Piezoelectric ceramics, and piezoelectric element, and electronic equipment containing piezoelectric ceramics

Abstract

Provided is a lead-free piezoelectric ceramics having enhanced mechanical quality factor (Qm) and mechanical strength. The piezoelectric ceramics, includes at least a first crystal grain and a second crystal grain. The first crystal grain has an average equivalent circle diameter of 2 μm or more and 30 μm or less. The first crystal grain includes a perovskite-type metal oxide represented by the following general formula (1) as a main component, and the second crystal grain includes a perovskite-type metal oxide represented by the following general formula (2) as a main component: (1) xBaTiO 3 -yCaTiO 3 -zCaZrO 3 ; and (2) x′BaTiO 3 -y′CaTiO 3 -z′CaZrO 3 , provided that x, y, z, x′, y′, and z′ satisfy x+y+z=1, x′+y′+z′=1, 0≦x′≦0.15, 0.85≦y′≦1, 0≦z′≦0.05, x>x′, 0<y<y′, and z>0.

1 . (canceled) 
     
     
         2 . A piezoelectric ceramics, comprising:
 a first crystal grain including an oxide containing Ba, Ca, Ti, and Zr; and   a second crystal grain including an oxide containing Ca and Ti;   wherein the second crystal grain contain a larger amount of Ca than the first crystal grain,   wherein an average equivalent circle diameter of the first crystal grain is larger than an average equivalent circle diameter of the second crystal grain, and   wherein when the piezoelectric ceramics is polished, a ratio of an area of the first crystal grain in a polished surface of the piezoelectric ceramics is larger than a ratio of an area of the second crystal grain in the polished surface.   
     
     
         3 . The piezoelectric ceramics according to  claim 2 , wherein the average equivalent circle diameter of the second crystal grain is 200 nm to 2 μm. 
     
     
         4 . The piezoelectric ceramics according to  claim 2 , wherein the average equivalent circle diameter of the first crystal grain is 2 μm to 30 μm. 
     
     
         5 . The piezoelectric ceramics according to  claim 2 , wherein the first crystal grain contains Mn in an amount of 0.05% by weight to 0.40% by weight. 
     
     
         6 . The piezoelectric ceramics according to  claim 2 , wherein 0.85≦y′≦1.00, where y′ is a ratio of a mole number of Ca to a sum of a mole number of Ba and Ca in the second crystal grain. 
     
     
         7 . A piezoelectric element, comprising:
 a first electrode;   the piezoelectric ceramics according to  claim 2 ; and   a second electrode.   
     
     
         8 . A multilayered piezoelectric element, comprising a piezoelectric ceramic layer and an electrode layer, which are alternately stacked,
 wherein the piezoelectric ceramic layer comprises the piezoelectric ceramics according to  claim 2 .   
     
     
         9 . An electronic equipment, comprising the piezoelectric element according to  claim 7 . 
     
     
         10 . An electronic equipment, comprising the multilayered piezoelectric element according to  claim 8 .