Liquid phase sintering of SiC was performed using rare-earth oxide R 2O3 (R = Y, Yb, and Sm) and AlN sintering additives. The addition of 2 vol% β-SiC seeds or α-SiC platelets resulted in bimodal microstructure after annealing for 10 hours at 1850°C in mixed N 2 + Ar atmosphere. Samples had a negligible weight loss after hot pressing. The bimodal microstructure contributed to the improvement of fracture toughness. Seeding by α-SiC seeds stimulated the β → α-SiC phase transformation and increased the hardness. Samples with α-SiC seeds and complex Yb2O3 + Sm2O3 + AlN additives had a Vickers hardness of 27.5 GPa. Seeding by β-SiC whiskers hindered the β → α-SiC phase transformation and increased the fracture toughness up to 6.5 MPa.m1/2.
|Number of pages||12|
|Publication status||Published - 2003 Jan 1|
|Event||Silicon-Based Structural Ceramics for the New Millenium Symposium, Proceedings - St. Louis, MO, United States|
Duration: 2002 Apr 28 → 2002 May 1
All Science Journal Classification (ASJC) codes
- Ceramics and Composites
- Materials Chemistry