Storozhenko M. Development of wear-resistant TiB2-SiC ceramic, metal-ceramic materials and spark-alloying coatings.

Thesis is devoted to the development of TiB2-SiC ceramic, TiB2-20%SiC cermets with Ni-20%Cr metallic bond and alloy-spark coating based on the developed ТБКНХ cermets. TiB2-SiC ceramic materials have heterogeneous structure with uniform distribution of carbide particles in titanium boride. At friction under high speed and load steel material becomes deformed and transmits on ceramic surface. At the same time Fe2O3, Fe3O4 oxide films are formed on the friction surfaces. These films prevent damages of friction surfaces and provide high tribotechnical characteristics. On the base of researched dependences of wetting and contact interaction of TiB2-SiC with nickel and nickel-based alloys it has been established that Ni-20mas.%Cr is the optimal metal bound. The technological parameters of (TiB2-SiC)-(Ni-20mas.%Cr) cermets manufacturing were optimized. The structure of new cermets is heterogeneous and consists of titanium boride grains and metal bond that represents silicon solution in nichrome. It is possible by the amount of metal bond content to influence on oxide films thickness in cermets and to operate on the intensity of developed cermets wear process. As a result of steel electric-spark alloying by ТБКНХ electrodes, hardened layer is formed. It represents the matrix of iron-based solid solution strengthened by titanium boride particles. The developed modified layers have high tribotechnical characteristics and improve wear resistance of 30ХГСА steel by 3-4 times.