Changes of hardness and electrical conductivity of white gold alloy Au-Ag-Cu after aging treating

Golden alloys which are able of strengthening after tempering, i.e. artificial aging, play an increased role in jewel production. According to customer's demands these alloys are produced as "yellow" or white" gold. Commonly an alloy of 585 finesse, i.e., 58.5 wt.% of pure gold, is used. In the appropriate literature most authors have investigated rather yellow gold than white gold. In fact, the white gold alloys are more complex in their nature than yellow alloys. In this paper the changes after precipitation (age) hardening of a white gold alloy with chemical composition corresponding to Au585Ag65Cu277Zn16Pd57 are examined. The hardening of this alloy after aging at high temperature plays an important role in improving jewel quality. So, it is possible to produce a jewel either by hand- or machine making, beginning from an initial soft alloy (easily deformed and shaped) into a final product with increased hardness and strength. This aim could be realized by applying a rather simple heat-treatment, which includes. annealing or non-hardening quenching. A jewel produced from white gold is hardened and strengthened after a period of time. Special attention was paid to the analysis of the changes in hardness and electrical conductivity in real time regimes, which are attainable during production in a gold shop. The used temperatures were from room temperature up to recrystallization temperatures.