Fabrication of β-Si3N4 with high thermal conductivity under ultra-high pressure

In this work, the Silicon nitride composite ceramics (β-Si 3 N 4 ) by ultra-high pressure sintering were investigated. And the effect of sintering temperature , hold time and α-Si 3 N 4 powders on the sintering process had been analyzed in detail. These experimental results showed the larger particle size and lower porosity had an obvious effect on the thermal conductivity . Meanwhile, the addition of α-Si 3 N 4 powder could be also attributed to thermal conductivity. We had been calculated the porosity of β-Si 3 N 4 composite ceramics that the sample D (0.26%) was lower than the others samples. For a comparison, the thermal conductivity of sample D was up to 64.6 W/m K that was also attributed to its higher diffusion rate and small grain size.