PIEZOELECTRIC PORCELAIN AND ITS PRODUCTION

摘要

PROBLEM TO BE SOLVED: To produce a piezoelectric porcelain having a high electromechanical coupling factor, undergoing easy control of the temp. coefft. of resonance frequency and less liable to vary resonance frequency after a thermal shock. SOLUTION: The piezoelectric porcelain comprises grains of two or more perovskite type compds. different from each other in piezoelectric characteristics. Each of the perovskite type compds. has >=45% electromechanical coupling factor Kps and at least one of the compds. has <=0.5% variation ΔFrs of resonance frequency when it receives a thermal shock at 25-280 deg.C.