Gold jewelry brazing

Solders and brazes for jewelry gold alloys are usually gold—silver—copper alloys that can be modified to yield a desired melting range by adjusting the silver-to-copper ratio. Additions of zinc, cadmium, tin, or nickel compensate for the changes in color introduced by compositional modification (87). 

The fluxes used with both silver and gold jewelry brazes are standard formulations, nsed also in industrial brazing. The most common fluxes used with gold brazing alloys are based on sodium tetraborate (Na2B407 IOH2O), commonly known as borax, which is fluid above 760°C, applied in the form of a paste. 

Gold is unusual in that it is the only element on which both brazes and solders are based. However, because gold is the most expensive constituent of solders and brazes, the use of gold filler alloys tends to be limited to high value applications, such as electronics, photonics, and jewelry manufacture. 

Lower melting point gold-based brazing alloys may be classified into two groups, according to the application. There are the karat gold brazes, which are mostly used in the jewelry trade, and others that were developed to address the needs of other application sectors, such as the electronics, nuclear power, and aerospace industries [29]. These types of gold-based brazes will be discussed in turn. 

G. Normandeau, 1989. Cadmium-free gold brazing alloys. In Proceedings of the Santa Fe Symposium on Jewelry Manufacturing Technology, ed. D. SchneUer, 179-209. Albuquerque, NM Met-Chem Research. 

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