Electrochemical study of corrosion in Ni-Cr dental alloys.

The anodic behaviour of Ni-Cr dental alloys used as porcelain substrates has been investigated in both as-cast and thermal treated conditions. Polarization curves and scratching at constant potentials in synthetic salivas have shown that breakdown potentials are not influenced by the elimination of passive films covering the samples. Thermal treatments used to reproduce the microstructure of the alloys in dental crowns have not shown detectable effects on the electrochemical behaviour. Selective corrosion occurs by dissolution of Ni-rich interdendritic regions formed during solidification.