The metal coating process is mainly to make the raw materials into water-soluble coating solution, and then directly coated on the surface of the activated workpiece, after drying, sintering to form a layer of non-polar film, metal coating in the process of using common problems How much do you know?
1, the instability of the coating solution: Due to the greater density of zinc powder, the configuration of the paint is relatively easy to sediment, the coating solution stratification, for which the choice must be efficient thickener. The use of sodium polyacrylate coating thickening, when added in excess, the coating is very easy to gel, thereby shortening the service life. From the coating liquid life and productivity are not suitable;
2, coating the surface color: coated with advanced raw materials after the workpiece, the treated surface color is silver white. Found in the production process, the ratio of zinc powder and aluminum have a greater impact on the color, increase the amount of aluminum powder can increase the silver-white parts. After the amount of aluminum powder increases, the corrosion resistance of the workpiece has a certain impact;
3, chromic acid pH effect: coating solution, there is a component that must be considered, namely, chromic acid solution. In the actual preparation process, if the chromic acid has a high pH value, the chromic acid reacts with the slurry very violently, releasing a large amount of heat and then caking the entire solution system. If diluted with water after coating, the workpiece surface adhesion decreased, easy peeling;
4, mixing time on the quality of zinc-chromium coating layer: After the coating ingredients must be stirred to make the slurry mixed with chromic acid and other components and the reaction curing. With a good coating fluid has a useful life, stored in a closed container, and kept stirring, can be used for 3 days;
5, the impact of wetting agent: The workpiece is coated steel parts, wetting the coating surface in the workpiece, spreading good or bad, directly affect the quality of the layer. If the wetting and spreading is not good, the surface of the workpiece will be missed and need to be coated several times to cover the surface of the workpiece. As a result, the coating is uneven and the corrosion resistance of the coating is reduced.
The above is the common problem of metal coating in use, would like to know more details, please call for details.
