| 摘要 |
PROBLEM TO BE SOLVED: To obtain a piezoelectric porcelain compsn. having a relatively high electromechanical coupling factor, hardly changing in electrical characteristics even at a soldering package temp. and hardly changing in resonance frequency due to a temp. cycle by adding a specified amt. of Cr2 O3 and/or Mn3 O4 as a subsidiary component to a principal component represented by a specified relation. SOLUTION: A mixture is prepd. by adding 0.05-0.8 wt.% Cr2 O3 and/or Mn3 O4 as a subsidiary component to 100 wt.% principal component represented by the formula Pb(1-3/2α+β) Ndα (B1 B2 )XTiYZrZO3 and mixing them. The mixture is molded and fired to obtain a sintered body. Electrodes for polarization are formed on the surface of the sintered body, the sintered body is plarized by applying a DC electric field of >=3.0 kV/mm at 130-180 deg.C and a short circuit is caused between the electrodes. The sintered body is then heat-treated at 150-250 deg.C under such conditions that the product of the heat treatment temp. ( deg.C) and heat treatment time (hr) is made >=1,800. In the formula, 0.02<=α<=0.08, 0.002<=β<=0.05, 0.02<=X<=0.05, 0.46<=Y<=0.73, 0.25<=Z<=0.49, X+Y+Z=1 and B1 and B2 are each Nb, Ta, Sb or Sn with the exception of B1 ≠B2 and a combination of (Sb, Sn). |
