Method for spraying composite coating onto emulsification pump plunger and plunger including composite coating

Abstract

The invention discloses a method for spraying a composite coating onto an emulsification pump plunger. The method comprises the following steps that (1) a metal plunger matrix is subjected to oil removal treatment, and sand blasting is carried out after drying; (2) a metal plunger obtained after sand blasting is preheated, and a NiCrAl and Al2O3 containing composite transition layer is sprayed onto the metal plunger through supersonic plasma; (3) after the composite transition layer is sprayed, a Al2O3 and TiO2 composite ceramic face layer is sprayed onto the surface of the composite metal transition layer through supersonic plasma; and (4) the metal plunger with the ceramic face layer sprayed is subjected to rough grinding, accurate grinding and polishing treatment, and the composite coating is obtained. Through the adoption of the method, a supersonic plasma method is utilized, the contents of Al2O3 and TiO2 in the composite coating are controlled, and the obtained coating is high inbonding strength, even in coating surface and high in density and hardness; and compared with a full ceramic plunger, the plunger is not prone to being damaged, the binding force of the coating and the matrix is high, the plunger is repairable, and the application range of the plunger is widened.

Description

technical field [0001] The invention relates to a method for manufacturing a ceramic coating, in particular to a method for preparing a supersonic plasma thermal spray coating on an emulsification pump plunger, and belongs to the field of material surface processing. Background technique [0002] Ceramic plungers are mainly used in plunger machinery in the coal, petroleum, chemical, and food industries to replace metal plungers and solve the problem of short equipment life due to poor corrosion resistance and low working temperature resistance of metal plungers. Ceramic plunger products have extremely high wear resistance, corrosion resistance and thermal shock resistance, and their service life is 5 to 10 times longer than that of metal plungers. [0003] There are also some defects in the existing ceramic plunger during use: (1) the surface finish of the plunger is not enough, which increases the frictional resistance of motion, thereby reducing the production efficiency; ...

AI Technical Summary

Problems solved by technology

[0003] There are also some defects in the existing ceramic plunger during use: (1) the surface finish of the plunger is not enough, which increases the frictional resistance of motion, thereby reducing the production efficiency; (2) the ceramic body has cracking phenomenon, and this cracking is It is not easy to detect during the manufacturing process of the ceramic body, but due to the internal stress during the operation of the plunger, the cracks continue to expand and cause the workpiece to be scrapped; (3) The impact of the installation and disassembly process is easy to cause damage to the plunger

At present, although the existing plunger made of ceramic surface layer overcomes the shortcomings of metal plunger and ceramic plunger, but because the preparation of ceramic plunger coating mainly relies on flame spraying and plasma spraying technology, the coating quality is poor, and the spraying The bonding strength between the layer and the matrix is ​​low, it cannot bear alternating loads and impact loads, the porosity is high, and finally it needs to be sealed to meet the requirements of use.

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