Si_3N_4-SiC纳米复合陶瓷材料的研究

Si_3N_4-SiC ceramic nanocomposites

用粒度为 ５０～７０ ｎｍ的纳米级 ＳｉＣ粉体与微米级的 Ｓｉ３Ｎ４粉体复合来制备 Ｓｉ３Ｎ４－ＳｉＣ纳米复合陶瓷材料，对纳米ＳｉＣ含量不同的Ｓｉ３Ｎ４－ＳｉＣ纳米复合陶瓷材料的微观组织结构与性能的关系进行了研究。结果表明：纳米ＳｉＣ质量分数为１０％时，经热压烧结法制备的Ｓｉ３Ｎ４－ＳｉＣ纳米复合陶瓷材料的抗弯强度为 ８４４ ＭＰａ，断裂韧性为 ９． ７ ＭＰａ· ｍ１／２。微观组织结构的研究还表明，纳米ＳｉＣ的不同含量影响着基体Ｓｉ３Ｎ４的晶粒形貌，从而决定了复合材料的性能。探讨了纳米级ＳｉＣ在基体中的形态、分布及其对基体强化增韧的新机制。

Si3N4-SiC nanocomposites have been fabricated using SiC powder of 50 - 70 nm particle size and Si3N4 powder of 2-3 μm particle size by hot press sintering. In the paper, the relations between the microstructure and performance are studied for Si3N4-SiC nanocomposites with different SiC contents. The results showed that Si3N4-SiC nanocomposites with 10% SiC exhibited a high fracture toughness and flexural strength. They are respectively 9. 7 MPa·m1/2 and 844MPa. The distribution and morphology of SiC in the Si3N4 matrix and the toughening mechanism of Si3N4-SiC nanocomposites are discussed.