Small additions of elements such as Iridium, Cobalt, or Indium act as grain refiners in fourteen karat gold alloys. Typically, the greater the addition the finer the grain size within generally accepted metallurgical boundaries. It has also been shown that one of the two primary deoxidants used in investment casting, Silicon (Boron being the other), has a grain enlarging effect as its concentration is increased. This research will combine the grain refiner with the deoxidant and evaluate the effect of one property enhancer on the other.

The effect of alloy compositional changes will also be included in conjunction with the property enhancer variations. Attempts were made to include a wide range of Silver-Copper ratios as actual compositions used in practice vary from user to user. The Zinc level was maintained at a constant level.

Finally, a study of the grain refiners and deoxidants versus major alloying compositional changes was made. The color of the alloy was held as close to constant as possible. The Silver Zinc ratio was maintained as literature dictates to maintain color.

Author: Timo Santala