Volume 16, Issue 2, 2007

FABRICATION AND PROPERTIES OF ALUMINUM-CONTAINING SILICON CARBIDE FIBRES

Yuxi Yu^1,2

¹ Advanced Materials Laboratory, Department of Materials Science and Engineering, Xiamen University, Xiamen, Fujian 361005, P. R. China
² Key Lab of C. F. C, Institute of Aerospace and Materials Engineering, National University of Defense Technology, Changsha, Hunan 410073, P. R. China E-mail address: yu_heart@163.com

Received 10 January 2007; accepted 7 February 2007

ABSTRACT

By introducing hetero-element aluminum into ceramic precursor and then sintering, polycrystalline, stoichiometric SiC fibres can be prepared. Two types of aluminum-containing SiC fibres were fabricated by the use of aluminum-containing polycarbosilane (Al-PCS). The air-cured Al-PCS fibres were pyrolyzed in inert gas up to 1350^oC to obtain SiC(OAl) fibres, which were converted into SiC(Al) fibres by heating in argon up to 1800 oC. The properties and performances of SiC(OAl) and SiC(Al) fibres were studied by chemical element analysis, scanning electron microscopy (SEM), X-ray diffraction (XRD), tensile strength test, heat resistance and creep resistance. These results show SiC(Al) are polycrystalline SiC fibres, have a near stoichiometric composition. The tensile strength, Young’s modulus and diameter of the SiC(OAl) fibres are 2.6 GPa, 210 GPa, 12 µm, respectively. The tensile strength, Young’s modulus and diameter of the SiC(Al) fibres are 2.1 GPa, 405 GPa, 10 µm, respectively. The SiC(Al) fibres have higher thermal stability, and better creep resistance than the SiC(OAl), the Nicalon and the Hi-Nicalon fibres.