Rapid preparation of dense Gd2Zr2O7 nano-grain ceramics by microwave sintering in air

Abstract

Gd2Zr2O7 nano-grain ceramics with high densities (>90%) and small average grain sizes (66–96 nm) were successfully fabricated for the first time by the fast microwave pressureless sintering method (processing time: 10–90 min). The sintering behavior and microstructural evolution of fluorite structure Gd2Zr2O7 nano-grain ceramics were investigated from 1100 °C to 1300 °C. Comparative analyses were conducted to unveil the influence of temperature and holding time on densification. The results suggest the optimized conditions for sintering dense nano-grain ceramics (66–96 nm) can be achieved at relatively low temperatures (<1250 °C) and long sintering time (60–90 min), or at high temperatures (>1250 °C) and short sintering time (10–60 min). As a demonstration, dense Gd2Zr2O7 ceramics with average grain size of 66 nm were prepared for the first time by rapid microwave pressureless sintering.