Method for joining materials together by a diffusion process using silver ...

1. A method for joining two elements using a silver based alloy having a germanium content, comprising:

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, the remainder principally being copper apart from any impurities, which alloy contains elemental boron as a grain refiner at a concentration of greater than 0 parts per million and less than 20 parts per million;

placing the two elements 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; and

heating the two free surfaces 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.

2. A method according to claim 1, where the germanium content comprises from about 0.5 to about 3% by weight.

3. A method according to claim 1, where both elements to be joined comprise the silver/germanium alloy.

4. A method according to claim 1, wherein the two adjacent free surfaces of the elements are heated to as low as a temperature of 500.degree. C.

5. A method according to claim 1, where the element comprising a silver based alloy having a germanium content is a powder, plating or a thin coating.

6. A method according to claim 1, when used in the manufacture of items of jewelry, silverware or electrical or electronic contacts, or aerospace materials.

7. A method according to claim 1, wherein a plurality of superimposed elements are joined together to create a multi-layered product.

8. A silver/germanium alloy 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.

9. A silver/germanium alloy having a silver content of at least 77% by weight, a germanium content of between 0.5 and 3% by weight, the remainder being copper apart from any impurities, which alloy contains boron as a grain refiner at a concentration of greater than 0 parts per million and less than about 20 parts per million.

10. A method for joining two elements using a silver based alloy having a copper and a germanium content, which method comprises:

providing two elements to be joined together, at least one of the elements consisting essentially of 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, the remainder principally being copper apart from any impurities, which alloy contains elemental boron as a grain refiner at a concentration of greater than 0 parts per million and less than 20 parts per million;

placing the two elements 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; and

heating the two free surfaces 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.

11. A method according to claim 10, wherein the germanium content comprises between 0.5 and 3% by weight.

12. A method according to claim 10, wherein both elements to be joined comprise the silver/copper/germanium alloy.

13. A method according to claim 10, wherein the two adjacent free surfaces of the elements are heated to as low as a temperature of 500.degree. C.

14. A method according to claim 10, wherein the silver/copper/germanium alloy is selected from the group consisting of: a powder; plating; and a thin coating of the silver/copper/germanium alloy.

15. A method according to claim 10, when used in the manufacture of items selected from the group consisting of jewelry, silverware, electrical and electronic contacts, and aerospace materials.

16. A method according to claim 10, wherein a plurality of superimposed elements are joined together to create a multi-layered product.

17. An alloy consisting essentially of a silver/copper/germanium alloy, the alloy having a silver content of at least 77% by weight, a germanium content of between 0.4 and 7% by weight, the remainder being copper apart from any impurities, which alloy contains elemental boron as a grain refiner at a concentration of greater than 0 parts per million and less than 20 parts per million.

18. An alloy according to claim 17, wherein the germanium content comprises between 0.5 and 3% by weight.

19. An alloy according to claims 17, wherein the elemental boron content is less than 10 parts per million.

20. An alloy according to claim 17, wherein the elemental boron content is about 1 part per million.

21. An alloy according to claim 17, wherein the boron is provided by a master copper/boron alloy having a boron content of about 2 percent by weight.