ATO半导体颜料在伪装涂料中的应用研究

以SnCl4、SbC13、NaOH等为原料,采用共沉淀法制备ATO半导体颜料,采用XRD、SEM、EDS对颜料结构、成分、形貌进行表征,比较了ATO半导体颜料与常见的单组分颜料涂层红外发射率大小。通过颜色混合规律将ATO半导体颜料与着色颜料混合制备了绿色伪装涂料,制备的涂层具有较低的红外发射率,并且其光谱反射曲线满足美军标的光谱通道要求,具有较好的应用前景。     

Cathodic delamination: Quantification of ionic transport rates along coating–steel interfaces

So-called cathodic delamination is one of the major modes of failure for organic coatings immersed in electrolyte solutions (e.g. seawater). Cathodic delamination occurs as a result of the electrochemical reactions, which takes place on a corroding steel surface. This means that reactants must continuously be transported from the bulk solution to the cathodic areas. The transport of sodium ions from a defect in the coating to the cathodic areas is generally considered the rate-determining step for cathodic delamination because the transport of oxygen and water through the coating is sufficient for the corrosion processes. In this work, a novel practical method, which allows direct estimation of the apparent diffusion coefficient of sodium ions in the ultrathin aqueous layer at the coating–steel interface, is described. The apparent diffusion coefficients estimated are of similar magnitude as previously reported values and show an acceptable repeatability. The method was used to obtain the apparent diffusion coefficients of sodium ions in the coating–steel interface for three commercial inert-pigmented epoxy coatings. The delamination rates predicted using the apparent interfacial diffusion coefficients and Fick's second law, under the assumption of a transport controlled mechanism, show qualitative agreement with the observed delamination rates in 0.5 M sodium chloride. This confirms that the rate-determining step of cathodic delamination is the transport of sodium ions along the coating–steel interface.     

The influence of aluminium surface pretreatment on the corrosion stability and adhesion of powder polyester coating

One of the most important factors in corrosion prevention by protective coatings is the coating adhesion loss under environmental influence. Thus, adhesion strength is often used when characterizing protective properties of organic coatings on a metal substrate. In order to improve the adhesion of organic coating the metal substrate is often pretreated in some way. In this work, the adhesion of polyester coatings on differently pretreated aluminium surface (by anodizing, with and without sealing, by phosphating and by silane film deposition) was examined. The dry and wet adhesion of polyester coatings were measured by a direct pull-off standardized procedure, as well as indirectly by NMP test. It was shown that under dry test conditions all polyester coatings showed very good adhesion, but that aluminium surface pretreated by silane film showed superior adhesion. The overall increase of wet adhesion for polyester coating on aluminium pretreated by silane film was maintained throughout the whole investigated time period. The different trends in the change of adhesion of polyester coatings were observed for different aluminium pretreatments during exposure to the corrosive agent (3% NaCl solution). The highest adhesion reduction was obtained for polyester coating on aluminium pretreated with phosphate coating. The corrosion stability of polyester coated aluminium was investigated by electrochemical impedance spectroscopy in 3% NaCl solution. The results confirmed good protective properties of polyester coating on aluminium pretreated with silane film, i.e. greater values of pore resistance and smaller values of coating capacitance were obtained in respect to other protective systems, whereas charge-transfer resistance and double-layer capacitance were not measurable during 2 months of exposure to a corrosive agent.     

Cathodic delamination of seawater-immersed anticorrosive coatings: Mapping of parameters affecting the rate

Cathodic delamination is one of the major modes of failure for organic coatings immersed in seawater and refers to the weakening or loss of adhesion between the coating and the substrate. The diminished adhesion is the result of electrochemical reactions occurring at the coating–steel interface, where solid iron is oxidized to ferrous ions and oxygen is reduced to hydroxyl ions. In this work, the effects of various parameters on cathodic delamination have been investigated. The parameters are: permeability of the coating, concentration of dissolved oxygen and cations, polarization potential, type of binder, degree of curing, and pigment loading, shape and type. The results show that cathodic delamination increases with increasing concentration of cations up to the point where the concentration of dissolved oxygen becomes insufficient to maintain the corrosion rate. The rate of cathodic delamination is inversely proportional to the magnitude of polarization potential when ions can penetrate the coating, while cathodic polarization does not affect cathodic delamination when the ionic transport is restricted to the coating–steel interface. Increasing the pigment loading or partial replacement of spherical pigments with flake-shaped micaceous iron oxide or aluminium pigments reduces the rate of cathodic delamination. Finally, binders with an increasing amount of secondary hydroxyl groups in the polymer backbone reduce the rate of cathodic delamination while increasing the initial molar ratio of amide to epoxide increases cathodic delamination.     

Preparation and characterization of flame retardant solvent base and emulsion paints

In this research solvent base alkyd and emulsion paint formula were made flame retardant (FR) by incorporation of hexachlorodiphosh (V) azane of types (I–III). Elemental analysis was used to characterize the structure of these compounds. These additives are physically incorporated into the paint formula through grinding in a pebble mill until all particulates have a size below 38 μm. Experimental coatings were manufactured on a laboratory scale, applied by brush on wood and steel panels. Results of an oxygen index value indicated that coating with these compounds containing chlorine, nitrogen and phosphorus exhibit very good flame retardant effect when mixed with solvent base alkyd and emulsion paint. The physical, mechanical and corrosion resistance were studied to evaluate the additives drawbacks. The additives did not affect the flexibility and pinholes of paint formula. The gloss and the impact strength were decreased by the additives, the hardness and adhesion resistance increased by the additives. However, corrosion resistance was not significantly changed by these additives.     

自润滑复合镀层的摩擦学性能及其强化机理分析

探讨自润滑复合镀层的摩擦学性能及其增强相的摩擦磨损强化机理;分析经具有自润滑性能的石墨、二硫化钼、聚四氟乙烯及碳纳米管等改性的复合镀层的摩擦学行为;并探讨该类复合镀层的摩擦磨损强化机制。     

影响PU哑光白面漆耐黄性能的因素探讨

文章简单介绍了PU漆黄变的机理,并通过人工老化实验,对比分析不同因素对PU白面漆耐黄性能的影响。     

一种重防腐涂料用复合流变剂的制备及性能研究

文章介绍了一种新型胶体复合流变剂的制备以及在重防腐涂料等高固含涂料体系中的应用。结果表明,该防沉剂能够有效的提高重防腐涂料的储存稳定性,提高防沉抗流挂效果,与普通膨润土流变剂相比,该防沉剂能够降低对涂料光泽度的影响。     

舰船防火涂料的应用及发展趋势

防火涂料以其涂层薄、涂装方便、防火效力强等特点在舰船防火中具有很大的优势,英国、美国、澳大利亚等海军都研制出能够提供1~2 h防火保护的舰艇用防火涂料。涂装部位主要为人工操作间、生活舱、弹药舱、机舱、辅助锅炉舱、发射舱、泵舱的舱壁和舱顶及通风管道等。我国在舰船舱室的防火保护上,与国外舰艇还存在一定差距。     

几种典型舰船涂料太阳反射率测试对比分析

介绍了舰船涂料太阳反射率测试仪器及方法,测试了几种典型舰船涂料的太阳热反射率,并对测试结果进行了对比分析。