烧结方法对LiTaO_3/Al_2O_3复相陶瓷微观组织及力学性能的影响

Effect of sintering method on microstructure and mechanical properties of LiTaO_3/Al_2O_3 dual phase ceramics

为了研究铁电 /压电陶瓷颗粒对结构陶瓷力学行为的影响规律及机理 ,分别采用真空热压烧结法和冷等静压成型无压烧结法制备了稳定共存的LiTaO3/Al2 O3(LTA)复相陶瓷 ,对比研究了其微观组织与力学性能 .结果表明 ,15 0 0℃真空热压烧结制备的LTA复相陶瓷中 ,LiTaO3 相熔化 ,冷却时分布在Al2 O3 基体晶界 ,基体晶粒粗化 ,力学性能较低 ;2 0 0MPa冷等静压成型 ,130 0℃无压烧结制备的LTA复相陶瓷中 ,LiTaO3 颗粒弥散分布 ,基体晶粒细小 ,φ(LiTaO3)为 5 %的LTA复相陶瓷的力学性能显著改善 ,强韧化机理为细晶与压电效应和

In order to study the effect of ferroelectric/piezoelectric ceramic particles on mechanical properties of structural ceramics and its mechanisms, compatible LiTaO 3/Al 2O 3 (LTA) dual phase ceramics were fabricated by hot sintering, isostatical pressing and then pressureless sintering. The microstructure and mechanical properties of these materials were investigated comparatively. In LTA dual phase ceramics hot pressed at 1 500 ℃, the LiTaO 3 phase was melted and then located at the grain boundaries of Al 2O 3 matrix after cooling. The grain size of Al 2O 3 matrix increases greatly and the mechanical properties of LTA dual phase ceramics decrease. While in LTA dual phase ceramics cold isostatically pressed under a pressure of 200 MPa and then pressurelessly sintered at 1 300 ℃, the LiTaO 3 particles are distributed in the Al 2O 3 matrix homogenously. The grain size of Al 2O 3 matrix is much smaller. The mechanical properties of LTA dual phase ceramic dispersed with 5 vol%LiTaO 3 piezoelectric particles are greatly improved, where fine grains and the energy dissipation due to piezoelectric effect or/and domain wall motion are suggested as strengthening and toughening mechanisms.