壳聚糖凝胶注模成型Al2O3陶瓷的致密化及力学性能研究

Study on the Densification and Mechanical Properties of Al2O3 Ceramics Prepared by Gelcasting Method with Chitosan

以α-Al2O3粉为原料,BaO＋Ti O2为烧结助剂,壳聚糖为有机单体,戊二醛为交联剂,采用凝胶注模法制备了Al2O3陶瓷坯体,利用无压烧结工艺实现了Al2O3陶瓷的致密化。研究了壳聚糖含量及固相含量对Al2O3陶瓷的显微结构及力学性能的影响规律以及壳聚糖的固化机理。试验结果表明,壳聚糖通过发生聚合反应,形成网络结构,使Al2O3粉原位固化。BaO＋TiO2烧结助剂通过实现液相烧结及固溶机制,促进材料致密化。随着壳聚糖含量及固相含量增加,Al2O3陶瓷的致密度及抗弯强度均呈先增加后降低趋势。

Green body of Al2O3 ceramic were prepared by the gel casting method with Al2O3 as starting powder, BaO＋TiO2 as sintering additives, chitosan as the organic monomer and gtutaraldehyde as initiator. Pressure-less sintering method was applied to realize the densification of Al2O3 ceramic. The effects of the chitosan content and solid content on the microstructure and mechanical properties of Al2O3 ceramic were investigated and the solidification mechanism of chitosan was also studied. The experimental results show that, the polymerization reactions happen in the chitosan and net structures forms, then the raw Al2O3 powders solidify. The BaO＋TiO2 sintering additive promote the densification of Al2O3 ceramic through liquid sintering and solid solution mechanism. With increasing of chitosan content and solid content, both the relative density and flexure strength of Al2O3 ceramic firstly increase and then decrease.