LiNbO3改性KNN基无铅压电陶瓷的制备和性能  

Studies on the Preparation and Properties of LiNbO_3 Modified KNN Lead-free Piezoelectric Ceramics

作　　者：吴浪[1] 肖定全[1] 赁敦敏[1] 朱建国[1] 余萍[1] 李香[1] 孙勇[1] 庄严 魏群 

机构地区：[1]四川大学材料科学与工程学院 [2]广州杰赛科技发展有限公司,广东广州510310

出　　处：《压电与声光》2008年第4期483-486,共4页Piezoelectrics & Acoustooptics

基　　金：国家自然科学基金资助项目(50572066);国家自然科学基金重大国际合作资助项目(50410179);教育部博士点基金资助项目(20030610035)

摘　　要：采用传统陶瓷工艺和电子陶瓷公司在工业生产中使用的原料，制备了LiNbO3改性的K0.5Na0.5NbO3基无铅压电陶瓷（KNN＋xLN，x=0～10％（摩尔分数）），并研究了陶瓷的晶相、显微结构和电性能。当x≤4％时，陶瓷为单一的正交钙钛矿结构；当x≥6％时，出现了四方钨青铜结构的K3Li2Nb5O15第二相。介电常数-温度曲线表明，随着LiNbO3含量的增加，陶瓷的正交→四方结构的相变温度TO-T向低温方向移动，而四方→立方结构的居里温度Tc向高温方向移动。当x=4％时，陶瓷具有较好的性能：相对密度达98％，压电常数d33=116pC／N，机电耦合系数kp=40．6％，剩余极化强度Pτ=21．0μC／cm^2，矫顽场Ec=0．96kV／mm，Tc=452℃。该体系陶瓷具有较高的Tc（420-495℃）和较大的kp，是一种应用前景良好的高温压电铁电材料。LiNbO3 modified K0.5 Na0. 5 NbO3 （abbreviated as KNN ＋ xLN, x = 0 - 10 %） lead-free piezoelectric ceramics have been synthesized by using the conventional mixed oxide process and electronic grade raw materials. The crystalline phase, microstructure and electric properties of the ceramics were studied. When x≤4%, the ceramics with perovskite structure possesses the orthorhombic phase, and when x ≥ 6%, a second phase of K3 Li2 Nb5 O15 with tetragonal tungsten bronze structure appears. With LiNbO3 amount increasing, the phase transition temperature （TO-T） of orthorhombic to tetragonal is shifted to the lower temperatures while the Curie temperature Tc is shifted to the higher temperatures in the dielectric constant-temperature curves. At x=4%, the optimal electric properties were obtained., piezoelectric constant d33 = 116 pC/N, planar electromechanical coupling factor kp =40.6%, remanent polarization Pr=21.0 μC/cm^2, coercive filed Ec=0.96 kV/mm, and the Curie temperature Tc = 452 ℃ respectively. The results show that KNN＋xLN is a good candidate for lead-free piezo-and ferroelectric ceramics for a wide range of temperature application because of their larger planer electromechanical coupling coefficient and higher Curie temperature.

关 键 词：碱金属铌酸盐 无铅压电陶瓷 压电性能 铁电性能 

分 类 号：TM282[一般工业技术—材料科学与工程]