摘要
碳化硅纤维因其具备卓越的高温抗氧化性、高强度、良好热稳定性在航空航天以及核领域展现出广阔的应用潜力.近年来,通过在先驱体中引入难熔金属异质元素以提升碳化硅纤维耐高温性能的研究备受关注.本研究采用液态聚碳硅烷(LPCS)与乙酰丙酮铪(Hf(AcAc)4)在常压高温条件下进行裂解重排,合成了含铪聚碳硅烷(PHCS)先驱体.随后,通过熔融纺丝、空气不熔化、高温裂解及高温烧结工艺,成功制备出含铪SiC陶瓷纤维.实验结果显示,Hf(AcAc)4在反应中充当交联助剂,形成的Si-O-Hf键提升了先驱体的交联程度,制备的PHCS陶瓷产率达77.42%,显著高于PCS(61.4%).通过空气不熔化方式实现纤维交联,在1200℃高温裂解过程中成功获得Si-C-O-Hf纤维,该纤维具有光滑的表面和无缺陷的结构,平均直径为15.8μm,平均抗拉强度1.85 GPa.对含铪碳化硅纤维的高温性能研究表明,其在1400和1600℃处理后强度保留率分别为81%和68%,表现出优异的耐高温性能,强度保留率高于Si-C-O纤维.1900℃高温热处理的Si-C-O-Hf纤维中的Hf以Hf-O键和Hf-C键的形式存在,SiC结晶程度更高,SiC晶粒尺寸增大,纤维直径变小,结构逐渐致密.本研究对于提升碳化硅陶瓷纤维的高温抗氧化性能具有一定的参考价值.
Silicon carbide fibers have demonstrated extensive application potential in the aerospace and nuclear fields due to their remarkable high-temperature oxidation resistance,high strength,and favorable thermal stability.In recent years,research focused on introducing refractory metal heteroelements into precursors to enhance the high-temperature resistance performance of silicon carbide fibers has attracted significant attention.In this study,liquid polycarbosilane(LPCS)and hafnium acetylacetonate(Hf(AcAc)4)were subjected to pyrolysis and rearrangement under normal pressure and elevated temperature conditions,leading to the synthesis of hafnium-containing polycarbosilane(PHCS)precursor.Subsequently,through the processes of melt spinning,air curing,pyrolysis,and high-temperature sintering,hafnium-containing SiC ceramic fibers were successfully fabricated.The experimental results indicate that Hf(AcAc)4 functions as a cross-linking assistant in the reaction.The formed Si―O―Hf bonds augment the cross-linking degree of the precursor,and the ceramic yield of the prepared PHCS reaches 77.42%,which is notably higher than that of PCS(61.4%).Fiber cross-linking was achieved via air curing,and Si―C―O―Hf fibers were successfully obtained during the pyrolysis process at 1200℃.These fibers possess a smooth surface and a defect-free structure,with an average diameter of 15.8μm and an average tensile strength of 1.85 GPa.Research on the high-temperature performance of hafnium-containing silicon carbide fibers reveals that after treatment at 1400 and 1600℃,the strength retention rates are 81%and 68%,respectively,exhibiting excellent high-temperature resistance performance and higher strength retention rates compared to Si―C―O fibers.In the Si―C―O―Hf fibers subjected to high-temperature heat treatment at 1900℃,Hf exists in the forms of Hf―O bonds and Hf―C bonds.The degree of SiC crystallization is enhanced,the grain size of SiC increases,the fiber diameter decreases,and the structure gradually becomes denser.This research holds certain reference value for improving the high-temperature oxidation resistance performance of silicon carbide ceramic fibers.
作者
陆俊冲
陈建军
张梦娜
李晓鸿
孙鑫
LU Jun-chong;CHEN Jian-jun;ZHANG Meng-na;LI Xiao-hong;SUN Xin(Institute of Advanced Ceramic Materials and Fibers,School of Materials Science and Engineering,Zhejiang Sci-Tech University,Hangzhou 310018,China)
出处
《高分子通报》
北大核心
2025年第7期1106-1116,共11页
Polymer Bulletin
基金
浙江省自然科学基金(基金号LZ23E020003)
国家自然科学基金(基金号51872262)。
关键词
碳化硅陶瓷纤维
聚铪碳硅烷
先驱体转化法
高温烧结
SiC ceramic fiber
Hafnium doped polycarbosilane
Precursor-derived conversion
High-temperature sintering
