LIAO Zijian 1, 2, ZOU Yangjun 2, 3, HUANG Xiaozhong 2, 3, WANG Chunqi 2, 3
(1. School of Aeronautics and Astronautics, Central South University, Changsha 410083, Hunan, China; 2. Key Laboratory for Advanced Fibers and Composites of Hunan Province, Central South University, Changsha 410083, Hunan, China; 3. Powder Metallurgy Institute, Central South University, Changsha 410083, Hunan, China)
Abstract: The presence of oxygen has long been considered to be the main factor for the reduction in antioxidation capability and thermal stability of silicon carbide fibers (SiCf). Herein, we demonstrated that the introduction of beryllium can increase the thermo-oxidative stability of SiCf with relative high content of oxygen. According to chemical analysis results, formula of the SiCf fibers containing beryllium (SiCf(OBe)) was calculated to be SiC2.16O0.28Be0.02H9.39. X-ray diffraction results indicated that the SiCf(OBe) consisted mainly of β-SiC with an average grain size of 1.5 nm, along with SiCxOy and graphite carbon. After sintering at 1400 ℃ for 2 h in Ar, the SiCf(OBe) exhibited an average tensile strength of 1.2 GPa, with an increase by 70%. After annealing at 1300 ℃ for 2 h in the air, the SiCf(OBe) still had strength retention of 50%, much higher than that (20%) of the common SiCf.
Key words: silicon carbide fiber; beryllium; curing; high temperature resistance; oxidation resistance