反应温度对水热改性炭/炭复合材料抗氧化性能的影响

以磷酸、B₄C、SiC和Al₂O₃粉料为原料, 采用一种新颖的水热法对炭/炭(C/C)复合材料基体进行了抗氧化改性. 重点研究了水热反应温度对改性试样的物相组成、微观结构及抗氧化性能的影响. 采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、能量色散谱仪(EDS)及X射线光电子能谱(XPS)对改性后试样进行了表征. 结果表明：经过水热改性处理, 炭/炭复合材料表面缺陷被玻璃相B₂O₃、HPO₃和微晶Al(PO₃)₃所组成的涂层所覆盖, 材料的抗氧化性能明显提高; 抗氧化性能在120～200℃范围内随着水热改性温度的升高而提高; 在200℃水热改性后的炭/炭复合材料在700℃的空气中氧化10h后的质量损失仅为2.31%.

Influence of Temperature on Oxidation Resistance of Carbon/Carbon Composites Modified by a Hydrothermal Treatment

Carbon/carbon (C/C) composites are one of the most important high temperature structure materials; Which are oxidized remarkably above 400℃ in oxidative atmosphere. In order to improve the oxidation resistance of C/C composites, suspension mixtures prepared by mixing B₄C, SiC and Al₂O₃ powders and phosphoric acid solution were used as precursors to modify the C/C composites by a novel hydrothermal treatment. The influences of the hydrothermal treatment temperature on the phase, microstructure and anti oxidation property of the as-modified composites were investigated. The as modified C/C composites were characterized by X-ray diffraction, scanning electron microscope (SEM), energy dispersive spectroscope (PDS) and X-ray photoelectron spectroscopy (XPS) techniques. Results show that the surface of the C/C composites is covered by a coating composed of molten B₂O₃, HPO₃ and microcrystalline Al(PO₃)₃ after modified by the hydrothermal treatment, and their oxidation resistance is effectively improved in the temperature range from 120℃ to 200℃. The anti-oxidation property of the treated C/C composites is improved with increasing hydrothermal treatment temperature. The mass of the modified C/C composites losses only 2.31% after oxidized at 700℃ in air for 10h.