This paper concludes the discussion on age hardenable gold jewelry alloys. In our presentation at the 2009 Santa Fe Symposium, we reviewed hardenable colored karat golds, discussed hardening mechanisms in Au-Ag-Cu-Zn alloys and their compositional limits, color variation and mechanical properties. The benefits of using hardenable colored gold alloys, including the possibility of manufacturing lightweight jewelry, are equally applied to white golds as well. The metallurgy of white-gold alloys, however, is different because, in addition to Au, Ag, Cu, and Zn, these alloys contain a significant amount of such whitening elements as Ni and/or Pd. The subject of Ni-containing white golds can be found in literature, whereas there is practically no data on Pd-containing white golds even though they show much easier processing, better workability and resistance to corrosion. We discuss 14K Pd-white hardenable gold alloys' color and mechanical properties in terms of Pd/Cu and Ag/Cu ratios.

Authors: Greg Raykhtsaum, Dr. D.P. Agarwal