中文摘要：

用SiO2和α-SiaN4在氮气中通过碳热还原-常压反应烧结法，原位反应制备了氮化硅多孔陶瓷。由于反应中存在大量的质量损失，烧结的制品为高气孔的材料。通过改变原料中α—Si3N4与SiO2和C粉的相对含量，可以形成具有细小针状结构的争Si3N4晶粒，以此获得气孔率可控的高性能的多孔氮化硅材料。随着原料中α-Si3N4含量的增大，烧结后，样品的总质量损失逐渐减小，收缩率逐渐降低，气孔率逐渐减小，弯曲强度逐渐增大。当α-Si3N4的质量分数为50％时，碳热还原-常压反应烧结的样品中的β—Si3N4晶粒具有更高的长径比，样品气孔率为68．7％，具有优良的力学性能，弯曲强度达到37．7MPa。

英文摘要：

Porous silicon nitride ceramics were prepared directly by carbothermal reduction-pressureless reaction sintering in nitrogen using SiO2 and α-Si3N4 as raw materials. The high porosity of the materials occurs because there is a great mass loss in the reaction. The material has finer and needle-like α-Si3N4 grains when the relative content of α-Si3N4, SiO2 and C is changed. So high-performance and porosity-controlled porous silicon nitride could be obtained. With an increase in the α-Si3N4 content, its mass loss, linear shrinkage, and porosity decrease, and its flexural strength increases accordingly. The sample with the addition of 50% （in mass） α-Si3N4 has a higher aspect ratio of α-Si3N4 grains, a porosity of 68.7% and better mechanical properties, its flexural strength reaching to 37.7 MPa.