Abstract
The oxidation of silicon boride (SiB4) powder at high temperatures was investigated in order to determine the possibility of its high-temperature utility. SiB4 powder with an average particle size of about 10μm was used in this experiment. The sample oxidized at 200 to 1100°C for 5min to 50h in air; the weight changes were measured to estimate the oxidation resistance. The oxidation of sample, at the short oxidation time of 5min, started at 500 to 600°C, and weight gain changes with increasing oxidation temperature. The sample at the oxidation time of 0.5 to 1h, exhibited weight gain change with increasing oxidation temperature, and then the oxidation saturated at 900°C. On the other hand, at the oxidation time of 10h, it had the maximum value of the weight gain at 600°C, after that the weight gain monotonically decreased with increasing oxidation temperature. SiB4 is oxidized to vitreous SiO2 and B2O3 at about 700°C. The B2O3 of oxidation product vaporized above at 900°C. The vitreous SiO2 transformed into the cristobalite.
