Correlation between fracture toughness and microstructure of seeded silicon nitride ceramics
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Microstructure development and fracture toughness of Si3N4 composites were studied in the presence of seeds and Al2O3 + Y2O3 as sintering aids. The elongated β-Si3N4 seeds were introduced into two different α-Si3N4 matrix powders; one was the ultra fine powder matrix and the other was the coarse powder matrix. The amount of seeds varied from 0 to 6 wt%. The grain growth inhibition and the mechanism of toughening were discussed and correlated with microstructure. The maximum fracture toughness of 9.0 MPa m1/2 was obtained for ultra fine powder with 5 wt% seeds hot pressed at 1,700 °C for 6 h.
KeywordsAspect Ratio Fracture Toughness Y2O3 Silicon Nitride High Fracture Toughness
This work has been supported by the Ministry of Science and Environmental Protection of the Republic of Serbia and the Ministry of Economic Development and Trade of Ontario.
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