铝粉对刚玉-氮化硅复合材料微观结构和性能的影响(英文)

Effect of Aluminium Powder on Microstructure and Property of Corundum-Silicon Nitride Composites

借鉴"过渡塑性相工艺"思想,在刚玉-氮化硅复合材料中引入12.5%(质量分数)的铝粉,研究了铝粉对刚玉-氮化硅复合材料成型性能以及1 600℃空气中烧成后样品的体积密度、显气孔率和耐压强度的影响;利用X射线衍射仪和扫描电镜对材料的物相和微观结构进行了分析。结果表明:在刚玉-氮化硅复合材料中引入铝粉,有利于成型过程中孔隙的填充,坯体显气孔率由21.57%下降为20.42%,坯体致密度提高。样品在空气气氛中烧成后,未加铝粉样品表面形成的致密氧化膜厚度约为3 mm,而加入铝粉样品表面氧化膜的厚度约为0.2 mm;铝粉先于氮化硅粉发生原位氧化,降低了样品内部的氧分压,残留的铝粉发生氧化或氮化反应生成活性中间产物,促进了样品的烧结。

Corundum-silicon nitride samples were sintered at 1 600 ℃ in air by introduction of 12.5%（in mass） aluminium powder inspired by a transient plastic phase process.Effects of aluminium powder on the forming property as well as bulk density,apparent porosity,and compressive strength of the samples were investigated.The phase composition and microstructure of the reaction prod-ucts were analysed by X-ray diffractometer and scanning electron microscope.The results indicate that the plasticity of aluminium favors the filling of the interstices during the forming process and improves the densification of the corundum-silicon nitride materi-als.The apparent porosity decreases from 21.75% to 20.42%.The samples without introduction of any aluminum powder have a compact superficial oxidized film of 3 mm,and the samples with the introduction of aluminum powder have the film of 0.2 mm after fired in air atmosphere.Aluminium precedes silicon nitride to be oxidized in situ,reducing the oxygen partial pressure inside the sample.The residual aluminium is oxidized or nitrided to form the active intermediate products,contributing to the sinter of the materials.