Oxidation of ZrB₂–SiC‐Graphite Composites Under Low Oxygen Partial Pressures of 500 and 1500 Pa at 1800°C

Abstract

The oxidation behavior of ZrB 2 -SiC-graphite composites under low oxygen partial pressures of 500 and 1500 Pa at 1800°C was investigated. The phase composition and microstructure of the oxidized scale were characterized using TEM, SEM, XRD, XPS, EDS. The analytical results indicated that a low oxygen partial pressure had a remarkable effect on the oxidation mechanism of ZrB 2 -SiC-graphite composites. When oxidized at 1500 Pa, the oxidation kinetics was controlled by the rate of oxygen diffusion into the composite. When the composite was oxidized at 500 Pa, control of the oxidation kinetics changed from the rate of oxygen diffusion to the rate of the oxidation reaction. The rate of oxidation decreased with decreasing oxygen partial pressure. Higher partial pressures of oxygen resulted in less oxidation resistance by the ZrB 2 -SiC-graphite composites.

ZrB2 particles reinforced glass coating for oxidation protection of carbon/carbon composites

“…The following reactions occur during the oxidation in the ZrB 2 /SiO 2 coated SiC-C/C composites [29,30]. (1)…”