The oxidation kinetics of silicon hexaboride (SiB6) was studied at different partial pressures of oxygen. The specific weight gain was measured at 1173 K, 1223 K, and 1273 K for $$ P_{{{\text{O}}_{2} }} $$PO2 = 0.1, 0.23, and 0.33 atm using thermogravimetric analysis. The conventional empirical expressions for oxidation were observed at all selected oxygen partial pressures and temperatures. The structural characterization of the oxidation product was characterized using XRD and FT-IR, with SiB6, SiO2, B, and amorphous B2O3 observed after oxidation for 25 hours. The oxidation surface morphology was also characterized to obtain the oxidation product size, ranging from 4.54 to 24.69 µm with increasing $$ P_{{{\text{O}}_{2} }} $$PO2 and temperature. The diffusional activation energy for the oxidation process was also calculated from the empirical constant, obtained from the mathematical fitting of the specific weight gain with time. The oxidation activation energies for SiB6 are 250.72, 235.64, and 232.65 kJ/mol at $$ P_{{{\text{O}}_{2} }} $$PO2 = 0.1, 0.23, and 0.33 atm, respectively.

中文翻译：

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氧分压和温度对SiB6氧化行为的影响

在不同的氧分压下研究了六硼化硅 (SiB6) 的氧化动力学。使用热重分析在 1173 K、1223 K 和 1273 K 下测量比重量增加，其中 $$ P_{{{\text{O}}_{2} }} $$PO2 = 0.1、0.23 和 0.33 atm。在所有选定的氧分压和温度下观察到氧化的常规经验表达式。使用 XRD 和 FT-IR 表征氧化产物的结构特征，在氧化 25 小时后观察到 SiB6、SiO2、B 和无定形 B2O3。氧化表面形态也被表征以获得氧化产物尺寸，范围从 4.54 到 24.69 µm，随着 $$ P_{{{\text{O}}_{2} }} $$PO2 和温度的增加。氧化过程的扩散活化能也由经验常数计算，该常数是从特定重量增加随时间的数学拟合获得的。SiB6 的氧化活化能分别为 250.72、235.64 和 232.65 kJ/mol，在 $$ P_{{{\text{O}}}_{2} }} $$PO2 = 0.1、0.23 和 0.33 atm 时。