Tarnish and corrosion behaviour of palladium-silver alloys

Binary and commercial Pd--Ag dental alloys show a greatest resistance to both tarnish and corrosion at compositions of between 50-75% Ag, most probably due to saturation of the d-electron shell in this composition range. The commercial Pd--Ag alloys have more corrosion resistance, but a lower tarnish resistance than the binary Pd--Ag alloys, due in part to the minor alloying with indium or Zn. The addition of Cu increases the segregation of Ag, which adversely affects both tarnish and corrosion resistance. A solutionization heat treatment degrades tarnish resistance, but does not affect corrosion resistance. 42 ref.--AA