Abstract: A process for making a finished or semi-finished article of silver alloy, said process comprising the steps of providing a silver alloy containing silver in an amount of at least 77 wt %, copper and an amount of germanium that is preferably at least 0.5 wt % and is effective to reduce tarnishing and/or firestain, making or processing the finished or semi-finished article of the alloy by heating at least to an annealing temperature, gradually cooling the article; and reheating the article to effect precipitation hardening thereof. The avoidance of quenching reduces the risk of damage to the article.

Abstract: A master metal composition adapted for alloying with silver to give an alloy containing at least 77 wt % Ag and at least 0.5 wt % Ge comprises Cu, Ge and boron together with any further ingredients for said alloy and any impurities. It further provides a process for making silver alloy containing silver in an amount of at least 77 wt % Ag, 1-7.2 wt % Cu copper, at least 0.5 wt % Ge and B together with any further ingredients for said alloy and any impurities, comprising the step of melting together fine silver and a master metal composition which is at least a ternary alloy of copper, germanium and boron, e.g. 92.5-92.8 wt % Ag, 6.0-6.3 wt % Cu, about 1.2 wt % Ge and 1-15 ppm boron as grain refiner. The resulting silver alloy exhibits good tarnish and firestain resistance and can exhibit significant precipitation hardening on gradual air cooling.

Abstract: Silver alloys containing copper and germanium e.g. about 1 wt % Ge and of very low copper content e.g. about 0.8 wt % Cu can be precipitation hardened to 65 HV or above, whereas alloys of similar copper content and not containing germanium remain soft. In an embodiment, a silver alloy comprises 92.5-97 wt % Ag, 1-4.5 wt % Cu, 0.4-4 wt % Zn, 0.8-1.5 wt % Ge, 0 to 0.2 wt % Si, In or Sn and 0-0.2 wt % Mn, the balance being boron as grain refiner, incidental ingredients and impurities. The said alloy preferably comprises boron as grain refiner added as a boron hydride, e.g. sodium borohydride. A further group of alloys comprises a ternary alloy of silver, copper and germanium containing from more than 93.5 wt % to 95.5 wt % Ag, from 0.5 to 3 wt % Ge and the remainder, apart from incidental ingredients (if any), impurities and grain refiner, copper, the grain refiner being sodium borohydride or another boron hydride. Silicon-containing casting grain that gives rise to bright as-cast products is also disclosed.

Abstract: Disclosed for use in treating a metal, e.g., an alloy of silver as aforesaid, is a water-based composition comprising a treatment agent selected from an alkanethiol, alkyl thioglycollate, dialkyl sulfide or dialkyl disulfide and at least one of an amphoteric, nonionic or cationic surfactant in a concentration that is effective to solubilise the treatment agent. Preferably the composition comprises at least a non-ionic relatively hydrophobic surfactant e.g. cocamide DEA. The composition is particularly suitable for the treatment of Ag—Cu—Ge alloys.

Abstract: A process is provided for making a finished or semi-finished article of silver alloy, said process comprising steps of: providing a silver alloy containing silver in an amount of at least 77 wt %, copper and an amount of germanium that is at least 0.5 wt % and is effective to reduce tarnishing and/or firestain; making or processing the finished or semi-finished article of the alloy by heating at least to an annealing temperature; and gradually air cooling the article from the temperature at which it is made or processed to develop a Vickers hardness of more than 70.

Abstract: The present invention relates to silver solder or brazing alloys and to their use in making soldered joints in various grades of silver, particularly silversmithing grades. They alloys are of the Ag—Cu—Zn family containing at least 55 wt % Ag and from 0.5 to 3 wt % Ge. Additional alloys are silver solders or brazing alloys of the Ag—Cu—Zn family containing more than 70 wt % Ag and from 0.5 to 3 wt % Ge. They can exhibit an advantageous combination of colour, flowability and corrosion resistance. A method is also provided of making a joint in Sterling silver which includes using a silver solder or brazing alloy of the Ag—Cu—Zn family containing 10-30 wt % Cu, 8-15 wt % Zn, from 0.5-3 wt % Ge, optionally 0.05-0.4 wt % Si, optionally 1-3 wt % Sn, optionally 1 ppm-0.3 wt % B, the balance being 55-77 wt %, Ag, said solder being a colour match for said Sterling silver.

Abstract: A method for silver chain manufacture comprises forming lengths of silver wire into successive chain links whose ends abut using an automatic chain forming machine, and closing the links by brazing or welding abutting ends thereof, by means or a laser. The wire comprises at least 92.5 wt % Ag and about 0.5aboul 3 wt % Gc and speeds of 100-250 links per minute can be achieved. The invention also relates to a silver chain.