Patent Number: 6,168,071

Title: Method for joining materials together by a diffusion process using silver/germanium alloys and a silver/germanium alloy for use in the method

Abstract: A method for joining two elements using a silver-based alloy having a germanium content is described. The method comprises providing two elements to be joined together, at least one of the elements comprising a silver/copper/germanium alloy having a silver content of at least 77% by weight, a germanium content of between 0.4 and 7% by weight, typically from about 0.5% to about 3%, the remainder principally being copper apart from any impurities. The alloy also contains boron as a grain refiner at a concentration of greater than 0 parts per million and less than 20 parts per million, more typically less than about 10 parts per million, with working embodiments including boron in an amount of about 2 parts per million. The two elements are placed adjacent one another such that a portion of a free surface of the silver/copper/germanium alloy contacts a portion of a free surface of the other element without interposing a filler material between the two free surfaces. The two free surfaces are heated where the two elements are adjacent one another to a temperature below that of the solidus temperature of any one of the constituent materials of the elements, thereby joining the two elements by a diffusion process. A silver/germanium alloy also is described having a silver content of at least 77% by weight and a germanium content of between 0.4 and 7% by weight, which alloy contains boron as a grain refiner at a concentration of greater than 0 parts per million and less than 20 parts per million.

Inventors: Johns; Peter Gamon (Watford, Herts WD1 3BQ, GB)

Assignee: Johns; Peter Gamon

International Classification: B23K 35/30 (20060101); C22C 5/06 (20060101); B23K 020/00 (); C22C 005/00 ()

Expiration Date: 01/02/2018