LEAD-FREE PIEZOELECTRIC CERAMIC COMPOSITION, METHOD FOR PRODUCING SAME, PIEZOELECTRIC ELEMENT USING LEAD-FREE PIEZOELECTRIC CERAMIC COMPOSITION, ULTRASONIC PROCESSING MACHINE, ULTRASONIC DRIVE DEVICE, AND SENSING DEVICE

摘要

This lead-free piezoelectric ceramic composition is mainly composed of a first crystal phase (KNN phase) and a second crystal phase (NTK phase). The first crystal phase (KNN phase) is composed of a plurality of crystal grains that are formed of an alkali niobate/tantalate perovskite oxide having piezoelectric characteristics, said crystal grains being bonded with each other in a deposited state. The second crystal phase (NTK phase) is composed of a compound that contains titanium (Ti), and the spaces between the crystal grains in the first crystal phase are filled with the second crystal phase (NTK phase).