Synthesis of SiC-TiC composite powders by carbothermal reduction and their sintering behavior

摘要

SiC-TiC composite powders were synthesized in Ar at 1300 ～ 1700 °C by carbothermal reduction using TiO2, carbon black and silica sol as the starting materials. The synthesized products were characterized by XRD and SEM. The ignition loss was calculated to determine the degree of the carbothermal reaction. The results show that the SiC-TiC composite powders synthesized at 1600 °C for 1 h are composed of round-like and plate-like particles and a small amount of whiskers with a size of 5O ～ 100 nm. The influence of a AlN-Y2O3 additive on the sintering behavior of the SiC-TiC composite powders was investigated by microstructural observation and Rockwell hardness testing. The SiC-TiC composites with 1O vol% AlN-Y2O3 hot pressed at 1900 °C under 25 MPa possess a relative density of 98.9% and Rockwell hardness of 93.2HRA.