| 摘要 |
PURPOSE:To improve the mechanical quality coefficient and electromechanical coupling coefficient of the title piezoelectric ceramic composition by substituting a part of Pb of the three-component solid soln. consisting essentially of the zirconium-lead titanate of specified composition for the Ca, Sr, and Ba in a specified molar ratio. CONSTITUTION:A part of the Pb of the three-component solid soln. consisting of Pb(Ca1/4Mn1/4Nb1/2)O3-PbTiO3-PbZrO3 is substituted for >= 1 kind of element (Me) selected from a group of Ca, Sr, and Ba. Consequently, the piezoelectric ceramic composition shown by the formula (Pb1-aMea)[(Ca1/4Mn1/4 Nb1/2)xTiyZrz]O3 is formed. In the formula, (a), (x), (y), and (z) denote molar ratios, (x+y+z)=1, (a) <=0.20, (x) is 0.01-0.2, (y) is 0.33-0.54, and (z) is 0.37-0.63. The mechanical quality coefficient and electromechanical coupling coefficient are simultaneously increased by the composition, and the dielectric constant is also increased. The composition is appropriately used for a powerful ultrasonic oscillator. |
