| 摘要 |
PROBLEM TO BE SOLVED: To obtain ceramics which does not contain lead and has an excellent piezoelectric characteristic, more particularly a large mechanical quality coefficient (Qmax) by forming the ceramics of a bismuth layer-liek compound containing Sr, Ba, Bi and Nb, incorporating an SrBi2Nb2O9 type crystal therein and specifying an atomic ratio Ba/(Sr+Ba). SOLUTION: The atomic ratio is 0<Ba/(Sr+Ln)<=0.2. The entire part compsn. of the ceramics is merely required to be specified to (Sr1-xBax)Bi2Nb2O9 and may deviate therefrom. For example, the ratio of Sr+Ba to Nb or the ratio of Bi to Nb may deviate by about ±5% from the stoichiometric composition. The crystal grain of the ceramics is a bobbin or needle shape and the average crystal grain size thereof is 1 to 10 μm in a major axis direction. The Curie point of the resulted ceramics is >=300 deg.C and is sufficiently high for practicable use. Qm may be made to at >=1000 near 4.5 MHz by specifying the substitution rate of Ba to an adequate value. |
