Investigation of fracture toughness of modified (K_xNa_{1 鈭?#xa0;x})NbO₃ lead-free piezoelectric ceramics

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• 作者：Ezgi D. Yilmaz ; Henry E. Mgbemere ; Hü ; seyin &Ouml ; zcoban ; Rodrigo P. Fernandes ; Gerold A. Schneider ; ^{g.schneider@tu-harburg.de} ;
• 关键词：Fracture ; Toughness and toughening ; Dielectric properties ; Niobates ; Lead-free ceramics
• 刊名：Journal of the European Ceramic Society
• 出版年：2012
• 期刊代码：53_09552219
• 类别：ms
• 出版时间：September, 2012
• 卷：32
• 期：12
• 页码：3339-3344
• 文件大小：1176 K

摘要

While most of the previous studies have focused on the processing and electrical properties of KNN-based ceramics, very little research has been carried out to evaluate their mechanical behavior. This work presents for the first time an examination of the fracture toughness, K_IC, of the most widely studied (K_xNa_{1 鈭?#xA0;x})NbO₃ (KNN)-based lead-free ceramics modified with lithium, tantalum and antimony. The samples were produced through the conventional mixed-oxide route and the K_IC values were measured using the single edge V-notched beam (SEVNB) method under four-point bending. The mean K_IC values were determined to be 0.48 卤 0.18 MPa m^1/2 for (K_0.48Na_0.48Li_0.04)NbO₃, 0.8 卤 0.18 MPa m^1/2 for (K_0.5Na_0.5)(Nb_0.9Ta_0.1)O₃, 0.86 卤 0.04 MPa m^1/2 for (K_0.48Na_0.48Li_0.04)(Nb_0.9Ta_0.1)O₃ and 1.06 卤 0.21 MPa m^1/2 for (K_0.48Na_0.48Li_0.04)(Nb_0.86Ta_0.1Sb_0.04)O₃ compositions. The microstructure, phase structure and dielectric constant values of the samples have been used to correlate the results of the K_IC values.