanowires is theoretically supported by the initiation of morphological conversion from graphene oxide to wrapped structures through the formation of covalent bonds between manganese and oxygen atoms at the graphene oxide edge.

Effect of biomass feedstock chemical and physical properties on energy conversion processes: Volume 2, Appendices

Energy Technology Data Exchange (ETDEWEB)

Butner, R.S.; Elliott, D.C.; Sealock, L.J., Jr.; Pyne, J.W.

1988-12-01

This report presents an exploration of the relationships between biomass feedstocks and the conversion processes that utilize them. Specifically, it discusses the effect of the physical and chemical structure of biomass on conversion yields, rates, and efficiencies in a wide variety of available or experimental conversion processes. A greater understanding of the complex relationships between these conversion systems and the production of biomass for energy uses is required to help optimize the complex network of biomass production, collection, transportation, and conversion to useful energy products. The review of the literature confirmed the scarcity of research aimed specifically at identifying the effect of feedstock properties on conversion. In most cases, any mention of feedstock-related effects was limited to a few brief remarks (usually in qualitative terms) in the conclusions, or as a topic for further research. Attempts to determine the importance of feedstock parameters from published data were further hampered by the lack of consistent feedstock characterization and the difficulty of comparing results between different experimental systems. Further research will be required to establish quantitative relationships between feedstocks and performance criteria in conversion. 127 refs., 4 figs., 7 tabs.

The effect of surface pre-conditioning treatments on the local composition of Zr-based conversion coatings formed on aluminium alloys

Science.gov (United States)

Cerezo, J.; Vandendael, I.; Posner, R.; de Wit, J. H. W.; Mol, J. M. C.; Terryn, H.

2016-03-01

This study investigates the effect of different alkaline, acidic and thermal pre-conditioning treatments applied to different Al alloy surfaces. The obtained results are compared to the characteristics of Zr-based conversion coatings that were subsequently generated on top of these substrates. Focus is laid on typical elemental distributions on the sample surfaces, in particular on the amount of precipitated functional additives such as Cu species that are present in the substrate matrix as well as in the conversion bath solutions. To this aim, Field Emission Auger Electron spectra, depth profiles and surface maps with superior local resolution were acquired and compared to scanning electron microscopy images of the sample. The results show how de-alloying processes, which occur at and around intermetallic particles in the Al matrix during typical industrial alkaline or acidic cleaning procedures, provide a significant source of crystallization cores for any following coating processes. This is in particular due for Cu-species, as the resulting local Cu structures on the surface strongly affect the film formation and compositions of state-of-the-art Zr-based films. The findings are highly relevant for industrial treatments of aluminium surfaces, especially for those that undergo corrosion protection and painting process steps prior to usage.

Interactions between structural and chemical biomimetism in synthetic stem cell niches

International Nuclear Information System (INIS)

Nava, Michele M; Raimondi, Manuela T; Credi, Caterina; De Marco, Carmela; Turri, Stefano; Cerullo, Giulio; Osellame, Roberto

2015-01-01

Advancements in understanding stem cell functions and differentiation are of key importance for the clinical success of stem-cell-based therapies. 3D structural niches fabricated by two-photon polymerization are a powerful platform for controlling stem cell growth and differentiation. In this paper, we investigate the possibility of further controlling stem cell fate by tuning the mechanical properties of such niches through coating with thin layers of biomimetic hyaluronan-based and gelatin-based hydrogels. We first assess the biocompatibility of chemical coatings and then study the interactions between structural and chemical biomimetism on the response of MSCs in terms of proliferation and differentiation. We observed a clear effect of the hydrogel coating on otherwise identical 3D scaffolds. In particular, in gelatin-coated niches we observed a stronger metabolic activity and commitment toward the osteo-chondral lineage with respect to hyaluronan-coated niches. Conversely, a reduction in the homing effect was observed in all the coated niches, especially in gelatin-coated niches. This study demonstrates the feasibility of controlling independently different mechanical cues, in bioengineered stem cell niches, i.e. the 3D scaffold geometry and the surface stiffness. This will allow, on the one hand, understanding their specific role in stem cell proliferation and differentiation and, on the other hand, finely tuning their synergistic effect. (paper)

Studies on conversion of crude sodium diuranate to high purity uranium oxide by chemical route

International Nuclear Information System (INIS)

Rajan, K.C.; Ramadevi, G.; Giri, Nitai; Chakravartty, J.K.; Sreenivas, T.

2016-01-01

Uranium values are recovered from ores and mine rejects by employing chemical processing methods. The process chemistry could be either acidic (H 2 SO 4 medium) or alkaline (Na 2 CO 3 - NaHCO 3 medium) based depending on the nature of host rock. The end product is termed as 'yellow cake' which is sent to refining plants for final purification and fuel manufacture. Conventionally the yellow cake product is magnesium (MDU) or ammonium diuranate (ADU) in U-plants following the acidic processing route while it is sodium diuranate (SDU) in the alkaline route. The preference for SDU in plants operating with alkaline route is mainly driven by the requirement of conserving and reusing the expensive chemicals. Though alkaline processing gives relatively purer diuranate product, the practice of direct precipitation of dissolved uranium from pregnant leach liquors invariably leads to presence of impurities detrimental for downstream unit operations, mostly in solvent extraction based refining stages. In this score uranium peroxide is superior to other uranates in many respects. Two alternatives are practiced for the conversion of SDU to uranium peroxide - chemical and fluid bed precipitation. Though generic flowsheet for the conversion stage is well documented, the process conditions and complexities vary with the chemistry of the pregnant leach liquor which is specific for a given ore or a deposit. This paper discusses the process scheme tailored, optimized and tested on a kilo-gram scale for chemical conversion of SDU produced by alkaline processing of a low-grade carbonate hosted uranium ore. The entire process scheme is first of its kind in Indian uranium ore processing arena

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.

On the tungsten single crystal coatings achieved by chemical vapor transportation deposition

Energy Technology Data Exchange (ETDEWEB)

Shi, J.Q.; Shen, Y.B.; Yao, S.Y.; Zhang, P.J.; Zhou, Q.; Guo, Y.Z. [School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081 (China); Tan, C.W., E-mail: tanchengwen@bit.edu.cn [School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081 (China); China Astronaut Research and Training Center, Beijing 100094 (China); Yu, X.D. [School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081 (China); China Astronaut Research and Training Center, Beijing 100094 (China); Nie, Z.H. [School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081 (China); Ma, H.L. [China Astronaut Research and Training Center, Beijing 100094 (China); Cai, H.N. [School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081 (China)

2016-12-15

The tungsten single crystal has many excellent properties, namely a high melting point, high anti-creeping strength. Chemical vapor transportation deposition (CVTD) is a possible approach to achieve large-sized W single crystals for high-temperature application such as the cathode of a thermionic energy converter. In this work, CVTD W coatings were deposited on the monocrystalline molybdenum substrate (a tube with < 111 > axial crystalline orientation) using WCl{sub 6} as a transport medium. The microstructures of the coatings were investigated by a scanning electron microscope (SEM) and electron backscatter diffraction (EBSD). The as-deposited coatings are hexagonal prisms—rough surfaces perpendicular to < 110 > with alternating hill-like bulges and pits at the side edges of the prisms, and flat surfaces perpendicular to < 112 > with arc-shaped terraces at the side faces. This can be explained by two-dimensional nucleation -mediated lateral growth model. Some parts of the coatings contain hillocks of an exotic morphology (noted as “abnormal growth”). The authors hypothesize that the abnormal growth is likely caused by the defects of the Mo substrate, which facilitate W nucleation sites, cause orientation difference, and may even form boundaries in the coatings. A dislocation density of 10{sup 6} to 10{sup 7} (counts/cm{sup 2}) was revealed by an etch-pit method and synchrotron X-ray diffraction. As the depositing temperature rises, the dislocation density decreases, and no sub-boundaries are found on samples deposited over 1300 °C, as a result of atom diffusion and dislocation climbing. - Highlights: •The varied growth rate causes the different morphologies of different planes. •The W coating is a single crystal when only single hillocks appear. •The (110) plane tends to have the lowest dislocation density. •The dislocation density tends to decrease as the temperature increases.

On the tungsten single crystal coatings achieved by chemical vapor transportation deposition

International Nuclear Information System (INIS)

Shi, J.Q.; Shen, Y.B.; Yao, S.Y.; Zhang, P.J.; Zhou, Q.; Guo, Y.Z.; Tan, C.W.; Yu, X.D.; Nie, Z.H.; Ma, H.L.; Cai, H.N.

2016-01-01

The tungsten single crystal has many excellent properties, namely a high melting point, high anti-creeping strength. Chemical vapor transportation deposition (CVTD) is a possible approach to achieve large-sized W single crystals for high-temperature application such as the cathode of a thermionic energy converter. In this work, CVTD W coatings were deposited on the monocrystalline molybdenum substrate (a tube with < 111 > axial crystalline orientation) using WCl 6 as a transport medium. The microstructures of the coatings were investigated by a scanning electron microscope (SEM) and electron backscatter diffraction (EBSD). The as-deposited coatings are hexagonal prisms—rough surfaces perpendicular to < 110 > with alternating hill-like bulges and pits at the side edges of the prisms, and flat surfaces perpendicular to < 112 > with arc-shaped terraces at the side faces. This can be explained by two-dimensional nucleation -mediated lateral growth model. Some parts of the coatings contain hillocks of an exotic morphology (noted as “abnormal growth”). The authors hypothesize that the abnormal growth is likely caused by the defects of the Mo substrate, which facilitate W nucleation sites, cause orientation difference, and may even form boundaries in the coatings. A dislocation density of 10 6 to 10 7 (counts/cm 2 ) was revealed by an etch-pit method and synchrotron X-ray diffraction. As the depositing temperature rises, the dislocation density decreases, and no sub-boundaries are found on samples deposited over 1300 °C, as a result of atom diffusion and dislocation climbing. - Highlights: •The varied growth rate causes the different morphologies of different planes. •The W coating is a single crystal when only single hillocks appear. •The (110) plane tends to have the lowest dislocation density. •The dislocation density tends to decrease as the temperature increases.

Chemical and Sensory Quality Preservation in Coated Almonds with the Addition of Antioxidants.

Science.gov (United States)

Larrauri, Mariana; Demaría, María Gimena; Ryan, Liliana C; Asensio, Claudia M; Grosso, Nelson R; Nepote, Valeria

2016-01-01

Almonds provide many benefits such as preventing heart disease due to their high content of oleic fatty acid-rich oil and other important nutrients. However, they are susceptible to oxidation reactions causing rancidity during storage. The objective of this work was to evaluate the chemical and sensory quality preservation of almonds coated with carboxymethyl cellulose and with the addition of natural and synthetic antioxidants during storage. Four samples were prepared: almonds without coating (C), almonds coated with carboxymethyl cellulose (CMC), almonds coated with CMC supplemented with peanut skins extract (E), and almonds coated with CMC and supplemented with butylhydroxytoluene (BHT). Proximate composition and fatty acid profile were determined on raw almonds. Almond samples (C, CMC, E and BHT) were stored at 40 °C for 126 d. Lipid oxidation indicators: peroxide value (PV), conjugated dienes (CD), volatile compounds (hexanal and nonanal), and sensory attributes were determined for the stored samples. Samples showed small but significant increases in PV, CD, hexanal and nonanal contents, and intensity ratings of negative sensory attributes (oxidized and cardboard). C had the highest tendency to deterioration during storage. At the end of storage (126 d), C had the highest PV (3.90 meqO2 /kg), and BHT had the lowest PV (2.00 meqO2 /kg). CMC and E samples had similar intermediate PV values (2.69 and 2.57 meqO2 /kg, respectively). CMC coating and the addition of natural (peanut skin extract) and synthetic (BHT) antioxidants provide protection to the roasted almond product. © 2015 Institute of Food Technologists®

Protective Coatings for Wet Storage of Aluminium-Clad Spent Fuel

Energy Technology Data Exchange (ETDEWEB)

Fernandes, S.M.C.; Correa, O.V.; Souza, J.A. De; Ramanathan, L.V. [Materials science and Technology Center, Instituto de Pesquisas Energeticas e Nucleares - IPEN, Av. Prof. Lineu Prestes 2242, Cidade Universitaria, 05508-000 Sao Paulo (Brazil)

2011-07-01

Corrosion protection of spent RR fuel for long term wet storage was considered important, primarily from the safety standpoint and the use of conversion coatings was proposed in 2008. This paper presents the results of: (a) on-going field tests in which un-coated and lanthanide-based conversion coated Al alloy coupons were exposed to the IEA-R1 reactor spent fuel basin for durations of up to a year; (b) preparation of cerium modified hydrotalcite coatings and cerium sealed boehmite coatings on AA 6061 alloy; (c) corrosion resistance of coated specimens in NaCl solutions. The field studies indicated that the oxidized and cerium dioxide coated coupons were the most corrosion resistant. The cerium modified hydrotalcite and cerium sealed boehmite coated specimens showed marked increase in pitting corrosion resistance. (author)

Evaluation of corrosion behaviour of tantalum coating obtained by low pressure chemical vapor deposition using electrochemical polarization

Science.gov (United States)

Levesque, A.; Bouteville, A.; de Baynast, H.; Laveissière, B.

2002-06-01

antalum coatings are elaborated on titanium substrates through Low Pressure Chemical Vapor Deposition from tantalum pentachloride-hydrogen gaseous phase at a deposition temperature of 800 °C and a total pressure of 3.3 mbar. The aim of this paper is to evaluate the effectiveness of this tantalum coating in corrosive solution. Optical Microscopy and Scanning Electron Microscopy observations reveal that deposits are of 1.7 μm in thickness and conformal. The corrosion resistance of tantalum coated titanium substrates is quantified through standard potentiodynamic polarization method. Even for tantalum coatings exhibiting some defects as pores, the corrosion current density is as low as 0.25 mA/cm^2.in very agressive solutions like kroll reagent (HN03/HF).

In situ spray deposition of cell-loaded, thermally and chemically gelling hydrogel coatings for tissue regeneration.

Science.gov (United States)

Pehlivaner Kara, Meryem O; Ekenseair, Adam K

2016-10-01

In this study, the efficacy of creating cellular hydrogel coatings on warm tissue surfaces through the minimally invasive, sprayable delivery of thermoresponsive liquid solutions was investigated. Poly(N-isopropylacrylamide)-based (pNiPAAm) thermogelling macromers with or without addition of crosslinking polyamidoamine (PAMAM) macromers were synthesized and used to produce in situ forming thermally and chemically gelling hydrogel systems. The effect of solution and process parameters on hydrogel physical properties and morphology was evaluated and compared to poly(ethylene glycol) and injection controls. Smooth, fast, and conformal hydrogel coatings were obtained when pNiPAAm thermogelling macromers were sprayed with high PAMAM concentration at low pressure. Cellular hydrogel coatings were further fabricated by different spraying techniques: single-stream, layer-by-layer, and dual stream methods. The impact of spray technique, solution formulation, pressure, and spray solution viscosity on the viability of fibroblast and osteoblast cells encapsulated in hydrogels was elucidated. In particular, the early formation of chemically crosslinked micronetworks during bulk liquid flow was shown to significantly affect cell viability under turbulent conditions compared to injectable controls. The results demonstrated that sprayable, in situ forming hydrogels capable of delivering cell populations in a homogeneous therapeutic coating on diseased tissue surfaces offer promise as novel therapies for applications in regenerative medicine. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2383-2393, 2016. © 2016 Wiley Periodicals, Inc.

A Two-Level Undercut-Profile Substrate for Chemical-Solution-Based Filamentary Coated Conductors

DEFF Research Database (Denmark)

Wulff, Anders Christian; Lundeman, Jesper H.; Hansen, Jørn B.

2016-01-01

. In the present study, the 2LUPS concept is applied to a commercial cube-textured Ni-5at.% W tape, and the surface of the 2LUPS coated with two Gd2Zr2O7 buffer layers using chemical solution deposition is examined. Except for narrow regions near the edge of upper plateaus, the plateaus are found to be covered...

Corrosion resistance of multilayered magnesium phosphate/magnesium hydroxide film formed on magnesium alloy using steam-curing assisted chemical conversion method

International Nuclear Information System (INIS)

Ishizaki, Takahiro; Kudo, Ruriko; Omi, Takeshi; Teshima, Katsuya; Sonoda, Tsutomu; Shigematsu, Ichinori; Sakamoto, Michiru

2012-01-01

Anticorrosive multilayered films were successfully prepared on magnesium alloy AZ31 by chemical conversion treatment, followed by steam curing treatment. The crystal structures, chemical composition, surface morphologies, chemical bonding states of the film was characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and field emission scanning electron microscope (FE-SEM) measurements. All the films had thicknesses of ranging from 24 to 32 μm. The film had two layers that were composed of crystalline NH 4 MgPO 4 ·H 2 O, Mg 2 PO 4 OH·3H 2 O, Mg(OH) 2 and amorphous MgO. The outer layers include magnesium, oxygen, and phosphorous, and the inner layers include magnesium and oxygen. The corrosion resistant performances of the multilayered films in 5 wt% NaCl aqueous solution were investigated by electrochemical and gravimetric measurements. The potentiodynamic polarization curves revealed that the corrosion current density (j corr ) of all the film coated magnesium alloys decreased by more than four orders of magnitude as compared to that of the bare magnesium alloy, indicating that all the films had an inhibiting effect of corrosion reaction. Gravimetric measurements showed that the average corrosion rates obtained from the weight loss rates were estimated to be in the ranges of ca. 0.085–0.129 mm/y. American Society for Testing and Materials (ASTM) standard D 3359-02 cross cut tape test revealed that the adhesion of our anticorrosive multilayered film to the magnesium alloy surface was very good.

Chemical stability of fluorine-containing coatings of cold drying for radiation - protection technique articles

International Nuclear Information System (INIS)

Shigorina, I.I.; Zvyagintseva, N.V.; Egorov, B.N.

1977-01-01

The chemical stability of fluorolon coatings, which are not subjected to heat treatment or hot drying during application, has been studied. The test for layer life-time has been performed by submerging specimens in agressive medium. The time for one upper removable layer to fail under steady action of agressive liquid is found to be: > 12 months at 20 deg C, 6-9 months at 40 deg C; at 60 deg C the time of layer stability depends upon medium: 1 month for nitric, 2 months for acetic, 2-3 months for sulphuric and hydrochloric acid. The coatings are recommended for practical application in radiation-protective technique

Coated particle waste form development

International Nuclear Information System (INIS)

Oma, K.H.; Buckwalter, C.Q.; Chick, L.A.

1981-12-01

Coated particle waste forms have been developed as part of the multibarrier concept at Pacific Northwest Laboratory under the Alternative Waste Forms Program for the Department of Energy. Primary efforts were to coat simulated nuclear waste glass marbles and ceramic pellets with low-temperature pyrolytic carbon (LT-PyC) coatings via the process of chemical vapor deposition (CVD). Fluidized bed (FB) coaters, screw agitated coaters (SAC), and rotating tube coaters were used. Coating temperatures were reduced by using catalysts and plasma activation. In general, the LT-PyC coatings did not provide the expected high leach resistance as previously measured for carbon alone. The coatings were friable and often spalled off the substrate. A totally different concept, thermal spray coating, was investigated at PNL as an alternative to CVD coating. Flame spray, wire gun, and plasma gun systems were evaluated using glass, ceramic, and metallic coating materials. Metal plasma spray coatings (Al, Sn, Zn, Pb) provided a two to three orders-of-magnitude increase in chemical durability. Because the aluminum coatings were porous, the superior leach resistance must be due to either a chemical interaction or to a pH buffer effect. Because they are complex, coated waste form processes rank low in process feasibility. Of all the possible coated particle processes, plasma sprayed marbles have the best rating. Carbon coating of pellets by CVD ranked ninth when compared with ten other processes. The plasma-spray-coated marble process ranked sixth out of eleven processes

Superconducting magnesium diboride coatings for radio frequency cavities fabricated by hybrid physical-chemical vapor deposition

Science.gov (United States)

Wolak, M. A.; Tan, T.; Krick, A.; Johnson, E.; Hambe, M.; Chen, Ke; Xi, X. X.

2014-01-01

We have investigated the coating of an inner surface of superconducting radio frequency cavities with a magnesium diboride thin film by hybrid physical-chemical vapor deposition (HPCVD). To simulate a 6 GHz rf cavity, a straight stainless steel tube of 1.5-inch inner diameter and a dummy stainless steel cavity were employed, on which small sapphire and metal substrates were mounted at different locations. The MgB2 films on these substrates showed uniformly good superconducting properties including Tc of 37-40 K, residual resistivity ratio of up to 14, and root-mean-square roughness Rq of 20-30 nm. This work demonstrates the feasibility of coating the interior of cylindrical and curved objects with MgB2 by the HPCVD technique, an important step towards superconducting rf cavities with MgB2 coating.

The adhesion performance of epoxy coating on AA6063 treated in Ti/Zr/V based solution

Science.gov (United States)

Zhu, Wen; Li, Wenfang; Mu, Songlin; Yang, Yunyu; Zuo, Xi

2016-10-01

An environment-friendly titanium/zirconium/vanadium-based (Ti/Zr/V) conversion coating was prepared on aluminum alloy 6063 (AA6063). The epoxy powder coatings were applied on the AA6063 samples with/without Ti/Zr/V conversion coatings via electrostatic spraying. The morphology and composition of the conversion coating were studied by scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS), respectively. The surface free energy components of AA6063 samples were measured by a static contact angle measuring device with Owens method. The adhesion properties of the epoxy coating on AA6063 treated with different conversion times were evaluated using a pull-off tester. The Ti/Zr/V conversion coating was mainly composed of metal oxide (TiO2, ZrO2, V2O5, Al2O3, etc.), metal fluoride (ZrF4, AlF3, etc.) and metal organic complex. The formation time of this conversion coating was reduced to 50 s. After such surface treatment, the samples' surface roughness was increased and the contact angle with water was decreased. Both the surface free energy and the work of adhesion were increased. The adhesion strength between the epoxy coating and AA6063 was enhanced significantly.

Lignite chemical conversion in an indirect heat rotary kiln gasifier

Directory of Open Access Journals (Sweden)

Hatzilyberis Kostas S.

2006-01-01

Full Text Available The results on the gasification of Greek lignite using two indirect heat (allothermal pilot rotary kiln gasifiers are reported in the present work. The development of this new reactor-gasifier concept intended for solid fuels chemical conversion exploits data and experience gained from the following two pilot plants. The first unit A (about 100 kg/h raw lignite demonstrated the production of a medium heating value gas (12-13 MJ/Nm3 with quite high DAF (dry ash free coal conversions, in an indirect heat rotary gasifier under mild temperature and pressure conditions. The second unit B is a small pilot size unit (about 10 kg/h raw lignite comprises an electrically heated rotary kiln, is an operation flexible and exhibits effective phase mixing and enhanced heat transfer characteristics. Greek lignite pyrolysis and gasification data were produced from experiments performed with pilot plant B and the results are compared with those of a theoretical model. The model assumes a scheme of three consecutive-partly parallel processes (i. e. drying, pyrolysis, and gasification and predicts DAF lignite conversion and gas composition in relatively good agreement with the pertinent experimental data typical of the rotary kiln gasifier performance. Pilot plant B is currently being employed in lime-enhanced gasification studies aiming at the production of hydrogen enriched synthesis gas. Presented herein are two typical gas compositions obtain from lignite gasification runs in the presence or not of lime. .

Ternary cobalt-molybdenum-zirconium coatings for alternative energies

Science.gov (United States)

Yar-Mukhamedova, Gulmira; Ved', Maryna; Sakhnenko, Nikolay; Koziar, Maryna

2017-11-01

Consistent patterns for electrodeposition of Co-Mo-Zr coatings from polyligand citrate-pyrophosphate bath were investigated. The effect of both current density amplitude and pulse on/off time on the quality, composition and surface morphology of the galvanic alloys were determined. It was established the coating Co-Mo-Zr enrichment by molybdenum with current density increasing up to 8 A dm-2 as well as the rising of pulse time and pause duration promotes the content of molybdenum because of subsequent chemical reduction of its intermediate oxides by hydrogen ad-atoms. It was found that the content of the alloying metals in the coating Co-Mo-Zr depends on the current density and on/off times extremely and maximum Mo and Zr content corresponds to the current density interval 4-6 A dm-2, on-/off-time 2-10 ms. Chemical resistance of binary and ternary coatings based on cobalt is caused by the increased tendency to passivity and high resistance to pitting corrosion in the presence of molybdenum and zirconium, as well as the acid nature of their oxides. Binary coating with molybdenum content not less than 20 at.% and ternary ones with zirconium content in terms of corrosion deep index are in a group ;very proof;. It was shown that Co-Mo-Zr alloys exhibits the greatest level of catalytic properties as cathode material for hydrogen electrolytic production from acidic media which is not inferior a platinum electrode. The deposits Co-Mo-Zr with zirconium content 2-4 at.% demonstrate high catalytic properties in the carbon(II) oxide conversion. This confirms the efficiency of materials as catalysts for the gaseous wastes purification and gives the reason to recommend them as catalysts for red-ox processes activating by oxygen as well as electrode materials for red-ox batteries.

Employment of an ion implantation technique for catalyst coating on various substrates

International Nuclear Information System (INIS)

Bannikov, M.G.; Chattha, J.A.; Zlobin, V.N.; Vasilve, I.P.; Cherkasov, J.A.; Gawrilenko, P.N.

2001-01-01

Catalysts are widely used in the chemical industry as well as in the production of vehicle catalytic converters. Precious metals are employed increasingly as catalytic materials. Traditional methods of coating, such as impregnation, are thought to reduce the porosity and specific area of catalyst thus reducing the catalytic efficiency. Apart from that, impregnation technology leads to the high expense of precious metals. To reduce the content of noble metals in catalysts the ion implantation method of coating has been investigated. Several samples of catalysts on various substrates were prepared by ion implantation technique and tested. New catalysts have shown high nitric oxides (NO/sub x/) and carbon monoxide (CO) conversion efficiency, with the content of noble metals reduced substantially. Experiment has also shown that specific area of substrates coated by an ion implantation had not decreased. Schematic of an ion implanter and experimental results are provided. (author)

The formation of FHA coating on biodegradable Mg-Zn-Zr alloy using a two-step chemical treatment method

International Nuclear Information System (INIS)

Jiang, S.T.; Zhang, J.; Shun, S.Z.; Chen, M.F.

2016-01-01

Highlights: • Use a two-step chemical treatment method for formation of FHA coating on biodegradable Mg-Zn-Zr alloy;. • We reported the formation mechanism of FHA coating on Mg-Zn-Zr alloy and achieved optimum properties;. • The MgF_2 coating and FHA coating provide effective protection for the Mg alloy substrate and the FHA coating showed better corrosion resistance. - Abstract: To improve the corrosion resistance of the biomedical magnesium alloy, a two-step chemical treatment method has been employed to prepare an FHA coating on the alloy surface. Prior to forming an FHA layer, the samples of Mg-3 wt% Zn-0.5 wt% Zr alloy were soaked in HF with concentration of 20% (v/v) at 37 °C temperature for 2 h, and were then placed into an aqueous solution with 0.1 mol/L Ca(NO_3).4H_2O and 0.06 mol/L NH_4H_2PO_4 at 90 °C to prepare the Ca-P coating. The concentrations of Mg"2"+, F"− ions, and pH variation with immersing time in the solution were investigated to explore the growth mechanism of FHA. The surface morphologies and compositions of the coatings were characterized by X-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy. The results showed that the alloy surface treated with acid formed a layer of MgF_2 nanoparticles with a thickness of 0.7 μm. The corrosion resistance of coatings in SBF solution was evaluated by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization. The results showed that the substrate with FHA coating had good corrosion resistance. After immersing into the calcium phosphate solution, some small spherical particles were first formed on the surface; these then cover the surface completely after 20 min. Some clusters consisting of needle-like crystal were observed in the spherical particles covering the surface, and the Ca/P ratio of the needle-like crystal was 1.46, clearly growing along the c axis preferred orientation growth. After immersion for 60 min, the FHA coating with

Evaluation of a Low Temperature Cure Powder Coating

Science.gov (United States)

2008-05-01

4”x6”x1/4” Al 2024-T3 panels were chromate conversion coated by NDCEE per MIL-DTL-5514F Type 1 Class A  Reserved for LTCPC  27 – 4”x6”x1/4” Al...2024-T3 panels were chromate conversion coated by FRC Southeast per MIL-DTL- 5514F Type 1 Class A  Reserved for baseline coating JSEM - May...conducted under contract W74V8H- 04-D-0005 Task 427. DISCLAIMER: The contents of this document are not to be used for advertising , publication, or

Erythrocyte membrane-coated gold nanocages for targeted photothermal and chemical cancer therapy

Science.gov (United States)

Zhu, Dao-Ming; Xie, Wei; Xiao, Yu-Sha; Suo, Meng; Zan, Ming-Hui; Liao, Qing-Quan; Hu, Xue-Jia; Chen, Li-Ben; Chen, Bei; Wu, Wen-Tao; Ji, Li-Wei; Huang, Hui-Ming; Guo, Shi-Shang; Zhao, Xing-Zhong; Liu, Quan-Yan; Liu, Wei

2018-02-01

Recently, red blood cell (RBC) membrane-coated nanoparticles have attracted much attention because of their excellent immune escapability; meanwhile, gold nanocages (AuNs) have been extensively used for cancer therapy due to their photothermal effect and drug delivery capability. The combination of the RBC membrane coating and AuNs may provide an effective approach for targeted cancer therapy. However, few reports have shown the utilization of combining these two technologies. Here, we design erythrocyte membrane-coated gold nanocages for targeted photothermal and chemical cancer therapy. First, anti-EpCam antibodies were used to modify the RBC membranes to target 4T1 cancer cells. Second, the antitumor drug paclitaxel (PTX) was encapsulated into AuNs. Then, the AuNs were coated with the modified RBC membranes. These new nanoparticles were termed EpCam-RPAuNs. We characterized the capability of the EpCam-RPAuNs for selective tumor targeting via exposure to near-infrared irradiation. The experimental results demonstrate that EpCam-RPAuNs can effectively generate hyperthermia and precisely deliver the antitumor drug PTX to targeted cells. We also validated the biocompatibility of the EpCam-RAuNs in vitro. By combining the molecularly modified targeting RBC membrane and AuNs, our approach provides a new way to design biomimetic nanoparticles to enhance the surface functionality of nanoparticles. We believe that EpCam-RPAuNs can be potentially applied for cancer diagnoses and therapies.

Functional coatings: the sol-gel approach

International Nuclear Information System (INIS)

Belleville, Ph.

2010-01-01

CEA's sol-gel laboratory is specialized in the development of innovative sol-gel optical coatings and has extended its application field to membrane materials and coatings for energy conversion, to electric coatings for microelectronics devices and to thin films for gas sensing. This article describes, by way of examples, the laboratory's research on sol-gel functional coatings, including nano-material synthesis, organic-inorganic hybrid-based solution preparation as well as deposition process development and prototyping. (author)

Less-Toxic Coatings for Inhibiting Corrosion of Aluminum

Science.gov (United States)

Minevski, Zoran; Clarke, Eric; Eylem, Cahit; Maxey, Jason; Nelson, Carl

2003-01-01

Two recently invented families of conversion- coating processes have been found to be effective in reducing or preventing corrosion of aluminum alloys. These processes offer less-toxic alternatives to prior conversion-coating processes that are highly effective but have fallen out of favor because they generate chromate wastes, which are toxic and carcinogenic. Specimens subjected to these processes were found to perform well in standard salt-fog corrosion tests.

Surface-dependent chemical equilibrium constants and capacitances for bare and 3-cyanopropyldimethylchlorosilane coated silica nanochannels.

Science.gov (United States)

Andersen, Mathias Bækbo; Frey, Jared; Pennathur, Sumita; Bruus, Henrik

2011-01-01

We present a combined theoretical and experimental analysis of the solid-liquid interface of fused-silica nanofabricated channels with and without a hydrophilic 3-cyanopropyldimethylchlorosilane (cyanosilane) coating. We develop a model that relaxes the assumption that the surface parameters C(1), C(2), and pK(+) are constant and independent of surface composition. Our theoretical model consists of three parts: (i) a chemical equilibrium model of the bare or coated wall, (ii) a chemical equilibrium model of the buffered bulk electrolyte, and (iii) a self-consistent Gouy-Chapman-Stern triple-layer model of the electrochemical double layer coupling these two equilibrium models. To validate our model, we used both pH-sensitive dye-based capillary filling experiments as well as electro-osmotic current-monitoring measurements. Using our model we predict the dependence of ζ potential, surface charge density, and capillary filling length ratio on ionic strength for different surface compositions, which can be difficult to achieve otherwise. Copyright © 2010 Elsevier Inc. All rights reserved.

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

International Nuclear Information System (INIS)

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

2013-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2013-07-01

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

Separation of Corn Fiber and Conversion to Fuels and Chemicals Phase II: Pilot-scale Operation

Energy Technology Data Exchange (ETDEWEB)

Abbas, Charles; Beery, Kyle; Orth, Rick; Zacher, Alan

2007-09-28

The purpose of the Department of Energy (DOE)-supported corn fiber conversion project, “Separation of Corn Fiber and Conversion to Fuels and Chemicals Phase II: Pilot-scale Operation” is to develop and demonstrate an integrated, economical process for the separation of corn fiber into its principal components to produce higher value-added fuel (ethanol and biodiesel), nutraceuticals (phytosterols), chemicals (polyols), and animal feed (corn fiber molasses). This project has successfully demonstrated the corn fiber conversion process on the pilot scale, and ensured that the process will integrate well into existing ADM corn wet-mills. This process involves hydrolyzing the corn fiber to solubilize 50% of the corn fiber as oligosaccharides and soluble protein. The solubilized fiber is removed and the remaining fiber residue is solvent extracted to remove the corn fiber oil, which contains valuable phytosterols. The extracted oil is refined to separate the phytosterols and the remaining oil is converted to biodiesel. The de-oiled fiber is enzymatically hydrolyzed and remixed with the soluble oligosaccharides in a fermentation vessel where it is fermented by a recombinant yeast, which is capable of fermenting the glucose and xylose to produce ethanol. The fermentation broth is distilled to remove the ethanol. The stillage is centrifuged to separate the yeast cell mass from the soluble components. The yeast cell mass is sold as a high-protein yeast cream and the remaining sugars in the stillage can be purified to produce a feedstock for catalytic conversion of the sugars to polyols (mainly ethylene glycol and propylene glycol) if desirable. The remaining materials from the purification step and any materials remaining after catalytic conversion are concentrated and sold as a corn fiber molasses. Additional high-value products are being investigated for the use of the corn fiber as a dietary fiber sources.

Hexavalent Chromium Free Coatings Projects for Aerospace Applications

Science.gov (United States)

2012-08-01

laboratory qualification of a total hexavalent chrome free coating systems for use on magnesium transmission housings. This project will leverage... hexavalent chrome free coating system by utilizing a hexavalent chrome free topcoat, primer, and pretreatment for magnesium parts used on Army...of the hexavalent chrome free conversion coatings. Hexavalent Chromium Free Coating System for Magnesium Housings on Aviation Systems Desert

Characteristics and corrosion studies of vanadate conversion coating formed on Mg-14 wt%Li-1 wt%Al-0.1 wt%Ce alloy

Energy Technology Data Exchange (ETDEWEB)

Ma Yibin [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); Li Ning, E-mail: lininghit@263.net [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); Li Deyu [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); Zhang Milin; Huang Xiaomei [Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, Harbin Engineering University, Harbin 150001 (China)

2012-11-15

Highlights: Black-Right-Pointing-Pointer Vanadate film forms on the surface of Mg-Li-Al-Ce alloy. Black-Right-Pointing-Pointer Vanadate coating improves the corrosion resistance. Black-Right-Pointing-Pointer Vanadate coating is composed of Mg(OH){sub 2}, Li{sub 2}O and V{sub 2}O{sub 5}. - Abstract: Mg-14Li-1Al-0.1Ce alloy is immersed in NH{sub 4}VO{sub 3} + K{sub 3}(Fe(CN){sub 6}) solutions with different NH{sub 4}VO{sub 3} and/or K{sub 3}(Fe(CN){sub 6}) concentrations, and different immersion time. The surface morphology and composition of the vanadate coating are then characterized by scanning electron microscopy with energy dispersion spectroscopy (SEM-EDS) and X-ray photoelectron spectroscopy (XPS), and the corrosion behavior of the conversion coating is studied by polarization technique and electrochemical impedance spectroscopy (EIS). The experimental results indicate that the vanadate film with better corrosion resistance forms on Mg-Li-Al-Ce surface after the sample is immersed in 30 g L{sup -1} NH{sub 4}VO{sub 3} + 3.75 g L{sup -1} K{sub 3}(Fe(CN){sub 6}) solution at 80 Degree-Sign C for 10 min. The coating consists of V{sub 2}O{sub 5}, Li{sub 2}O and Mg(OH){sub 2}.

Development of Diffusion barrier coatings and Deposition Technologies for Mitigating Fuel Cladding Chemical Interactions (FCCI)

Energy Technology Data Exchange (ETDEWEB)

Sridharan, Kumar; Allen, Todd; Cole, James

2013-02-27

The goal of this project is to develop diffusion barrier coatings on the inner cladding surface to mitigate fuel-cladding chemical interaction (FCCI). FCCI occurs due to thermal and radiation enhanced inter-diffusion between the cladding and fuel materials, and can have the detrimental effects of reducing the effective cladding wall thickness and lowering the melting points of the fuel and cladding. The research is aimed at the Advanced Burner Reactor (ABR), a sodium-cooled fast reactor, in which higher burn-ups will exacerbate the FCCI problem. This project will study both diffusion barrier coating materials and deposition technologies. Researchers will investigate pure vanadium, zirconium, and titanium metals, along with their respective oxides, on substrates of HT-9, T91, and oxide dispersion-strengthened (ODS) steels; these materials are leading candidates for ABR fuel cladding. To test the efficacy of the coating materials, the research team will perform high-temperature diffusion couple studies using both a prototypic metallic uranium fuel and a surrogate the rare-earth element lanthanum. Ion irradiation experiments will test the stability of the coating and the coating-cladding interface. A critical technological challenge is the ability to deposit uniform coatings on the inner surface of cladding. The team will develop a promising non-line-of-sight approach that uses nanofluids . Recent research has shown the feasibility of this simple yet novel approach to deposit coatings on test flats and inside small sections of claddings. Two approaches will be investigated: 1) modified electrophoretic deposition (MEPD) and 2) boiling nanofluids. The coatings will be evaluated in the as-deposited condition and after sintering.

Chemical vapour deposition at atmospheric pressure of graphene on molybdenum foil: Effect of annealing time on characteristics and corrosion stability of graphene coatings

International Nuclear Information System (INIS)

Naghdi, Samira; Jevremović, Ivana; Mišković-Stanković, Vesna; Rhee, Kyong Yop

2016-01-01

Highlights: • Atmospheric pressure chemical vapor deposition of graphene on molybdenum foils. • Quality and domain size of graphene layers increased with longer annealing times. • The number of graphene layers decreased with longer annealing times. • Graphene coatings on molybdenum foils exhibited corrosion inhibitive properties. - Abstract: In this work, the effect of pre-annealing of Mo substrate on the quality of graphene layers grown by chemical vapour deposition was investigated by X-ray diffraction, X-ray photoelectron spectroscopy, and Raman spectroscopy. Moreover, different electrochemical techniques were employed to investigate the corrosion stability of the graphene coated Mo in 0.1 M NaCl. Longer annealing time resulted in less defective graphene coatings with fewer layers. Graphene coating on the annealed Mo provided better protection against corrosion during the initial exposure times, while after prolonged exposure times, both graphene coatings on annealed and non-annealed Mo exhibited nearly the same corrosion inhibitive properties.

Superconducting magnesium diboride coatings for radio frequency cavities fabricated by hybrid physical-chemical vapor deposition

Directory of Open Access Journals (Sweden)

M. A. Wolak

2014-01-01

Full Text Available We have investigated the coating of an inner surface of superconducting radio frequency cavities with a magnesium diboride thin film by hybrid physical-chemical vapor deposition (HPCVD. To simulate a 6 GHz rf cavity, a straight stainless steel tube of 1.5-inch inner diameter and a dummy stainless steel cavity were employed, on which small sapphire and metal substrates were mounted at different locations. The MgB_{2} films on these substrates showed uniformly good superconducting properties including T_{c} of 37–40 K, residual resistivity ratio of up to 14, and root-mean-square roughness R_{q} of 20–30 nm. This work demonstrates the feasibility of coating the interior of cylindrical and curved objects with MgB_{2} by the HPCVD technique, an important step towards superconducting rf cavities with MgB_{2} coating.

Doctor Blade-Coated Polymer Solar Cells

KAUST Repository

Cho, Nam Chul

2016-10-25

In this work, we report polymer solar cells based on blade-coated P3HT:PC71BM and PBDTTT-EFT:PC71BM bulk heterojunction photoactive layers. Enhanced power conversion efficiency of 2.75 (conventional structure) and 3.03% (inverted structure) with improved reproducibility was obtained from blade-coated P3HT:PC71BM solar cells, compared to spin-coated ones. Furthermore, by demonstrating 3.10% efficiency flexible solar cells using blade-coated PBDTTT-EFT:PC71BM films on the plastic substrates, we suggest the potential applicability of blade coating technique to the high throughput roll-to-roll fabrication systems.

PROCESSES PROCEEDING ON CONCRETE COATING SURFACES IN CASE OF THEIR CHEMICAL PROTECTION AGAINST WINTER SLIPPERINESS

Directory of Open Access Journals (Sweden)

M. K. Pshembaev

2016-01-01

Full Text Available Concrete coatings of road traffic highways along with operational loadings caused by flow of traffic are subjected to weather and climate impacts. These are the following impacts: changes in temperature and air humidity, solar radiation,surface wind speed which is participating in formation of active heat-and-mass transfer in a surface layer of the concrete coating. One of the most complicated and important periods in the road traffic highway operation is so called transitional nature period (from Summer to Autumn and from Winter to Spring. These periods are accompanied by intensive rain and snow fall and possible formation of ice loading on the surface of cement and concrete coatings. These impacts significantly deteriorate friction properties of road pavement (friction factor φ is decreased up to 0.4 and less that can be a prerequisite to creation of various accident situations due to sharp increase in braking distance. For example, while having dry pavement the friction factor φ is equal to 0.80–0.85, and during icy condition of the road the factor φ constitutes 0.08–0.15 that consequently entails an increase in braking distance from 7.5 up to 20.0 m and more. It is quite possible that ice layer appears on the surface of concrete coatings when road traffic highways are used in winter season. Various methods are applicable to remove ice from the surface they can include also ice-melting chemicals and sodium chloride NaCl in particular. The chemical decreases freezing temperature of the formed brine and causes ice melting at negative temperature. Processes of NaCl dissolution and ice melting have an endothermic character, in other words these processes are accompanied by heat ingress and due to it temperature is sharply decreasing in the surface layer of the concrete coating which is under the melting ice and in this case phenomenon of thermal shock is observed.

Uranium conversion

International Nuclear Information System (INIS)

Oliver, Lena; Peterson, Jenny; Wilhelmsen, Katarina

2006-03-01

FOI, has performed a study on uranium conversion processes that are of importance in the production of different uranium compounds in the nuclear industry. The same conversion processes are of interest both when production of nuclear fuel and production of fissile material for nuclear weapons are considered. Countries that have nuclear weapons ambitions, with the intention to produce highly enriched uranium for weapons purposes, need some degree of uranium conversion capability depending on the uranium feed material available. This report describes the processes that are needed from uranium mining and milling to the different conversion processes for converting uranium ore concentrate to uranium hexafluoride. Uranium hexafluoride is the uranium compound used in most enrichment facilities. The processes needed to produce uranium dioxide for use in nuclear fuel and the processes needed to convert different uranium compounds to uranium metal - the form of uranium that is used in a nuclear weapon - are also presented. The production of uranium ore concentrate from uranium ore is included since uranium ore concentrate is the feed material required for a uranium conversion facility. Both the chemistry and principles or the different uranium conversion processes and the equipment needed in the processes are described. Since most of the equipment that is used in a uranium conversion facility is similar to that used in conventional chemical industry, it is difficult to determine if certain equipment is considered for uranium conversion or not. However, the chemical conversion processes where UF 6 and UF 4 are present require equipment that is made of corrosion resistant material

Implementing New Non-Chromate Coatings Systems (Briefing Charts)

Science.gov (United States)

2011-02-09

Initiate Cr6+ authorization process for continued Cr6+ use using the form, Authorization to Use Hexavalent Chromium. YES NO • Approval of...Aluminum and magnesium anodizing • Hard Chrome Plating • Type II conversion coating on aluminum alloys under chromated primer • Type II conversion coating...Elimination of Hexavalent Chromium 80% 5% 14% 1% Type II Type III Type IC Type IC Fatigue Critical 50% 50% Type II Type IC FRC-SE (JAX) Fully Integrated FRC

The formation of FHA coating on biodegradable Mg-Zn-Zr alloy using a two-step chemical treatment method

Energy Technology Data Exchange (ETDEWEB)

Jiang, S.T.; Zhang, J.; Shun, S.Z. [School of Materials Science and Engineering, Tianjin University of Technology, Tianjin (China); Chen, M.F., E-mail: mfchentj@126.com [School of Materials Science and Engineering, Tianjin University of Technology, Tianjin (China); Tianjin Key Laboratory of Display Materials and Photoelectric Device, Tianjin University of Technology , Tianjin (China)

2016-12-01

Highlights: • Use a two-step chemical treatment method for formation of FHA coating on biodegradable Mg-Zn-Zr alloy;. • We reported the formation mechanism of FHA coating on Mg-Zn-Zr alloy and achieved optimum properties;. • The MgF{sub 2} coating and FHA coating provide effective protection for the Mg alloy substrate and the FHA coating showed better corrosion resistance. - Abstract: To improve the corrosion resistance of the biomedical magnesium alloy, a two-step chemical treatment method has been employed to prepare an FHA coating on the alloy surface. Prior to forming an FHA layer, the samples of Mg-3 wt% Zn-0.5 wt% Zr alloy were soaked in HF with concentration of 20% (v/v) at 37 °C temperature for 2 h, and were then placed into an aqueous solution with 0.1 mol/L Ca(NO{sub 3}).4H{sub 2}O and 0.06 mol/L NH{sub 4}H{sub 2}PO{sub 4} at 90 °C to prepare the Ca-P coating. The concentrations of Mg{sup 2+}, F{sup −} ions, and pH variation with immersing time in the solution were investigated to explore the growth mechanism of FHA. The surface morphologies and compositions of the coatings were characterized by X-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy. The results showed that the alloy surface treated with acid formed a layer of MgF{sub 2} nanoparticles with a thickness of 0.7 μm. The corrosion resistance of coatings in SBF solution was evaluated by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization. The results showed that the substrate with FHA coating had good corrosion resistance. After immersing into the calcium phosphate solution, some small spherical particles were first formed on the surface; these then cover the surface completely after 20 min. Some clusters consisting of needle-like crystal were observed in the spherical particles covering the surface, and the Ca/P ratio of the needle-like crystal was 1.46, clearly growing along the c axis preferred orientation growth. After

Dry Sintered Metal Coating of Halloysite Nanotubes

Directory of Open Access Journals (Sweden)

James C. Nicholson

2016-09-01

Full Text Available Halloysite nanotubes (HNTs are a naturally-occurring aluminosilicate whose dimensions measure microns in length and tens of nanometers in diameter. Bonding defects between the alumina and silica lead to net negative and positive charges on the exterior and interior lumen, respectively. HNTs have been shown to enhance the material properties of polymer matrices and enable the sustained release of loaded chemicals, drugs, and growth factors. Due to the net charges, these nanotubes can also be readily coated in layered-depositions using the HNT exterior lumen’s net negative charge as the basis for assembly. These coatings are primarily done through wet chemical processes, the majority of which are limited in their use of desired chemicals, due to the polarity of the halloysite. Furthermore, this restriction in the type of chemicals used often requires the use of more toxic chemicals in place of greener options, and typically necessitates the use of a significantly longer chemical process to achieve the desired coating. In this study, we show that HNTs can be coated with metal acetylacetonates—compounds primarily employed in the synthesis of nanoparticles, as metal catalysts, and as NMR shift reagents—through a dry sintering process. This method was capable of thermally decaying the metal acetylacetonate, resulting in a free positively-charged metal ion that readily bonded to the negatively-charged HNT exterior, resulting in metallic coatings forming on the HNT surface. Our coating method may enable greater deposition of coated material onto these nanotubes as required for a desired application. Furthermore, the use of chemical processes using toxic chemicals is not required, thus eliminating exposure to toxic chemicals and costs associated with the disposal of the resultant chemical waste.

Chemical looping combustion. Fuel conversion with inherent CO2 capture

Energy Technology Data Exchange (ETDEWEB)

Brandvoll, Oeyvind

2005-07-01

Chemical looping combustion (CLC) is a new concept for fuel energy conversion with CO2 capture. In CLC, fuel combustion is split into separate reduction and oxidation processes, in which a solid carrier is reduced and oxidized, respectively. The carrier is continuously recirculated between the two vessels, and hence direct contact between air and fuel is avoided. As a result, a stoichiometric amount of oxygen is transferred to the fuel by a regenerable solid intermediate, and CLC is thus a variant of oxy-fuel combustion. In principle, pure CO2 can be obtained from the reduction exhaust by condensation of the produced water vapour. The thermodynamic potential and feasibility of CLC has been studied by means of process simulations and experimental studies of oxygen carriers. Process simulations have focused on parameter sensitivity studies of CLC implemented in 3 power cycles; CLC-Combined Cycle, CLC-Humid Air Turbine and CLC-Integrated Steam Generation. Simulations indicate that overall fuel conversion ratio, oxidation temperature and operating pressure are among the most important process parameters in CLC. A promising thermodynamic potential of CLC has been found, with efficiencies comparable to, - or better than existing technologies for CO2 capture. The proposed oxygen carrier nickel oxide on nickel spinel (NiONiAl) has been studied in reduction with hydrogen, methane and methane/steam as well as oxidation with dry air. It has been found that at atmospheric pressure and temperatures above 600 deg C, solid reduction with dry methane occurs with overall fuel conversion of 92%. Steam methane reforming is observed along with methane cracking as side reactions, yielding an overall selectivity of 90% with regard to solid reduction. If steam is added to the reactant fuel, coking can be avoided. A methodology for long-term investigation of solid chemical activity in a batch reactor is proposed. The method is based on time variables for oxidation. The results for Ni

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

Fully solar-powered photoelectrochemical conversion for simultaneous energy storage and chemical sensing.

Science.gov (United States)

Wang, Yongcheng; Tang, Jing; Peng, Zheng; Wang, Yuhang; Jia, Dingsi; Kong, Biao; Elzatahry, Ahmed A; Zhao, Dongyuan; Zheng, Gengfeng

2014-06-11

We report the development of a multifunctional, solar-powered photoelectrochemical (PEC)-pseudocapacitive-sensing material system for simultaneous solar energy conversion, electrochemical energy storage, and chemical detection. The TiO2 nanowire/NiO nanoflakes and the Si nanowire/Pt nanoparticle composites are used as photoanodes and photocathodes, respectively. A stable open-circuit voltage of ∼0.45 V and a high pseudocapacitance of up to ∼455 F g(-1) are obtained, which also exhibit a repeating charging-discharging capability. The PEC-pseudocapacitive device is fully solar powered, without the need of any external power supply. Moreover, this TiO2 nanowire/NiO nanoflake composite photoanode exhibits excellent glucose sensitivity and selectivity. Under the sun light illumination, the PEC photocurrent shows a sensitive increase upon different glucose additions. Meanwhile in the dark, the open-circuit voltage of the charged pseudocapacitor also exhibits a corresponding signal over glucose analyte, thus serving as a full solar-powered energy conversion-storage-utilization system.

Coating technologies in the nuclear industry

International Nuclear Information System (INIS)

Kaae, J.L.

1993-01-01

Metallic, ceramic, and organic coatings are so commonly used in modern industry that virtually everyone can name several applications in which coatings are employed. Thus, it is no surprise that coating technologies are widely employed in the nuclear industry. Some of these technologies utilize processes that are mature and well developed, and others utilize processes that are new and state of the art. In this paper, five generic coating processes that include almost all vapor deposition processes are described, and then applications of each of these processes for deposition of specific materials in nuclear applications are described. These latter selections, of course, are very subjective, and others will be able to name other applications. Because of their wide range of application, coating technologies are considered to be national critical technologies. The generic coating processes that cover almost all vapor deposition technologies are as follows: (1) stationary substrate chemical vapor deposition; (2) fluidized bed chemical vapor deposition; (3) plasma-assisted chemical deposition; (4) sputtering; (5) evaporation

Novel Base Metal-Palladium Catalytic Diesel Filter Coating with NO2 Reducing Properties

DEFF Research Database (Denmark)

Johansen, K.; Dahl, S.; Mogensen, G.

2007-01-01

A novel alternative base metal/palladium coat has been developed that has limited NO2 formation and which even removes NO2 in a wide temperature range.Soot combustion, HC conversion and CO conversion properties are comparable to current platinum based solutions but the coating has a more attracti...... solutions. Furthermore, durability results from base metal/Pd coated DPFs installed on operating taxis and related tests cycle data is given....

Energy Conversion & Storage Program, 1993 annual report

Energy Technology Data Exchange (ETDEWEB)

Cairns, E.J.

1994-06-01

The Energy Conversion and Storage Program applies chemistry and materials science principles to solve problems in: production of new synthetic fuels; development of high-performance rechargeable batteries and fuel cells; development of high-efficiency thermochemical processes for energy conversion; characterization of complex chemical processes and chemical species; and the study and application of novel materials for energy conversion and transmission. Projects focus on transport-process principles, chemical kinetics, thermodynamics, chemical kinetics, thermodynamics, separation processes, organic and physical chemistry, novel materials, and advanced methods of analysis.

Photoelectrode Fabrication of Dye-Sensitized Nanosolar Cells Using Multiple Spray Coating Technique

Directory of Open Access Journals (Sweden)

Chien-Chih Chen

2013-01-01

Full Text Available This paper presents a spray coating technique for fabricating nanoporous film of photoelectrode in dye-sensitized nanosolar cells (DSSCs. Spray coating can quickly fabricate nanoporous film of the photoelectrode with lower cost, which can further help the DSSCs to be commercialized in the future. This paper analyzed photoelectric conversion efficiency of the DSSCs using spray coated photoelectrode in comparison with the photoelectrode made with the doctor blade method. Spray coating can easily control transmittance of the photoelectrode through the multiple spray coating process. This work mainly used a dispersant with help of ultrasonic oscillation to prepare the required nano-TiO2 solution and then sprayed it on the ITO glasses. In this work, a motor-operated conveyor belt was built to transport the ITO glasses automatically for multiple spray coating and drying alternately. Experiments used transmittance of the photoelectrode as a fabrication parameter to analyze photoelectric conversion efficiency of the DSSCs. The influencing factors of the photoelectrode transmittance during fabrication are the spray flow rate, the spray distance, and the moving speed of the conveyor belt. The results show that DSSC with the photoelectrode transmittance of ca. 68.0 ± 1.5% and coated by the spray coating technique has the best photoelectric conversion efficiency in this work.

Double coating protection of Nd–Fe–B magnets: Intergranular phosphating treatment and copper plating

International Nuclear Information System (INIS)

Zheng, Jingwu; Chen, Haibo; Qiao, Liang; Lin, Min; Jiang, Liqiang; Che, Shenglei; Hu, Yangwu

2014-01-01

In this work, a double coating protection technique of phosphating treatment and copper plating was made to improve the corrosion resistance of sintered Nd–Fe–B magnets. In other words, the intergranular region of sintered Nd–Fe–B is allowed to generate passive phosphate conversion coating through phosphating treatment, followed by the copper coating on the surface of sintered Nd–Fe–B. The morphology and corrosion resistance of the phosphated sintered Nd–Fe–B were observed using SEM and electrochemical method respectively. The phosphate conversion coating was formed more preferably on the intergranular region of sintered Nd–Fe–B than on the main crystal region; just after a short time of phosphating treatment, the intergranular region of sintered Nd–Fe–B has been covered by the phosphate conversion coating and the corrosion resistance is significantly improved. With the synergistic protection of the intergranular phosphorization and the followed copper electrodeposition, the corrosion resistance of the sintered Nd–Fe–B is significantly better than that with a single phosphate film or single plating protection. - Highlights: • We combined intergranular phosphating and copper plating to protect Nd–Fe–B. • The phosphate conversion coating was formed preferably on the intergranular region. • The phosphating coating can obviously improve the corrosion resistance of Nd–Fe–B. • The corrosion resistance of Nd–Fe–B was improved by double coating protection

Double coating protection of Nd–Fe–B magnets: Intergranular phosphating treatment and copper plating

Energy Technology Data Exchange (ETDEWEB)

Zheng, Jingwu; Chen, Haibo; Qiao, Liang [College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou 310014 (China); Lin, Min [Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Material Technology and Engineering Chinese Academy of Science, Ningbo 315201 (China); Jiang, Liqiang; Che, Shenglei [College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou 310014 (China); Hu, Yangwu, E-mail: 346648086@qq.com [College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou 310014 (China); Wenzhou Institute of Industry and Science, Wenzhou 325000 (China)

2014-12-15

In this work, a double coating protection technique of phosphating treatment and copper plating was made to improve the corrosion resistance of sintered Nd–Fe–B magnets. In other words, the intergranular region of sintered Nd–Fe–B is allowed to generate passive phosphate conversion coating through phosphating treatment, followed by the copper coating on the surface of sintered Nd–Fe–B. The morphology and corrosion resistance of the phosphated sintered Nd–Fe–B were observed using SEM and electrochemical method respectively. The phosphate conversion coating was formed more preferably on the intergranular region of sintered Nd–Fe–B than on the main crystal region; just after a short time of phosphating treatment, the intergranular region of sintered Nd–Fe–B has been covered by the phosphate conversion coating and the corrosion resistance is significantly improved. With the synergistic protection of the intergranular phosphorization and the followed copper electrodeposition, the corrosion resistance of the sintered Nd–Fe–B is significantly better than that with a single phosphate film or single plating protection. - Highlights: • We combined intergranular phosphating and copper plating to protect Nd–Fe–B. • The phosphate conversion coating was formed preferably on the intergranular region. • The phosphating coating can obviously improve the corrosion resistance of Nd–Fe–B. • The corrosion resistance of Nd–Fe–B was improved by double coating protection.

Formation of a cerium conversion coating on magnesium alloy using ascorbic acid as additive. Characterisation and anticorrosive properties of the formed films

OpenAIRE

A.P. Loperena; I.L. Lehr; S.B. Saidman.

2016-01-01

Cerium-based conversion coatings were formed on AZ91D magnesium alloy by immersion of the substrate in solutions containing Ce(NO3)3, H2O2 and ascorbic acid (HAsc). The characterisation of the films was performed by electrochemical and surface analysis techniques such as SEM, EDS, X-ray diffraction and X-ray photoelectron spectroscopy (XPS). The degree of corrosion protection achieved was evaluated in simulated physiological solution by the open circuit potential monitoring, polarisation tech...

Integrated Electrochemical Processes for CO₂ Capture and Conversion to Commodity Chemicals

Energy Technology Data Exchange (ETDEWEB)

Hatton, T. Alan [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Jamison, Timothy [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

2013-09-30

The Massachusetts Institute of Technology (MIT) and Siemens Corporations (SCR) are developing new chemical synthesis processes for commodity chemicals from CO₂. The process is assessed as a novel chemical sequestration technology that utilizes CO₂ from dilute gas streams generated at industrial carbon emitters as a raw material to produce useful commodity chemicals. Work at Massachusetts Institute of Technology (MIT) commenced on October 1st, 2010, and finished on September 30th, 2013. During this period, we have investigated and accomplished five objectives that mainly focused on converting CO₂ into high-value chemicals: 1) Electrochemical assessment of catalytic transformation of CO₂ and epoxides to cyclic carbonates; 2) Investigation of organocatalytic routes to convert CO₂ and epoxide to cyclic carbonates; 3) Investigation of CO₂ Capture and conversion using simple olefins under continuous flow; 4) Microwave assisted synthesis of cyclic carbonates from olefins using sodium bicarbonates in a green pathway; 5) Life cycle analyses of integrated chemical sequestration process. In this final report, we will describe the detailed study performed during the three year period and findings and conclusions drawn from our research.

Direct conversion of radioactive and chemical waste containing metals, ceramics, amorphous solids, and organics to glass

International Nuclear Information System (INIS)

Forsberg, C.W.; Beahm, E.C.; Parker, G.W.

1994-01-01

The Glass Material Oxidation and Dissolution System (CMODS) is a new process for direct conversion of radioactive, mixed, and chemical wastes to glass. The wastes can be in the chemical forms of metals, ceramics, amorphous solids, and organics. GMODS destroys organics and it incorporates heavy metals and radionuclides into a glass. Processable wastes may include miscellaneous spent fuels (SF), SF hulls and hardware, plutonium wastes in different forms, high-efficiency particulate air (HEPA) filters, ion-exchange resins, failed equipment, and laboratory wastes. Thermodynamic calculations indicate theoretical feasibility. Small-scale laboratory experiments (< 100 g per test) have demonstrated chemical laboratory feasibility for several metals. Additional work is needed to demonstrate engineering feasibility

The material balance of process of plasma-chemical conversion of polymer wastes into synthesis gas

International Nuclear Information System (INIS)

Tazmeev, A Kh; Tazmeeva, R N

2017-01-01

The process of conversion of polymer wastes in the flow of water-steam plasma which are created by the liquid electrodes plasma generators was experimentally studied. The material balance was calculated. The regularities of the participating of hydrogen and oxygen which contained in the water-steam plasma, in formation of chemical compounds in the final products were revealed. (paper)

The material balance of process of plasma-chemical conversion of polymer wastes into synthesis gas

Science.gov (United States)

Tazmeev, A. Kh; Tazmeeva, R. N.

2017-01-01

The process of conversion of polymer wastes in the flow of water-steam plasma which are created by the liquid electrodes plasma generators was experimentally studied. The material balance was calculated. The regularities of the participating of hydrogen and oxygen which contained in the water-steam plasma, in formation of chemical compounds in the final products were revealed.

Surface-dependent chemical equilibrium constants and capacitances for bare and 3-cyanopropyldimethylchlorosilane coated silica nanochannels

DEFF Research Database (Denmark)

Andersen, Mathias Bækbo; Frey, Jared; Pennathur, Sumita

2011-01-01

, and pK+ are constant and independent of surface composition. Our theoretical model consists of three parts: (i) a chemical equilibrium model of the bare or coated wall, (ii) a chemical equilibrium model of the buffered bulk electrolyte, and (iii) a self-consistent Gouy–Chapman–Stern triple-layer model...... of the electrochemical double layer coupling these two equilibrium models. To validate our model, we used both pH-sensitive dye-based capillary filling experiments as well as electro-osmotic current-monitoring measurements. Using our model we predict the dependence of ζ potential, surface charge density, and capillary...

Mixed zirconia calcium phosphate coatings for dental implants: Tailoring coating stability and bioactivity potential

International Nuclear Information System (INIS)

Pardun, Karoline; Treccani, Laura; Volkmann, Eike; Streckbein, Philipp; Heiss, Christian; Destri, Giovanni Li; Marletta, Giovanni; Rezwan, Kurosch

2015-01-01

Enhanced coating stability and adhesion are essential for long-term success of orthopedic and dental implants. In this study, the effect of coating composition on mechanical, physico-chemical and biological properties of coated zirconia specimens is investigated. Zirconia discs and dental screw implants are coated using the wet powder spraying (WPS) technique. The coatings are obtained by mixing yttria-stabilized zirconia (TZ) and hydroxyapatite (HA) in various ratios while a pure HA coating served as reference material. Scanning electron microscopy (SEM) and optical profilometer analysis confirm a similar coating morphology and roughness for all studied coatings, whereas the coating stability can be tailored with composition and is probed by insertion and dissections experiments in bovine bone with coated zirconia screw implants. An increasing content of calcium phosphate (CP) resulted in a decrease of mechanical and chemical stability, while the bioactivity increased in simulated body fluid (SBF). In vitro experiments with human osteoblast cells (HOB) revealed that the cells grew well on all samples but are affected by dissolution behavior of the studied coatings. This work demonstrates the overall good mechanical strength, the excellent interfacial bonding and the bioactivity potential of coatings with higher TZ contents, which provide a highly interesting coating for dental implants. - Highlights: • Different ratios of zirconia (TZ) and calcium phosphate (CP) were deposited on zirconia substrates. • Enhancement of TZ content in mixed coatings increased coating stability. • Enhancement of CP content in mixed coatings increased bioactivity. • All tested coating compositions were non-toxic

Mixed zirconia calcium phosphate coatings for dental implants: Tailoring coating stability and bioactivity potential

Energy Technology Data Exchange (ETDEWEB)

Pardun, Karoline [University of Bremen, Advanced Ceramics, Am Biologischen Garten 2, 28359 Bremen (Germany); Treccani, Laura, E-mail: treccani@uni-bremen.de [University of Bremen, Advanced Ceramics, Am Biologischen Garten 2, 28359 Bremen (Germany); Volkmann, Eike [University of Bremen, Advanced Ceramics, Am Biologischen Garten 2, 28359 Bremen (Germany); Streckbein, Philipp [University Hospital, Justus-Liebig-University Giessen, Department of Cranio-Maxillo-Facial Surgery, Klinikstrasse 33, 35385 Giessen (Germany); Heiss, Christian [University Hospital of Giessen-Marburg, Department of Trauma Surgery, Rudolf-Buchheim-Strasse 7, 35385 Giessen, Germany, (Germany); Laboratory of Experimental Surgery, Kerkraderstrasse 9, 35392 Giessen (Germany); Destri, Giovanni Li; Marletta, Giovanni [Laboratory for Molecular Surfaces and Nanotechnology (LAMSUN), Department of Chemistry, University of Catania and CSGI, Viale A. Doria 6, 95125 Catania (Italy); Rezwan, Kurosch [University of Bremen, Advanced Ceramics, Am Biologischen Garten 2, 28359 Bremen (Germany)

2015-03-01

Enhanced coating stability and adhesion are essential for long-term success of orthopedic and dental implants. In this study, the effect of coating composition on mechanical, physico-chemical and biological properties of coated zirconia specimens is investigated. Zirconia discs and dental screw implants are coated using the wet powder spraying (WPS) technique. The coatings are obtained by mixing yttria-stabilized zirconia (TZ) and hydroxyapatite (HA) in various ratios while a pure HA coating served as reference material. Scanning electron microscopy (SEM) and optical profilometer analysis confirm a similar coating morphology and roughness for all studied coatings, whereas the coating stability can be tailored with composition and is probed by insertion and dissections experiments in bovine bone with coated zirconia screw implants. An increasing content of calcium phosphate (CP) resulted in a decrease of mechanical and chemical stability, while the bioactivity increased in simulated body fluid (SBF). In vitro experiments with human osteoblast cells (HOB) revealed that the cells grew well on all samples but are affected by dissolution behavior of the studied coatings. This work demonstrates the overall good mechanical strength, the excellent interfacial bonding and the bioactivity potential of coatings with higher TZ contents, which provide a highly interesting coating for dental implants. - Highlights: • Different ratios of zirconia (TZ) and calcium phosphate (CP) were deposited on zirconia substrates. • Enhancement of TZ content in mixed coatings increased coating stability. • Enhancement of CP content in mixed coatings increased bioactivity. • All tested coating compositions were non-toxic.

Physico-chemical conversion of sulphur dioxide in a power plant plume

International Nuclear Information System (INIS)

Lewin, E.E.

1978-03-01

A review is given of the actual knowledge of SO 2 atmospheric processes gained from laboratory and field experiments. Implementation is described of the instrumentation, operational procedures and analytical methods in connection with a field study of the conversion and dispersion of SO 2 in an oil-fired power plant plume. Furthermore, the preliminary results are included of five experiments performed until the end of 1976. Measurements were performed from an aircraft and included continuous registration of NOsub(x), SO 2 , SF 6 , and particle concentrations, as well as temperature and humidity. It was planned to label sulphur from the source in question with sulphur-35. However, this part of the experiment had to be abandoned because of public opinion on the use of radioactive tracers. Sulphur hexafluoride was used as an internal tracer for the plume. A half-life for SO 2 of about 30 min was determined from one of the experiments. In this connection the possibility of using NOsub(x) as a conservative tracer is shown. Possible ways of removal are discussed and the rate of two of the processes is calculated by means of a model describing the chemical conversion in a dispersing plume. (author)

Micro-thermal analysis of polyester coatings

NARCIS (Netherlands)

Fischer, H.R.

2010-01-01

The application and suitability of micro-thermal analysis to detect changes in the chemical and physical properties of coating due to ageing and especially photo-degradation is demonstrated using a model polyester coating based on neopentyl glycol isophthalic acid. The changes in chemical structure

Magnesium carbide synthesis from methane and magnesium oxide - a potential methodology for natural gas conversion to premium fuels and chemicals

Energy Technology Data Exchange (ETDEWEB)

Diaz, A.F.; Modestino, A.J.; Howard, J.B. [Massachusetts Institute of Technology, Cambridge, MA (United States)] [and others

1995-12-31

Diversification of the raw materials base for manufacturing premium fuels and chemicals offers U.S. and international consumers economic and strategic benefits. Extensive reserves of natural gas in the world provide a valuable source of clean gaseous fuel and chemical feedstock. Assuming the availability of suitable conversion processes, natural gas offers the prospect of improving flexibility in liquid fuels and chemicals manufacture, and thus, the opportunity to complement, supplement, or displace petroleum-based production as economic and strategic considerations require. The composition of natural gas varies from reservoir to reservoir but the principal hydrocarbon constituent is always methane (CH{sub 4}). With its high hydrogen-to-carbon ratio, methane has the potential to produce hydrogen or hydrogen-rich products. However, methane is a very chemically stable molecule and, thus, is not readily transformed to other molecules or easily reformed to its elements (H{sub 2} and carbon). In many cases, further research is needed to augment selectivity to desired product(s), increase single-pass conversions, or improve economics (e.g. there have been estimates of $50/bbl or more for liquid products) before the full potential of these methodologies can be realized on a commercial scale. With the trade-off between gas conversion and product selectivity, a major challenge common to many of these technologies is to simultaneously achieve high methane single-pass conversions and high selectivity to desired products. Based on the results of the scoping runs, there appears to be strong indications that a breakthrough has finally been achieved in that synthesis of magnesium carbides from MgO and methane in the arc discharge reactor has been demonstrated.

ETV Program Report: Coatings for Wastewater Collection ...

Science.gov (United States)

The Standard Cement Materials, Inc. Standard Epoxy Coating 4553™ (SEC 4553) epoxy coating used for wastewater collection system rehabilitation was evaluated by EPA’s Environmental Technology Verification Program under laboratory conditions at the Center for Innovative Grouting Material and Technology (CIGMAT) Laboratory at the University of Houston. Testing was conducted over a period of six months to evaluate the coating’s (1) chemical resistance and (2) bonding strength for infrastructure applications. For chemical resistance, coated concrete and clay bricks with holidays (holes created in the coating) were used to evaluate the chemical resistance of the coating/substrate bond under a corrosive environment. Twenty coated concrete (dry and wet) and 20 coated clay brick (dry and wet) specimens were exposed to DI water and sulfuric acid solution (pH=1), and the specimens were visually inspected and weight changes measured. Evaluation of the coating-to-substrate bonding strength was determined using two modified ASTM test methods – one to determine bond strength of the coating with two specimens sandwiched together using the coating, and the second to determine the bond strength by applying a tensile load to the coating applied to specimens of each substrate. Forty-eight bonding tests were performed over the six month evaluation. The tests resulted in the following conclusions about Standard Cement’s SEC 4553 coating: • After the six-month chemi

Status and perspectives of CO2 conversion into fuels and chemicals by catalytic, photocatalytic and electrocatalytic processes

NARCIS (Netherlands)

Kondratenko, E.V.; Mul, Guido; Baltrusaitis, Jonas; Larrazábal, G.O.; Pérez-Ramírez, J.

2013-01-01

This review highlights recent developments and future perspectives in carbon dioxide usage for the sustainable production of energy and chemicals and to reduce global warming. We discuss the heterogeneously catalysed hydrogenation, as well as the photocatalytic and electrocatalytic conversion of CO2

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

Deposition characteristics of titanium coating deposited on SiC fiber by cold-wall chemical vapor deposition

Energy Technology Data Exchange (ETDEWEB)

Luo, Xian, E-mail: luo_shenfan@hotmail.com; Wu, Shuai; Yang, Yan-qing; Jin, Na; Liu, Shuai; Huang, Bin

2016-12-01

The deposition characteristics of titanium coating on SiC fiber using TiCl{sub 4}-H{sub 2}-Ar gas mixture in a cold-wall chemical vapor deposition were studied by the combination of thermodynamic analysis and experimental studies. The thermodynamic analysis of the reactions in the TiCl{sub 4}-H{sub 2}-Ar system indicates that TiCl{sub 4} transforms to titanium as the following paths: TiCl{sub 4} → TiCl{sub 3} → Ti, or TiCl{sub 4} → TiCl{sub 3} → TiCl{sub 2} → Ti. The experimental results show that typical deposited coating contains two distinct layers: a TiC reaction layer close to SiC fiber and titanium coating which has an atomic percentage of titanium more than 70% and that of carbon lower than 30%. The results illustrate that a carbon diffusion barrier coating needs to be deposited if pure titanium is to be prepared. The deposition rate increases with the increase of temperature, but higher temperature has a negative effect on the surface uniformity of titanium coating. In addition, appropriate argon gas flow rate has a positive effect on smoothing the surface morphology of the coating. - Highlights: • Both thermodynamic analysis and experimental studies were adopted in this work. • The transformation paths of TiCl{sub 4} to Ti is: TiCl{sub 4} → TiCl{sub 3} → Ti, or TiCl{sub 4} → TiCl{sub 3} → TiCl{sub 2} → Ti. • Typical deposited Ti coating on SiC fiber contained two distinct layers. • Deposition temperature is important on deposition rate and morphologies. • Appropriate argon gas flow rate has a positive effect on smoothing of the coating.

Hexavalent Chrome Free Coatings for Electronics; Electromagnetic Interference (EMI) Shielding Effectiveness (SE)

Science.gov (United States)

Kessel, Kurt R.

2014-01-01

The purpose of this testing is to determine the suitability of trivalent chromium conversion coatings that meet the requirements of MIL-DTL-5541, Type II, for use in applications where high-frequency electrical performance is important. This project will evaluate the ability of coated aluminum to form adequate EMI seals. Testing will assess performance of the trivalent chromium coatings against the known control hexavalent chromium MIL-DTL-5541 Type I Class 3 before and after they have been exposed to a set of environmental conditions. Performance will be assessed by evaluating shielding effectiveness (SE) test data from a variety of test samples comprised of different aluminum types and/or conversion coatings.

Catalytic Conversion of Carbohydrates

DEFF Research Database (Denmark)

Osmundsen, Christian Mårup

a renewable route to aromatics. The conversion of biomass by high temperature processes is a desirable prospect due to the high volumetric production rates which can be achieved, and the ability of these types of processes to convert a wide range of substrates. Current processes however typically have rather...... with the production of commodity chemicals from the most abundantly available renewable source of carbon, carbohydrates. The production of alkyl lactates by the Lewis acid catalyzed conversion of hexoses is an interesting alternative to current fermentation based processes. A range of stannosilicates were...... to be an efficient initial conversion step in the utilization of biomass for chemicals production. The shift from an oil based chemical industry to one based on renewable resources is bound to happen sooner or later, however the environmental problems associated with the burning of fossil resources means...

Final Test Report: Hexavalent Chrome Free Coatings for Electronics Electromagnetic Interference (EMI) Shielding Effectiveness (SE)

Science.gov (United States)

Kessel, Kurt R.

2016-01-01

The test results for Salt Spray Resistance, Static Heat and Humidity and Marine Environment can be found in Sections 3.1.3.3, 3.1.4.3 and 3.1.5.3 respectively. In summary, both the Metalast TCP and SurTec 650 Type 2 conversion coatings perform very similar to the incumbent Type 1 conversion coating against both 6061 and 5052 aluminum under all three test conditions. Significant prior work was performed to select the aluminum and conversion coating included within this test cycle; Reference - NASA GSDO Program Hexavalent Chrome Alternatives Final Pretreatments Test Report Task Order: NNH12AA45D September 01, 2013. As illustrated in the data, the 6061 aluminum panels SLIGHTLY out-performed the 5052 aluminum panels. Individual shielding effectiveness graphs for each panel are included within Appendix C and D. One other notable effect found during review of the data is that the Test Panels exposed to B117 Salt Fog reduced in shielding effectiveness significantly more than the Marine Environment Test Panels. The shielding effectiveness of the Marine Test Panels was approximately 20dB higher than the Test Panels that underwent B117 Salt Fog Exposure. The intent of this evaluation was not to maximize shielding effectiveness values. The same Parker Chomerics Cho-Seal 6503 gasket material was used for all panels with aluminum and conversion coating variants. A typical EMI gasket design for corrosive environments would be done quite differently. The intent was to execute a test that would provide the best possible evaluation of different aluminum materials and conversion coatings in corrosive environments. The test program achieved this intent. The fact that the two aluminums and two Type II conversion coatings performed similar to the incumbent Type 1 conversion coating is a positive outcome. It was desired to have an outcome that further differentiation the performance of two aluminum types and two conversion coating types but this could not be extracted by the test

Influence of culture media on the physical and chemical properties of Ag-TiCN coatings

Science.gov (United States)

Carvalho, I.; Escobar Galindo, R.; Henriques, M.; Palacio, C.; Carvalho, S.

2014-08-01

The aim of this study was to verify the possible physical and chemical changes that may occur on the surface of Ag-TiCN coatings after exposure to the culture media used in microbiological and cytotoxic assays, respectively tryptic soy broth (TSB) and Dulbecco's modified eagle's medium (DMEM). After sample immersion for 24 h in the media, analyses were performed by glow discharge optical emission spectroscopy discharge radiation (GDOES), Rutherford backscattering spectroscopy (RBS) and x-ray photoelectron spectroscopy (XPS). The results of GDOES profile, RBS and XPS spectra, of samples immersed in TSB, demonstrated the formation of a thin layer of carbon, oxygen and nitrogen that could be due to the presence of proteins in TSB. After 24 h of immersion in DMEM, the results showed the formation of a thin layer of calcium phosphates on the surface, since the coatings displayed a highly oxidized surface in which calcium and phosphorus were detected. All these results suggested that the formation of a layer on the coating surface prevented the release of silver ions in concentrations that allow antibacterial activity.

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

Science.gov (United States)

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

2018-04-01

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

Fiscal 1997 report on the results on the international standardization R and D. Development of chemical methods to analyze/evaluate metallic coatings of surface treated steel coating sheets; 1997 nendo seika hokokusho kokusai hyojun soseigata kenkyu kaihatsu. Hyomen shori koban mekkiso no kagaku bunseki hyoka hoho no kaihatsu

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-03-01

The paper studied the international standardization of the chemical analysis method and glow discharge optical emission spectrometry. Chemical composition and coating thickness (g/m{sup 2}) of 14 kinds of specimens including alloy coatings and organic coating with zinc and aluminum as base were analyzed by the above-mentioned methods to examine the relation between the both. As the chemical analysis method, used was inductively coupled plasma atomic emission spectrometry. To study the relation between the methods, it was found to be necessary to recognize morphology at the boundary between the coating and base steel using, for example, scanning electron microscope (SEM) and electro-probe micro-analysis (EPMA). To measure traceability of the analysis method, with the chemical analysis method as a judgement method, it is necessary to make reference materials by coating materials, to use the calibration graph confirmed by the materials and to adopt the glow discharge optical emission spectrometry. On the basis of such way of thinking, drafts were worked out for the international standardization of the chemical analysis method and glow discharge optical emission spectrometry. 7 refs., 117 figs., 33 tabs.

Formation, adhesion and mechanical/chemical properties of protective coatings

International Nuclear Information System (INIS)

Mattox, D.M.

1979-01-01

Some general considerations for protective coatings are discussed. It is suggested that ceramic coatings may provide a class of coatings applicable to high temperature turbine blades for use in a corrosive/erosive environment. In particular, the ceraming glass materials would seem to hold promise, but little or nothing has been done on depositing these materials by vacuum processes

Uranium conversion; Urankonvertering

Energy Technology Data Exchange (ETDEWEB)

Oliver, Lena; Peterson, Jenny; Wilhelmsen, Katarina [Swedish Defence Research Agency (FOI), Stockholm (Sweden)

2006-03-15

FOI, has performed a study on uranium conversion processes that are of importance in the production of different uranium compounds in the nuclear industry. The same conversion processes are of interest both when production of nuclear fuel and production of fissile material for nuclear weapons are considered. Countries that have nuclear weapons ambitions, with the intention to produce highly enriched uranium for weapons purposes, need some degree of uranium conversion capability depending on the uranium feed material available. This report describes the processes that are needed from uranium mining and milling to the different conversion processes for converting uranium ore concentrate to uranium hexafluoride. Uranium hexafluoride is the uranium compound used in most enrichment facilities. The processes needed to produce uranium dioxide for use in nuclear fuel and the processes needed to convert different uranium compounds to uranium metal - the form of uranium that is used in a nuclear weapon - are also presented. The production of uranium ore concentrate from uranium ore is included since uranium ore concentrate is the feed material required for a uranium conversion facility. Both the chemistry and principles or the different uranium conversion processes and the equipment needed in the processes are described. Since most of the equipment that is used in a uranium conversion facility is similar to that used in conventional chemical industry, it is difficult to determine if certain equipment is considered for uranium conversion or not. However, the chemical conversion processes where UF{sub 6} and UF{sub 4} are present require equipment that is made of corrosion resistant material.

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...

Diamond-like carbon coatings on a CoCrMo implant alloy: A detailed XPS analysis of the chemical states at the interface

International Nuclear Information System (INIS)

Mueller, U.; Falub, C.V.; Thorwarth, G.; Voisard, C.; Hauert, R.

2011-01-01

Low friction and wear resistant coatings have a long history of successful applications in industry. It has long been hoped that these coatings, especially diamond-like carbon (DLC), could also be used successfully in load-bearing joint implants, extending implant life time considerably. However, despite several medical studies carried out so far, no regular DLC-coated implants are available on the market. In most cases, failure was due to insufficient long-term stability of the adhesion of such coatings on implants in vivo. That is because introducing a coated implant not only brings the coating into contact with the body environment but also the interface that controls the adhesion. This usually reactively formed interface must be considered to be at least one additional material which must be not only biocompatible, but also unsusceptible to corrosive attack. The aim of this paper is to analyze in detail the interface, i.e., the transition region between the substrate and the coating. This knowledge is necessary in order to find the right measures to ensure the long-term stability of the adhesion. Results for DLC coatings on a cobalt-chromium-molybdenum alloy are presented. It is shown that a very thin interface layer is formed, with the alloy on one side and the carbon film on the other side. This layer consists of a mixture of carbides from all the metals of the base material. This result is obtained by means of measuring depth profiles using X-ray photoelectron spectroscopy because these spectra yield not only the chemical composition of the interface but a detailed analysis provides information on the chemical states across the interface.

UV-LED Curing Efficiency of Wood Coatings

Directory of Open Access Journals (Sweden)

Véronic Landry

2015-12-01

Full Text Available Ultraviolet light emitting diodes (UV-LEDs have attracted great interest in recent years. They can be used to polymerize coatings, such as those used for prefinished wood flooring. In this project, two lamps were compared for their suitability to be used on a wood flooring finishing line: a UV-microwave and a UV-LED lamp. Low heat emission was found for the UV-LED lamp compared to the UV-microwave one. This study also reveals that the 4 W/cm2 UV-LED lamp used is not powerful enough to cure UV high solids acrylate coatings while satisfactory results can be obtained for UV water-based formulations. In fact, conversion percentages were found to be low for the high solids coatings, leaving the coatings tacky. Higher conversion percentages were obtained for the UV water-based formulations. As a result, mass loss, hardness, and scratch resistance found for the samples cured by UV-LED were closed to the ones found for the samples cured using the UV microwave lamp.

Recent Advances in Photoelectrochemical Applications of Silicon Materials for Solar-to-Chemicals Conversion.

Science.gov (United States)

Zhang, Doudou; Shi, Jingying; Zi, Wei; Wang, Pengpeng; Liu, Shengzhong Frank

2017-11-23

Photoelectrochemical (PEC) technology for the conversion of solar energy into chemicals requires cost-effective photoelectrodes to efficiently and stably drive anodic and/or cathodic half-reactions to complete the overall reactions for storing solar energy in chemical bonds. The shared properties among semiconducting photoelectrodes and photovoltaic (PV) materials are light absorption, charge separation, and charge transfer. Earth-abundant silicon materials have been widely applied in the PV industry, and have demonstrated their efficiency as alternative photoabsorbers for photoelectrodes. Many efforts have been made to fabricate silicon photoelectrodes with enhanced performance, and significant progress has been achieved in recent years. Herein, recent developments in crystalline and thin-film silicon-based photoelectrodes (including amorphous, microcrystalline, and nanocrystalline silicon) immersed in aqueous solution for PEC hydrogen production from water splitting are summarized, as well as applications in PEC CO 2 reduction and PEC regeneration of discharged species in redox flow batteries. Silicon is an ideal material for the cost-effective production of solar chemicals through PEC methods. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Observation of inner surface of flame-tower type reactor for uranium conversion

International Nuclear Information System (INIS)

Amamoto, Ippei; Terai, Takayuki; Umetsu, Hiroshi

2003-01-01

A fluorination reactor, which has been used to convert uranium tetrafluoride (UF 4 ) into uranium hexafluoride (UF 6 ), was completed after approximately 6000 hours operation at the uranium conversion facility in Japan. The observation of its inner surface was carried out to understand its corrosive condition and mechanism. The main wall of the reactor is made of Monel Alloy and its operational temperature is approximately 450degC at external surface under gaseous fluorine atmosphere. A sampling was undertaken from the most corrosive part of the reactor wall, and its analysis was carried out to obtain the data for the condition of appearance, thickness, macro and micro structure, etc. The results of observation are as follows: (1) The thickness decreased evenly (average 3.9 mm/year); (2) The chemical composition of corrosive products as coating was mainly nickel fluoride (NiF 2 ), which suggested that the corrosion mechanism could have been caused by the high temperature gas corrosion; (3) The total amount of coating was lower than that of a loss in thickness. For some reason, some of coating would seem to become extinct on the surface of the wall. The deterioration of coating, which formed a protector on the wall due to excess heating of the wall, the sand erosion effect by UF 4 , etc. have contributed to this state of condition. (author)

One-step spray-coating process for the fabrication of colorful superhydrophobic coatings with excellent corrosion resistance.

Science.gov (United States)

Li, Jian; Wu, Runni; Jing, Zhijiao; Yan, Long; Zha, Fei; Lei, Ziqiang

2015-10-06

A simple method was used to generate colorful hydrophobic stearate particles via chemical reactions between inorganic salts and sodium stearate. Colored self-cleaning superhydrophobic coatings were prepared through a facile one-step spray-coating process by spraying the stearate particle suspensions onto stainless steel substrates. Furthermore, the colorful superhydrophobic coating maintains excellent chemical stability under both harsh acidic and alkaline circumstances. After being immersed in a 3.5 wt % NaCl aqueous solution for 1 month, the as-prepared coatings remained superhydrophobic; however, they lost their self-cleaning property with a sliding angle of about 46 ± 3°. The corrosion behavior of the superhydrophobic coatings on the Al substrate was characterized by the polarization curve and electrochemical impedance spectroscopy (EIS). The electrochemical corrosion test results indicated that the superhydrophobic coatings possessed excellent corrosion resistance, which could supply efficient and long-term preservation for the bare Al substrate.

Trends and Challenges in Catalytic Biomass Conversion

DEFF Research Database (Denmark)

Osmundsen, Christian Mårup; Egeblad, Kresten; Taarning, Esben

2013-01-01

The conversion of biomass to the plethora of chemicals used in modern society is one of the major challenges of the 21st century. Due to the significant differences between biomass resources and the current feedstock, crude oil, new technologies need to be developed encompassing all steps...... in the value chain, from pretreatment to purification. Heterogeneous catalysis is at the heart of the petrochemical refinery and will likely play an equally important role in the future biomass-based chemical industry. Three potentially important routes to chemicals from biomass are highlighted in this chapter....... The conversion of biomass-derived substrates, such as glycerol, by hydrogenolysis to the important chemicals ethylene glycol and propane diols. Secondly, the conversion of carbohydrates by Lewis acidic zeolites to yield alkyl lactates, and finally the conversion of lignin, an abundant low value source of biomass...

Preparation of Ti species coating hydrotalcite by chemical vapor deposition for photodegradation of azo dye.

Science.gov (United States)

Xiao, Gaofei; Zeng, HongYan; Xu, Sheng; Chen, ChaoRong; Zhao, Quan; Liu, XiaoJun

2017-10-01

TiO 2 in anatase crystal phase is a very effective catalyst in the photocatalytic oxidation of organic compounds in water. To improve its photocatalytic activity, the Ti-coating MgAl hydrotalcite (Ti-MgAl-LDH) was prepared by chemical vapor deposition (CVD) method. Response surface method (RSM) was employed to evaluate the effect of Ti species coating parameters on the photocatalytic activity, which was found to be affected by the furnace temperature, N 2 flow rate and influx time of precursor gas. Application of RSM successfully increased the photocatalytic efficiency of the Ti-MgAl-LDH in methylene blue photodegradation under UV irradiation, leading to improved economy of the process. According to the results from X-ray diffraction, scanning electron microscopy, Brunner-Emmet-Teller and Barrett-Joyner-Hallender, thermogravimetric and differential thermal analysis, UV-vis diffuse reflectance spectra analyses, the Ti species (TiO 2 or/and Ti 4+ ) were successfully coated on the MgAl-LDH matrix. The Ti species on the surface of the Ti-MgAl-LDH lead to a higher photocatalytic performance than commercial TiO 2 -P25. The results suggested that CVD method provided a new approach for the industrial preparation of Ti-coating MgAl-LDH material with good photocatalytic performances. Copyright © 2017. Published by Elsevier B.V.

Carbide coated fibers in graphite-aluminum composites

Science.gov (United States)

Imprescia, R. J.; Levinson, L. S.; Reiswig, R. D.; Wallace, T. C.; Williams, J. M.

1975-01-01

The NASA-supported program at the Los Alamos Scientific Laboratory (LASL) to develop carbon fiber-aluminum matrix composites is described. Chemical vapor deposition (CVD) was used to uniformly deposit thin, smooth, continuous coats of TiC on the fibers of graphite tows. Wet chemical coating of fibers, followed by high-temperature treatment, was also used, but showed little promise as an alternative coating method. Strength measurements on CVD coated fiber tows showed that thin carbide coats can add to fiber strength. The ability of aluminum alloys to wet TiC was successfully demonstrated using TiC-coated graphite surfaces. Pressure-infiltration of TiC- and ZrC-coated fiber tows with aluminum alloys was only partially successful. Experiments were performed to evaluate the effectiveness of carbide coats on carbon as barriers to prevent reaction between alluminum alloys and carbon. Initial results indicate that composites of aluminum and carbide-coated graphite are stable for long periods of time at temperatures near the alloy solidus.

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)

Carbon dioxide conversion to fuels and chemicals using a hybrid green process

International Nuclear Information System (INIS)

Ramachandriya, Karthikeyan D.; Kundiyana, Dimple K.; Wilkins, Mark R.; Terrill, Jennine B.; Atiyeh, Hasan K.; Huhnke, Raymond L.

2013-01-01

Highlights: • A unique CO 2 conversion technology using microorganisms was demonstrated. • Corn steep liquor medium enhanced production of n-butanol and n-hexanol. • Cotton seed extract (CSE) medium promoted ethanol formation. • CSE medium without morpholinoethanesulfonic acid buffer reduced the cost by 99%. - Abstract: A unique hybrid technology that uses renewable hydrogen (H 2 ) and carbon dioxide (CO 2 ) sequestered from large point sources, to produce fuels and chemicals has been proposed and tested. The primary objective of this research was to determine the feasibility of using two acetogenic bacteria to metabolize H 2 and CO 2 for the production of ethanol. Three experiments were conducted in small scale reactors to select a bacterium, feed gas composition and nutrient medium source to produce ethanol. The results indicated that Clostridium carboxidivorans produced 33% more ethanol and 66% less acetic acid compared to Clostridium ragsdalei, making C. carboxidivorans the better candidate for ethanol production. Furthermore, the removal of morpholinoethanesulfonic acid (MES) buffer from cotton seed extract (CSE) medium offered a low-cost medium for fermentations. Additionally, we observed that corn steep liquor (CSL) in the medium diversified the product range with both bacteria. Maximum concentrations of ethanol, n-butanol, n-hexanol, acetic acid, butyric acid, and hexanoic acid from different fermentation treatments were 2.78 g L −1 , 0.70 g L −1 , 0.52 g L −1 , 4.06 g L −1 , 0.13 g L −1 and 0.42 g L −1 , respectively. This study highlights the important role that acetogenic microbes can offer for CO 2 conversion into valuable fuels and chemicals

The Tribological Behaviors of Three Films Coated on Biomedical Titanium Alloy by Chemical Vapor Deposition

Science.gov (United States)

Wang, Song; Liao, Zhenhua; Liu, Yuhong; Liu, Weiqiang

2015-11-01

Three thin films (DLC, a-C, and TiN) were performed on Ti6Al4V by chemical vapor deposition. Carbon ion implantation was pretreated for DLC and a-C films while Ti transition layer was pretreated for TiN film to strengthen the bonding strength. X-ray diffraction, Raman measurement, nano-hardness and nano-scratch tester, and cross-section etching by FIB method were used to analyze film characteristics. Tribological behaviors of these coatings were studied by articulation with both ZrO2 and UHMWPE balls using ball-on-disk sliding. The thickness values reached ~0.46, ~0.33, and ~1.67 μm for DLC, a-C, and TiN film, respectively. Nano-hardness of the coatings compared with that of untreated and bonding strength (critical load in nano-scratch test) values of composite coatings compared with that of monolayer film all increased significantly, respectively. Under destructive test (ZrO2 ball conterface) in bovine serum lubrication, TiN coating revealed the best wear resistance while DLC showed the worst. Film failure was mainly attributed to the plowing by hard ZrO2 ball characterized by abrasive and adhesive wear. Under normal test (UHMWPE ball conterface), all coatings showed significant improvement in wear resistance both in dry sliding and bovine serum lubrication. Both DLC and a-C films showed less surface damage than TiN film due to the self-lubricating phenomenon in dry sliding. TiN film showed the largest friction coefficient both in destructive and normal tests, devoting to the big TiN grains thus leading to much rougher surface and then a higher value. The self-lubricating film formed on DLC and a-C coating could also decrease their friction coefficients. The results indicated that three coatings revealed different wear mechanisms, and thick DLC or a-C film was more promising in application in lower stress conditions such as artificial cervical disk.

Bonding Characteristics and Chemical Inertness of Zr–Si–N Coatings with a High Si Content in Glass Molding

Directory of Open Access Journals (Sweden)

Li-Chun Chang

2018-05-01

Full Text Available High-Si-content transition metal nitride coatings, which exhibited an X-ray amorphous phase, were proposed as protective coatings on glass molding dies. In a previous study, the Zr–Si–N coatings with Si contents of 24–30 at.% exhibited the hardness of Si3N4, which was higher than those of the middle-Si-content (19 at.% coatings. In this study, the bonding characteristics of the constituent elements of Zr–Si–N coatings were evaluated through X-ray photoelectron spectroscopy. Results indicated that the Zr 3d5/2 levels were 179.14–180.22 and 180.75–181.61 eV for the Zr–N bonds in ZrN and Zr3N4 compounds, respectively. Moreover, the percentage of Zr–N bond in the Zr3N4 compound increased with increasing Si content in the Zr–Si–N coatings. The Zr–N bond of Zr3N4 dominated when the Si content was >24 at.%. Therefore, high Si content can stabilize the Zr–N compound in the M3N4 bonding structure. Furthermore, the thermal stability and chemical inertness of Zr–Si–N coatings were evaluated by conducting thermal cycle annealing at 270 °C and 600 °C in a 15-ppm O2–N2 atmosphere. The results indicated that a Zr22Si29N49/Ti/WC assembly was suitable as a protective coating against SiO2–B2O3–BaO-based glass for 450 thermal cycles.

Porous Organic Nanolayers for Coating of Solid-state Devices

Science.gov (United States)

2011-01-01

Background Highly hydrophobic surfaces can have very low surface energy and such low surface energy biological interfaces can be obtained using fluorinated coatings on surfaces. Deposition of biocompatible organic films on solid-state surfaces is attained with techniques like plasma polymerization, biomineralization and chemical vapor deposition. All these require special equipment or harsh chemicals. This paper presents a simple vapor-phase approach to directly coat solid-state surfaces with biocompatible films without any harsh chemical or plasma treatment. Hydrophilic and hydrophobic monomers were used for reaction and deposition of nanolayer films. The monomers were characterized and showed a very consistent coating of 3D micropore structures. Results The coating showed nano-textured surface morphology which can aid cell growth and provide rich molecular functionalization. The surface properties of the obtained film were regulated by varying monomer concentrations, reaction time and the vacuum pressure in a simple reaction chamber. Films were characterized by contact angle analysis for surface energy and with profilometer to measure the thickness. Fourier Transform Infrared Spectroscopy (FTIR) analysis revealed the chemical composition of the coated films. Variations in the FTIR results with respect to different concentrations of monomers showed the chemical composition of the resulting films. Conclusion The presented approach of vapor-phase coating of solid-state structures is important and applicable in many areas of bio-nano interface development. The exposure of coatings to the solutions of different pH showed the stability of the coatings in chemical surroundings. The organic nanocoating of films can be used in bio-implants and many medical devices. PMID:21569579

Porous Organic Nanolayers for Coating of Solid-state Devices

Directory of Open Access Journals (Sweden)

Asghar Waseem

2011-05-01

Full Text Available Abstract Background Highly hydrophobic surfaces can have very low surface energy and such low surface energy biological interfaces can be obtained using fluorinated coatings on surfaces. Deposition of biocompatible organic films on solid-state surfaces is attained with techniques like plasma polymerization, biomineralization and chemical vapor deposition. All these require special equipment or harsh chemicals. This paper presents a simple vapor-phase approach to directly coat solid-state surfaces with biocompatible films without any harsh chemical or plasma treatment. Hydrophilic and hydrophobic monomers were used for reaction and deposition of nanolayer films. The monomers were characterized and showed a very consistent coating of 3D micropore structures. Results The coating showed nano-textured surface morphology which can aid cell growth and provide rich molecular functionalization. The surface properties of the obtained film were regulated by varying monomer concentrations, reaction time and the vacuum pressure in a simple reaction chamber. Films were characterized by contact angle analysis for surface energy and with profilometer to measure the thickness. Fourier Transform Infrared Spectroscopy (FTIR analysis revealed the chemical composition of the coated films. Variations in the FTIR results with respect to different concentrations of monomers showed the chemical composition of the resulting films. Conclusion The presented approach of vapor-phase coating of solid-state structures is important and applicable in many areas of bio-nano interface development. The exposure of coatings to the solutions of different pH showed the stability of the coatings in chemical surroundings. The organic nanocoating of films can be used in bio-implants and many medical devices.

Electrophoretic deposition of sol-gel-derived ceramic coatings

International Nuclear Information System (INIS)

Zhang, Y.; Crooks, R.M.

1992-01-01

In this paper the physical, optical, and chemical characteristics of electrophoretically and dip-coated sol-gel ceramic films are compared. The results indicate that electrophoresis may allow a higher level of control over the chemistry and structure of ceramic coatings than dip-coating techniques. For example, controlled-thickness sol-gel coatings can be prepared by adjusting the deposition time or voltage. Additionally, electrophoretic coatings can be prepared in a four-component alumino-borosilicate sol display interesting optical characteristics. For example, the ellipsometrically-measured refractive indices of electrophoretic coatings are higher than the refractive indices of dip-coated films cast from identical sols, and they are also higher than any of the individual sol components. This result suggests that there are physical and/or chemical differences between films prepared by dip-coating and electrophoresis

Metallic coating of microspheres

International Nuclear Information System (INIS)

Meyer, S.F.

1980-01-01

Extremely smooth, uniform metal coatings of micrometer thicknesses on microscopic glass spheres (microspheres) are often needed as targets for inertial confinement fusion (ICF) experiments. The first part of this paper reviews those methods used successfully to provide metal coated microspheres for ICF targets, including magnetron sputtering, electro- and electroless plating, and chemical vapor pyrolysis. The second part of this paper discusses some of the critical aspects of magnetron sputter coating of microspheres, including substrate requirements, the sticking of microspheres during coating (preventing a uniform coating), and the difficulties in growing the desired dense, smooth, uniform microstructure on continuously moving spherical substrates

Using Fluorescence XANES Measurement to Correct the Content of Hexavalent Chromium in Chromate Conversion Coatings Determined by Diphenyl Carbazide Color Test

International Nuclear Information System (INIS)

Nishino, Junichi; Ofuchi, Hironori; Taniguchi, Yosuke; Honma, Tetsuo; Sekikawa, Toshikazu; Otani, Haruka; Bando, Akio

2007-01-01

The Restriction of the use of certain Hazardous Substances (RoHS) directive will take effect on July 1 of this year. From that date, the use of chromate conversion coatings containing hexavalent chromium will not be permitted. By comparing the concentration of Cr6+ determined by the diphenyl carbazide color test and by fluorescence XANES (X-Ray Absorption Near Edge Structure) measurement, we can correct for the Cr6+ content of the color test. This will enable the use of the diphenyl carbazide color test to check product shipments in compliance with the RoHS directive

Growth of ZnS-coated ZnO nanorod arrays on (1 0 0) silicon substrate by two-step chemical synthesis

International Nuclear Information System (INIS)

Kumarakuru, Haridas; Urgessa, Zelalem N.; Olivier, Ezra J.; Botha, Johannes R.; Venter, Andre; Neethling, Johannes H.

2014-01-01

Highlights: • ZnS coated ZnO nanorods were synthesized using a simple two-step chemical method. • The uniform ZnS coating exhibits a polycrystalline face centered cubic structure. • Initial ZnS deposit exhibits a partial epitaxial relationship with ZnO. • An ion-exchange reaction was deduced for this sulphidation process. • Detailed microscopy results are complemented by room temperature photoluminescence. - Abstract: In this study, ZnS coated ZnO nanorods were synthesized using a simple, cost effective two-step chemical method. A continuous coating of ZnS on a ZnO nanorod, having a uniform thickness, is demonstrated using high resolution transmission electron microscopy, electron energy loss spectroscopy and selected area diffraction (SAD). These core–shell structures can be produced at relatively low temperatures (75 °C) and within relatively short times (3 h). The ZnS coating exhibits a polycrystalline structure with a lattice parameter of 5.35 Å, which is 1.1% smaller than the unstrained cubic zinc-blende structure. The SAD pattern taken at the ZnO–ZnS interface exhibits a partial epitaxial relationship, where (1 0 –1 0) ZnO//(1 1 1) ZnS. Our detailed analysis shows that the ZnS shell comprises two different regions: a ZnS rich inner shell region is produced via the first sulphidation process, followed by a mixture of ZnO and ZnS in the outer shell region during the second treatment. From the detailed microscopy results a growth mechanism is proposed for each step of the sulphidation process. The results are complemented by room temperature photoluminescence spectroscopy. Strong emission from free excitons in ZnO is observed at 3.27 eV before ZnS coating, while a composite band peaking at 2.9 eV is measured after sulphidation. The origin of the latter will be discussed

Growth of ZnS-coated ZnO nanorod arrays on (1 0 0) silicon substrate by two-step chemical synthesis

Energy Technology Data Exchange (ETDEWEB)

Kumarakuru, Haridas, E-mail: haridas.kumarakuru@nmmu.ac.za [Centre for High Resolution Transmission Electron Microscopy (CHRTEM), Department of Physics, P.O.Box 77000, Nelson Mandela Metropolitan University (NMMU), Port Elizabeth 6031 (South Africa); Urgessa, Zelalem N. [Department of Physics, Nelson Mandela Metropolitan University (NMMU), P.O. Box 77000, Port Elizabeth 6031 (South Africa); Olivier, Ezra J. [Centre for High Resolution Transmission Electron Microscopy (CHRTEM), Department of Physics, P.O.Box 77000, Nelson Mandela Metropolitan University (NMMU), Port Elizabeth 6031 (South Africa); Botha, Johannes R.; Venter, Andre [Department of Physics, Nelson Mandela Metropolitan University (NMMU), P.O. Box 77000, Port Elizabeth 6031 (South Africa); Neethling, Johannes H. [Centre for High Resolution Transmission Electron Microscopy (CHRTEM), Department of Physics, P.O.Box 77000, Nelson Mandela Metropolitan University (NMMU), Port Elizabeth 6031 (South Africa); Department of Physics, Nelson Mandela Metropolitan University (NMMU), P.O. Box 77000, Port Elizabeth 6031 (South Africa)

2014-11-05

Highlights: • ZnS coated ZnO nanorods were synthesized using a simple two-step chemical method. • The uniform ZnS coating exhibits a polycrystalline face centered cubic structure. • Initial ZnS deposit exhibits a partial epitaxial relationship with ZnO. • An ion-exchange reaction was deduced for this sulphidation process. • Detailed microscopy results are complemented by room temperature photoluminescence. - Abstract: In this study, ZnS coated ZnO nanorods were synthesized using a simple, cost effective two-step chemical method. A continuous coating of ZnS on a ZnO nanorod, having a uniform thickness, is demonstrated using high resolution transmission electron microscopy, electron energy loss spectroscopy and selected area diffraction (SAD). These core–shell structures can be produced at relatively low temperatures (75 °C) and within relatively short times (3 h). The ZnS coating exhibits a polycrystalline structure with a lattice parameter of 5.35 Å, which is 1.1% smaller than the unstrained cubic zinc-blende structure. The SAD pattern taken at the ZnO–ZnS interface exhibits a partial epitaxial relationship, where (1 0 –1 0) ZnO//(1 1 1) ZnS. Our detailed analysis shows that the ZnS shell comprises two different regions: a ZnS rich inner shell region is produced via the first sulphidation process, followed by a mixture of ZnO and ZnS in the outer shell region during the second treatment. From the detailed microscopy results a growth mechanism is proposed for each step of the sulphidation process. The results are complemented by room temperature photoluminescence spectroscopy. Strong emission from free excitons in ZnO is observed at 3.27 eV before ZnS coating, while a composite band peaking at 2.9 eV is measured after sulphidation. The origin of the latter will be discussed.

Energy conversion & storage program. 1995 annual report

Energy Technology Data Exchange (ETDEWEB)

Cairns, E.J.

1996-06-01

The 1995 annual report discusses laboratory activities in the Energy Conversion and Storage (EC&S) Program. The report is divided into three categories: electrochemistry, chemical applications, and material applications. Research performed in each category during 1995 is described. Specific research topics relate to the development of high-performance rechargeable batteries and fuel cells, the development of high-efficiency thermochemical processes for energy conversion, the characterization of new chemical processes and complex chemical species, and the study and application of novel materials related to energy conversion and transmission. Research projects focus on transport-process principles, chemical kinetics, thermodynamics, separation processes, organic and physical chemistry, novel materials and deposition technologies, and advanced methods of analysis.

Biochemical Conversion Processes of Lignocellulosic Biomass to Fuels and Chemicals - A Review.

Science.gov (United States)

Brethauer, Simone; Studer, Michael H

2015-01-01

Lignocellulosic biomass - such as wood, agricultural residues or dedicated energy crops - is a promising renewable feedstock for production of fuels and chemicals that is available at large scale at low cost without direct competition for food usage. Its biochemical conversion in a sugar platform biorefinery includes three main unit operations that are illustrated in this review: the physico-chemical pretreatment of the biomass, the enzymatic hydrolysis of the carbohydrates to a fermentable sugar stream by cellulases and finally the fermentation of the sugars by suitable microorganisms to the target molecules. Special emphasis in this review is put on the technology, commercial status and future prospects of the production of second-generation fuel ethanol, as this process has received most research and development efforts so far. Despite significant advances, high enzyme costs are still a hurdle for large scale competitive lignocellulosic ethanol production. This could be overcome by a strategy termed 'consolidated bioprocessing' (CBP), where enzyme production, enzymatic hydrolysis and fermentation is integrated in one step - either by utilizing one genetically engineered superior microorganism or by creating an artificial co-culture. Insight is provided on both CBP strategies for the production of ethanol as well as of advanced fuels and commodity chemicals.

Hygroscopicity of mineral dust particles: Roles of chemical mixing state and hygroscopic conversion timescale

Science.gov (United States)

Sullivan, R. C.; Moore, M. J.; Petters, M. D.; Laskin, A.; Roberts, G. C.; Kreidenweis, S. M.; Prather, K. A.

2009-05-01

Our laboratory investigations of mineral dust particle hygroscopicity are motivated by field observations of the atmospheric processing of dust. During ACE-Asia we observed sulphate and nitrate to be strongly segregated from each other in individual aged Asian dust particles. CCN activation curves of pure calcium minerals as proxies for fresh (calcium carbonate) and aged (calcium sulphate, nitrate, chloride) dust indicate that this mixing state would cause a large fraction of aged dust particles to remain poor warm cloud nucleation potential, contrary to previous assumptions. The enrichment of oxalic acid in calcium-rich dust particles could have similar effects due to the formation of insoluble calcium oxalate. Soluble calcium nitrate and chloride reaction products are hygroscopic and will transform mineral dust into excellent CCN. Generating insoluble mineral particles wet by atomization produced particles with much higher hygroscopicity then when resuspended dry. The atomized particles are likely composed of dissolved residuals and do not properly reflect the chemistry of dry mineral powders. Aerosol flow tube experiments were employed to study the conversion of calcium carbonate into calcium nitrate via heterogeneous reaction with nitric acid, with simultaneous measurements of the reacted particles' chemistry and hygroscopicity. The timescale for this hygroscopic conversion was found to occur on the order of a few hours under tropospheric conditions. This implies that the conversion of non-hygroscopic calcite- containing dust into hygroscopic particles will be controlled by the availability of nitric acid, and not by the atmospheric residence time. Results from recent investigations of the effect of secondary coatings on the ice nucleation properties of dust particles will also be presented. The cloud formation potential of aged dust particles depends on both the quantity and form of the secondary species that have reacted or mixed with the dust. These results

Reduced chemical warfare agent sorption in polyurethane-painted surfaces via plasma-enhanced chemical vapor deposition of perfluoroalkanes.

Science.gov (United States)

Gordon, Wesley O; Peterson, Gregory W; Durke, Erin M

2015-04-01

Perfluoralkalation via plasma chemical vapor deposition has been used to improve hydrophobicity of surfaces. We have investigated this technique to improve the resistance of commercial polyurethane coatings to chemicals, such as chemical warfare agents. The reported results indicate the surface treatment minimizes the spread of agent droplets and the sorption of agent into the coating. The improvement in resistance is likely due to reduction of the coating's surface free energy via fluorine incorporation, but may also have contributing effects from surface morphology changes. The data indicates that plasma-based surface modifications may have utility in improving chemical resistance of commercial coatings.

Biomass thermo-conversion. Research trends

International Nuclear Information System (INIS)

Rodriguez Machin, Lizet; Perez Bermudez, Raul; Quintana Perez, Candido Enrique; Ocanna Guevara, Victor Samuel; Duffus Scott, Alejandro

2011-01-01

In this paper is studied the state of the art in order to identify the main trends of the processes of thermo conversion of biomass into fuels and other chemicals. In Cuba, from total supply of biomass, wood is the 19% and sugar cane bagasse and straw the 80%, is why research in the country, should be directed primarily toward these. The methods for energy production from biomass can be group into two classes: thermo-chemical and biological conversion routes. The technology of thermo-chemical conversion includes three subclasses: pyrolysis, gasification, and direct liquefaction. Although pyrolysis is still under development, in the current energy scenario, has received special attention, because can convert directly biomass into solid, liquid and gaseous by thermal decomposition in absence of oxygen. The gasification of biomass is a thermal treatment, where great quantities of gaseous products and small quantities of char and ash are produced. In Cuba, studies of biomass thermo-conversion studies are limited to slow pyrolysis and gasification; but gas fuels, by biomass, are mainly obtained by digestion (biogas). (author)

Aluminium Alloy AA6060 surface treatment with high temperature steam containing chemical additives

DEFF Research Database (Denmark)

Din, Rameez Ud; Tabrizian, Naja; Jellesen, Morten S.

2015-01-01

The steam treatment process was employed to produce a conversion coating on aluminium alloy AA6060. The changes in microstructure and its effect on corrosion resistance properties were investigated. Various concentrations of KMnO4 containing Ce(NO3)3 was injected into the steam and its effect...... on the formation of steam-based conversion coating was evaluated. The use of Mn-Ce into the steam resulted in incorporation of these species into the conversion coating, which resulted in improved corrosion resistance of the alloy substrate....

Tensile test of a silicon microstructure fully coated with submicrometer-thick diamond like carbon film using plasma enhanced chemical vapor deposition method

Science.gov (United States)

Zhang, Wenlei; Uesugi, Akio; Hirai, Yoshikazu; Tsuchiya, Toshiyuki; Tabata, Osamu

2017-06-01

This paper reports the tensile properties of single-crystal silicon (SCS) microstructures fully coated with sub-micrometer thick diamond like carbon (DLC) film using plasma enhanced chemical vapor deposition (PECVD). To minimize the deformations or damages caused by non-uniform coating of DLC, which has high compression residual stress, released SCS specimens with the dimensions of 120 µm long, 4 µm wide, and 5 µm thick were coated from the top and bottom side simultaneously. The thickness of DLC coating is around 150 nm and three different bias voltages were used for deposition. The tensile strength improved from 13.4 to 53.5% with the increasing of negative bias voltage. In addition, the deviation in strength also reduced significantly compared to bare SCS sample.

The perspective effects of various seed coating substances on rice seed variety Khao Dawk Mali 105 storability II: the case study of chemical and biochemical properties.

Science.gov (United States)

Thobunluepop, P; Pan-in, W; Pawelzik, E; Vearasilp, S

2009-04-01

The aim of this study was to investigate the effects of seed coating substances; chemical fungicide (CA) and biological fungicide polymers [chitosan-lignosulphonate polymer (CL) and eugenol incorporated into chitosan-lignosulphonate polymer (E+CL)] on chemical and biochemical changes of rice seeds cv. KDML 105, which have been studied during storage for 12 months. CA significantly affected the rice seed chemical properties and the associated seed deterioration. After 12 months storage, protein content decreased accompanied by declined of lipid content, increased free fatty acids and activated lipoxygenase enzyme. In the case of biological fungicide coated seeds, the antioxidative scavenging enzymes were ascorbate peroxidase and superoxide dismutase and a high antioxidant activity protected them. Moreover, the sugar content was positive correlated with seed germination and vigor. The biological coated seeds were found to maintain high sugar contents inside the seeds, which resulted high seed storability significantly. In contrast, under fungicide stress (CA), those compounds were lost that directly affected seed vigor during storage.

Improvement of conversion efficiency of silicon solar cells using up-conversion molybdate La2Mo2O9:Yb,R (R=Er, Ho) phosphors

Institute of Scientific and Technical Information of China (English)

Yen-Chi Chen; Teng-Ming Chen

2011-01-01

The goal of this work was aimed to improve the power conversion efficiency of single crystalline silicon-based photovoltaic cells by using the solar spectral conversion principle,which employs an up-conversion phosphor to convert a low energy infrared photon to the more energetic visible photons to improve the spectral response.In this study,the surface of multicrystalline silicon solar cells was coated with an up-conversion molybdate phosphor to improve the spectral response of the solar cell in the ncar-infiared spectral range.The short circuit current (Isc),open circuit voltage (Voc),and conversion efficiency (η) of spectral conversion cells were measured.Preliminary experimental results revealed that the light conversion efficiency of a 1.5％-2.7％ increase in Si-based cell was achieved.

Chemical Processing of Nanostructured Coatings

Science.gov (United States)

2000-01-01

in the literature ranging from IR imaging to anti-scratch to smart windows and waveguides. Uhlmann and Towee have taken a survey of the sol-gel...Proteins and enzymes can be encapsulated in silica glass (12), while still retaining their activity. Sol-gel coatings (13,14) of hydroxyapatite should also...Technology, 13, 261-65. 14. Lolpatin, C. M. Pizziloni, V., Alford, T. L., and Lawsaon, T (1998) Hydroxyapatite powders ad thin films prepared by sol

Effects of surface treatment of aluminium alloy 1050 on the adhesion and anticorrosion properties of the epoxy coating

Energy Technology Data Exchange (ETDEWEB)

Sharifi Golru, S., E-mail: samanesharifi@aut.ac.ir [Department of Polymer Engineering and Color Technology, Amirkabir University of Technology, P.O. Box 15875-4413 Tehran (Iran, Islamic Republic of); Attar, M.M., E-mail: attar@aut.ac.ir [Department of Polymer Engineering and Color Technology, Amirkabir University of Technology, P.O. Box 15875-4413 Tehran (Iran, Islamic Republic of); Ramezanzadeh, B. [Department of Surface Coating and Corrosion, Institute for Color Science and Technology, No. 59,Vafamanesh St, Hosainabad Sq, Lavizan, Tehran (Iran, Islamic Republic of)

2015-08-01

Highlights: • Aluminium alloy 1050 was treated by zirconium-based (Zr) conversion coating. • The surface morphology and surface free energy of the samples were obtained. • The adhesion properties of the epoxy coating was studied on the treated samples. • The corrosion resistance of the epoxy coating was enhanced on treated samples. - Abstract: The objective of this work is to investigate the effects of zirconium-based (Zr) conversion coating on the adhesion properties and corrosion resistance of an epoxy/polyamide coating applied on the aluminium alloy 1050 (AA1050). Field emission scanning electron microscope (FE-SEM), energy dispersive X-ray spectrum (EDS), atomic force microscope (AFM) and contact angle measuring device were employed in order to characterize the surface characteristics of the Zr treated AA1050 samples. The epoxy/polyamide coating was applied on the untreated and Zr treated samples. The epoxy coating adhesion to the aluminium substrate was evaluated by pull-off test before and after 30 days immersion in 3.5% w/w NaCl solution. In addition, the electrochemical impedance spectroscopy (EIS) and salt spray tests were employed to characterize the corrosion protection properties of the epoxy coating applied on the AA1050 samples. Results revealed that the surface treatment of AA1050 by zirconium conversion coating resulted in the increase of surface free energy and surface roughness. The dry and recovery (adhesion strength after 30 days immersion in the 3.5 wt% NaCl solution) adhesion strengths of the coatings applied on the Zr treated aluminium samples were greater than untreated sample. In addition, the adhesion loss of the coating applied on the Zr treated aluminium substrate was lower than other samples. Also, the results obtained from EIS and salt spray test clearly revealed that the Zr conversion coating could enhance the corrosion protective performance of the epoxy coating significantly.

Surface modification of reverse osmosis desalination membranes by thin-film coatings deposited by initiated chemical vapor deposition

Energy Technology Data Exchange (ETDEWEB)

Ozaydin-Ince, Gozde, E-mail: gozdeince@sabanciuniv.edu [Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Matin, Asif, E-mail: amatin@mit.edu [Department of Mechanical Engineering, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Khan, Zafarullah, E-mail: zukhan@mit.edu [Department of Mechanical Engineering, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Zaidi, S.M. Javaid, E-mail: zaidismj@kfupm.edu.sa [Department of Mechanical Engineering, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Gleason, Karen K., E-mail: kkgleasn@mit.edu [Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)

2013-07-31

Thin-film polymeric reverse osmosis membranes, due to their high permeation rates and good salt rejection capabilities, are widely used for seawater desalination. However, these membranes are prone to biofouling, which affects their performance and efficiency. In this work, we report a method to modify the membrane surface without damaging the active layer or significantly affecting the performance of the membrane. Amphiphilic copolymer films of hydrophilic hydroxyethylmethacrylate and hydrophobic perfluorodecylacrylate (PFA) were synthesized and deposited on commercial RO membranes using an initiated chemical vapor deposition technique which is a polymer deposition technique that involves free-radical polymerization initiated by gas-phase radicals. Relevant surface characteristics such as hydrophilicity and roughness could be systematically controlled by varying the polymer chemistry. Increasing the hydrophobic PFA content in the films leads to an increase in the surface roughness and hydrophobicity. Furthermore, the surface morphology studies performed using the atomic force microscopy show that as the thickness of the coating increases average surface roughness increases. Using this knowledge, the coating thickness and chemistry were optimized to achieve high permeate flux and to reduce cell attachment. Results of the static bacterial adhesion tests show that the attachment of bacterial cells is significantly reduced on the coated membranes. - Highlights: • Thin films are deposited on reverse osmosis membranes. • Amphiphilic thin films are resistant to protein attachment. • The permeation performance of the membranes is not affected by the coating. • The thin film coatings delayed the biofouling.

Energy Conversion and Storage Program

Energy Technology Data Exchange (ETDEWEB)

Cairns, E.J.

1992-03-01

The Energy Conversion and Storage Program applies chemistry and materials science principles to solve problems in (1) production of new synthetic fuels, (2) development of high-performance rechargeable batteries and fuel cells, (3) development of advanced thermochemical processes for energy conversion, (4) characterization of complex chemical processes, and (5) application of novel materials for energy conversion and transmission. Projects focus on transport-process principles, chemical kinetics, thermodynamics, separation processes, organic and physical chemistry, novel materials, and advanced methods of analysis. Electrochemistry research aims to develop advanced power systems for electric vehicle and stationary energy storage applications. Topics include identification of new electrochemical couples for advanced rechargeable batteries, improvements in battery and fuel-cell materials, and the establishment of engineering principles applicable to electrochemical energy storage and conversion. Chemical Applications research includes topics such as separations, catalysis, fuels, and chemical analyses. Included in this program area are projects to develop improved, energy-efficient methods for processing waste streams from synfuel plants and coal gasifiers. Other research projects seek to identify and characterize the constituents of liquid fuel-system streams and to devise energy-efficient means for their separation. Materials Applications research includes the evaluation of the properties of advanced materials, as well as the development of novel preparation techniques. For example, the use of advanced techniques, such as sputtering and laser ablation, are being used to produce high-temperature superconducting films.

Conversion factors from counts to chemical ratios for the EURITRACK tagged neutron inspection system

International Nuclear Information System (INIS)

El Kanawati, W.; Perot, B.; Carasco, C.; Eleon, C.; Valkovic, V.; Sudac, D.; Obhodas, J.

2011-01-01

The EURopean Illicit TRAfficking Countermeasures Kit (EURITRACK) uses 14 MeV neutrons produced by the 3 H(d,n) 4 H fusion reaction to detect explosives and narcotics in cargo containers. Reactions induced by fast neutrons produce gamma rays, which are detected in coincidence with the associated alpha particle to determine the neutron direction. In addition, the neutron path length is obtained from a time-of-flight measurement, thus allowing the origin of the gamma rays inside the container to be determined. Information concerning the chemical composition of the target material is obtained from the analysis of the energy spectrum. The carbon, oxygen, and nitrogen relative count contributions must be converted to chemical proportions to distinguish illicit and benign organic materials. An extensive set of conversion factors based on Monte Carlo numerical simulations has been calculated, taking into account neutron slowing down and photon attenuation in the cargo materials. An experimental validation of the method is presented by comparing the measured chemical fractions of known materials, in the form of bare samples or hidden in a cargo container, to their real chemical composition. Examples of application to real cargo containers are also reported, as well as simulated data with explosives and illicit drugs.

Conversion factors from counts to chemical ratios for the EURITRACK tagged neutron inspection system

Energy Technology Data Exchange (ETDEWEB)

El Kanawati, W. [CEA, DEN, Cadarache, Nuclear Measurement Laboratory, F-13108 Saint-Paul-lez-Durance (France); Perot, B., E-mail: bertrand.perot@cea.fr [CEA, DEN, Cadarache, Nuclear Measurement Laboratory, F-13108 Saint-Paul-lez-Durance (France); Carasco, C.; Eleon, C. [CEA, DEN, Cadarache, Nuclear Measurement Laboratory, F-13108 Saint-Paul-lez-Durance (France); Valkovic, V. [A.C.T.d.o.o., Prilesje 4, 10000 Zagreb (Croatia); Sudac, D.; Obhodas, J. [Ruder Boskovic Institute, Bijenicka c. 54, 10000 Zagreb (Croatia)

2011-10-21

The EURopean Illicit TRAfficking Countermeasures Kit (EURITRACK) uses 14 MeV neutrons produced by the {sup 3}H(d,n){sup 4}H fusion reaction to detect explosives and narcotics in cargo containers. Reactions induced by fast neutrons produce gamma rays, which are detected in coincidence with the associated alpha particle to determine the neutron direction. In addition, the neutron path length is obtained from a time-of-flight measurement, thus allowing the origin of the gamma rays inside the container to be determined. Information concerning the chemical composition of the target material is obtained from the analysis of the energy spectrum. The carbon, oxygen, and nitrogen relative count contributions must be converted to chemical proportions to distinguish illicit and benign organic materials. An extensive set of conversion factors based on Monte Carlo numerical simulations has been calculated, taking into account neutron slowing down and photon attenuation in the cargo materials. An experimental validation of the method is presented by comparing the measured chemical fractions of known materials, in the form of bare samples or hidden in a cargo container, to their real chemical composition. Examples of application to real cargo containers are also reported, as well as simulated data with explosives and illicit drugs.

Functionalization of PDMS modified and plasma activated two-component polyurethane coatings by surface attachment of enzymes

International Nuclear Information System (INIS)

Kreider, Alexej; Richter, Katharina; Sell, Stephan; Fenske, Mandus; Tornow, Christian; Stenzel, Volkmar; Grunwald, Ingo

2013-01-01

This article describes a new strategy for coupling the enzyme horseradish peroxidase to a two-component polyurethane (2C-PUR) coating. A stable polymer conjugate was achieved by combining the enzyme and the 2C-PUR coating which was modified with poly(dimethylsiloxane) (PDMS), located at the surface. An atmospheric pressure plasma jet system was used to convert alkyl groups from the PDMS into polar silanol functionalities. This conversion was proven by X-ray photoelectron spectroscopy and dynamic contact angle measurements. In addition, the stability of the activated 2C-PUR surface containing silanol groups was determined by measuring the contact angle as a function of time. Compared to the non-modified 2C-PUR systems the one with PDMS displayed a higher stability over a time period over 28 h. In a silanization process the coating was treated with (3-aminopropyl) trimethoxysilane and the enzyme was subsequently immobilized to the coating via the cross linker glutaraldehyde to receive new biomimetic catalytic/enzymatic functions. The chemical immobilization (chemisorption) of the enzyme to the surface showed statistically significant higher biological activity as compared to references samples without using a cross linker (physisorption). The presented technique offers the opportunity to design new and smart multifunctional surface coatings which employ biomimetic capabilities.

Functionalization of PDMS modified and plasma activated two-component polyurethane coatings by surface attachment of enzymes

Energy Technology Data Exchange (ETDEWEB)

Kreider, Alexej; Richter, Katharina; Sell, Stephan; Fenske, Mandus; Tornow, Christian; Stenzel, Volkmar [Fraunhofer Institute for Manufacturing Technology and Advanced Materials - IFAM, Wiener Strasse 12, 28359 Bremen (Germany); Grunwald, Ingo, E-mail: ingo.grunwald@ifam.fraunhofer.de [Fraunhofer Institute for Manufacturing Technology and Advanced Materials - IFAM, Wiener Strasse 12, 28359 Bremen (Germany)

2013-05-15

This article describes a new strategy for coupling the enzyme horseradish peroxidase to a two-component polyurethane (2C-PUR) coating. A stable polymer conjugate was achieved by combining the enzyme and the 2C-PUR coating which was modified with poly(dimethylsiloxane) (PDMS), located at the surface. An atmospheric pressure plasma jet system was used to convert alkyl groups from the PDMS into polar silanol functionalities. This conversion was proven by X-ray photoelectron spectroscopy and dynamic contact angle measurements. In addition, the stability of the activated 2C-PUR surface containing silanol groups was determined by measuring the contact angle as a function of time. Compared to the non-modified 2C-PUR systems the one with PDMS displayed a higher stability over a time period over 28 h. In a silanization process the coating was treated with (3-aminopropyl) trimethoxysilane and the enzyme was subsequently immobilized to the coating via the cross linker glutaraldehyde to receive new biomimetic catalytic/enzymatic functions. The chemical immobilization (chemisorption) of the enzyme to the surface showed statistically significant higher biological activity as compared to references samples without using a cross linker (physisorption). The presented technique offers the opportunity to design new and smart multifunctional surface coatings which employ biomimetic capabilities.

Protonated graphitic carbon nitride coated metal-organic frameworks with enhanced visible-light photocatalytic activity for contaminants degradation

Science.gov (United States)

Huang, Jie; Zhang, Xibiao; Song, Haiyan; Chen, Chunxia; Han, Fuqin; Wen, Congcong

2018-05-01

Most of the reported composites of g-C3N4/metal-organic frameworks (MOFs) were obtained via exfoliation of g-C3N4 and wrapping the nanosheets on MOFs with weak interaction. In this work, chemical protonation of g-C3N4 and dip-coating was adopted as a feasible pathway to achieve the real combination of g-C3N4 derivatives with a familiar MOF material MIL-100(Fe). Structural, chemical and photophysical properties of the novel hybrid photocatalysts were characterized and compared to those of the parent materials. It was verified that the protonated g-C3N4 species of appropriate content were uniformly coated along the frameworks of MIL-100(Fe) with strong interaction. The optimal materials maintained the intact framework structure, surface property and porosity of MIL-100(Fe), as well as the inherent structural units and physicochemical properties of C3N4. In comparison to the parent materials, the protonated g-C3N4 coated MIL-100(Fe) materials exhibited enhanced photocatalytic activity in degradation of rhodamine B or methylene blue dye, as well as in oxidative denitrogenation for pyridine by molecular oxygen under visible light. Introduction of protonated g-C3N4 on MOFs improved the adsorption ability for contaminant molecules. Furthermore, coating effect provided a platform for rapid photoexcited electrons transfer and superior separation of photogenerated electron-hole pairs. Photocatalytic conversion of the three contaminants followed different mechanisms.

Bulletin of Materials Science | Indian Academy of Sciences

Indian Academy of Sciences (India)

Cerium–vanadium (Ce–V) conversion coating was proposed as a new pretreatment for application of electroless Ni–P coating on AM60B magnesium alloy to replace the traditional chromium oxide pretreatment. Morphology and chemical composition of the conversion coating were investigated. The subsequent Ni–P ...

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

International Nuclear Information System (INIS)

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

2010-01-01

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

Chemical conversion of cisplatin and carboplatin with histidine in a model protein crystallized under sodium iodide conditions

Energy Technology Data Exchange (ETDEWEB)

Tanley, Simon W. M.; Helliwell, John R., E-mail: john.helliwell@manchester.ac.uk [University of Manchester, Brunswick Street, Manchester M13 9PL (United Kingdom)

2014-08-29

Crystals of HEWL with cisplatin and HEWL with carboplatin grown in sodium iodide conditions both show a partial chemical transformation of cisplatin or carboplatin to a transiodoplatin (PtI{sub 2}X{sub 2}) form. The binding is only at the N{sup δ} atom of His15. A further Pt species (PtI{sub 3}X) is also seen, in both cases bound in a crevice between symmetry-related protein molecules. Cisplatin and carboplatin are platinum anticancer agents that are used to treat a variety of cancers. Previous X-ray crystallographic studies of carboplatin binding to histidine in hen egg-white lysozyme (HEWL) showed a partial chemical conversion of carboplatin to cisplatin owing to the high sodium chloride concentration used in the crystallization conditions. Also, the co-crystallization of HEWL with carboplatin in sodium bromide conditions resulted in the partial conversion of carboplatin to the transbromoplatin form, with a portion of the cyclobutanedicarboxylate (CBDC) moiety still present. The results of the co-crystallization of HEWL with cisplatin or carboplatin in sodium iodide conditions are now reported in order to determine whether the cisplatin and carboplatin converted to the iodo form, and whether this took place in a similar way to the partial conversion of carboplatin to cisplatin in NaCl conditions or to transbromoplatin in NaBr conditions as seen previously. It is reported here that a partial chemical transformation has taken place to a transplatin form for both ligands. The NaI-grown crystals belonged to the monoclinic space group P2{sub 1} with two molecules in the asymmetric unit. The chemically transformed cisplatin and carboplatin bind to both His15 residues, i.e. in each asymmetric unit. The binding is only at the N{sup δ} atom of His15. A third platinum species is also seen in both conditions bound in a crevice between symmetry-related molecules. Here, the platinum is bound to three I atoms identified based on their anomalous difference electron densities

The Role of interfacial layers on the performance of an epoxy / polyester powder coated Aluminium Alloy

International Nuclear Information System (INIS)

Mirabedini, M.; Moradian, S.; Scanteburg, D.; Thonpson, G.E.

2002-01-01

The influence of polyacrylic acid and a blend of polyacrylic acid with hexa fluorozirconic acid treatments on the performance of an epoxy/polyester powder coating on a 1050 Al substrate has been studied and compared to the performance of the same system using a so-called chromate/phosphate conversion coating. The chemical interactions between pretreatments and Al substrates were examined using FTIR spectroscopy and various accelerated test methods were also employed. Two mechanical adhesion measurement methods were used under wet and dry conditions, namely a vertical pull-off test in the dry state and the tape test under dry conditions. The water permeation of the differently pretreated powder coated samples was studied using a capacitance measurement method. FTIR results showed two modes of interaction; namely ionic and complex formation between COO - and Al 3+ Various experiments revealed that polyacrylic acid improved only the dry adhesion but as a standing alone treatment it did not provide an overall improvement in anti-corrosive performance. The water uptake measurements proved that pretreatment does not considerably affect the properties of the coatings during water permeation stage. The use of various techniques revealed that relatively good performance of powder coating is due to a high ohmic resistance of the coating prior to and after saturation with water, reasonably low water solubility and good adhesion to the substrate

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.

Biomass valorisation by staged degasification A new pyrolysis-based thermochemical conversion option to produce value-added chemicals from lignocellulosic biomass

NARCIS (Netherlands)

de Wild, P. J.; den Uil, H.; Reith, J. H.; Kiel, J. H. A.; Heeres, H. J.

Pyrolysis of lignocellulosic biomass leads to an array Of useful solid, liquid and gaseous products. Staged degasification is a pyrolysis-based conversion route to generate value-added chemicals from biomass. Because of different thermal stabilities of the main biomass constituents hemicellulose.

Conversion of zircaloy to a massive chemically inert form

International Nuclear Information System (INIS)

Atkinson, A.; Kearsey, H.A.; Knibbs, R.H.; Mercer, A.C.; Nickerson, A.K.; Pearson, D.; Sambell, R.A.J.; Taylor, R.I.

1985-01-01

The report covers work carried out in the period July 1980 - December 1982 on the development and assessment of an aqueous route for the conversion of Zircaloy fuel element cladding to a stable oxide form and on alternative methods for incorporating the oxide into monolithic waste forms suitable for long-term storage and disposal. The work included two aspects, preliminary process development studies aimed at demonstrating the key steps in the process, and studies on the alternative immobilization techniques and the properties of the resulting waste forms. Experimental studies have shown that the ''hydrous zirconium oxide'' (with a residual fluoride content), following calcination at about 500 0 C, can be hot-pressed at 800-1000 0 C and 22.5 MPa to a high density ceramic waste form with good capacity for the incorporation of active species, such as U 4+ and Sr 2+ , and high leach resistance. Parallel studies have been carried out on the incorporation of the washed ''hydrous zirconium oxide'' in a range of cement matrices. A preliminary chemical engineering assessment of the overall process has been made and flowsheets for a plant to convert 250 kg Zircaloy/day have been prepared

CONVERSION OF LIGNOCELLULOSIC MATERIAL TO CHEMICALS AND FUELS; TOPICAL

International Nuclear Information System (INIS)

Edwin S. Olson

2001-01-01

A direct conversion of cellulosic wastes, including resin-bonded furniture and building waste, to levulinate esters is being investigated with the view to producing fuels, solvents, and chemical intermediates as well as other useful by-products in an inexpensive process. The acid-catalyzed reaction of cellulosic materials with ethanol or methanol at 200 C gives good yields of levulinate and formate esters, as well as useful by-products, such as a solid residue (charcoal) and a resinous lignin residue. An initial plant design showed reasonable rates of return for production of purified ethyl levulinate and by-products. In this project, investigations have been performed to identify and develop reactions that utilize esters of levulinic acid produced during the acid-catalyzed ethanolysis reaction. We wish to develop uses for levulinate esters that allow their marketing at prices comparable to inexpensive polymer intermediates. These prices will allow a sufficient rate of return to justify building plants for utilizing the waste lignocellulosics. If need is demonstrated for purified levulinate, the initial plant design work may be adequate, at least until further pilot-scale work on the process is performed

Simultaneous multilayer formation of the polymer solar cell stack using roll-to-roll double slot-die coating from water

DEFF Research Database (Denmark)

Larsen-Olsen, Thue Trofod; Andreasen, Birgitta; Andersen, Thomas Rieks

2012-01-01

zinc oxide that was processed by single slot-die coating from water. The active layer comprised poly-3-hexylthiophene:Phenyl-C61-butyric acid methyl ester (P3HT:PCBM) as a dispersion of nanoparticles with a radius of 46 nm in water characterized using small-angle X-ray scattering (SAXS), transmission...... electron microscopy (TEM), and atomic force microscopy (AFM). The HTL was a dispersion of poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) in water. The films were analyzed using time-of-flight secondary ion mass spectrometry (TOF-SIMS) as chemical probe and X-ray reflectometry......), fill factor (FF), and power conversion efficiency (PCE) of 0.24 V, 0.5 mA cm−2, 25%, and 0.03%, respectively, for the best double slot-die coated cell. A single slot-die coated cell using the same aqueous inks and device architecture yielded a Voc, Jsc, FF, and PCE of 0.45 V, 1.95 mA cm−2, 33.1%, and 0...

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.

Nanostructured Metal Oxide Coatings for Electrochemical Energy Conversion and Storage Electrodes

Science.gov (United States)

Cordova, Isvar Abraxas

The realization of an energy future based on safe, clean, sustainable, and economically viable technologies is one of the grand challenges facing modern society. Electrochemical energy technologies underpin the potential success of this effort to divert energy sources away from fossil fuels, whether one considers alternative energy conversion strategies through photoelectrochemical (PEC) production of chemical fuels or fuel cells run with sustainable hydrogen, or energy storage strategies, such as in batteries and supercapacitors. This dissertation builds on recent advances in nanomaterials design, synthesis, and characterization to develop novel electrodes that can electrochemically convert and store energy. Chapter 2 of this dissertation focuses on refining the properties of TiO2-based PEC water-splitting photoanodes used for the direct electrochemical conversion of solar energy into hydrogen fuel. The approach utilized atomic layer deposition (ALD); a growth process uniquely suited for the conformal and uniform deposition of thin films with angstrom-level thickness precision. ALD's thickness control enabled a better understanding of how the effects of nitrogen doping via NH3 annealing treatments, used to reduce TiO2's bandgap, can have a strong dependence on TiO2's thickness and crystalline quality. In addition, it was found that some of the negative effects on the PEC performance typically associated with N-doped TiO2 could be mitigated if the NH 3-annealing was directly preceded by an air-annealing step, especially for ultrathin (i.e., transparent electrode based on a network of solution-processed Cu/Ni cores/shell nanowires (NWs) were activated by electrochemically converting the Ni metal shell into Ni(OH)2. Furthermore, an adjustment of the molar percentage of Ni plated onto the Cu NWs was found to result in a tradeoff between capacitance, transmittance, and stability of the resulting nickel hydroxide-based electrode. The nominal area capacitance and power

A new and efficient Solid Phase Microextraction approach for analysis of high fat content food samples using a matrix-compatible coating.

Science.gov (United States)

De Grazia, Selenia; Gionfriddo, Emanuela; Pawliszyn, Janusz

2017-05-15

The current work presents the optimization of a protocol enabling direct extraction of avocado samples by a new Solid Phase Microextraction matrix compatible coating. In order to further extend the coating life time, pre-desorption and post-desorption washing steps were optimized for solvent type, time, and degree of agitation employed. Using optimized conditions, lifetime profiles of the coating related to extraction of a group of analytes bearing different physical-chemical properties were obtained. Over 80 successive extractions were carried out to establish coating efficiency using PDMS/DVB 65µm commercial coating in comparison with the PDMS/DVB/PDMS. The PDMS/DVB coating was more prone to irreversible matrix attachment on its surface, with consequent reduction of its extractive performance after 80 consecutive extractions. Conversely, the PDMS/DVB/PDMS coating showed enhanced inertness towards matrix fouling due to its outer smooth PDMS layer. This work represents the first step towards the development of robust SPME methods for quantification of contaminants in avocado as well as other fatty-based matrices, with minimal sample pre-treatment prior to extraction. In addition, an evaluation of matrix components attachment on the coating surface and related artifacts created by desorption of the coating at high temperatures in the GC-injector port, has been performed by GCxGC-ToF/MS. Copyright © 2017 Elsevier B.V. All rights reserved.

Mineralogical conversion of asbestos containing materials

International Nuclear Information System (INIS)

Pulsford, S.K.; Foltz, A.D.; Ek, R.B.

1996-01-01

The principal objective of the Technical Task Plan (TTP) is to demonstrate a thermal-chemical mineralogical asbestos conversion unit at the Hanford Site, which converts non-radiological asbestos containing materials (ACMs) into an asbestos-free material. The permanent thermal-chemical mineralogical conversion of ACMs to a non-toxic, non-hazardous, potentially marketable end product should not only significantly reduce the waste stream volumes but terminate the open-quotes cradle to graveclose quotes ownership liabilities

Mechanical matching and microstructural evolution at the coating/substrate interfaces of cold-sprayed Ni, Al coatings

International Nuclear Information System (INIS)

Lee, H.; Lee, S.; Shin, H.; Ko, K.

2009-01-01

The effect of mechanical hard/soft matching of raw powder and substrate in the cold gas dynamic spraying process (CDSP) on the formation of intermetallic compounds was examined. Instead of pre-alloyed materials, pure Al and Ni were selected as a soft and a hard material, respectively, and post-annealing was used for compound formation. Most of the aluminide layers were observed in the coated layer, but not in the substrate, along with the entire original interface for both Al coating on a Ni substrate and vice versa. Thickening of the compound layer depended mainly on the creation of defects during spraying and intrinsic diffusivity of atoms moving toward the coating side. When Ni was coated, the compound layer was made thicker by fast diffusion of Al, while the thickness was limited in soft Al coating on hard Ni substrate. However, the composition of the compound can be affected by relative transfer of diffusing atoms toward both the coating and the substrate. So, for Ni coating on an Al substrate, most of the intermetallic compound formed was Ni-rich and conversion of the Al-rich compound was observed after post-annealing above 500 deg. C.

Thermal barrier coatings: Coating methods, performance, and heat engine applications. (Latest citations from the EI Compendex*plus database). Published Search

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-02-01

The bibliography contains citations concerning conference proceedings on coating methods, performance evaluations, and applications of thermal barrier coatings as protective coatings for heat engine components against high temperature corrosions and chemical erosions. The developments of thermal barrier coating techniques for high performance and reliable gas turbines, diesel engines, jet engines, and internal combustion engines are presented. Topics include plasma sprayed coating methods, yttria stabilized zirconia coatings, coating life models, coating failure and durability, thermal shock and cycling, and acoustic emission analysis of coatings. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

Thermal barrier coatings: Coating methods, performance, and heat engine applications. (Latest citations from the EI Compendex*plus database). Published Search

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-11-01

The bibliography contains citations concerning conference proceedings on coating methods, performance evaluations, and applications of thermal barrier coatings as protective coatings for heat engine components against high temperature corrosions and chemical erosions. The developments of thermal barrier coating techniques for high performance and reliable gas turbines, diesel engines, jet engines, and internal combustion engines are presented. Topics include plasma sprayed coating methods, yttria stabilized zirconia coatings, coating life models, coating failure and durability, thermal shock and cycling, and acoustic emission analysis of coatings. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

Heat-resistant hydrophobic-oleophobic coatings

OpenAIRE

Uyanik, Mehmet; Arpac, Ertugrul; Schmidt, Helmut K.; Akarsu, Murat; Sayilkan, Funda; Sayilkan, Hikmet

2006-01-01

Thermally and chemically durable hydrophobic oleophobic coatings, containing different ceramic particles such as SiO2, SiC, Al 2O3, which can be alternative instead of Teflon, have been developed and applied on the aluminum substrates by spin-coating method. Polyimides, which are high-thermal resistant heteroaromatic polymers, were synthesized, and fluor oligomers were added to these polymers to obtain hydrophobic-oleophobic properties. After coating, Al surface was subjected to Taber-abrasio...

Determination of the DBTT of Aluminide Coatings and its Influence on the Mechanical Behavior of Coated Specimens

Energy Technology Data Exchange (ETDEWEB)

Dryepondt, Sebastien N [ORNL; Pint, Bruce A [ORNL

2010-01-01

The ductility of various coatings deposited by chemical vapor deposition, pack cementation and slurry processes on Fe- and Ni-based alloys was characterized by indentation at room temperature. A hot indentation apparatus has also been developed to more rapidly determine the ductile to brittle transition temperature of coated specimens. Creep testing has been conducted on bare and coated alloy 230 (NiCrW) specimens at 800 C with a significant decrease in creep life observed. Based on the observed failure of coated 230 specimens, the impact of coating ductility on substrate creep properties is discussed.

Doctor Blade-Coated Polymer Solar Cells

KAUST Repository

Cho, Nam Chul; Kim, Jong H.

2016-01-01

In this work, we report polymer solar cells based on blade-coated P3HT:PC71BM and PBDTTT-EFT:PC71BM bulk heterojunction photoactive layers. Enhanced power conversion efficiency of 2.75 (conventional structure) and 3.03% (inverted structure

Residual stress in thick low-pressure chemical-vapor deposited polycrystalline SiC coatings on Si substrates

Science.gov (United States)

Choi, D.; Shinavski, R. J.; Steffier, W. S.; Spearing, S. M.

2005-04-01

Residual stress in thick coatings of polycrystalline chemical-vapor deposited SiC on Si substrates is a key variable that must be controlled if SiC is to be used in microelectromechanical systems. Studies have been conducted to characterize the residual stress level as a function of deposition temperature, Si wafer and SiC coating thickness, and the ratios of methyltrichlorosilane to hydrogen and hydrogen chloride. Wafer curvature was used to monitor residual stress in combination with a laminated plate analysis. Compressive intrinsic (growth) stresses were measured with magnitudes in the range of 200-300MPa; however, these can be balanced with the tensile stress due to the thermal-expansion mismatch to leave near-zero stress at room temperature. The magnitude of the compressive intrinsic stress is consistent with previously reported values of surface stress in combination with the competition between grain-boundary energy and elastic strain energy.

All-chemical YBa2Cu3O7 coated conductors on IBAD-YSZ stainless steel substrates

International Nuclear Information System (INIS)

Pomar, A; Cavallaro, A; Coll, M; Gazquez, J; Palau, A; Sandiumenge, F; Puig, T; Obradors, X; Freyhardt, H C

2006-01-01

We report on the fabrication of all-chemical YBa 2 Cu 3 O 7 coated conductors on IBAD-YSZ (IBAD stands for ion beam assisted deposition; YSZ is yttrium stabilized zirconia) stainless steel substrates. YBCO films were grown by the trifluoroacetates route on top of CeO 2 buffer layers made by metal-organic decomposition. The achievement of atomically flat CeO 2 surfaces is found to be a key factor for obtaining clean interfaces with YBCO and high performance. Coated conductors with percolative critical currents of J c GB (65 K) = 1.8 MA cm -2 were achieved. The determination of the intra-grain critical current J c G from inductive measurements suggests that the limiting factor for J c GB is the YBCO in-plane texture, which is already of higher quality than that of the IBAD-YSZ cap layer. (rapid communication)

Low temperature radio-chemical energy conversion processes

International Nuclear Information System (INIS)

Gomberg, H.J.

1986-01-01

This patent describes a radio-chemical method of converting radiated energy into chemical energy form comprising the steps of: (a) establishing a starting chemical compound in the liquid phase that chemically reacts endothermically to radiation and heat energy to produce a gaseous and a solid constituent of the compound, (b) irradiating the compound in its liquid phase free of solvents to chemically release therefrom in response to the radiation the gaseous and solid constituents, (c) physically separating the solid and gaseous phase constituents from the liquid, and (d) chemically processing the constituents to recover therefrom energy stored therein by the irradiation step (b)

Facile Synthesis of Photofunctional Nanolayer Coatings on Titanium Substrates

Directory of Open Access Journals (Sweden)

Kyong-Hoon Choi

2016-01-01

Full Text Available We developed a two-step chemical bonding process using photosensitizer molecules to fabricate photofunctional nanolayer coatings on hematoporphyrin- (HP- coated Ti substrates. In the first step, 3-aminopropyltriethoxysilane was covalently functionalized onto the surface of the Ti substrates to provide heterogeneous sites for immobilizing the HP molecules. Then, HP molecules with carboxyl groups were chemically attached to the amine-terminated nanolayer coatings via a carbodiimide coupling reaction. The microstructure and elemental and phase composition of the HP-coated Ti substrates were investigated using field-emission scanning electron microscopy and energy-dispersive X-ray spectrometry. The photophysical properties of the photofunctional nanolayer coatings were confirmed using reflectance ultraviolet-visible absorption and emission spectrophotometry. The singlet oxygen generation efficiency of the photofunctional nanolayer coatings was determined using the decomposition reaction of 1,3-diphenylisobenzofuran. The HP-coated Ti substrates exhibited good biocompatibility without any cytotoxicity, and these nanolayer coatings generated singlet oxygen, which can kill microorganisms using only visible light.

Laser-accelerated proton conversion efficiency thickness scaling

International Nuclear Information System (INIS)

Hey, D. S.; Foord, M. E.; Key, M. H.; LePape, S. L.; Mackinnon, A. J.; Patel, P. K.; Ping, Y.; Akli, K. U.; Stephens, R. B.; Bartal, T.; Beg, F. N.; Fedosejevs, R.; Friesen, H.; Tiedje, H. F.; Tsui, Y. Y.

2009-01-01

The conversion efficiency from laser energy into proton kinetic energy is measured with the 0.6 ps, 9x10 19 W/cm 2 Titan laser at the Jupiter Laser Facility as a function of target thickness in Au foils. For targets thicker than 20 μm, the conversion efficiency scales approximately as 1/L, where L is the target thickness. This is explained by the domination of hot electron collisional losses over adiabatic cooling. In thinner targets, the two effects become comparable, causing the conversion efficiency to scale weaker than 1/L; the measured conversion efficiency is constant within the scatter in the data for targets between 5 and 15 μm, with a peak conversion efficiency of 4% into protons with energy greater than 3 MeV. Depletion of the hydrocarbon contaminant layer is eliminated as an explanation for this plateau by using targets coated with 200 nm of ErH 3 on the rear surface. The proton acceleration is modeled with the hybrid-particle in cell code LSP, which reproduced the conversion efficiency scaling observed in the data.

Replacement of traditional seawater-soluble pigments by starch and hydrolytic enzymes in polishing antifouling coatings

DEFF Research Database (Denmark)

Olsen, Søren Martin; Pedersen, L. T.; Dam-Johansen, Kim

2010-01-01

The use of starch and hydrolytic enzymes as replacement for traditional polishing pigments (e.g., Cu2O and ZnO) in antifouling coatings has been investigated. The enzymes facilitate a slow conversion of water-insoluble starch into water-soluble glucose, and dissolution of glucose causes the devel......The use of starch and hydrolytic enzymes as replacement for traditional polishing pigments (e.g., Cu2O and ZnO) in antifouling coatings has been investigated. The enzymes facilitate a slow conversion of water-insoluble starch into water-soluble glucose, and dissolution of glucose causes...... the development of a leached (porous) layer in the wetted, outermost part of the coating. Subsequent water-binder interaction at the pore walls gives rise to polishing, in a manner similar to that of conventional antifouling coatings. Different starch types have been evaluated and classified as potential coating...

Aluminum Oxide Formation On Fecral Catalyst Support By Electro-Chemical Coating

Directory of Open Access Journals (Sweden)

Yang H.S.

2015-06-01

Full Text Available FeCrAl is comprised essentially of Fe, Cr, Al and generally considered as metallic substrates for catalyst support because of its advantage in the high-temperature corrosion resistance, high mechanical strength, and ductility. Oxidation film and its adhesion on FeCrAl surface with aluminum are important for catalyst life. Therefore various appropriate surface treatments such as thermal oxidation, Sol, PVD, CVD has studied. In this research, PEO (plasma electrolytic oxidation process was applied to form the aluminum oxide on FeCrAl surface, and the formed oxide particle according to process conditions such as electric energy and oxidation time were investigated. Microstructure and aluminum oxide particle on FeCrAl surface after PEO process was observed by FE-SEM and EDS with element mapping analysis. The study presents possibility of aluminum oxide formation by electro-chemical coating process without any pretreatment of FeCrAl.

Lipids as renewable resources: current state of chemical and biotechnological conversion and diversification.

Science.gov (United States)

Metzger, J O; Bornscheuer, U

2006-06-01

Oils and fats are the most important renewable raw materials of the chemical industry. They make available fatty acids in such purity that they may be used for chemical conversions and for the synthesis of chemically pure compounds. Oleic acid (1) from "new sunflower," linoleic acid (2) from soybean, linolenic acid (3) from linseed, erucic acid (4) from rape seed, and ricinoleic acid (5) from castor oil are most important for chemical transformations offering in addition to the carboxy group one or more C-C-double bonds. New plant oils containing fatty acids with new and interesting functionalities such as petroselinic acid (6) from Coriandrum sativum, calendic acid (7) from Calendula officinalis, alpha-eleostearic acid (8) from tung oil, santalbic acid (9) from Santalum album (Linn.), and vernolic acid (10) from Vernonia galamensis are becoming industrially available. The basic oleochemicals are free fatty acids, methyl esters, fatty alcohols, and fatty amines as well as glycerol as a by-product. Their interesting new industrial applications are the usage as environmentally friendly industrial fluids and lubricants, insulating fluid for electric utilities such as transformers and additive to asphalt. Modern methods of synthetic organic chemistry including enzymatic and microbial transformations were applied extensively to fatty compounds for the selective functionalization of the alkyl chain. Syntheses of long-chain diacids, omega-hydroxy fatty acids, and omega-unsaturated fatty acids as base chemicals derived from vegetable oils were developed. Interesting applications were opened by the epoxidation of C-C-double bonds giving the possibility of photochemically initiated cationic curing and access to polyetherpolyols. Enantiomerically pure fatty acids as part of the chiral pool of nature can be used for the synthesis of nonracemic building blocks.

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.)

Structural and electrochemical behavior of sol-gel ZrO2 ceramic film on chemically pre-treated AZ91D magnesium alloy

International Nuclear Information System (INIS)

Li Qing; Chen Bo; Xu Shuqiang; Gao Hui; Zhang Liang; Liu Chao

2009-01-01

In the present investigation sol-gel-based ZrO 2 ceramic film was obtained using zirconium acetate as the precursor material. The film was deposited on AZ91D magnesium alloy by a dip-coating technique. An uniform stannate conversion coating as chemical pretreatment was employed as an intermediate layer prior to deposition of the ZrO 2 film in order to provide advantage for the formation of sol-gel-based ZrO 2 layer. The corrosion properties, structure, composition and morphology of these coatings on AZ91D magnesium alloy were studied by potentiodynamic polarization tests, EIS, XRD, SEM, respectively. According to the electrochemical tests, the corrosion resistance of AZ91D magnesium alloy was found to be greatly improved by means of this new environment-friendly surface treatment.

Plasma-Sprayed Hydroxylapatite-Based Coatings: Chemical, Mechanical, Microstructural, and Biomedical Properties

Science.gov (United States)

Heimann, Robert B.

2016-06-01

This contribution discusses salient properties and functions of hydroxylapatite (HA)-based plasma-sprayed coatings, including the effect on biomedical efficacy of coating thickness, phase composition and distribution, amorphicity and crystallinity, porosity and surface roughness, cohesion and adhesion, micro- and nano-structured surface morphology, and residual coating stresses. In addition, it will provide details of the thermal alteration that HA particles undergo in the extremely hot plasma jet that leads to dehydroxylated phases such as oxyhydroxylapatite (OHA) and oxyapatite (OA) as well as thermal decomposition products such as tri-(TCP) and tetracalcium phosphates (TTCP), and quenched phases such as amorphous calcium phosphate (ACP). The contribution will further explain the role of ACP during the in vitro interaction of the as-deposited coatings with simulated body fluid resembling the composition of extracellular fluid (ECF) as well as the in vivo responses of coatings to the ECF and the host tissue, respectively. Finally, it will briefly describe performance profiles required to fulfill biological functions of osteoconductive bioceramic coatings designed to improve osseointegration of hip endoprostheses and dental root implants. In large parts, the content of this contribution is a targeted review of work done by the author and his students and coworkers over the last two decades. In addition, it is considered a stepping stone toward a standard operation procedure aimed at depositing plasma-sprayed bioceramic implant coatings with optimum properties.

Tri-component phononic crystals for underwater anechoic coatings

International Nuclear Information System (INIS)

Zhao, Honggang; Liu, Yaozong; Wen, Jihong; Yu, Dianlong; Wen, Xisen

2007-01-01

Localized resonance in phononic crystal, composed of three-dimensional arrays of composite units, has been discovered recently. The composite unit is a high-density sphere coated by soft silicon rubber. In this Letter, the absorptive properties induced by the localized resonance are systemically investigated. The mode conversions during the Mie scattering of a single coated lead sphere in unbounded epoxy are analyzed by referring the elements of the scattering matrix. Then the anechoic properties of a slab containing a plane of such composite scatterers are investigated with the multiple-scattering method by accounting the effects of the multiple scattering and the viscous dissipation. The results show that the longitudinal to transverse mode conversion nearby the locally resonant region is an effective way to enhance the anechoic performance of the finite slab of phononic crystal. Then, the influences of the viscoelasticity of the silicon rubber and the coating thickness on the acoustic properties of the finite slab are investigated for anechoic optimization. Finally, we synthetically consider the destructive scattering in the finite slab of phononic crystal and the backing, and design an anechoic slab composed of bi-layer coated spheres. The results show that the most of the incident energy is absorbed at the desired frequency band

Novel coating technology for non-oriented electrical steels

Energy Technology Data Exchange (ETDEWEB)

Snell, David; Coombs, Alan

2000-06-02

An exciting combination of environmentally friendly UV curable coatings and print-on coating technology has been developed for application to semi-processed and fully processed non-oriented electrical steels. Properties exhibited by the coated steels, particularly punching, welding, insulation resistance and chemical resistance satisfy customer requirements. Coating and curing can be achieved in an energy efficient manner in a very short line space.

Suppressing Lithium Dendrite Growth with a Single-Component Coating.

Science.gov (United States)

Liu, Haodong; Zhou, Hongyao; Lee, Byoung-Sun; Xing, Xing; Gonzalez, Matthew; Liu, Ping

2017-09-13

A single-component coating was formed on lithium (Li) metal in a lithium iodide/organic carbonate [dimethyl carbonate (DMC) and ethylene carbonate (EC)] electrolyte. LiI chemically reacts with DMC to form lithium methyl carbonate (LMC), which precipitates and forms the chemically homogeneous coating layer on the Li surface. This coating layer is shown to enable dendrite-free Li cycling in a symmetric Li∥Li cell even at a current density of 3 mA cm -2 . Adding EC to DMC modulates the formation of LMC, resulting in a stable coating layer that is essential for long-term Li cycling stability. Furthermore, the coating can enable dendrite-free cycling after being transferred to common LiPF 6 /carbonate electrolytes, which are compatible with metal oxide cathodes.

Nanostructured Solar Irradiation Control Materials for Solar Energy Conversion

Science.gov (United States)

Kang, Jinho; Marshall, I. A.; Torrico, M. N.; Taylor, C. R.; Ely, Jeffry; Henderson, Angel Z.; Kim, J.-W.; Sauti, G.; Gibbons, L. J.; Park, C.;

Innovative coating of nanostructured vanadium carbide on the F/M cladding tube inner surface for mitigating the fuel cladding chemical interactions

Energy Technology Data Exchange (ETDEWEB)

Yang, Yong [Univ. of Florida, Gainesville, FL (United States); Phillpot, Simon [Univ. of Florida, Gainesville, FL (United States)

2017-11-29

Fuel cladding chemical interactions (FCCI) have been acknowledged as a critical issue in a metallic fuel/steel cladding system due to the formation of low melting intermetallic eutectic compounds between the fuel and cladding steel, resulting in reduction in cladding wall thickness as well as a formation of eutectic compounds that can initiate melting in the fuel at lower temperature. In order to mitigate FCCI, diffusion barrier coatings on the cladding inner surface have been considered. In order to generate the required coating techniques, pack cementation, electroplating, and electrophoretic deposition have been investigated. However, these methods require a high processing temperature of above 700 oC, resulting in decarburization and decomposition of the martensites in a ferritic/martensitic (F/M) cladding steel. Alternatively, organometallic chemical vapor deposition (OMCVD) can be a promising process due to its low processing temperature of below 600 oC. The aim of the project is to conduct applied and fundamental research towards the development of diffusion barrier coatings on the inner surface of F/M fuel cladding tubes. Advanced cladding steels such as T91, HT9 and NF616 have been developed and extensively studied as advanced cladding materials due to their excellent irradiation and corrosion resistance. However, the FCCI accelerated by the elevated temperature and high neutron exposure anticipated in fast reactors, can have severe detrimental effects on the cladding steels through the diffusion of Fe into fuel and lanthanides towards into the claddings. To test the functionality of developed coating layer, the diffusion couple experiments were focused on using T91 as cladding and Ce as a surrogate lanthanum fission product. By using the customized OMCVD coating equipment, thin and compact layers with a few micron between 1.5 µm and 8 µm thick and average grain size of 200 nm and 5 µm were successfully obtained at the specimen coated between 300oC and

Spectrally selective paint coatings. Preparation and characterization

Energy Technology Data Exchange (ETDEWEB)

Crnjak Orel, Z.C.; Klanjsek Gunde, M. [National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana (Slovenia)

2001-06-01

Preparation and characterization of spectrally selective paint coating for photothermal solar energy conversion are discussed. The applied methods for preparation of paints with described measurements and calculations of black-pigmented coatings were reviewed. The article represents not only possible future applications but also past and current applications of spectrally selective paint coating which are used all over the world since the 1980s. Spectrally selective paint coatings based on combinations of two types of resins, various types of pigments and three types of silica, were prepared. The influence of pigment type and pigment volume concentration (PVC) was studied by applying the Kubelka-Munk (K-M) theory. The relation between the degrees of dispersion and distribution of pigment particles across the paint layer is discussed in terms of K-M coefficients.

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.

The Influence of the Coating Deposition Process on the Interdiffusion Behavior Between Nickel-Based Superalloys and MCrAlY Bond Coats

Science.gov (United States)

Elsaß, M.; Frommherz, M.; Oechsner, M.

2018-02-01

In this work, interdiffusion between two nickel-based superalloys and two MCrAlY bond coats is investigated. The MCrAlY bond coats were applied using two different spraying processes, high velocity oxygen fuel spraying (HVOF) and low-pressure plasma spraying. Of primary interest is the evolution of Kirkendall porosity, which can form at the interface between substrate and bond coat and depends largely on the chemical compositions of the coating and substrate. Experimental evidence further suggested that the formation of Kirkendall porosity depends on the coating deposition process. Formation of porosity at the interface causes a degradation of the bonding strength between substrate and coating. After coating deposition, the samples were annealed at 1050 °C for up to 2000 h. Microstructural and compositional analyses were performed to determine and evaluate the Kirkendall porosity. The results reveal a strong influence of both the coating deposition process and the chemical compositions. The amount of Kirkendall porosity formed, as well as the location of appearance, is largely influenced by the coating deposition process. In general, samples with bond coats applied by means of HVOF show accelerated element diffusion. It is hypothesized that recrystallization of the substrate material is a main root cause for these observations.

Mechanical pretreatment for improved adhesion of diamond coatings

International Nuclear Information System (INIS)

Toenshoff, H.K.; Mohlfeld, A.; Gey, C.; Winkler, J.

1999-01-01

Diamond coatings are mainly used in cutting processes due to their tribological characteristics. They show a high hardness, low friction coefficient, high wear resistance and good chemical inertness. In relation to polycrystalline diamond (PCD)-tipped cutting inserts, especially the advantageous chemical stability of diamond coatings is superior as no binder phases between diamond grains are used. However, the deposition of adherent high-quality diamond coatings has been found difficult. Thus, substrate pretreatment is utilised to improve film adhesion. This investigation is based on water peening of the substrate material before coating. The investigation revealed best results for diamond film adhesion on pretreated substrates compared to conventional diamond coatings on cemented carbide tools applied with the CVD hot-filament process. In final cutting tests with increased film adhesion trough water peened cutting tools an improved wear behavior was detected. (orig.)

Influence of pore structure and chemical properties of supported Mo catalysts on their performance in upgrading heavy coal liquids

Energy Technology Data Exchange (ETDEWEB)

Song, C.; Hanaoka, K.; Nomura, M. (Pennsylvania State University, University Park, PA (USA). Dept. of Materials Science and Engineering)

In the hydroprocessing of solvent-refined coals, both the pore structure and the chemical properties of the catalysts affect the conversion of the heavy materials. Increasing median pore diameter (MPD) of unimodal Ni-Mo/Al[sub 2]O[sub 3] catalysts in the relatively small pore region (up to 150 [angstrom]) enhanced the conversion of both asphaltene and preasphaltene, but further increasing the MPD up to 730 [angstrom] mainly promoted preasphaltene conversion. In the runs of the isolated fractions, however, conversions increased with MPD up to 290 [angstrom] for asphaltene and up to 730 [angstrom] for preasphaltene. The degree of heteroatom removal is also influenced by MPD. There exist preferable pore size ranges for hydrodeoxygenation. Two Mo/SiO[sub 2] and several carbon-coated Ni-Mo/Al[sub 2]O[sub 3] catalysts with different MPD and a commercial Ni-Mo supported on silicated Al[sub 2]O[sub 3] were also compared. The increasing MPD of SiO[sub 2]-supported Mo catalysts increased the conversion of preasphaltene materials. Mo/SiO[sub 2] catalysts are more effective than Ni-Mo supported on Al[sub 2]O[sub 3] and silicated Al[sub 2]O[sub 3] for converting preasphaltene materials, while the latter two are more active for conversion of asphaltene into oil. Another interesting observation is that, for a given MPD range, the carbon-coated Ni-Mo/Al[sub 2]O[sub 3] catalysts gave higher preasphaltene conversions than fresh ones. These results point to the conclusion that larger pore and less acidic hydrogenation catalysts are more effective for preasphaltene conversion, but efficient conversion of asphaltene into oil is facilitated by mild hydrocracking catalysts having appropriate pore size ranges. 43 refs., 8 figs., 9 tabs.

10 CFR Appendix J to Part 110 - Illustrative List of Uranium Conversion Plant Equipment and Plutonium Conversion Plant Equipment...

Science.gov (United States)

2010-01-01

.... (2) Especially designed or prepared systems for plutonium metal production. This process usually... or UF6, conversion of UF4 to UF6, conversion of UF6 to UF4, conversion of UF4 to uranium metal, and... several segments of the chemical process industry, including furnaces, rotary kilns, fluidized bed...

SnS thin films deposited by chemical bath deposition, dip coating and SILAR techniques

Science.gov (United States)

Chaki, Sunil H.; Chaudhary, Mahesh D.; Deshpande, M. P.

2016-05-01

The SnS thin films were synthesized by chemical bath deposition (CBD), dip coating and successive ionic layer adsorption and reaction (SILAR) techniques. In them, the CBD thin films were deposited at two temperatures: ambient and 70 °C. The energy dispersive analysis of X-rays (EDAX), X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM) and optical spectroscopy techniques were used to characterize the thin films. The electrical transport properties studies on the as-deposited thin films were done by measuring the I-V characteristics, DC electrical resistivity variation with temperature and the room temperature Hall effect. The obtained results are deliberated in this paper.

Enzyme-driven Bacillus spore coat degradation leading to spore killing.

Science.gov (United States)

Mundra, Ruchir V; Mehta, Krunal K; Wu, Xia; Paskaleva, Elena E; Kane, Ravi S; Dordick, Jonathan S

2014-04-01

The bacillus spore coat confers chemical and biological resistance, thereby protecting the core from harsh environments. The primarily protein-based coat consists of recalcitrant protein crosslinks that endow the coat with such functional protection. Proteases are present in the spore coat, which play a putative role in coat degradation in the environment. However these enzymes are poorly characterized. Nonetheless given the potential for proteases to catalyze coat degradation, we screened 10 commercially available proteases for their ability to degrade the spore coats of B. cereus and B. anthracis. Proteinase K and subtilisin Carlsberg, for B. cereus and B. anthracis spore coats, respectively, led to a morphological change in the otherwise impregnable coat structure, increasing coat permeability towards cortex lytic enzymes such as lysozyme and SleB, thereby initiating germination. Specifically in the presence of lysozyme, proteinase K resulted in 14-fold faster enzyme induced germination and exhibited significantly shorter lag times, than spores without protease pretreatment. Furthermore, the germinated spores were shown to be vulnerable to a lytic enzyme (PlyPH) resulting in effective spore killing. The spore surface in response to proteolytic degradation was probed using scanning electron microscopy (SEM), which provided key insights regarding coat degradation. The extent of coat degradation and spore killing using this enzyme-based pretreatment approach is similar to traditional, yet far harsher, chemical decoating methods that employ detergents and strong denaturants. Thus the enzymatic route reduces the environmental burden of chemically mediated spore killing, and demonstrates that a mild and environmentally benign biocatalytic spore killing is achievable. © 2013 Wiley Periodicals, Inc.

Radiation curable coating compositions

International Nuclear Information System (INIS)

Jenkinson, R.D.; Carder, C.H.

1979-01-01

The present invention provides a low-toxicity diluent component for radiation curable coating compositions that contain an acrylyl or methacryly oligomer or resin component such as an acrylyl urethane oligomer. The low-toxicity diluent component of this invention is chosen from the group consisting of tetraethlorthosilicate and tetraethoxyethylorthosilicate. When the diluent component is used as described, benefits in addition to viscosity reduction, may be realized. Application characteristics of the uncured coatings composition, such as flowability, leveling, and smoothness are notably improved. Upon curing by exposure to actinic radiation, the coating composition forms a solid, non-tacky surface free of pits, fissures or other irregularities. While there is no readily apparent reactive mechanism by which the orthosilicate becomes chemically bonded to the cured coating, the presence of silicon in the cured coating has been confirmed by scanning electron microscopy. 12 drawing

Aging study on carboxymethyl cellulose-coated zero-valent iron nanoparticles in water: Chemical transformation and structural evolution

Energy Technology Data Exchange (ETDEWEB)

Dong, Haoran, E-mail: dongh@hnu.edu.cn [College of Environmental Science and Engineering, Hunan University, Changsha, Hunan 410082 (China); Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, Hunan 410082 (China); Zhao, Feng; Zeng, Guangming; Tang, Lin; Fan, Changzheng; Zhang, Lihua; Zeng, Yalan; He, Qi; Xie, Yankai; Wu, Yanan [College of Environmental Science and Engineering, Hunan University, Changsha, Hunan 410082 (China); Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, Hunan 410082 (China)

2016-07-15

Highlights: • The chemical transformation and structural evolution of CMC-nZVI were investigated. • CMC could slow down the aging rate of nZVI and alter the species transformation. • Fe{sub 3}O{sub 4} and/or γ-Fe{sub 2}O{sub 3} are the dominant corrosion products of bare nZVI after aging. • γ-FeOOH is the primary corrosion product of CMC-nZVI after aging. - Abstract: To assess the long-term fate and the associated risks of nanoscale zero-valent iron (nZVI) used in the water remediation, it is essential to understand the chemical transformations during aging of nZVI in water. This study investigated the compositional and structural evolution of bare nZVI and carboxymethyl cellulose (CMC) coated nZVI in static water over a period of 90 days. Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), X-ray diffraction (XRD) and Raman spectroscopy were used to characterize the corrosion products of nZVI and CMC-nZVI. Results show that both the structures and the compositions of the corrosion products change with the process of aging, but the coating of CMC could slow down the aging rate of nZVI (as indicated by the slower drop in Fe{sup 0} intensity in XRD pattern). For the bare nZVI, magnetite (Fe{sub 3}O{sub 4}) and/or maghemite (γ-Fe{sub 2}O{sub 3}) are the dominant corrosion products after 90 days of aging. However, for the CMC-nZVI, the core-shell spheres collapses to acicular-shaped structures after aging with crystalline lepidocrocite (γ-FeOOH) as the primary end product. Moreover, more lepidocrocite present in the corrosion products of CMC-nZVI with higher loading of CMC, which reveals that the CMC coating could influence the transformation of iron oxides.

Aging study on carboxymethyl cellulose-coated zero-valent iron nanoparticles in water: Chemical transformation and structural evolution

International Nuclear Information System (INIS)

Dong, Haoran; Zhao, Feng; Zeng, Guangming; Tang, Lin; Fan, Changzheng; Zhang, Lihua; Zeng, Yalan; He, Qi; Xie, Yankai; Wu, Yanan

2016-01-01

Highlights: • The chemical transformation and structural evolution of CMC-nZVI were investigated. • CMC could slow down the aging rate of nZVI and alter the species transformation. • Fe_3O_4 and/or γ-Fe_2O_3 are the dominant corrosion products of bare nZVI after aging. • γ-FeOOH is the primary corrosion product of CMC-nZVI after aging. - Abstract: To assess the long-term fate and the associated risks of nanoscale zero-valent iron (nZVI) used in the water remediation, it is essential to understand the chemical transformations during aging of nZVI in water. This study investigated the compositional and structural evolution of bare nZVI and carboxymethyl cellulose (CMC) coated nZVI in static water over a period of 90 days. Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), X-ray diffraction (XRD) and Raman spectroscopy were used to characterize the corrosion products of nZVI and CMC-nZVI. Results show that both the structures and the compositions of the corrosion products change with the process of aging, but the coating of CMC could slow down the aging rate of nZVI (as indicated by the slower drop in Fe"0 intensity in XRD pattern). For the bare nZVI, magnetite (Fe_3O_4) and/or maghemite (γ-Fe_2O_3) are the dominant corrosion products after 90 days of aging. However, for the CMC-nZVI, the core-shell spheres collapses to acicular-shaped structures after aging with crystalline lepidocrocite (γ-FeOOH) as the primary end product. Moreover, more lepidocrocite present in the corrosion products of CMC-nZVI with higher loading of CMC, which reveals that the CMC coating could influence the transformation of iron oxides.

Nanocarbon-Coated Porous Anodic Alumina for Bionic Devices

Directory of Open Access Journals (Sweden)

Morteza Aramesh

2015-08-01

Full Text Available A highly-stable and biocompatible nanoporous electrode is demonstrated herein. The electrode is based on a porous anodic alumina which is conformally coated with an ultra-thin layer of diamond-like carbon. The nanocarbon coating plays an essential role for the chemical stability and biocompatibility of the electrodes; thus, the coated electrodes are ideally suited for biomedical applications. The corrosion resistance of the proposed electrodes was tested under extreme chemical conditions, such as in boiling acidic/alkali environments. The nanostructured morphology and the surface chemistry of the electrodes were maintained after wet/dry chemical corrosion tests. The non-cytotoxicity of the electrodes was tested by standard toxicity tests using mouse fibroblasts and cortical neurons. Furthermore, the cell–electrode interaction of cortical neurons with nanocarbon coated nanoporous anodic alumina was studied in vitro. Cortical neurons were found to attach and spread to the nanocarbon coated electrodes without using additional biomolecules, whilst no cell attachment was observed on the surface of the bare anodic alumina. Neurite growth appeared to be sensitive to nanotopographical features of the electrodes. The proposed electrodes show a great promise for practical applications such as retinal prostheses and bionic implants in general.

Development of Zn-Al-Cu coatings by hot dip coated technology: preparation and characterization

International Nuclear Information System (INIS)

Cervantes, J.; Barba, A.; Hernandez, M. A.; Salas, J.; Espinoza, J. L.; Denova, C.; Torres-Villasenor, G.; Conde, A.; Covelo, A.; Valdez, R.

2013-01-01

In the present study, research concerning Zn-Al-Cu coatings on low carbon steels has been conducted in order to characterize different properties obtained by a hot-dip coated process. The results include preparation procedure as well as the processing parameters of the coatings. The obtained coatings were subjected to a cold rolling process followed by an anneal heat treatment at different temperatures and under different time conditions. The structural characteristics of coatings have been investigated by optical and electron microscopy. The mechanical properties were obtained by using micro-hardness testing, deep drawing and wear tests whereas chemical analyses were carried out using the SEM/EDAX microprobe. The corrosion properties were achieved by using a salt spray fog chamber and potentiodynamic tests in a saline solution. The coatings are resistant to corrosion and wear in the presence of sodium chloride, therefore, the coatings could be an attractive alternative for application in coastal areas, and adequate wear adhesive resistance. (Author)

Chemical conversion of natural gas. Final report; Kjemisk konvertering av naturgass. Sluttrapport

Energy Technology Data Exchange (ETDEWEB)

Simonsen, Haavard

2000-07-01

This report presents examples of gas research of a high international class. This research has strengthened the technological position of Norwegian industry in the field of gas utilization, which will be of great importance for Norwegian industry, nationally and internationally. The competence of the research and development institutions has been further developed within the subjects of catalysis, reactor technology and chemical engineering. These subjects are of central importance irrespective of whether or not the gas is to be utilized with or without CO{sub 2} deposition, for synthetic diesel, for methanol, for olefins, for proteins, for hydrogen or other purposes. The main purpose of the programme discussed was to educate PhDs and to develop skill of strategic importance for Norwegian industry. There are sections on synthesis gas, direct conversion, methanol to olefins, fluidized bed reactors and system technology.

Fabrication of Up-Conversion Phosphor Films on Flexible Substrates Using a Nanostructured Organo-Silicon.

Science.gov (United States)

Jeon, Young-Sun; Kim, Tae-Un; Kim, Seon-Hoon; Lee, Young-Hwan; Choi, Pil-Son; Hwang, Kyu-Seog

2018-03-01

Up-conversion phosphors have attracted considerable attention because of their applications in solid-state lasers, optical communications, flat-panel displays, photovoltaic cells, and biological labels. Among them, NaYF4 is reported as one of the most efficient hosts for infrared to visible photon up-conversion of Yb3+ and Er3+ ions. However, a low-temperature method is required for industrial scale fabrication of photonic and optoelectronic devices on flexible organic substrates. In this study, hexagonal β-NaYF4: 3 mol% Yb3+, 3 mol% Er3+ up-conversion phosphor using Ca2+ was prepared by chemical solution method. Then, we synthesized a nanostructured organo-silicon compound from methyl tri-methoxysilane and 3-glycidoxy-propyl-trimethoxy-silane. The transmittance of the organo-silicon compound was found to be over 90% in the wavelength range of 400~1500 nm. Then we prepared a fluoride-based phosphor paste by mixing the organo-silicon compound with Na(Ca)YF4:Yb3+, Er3+. Subsequently, this paste was coated on polyethylene terephthalate, followed by heat-treatment at 120 °C. The visible emission of the infrared detection card was found to be at 655 nm and 661 nm an excitation wavelength of 980 nm.

Waterborne UV coating for industrial applications

International Nuclear Information System (INIS)

Bhattacharya, I.N.

2007-01-01

(Full Text): Solvent borne industrial coatings are being replaced by environment friendly coatings like Ultra Violet (UV) or Electron Beam (Eb) cured coatings, Powder coatings and Waterborne coatings. Waterborne systems enjoy the biggest share from this shift. UV and EB coatings provide the advantages of instant cure at room temperature, high scratch and abrasion resistance combined with excellent chemical resistance. Polyurethane (PU) chemistry is the dominant chemistry in Industrial coatings as they provide a very high level of performance. Most PU coatings are solvent based 2-component systems comprising of a resin and a cross linker. Polyurethane dispersions (PUD) in water in single pack are available but mainly addresses the Do It Yourself (DIY) market because of their slow drying speeds. Performance of PUD in most cases is inferior to solvent borne 2-component PU systems.Therefore the combination of PU dispersion and UV/EB curable technology has led to new innovative waterborne polymers called UV curable polyurethane dispersions (UVPUD). UVPUD are zero VOC systems as they are coalescent free. They are higher in molecular weight than standard UV curable products resulting in lower shrinkage coatings and provide good adhesion to substrates. Their low-viscosity makes them suitable for application by spray, curtain coater and even roller coater, without having to use monomers. UVPUD display superior chemical and mechanical properties necessary to protect high quality surface from the challenging usage conditions. UVPUD resins are therefore tailor-made to address performance needs like excellence in outdoor durability, scratch resistance, stain resistance, adhesion etc. UVPUD technology is now growing rapidly in industrial coatings for applications such as resilient flooring, wooden parquet flooring, automotive interior plastics, mobile phones etc. (Author)

The formation of FHA coating on biodegradable Mg-Zn-Zr alloy using a two-step chemical treatment method