Cavitation-erosion-resistant laser re-melting method of metal ceramic coating through thermal spraying

Abstract

The invention relates to the technical field of cavitation-erosion-resistant coatings, and discloses a method for preparing a cavitation-erosion-resistant coating through a thermal spraying and laserre-melting compound technology. The method comprises the following steps that (1) a metal ceramic composite coating is prepared on a matrix through thermal spraying; and (2), laser re-melting treatment is carried out on the metal ceramic composite coating obtained in the step (1), the surface of the metal ceramic coating is re-melted to form a new structure under high-density energy of lasers, thestructure property of the coating is enhanced after cooling, and the cavitation erosion resistance of the coating can be greatly improved. The method effectively eliminates the problem that ceramic powder deposits on the surface of the matrix through direct laser cladding, the obtained coating is low in porosity, the surface is compact and smooth, the cavitation erosion resistance is excellent, the coating can be widely applied to propellers, water turbine blades and other equipment prone to cavitation damage, the service life of the equipment can be prolonged, the frequency of maintaining the equipment due to cavitation damage is greatly reduced, and the using efficiency of the equipment is improved.

Description

technical field [0001] The invention relates to the technical field of cavitation-resistant coatings, in particular to a laser remelting method for cavitation-resistant thermal sprayed cermet coatings. Background technique [0002] Cavitation erosion is referred to as cavitation erosion, also known as cavitation erosion. Cavitation erosion refers to the formation and collapse of cavitation caused by local pressure changes in the liquid medium under the condition of high-speed multiphase flow. Seriously, the material is continuously impacted by high-pressure and high-speed micro-jet, causing damage to the surface of the metal. In this way, the protective film on the metal surface will be damaged to a certain extent, and the metal particles will be torn to a certain extent. On the surface of the metal, there will be cracks on the surface of the metal, corrosion will occur, and finally the metal surface will become dense and deep. The holes are rough in appearance. Metal cavi...

AI Technical Summary

Problems solved by technology

However, the CrFeAlTiC coating material used in the final coating has poor hardness, and it is difficult to achieve better cavitation resistance.

[0007] Tungsten carbide (WC) has a very high hardness, which is beneficial to improve the cavitation resistance of the coating, but the melting point of WC particles is too high, and it is difficult to form a dense coating of pure WC by existing spraying, sintering and other technologies. Pure WC coatings have defects of micropores and microcracks. Since cavitation pits will grow along the coating defects, pure WC coatings formed by spraying, sintering, etc. are not conducive to anti-cavitation erosion.

Images