Patent ID: 6458180
Filing Date: 2002-10-01
Classification: A61K,B22F,C22C

Abstract:
An amalgamatable dental alloy powder for making an amalgam having a low initial mercury vapor release rate having a composition comprising 50-80 wt % Ag; 10-30 wt % Cu, and 10-35 wt % Sn, and optionally less than 7 wt % of Pd, and having a particle size ranging from 1 to 100 microns with a majority thereof having a particle size less than 45 microns, which is prepared by a process comprising the following steps i) and ii), or steps I), II), and III):i) subjecting a single-alloy powder having a particle size ranging from 1 to 55 microns with a majority thereof having a particle size less than 20 microns to a heat treatment A; said single-alloy powder comprising 50-80 wt. % Ag, 10-30 wt. % Cu, 10-35 wt. % Sn and optionally less than 7 wt. % Pd; ii) subjecting the heat treated single-alloy powder to a pickling treatment; I) subjecting a Agâ€”Cuâ€”Sn powder having a particle size ranging from 1 to 70 microns with a majority thereof having a particle size less than 30 microns to a heat treatment B, and subjecting a Agâ€”Cuâ€”Pd powder having a particle size ranging from 1 to 100 microns with a majority thereof having a particle size less than 45 microns to a heat treatment C; II) subjecting the heat treated Agâ€”Cuâ€”Sn powder and the heat treated Agâ€”Cuâ€”Pd powder to a pickling treatment; and III) mixing the resulting Agâ€”Cuâ€”Sn powder and the resulting Agâ€”Cuâ€”Pd powder obtained from step II) to form an amalgamatable dental alloy having a composition comprising 50-80 wt. % Ag, 10-30 wt. % Cu, 10-35 wt. % Sn and optionally less than 7 wt. % Pd; wherein said heat treatments A, B and C independently comprise heating said powder at a temperature ranging from 100 to 600Â° C. in an inert atmosphere for a period ranging from 0.5 hours to 8 days, provided that said powder remains in a powder form or in a loose agglomerate form after said heat treatment.