FABRICATION OF SiC FIBRE-REINFORCED SiC MATRIX COMPOSITES BY LOW TEMPERATURE MELT INFILTRATION METHOD USING Si-Hf AND Si-Y ALLOY

• Published in: Ceramic Engineering and Science Proceedings pp. 101 - 111
• Main Authors: Okubo, Y, Yano, T, Yoshida, K, Aoki, T, Ogasawara, T
• Format: Journal Article
• Language: English
• Published: 01.01.2015
• Subjects: Ceramics; Fiber composites; Hafnium; Infiltration; Melts; Modulus of rupture in bending; Silicon; Silicon carbide; Yttrium
• ISBN: 1119031184; 9781119031185
• ISSN: 0196-6219

SiC fibre preforms were coated with carbon and SiC by CVI and used in the preparation of SiC fibre-reinforced SiC composites by melt infiltration of silicon or silicon alloys containing 8.5 at% hafnium or 18 at% yttrium. The alloys were used in preference to silicon to lower the infiltration temperature. The composite prepared using the Si-Hf alloy consisted of SiC, Si and HfSi2, whilst that prepared using the Si-Y alloy consisted of SiC, Si and Y3Si5. The flexural strength of the composite prepared using the Si-Hf alloy processed at 1350 C was higher than that of the composite prepared using silicon and processed at 1450 C. The maximum strength of the composite prepared using the Si-Y alloy and processed at 1290 C was higher than that of the composite prepared using the Si-Hf alloy processed at 1375 C. This is attributed to a reduction in SiC fibre degradation by processing at a lower temperature.