## Facts

- Walter L. Hack filed a patent application (No. 208,449; Jan. 29, 1951) claiming a brazing alloy made of gold, copper, and nickel for use at elevated temperatures and under high vacuum (e.g., vacuum-tube work).
- Only claims 3 and 5 remained in the application on appeal. They claimed the alloy composition as a product:
  - Claim 3: a brazing alloy “composed entirely of approximately 35% by weight of gold, approximately 62% by weight of copper, and approximately 3% by weight of nickel.”
  - Claim 5: a brazing alloy “composed entirely of gold, copper and nickel” with 25–50% gold and 1–5% nickel, described as having low surface tension, low vapor pressure, flowability, and fine crystalline structure.
- Hack’s specification stated that adding nickel to gold-copper alloys produced better flow and a fine crystalline structure that reduced leakage when used in vacuum equipment joints.
- The PTO examiner finally rejected claims 3 and 5, and the Board of Appeals affirmed. Hack took an ex parte appeal to the United States Court of Customs and Patent Appeals.
- The PTO relied on prior art including:
  - Nelson (U.S. Patent No. 2,426,467), showing gold-copper alloys used as solders in vacuum-tube assembly.
  - Peterson (U.S. Patent No. 2,164,938), disclosing gold-copper alloys containing small amounts of cobalt as a regulator of grain size and discussing nickel’s known behavior in gold alloys.
  - A German patent (No. 575,257) cited to show that cobalt and nickel were treated as equivalents in gold-copper alloys.
- A key point in the dispute was that the gold-copper-nickel composition Hack claimed was already disclosed in the art (even if not described there as a “brazing alloy”), while Hack’s application sought the composition as a new product rather than a claim limited to a new use.

## Issues

1. Whether Hack’s claims to a gold-copper-nickel alloy were patentable as a new composition of matter when the same composition was disclosed in the prior art, though not identified there for brazing use.
2. Whether, in view of prior teachings of gold-copper solders and gold-copper-cobalt alloys plus art-recognized cobalt/nickel equivalence, selecting nickel in comparable amounts was within ordinary skill rather than an inventive advance.
3. Whether asserted operating characteristics (flowability/low surface tension and fine crystalline structure for vacuum work) could support a product claim when the composition itself was already taught in the prior art.

## Decision

- The C.C.P.A. affirmed the Board of Appeals.
- Claims 3 and 5 remained rejected; the court held the claimed alloy composition was not patentable over the prior art.

## Legal Principles

- A product (composition) claim is not patentable merely because the applicant identifies a new use or newly recognized properties of a composition that is already known in the prior art.
- Where prior art teaches substantially the same alloy system and indicates functional interchangeability of alloying elements (here, cobalt and nickel) for similar metallurgical purposes (such as grain-size regulation), substituting one for the other in similar amounts is generally within ordinary skill.
- Descriptive claim language reciting intended use or functional characteristics (e.g., “for use under high vacuum,” “flowability,” “fine crystalline structure”) does not confer patentability if the underlying composition is old or would have been obvious from the art.

## Conclusion

The C.C.P.A. upheld the PTO’s rejection because the gold-copper-nickel composition Hack claimed was already disclosed in the prior art, and the references also supported treating nickel and cobalt as equivalents in gold-copper alloys used to obtain desired structural and performance results. Hack’s characterization of the alloy as a brazing material for high-vacuum applications, and his discussion of favorable properties in that context, did not convert an already-known composition into a patentable new product.


Application of Hack, 44 C.C.P.A. 954, 245 F.2d 246, 114 U.S.P.Q. 161 (1957)