C/C复合材料开孔孔隙度和比表面积对其氧化性能的影响

来源期刊：中南大学学报(自然科学版)2002年第5期

论文作者：廖寄乔 黄伯云 石刚 陈腾飞 熊翔

文章页码：500 - 504

关键词：C/C复合材料;开孔孔隙度;比表面积;氧化性能

Key words：carbon/carbon composites; open porosity; specific surface area; oxidation property

摘    要：选用光学显微结构为光滑层沉积热解炭、试样的石墨化度近似相等(约为37%)的A,B,C,D,E 5个不同开孔孔隙度和比表面积的C/C复合材料试样(孔隙度和比表面积分别为P_A=14.03%,S_A=1.463 m²/g ; P_B=18.01% ,S_B=2.701 m²/g ;P_C=24.65% ,S_C=3.594 m²/g ;P_D=12.07%,S_D=6.527 m²/g;P_E=15.79%,S_E=6.722 m²/g)在氧气流中进行变温氧化实验;具有不同比表面积和孔隙度的试样F,G,H(P_F=15.66%,S_F=6.026 m²/g;P_G=18.32%,S_G=3.573 m²/g;P_H=12.16%,S_H=2.262 m²/g)在氧气流中进行等温氧化实验;具有不同比表面积和相 同孔隙度的试样I,J(P_I=13.61%,S_I=0.853 5 m²/g;P_J=13.60%,S_J=0.429 3 m²/g)在马弗炉中进行静态空气氧化实验.结果表明:试样的比表面积控制了氧化进度,而与材料孔隙度无直接关系;氧化优先发生在纤维/基体和基体/基体界面,随后沿着界面间裂纹进行.

Abstract: The oxidation tests of A~E five with different porosity and specific surface area C/C composites(P_A=14.03%,S_A=1.463 m²/g;P_B=18.01%,S_B=2.701 m²/g;P_C=24.65%,S_C=3.594 m²/g;P_D=12.07%,S_D=6.527 m²/g;P_E=15.79%,S_E=6.722 m²/g) for non-isothermal oxidation and three different porosity and specific surface area C/C composites samples F,G and H(P_F=15.66%,S_F=6.026 m²/g;P_G=18.32%,S_G=3.573 m²/g;P_H=12.16%,S_H=2.262 m²/g) for is othermal oxidation in O₂ and two samples I and J (P_I=13.61%,S_I=0.853 5 m²/g;P_J=13.60%,S_J=0.4293 m²/g) which had approximate porosity and different specific surface area values for static air oxidation were studied, and all the samples selected in this investigation had the optical smooth laminar structure and approximately same graphitization degree. The results show that the oxidation is controlled by the specific surface area rather than by the open porosity or the densification degree of samples or the amount of pore entrance. The oxidation oc- curs preferentially at the fiber/matrix interface and pyrocarbon/pyrocarbon interface, and then progresses along the microcracks between the interfaces.