Effects of palladium on the thermal behavior of the γ1-phase of the Ag-Sn-Cu dental amalgam

Effects of the addition of 1 weight percent (w/o) palladium on the thermal behavior of a lathe-cut type of high copper amalgam (13 w/o copper) were studied. Two identical alloys, with and without 1 w/o palladium were fabricated. X-ray diffraction studies of these amalgams have revealed the elimination of the γ₂-phase by palladium addition. DSC thermograms of non-palladium-containing alloy indicated the existence of two γ₁-phases, one with the transition temperature at 88 °C and the other at 109 °C. Aging for 18 months at 37 °C cannot eliminate the presence of the γ₁-phase which has a low transition temperature. The addition of 1 w/o palladium into amalgam produced a more thermally stable amalgam.