无机材料学报

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C/SiC-BN复合材料的制备及氧化行为

姜灵毅1,2, 庞生洋2, 杨超1, 张悦1, 胡成龙2, 汤素芳2   

  1. 1.沈阳工业大学 材料科学与工程学院,沈阳 110870;
    2.中国科学院金属研究所,沈阳 110016
  • 修回日期:2023-12-18 接受日期:2024-01-21 出版日期:2024-02-22 网络出版日期:2024-02-22
  • 作者简介:姜灵毅(1999-),男,硕士研究生.E-mail: lyjiang22h@imr.ac.cn
  • 基金资助:
    国家自然科学基金(52272075, U20A20242)

Preparation and Oxidation Behaviors of C/SiC-BN Composites

JIANG Lingyi1,2, PANG Shengyang2, YANG Chao1, ZHANG Yue1, HU Chenglong2, TANG Sufang2   

  1. 1. School of Materials Science and Engineering, Shenyang University of Technology, Shenyang 110870, China; 2.Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
  • Revised:2023-12-18 Accepted:2024-01-21 Published:2024-02-22 Online:2024-02-22
  • About author:JIANG Lingyi (1999-), male, Master candidate. E-mail: lyjiang22h@imr.ac.cn
  • Supported by:
    National Natural Science Foundation of China(52272075, U20A20242)

摘要: C/SiC复合材料作为一种高温结构材料,在航空航天热防护领域具有广泛的应用前景。然而,该材料中低温抗氧化性能相对较差,制约了其在更广泛领域的应用。本研究采用料浆抽滤工艺,通过调节料浆中陶瓷含量在纤维增强体中引入不同含量的抗氧化组元BN,再通过反应熔体渗透法制备出了C/SiC-BN复合材料。系统研究了不同BN含量对复合材料结构组成及抗氧化行为的影响,并对相关氧化机理进行了分析。研究结果表明:引入BN颗粒的显著降低了C/SiC的开口孔隙率,并明显提高了C/SiC的起始氧化温度。引入BN的质量分数为预制体3%(B3样品)时,C/SiC-BN复合材料的抗氧化性能最优,其在900 ℃、1200 ℃、1500 ℃静态氧化1 h的质量变化率分别为0.009%、-0.301%、-0.596%,显著优于C/SiC。900 ℃氧化时,C/SiC-BN复合材料主要经历C相和BN相的氧化,以O2扩散反应控制的缓慢失重为主;1200 ℃氧化时,C相和BN相氧化速率加快,SiC开始发生显著氧化,B2O3、硼硅酸盐和SiO2等氧化产物的生成减缓了O2的扩散反应,减小了基体碳的损伤;1500 ℃氧化时,SiC氧化速率加快, 生成的SiO2在复合材料表面形成的连续氧化膜阻碍了O2的向内扩散。B2O3、CO等气体产物的溢出及SiO2的持续生成主导了整个氧化过程。B3样品的抗氧化性能较好, 1500 ℃氧化后强度保持率最高,达到52%。

关键词: 料浆浸渍, C/SiC, BN, 微观结构, 氧化行为

Abstract: As thermal structural materials operating at high temperatures, C/SiC composites have extensive applications for thermal protection systems in aerospace vehicles. However, the limited antioxidant performance of these composites at low and medium temperatures restricts their utilization in diverse fields. In this work, an improved slurry filtration technique was carried out to introduce antioxidant component BN with different contents into the carbon fiber felts by adjusting the ceramic content in the slurry, and then densify the felts to prepare C/SiC-BN composites using reaction melt infiltration. The effects of BN contents on the composition, microstructure and oxidation behavior of the composites were systematically studied, and the relevant oxidation mechanisms were analyzed. The results indicate that the introduction of BN particles significantly reduces the open porosity of C/SiC and enhances the initial oxidation temperature of C/SiC. The optimum mass fraction of BN to carbon fiber felt ratio is 3%(sample B3), and the corresponding mass losses in static air at 900 ℃, 1200 ℃ and 1500 ℃ for 1 h are 0.009%, -0.301%, and -0.596%, respectively. At 900℃, the mass change is dominated by slow weight loss controlled by O2 diffusion and the oxidation of the C and BN. At 1200℃, the oxidation rates of C and BN phases become more severe and SiC begins to undergo significant oxidation. The formation of oxidation products such as B2O3, borosilicate, and SiO2 slows the diffusion of O2 and reduces the damage of carbon. At 1500 ℃, the oxidation rate of SiC is accelerated. The continuous oxidation film formed by the generated SiO2 retards the inward diffusion of O2, and the overflow of gas products such as B2O3 and CO and the continuous formation of SiO2 dominate the oxidation process. Due to the good oxidation resistance, the strength retention rate of sample B3 is up to 52% after oxidation at 1500 ℃.

Key words: slurry impregnation, C/SiC, BN, microstructure, oxidation behaviors.

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