A conclusion to research undertaken in 1999 that analyzed failures in silicon-containing low-karat investment casting alloys, this paper concentrates on identifying the deleterious phases and proposing mechanisms for their formation and for the overall failure of the casting. For the study, a 10K yellow gold investment casting alloy from the Au-Ag-Cu-Zn system was analyzed in order to determine the effect of silicon additions and composition changes on performance during investment casting. Additions of silicon and varying the Ag-Cu-Zn ratio were determined to affect the formation of the phases and the subsequent performance of the alloy during solidification and devesting. Armed with this information, the jewelry caster can make informed decisions regarding the devesting process when casting high-silicon/low-karat gold alloys.

Author: Stewart Grice