KINETIC MICROHARDNESS MEASUREMENTS OF SIALON-BASED CERAMICS

The conventional procedure of microhardness testing consists in applying a fixed load on an indentor and measuring the square of the indent under the microscope. The method of kinetic microhardness (registration of the depth of penetration of an indentor as a function of load) reveals new features of mechanical characteristics of the surface of brittle materials. The investigated sialon-based ceramics demonstrate unrelaxed hardness from 5-13 GPa and elastic relaxation up to 60%-63%. Analysis of the surface layers was made in ranks of the Meyer's equation. The value of the coefficient, N (Meyer's index), of the best investigated materials was found to be 2, varying from 0.92-2.10.