Phase composition of SiC-ZrO2 composite materials synthesized from zircon doped with La2O3

A study was carried out to determine the optimum parameters for synthesis of SiC-ZrO2 composite materials by carbothermal reduction of zircon. Test samples were prepared by mixing average mesh size of less than 30 mu m of carbon black and 40 mu m of zircon with C/ZrSiO4 mass ratio of 0.2 and the extra addition amount of La2O3 was 0, 1 wt.% and 2 wt.%. Prepared samples were subjected to the carbothermal reduction process at temperatures of 1723, 1753, 1773 and 1803 K for 4 h, respectively. The carbothermal reduction process was conducted in an atmosphere controlled tube furnace at an argon flow of 1.5 L/min. All products were examined by X-ray diffraction (XRD) to determine the transformation. The results showed that the best transformation of SiC-ZrO2 composite materials occurred at 1803 K for 4 h with the amount of 2 wt.%La2O3.