Method for making gradient silicon carbide coating by electrophoresis codeposition

Abstract

The invention discloses a method for making gradient silicon carbide coating by electrophoresis codeposition, which includes the following steps: by ultrasonic processing, suspending liquid A is prepared by silica powder, carbon soot, caking agent polyvinyl butyral, acetone and additive n-butylamine which are mixed according to the mass proportion of 2-16:20:15:100:1; by ultrasonic processing, suspending liquid B is prepared by silica powder, carbon soot, polyvinyl butyral, acetone and n-butylamine which are mixed according to the mass proportion of 16-30:20:15:100:1; by ultrasonic processing,suspending liquid C is prepared by silica powder, carbon soot, polyvinyl butyral, acetone and n-butylamine which are mixed according to the mass proportion of 15-40:10:15:100:1; by ultrasonic processing, suspending liquid D is prepared by silica powder, carbon soot, polyvinyl butyral, acetone and n-butylamine which are mixed according to the mass proportion of 40-70:10:15:100:1; with graphite material as the anode, under a constant potential mode the suspending liquids above are deposited, dried, heated to be between 1200 DEG C and 1600 DGE C, and preserved at the temperature for 20 to 60 minutes. The invention has the advantages of simple process, good thermal-shock resistance and oxidation resistance, controllable coating thickness and uniform coating.

Description

A method for preparing gradient silicon carbide coating by electrophoretic co-deposition technical field The invention relates to a carbon-graphite material surface treatment, in particular to a method for preparing a gradient silicon carbide coating by electrophoretic co-deposition. Background technique In recent years, with the rapid development of high-tech fields such as aerospace and nuclear energy, graphite materials that still have high mechanical strength at 2000 ° C have become one of the hot spots that people pay attention to. However, carbon-graphite materials react with oxidizing gases above 450 °C leading to performance degradation. Anti-oxidation coating is considered to be an effective way to solve its high temperature protection. However, due to the difference in thermal expansion coefficient between the coating and the carbon matrix material, there is a large thermal stress in the coating, which leads to the weak combination of the coating and the substra...

AI Technical Summary

Problems solved by technology

Although this method can theoretically prepare a gradient coating, the equipment is complicated and the cost is high; and it is difficult to ensure that the suspension is uniform, resulting in poor operability