由聚钛碳硅烷制备高结晶近化学计量比SiC(Ti)纤维  

Preparation of Nearly Stoichiometric SiC(Ti)Fibers with Highly Crystalline Microstructure from Polytitanocarbosilane

作　　者：苟燕子[1] 康伟峰 张庆雨 GOU Yanzi;KANG Weifeng;ZHANG Qingyu(Science and Technology on Advanced Ceramic Fibers and Composites Laboratory,College of Aerospace Science and Engineering,National University of Defense Technology,Changsha 410073,China)

机构地区：[1]国防科技大学空天科学学院,新型陶瓷纤维及其复合材料重点实验室,长沙410073

出　　处：《无机材料学报》2024年第12期1377-1383,共7页Journal of Inorganic Materials

基　　金：国家自然科学基金(52272100);湖南省自然科学基金(2022JJ30662);新型陶瓷纤维及其复合材料重点实验室基金(WDZC20215250507)。

摘　　要：SiC纤维具有高强度、耐高温、抗氧化等优良性能,可应用于航空航天及高技术装备等重要领域。然而,当前国产含钛SiC纤维的制备温度较低,纤维中仍富含多余的杂质氧和游离碳,这严重影响了其耐高温性能。本工作以低软化点聚碳硅烷(LPCS)和钛酸四丁酯(Ti(OBu)_(4))为原料合成了聚钛碳硅烷(PTCS)先驱体,所得PTCS的钛质量分数为0.36%~1.81%。然后经过PTCS熔融纺丝、空气不熔化、热解无机化和高温烧结,制备了高结晶近化学计量比的SiC(Ti)纤维,该纤维的C、O元素的质量分数分别为30.45%和<1.0%,C/Si比约为1.05,β-SiC晶粒尺寸为100~200 nm。纤维中的Ti元素主要以TiC相的形式存在,从而有助于纤维的高温烧结致密化。SiC(Ti)纤维表面光滑致密,纤维芯部呈现明显的穿晶断裂特征,平均单丝拉伸强度为2.04GPa,杨氏模量为308GPa。本研究为研制高性能连续SiC纤维提供了重要的参考价值。Due to high tensile strength,excellent high-temperature and oxidation resistance,SiC fibers could be applied in many important fields such as aerospace and high-tech equipment.However,the current preparation temperature of domestically produced titanium-containing SiC fibers is relatively low,while the fibers are still full of excess oxygen and free carbon,which seriously affects their high-temperature resistance.In this work,the polytitanocarbosilane(PTCS)precursor was synthesized by using low-softening-point polycarbosilane(LPCS)and tetrabutyl titanate(Ti(OBu)_(4)).Mass fraction of titaniumin in the precursor was in the range of 0.36%–1.81%.The nearly stoichiometric polycrystalline SiC(Ti)fibers were successfully prepared through PTCS melt spinning,air curing,pyrolysis,and high-temperature sintering.Mass fractions of carbon and oxygen in SiC(Ti)fibers were 30.45%and<1.0%,respectively,with a C/Si ratio of approximately 1.05 andβ-SiC grain size of 100–200 nm.The titanium element in SiC(Ti)fibers mainly existed in the form of TiC phase,which was beneficial to densification of the fibers during the sintering process.The SiC(Ti)fibers showed smooth and dense surface,exhibiting obvious transgranular fracture.Average tensile strength of the SiC(Ti)fibers was 2.04 GPa,and elastic modulus was 308 GPa.All results of this work provide important reference for the development of high-performance continuous SiC fibers.

关 键 词：聚钛碳硅烷 熔融纺丝 SIC纤维 先驱体陶瓷 高温烧结 

分 类 号：TQ343[化学工程—化纤工业]