# US 4,396,577 A · Cobalt-palladium-silicon-boron brazing alloy

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- Number: US 4,396,577 A
- Document ID: US4396577A
- Status: Granted
- Kind: A
- Application number: 06/310,270
- Filed: 1981-10-09
- Granted: 1983-08-02
- Earliest claimed: 1981-10-09
- Assignees: General Electric Company
- Inventors: Murray S. Smith, Jr.; Mark S. Hilboldt; Pracheeshwar S. Mathur
- Web page: https://patentgrep.com/patent/US4396577A

## CPC

- B23K 35/3046: {Co as the principal constituent}
- B23K 35/322: {a Pt-group metal as principal constituent}
- B23K: SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM

## Abstract

A brazing alloy, particularly suited for use in high temperature gas turbine engines has a composition range which exhibits X-ray inspection capability, adequate stress rupture properties, ductility and oxidation resistance. The brazing alloy composition consists essentially of about 25-95% Pd, up to about 5% Si, up to about 3.5% B, balance being Co and incidental impurities, all percentages being by weight. The brazing alloy is capable of brazing in the 1800.degree.-2100.degree. F. temperature range and is less costly than current Au-bearing brazing alloys currently in use for brazing in this temperature range.

## Claims

### Claim 1

An improved brazing alloy consisting essentially of, by weight, 25-95% Pd, up to 5% Si, up to 3.5% B, balance being Co and incidental impurities, the Si, when selected, being at least about 2%, and the B, when selected, being at least about 0.5%, said brazing alloy having a liquidous temperature in the range of about 1800.degree.-2100.degree. F. and being characterized by the substantial absence of Ag, Ti, Mn, Cu, and P.

### Claim 2 (depends on 1)

The brazing alloy of claim 1 in which the Co is 37-38%, Pd is 59-60%, Si is 2-3% and B is 0.5 to 1%, said brazing alloy having a liquidus temperature of about 1965.degree. F.

### Claim 3 (depends on 1)

A brazing alloy of claim 1 in which the Co is 19-68%, Pd is 30-80% and B is up to about 2%, the alloy being further characterized by the substantial absence of Si.

### Claim 4 (depends on 3)

The brazing alloy of claim 3 in which the Co is about 19%, Pd is about 80%, and B is up to about 1%, said brazing alloy having a liquidus temperature in excess of about 1925.degree. F.

### Claim 5 (depends on 3)

The brazing alloy of claim 3 in which the Co is about 68%, Pd is about 30%, and B is up to about 2%, said brazing alloy having a liquidus temperature in excess of about 1925.degree. F.

### Claim 6 (depends on 1)

The brazing alloy of claim 1 in which the Co is 7-35%, Pd is 60-90%, and Si is 3-5%, the alloy being further characterized by the substantial absence of B.

### Claim 7 (depends on 6)

The brazing alloy of claim 6 in which the Co is 15-17.5%, Pd is about 80%, and Si is 2.5-5%, said brazing alloy having a liquidus temperature in excess of about 1950.degree. F.

### Claim 8 (depends on 6)

The brazing alloy of claim 6 in which the Co is about 7%, Pd is about 90% and Si is about 3%, said brazing alloy having a liquidus temperature in excess of about 2000.degree. F.

### Claim 9 (depends on 1)

The brazing alloy of claim 1 wherein said alloy is in the form of powder.

### Claim 10 (depends on 1)

The brazing alloy of claim 1 wherein said alloy is in the form of a brazing foil.

### Claim 11 (depends on 3)

The brazing alloy of claim 3 wherein said alloy is in the form of a wire.