Patent number: 5954994
Abstract: Improved are the piezoelectric characteristics of conventional ceramics of (Ba.sub.1-x Sr.sub.x).sub.2 NaNb.sub.5 O.sub.15 where 0.ltoreq.x.ltoreq.1, and provided is a novel piezoelectric ceramic composition which does not contain lead and which can be practiced industrially as a material for piezoelectric ceramic devices such as piezoelectric ceramic filters, etc. The piezoelectric ceramic composition comprises, as the essential component, a ceramic component of the general formula, (1-y)(Ba.sub.1-x Sr.sub.x)Nb.sub.2 O.sub.6 --yNaNbO.sub.3 where 0.ltoreq.x.ltoreq.1 and 0.15.ltoreq.y<1/3. Preferably, the composition contains, as the side component, at least one oxides of Mn, Cr, W, Si, Mo, Ni, Co, Sn, Mg, Sb, Ti, Zr and Fe, in a total amount of not larger than about 5% by weight in terms of MnO.sub.2, Cr.sub.2 O.sub.3, WO.sub.3, SiO.sub.2, MoO.sub.3, NiO, Co.sub.2 O.sub.3, SnO.sub.2, MgO, Sb.sub.2 O.sub.3, TiO.sub.2, ZrO.sub.2 and Fe.sub.2 O.sub.3, respectively.
Type:
Grant
Filed:
February 24, 1998
Date of Patent:
September 21, 1999
Assignee:
Murata Manufacturing Co., Ltd.
Inventors:
Masahiko Kimura, Tadahiro Minamikawa, Akira Ando