Research of the Influence of Conditions of D-gun Spraying on Properties of Tungsten and Chromium Carbides Coatings

The influence of conditions of D - gun spraying on properties of coatings from tungsten and chromium carbides are investigated. It is proved that the formation of structure and properties of D-gun spraying coatings is determined by character and intensity of physical and chemical transformations in powder particles and their interaction with the environment at all stages of technological process, including manufacture and preparation of powder, as well as the formation of interparticle connections. It is shown that in the development of technological processes, it is necessary to consider and provide optimal conditions for conductive transformations and phenomena, which have a decisive influence on the structure and properties of applied coatings. For this can be used regulation of combustible mixture composition, geometry, and dimensions of a barrel, conditions of powder introduction into the barrel, a single dose of powder, spraying distance, cyclogram of the working cycle, and other technological parameters. In the design of technologies and equipment for D-gun spraying of coatings from tungsten and chromium carbides, special attention should be paid to the formation of a local powder cloud in combustion detonation chamber, as well as its location in chamber taking into account the spraying distance. D-gun spraying can be used to obtain high-quality coatings from fine powders of tungsten carbide-cobalt. Still, it is necessary to design specialized devices for dosing and local introduction of fine powders into the combustion detonation chamber.