Conditions of interaction of materials in gas thermal spraying of metallized oxide powders on AK-4 alloy

Conclusions

The analysis made from the viewpoints of thermodynamics and the quasichemical theory of the formation of bonds in gas thermal spraying indicates the unquestionable advantages of aluminum oxide composites and the significant role of surface oxide films in the creation of reliable thermal protection coatings on aluminum alloys. It is most desirable to obtain ZrO₂ base coatings and a change in the nature of the oxide film on the surface of AK-4 alloy by preliminary formation of a NiO sublayer on it. The use for spraying of metallized oxide powders substantially increases the energy of contact interaction of the materials on the base. The components of the metallized powders interacts with the formation of types Zr-Al and Zr-Al-Ni oxidized phases. The depth of mutual diffusion of the elements of the coating and the base is 0.5–3 um. The adhesion strength of the optimum composition thermal protection coating with the surface of AK-4 alloy reaches 20–25 MPa.