Patent ID: 8142679

Claim:
A piezoelectric ceramic composition containing Na, Bi, Ti, Cr and O, wherein the content ratio of said Na, Bi, Ti and Cr in terms of oxides thereof falls within the following composition range (1): a Na 2 O- b Bi 2 O 3 - c TiO 2 - d CrO 3/2 (1) where a, b, c and d are mole fractions; 0.030≦a≦0.042; 0.330≦b≦0.370; 0.580≦c≦0.620; 0<d≦0.017; and a+b+c+d=1; and wherein the piezoelectric ceramic composition is substantially free of an element of group 2 of the periodic table, the piezoelectric ceramic composition has a main crystal phase of bismuth layer-structured ferroelectric, and the main crystal phase of the piezoelectric ceramic composition is of Na 0.5 Bi 4.5 Ti 4 O 15 crystal.