Post treatment of thermal spraying coating

       Sometimes the coating obtained by spraying cannot be used directly, and a series of post-treatments are necessary. Coating for anti-corrosion In order to prevent corrosive medium from reaching the substrate through the pores of the coating and causing corrosion of the substrate, the coating must be sealed. There are many materials used as sealing agent, but it should be considered according to various factors such as the working medium, environment, temperature and cost of the workpiece.

For workpieces subjected to high stress load or impact wear, in order to improve the bonding strength of the coating, the sprayed layer must be remelted (such as flame remelting, induction remelting, laser remelting, hot isostatic pressing, etc.) to make it porous The coating that is only mechanically bonded to the substrate becomes a dense coating that is metallurgically bonded to the substrate. If the dimensional accuracy is required, the coating must be mechanically processed.

Because the spray coating has different characteristics from ordinary metal and ceramic materials, such as the coating has micropores, which is not conducive to heat dissipation; the strength of the coating itself is low and cannot withstand large cutting forces; there are many hard coatings in the coating. Particles, wear quickly on the tool, etc., thus forming the characteristics of spray coating that is difficult to process, which is different from ordinary materials. Therefore, reasonable processing methods and corresponding process parameters must be selected to ensure the smooth progress of the spray coating mechanical processing and to ensure the required dimensional accuracy.