This chapter examines the regularities of structural changes of carbon steel with selffluxing coating in the process of thermal treatment with application of various technologies and the development of recommendations on the optimization of modes of technological process. Coatings have been knurled by means of plasma method by powder alloy Ni-Cr-B-Si with thickness 0.3–0.9 mm, applying plasmotron with sectional interelectrode insertion, which has been developed in the Thermal Physics Institute of the Siberian Division of the Academy of Sciences of the USSR. Depending on temperature-time parameters in the result of heating the coating can be sintered partially or completely, it may have solid-liquid state or may be fused. Moreover, the basic structure has been varied. The final structure of compositional material received at thermal treatment depends on conditions of the next cooling. At thermal treatment by dipping of products in salt bath the best results have been received at heating of coatings up to solid-liquid state.