ABSTRACT The oxidation and its effect on room temperature flexural strength were examined in hot-pressed 3 vol.-% La2O3-doped HfB2-20 vol.-% SiC composite exposed to air at 1400°C and 1500°C, respectively, for up to 100 h. The major oxidation products consisted of SiO2 (α-cristobalite), La2Si2O7, HfO2 and HfSiO4 regardless of oxidation temperature. However, the morphology of the microstructure of the oxidised surfaces was shown to be dependent on oxidation temperature. In addition, it was found that the room temperature flexural strength of the composite degraded after oxidation and the degradation of strength depended on oxidation time at temperature and oxidation temperature. The strength retention displayed by composite after 100 h of oxidation at 1400°C and 1500°C was ∼83% and ∼74%, respectively.

中文翻译：

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含 La2O3 添加剂的 HfB2−SiC 复合材料的氧化和强度保持

摘要 在分别暴露在 1400°C 和 1500°C 空气中的热压 3 vol.-% La2O3 掺杂 HfB2-20 vol.-% SiC 复合材料中，研究了氧化及其对室温弯曲强度的影响。到 100 小时。无论氧化温度如何，主要氧化产物包括 SiO2（α-方石英）、La2Si2O7、HfO2 和 HfSiO4。然而，氧化表面的微观结构的形态被证明取决于氧化温度。此外，发现复合材料的室温弯曲强度在氧化后降低，强度的降低取决于在温度和氧化温度下的氧化时间。在 1400°C 和 1500°C 下氧化 100 小时后，复合材料显示的强度保持率分别为~83% 和~74%。