A precious metal alloy is an alloy based on one of the metals in a precious metal and composed of other elements. Precious metal alloys have the main properties of precious metals. For their specific USES, they have better comprehensive physical, chemical and mechanical properties than single precious metals, as well as high reliability, stability and long life. Gold platinum alloy was obtained in 1763. In 1802, the hydrogen and oxygen blowing pipe was invented, which provided a high temperature means of smelting precious metal alloy. By 1847, all precious metals except osmium and ruthenium could be smelted. After 1892, electric arc furnace and induction furnace appeared successively, and the melting technology of precious metals and their alloys was greatly developed. These two furnaces are still the main smelting equipment for precious metals. By the end of 1930s, more than 50 platinum group metal alloys were available for use. The precious metal alloys are widely used in various industrial sectors. Since the 1970s, continuous ingot casting, extrusion, composite (including coating) and other technologies have been gradually applied in the precious metal alloy industry. China has a long history in the production of gold, silver and their alloys (see history of metallurgy); Production of platinum group metal alloys began in small batches in 1964. Since then, the scale and variety of research and production have gradually expanded. By the end of 1970s, China had produced about 200 kinds of precious metal alloys and more than 1,000 kinds of profiles of various specifications.
Precious metal alloys are almost all used as functional materials. There are several classification methods for precious metal alloys: silver base alloy, gold base alloy, platinum base alloy and palladium base alloy can be divided into base metal. According to the application can be divided into electric contact alloy, alloy, resistance alloy, resistance strain alloys, elastic alloys, magnetic alloys, catalyst, hydrogen through material, tube leakage cathode materials and glass fiber board, vessels and crucible materials, decoration materials, filler metals alloy, dental materials and metal COINS (see metal coin), etc. The application characteristics of precious metal alloys are as follows: small (batch and quantity), small (volume of single articles and components), fine (high technical requirements, often used in key parts), wide (almost all modern scientific and technological fields and industrial production departments need) and expensive.
