LEAD-FREE PIEZOELECTRIC CERAMIC COMPOSITION, PIEZOELECTRIC ELEMENT USING SAME, PRODUCTION METHOD FOR LEAD-FREE PIEZOELECTRIC CERAMIC COMPOSITION

摘要

Provided is a lead-free piezoelectric ceramic composition having high piezoelectric properties. The lead-free piezoelectric ceramic composition fulfils a molar ratio (Na/K) for Na (sodium) and K (potassium) in the main phase thereof of 0.40 < (Na/K) < 3.0. In addition, the main phase has a crystal structure wherein (i) a first spot group corresponding to a basic grating cycle and (ii) a second spot group, corresponding to the twice the grating cycle of the basic grating cycle and being weaker than the first spot group, appear in an electron beam diffraction image obtained by using a transmission electron microscope and by having an electron beam incident from the <100> direction when the main phase is expressed as a pseudo cubic crystal.