Bulk metallic glasses are a relatively novel class of materials which exhibit improved hardness over conventional crystalline alloys, high elasticity, lower casting temperatures, minimal shrinkage on casting, and thermoplastic formability. This translates into much-improved wear resistance without the need for extensive hot working, high definition near-net-shape casting, and processability via methods usually reserved for polymers and conventional oxide glasses. Consequently, bulk metallic glasses based on precious metals should be of significant interest for jewelry. However, issues regarding the abnormal tarnishing of 18K gold-based bulk metallic glasses remain. Hence, further research is still needed to preserve their desirable luster.

Bulk metallic glasses based on precious metals were discussed previously at the 2007 Santa Fe Symposium® by B. Lohwongwatana and at the 2013 Santa Fe Symposium by U. Klotz. Here, more recent developments are reported, alongside current research into tarnishing and further potential avenues of research.

Author: Owain S. Houghton