Electrochemical Studies of the Influence of Beryllium on the Corrosion Resistance of Ni‐25Cr‐10Mo Cast Alloys for Dental Applications

Abstract

Whereas addition of beryllium into Ni‐based dental alloys can improve their casting properties, its effect on the corrosion behavior may be deleterious. The influence of beryllium addition on the corrosion resistance of Ni‐25Cr‐10Mo cast dental alloys has been investigated by different electrochemical techniques in artificial saliva and by measuring the rate of dissolution through atomic absorption spectroscopy analysis of the medium. The corrosion attack has also been examined by scanning electron microscopy. The coherent results obtained from the different techniques indicate that a low beryllium content [below 0.6 weight percent (w/o)] has no significant influence when the alloy is exposed to artificial saliva, whereas higher beryllium content results in negative effects on the corrosion resistance of the alloy. Hence, despite high content of chromium and molybdenum, the nickel‐based dental alloy is susceptible to localized corrosion attack such as pitting and crevice corrosion when the alloy contains higher levels of beryllium. This is due to the high heterogeneity of the alloys, i.e., the formation of an intermetallic phase in the eutectic structure which is susceptible to corrosion attack.