| 摘要 |
PROBLEM TO BE SOLVED: To enable low temp. firing and to reduce a change of resonance frequency due to a temp cycle by replacing part of Pb in a specified compsn. by Ca, Sr or Ba to prepare a principal component and incorporating a specified amt. of Cr2 O3 or Mn3 O4 as a subsidiary component. SOLUTION: A principal component is prepd by replacing 1-10 mol.% of Pb in a compsn. of the formula (where 1.00<=α<=1.04, 0.01<=A<=0.12, 0.02<=B<=0.15, 0.30<=C<=0.65, 0.25<=D<=0.68 and A+B+C+D=1) by at least one among Ca, Sr and Ba, and 0.05-1.2 wt.% at least one of Cr2 O3 , and Mn3 O4 is added as a subsidiary component to the principal component. They are mixed and the mixture is compacted and fired. Polarization electrodes are formed on the resultant sintered compact and a DC electric field of >=3.5 kV/mm is applied at about 130-180 deg.C to polarize the sintered compact. The sintered compact is then heat-treated at 220-280 deg.C while keeping a short-circuited state between the electrodes. The relative dielectric constant can suitably be regulated in accordance with a device. |
