PRODUCTION OF HIGH-TEMPERATURE PROTECTIVE COATINGS BY MODIFICATION OF HARD-FUSING CARBIDES OF CHEMICAL COMPOUNDS

Progress in the production of heat-resistant alloys, nuclear energy, and industrial high-temperature chemistry necessitates the use of materials capable of withstanding high temperatures, as well as improving the functional and operational characteristics (hardness, strength, wear resistance, corrosion resistance, and service life) of steels and cast iron. Existing compounds have low heat–resistant properties and a limited service life, increasing which is an urgent task that can be solved by modification. Modification is one of the effective and relatively inexpensive ways to change the structure of various industrial alloys. The most promising materials having a long service life and maintaining high hardness over a wide temperature range are carbides of refractory chemical compounds. Various ways of modifying refractory metals with carbides are considered. The characteristics of multilayer and single-layer coatings are presented. The substantiation of the modifying effect exerted on the structure of alloys by refractory chemical compounds of carbides is given. The results of modification of carbon structural steel with tungsten carbide showed an increase in the service life of steel by 70%. It is revealed that a high proportion of the carbide refractory phase grain ensures a small crystal size, which leads to higher hardness and strength of the coating. The analysis of the modified aluminum surface showed the dependence of the properties of the surface layer on the modes of the modification process. It has been established that tantalum carbide is prone to thermal destruction, eliminated by additional alloying. The presented approaches to modifying the surface of metals and alloys can be a solution to the problem of the lack of materials used when heated by high-temperature flows to temperatures exceeding 2000-2500 ° C under the influence of aggressive media.