LEAD-FREE PIEZOELECTRIC PORCELAIN COMPOSITION, PIEZOELECTRIC CERAMIC COMPONENT FORMED USING THE COMPOSITION, AND PROCESS FOR PRODUCING PIEZOELECTRIC CERAMIC COMPONENT

摘要

Provided is an alkali-niobate-based piezoelectric porcelain composition which has a crystal-structure transition point in the range of operation guarantee temperatures and which, despite this, is inhibited from abruptly changing in capacitance. The piezoelectric porcelain composition comprises Li, Na, K, Nb, Ta, Sb, and O as major constituent elements and has an alkali-niobate-based perovskite structure. When the composition has an ABO₃ type perovskite structure as a unit lattice in which Z=1, the composition has a transition point at which the crystal structure changes from the monoclinic to the tetragonal system. Thus, the composition has a crystal-structure transition point at -50ºC to 150ºC so as to utilize the high piezoelectric effect produced by the MPB at the crystal-structure transition point and, despite this, has the feature of always satisfying ΔC0.