A mechanistic study of the electrochemical corrosion of the gamma 2 phase in dental amalgams. I. Evaluation of the measurements.
Conventional dental amalgams are prone to corrosion of the gamma 2 phase. In an anodic polarization experiment the presence of gamma 2 causes a current peak in the proximity of -250mV vs. SCE. Electrochemical impedance measurements carried out at this potential indicate the occurrence of an impedance curve in two parts. The high frequency part is a semi-circle with its centre below the real axis. Apart from the faradaic impedance and the double layer capacitance, the high frequency part is dominated by the behaviour of the corrosion products layer on the amalgam surface. The low frequency part has the form of a diffusion-like curve. However, since the phase angle is smaller for the above-mentioned case than for a free diffusion, this phenomenon is ascribed to diffusion in a porous layer at the interface between amalgam solution.
Lemaitre
L
L
Laboratory for Non-Ferrous Metallurgy, Rijksuniversiteit Gent, Belgium.
Moors
M
M
Van Peteghem
A P
AP
D003343:Corrosion; D003723:Dental Amalgam; D004553:Electric Conductivity; D004563:Electrochemistry; D013499:Surface Properties
D003723:Dental Amalgam