The introduction of Precious Metal Clay (PMC) in 1991 allowed jewelry and other objects of fine silver and gold to be made in a new way that has inspired the jewelry arts community. These original fine silver and gold clays could be sintered in a simple air atmoshphere furnace but lacked the strength of alloyed precious metal. Most silver and gold jewelry is made from alloys containing copper, which cannot be fired in air because of oxidation. This presentation will show how new high-strength PMC was developed using copper oxide (not copper!) in powder metallurgy, which was found to be useful for improving the chemical stability of the clay and for easy firing of the organic binder, even in bulky pieces. The jewelry industry is always looking for something new. This new range of accepted jewelry alloys in PMC makes it possible for mainstream manufacturers, as well as artists, to consider the possibility of further innovation in jewelry design and manufacture.

Authors: Shinji Otani, Takashi Yamaji, Yoshifumi Yamamoto