Solid dielectric capacitor and method of manufacture

Claim 2

A solid dielectric capacitor comprising a dielectric ceramic body and at least two electrodes in contact therewith, the dielectric ceramic body consisting essentially of: (a) 100 parts by weight of a major ingredient expressed by the formula, (1-α{(Ba k-x M x )0 k Ti0 ₂ ) + αCaZr0 ₃ , where M is at least either of calcium and strontium; α is a numeral in the range of 0.005 to 0.040; k is a numeral in the range of 1.00 to 1.05; and x is a numeral in the range of 0.01 to 0.05; and (b) from 0.2 to 5.0 parts by weight of an additive mixture of lithi­um oxide silicon dioxide and at least one metal oxide selected from the group consisting of barium oxide, stronti­um oxide, calcium oxide, magnesium oxide and zinc oxide, the relative proportions of lithium oxide, silicon dioxide and at least one selected metal oxide constituting the additive mixture being in that region of the ternary diagram of FIG. 2 attached hereto which is bounded by lines sequen­tially connecting: the point A where the additive mixture consists of one mole percent lithium oxide, 80 mole percent silicon dioxide, and 19 mole percent metal oxide; the point B where the additive mixture consists of one mole percent lithium oxide, 39 mole percent silicon dioxide, and 60 mole percent metal oxide; the point C where the additive mixture consists of 30 mole percent lithium oxide, 30 mole per­cent silicon dioxide, and 40 mole percent metal oxide; the point D where the additive mixture consists of 50 mole percent lithium oxide, 50 mole per­ cent silicon dioxide, and 0 mole percent metal oxide; and the point E where the additive mixture consists of 20 mole percent lithium oxide, 80 mole per­cent silicon dioxide, and 0 mole percent metal oxide.

Claim 3

The solid dielectric capacitor of claim 1 wherein the elec­trodes are buried in the dielectric ceramic body.

Claim 4

The solid dielectric capacitor of claim 1 wherein the elec­trodes are of a base metal.

Claim 5

The solid dielectric capacitor of claim 3 wherein the base metal is nickel.

Claim 6

A process for the manufacture of a solid dielectric capaci­tor which comprises: (a) providing in finely divided form a mixture of: 100 parts by weight of a major ingredient expressed by the formula, (1-α){(Ba k-x M x )0 k Ti0 ₂ } + αCaZr0 ₃ , where M is at least either of calcium and stronti­um; α is a numeral in the range of 0.005 to 0.040; k is a numeral in the range of 1.00 to 1.05; and x is a numeral in the range of 0.01 to 0.05; and from 0.2 to 5.0 parts by weight of an additive mixture of lithium oxide, silicon dioxide and at least one metal oxide selected from the group consisting of barium oxide, strontium oxide, calcium oxide, magnesium oxide and zinc oxide, the relative proportions of lithium oxide, silicon dioxide and at least one se­lected metal oxide constituting the additive mixture being in that region of the ternary diagram of FIG. 2 attached hereto which is bounded by lines se­quentially connecting: the point A where the additive mixture consists of one mole percent lithium oxide, 80 mole percent silicon dioxide, and 19 mole percent metal oxide; the point B where the additive mixture consists of one mole percent lithium oxide, 39 mole percent silicon dioxide, and 60 mole percent metal oxide; the point C where the additive mixture consists of 30 mole percent lithium oxide, 30 mole percent silicon dioxide, and 40 mole percent metal oxide; the point D where the additive mixture consists of 50 mole percent lithium oxide, 50 mole percent silicon dioxide, and 0 mole percent metal oxide; and the point E where the additive mixture consists of 20 mole percent lithium oxide, 80 mole percent silicon dioxide, and 0 mole percent metal oxide; and (b) molding the mixture into desired shape and size, the molding having at least two electrode portions of an electroconduc­tive material; (c) cosintering the molding and the electrode portions to maturity in a nonoxidative atmosphere; and (d) reheating the cosintered molding and electrode portions in an oxidative atmosphere.

Claim 7

A process for the manufacture of a solid dielectric capaci­tor which comprises: (a) providing in finely divided form a mixture of: 100 parts by weight of a major ingredient expressed by the formula, (1-α){(Ba k-x M x )0 k Ti0 ₂ } + αCaZr0 ₃ , where M is at least either of calcium and stronti­um; α is a numeral in the range of 0.005 to 0.040; k is a numeral in the range of 1.00 to 1.05; and x is a numeral in the range of 0.01 to 0.05; and from 0.2 to 5.0 parts by weight of an additive mixture of lithium oxide, silicon dioxide and at least one metal oxide selected from the group consisting of barium oxide, strontium oxide, calcium oxide, magnesium oxide and zinc oxide, the relative proportions of lithium oxide, silicon dioxide and at least one se­lected metal oxide constituting the additive mixture being in that region of the ternary diagram of FIG. 2 attached hereto which is bounded by lines se­quentially connecting: the point A where the additive mixture consists of one mole percent lithium oxide, 80 mole percent silicon dioxide, and 19 mole percent metal oxide; the point B where the additive mixture consists of one mole percent lithium oxide, 39 mole percent silicon dioxide, and 60 mole percent metal oxide; the point C where the additive mixture consists of 30 mole percent lithium oxide, 30 mole percent silicon dioxide, and 40 mole percent metal oxide; the point D where the additive mixture consists of 50 mole percent lithium oxide, 50 mole percent silicon dioxide, and 0 mole percent metal oxide; and the point E where the additive mixture consists of 20 mole percent lithium oxide, 80 mole percent silicon dioxide, and 0 mole percent metal oxide; and (b) molding the mixture into desired shape and size, the molding having at least two electrode portions of an electroconduc­tive material; (c) cosintering the molding and the electrode portions to maturity in a nonoxidative atmosphere; and (d) reheating the cosintered molding and electrode portions in an oxidative atmosphere.

Claim 8

The process of claim 5 wherein the electrode portions are formed on the molding by coating the same with an electroconductive paste composed principally of a base metal.

Claim 9

The process of claim 6 wherein the base metal is nickel.

Claim 10

The process of claim 5 wherein the molding and the elec­trode portions are cosintered in a temperature range of 1050° to 1200° C.

Claim 11

The process of claim 5 wherein the cosintered molding and electrode portions are reheated in a temperature range of 500° to 1000° C.