工艺条件对KNNT陶瓷性能的影响

采用传统固相反应法制备了(K0.5Na0.5)(Nb0.7Ta0.3)O3(KNNT)无铅压电陶瓷。通过XRD、SEM分析方法分别研究了预烧后粉体和烧结后样品的晶体结构和微观形貌,以及预烧、烧结条件对样品性能的影响。结果表明,预烧后的粉体和烧结后的样品的晶体结构分别为四方相和斜方相;在860～920℃预烧,选择合适的烧结温度均可获得性能优异的陶瓷样品。较佳工艺条件为900℃预烧、1180℃烧结,样品d33可达到205pC/N,kp、k33分别为45.9%、60.5%。

Influences of process conditions on properties of (K0.5Na0.5)(Nb0.7Ta0.3)O3 ceramics

Lead-free piezoelectric ceramics of (K0.5Na0.5)(Nb0.7Ta0.3)O3 (KNNT) were prepared by the conventional solid -state reaction technique. The microstructures of the calcined powder and the sintered samples were characterized by XRD and SEM methods,respectively. The influence of calcining and sintering condition on the electrical properties of KNNT ceramics was investigated. The results show that the crystal structures of the calcined powder and the sintered samples are tetragonal and orthorhombic phase,respectively. In the calcined temperature range of 860～920 ℃,all the specimens sintered at their optimum temperature reveal optimized piezoelectric properties (d33≈200,kp≈45 %). The KNNT ceramics,which are calcined at 900 ℃ and then sintered at 1 180 ℃,show the best piezoelectric properties of d33≈205 pC/N,kp≈45.9 % and k33≈60.5 %,respectively. This process condition may be the optimum one for the KNNT composition.