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Preparation of tough á-SiAlON ceramics by spark plasma sintering with â-Si3N4 as raw materials

Guanghua Liu, Kexin Chen, Jiangtao Li

In-situ toughened Yb á-SiAlON ceramics were prepared by spark plasma sintering with â-Si3N4 as raw materials. Dense á-SiAlON sample with rod-like grains was prepared by sintering at 1600oC for 10 min, which showed a fracture toughness of 7.7 MPa·m1/2. XRD analysis revealed a strong preferred orientation of rod-like grains in the á-SiAlON sample. It was proposed that, the higher toughness was caused by the reinforcing effect of rod-like grains, and the formation of rod-like crystals was favored by using â-Si3N4 as raw materials and applying a fast heating rate during sintering.