化学气相沉积ZrC陶瓷涂层的微观结构和抗烧蚀性能

Microstructures and Ablative Properties of ZrC Coating by Chemical Vapor Deposition

为了提高碳/碳(C/C)复合材料的抗烧蚀性能,在C/C基体上成功制备了碳化锆(ZrC)高温抗烧蚀涂层。用常压化学气相沉积法,前驱体选用ZrCl4+C3H6+H2+Ar体系。通过调节C3H6的流量,制得3种碳锆原子比的ZrC陶瓷涂层(ZrC1.0+C,ZrC1.0,ZrC0.7)。分析了不同锆碳比ZrC涂层的相组成和形貌差异,研究了锆碳比对ZrC陶瓷涂层的烧蚀性能的影响。结果表明,3种ZrC涂层都可有效提高C/C复合材料的抗烧蚀性能,但由于微观结构特征不同,3种涂层显示不同的烧蚀性能和烧蚀机制。其中,ZrC0.7涂层试样烧蚀后,表面形成致密的氧化物层,烧蚀性能最佳,烧蚀240 s后质量烧蚀率和线烧蚀率分别为1.1×10-4 g/cm2.s和0.3×10-3 mm/s。

To improve the anti-ablative properties of carbon/carbon （C/C） composites, the controlled preparation of zirconium carbide （ZrC） coatings of superstoichiometric, stoichiometric, and substoichiometric compositions has been a chieved utilizing zirconium tetrachloride and propene precursor gases in an atmospheric pressure chemical vapor deposition system. The ablative properties of coated samples were tested in an oxy-acetylene torch system. The phase compositions and morphological features of the coatings were investigated pre- and post test. The results show that all types of ZrC coatings can protect C/C substrate from ablation. Due to individual microstructure feature, ZrC1.0 ＋ C, ZrC1.0 and ZrC0. 7 coatings have different ablation resistance and mechanisms. Of the three types of coatings, ZrC0.7 coating with microaggregatelike textures and fine grains acts as the best anti-ablation barrier which can reduce mass and linear ablation rates to 1.1 × 10 ^-4 g/cm^2 · s and 0.3 × 10^ -3 mm/s after 240 s＇ ablation.