Oxidation Behavior of ZrB2-SiC Modified Zr3[Al(Si)]4C6 Composites Exposed to Air

Abstract

Abstract The oxidation behavior of Zr3[Al(Si)]4C6-matrix composites reinforced by adjusted content of ZrB2-SiC with fixed molar ratio of 2:1 was investigated. The composites were exposed to air at medium temperatures, and the oxidation kinetics of the composites generally follow a parabolic law. With the ZrB2-SiC content increasing from 0 to 40vol.%, the oxidation weight gain per unit surface area (Δw/s) and oxidation rate constant (k p) of the specimens increase and then decrease at the same oxidation conditions. The high content of ZrB2-SiC is benefit for improving the oxidation resistance of the composites. And, the lowest k p of the composite incorporated with 40vol.%ZrB2-SiC is about 2.43×10−6kg2·m−4·s−1 when oxidized at 1100°C, which is stillhigherthan that of monolithic Zr3[Al(Si)]4C6. In addition, the phase composition and microstructure of oxidation products and the oxidation mechanism of materials were analyzed and discussed.