Synthesis of YSZ-coated SiC Particles and Their Sintering Behaviour

Abstract

Synthesis and sinterability of SiC-YSZ composite powders prepared by the homogeneous precipitation technique were studied. YSZ-coated SiC composite particles were obtained from the solutions consisting of [ZrO(NO₃)₂] = 0.092M, [Y(NO₃)₃] = 0.016M, [SiC] = 0.067-1.9M, [(NH₂)₂CO] = 3.6 - 7.2M, [H₂SO₄] = 0.18M. When H₂SO₄ concentration was higher or urea concentration was lower than these conditions, YSZ precipitate deposited separately from SiC particles. Mixture of SiC-YSZ composite powders and YSZ commercial powder containing 5-20mol%SiC was sintered at 1500-1650°C. They showed a higher sinterability than the mechanical mixture of SiC powder and YSZ powder. When SiC-YSZ composite powder (95mol%SiC) was used as the raw material, sintered bodies with 96 (SiC:20mol%) - 99% (SiC:5mol%) of theoretical density was obtained by sintering at 1550°C for 1h.