MANUFACTURE OF HIGH-MOLECULAR PIEZOELECTRIC BODY

摘要

PURPOSE:To manufacture a thick piezoelectric body having high performance by bringing an electromechanical coupling factor Kt at a time when a molded shape consisting of a copolymer of vinylidene fluoride and ethylene trifluoride at predetermined ratios is poled through heat treatment at a prescribed treatment temperature to a fixed value or more. CONSTITUTION:A molded shape composed of a copolymer of 65-95mol% vinylidene fluoride and 35-5mol% ethylene trifluoride or a polymer mainly comprising the copolymer is thermally treated at a treatment temperature T = (a crystal transition temperature T'm-5) - (a melting-point temperature T'm) [ deg.C]. A high-molecular piezoelectric body having a not less than 0.05% electromechanical coupling factor Kt obtained through poling after heat treatment or while being thermally treated is acquired. Accordingly, an excellent thick piezoelectric body proper to an ultrasonic vibrator is acquired.