# US 4,400,310 A · Thick film silver compositions for silver terminations for reduced barium titanate capacitors

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- Number: US 4,400,310 A
- Document ID: US4400310A
- Status: Granted
- Kind: A
- Application number: 06/120,839
- Filed: 1980-02-12
- Granted: 1983-08-23
- Earliest claimed: 1980-02-12
- Assignees: E. I. Du Pont de Nemours and Company
- Inventors: K. Manikantan Nair
- Web page: https://patentgrep.com/patent/US4400310A

## CPC

- H01G 4/0085: {Fried electrodes}
- C22C 32/0089: {with other, not previously mentioned inorganic compounds as the main non-metallic constituent, e.g. sulfides, glass}
- H01G: CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE (selection of specified materials as dielectric H01B3/00; capacitors having potential barriers H10D1/62, H10K10/10)
- C22C: ALLOYS (treatment of alloys C21D, C22F)

## Abstract

Thick film silver compositions, containing silver powder, glass and certain inorganic materials, useful for silver terminations for reduced barium titanate (RBT) capacitors, are provided. The inorganic materials or their precursors contain ions capable of substituting into the BaTiO.sub.3 lattice, existing as surface layers on the RBT bodies, or grains therein, to produce (Ba.sub.1-x M.sub.x ') (Ti.sub.1-y M.sub.y ")(O.sub.3-z A.sub.z) where x<1, y<1, and z<0.1. When terminated with these thick film silver compositions, RBT capacitors have excellent dielectric properties.

## Claims

### Claim 1

A thick film silver composition consisting essentially of a dispersion in an organic vehicle of:
(A) 30-90 parts by weight, based on the weight of the dispersion, of silver powder;
(B) 1-20 parts by weight, based on the weight of the dispersion, of glass having a softening point below 600.degree. C. and an absolute viscosity at the firing temperature of less than 10.sup.6 ; and
(C) 0.1-30 parts by weight, based on the weight of the dispersion, of inorganic material or precursor thereof containing one or more ions (M', M" or A) capable of substituting into a BaTiO.sub.3 lattice to produce compounds of the type
(Ba.sub.1-x M.sub.x ') (Ti.sub.1-y M.sub.y ") (O.sub.3-z A.sub.z),
wherein
M' is selected from the group consisting of Ca.sup.+2, Ba.sup.+2, Sr.sup.+2, Pb.sup.+2, Rb.sup.+2, Cs.sup.+2 and Fe.sup.+3 ;
M" is selected from the group consisting of Ge.sup.+4, Ti.sup.+4, Zr.sup.+4, Zn.sup.+2 and Cr.sup.+3 ;
A is F.sup.- ; and
x<1, y<1 and z<0.1.

### Claim 2 (depends on 1)

A thick film silver composition consisting essentially of the composition of claim 1 in which (A) is 45-70 parts by weight, (B) is 1-10 parts by weight, and (C) is 1-10 parts by weight of the composition.

### Claim 3 (depends on 1)

The composition of claim 1 wherein the silver powder is present to the extent of 45-70 parts.

### Claim 4 (depends on 1)

The composition of claim 1 wherein the glass is present to the extent of 1-10 parts parts.

### Claim 5 (depends on 1)

The composition of claim 1 wherein the glass is lead bismuth borate.

### Claim 6 (depends on 1)

The composition of claim 1 wherein the precursor of the inorganic material is devitrifiable glass.

### Claim 7 (depends on 6)

The composition of claim 6 wherein the devitrifiable glass is lead germinate.

### Claim 8 (depends on 6)

The composition of claim 6 wherein the devitrifable glass is present together with the inorganic material.

### Claim 9 (depends on 1)

A reduced barium titanate capacitor terminated with the silver composition of claim 1.