KINETIC MICROHARDNESS MEASUREMENTS OF SIALON-BASED CERAMICS

The conventional procedure of microhardness testing consists in applyi ng a fixed load on an indentor and measuring the square of the indent under the microscope. The method of kinetic microhardness (registratio n of the depth of penetration of an indentor as a function of load) re veals new features of mechanical characteristics of the surface of bri ttle materials. The investigated sialon-based ceramics demonstrate unr elaxed hardness from 5-13 GPa and elastic relaxation up to 60%-63%. An alysis 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 investi gated materials was found to be 2, varying from 0.92-2.10.