| 摘要 |
PROBLEM TO BE SOLVED: To ensure a high mechanical Q value by heat-treating lead titanate- base ceramics at a specified temp. in an atmosphere under a partial pressure of oxygen below atmospheric pressure between firing and polarizing processes. SOLUTION: Starting materials such as PbO, TiO2 , CaCO3 , SrCO3 and BaCO3 , are mixed in a prescribed ratio, calcined, pulverized, compacted and fired at 1,000-1,400 deg.C to obtain a piezoelectric ceramic substrate represented by the formula (1-a) [PbxTiO3 ]+a[MeTiO3 ] (where Me is Ca, Sr or Ba, 0.95<=x<=1.02 and 0.01<=a<=0.35). This substrate is held at 500 deg.C to the firing temp., preferably at 600-1,000 deg.C in an atmosphere under a partial pressure of oxygen below atmospheric pressure and the temp. is reduced at 200-300 deg.C/hr rate. The substrate is then polarized by applying an electric field of 1-10 kV/mm at 80-150 deg.C in silicone oil, etc., to form the objective piezoelectric ceramic element. |
