Si_3N_4/AlN对Sialon/刚玉复合材料组织和性能的影响

Effect of Si_3N_4/AlN Additives on Microstructure and Properties of Sialon Bonded Corundum Refractories Synthesized Once Through

以棕刚玉,Al,Si,Al2O3为原料,利用一步工艺合成了Sialon/刚玉复合材料·研究了Si3N4/AlN复合添加剂对复合材料组织、性能以及复合材料中N含量的影响·研究结果表明:材料中N含量随着Si3N4/AlN复合添加剂的增加而增加,材料的强度随着Si3N4/AlN复合添加剂的增加呈现出先升高后降低的变化趋势;当氮化温度超过1330℃,氮化时间超过8h后,添加Si3N4/AlN的材料中N含量基本上达到饱和值,添加Si3N4/AlN可以降低Sialon相的合成温度;1230～1280℃是一个重要的前期氮化温度,添加Si3N4/AlN的材料在该温度可完成整个氮化反应的94 2%,早期对Al,Si的充分氮化有利于Sialon相的生成和晶形完整发育·

Sialon-Corundum multiphase refractories were synthesized once through using silicon powder, aluminum powder and black corundum as raw materials. Effects of Si_3N_4/AlN additives on N content, modulus of rupture and microstructure of Sialon were investigated. The results showed that the N content in the synthesized material increase and its flexural strength increases then decreases along with the increasing Si_3N_4/AlN content. N content in the specimen approaches to saturation after nitriding at 1330℃ for over 8 hours. The additive may lower greatly the synthesizing temperature of the Sialon phase. In the synthesis process the range from 1230℃ to 1280℃ is an important initial nitriding phase in which the whole nitriding reaction can be completed by 94.2%. It was proved that nitriding fully Al and Si in early stage is beneficial to the formation and complete grain growth of Sialon phase.