SEMINAR 
The State Key Lab of 
High Performance Ceramics and Superfine Microstructure 
Shanghai Institute of Ceramics, Chinese Academy of Sciences
 中国科学院上海硅酸盐研究所高性能陶瓷和超微结构国家重点实验室 

　　Laser-based Processing of Transparent Microspheres in the Systems Al₂O₃-Y₂O₃-ZrO₂ (AYZ) and K_0.5Na_0.5NbO₃ (KNN)

　　Speaker

　　Jürgen G. Heinrich

　　Institute of Nonmetallic Materials

　　Department for Engineering Ceramics

　　时间：11月20日 （星期三）上午9:00

　　地点：2号楼607会议室

　　联系人：江东亮 院 士

　　         曾宇平 研究员

　　Abstract:

　　The development of transparent ceramics has been an interesting research area in the last years. The conventional way to produce transparent ceramics is the sintering process followed by hot isostatic pressing (HIP). Another possibility is rapid quenching of a ceramic melt to an amorphous state followed by controlled crystallization to achieve glass-ceramics. In this project a 5kW CO₂ laser has been used to produce transparent microspheres from a eutectic composition in the system Al₂O₃-Y₂O₃-ZrO₂ (AYZ) and lead-free piezoceramic from K_1-xNa_xNbO₃ (KNN) by laser fusing. A yield of 85% amorphous amount was achieved in the AYZ system and 68.5% transparent fraction in the KNN system. The median particle size of the resulting microspheres was around 85µm and 62.5µm respectively. DSC analysis has been used to determine the glass transition and crystallization temperatures. Considering these results transparent microspheres have been annealed at different temperatures to investigate the crystallization behavior. The influence of the laser power and the selected ceramic systems on the transparent fraction of microspheres and their crystallization behavior will be discussed. Increasing the transparent fraction of laser fused microspheres, manufacturing of transparent samples by isostatic pressing and sintering and the determination of properties will be future topics of interest.