冲击波合成立方氮化硅粉体的耐腐蚀性及热稳定性

THERMAL STABILITY AND CORROSION RESISTANCE OF CUBIC SILICON NITRIDE POWDERS PREPARED BY SHOCK SYNTHESIS

以α-Si3N4为原料,采用冲击波法合成了γ-Si3N4粉体。在1660～1690K温度下对γ-Si3N4粉体进行高温稳定性研究并利用氢氟酸对γ-Si3N4粉体进行耐腐蚀性研究。结果表明:真空条件下,在1660K时,γ-Si3N4粉体较为稳定;在1680K时,保温10min和30min后,γ-Si3N4向β-Si3N4的转变率分别为5%和90%。在1690K时,γ-Si3N4在10min内能够完全转变为β-Si3N4。在470K的温度下γ-Si3N4粉体能够与氢氟酸缓慢反应。在490K的温度下,0.2gγ-Si3N4粉体腐蚀5h后,能够与氢氟酸完全反应,生成气体而挥发。

The thermal stability of γ-Si3N4 powder prepared by shock wave synthesis using α-Si3N4 as raw material was investigated at temperatures between 1 660 K and 1 690 K,and its corrosion resistance to hydrofluoric acid was studied as well.The results show that γ-Si3N4 powder is quite stable at 1 660 K,and after the powder is soaked at 1 680 K for 10 and 30 min,the ratio of transformation from γ-Si3N4 to β-Si3N4 is about 5% and 90%,respectively.The γ-Si3N4 powder can be completely transformed into β-Si3N4 after being soaked at 1 690 K for 10 min.The γ-Si3N4 powder can react with hydrofluoric acid at 470 K.At 490 K,0.2 g γ-Si3N4 powder can completely react with hydrofluoric acid and be converted into gas phase after 5 h.