FERROELECTRIC CERAMIC MATERIAL HAVING STRONG PIEZOELECTRIC CHARACTERISTIC AND ITS PRODUCTION

摘要

PROBLEM TO BE SOLVED: To obtain a ceramic material to be readily poled, having strong piezoelectric characteristics by doping lead niobate whose lead is partially substituted with Ba in a specific ratio with Bi and La in a specified ratio.;SOLUTION: This ferroelectric ceramic material comprises lead niobate which is shown by the general formula (x is 0.4-0.6; y is 0.01-0.03; z is 0.01-0.03), whose lead is partially substituted with Ba and which is doped with Bi and La and has a high d33 value. Bi and La are doped only at a lead position and a barium site remains without being disarranged. Oxides of Pb, Ba, La, Bi and Nb are mixed in a fixed ratio in 4-6% excessive amount of lead oxide and calcined at 800-900°C for 2-6 hours. The formed product is cooled, ground, mixed with a binder into a pellet, sintered in the air at 1,250-1,280°C for 1-1.5 hours to form a sintered disk. Both the sides of the disk are coated with a silver paste, fired and subjected to poling by corona discharge to give the objective ferroelectric ceramic material.;COPYRIGHT: (C)2001,JPO