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In vitro chloride corrosion behaviour of Dispersalloy
Author(s) -
SARKAR N. K.,
GREENER E. H.
Publication year - 1975
Publication title -
journal of oral rehabilitation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.991
H-Index - 93
eISSN - 1365-2842
pISSN - 0305-182X
DOI - 10.1111/j.1365-2842.1975.tb01524.x
Subject(s) - corrosion , eutectic system , polarization (electrochemistry) , anode , chloride , amalgam (chemistry) , alloy , materials science , ageing , current density , chemistry , metallurgy , analytical chemistry (journal) , electrode , chromatography , physics , quantum mechanics , biology , genetics
Summary The in vitro chloride corrosion behaviour of Dispersalloy has been investigated by anodic polarization as a function of time after trituration (ageing) and compared with conventional dental amalgam. Dispersalloy is a commercial alloy containing a mechanical mixture of Ag 3 Sn and Ag–Cu eutectic in the ratio 2:1. From measurement of 1 h corrosion potentials it was observed that over a time period of 1 year Dispersalloy became appreciably more noble (potential shift from –500mV to – 350 mV Vs. SCE), whereas the corrosion potential of conventional amalgam remains unchanged. Initial anodic polarization profiles for Dispersalloy indicated presence of y 2 and Cu 6 Sn 5 phases as evidenced by presence of the –250 mV peak. However, the current density associated with this peak was about three times less than that of conventional amalgam. As a function of ageing time the polarization profile is shifted in the direction of decreasing current density and after 1 year the –250 mV peak is absent. The anodic polarization profile of conventional amalgam is unchanged after 1 year. The improved corrosion resistance of Dispersalloy is attributed to the formation of Cu 3 Sn as a function of time due to solid state reaction between Ag–Cu eutectic and y 2 .