Abstrakt

Study of a dental cobalt-base alloy used in prosthetic dentistry part 2: electrochemical properties

Anne-Sophie Corroy, Patrice Berthod, Pascal De March

The dental alloys for frameworks destined to strengthen prostheses as bridgesmust be not onlymechanically resistant, but also corrosion resistant. After having characterized itsmicrostructure and itsmechanical and thermophysical properties in the first part of this work, the same dental cobalt-base alloywas here tested in corrosion.Mounted as working electrode in a threeelectrodes cell containing a {9g/LNaCl; pH=7.4} aqueous solution simulating saliva heated to human body temperature, this cobalt alloy was subjected to Stern-Geary, Tafel and cyclic polarization experiments. Added to the open circuit potential evolution over two hours, these electrochemical tests demonstrated that the alloy passivated rather rapidly and thereafter well behaved in corrosion. The obtained polarization resistanceswere very high, and the determined corrosion current densities very low. They were of the same levels as for nickel-base alloys characterized in similar artificial saliva.