摘要
The yttrium as a sintering aid was introduced into polycarbosilane（PCS） to prepare yttrium-containing PCS（PYCS）.Two types of yttrium-containing SiC fibres,the SiC（OY） fibres and the SiC（Y） fibres,were fabricated with PYCS.The structural evolution and the associated properties on changing from SiC（OY） to SiC（Y） fibres during the sintering process were studied.The chemical composition of the SiC（OY） fibres is SiC1.53O0.22Y0.005 with an amorphous structure.The composition of SiC（Y） fibres is SiC1.23O0.05Y0.005.The fibres are composed of a large number of β-SiC crystallites with a size of 50 nm and a small amount of α-SiC crystalline.The tensile strength and fracture toughness of the SiC（OY） fibres are 2.25 GPa and 2.37 MPa·m1/2,respectively,and 1.61 GPa,1.91 MPa·m1/2,respectively for SiC（Y） fibres.The SiC（Y） fibres have a higher thermal stability than the SiC（OY） fibres.
将钇元素作为烧结助剂引入到聚碳硅烷(PCS)中制备含钇PCS。由含钇PCS制成SiC(OY)和SiC(Y)2种碳化硅纤维。对SiC(OY)纤维转变成SiC(Y)纤维的结构与相关特性的变化进行研究。SiC(OY)纤维的化学组成为SiC1.23O0.05Y0.005,纤维是无定型结构;SiC(Y)纤维含有大量的直径为50nm的β-SiC晶粒和少量的α-SiC晶粒,钇元素存在于SiC晶粒之间。SiC(OY)的拉伸强度为2.25GPa,断裂韧性为2.37MPa.m1/2;SiC(Y)的拉伸强度为1.61GPa,断裂韧性为1.91MPa.m1/2;SiC(Y)纤维比SiC(OY)纤维具有更好的热稳定性。
基金
Projects (51175444,50532010) supported by the National Natural Science Foundation of China
Project (2011121002) supported by the Fundamental Research Funds for the Central Universities, China
Project (2009J1009) supported by Scientific and Technological Innovation Platform of Fujian Province,China
