Cr₃C₂添加剂对ZrB₂-SiC复合陶瓷性能的影响

ZrB₂-SiC ceramics with different Cr₃C₂ contents (0%, 5%, 10%, 20%, volume fraction) were successfully prepared by spark plasma sintering(SPS) process at 1700℃. The effect of Cr₃C₂ content on mechanical properties and the oxidation behavior of ZrB₂-SiC ceramics at 1500℃ was investigated. The results show that the internal defects of ceramics reduce due to the reaction between Cr₃C₂ and the substrate phases during SPS sintering. With the increase of Cr₃C₂ content (from 0% to 20%), the hardness increases from 12.6GPa to 15.8GPa and the fracture toughness increases from 4.9MPa•m^1/2 to 6.7MPa•m^1/2. By adding 10%Cr₃C₂, the bending strength at room temperature can be improved to 708MPa, and the mass gain of ceramic after being oxidized for 10h at 1500℃ in air is less than 10mg/cm², the thickness of the oxidation layer reaches a minimum value of 160μm, which indicates that the oxidation resistance significantly enhances.