论文部分内容阅读
用相同牌号的T70 0炭布长纤维和炭毡短纤维交替叠层作为坯体 ,通过化学气相沉积(CVD)法生产二维C/C复合材料 ,尽管两种纤维具有很相近的结构和石墨化度 ,并经历相同的热处理过程 ,但同一C/C试样在随后的变温氧化和等温氧化过程中存在两个主要的氧化方向 ,一个是热解炭基体优先于炭布氧化 ,另一个是炭毡纤维优先于炭基体氧化。研究表明 ,两种纤维的物理性能 (如表面积、孔径分布和总孔体积 )有显著差别 ,即两种纤维的微孔结构和孔径分布有很大差别 ,从 3～ 1 0nm ,炭毡纤维的分布峰值比炭布纤维大得多 ,炭毡纤维的累积吸附孔体积的增长也比炭布纤维快 ,而且炭毡纤维的最大孔径比炭布纤维的大得多。正是这些因素使得炭布纤维比炭毡纤维具有更强的抗氧化性 ,导致了其抗氧化和氧化活性的明显不同。因此 ,即使炭布纤维和炭毡纤维具有相同的结构 ,并经过同样的热处理过程 ,在被用作坯体生产C/C复合材料前 ,应仔细考虑其物理性能。
Two-dimensional C / C composites were produced by chemical vapor deposition (CVD) using alternating stacks of the same grades of T70 0 carbon cloth and carbon felt short fibers, although the two fibers have very similar structures and graphite Degree, and go through the same heat treatment process. However, there are two main oxidation directions in the same C / C sample during the subsequent temperature-programmed oxidation and isothermal oxidation. One is that the pyrolytic carbon matrix is preferentially oxidized and the other is Carbonfiber preferentially oxidizes the carbon matrix. The results show that there are significant differences in the physical properties (such as surface area, pore size distribution and total pore volume) of the two fibers, that is, the pore structure and pore size distribution of the two fibers are quite different. From 3 to 10 nm, The peak of the distribution is much larger than that of the carbon cloth fiber, and the cumulative pore volume of the carbon fiber also grows faster than that of the carbon cloth fiber, and the maximum pore diameter of the carbon felt fiber is much larger than that of the carbon cloth fiber. It is these factors that make the carbon fiber more strongly oxidized than the carbon fiber, resulting in significant differences in its antioxidant and oxidizing activities. Therefore, even if the carbon fiber and the carbon fiber have the same structure and are subjected to the same heat treatment process, their physical properties should be carefully considered before being used as a green body for the production of C / C composites.