Long-time ablation protection of carbon/carbon composites with different-La2O3-content modified ZrC coating |
| |
Authors: | Yujun Jia Hejun Li Xiyuan Yao Jiajia Sun Zhigang Zhao |
| |
Affiliation: | State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an, 710072, PR China |
| |
Abstract: | Long time oxidation protection at ultra-high temperatures or ablation protection has been a choke point for C/C composites. In this study, long time ablation protection of different-La2O3-content (5–30 vol.%) modified ZrC coating for SiC-coated carbon/carbon (C/C) composites was investigated. Results showed that ZrC coating with 15 vol.% La2O3 had good ablation resistance and could protect C/C composites for at least 700?s at 2160 °C. A high-thermal-stability and low-oxygen-diffusivity oxide scale containing m-ZrO2 particles and molten phases with La0.1Zr0.9O1.95 and La2Zr2O7 was formed during ablation, offering the ablation protection. La could erode grain boundaries of ZrO2 to refine ZrO2 by short-circuit diffusion and m-ZrO2 particles were retained due to less bulk diffusion than grain-boundary diffusion of La into ZrO2. The erosion resulted in the formation of molten phases containing fine nano-ZrO2, which served as viscous binder among m-ZrO2 particles and crack sealer for the oxide scale. |
| |
Keywords: | Coating Carbon/carbon composites Lanthanum oxide Long-time ablation |
本文献已被 ScienceDirect 等数据库收录! |