Aluminum Water System Metal Powder Coating Process Research

With the development of modern science and technology, there are higher requirements for the decorative and surficial performance of materials, and many methods of surface treatment come forth. Due to the pollution produced during the process, however, conventional methods of surface treatment, such as hot dip coating and electroplating, is restricted from further development in many countries and areas. With perfect corrosion resistance and free of pollution, Dacromet, a typical representative of metallic micro-powder coating, get more eyes.According to the definition of metallic micro-powder coating, this thesis summarized the characteristics of prevailing technology of metallic micro-powder coatings. And the conception of aluminum based water-soluble metallic micro-powder coating was brought forward. Using aluminum powder as substrate and innoxious inorganic water-soluble salts as adhesives, the process of aluminum based water-soluble metallic micro-powder coating was developed. It's capability was compared with that of Dacromet.Starting with the preparation of micro-powder used in aluminum based water-soluble metallic micro-powder coating, and in reference to basic theories of physics, chemistry, metallurgy, process of mineral whetting, mill running and physical chemistry about mechanical alloying, this thesis designed the equipment for micro-powder preparation, and the relevant parameters of the equipment were confirmed. Using this experimental equipment, metallic micro-powder for coating was produced. The shape and granularity of original powder and micro-powder were observed and studied through microscope and SEM, and the different moist capability of those metallic powders was compared through experiment as well.After many times of test, the formula of aluminum based water-soluble metallic micro-powder coating was found. Those formulas were optimized through the quadrature experiment. The best sinterprocess was stipulated and coatings with good corrosion resistance were then obtained. The effects of different ingredients and methods of operation on the performance of coating were also discussed.In this thesis, the corrosion resistance, heat resistance, bonding strength and porosity of the coating were studied and comparisons of these properties with other coatings were also included.The appearance of coating was observed and studied through microscope, SEM, and EDS. The chemical compositions of substrate, the internal, middle, and external layer of coating were statistically analyzed. At the same time, the primary model of coating structure was built up in this thesis.Because the conception of aluminum based water-soluble metallic micro-powder coating was brought forward for the very first time in this thesis, and the process of micro-powder preparation, formula research and property analysis of the coating were also included, the contents of this thesis were so complex. Jn order to put this process into industrial use, there are still many problems waiting for further research and amelioration.