Process for manufacturing a ceramic body having multiple barium-titanate phases
AssigneeSprague Electric Company
InventorsGaleb H. Maher, Susan E. Stefanik
Life of this patent
Estimating the term…
Abstract
A ceramic includes a dielectric ceramic body that is made by mixing powders of two barium titanate compositions of widely disparate Curie temperature with a minor quantity of a borate flux and a sintering-inhibitor such as titania or bismuth oxide. A body is formed of this start powders mixture. Upon sintering to maturity at about 1100.degree. C., the capacitor body becomes only partially co-reacted and has a dielectric constant around 2000 that varies no more than about 15% over a board operating temperature range. These properties are not a strong function of sintering conditions leading to good control at manufacturing.
Claims8
A method for making a dielectric ceramic body comprising:
- (a) forming a start mixture by mixing a first barium titanate powder A having a Curie temperature greater than 120.degree. C., a second barium titanate powder B having a Curie temperature less than 0.degree. C., from 1 to 4 weight percent of a glass borate powder C and greater than zero but less than 21/2 weight percent of a powdered sintering-inhibitor agent D, said barium titanate A being present in a quantity by weight percent that is about twice that of said barium titanate B;
- (b) forming a body of said start mixture;
- and
- (c) sintering said body to produce a dense dielectric ceramic body.
Dependencies are inferred from the claim text.