Fe 掺杂和热处理对 SiC 纤维微结构与电性能影响规律的研究

摘要

利用氧化交联技术制备了含铁量分别为0,1％,2％(质量分数)的3种碳化硅纤维,并将其置于氩气环境进行了不同温度、不同时间的热处理.研究了Fe 掺杂及热处理对于 SiC 纤维微观结构及电阻特性的影响规律.结果表明,在 Fe 掺杂和热处理的协同作用下,该碳化硅纤维电阻率可由13847Ω•cm 连续降低至6Ω•cm.利用统计理论“相关分析”算法研究纤维微观结构与电阻率关系的结果表明,在实验条件下,β-SiC 的晶粒尺寸对纤维电阻率的影响最为显著.根据实验结果,提出了该含铁 SiC 纤维微结构演化的模型.%Silicon carbide fibers doped with iron of 0-2wt% were prepared from iron-containing polycarbosilane by using oxygen-curing method.The as-prepared fibers were heated in high purity argon from 700 to 1 100 ℃up to 100 h.With the change of treating parameters,the specific resistivity of the fibers decreased from 13 847 to 6 Ω•cm while the content and crystallinity of the multi-phases in fibers varied non-monotonically.Linear re-lationship between microstructure with electrical property was evaluated using pearson coefficients.Among the tested factors,grain size ofβ-SiC was the most relevant to specific resistivity,effect of iron content was subor-dinate.Mechanism on microstructure evolution of the iron-doped fiber was proposed.