Low-temperature preparation of ZrC powders using a combined sol–gel and microwave carbothermal reduction method

ZrC powders were synthesized by a combined sol–gel and microwave carbothermal reduction method using zirconium oxychloride and citric acid as starting materials. The effects of firing temperature and n(C)/n(Zr) molar ratio on the synthesis of ZrC powders were studied. The results showed that the optimal n(C)/n(Zr) for the preparation of phase pure ZrC powders was 5.0, and the firing temperature required was 1573 K. This synthesis temperature was 200 K lower than that required by using conventional carbothermal reduction method. Microstructures and phase morphologies of as-prepared ZrC powders were examined by using a field emission–scanning electron microscope (FE–SEM) and a transmission electron microscope (TEM), revealing that the grain sizes of ZrC in the samples prepared at 1573 K for 3 h were about 200–300 nm.