Abstract

ACCIARI, Heloísa Andréa; GUASTALDI, Antonio Carlos  and  BRETT, Christopher M. A.. Corrosion resistance of the phases presents in dental amalgams. Eclet. Quím. [online]. 2001, vol.26, pp. 125-142. ISSN 0100-4670.  http://dx.doi.org/10.1590/S0100-46702001000100010.

In this work, the corrosion resistance behavior of three of their phases presents in dental amalgam has been investigated: g₁-Ag₂Hg₃ (the matrix phase in the microstructure), g₂-Sn_7-8Hg (the phase most susceptible to corrosion in the oral cavity, according to the literature) and Ag-Cu eutectic (the component of the more modern powder alloys, the objective being to reduce the quantity of g₂-Sn_7-8Hg formed during the amalgamation and in this way increase its corrosion resistance). Electrochemical measurements were carried out in 0,9% aqueous sodium chloride in order to simulate the aggressivity of the oral cavity, using open circuit potential measurements, polarization curves and electrochemical impedance. The corrosion resistance exhibited by alloys can be associated with formation of a corrosion layer and seems to be dominated by the presence of a porous layer in the surface.

Keywords : dental amalgam; chloride corrosion; potentiodynamic polarization; electrochemical impedance spectroscopy (EIS).