温度对溶剂热改性C/C复合材料显微结构和氧化性能的影响

以硼酸三正丁酯、乙酸、B2O3粉体为原料,无水乙醇为溶剂,采用一种新颖的溶胶/凝胶结合溶剂热法对C/C复合材料基体进行了抗氧化改性.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.重点研究了溶剂热反应温度对改性后试样的物相组成、微观结构和氧化性能的影响.结果表明:经过溶剂热改性处理后,C/C复合材料表面缺陷被玻璃相B2O3组成的涂层所覆盖,材料内部一部分孔隙也被B2O3相填充,且随着溶剂热温度的上升,试样表面的微裂纹逐渐消失,B2O3涂层的致密度上升；C/C基体的抗氧化性能随着溶剂热改性温度(范围353～433 K)的升高而提高；经433 K溶剂热改性后的C/C复合材料在873 K的空气中氧化16 h后的质量损失仅为4.09％.

Influences of Temperature on Microstructure and Oxidation Resistance of Carbon/Carbon Composites Modified by Solvothermal Process

In order to improve the oxidation resistance property of C/C composites,the C/C composites were modified by a novel sol-gel/solvothermal process.The suspension mixtures were prepared by mixing tributyl borate sol,ethanol,acetic acid and B2O3 powder.The as-modified C/C composites were characterized by X-ray diffraction(XRD),scanning electron microscope(SEM),energy dispersive spectroscope(EDS) and X-ray photoelectron spectroscopy(XPS) techniques.The influences of the solvothermal temperature on the phase,microstructure and anti-oxidation property of the as-modified composites were investigated.Results show that the surface of the C/C composites are covered by a coating consisted of molten B2O3 and the internal microholes are occupied by B2O3.With the increase of solvothermal temperature,and the density of the coatings also increases.The anti-oxidation property of the modified C/C matrix is effectively improved with the increase of solvothermal treatment temperatures from 353 K to 433 K.The mass loss of the modified C/C composites is only 4.09% after oxidation at 873 K in air for 16 h.