Hardening phases in some Ni-free 14 carat white gold alloys

This paper concerns 14 carats white gold alloys in which Ni, a major component of most such commercial materials but prone to cause skin allergy problems, has been substituted with other whitening elements. The aim is to analyse in detail the evolution of their microstructure and establish a link with their mechanical properties. Hardness and temperature range of precipitation are provided for the following compositions (weight%): 58.5 Au–26.5 Ag–6 Pd–2 Cu–3 Zn–4 Cr; 58.5 Au–26.5 Ag–6 Pd–2 Cu–3 Zn–4 Mn and 58.5 Au-25 Cu–8 Zn–8 Mn. The hardening phases were identified as ordered AuAg(Cu)Zn2, tetragonal CrPd like and Au3Mn like compounds.