The effect of nano-Si_{3N_{4 on properties of silicon nitride ceramics

Silicon nitride ceramics were fabricated using submicron Si3N4 powder and nano-Si3N4, adding Al2O3 and Y2O3 by isostatic pressing and SSN. In the paper, the dispersion of nano-Si3N4 powder, the effect of different nano-Si3N4 concentrations on Si3N4 ceramic mechanical properties, application performances and nano-Si3N4 dispersion are discussed. The results demonstrated that the dispersion effect of ethanol was better than water as solvent when PEG was the dispersant agent and the time was 40 min by a supersonic instrument. Flexural strength, hardness and fracture toughness of the specimens were the highest when the content of nano-Si3N4 was 3% by weight.