Ceramic Compacts Based on Sintered ZrO₂ Nanopowder

Abstract

Ceramic based compacts used in tool bits are of fundamental importance for high speed machining operations. Pure ceramic, however, is too brittle. Therefore, conventional hardmetal cermets such as WC-Co are commonly used, in spite of thermal limitations due to the metallic matrix. The present work investigates the properties of sintered ZrO2 nanopowder, stabilized with Yb2O3, as a tough enough pure ceramic with high thermal resistance for tooling compacts. Sintering of ZrO2 nanopowder with particle size below 0.1µm in presence of 2-3% of Yb2O3 was conducted under pressure of 180 to 300 MPa and temperatures from 1500 to 1600°C, during 40 to 60 minutes. Both the density and strength pass through maximum values with temperature and processing time. Strength of 9.500 MPa and hardness of 17.5GPa as well as fracture toughness of 12.5MPa.m1/2 were obtained