The casting temperatures of 950 palladium-based alloys are normally above 1550°C. For this reason, those who cast platinum alloys may apparently have the advantage. However, the physical characteristics of Pd alloys are significantly different from those of Pt alloys. Experience with Pd dental alloys, which have been successfully used for more than 25 years, has been helpful. Even though the maximum Pd content of Pd dental alloys is generally 750 ‰, the difficulties are broadly similar to those of jewelry alloys. Taking this experience into account, this work aims to summarize the main problems arising from Pd alloys in investment casting. In particular, the possible interactions between Pd, oxygen, carbon and hydrogen are investigated. Hot tearing and ductility loss, typical of these alloys, are discussed as well as the role of the main secondary elements present in commercial alloys. The technical knowledge acquired with dental alloys suggests procedures that can help the goldsmith manufacture 950 Pd alloys.

Author: Paolo Battaini