Waterborne Chromium Zinc-aluminum Coating Preparation And Properties

Anti-corrosion coating of metal produce is effective means for corrosion. The anti-corrosion coating relied on constructing simply the low-cost, well anti-corrosion and so on, has attracted widely attention. With the development of technology, industry metallic anti-corrosion is confronted with the pressure from both environment protection and energy-conservation. Dacromet coating will be forbidden in further, so, it is necessary to find a substitute for chromate.Firstly, the basic components have been selected, after lots of experiment. We get the watering bonding. The selection of substitute for chromate was the key and the most difficult work in the experiment. Impact of reaction temperature, type of agitation, speed of adding solution and so on has been studied. Results show that reaction temperature around 50℃, produced with magnetic agitation, control the adding speed is proper to prepare the products of the stability and transparence.Secondly, the silica encapsulation of aluminum flakes provided aluminum pigments used in the water-based coating by thesis. The effect of the relate factors of the process is studied, the reaction temperature is 45℃, the reaction time is 9 hours. Encapsulated aluminum flakes were characterized by scanning electron microscopy (SEM), energy spectrum instrument (EDS), laser particle size and XRD measurer.The results showed that aluminum flakes turned to being water-inert and hydrophilic after being coated by layer of silica.Finally, the processing parameters of preparation for non-chrome coating have been studied. We used SEM EDS and XRD to observe and analyze the element of the coating. Produced the water-based coating with different proportion of zinc and aluminum powder, then, researched by contrasting the performance of these coatings. After the researched on the components and preparation process, the non-chrome zinc-aluminum coating with the best performances was prepared. The proportion of zinc and aluminum powder is 3:1, and the binder is 20%. The anti-corrosion performance cohesion as well as appearance were tested.Watering non-chrome Zinc-Aluminum coating, as a new type of environmental-friendly protection coating must have broad market prospects. But there are many things to be done before putting this process into industrial use, because the experiment needs much further research and amelioration.