目的 研究不同氧化物添加剂对 SiC-ZrC 涂层 C/ C 复合材料相组成、微观结构和抗氧化性能的影响。 方法 采用包埋法,分别以 Al2O3,B2O3 和 MgO 作为添加剂,制备 SiC-ZrC 涂层 C/ C 复合材料,分析相组成及微观结构,考察复合材料在 1000 ~ 1550 ℃ 静态空气气氛中的抗氧化性能。 结果 以 Al2O3作为包埋添加剂制得的涂层致密,而以 MgO 为添加剂制得的涂层较疏松。 在 1000 ~ 1550 ℃ 的静态空气气氛中,随着氧化温度的升高,以 Al2O3 为添加剂制得的复合材料失重率逐渐减小,在 1550 ℃氧化 1 h 后仅为 1% ;以 B2O3 和 MgO 为添加剂制得的复合材料失重率逐渐增加,在 1550 ℃ 氧化 1 h 后分别达到15% 和 36% 。 结论 与 B2O3 添加剂相比,Al2O3 和 MgO 添加剂更能促进包埋粉料的扩散。 以 Al2O3 作为包埋添加剂制得的 SiC-ZrC 涂层 C/ C 复合材料具有较好的高温抗氧化性能。

Objective To investigate the effect of different oxide additives on the phase composition, microstructure and oxidation resistance of the SiC-ZrC coated C/ C composites. Methods SiC-ZrC coated C/ C composites were prepared by a pack cementation technique with different oxides (Al2O3, B2O3 or MgO) as additives. The anti-oxidation property of the SiC-ZrC coated C/ C composites was also studied in the temperature range between 1000 ℃ and 1550 ℃ in static air. Results The results showed that Al2O3 and MgO additives exhibited better performance in enhancing the diffusion of the embedding powder materials than B2O3 additive. The SiC-ZrC coating prepared with Al2O3 as an additive was more compact than that prepared with MgO as an additive. The weight loss of the SiC-ZrC coated C/ C composites prepared with Al2O3 as an additive decreased gradually with the increasing oxidation temperature in the temperature range of 1000 ~ 1550 ℃ , and the weight loss was about 1% after oxidation at 1550 ℃ for 1 h in air. However, the weight loss of the SiC-ZrC coated C / C composites prepared with B2 O3 or MgO as an additive increased with the increase of the oxidation temperature. After oxidation for 1 h, the weight loss of the composites prepared with B2 O3 and MgO as additives reached 15% and 36% , respectively. Conclusion The SiC-ZrC coated C / C composites prepared with Al2 O3 as an additive had good oxidation resistance at high temperature.