Microstructure evolution and densification kinetics of Al2O3/Ti(C,N) ceramic tool material by microwave sintering

The microstructure evolution and densification kinetics of Al2O3/Fi(C,N) ceramic tool material during microwave sintering were studied. The density and grain growth significantly increases at the temperatures higher than 1400 degrees C. The calculated kinetics parameter n indicates that volume diffusion is the main densification mechanism when the sintering temperature is below 1300 degrees C, while grain boundary diffusion plays a leading role in the densification process when the sintering temperature is higher than 1300 T. The grain growth activation energy of Al2O3/Fi(C,N) composite is 48.82 KJ/mol, which is much lower than those of monolithic Al2O3 in the microwave sintering and conventional sintering. The results suggested that the Al2O3/Fi(C,N) ceramic tool material with nearly full densification and fine grains can be prepared by two-step microwave sintering. (C) 2016 Elsevier Ltd. All rights reserved.