The piezoelectric material and its manufacturing method

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PROBLEM TO BE SOLVED : To provide a piezoelectric material not including toxic lead ingredients such as PZT, and excellent in piezoelectric characteristics. SOLUTION : This method for producing a piezoelectric material is to add 0.5-3.0 wt.% at least one kind of oxides of rare earth elements selected from the group consisting of Y2O3, La2O3, Dy2O3, Nd2O3, Sm2O3, Er2O3, GdO3, Pr6O11 as ingredients for improving characteristics to a polycrystalline piezoelectric compound having a chemical composition of the formula Sr2-xCaxNaNb5O15 [wherein, (x) is 0.05-0.35]. The production method comprises (1) a mixing process for porcelain raw materials, (2) a synthesizing process, (3) a crushing process, (4) a molding process and (5) a sintering process. A firing condition in the synthesizing process is conducted e.g. in the air at 1, 050-1, 150 deg.C for 2-12 h. A firing condition in the sintering process e.g. comprises the first firing step carried out in the air at 1, 180-1, 270 deg.C for 4-8 h. and the second firing step carried out at 1, 370-1, 400 deg.C for 10-75 h.