Hot spraying ceramic powders include oxide, carbide, boron, nitride and silicide, which are crystalline or non-crystalline compounds of metallic elements and non-metallic elements. Ceramic coating has the characteristics of high melting point, high hardness and good wear resistance, corrosion resistance and high temperature stability. However, the coating process is complex, the cost is higher, and the coating surface is prone to crack, the thermal fatigue performance is not as good as the metal coating. Moreover, the coating has poor toughness and can not be used to withstand large impact load. Currently, the commonly used ceramic coatings are A12O3, TiO2, Cr2O3, ZrO2, WC, TiC, Cr3C2, TiB2, etc., which are usually prepared by plasma spraying, flame spraying, HVOF and explosive spraying technology.

Plasma spraying A12O3-40% TiO2 and Cr2O3 sliding friction and wear properties of ceramics powder coating is pointed out that the wear resistance of coating Cr2O3 higher than A12O3-40% TiO2 coating, the wear mechanism of Cr2O3 coating are mainly abrasive wear and tear, under the large load, Cr2O3 coating wear characteristics of brittle fracture. The abrasion mechanism of a12o3-40% TiO2 coating is mainly characterized by plastic deformation and laminar stripping. Study of A12O3 plus TiO2 and NiCrAlY composite ceramic coatings, due to the melting of TiO2 and A12O3 formed a certain degree of miscibility, can decrease the coating porosity, further improve the strength, toughness and wear resistance of the coating.

Lin et al. studied the wear and tear characteristics of plasma spraying multi-layer metal and ceramic coating. The thermal spraying sequence was first sprayed on the base with NiCr on the bottom layer, then the nicr-cr2o3 transition layer of different proportions, with a surface of 100% Cr2O3. It is found that the transition layer of suitable metal and ceramic ratio can improve the wear resistance of the coating. The main wear mechanism of coating is brittle fracture, abrasive wear, adhesion and oxidation wear.

Metal and the excellent properties of ceramic materials have their unique and significant performance weakness, how to put the metal and ceramic materials combine their advantages performance, has been the direction of materials science and engineering research. Metal ceramic composite hot spraycoating technology, namely in the plastic substrate evenly distributed on the particle shape and size of the appropriate size ceramic phase, successfully integrate the advantages of metal and ceramic, the preparation of both strength and toughness, metal and ceramic advantages of high temperature resistance, wear resistance, corrosion resistance of composite materials, greatly expanded metal materials and ceramic materials, their application scope, in aviation, aerospace, chemical, mechanical, electrical and other industrial applications successfully. The most widely used metal ceramic coatings in industry are: Cr3C2- NiCr, WC- Co. HVOF, plasma and explosive spray are used in the process.

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