PIEZOELECTRIC PORCELAIN COMPOSITION

摘要

PROBLEM TO BE SOLVED: To provide a piezoelectric porcelain composition giving stabilized piezoelectric properties as a piezo-resonator and a vibrator material by developing a piezoelectric ceramic having a large frequency constant. SOLUTION: This piezoelectric porcelain composition is represented by the formula xNa(Nb1-a Taa )O3 -yK(Nb1-a -Ta1 )O3 -zM(Nb1-a Taa )2 O3 (M is at least one of alkaline earth metal where x+y+2z=1) and a, b, x and y in the formula are defined in the following ranges: 0.0<=a<=0.5; 0.2<=x<=0.98, 0.0<=y<=0.78; 0.01<=z<=0.4. At least one of compounds containing first row transition metal may be added to the composition so that its content becomes 0.01-1.8wt.%. The piezoelectric ceramics obtained from the objective composition has a large frequency constant, a large mechanical quality factor and a good electromechanical coupling factor.