621.762A system approach to controlling the quality of detonation-sprayed coatings is developed. It includes such stages as selecting powder characteristics and gas composition, forming a gas-powder mixture, adjusting the parameters of two-phase pulse flow, and ensuring contact interaction needed to form the coating that depends on the material and preset service properties of the layer sprayed.Modern engineering, the reliability and life of machines and mechanisms, and the performance of equipment considerably depend on the development and application of various protective coatings. They impart products with a unique combination of properties that cannot be achieved with traditional structural materials.One of the promising methods of protection against wear and hot corrosion in power engineering, aircraft, motor-car, and turbine construction, petrochemistry, and metallurgy is detonation spraying (DS). Its advantages are high bonding strength (100-180 MPa) between the coating and substrate, high density of the protective layer (porosity less than 1%), and the possibility of spraying almost any material on any substrate without change in the properties of the base material. The high performance of detonation coatings makes it possible to extend considerably (five-to ten-fold or, in some cases, by a factor of 20 to 30) the life of units and mechanisms.Research on detonation spraying was initiated by Grigorii Samsonov at the Institute for Problems of Materials Science, Academy of Sciences of the Ukrainian SSR, in the early sixties. In 1972, he also initiated continuation of the research at the Leninskaya Kuznitsa Central Design Bureau, which puts scientific achievements into practice at shipbuilding plants [1][2][3][4].This paper is dedicated to the memory of Grigorii Samsonov, a great scientist and teacher. The time is now ripe to generalize and analyze the accumulated theoretical and experimental data to lay the scientific foundation of the DS process, which would allow controlling the properties of coatings, and to develop technologies and industrial equipment for spraying coatings of various purposes. The modern theory of thermal-sprayed coatings is based on the studies initiated by M. Kh. Shorshorov, V. V. Kudinov, Yu. A. Kharlamov under the guidance of academician N. I. Rykalin and continued by V. I. Pokhmurskii, Yu. S. Borisov, I. L. Kupriyanov, and E. A. Astakhov at the A. A. Baikov Institute of Metallurgy.An analysis of the results from the studies shows that besides a number of common features associated with the nature of the process and material (lamination, discreteness, inhomogeneity of coatings, presence of pores and oxide inclusions, various boundaries), thermal-sprayed coatings obtained by different methods also show significant differences associated with technological features of the process. Among them are differences in the degree of oxidation of the sprayed material, in the phase composition and properties of the coating, and in the changes of the mechanical properties of the substrate. In thi...
