Compositions: ceramic – Ceramic compositions – Titanate – zirconate – stannate – niobate – or tantalate or...
Patent
1992-02-27
1993-06-15
Bell, Mark L.
Compositions: ceramic
Ceramic compositions
Titanate, zirconate, stannate, niobate, or tantalate or...
501139, C04B 3546
Patent
active
052198111
ABSTRACT:
To produce a modified barium titanate ceramic which is semiconductive and sufficiently high in breakdown voltage and has a low specific resistance at room temperature and a high positive temperature coefficient (PTC) of resistance, the invention provides a powder composition comprising (A) a basic mixture consisting of 45-85 mol % of BaTiO.sub.3 powder, 1-20 mol % of SrTiO.sub.3 powder, 5-20 mol % of CaTiO.sub.3 powder and 1-20 mol % of PbTiO.sub.3 powder, (B) a source of a dopant element such as Nb, Sb, Y, La or Ce to render the ceramic semiconductive, (C) a source of Mn such as MnC.sub.2 O.sub.4 and/or a source of Cu such as CuO added such that the total amount of Mn and Cu is not more than 0.06 mol % on the basis of the quantity of the mixture (A) with proviso that the amount of Mn is not more than 0.025 mol % and (D) SiO.sub.2 amounting to 0.1-2.0 mol % on the basis of the quantity of the mixture (A). The BaTiO.sub.3 powder and the SrTiO.sub.3 powder are produced by calcining BaTiO(C.sub.2 O.sub.4).sub.2 and SrTiO(C.sub.2 O.sub.4).sub.2, respectively, and in each of these powders very fine primary particles agglomerate to constitute porous and coarse secondary particles (about 100-200 .mu.m). The PbTiO.sub.3 powder may be produced by calcining PbTiO(C.sub.2 O.sub.4).sub.2 so as to have nearly the same structure as the BaTiO.sub.3 and SrTiO.sub.3 powders. The aimed ceramic is produced by compacting the powder composition into a green body and sintering it at 1300.degree.-1400.degree. C.
REFERENCES:
patent: 2758911 (1956-08-01), Lyod et al.
patent: 3441517 (1969-04-01), Brauer et al.
patent: 3975307 (1976-08-01), Matsuo et al.
patent: 4101454 (1978-07-01), Kulwicki et al.
patent: 4483933 (1984-11-01), Kobayashi et al.
patent: 4764494 (1988-08-01), Sakabe et al.
patent: 4820670 (1989-04-01), Sano et al.
patent: 4987107 (1991-01-01), Narumi et al.
"Ceramics", vol. 5, No. 11 (1970), pp. 68-76 H. Sasaki partial translation.
Japanese Abstract JP 61-146710 A (Jul. 4, 1986).
Enomoto Takamitsu
Kawahara Midori
Murata Noboru
Okada Naoki
Ueda Hiroshi
Bell Mark L.
Central Glass Company Limited
Jones Deborah
LandOfFree
Powder composition for sintering into modified barium titanate s does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Powder composition for sintering into modified barium titanate s, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Powder composition for sintering into modified barium titanate s will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1042567