Oxidation Resistance Analysis of Zirconium Carbide Sintered by Hot-pressing

A self-fabricated ZrC powder prepared by self-propagating high-temperature synthesis method was used as a raw material to investigate its oxidation mechanism and oxidation dynamics of hot-press sintered bulk. The results show that ZrC becomes oxidation at 200 , and the main product is ZrC_xO_1-x in the temperature range of 200–450 in air. An intermediate product of Zr₂O is formed at 500 , and almost completely transferred to ZrO₂ at 1 000 . The results of the oxidation dynamics of hot-press sintered bulk indicate that a dense coating layer of ZrC_xO_1-x can be formed within 450 . And the coating layer keeps little change with time under this temperature while the x attains 0.42 in the ZrC_xO_1-x product on the surface of the coating layer. The sintered bulk would be broken when the temperature increases due to the stress caused by the crystal lattice change from ZrC_xO_1-x to Zr₂O and ZrO₂. The resistance of the coating layer increases from 37 to 690 μΩcm with the x increase.