INFLUENCE OF BORON NITRIDE IMPURITY ON PHYSICAL AND MECHANICAL PROPERTIES AND WEAR RESISTANCE OF SIALON

Abstract

The kinetics of sintering under a pressure of 10 MPa of β′-sialons with Z = 2.0; 3.0 with an admixture of 3% boron nitride was studied. It was found that the BN admixture reduces the rate of compaction of materials at the initial stage of sintering (in the interval of 0-15 min) by 20-25%. At an isothermal holding time of 60 min, the relative compaction decreases from 0.98-0.99 to 0.95-0.96. The porosity, crack resistance, hardness, and wear resistance of β′-sialons with Z = 2.0; 3.0 with an admixture of 1, 2, 3% boron nitride, obtained by sintering at 1750 °C under a pressure of 10 MPa for 30-60 min, were investigated. It has been established that the lowest wear resistance at closed porosity of the material is provided by sialons with composition Z = 2.0 with an admixture of 1% BN, obtained by pressure sintering for 60 min, and with composition Z = 3.0 with an admixture of 1% BN, obtained by pressure sintering for 30 min. The process of producing sialon products by hot pressing at a pressure of 10 MPa, which work in a friction pair with parts made of heat-resistant steel at temperatures up to 1200 °C, has been developed.