Effect of Cr3C2 Addition on Properties of ZrB2-SiC Ceramic

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·m1/2 to 6.7MPa·m1/2. 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.