Effect of substrate temperature on the adhesion properties of magnetron sputtered nano-composite Si-C-N hard thin films

The adhesion and film failure studies on nano-composite SiCN thin films on silicon, glass and steel have been carried out. It was observed that both coating as well as the substrate has an influence on the adhesion of film. The films on hard substrate Si failed adhesively whereas on softer substrate, steel, cohesive failure was observed. The measured critical load was around 18 N and 24 N for SiCN film on silicon and steel substrate respectively. A decrease in critical load and interface toughness with the increase of substrate temperature during deposition for glass and steel substrate was observed.     

水性三聚氰胺树脂抗静电涂层的制备

在三聚氰胺甲醛树脂中掺杂结晶SnCl4·5H2O，增加树脂的抗静电性。制备出水性抗静电涂层，测定表面电阻，并通过红外光谱和热重差热对涂层进行表征。结果表明，三聚氰胺甲醛树脂本身不具备导电性，结晶SnCl4·5H2O的添加使三聚氰胺甲醛树脂导电性大大增加，水分的吸收有利于导电性的提高。20g40％的三聚氰胺甲醛树脂溶液中添加17．8gSnCl4·5H2O形成树脂溶液制备的涂层，在温度60℃，湿度为40％环境中干燥处理4h，涂层表面电阻率可低至1．39×10^7Ω·cm，在室温空气环境中电阻率可降低至8．80×10^6Ω·cm。     

金属构件的防腐问题

介绍了金属腐蚀造成的危害及其防腐措施。     

Phase formation in a Ni-50Cr HVOF coating

A complex, fine scale microstructure of non-equilibrium phases is obtained by HVOF deposition of Ni-50Cr alloy due to the rapid cooling experienced by the splats which make up the as-deposited coatings. XRD analyses indicated that the as-deposited coatings consisted predominantly of a single fcc γ-Ni phase. Two small peaks suggested the presence of NiO and/or NiCr₂O₄ at the limit of detection (∼ 5%). Shoulders on the main γ-Ni peaks were interpreted as evidence of a second, lower Cr content γ-Ni phase. Characterization of the oxide content of the as-deposited coatings by X-ray diffraction, image analysis of backscattered electron images, and electron probe microanalysis yielded conflicting results due to the size of the microstructural features present relative to the spatial resolution of these techniques. Due to the nature and feature size of the non-equilibrium oxide phase(s), direct measurement of the oxygen content by EPMA was found to be the most accurate technique. Heat treatment of an as-deposited coating at 650 °C in vacuum resulted in coarsening of the microstructural features, and an approach towards a mixture of equilibrium phases consisting of γ-Ni, α-Cr, and Cr₂O₃. Evidence was also seen in the XRD pattern of an intermetallic σ phase that has previously only been reported in thin films of Ni-Cr alloys.     

Glass and glass-ceramic coatings, versatile materials for industrial and engineering applications

Among various coating systems for industrial and engineering applications, glass and glass-ceramic coatings have advantages of chemical inertness, high temperature stability and superior mechanical properties such as abrasion, impact etc as compared to other coating materials applied by thermal spraying in its different forms viz. PVD, CVD, plasma, etc. Besides imparting required functional properties such as heat, abrasion and corrosion resistance to suit particular end use requirements, the glass and glass-ceramic coatings in general also provide good adherence, defect free surface and refractoriness. Systematic studies covering the basic science of glass and glass-ceramic coatings, the functional properties required for a particular end-use along with the various fields of application have been reviewed in this paper.     

二极管泵浦Nd∶YVO_4倍频激光器使用的光学薄膜

讨论了二极管泵浦 Nd∶ YVO4 激光器中使用的一系列光学薄膜 ,膜系类型涉及截止滤光片、增透膜等。根据设计对称匹配膜层的分析 ,利用计算机膜系设计优化软件对膜系进行优化 ,得到损耗小、利于制备、重复性好的膜系设计。用于实际制备 ,取得较好的效果     

Cathodic disbonding of a thick polyurethane coating from steel in sodium chloride solution

The cathodic disbonding of a thick, pigmented polyurethane coating from steel in 3.5 wt.% NaCl solution was studied by using an electrochemical AC impedance technique. Double-cylinder electrolyte cells were designed to separate the measurements of cathodic disbonding process from the influence of the impedance of an artificial defect. It was found that for a thick, pigmented polyurethane coating, the more important transport pathway of the reactive species is along the coating/steel interface rather than through the coating. There existed a delay time for the cathodic disbonding process, and cathodic polarization was not a predominant factor in determining the cathodic disbonding behavior in the early stages. The thick polyurethane coating, which was applied on a well sand-blasted steel surface, had excellent resistance to cathodic disbonding.     

Impacts of impregnation with Timbercare Aqua on the red and yellow color tone of some woods and varnishes

This study has been performed for determining the effects of impregnation with Timbercare Aqua (Tc) on the red and yellow color tone of some woods and varnishes. For this purpose, the test samples prepared from Oriental beech, European oak, Scotch pine, Oriental spruce, and Uludag fir woods, which met the requirements of ASTM D 358, was impregnated with Tc according to ASTM D 1413 and producer's definition. After impregnation, wood surfaces have been coated by Sayerlack parquet varnish (Sp), Sayerlack interior varnish (Si), and Sayerlack exterior varnish (Se) varnishes in accordance with the ASTM D 3023 standards. According to ASTM D 2244, the red and yellow color tone of samples after varnishing process was determined. As a result, the value of red color tone was the highest in Oriental beech (15.21) and the lowest in Uludag fir (5.38). For the wood material, impregnation material, and varnish interaction, the red color tone value was the highest in Oriental beech + Tc + Sp (18.43) and the lowest in Uludag fir + Tc + Si (3.92). The value of the yellow color tone was the highest in pine (34.45) and the lowest in Oriental beech (26.50). For the wood material, impregnation material, and varnish interaction, the yellow color tone value was the highest in Oriental spruce + Tc + Sp (42.12) and the lowest in Oriental beech + Tc + Si (21.47). This effect may be due to the impacts of impregnation chemical on wood extractives and color pigments in varnish. Accordingly, it should be taken into care for applications where the red and yellow color tone value is important. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

New procedure to calculate the Hansen solubility parameters of polymers

The simplest experimental method to determine the Hansen solubility parameters (HSPs) for a polymer is to evaluate whether or not it dissolves in selected solvents. Those solvents dissolving the polymer will have HSPs closer to those of the polymer than those that do not. A computer program or graphical method can then be used to find the HSP for the polymer. In this work, an improved method for calculating the HSP of polymers, based on the Nelder–Mead optimization algorithm, is presented. The results of this program fit the data very well. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 31–36, 2007     

Acrylic‐based nanocomposite resins for coating applications

Acrylic‐based nanocomposite resins have been investigated in view of future application in water borne automotive coatings by the aid of postemulsification processes. Mechanical, flow and leveling properties of the nanocomposite resins, containing various concentrations of silicate, have been investigated. The results are related to morphological information obtained from TEM and WAXS measurements in the liquid suspension as well as from the cured film. At low silicate loadings, when flow properties are still acceptable for typical emulsification processing, a strong increase in modulus of the cured coating films is observed because of the mainly exfoliated silicate platelets. The rate of increase in modulus of the cured films decreases at higher silicate loadings. Analyzing the mechanical data, using Halpin–Tsai theory indicates that this is due to less perfect exfoliation at higher silicate loading, which is confirmed by TEM analysis. In addition at higher silicate loading, the flow properties of the resin as analyzed by DMA show solid‐like behavior. This can lead to poor film formation in future application. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2146–2156, 2007