Entropy gradient alloy coating and preparation method thereof

Abstract

The invention discloses an entropy gradient alloy coating and a preparation method thereof. The preparation method comprises the following steps that FeCoCrNi mixed powder and CoCrNi mixed powder are respectively prepared, wherein in the CoCrNi mixed powder, the molar ratio of each element is Co:Cr:Ni=(22-26):(22-26):(22-26), and in the FeCoCrNi mixed powder, the molar ratio of each element is Fe:Co:Cr:Ni=(22-26):(22-26):(22-26):(22-26); the CoCrNi mixed powder is sprayed on the surface of a steel substrate at a high temperature, and the surface of the substrate is partially melted to form a plurality of layers of deposited FexCoCrNi medium entropy alloy transition layers together with CoCrNi; in the spraying process, every time a layer is deposited, the content of Fe in the section of the layer is measured, and spraying is stopped until the molar ratio of Fe in the section of the layer to the alloy ranges from 22% to 26%; and the FeCoCrNi mixed powder and Mo powder are sprayed on the FexCoCrNi medium entropy alloy transition layers at the same time, so that the high-entropy alloy surface coating is formed through deposition, in the spraying process, the powder feeding rate of Mo powder is gradually increased, and finally deposited FeCoCrNiMoy is formed on the outermost side of the surface coating. By setting the entropy gradient, the stability, the mechanical property and the mechanical property of a coating system are greatly enhanced, and the service life of the coating is prolonged.

Description

technical field [0001] The invention relates to the field of surface engineering, in particular to an entropy gradient alloy coating and a preparation method thereof. Background technique [0002] Alloy substrates are widely used in the transportation industry, factories, and large machinery and equipment. With the rapid development of social economy, the frequency of use of alloy matrix is ​​increasing day by day. Sometimes there is a greater risk of corrosion in the working environment of the alloy matrix, and at the same time, mechanical equipment is subject to a greater risk of wear due to friction with the outside world during high-frequency use. At present, most of the research on alloy hard coatings focuses on improving a single performance. There is a lot of research space for obtaining the same system coating with different properties by adjusting the proportion of alloy coating components. Compared with replacing mechanical materials with mature technology, It is...

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Problems solved by technology

However, at present, the problems in the process of depositing high-entropy alloys using atmospheric plasma spraying technology mainly include: 1) Due to the high temperature of the spraying process, the matrix elements dilute the coating, which affects the composition of the coating; 2) There is a gap between the substrate and the coating. Large differences in thermal expansion, which may lead to cracking of the coating

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