1. thermal spraying
Thermal spraying is the use of some heat source to heat the coating material to molten or semi-molten state, and with the help of flame flow and high-speed gas atomization, and promote these atomized particles spray to the surface of the matrix, deposition into a coating with a certain function. Thermal spraying can provide wear resistance, corrosion resistance, high temperature resistant coating on the workpiece surface. There are usually three bonding modes between coating materials and substrate: mechanical bonding, physical bonding and metallurgical bonding. With the emergence of low-pressure plasma spraying, high-energy, high-speed plasma spraying and high-speed flame spraying, the performance of the coating has been further improved: the porosity can be reduced to 015% ~ 1%; The bonding strength between the coating and the substrate can reach 70 ~ 140MPa.
Studies have shown that Using supersonic flame spraying (HVOF) technology and plasma spraying (ASP) technology, respectively in 0 cr13ni5mo iron-based amorphous alloy was prepared on stainless steel substrates and iron-based amorphous nanocrystalline coating, coating is studied two kinds of coating on the friction and wear properties at room temperature, the results show that both kinds of preparation of iron base coating spraying process, has higher microhardness and more Small porosity, dense structure, typical layered structure, improve the wear resistance of the coating.
In order to make up for the weakness of stainless steel soft non-wear resistance, friction coefficient is large, commonly used electroplating method to improve the surface hardness and self-lubrication performance of stainless steel transmission shaft and other parts. Stainless steel is a kind of surface easy passivation metal, must remove the surface passivation film before electroplating, stainless steel after deoiling, impregnation, activation, pre-nickel plating and electroplating and other processes, chromium, zinc, copper, tin, precious metal coating.
The results show that the thickness of the coating is about 013mm, and the coating is composed of the metal base phase and the second phase of rare earth salt particles. The hardness of the coating can reach 900 ~ 1000Hv. The corrosion resistance of the coating is 25 ~ 28 times that of the base metal, and the product life is 2 ~ 6 times higher than that of the original stainless steel