Back to results
US 4,397,886 AGranted
Method for making a ceramic intergranular barrier-layer capacitor
AssigneeSprague Electric Company
InventorsStephen M. Neirman, Ian Burn
Life of this patent
Estimating the term…
Abstract
A donor modified strontium titanate formulated to become conductive when sintered in air, is further modified with a minute quantity of manganese and sintered to maturity in a nitrogen atmosphere. A paste including silver particles, and oxides of bismuth and copper is applied to two major portions of the body. The coated body is heated at about 920.degree. C. to oxidize the grain boundaries and to form silver electrodes tightly adhered to the body.
Claims5
A method for making a ceramic intergranular barrier layer type capacitor comprising:
- (a) preparing a ceramic start mixture consisting essentially of strontium, titanium, a strontium-titanate-donor and manganese, said donor being selected from large cations A, small cations B and combinations thereof, said start mixture being adjusted to form during sintering a strontium titanate ceramic compound, ##EQU5## wherein x, y and w are the atomic proportions, respectively, of said donor cations having a charge of +3, +5 and +6, so that both charge balance and large/small cation balance may be established by strontium vacancies, ##EQU6## therein, wherein x+y+w is from 0.003 to 0.021 and wherein z lies between 0.00005 and 0.0025;
- (b) forming a body of said mixture;
- (c) sintering said body in an inert atmosphere to maturity;
- and
- (d) forming a mixture of oxidizing agents and silver particles, applying a coat of said mixture to selected surface portions of said sintered body, and heating said coated body at a temperature of about 900.degree. C.
2 more elements
Dependencies are inferred from the claim text.