| 摘要 |
PROBLEM TO BE SOLVED: To obtain a porcelain composition having a high deflective strength, having a high P/V value in a lead-free piezoelectric material and capable of controlling the temperature coefficient of capacitance in a dielectric material by incorporating at least Sr, Ca, Na, Ba, K and Nb as metallic elements and specifying the contents of Sr4Na2Nb10O30, Ca4Na2Nb10O30 and Ba2KNb5O15. SOLUTION: When the molar ratio composition of the porcelain composition is represented by the formula xSr4Na2Nb10O30.yCa4Na2Nb10O30.zBa2KNb5O15, (x), (y) and (z) are within the range defined by segmentsly connecting points A(x=97.40, y=2.50, z=0.10)-B(x=64.90, y=35.00, z=0.10)-C(x=48.75, y=26.25, z=25.00)-D(x=73.12, y=1.88, z=25.00)-A in the x-y-z ternary diagram. The porcelain composition has such piezoelectric characteristics as a P/V value of >=40dB, can arbitrarily control the temperature coefficient of capacitance at -40 to +80 deg.C in the range from -8, 450 to +230 ppm/ deg.C and maintains a high four-point bending strength of >=180 Mpa. |
