In the mid-1990s several jewelry industry publications asserted the need for platinum alloy improvements. Authors noted that existing alloy compositions were too soft, too difficult to cast without porosity, and too time consuming to polish. Since then, only a limited amount of alloy development has taken place, and there is wide agreement among jewelry manufacturers and retailers that these previously identified problems still largely exist today. This research is intended to explore the casting quality of mainstream North American platinum alloys, together with a new alloy that attempts to address the shortcomings found in these alloys. Metallurgical results will be reportd for 95Pt5Ru, 95Pt5Co, 90Pt10lr, and a number of 950Pt alloys containing elements that substantially increase hardness. Characteristics to be assessed include sources and patterns of internal porosity, surface hardness, and the metallurgical effects of thermal post-processing of castings.

Authors: Teresa Fryé, Dr. Jörg Fischer-Bühner