令不同氧含量的聚碳硅烷氧化交联丝在高纯氨气中氮化热解、脱碳氨化,继而在高纯氮气下高温热引发缩合/转氨基反应,生成硅氧氮烷并最终形成氧含量不同的硅氧氮(SI—O—n)陶瓷纤维。Xrd、EPMA和TEM研究结果显示,所有元素在硅氮氧纤维中均匀分布,随着交联丝O含量增加,SI—O—n陶瓷纤维的O含量随之增加,力学性能下降,而陶瓷产率则先升后降。高氧时纤维陶瓷产率下降是因为在高温热解时发生了相分解。Xrd和TEM结果表明,氧含量不同的陶瓷纤维经1 500℃高温处理后,均仍为无定型。氧可能对氮化硅的结晶有抑制作用。In this work,PCS fibers,cured with different oxygen contents,were conducted by pyrolysis nitridation for carbon removal and amination in the ammonia atmosphere,and then through condensation/nitridation reaction at high temperature in the nitrogen atmosphere to produce silicon oxynitride fibers.Results of XRD, EPMA and TEM showed that,all of the elements in the ceramic fibers dispersed uniformly,and as the oxygen content in the cured fibers increased,it also increased in the ceramic fibers but with a drop in mechanical properties.However,the ceramic yield rose first and then fell because of the phase decomposition at high temperature.Indicated by the results of XRD and TEM,even after heat treatment at 1 500℃,ceramic fibers were still amorphous regardless of how much the oxygen content was.The oxygen maybe play a role like impurity in the fibers,which inhibites the crystallization of silicon nitride.国家自然科学基金面上资助项目(51002127;51072169
