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不同分子量聚碳硅烷的性能及对C/ C-SiC 复合材料增密的影响
黄 剑,李 辉,嵇阿琳,王玲玲,刘 博
西安航天复合材料研究所,西安 710025
摘要:
<div>以四种分子量级别聚碳硅烷(PCS)为浸渍剂&#41900;采用CVD 和浸渍-裂解工艺制备了C/ C-SiC 复合</div><div>材料&#41900;分析了四种分子量级别PCS 的分子量、软化点&#41900;分子结构和热失重性能&#41900;采用压汞法测试试件的孔隙分</div><div>布特性&#41902; 分析表明&#41900;PCS 的软化点和800℃转化率都随着分子量的提高而提高&#41915;四种分子量级别的PCS 热分解</div><div>过程基本相同&#41900;分子的支化程度差异不大&#41902; 数均分子量为1 178、1 333 的PCS 的整体致密化效率要高于数均</div><div>分子量为1 550 的PCS&#41900;经过7 个周期致密后&#41900;分子量为1 178 的PCS 所致密试样的累积孔隙容积最高&#41900;分子量</div><div>为1 550 的PCS 所致密的试样最低&#41902; 前5 个浸渍裂解致密周期采用分子量为1 550 的PCS&#41900;以后周期采用分子</div><div>量为1 178 或1 333 的PCS&#41900;可以达到较高的致密效率。</div>
关键词:  聚碳硅烷,分子量,C/ C-SiC 复合材料,密度
DOI:
分类号:TB33
基金项目:
Performance of Polycarbosilane With Different Molecular Weigh andIts Effect on Densification of C/ C-SiC Composites
Abstract:
<div>C/ C-SiC composites were prepared by CVD &#41900;impregnation and pyrolysis method using polycarbosilane</div><div>(PCS) with four number average molecular weight as impregnant.The molecular weight&#41900; softening point&#41900; molecular struc ̄</div><div>ture and thermogravimetic performance of PCS were determined&#41900; and the distribution of pores were analyzed by means of</div><div>mercury intrusion method .The results showed that the softening point and rate of conversion at 800℃ of PCS increased with</div><div>increasing molecular weight of PCS. The pyrolysis process of PCS with four molecular weight grade were identical&#41900; and</div><div>branch degree did not have significant difference. The integral densification efficiency of PCS with molecular weight 1 178</div><div>and 1 333 was higher than that of PCS with molecular weight 1 550. The cumulative pore content of sample densified by PCS</div><div>with molecular weight 1 178 was maximum after seven densification cycles&#41900; and that of sample densified by PCS with molec ̄</div><div>ular weight 1 550 was minimum.When PCS with molecular weight 1 178 and 1 333 was used in previous five ̄cycles and mo ̄</div><div>lecular weight 1 550 was used in other cycles&#41900; the material could be densified more efficiently.</div>
Key words:  PCS&#41900  Molecular weight&#41900  C/ C-SiC composites&#41900  Density