INFLUENCE OF STRUCTURAL-PHASE CONDITION ON THE MECHANICAL-TRIBOLOGICAL PROPERTIES OF Ti_3SiC_2 COATINGS OBTAINED BY THE DETONATION METHOD

摘要

The article provides the results of the research of the structure and properties of powder coatings based on titanium carbosilicide Ti_3SiC_2 obtained by detonation spraying on the surface of tool steel U9/Y9 (equivalent to N9). Micro-indentation methods and abrasive wear tests for mechanical and tribological properties of Ti_3SiC_2 based coatings were conducted. The microstructure of the coating has a layered structure. The border between the coating and the base has a characteristic crinkled appearance. It was determined that the phase composition of the coatings changes during detonation spraying is a result of the decomposition of Ti_3SiC_2 powder into titanium carbide and titanium carbosilicide (secondary phases). Selected consolidation conditions ensure the formation of a Ti_3SiC_2/TiC composite material. The influence of the second phase content (TiC, TiO_2) on the properties of coatings was studied. Studies of the microhardness of samples with coatings showed that, in the entire range of annealing temperatures, the microhardness of the Ti_3SiC_2/TiC composite material increases compared to the coating before annealing. It was found that the maximum microhardness of the Ti_3SiC_2/TiC composite material after annealing at a temperature of 800 °C is explained by an increase in the content of the Ti_3SiC_2 phase. It was established that, during detonation spraying of Ti_3SiC_2 powders, a coating with a higher microhardness and wear resistance is formed.