Cermet coatings obtained by electric spark alloying to increase service life of dental instruments

Abstract

The article presents the results of our study of protective cermet coatings obtained by the method of electric spark alloying on a dental instrument (excavator) using SHS (self-propagating high-temperature synthesis) electrodes based on TiC-NiCr. The influence of discharge energy during electric spark alloying on the roughness, thickness, and proportion of the TiC carbide phase in the cermet coating has been established. It has been shown that during electric spark alloying, the material of the used SHS electrode and the surface of the substrate melt, their convective mixing occurs, and during crystallization, coatings are formed that consist of a strengthening phase TiC and iron-based solid solutions: Fe_9.64Ti_0.36, F_1.88C_0.12, and Cr-Ni-Fe-C. It has been found that the maximum size of TiC grains is formed on the surface of the cermet coating, and as they approach the substrate, their size decreases to less than 10 nm. It has been found that the microhardness of the surface of the resulting cermet coatings increased to 6.2 times compared to the microhardness of the original metal base, which was 2 GPa. The results of scanning electron microscopy and energy dispersive analysis of the surface of samples with and without cermet coating before and after corrosion tests are presented. The influence of disinfectants (2 and 100% Trilox, Wendelin, MegaDes-ortho) on the corrosion resistance of samples with and without developed protective cermet coatings at room and elevated temperatures up to 50°C and their exposure for 120 h has been established.