Electrochemical Behavior of Alloys for Fixed Partial Denture

ABSTRACT

The electrochemical behaviors of eight parent alloys and four post-solder alloys used in dental prostheses were specified in a (pH=7.4; [NaCl]=9g/L)-aqueous solution at 37°C. For each alloy, the free potential was followed during two hours, and a cyclic polarization between the cathodic domain and the solvent’s oxidation was performed. The galvanic corrosion between each parent alloy and its usual post-solder was also studied. The free potentials stay in the immunity domain of the alloy’s base-elements (precious metals) or in their passivation domain (nickel, chromium). A relatively strong oxidation of the alloys is possible only for high values of applied potential. Corrosion of the noblest alloys is almost inexistent. It occurs for the nickel-base alloys but it is very slow. Most of the elements present can be oxidized, but only for high potentials which cannot be really achieved by dissolved oxygen. Galvanic corrosion can occur between the parent alloy and the post-solder alloy in some cases.

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