Method for forming ceramic core aluminum oxide coating through supersonic plasma spraying

Abstract

The invention discloses a method for forming a ceramic core aluminum oxide coating through supersonic plasma spraying. The method comprises the following steps that S1, nano Al2O3 ceramic powder is prepared, wherein the particle size of the ceramic powder is 5-22 micrometers, and the purity of the ceramic powder is not lower than 99%; S2, NiCrA powder is prepared to serve as a transition layer material, wherein the particle size of the NiCrA powder ranges from 15-45 micrometers, and the purity of the NiCrA powder is not lower than 99%; S3, the ceramic powder and the transition layer material are dried; S4, the transition layer material is sprayed on the surface of a ceramic core by adopting supersonic flame to serve as a bonding layer; and S5, the ceramic powder is sprayed on the surface of the bonding layer by adopting supersonic plasma. The aluminum oxide coating prepared through the method has the advantages of being higher in compactness, higher in hardness, better in bonding strength, resistant in wear, resistant in high temperature, and the like, and excellent in comprehensive performance.

Description

technical field [0001] The invention relates to the technical field of coating preparation, in particular to a method for forming an aluminum oxide coating of a ceramic core by supersonic plasma spraying. Background technique [0002] The proposal of "Research on Preparation Technology of Ceramic Core Alumina Coating" is based on the urgent need for high-performance ceramic cores in national aero-engine and gas turbine blade directional solidification precision casting. [0003] Based on the idea of ​​developing a two-component ceramic core, research the coating preparation technology for forming an alumina high-temperature resistant layer on a silicon oxide substrate, and explore the method for directional solidification of hollow turbine blades with silicon oxide as the substrate and alumina as the surface high-temperature resistant layer The preparation process of the two-component ceramic core solves the problems of insufficient high-temperature strength of the existing ...

AI Technical Summary

Problems solved by technology

[0003] Based on the idea of ​​developing a two-component ceramic core, research the coating preparation technology for forming an alumina high-temperature resistant layer on a silicon oxide substrate, and explore the method for directional solidification of hollow turbine blades with silicon oxide as the substrate and alumina as the surface high-temperature resistant layer The two-component ceramic core preparation process solves the problems of insufficient high-temperature strength of the existing silica-based ceramic core, easy chemical reaction with the alloy liquid, and difficulty in removing the core from the alumina-based ceramic core

[0004] At present, the alumina coating is prepared by atmospheric plasma or low-pressure plasma spraying technology. The coating prepared by the former has high porosity, which affects many properties of the coating such as wear resistance, corrosion resistance, and electrical insulation; the latter has high preparation costs and low production efficiency. Low

In addition, traditional ceramic materials have the disadvantages of high brittleness and poor toughness, and are easily impacted by high-speed particles to cause cracks and brittle fracture failures.

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