High‐Temperature Strength of Liquid‐Phase‐Sintered SiC with AlN and Re ₂ O ₃ (RE = Y, Yb)

Abstract

Using AlN and RE 2 O 3 (RE = Y, Yb) as sintering additives, two different SiC ceramics with high strength at 1500°C were fabricated by hot‐pressing and subsequent annealing under pressure. The ceramics had a self‐reinforced microstructure consisting of elongated α‐SiC grains and a grain‐boundary glassy phase. High‐temperature strength up to 1600°C was measured and compared with that of the SiC ceramics fabricated with AlN and Er 2 O 3 . SiC ceramics with AlN and Y 2 O 3 showed the best strength (∼630 MPa) at 1500°C, while SiC ceramics with AlN and Er 2 O 3 the best strength (∼550 MPa) at 1600°C.