친환경 비납계 Sodium potassium niobate 압전세라믹스의 조성 최적화

다국어 초록 (Multilingual Abstract)

Lead-free piezoelectric [(Na0.5K0.5)1-x(A)x][(Nb)1-y-z(B)y(Mn)Z]O3 (A:Ag or Li, B=Ta) specimens prepared by the conventional ceramic processing. Their crystal structure, microstructure, dielectric and piezoelectric properties were investigated with different compositions (substituents and contents). Electrical properties of the specimens increased up to 0.075 mol Ag or Li addition and Ta addition improved their piezoelectric properties. The maximum values, d33, Qm, kp obtained were 153(pC/N), 351, 0.43 for Ag/Ta and 201(pC/N), 141, 0.4 for Li/Ta based NKN systems, respectively. When 0.005 mol Mn was added in Ag/Ta or Li/Ta based specimens, dielectric loss was effectively suppressed below 1.5% and piezoelectric constant, d33 was improved, although dielectric constant and Qm were somewhat lowered. These results were explained in terms of the formation of morphotropic phase boundary, sinterability, grain size, formation of oxygen vacancy and change of transition temperature.