粘土碳热还原氮化二步法制备β-Sialon结合刚玉复相材料

Preparation of β-Sialon bonded corundum composite from clay by carbothermal reduction nitridation and two method

以天然粘土为原料 ,采用碳热还原氮化法合成了β Sialon粉体 ,再将它与刚玉复合 ,常压下烧结制备了β Sialon结合刚玉复相材料 ;研究了合成β Sialon粉体的反应过程和最佳工艺参数 ,在反应温度为 1 5 0 0℃ ,保温 6h ,碳的质量分数为2 0 % ,氮气流量为 1 .5L·min- 1 的工艺条件下 ,产物中的β Sialon可达 90 % (质量分数 )以上。测定了添加不同烧结助剂的 β Sialon结合刚玉复相材料的力学性能 ,并用SEM观察了其断口形貌 ,发现添加稀土氧化物La2 O3和Y2 O3的样品烧结相当致密 ,抗折强度分别为 1 72MPa和 2 0 1MPa。

Sialon powders were firstly synthesized using natural clay as starting material by carbothermal reduction nitridation method,then they were compounded with corundum by sintering to prepare β Sialon bonded corundum composites.The reaction process of synthesizing β Sialon powder was researched and the optimum synthesizing process parameters are:reaction temperature 1500 ℃,holding time 6 h,mass percent of C 20%,N 2 flow 1.5 L·min -1 .Under such conditions,the content of β Sialon in the products is over 90%.The mechanical property and the fracture microstructures of the β Sialon bonded corundum composites with different sintering agents were studied.It is found that the composites with La 2O 3 and Y 2O 3 added are very dense and their moduli of rupture are 173 MPa and 201 MPa respectively.