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 μm of carbon black and 40 μm 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.