Various gold alloys are used in the jewellery industry, as alloying additions improve the hardness and contribute to colour variations in gold-based materials. AMD has been involved in research and development of a number of gold alloys over the years:
- 18 ct hard gold for watches, clasps, collars, bracelets, watch straps, etc. in the European market.
- 22 ct hard gold with hardness values comparable to those of conventional 18 ct gold alloys.
- 24 ct hard gold: a 995 purity alloy that can be hardened to a hardness comparable to the hardness of cold worked commercial 91.7 wt% gold and almost double the maximum hardness that can be achieved in pure gold.
- 18 ct white gold with little palladium and no nickel as an alternative to existing commercial 18 ct white gold alloys.
- Purple gold: an 18 ct alloy of purple colour that can be used as gemstone inlays.
- Spangold: a novel family of 18 ct gold alloys that exhibit a unique natural texture, or ‘spangle’, on their surfaces.
AMD does not only focus on gold jewellery alloys, but also on other precious metals like platinum. AMD has developed Platigems, a high platinum-content compound that can be cast to shape-forming gems of different colours.
With alloy engineering being one of AMD’s core competencies, it is in a position to assist with the development of jewellery alloys for specific applications.
Equipment is on-site for full metallurgical characterisation, and good relationships with third parties enable AMD to evaluate different manufacturing techniques.
AMD has published in prestigious journals like Gold Technology and Gold Bulletin and presented work at the Santa Fe Symposium for Jewelry technology.