Silver is a metallic substance with the highest electrical conductivity and thermal conductivity of any metal. It is also soft, malleable and ductile. The silver-white metal is lustrous and is used for jewelry, coinage and tableware, such as spoons, forks, and knives. Silver has been mined throughout the world and is known to have excellent resistance to corrosion.
For many years it has been usual to alloy copper with silver for the purpose of strengthening it and making it more suitable for articles such as coins, utensils and watch springs. The new alloys of which the present invention is a development are distinguished by their much greater hardness and tensile strength than were possessed by the old silver-copper alloys. They are unaffected by exposure to air and by acids, and can be made remarkably hard and pliable without losing their white color.
The addition of a small quantity of aluminum increases the hardening effect of silver on a copper base and reduces its sensitivity to stress-corrosion cracking. The improved corrosion resistance of these alloys can be further enhanced by a further small amount of aluminum or other alloying elements.
These alloys are very much in demand in the metallurgical industry and for ornamental use. They are also a valuable ingredient in the manufacture of electric power iron towers, storage tanks, electric wire and cables, metal stents, capacitors, transportation equipment and aircraft. In addition, they are the main material for the production of silver-zinc primary batteries and secondary batteries for cameras and clocks.