Corrosion resistance of three types of Co–Cr dental alloys manufactured by casting and selective laser melting

Abstract

The aim of this study was to investigate the corrosion resistance of three types of Co–Cr alloys manufactured by casting or selective laser melting (SLM). Six Co–Cr dental alloys were classified into three different types according to their formulation (containing Mo, W, or both as alloying elements) and according to the manufacturing process, namely, casting or SLM. Then the electrochemical properties were characterized by Anodic Polarization Scanning (AS) and Electrochemical Impedance Spectroscopy (EIS) in Ringer's and 0.1 M NaCl +0.1 M lactic acid solutions. E _corr , I _corr , E _pit , and corrosion rate (CR) were estimated by AS and statistically analyzed ( α  = 0.05). The EIS data fitted to a Randles circuit. Electrochemical testing revealed statistically significant differences for E _corr and E _pit among the alloys tested in the same solution, whereas no differences were identified in I _corr or CR. The Nyquist plots exhibited semicircular profiles, indicating that the electrochemical response was predominantly controlled by charge transfer processes. For all groups, CR was found much higher in the acidic 0.1 M lactic acid + 0.1 M NaCl solution than in Ringer's one. The results of this study showed that CR depended on the solution rather than alloy type or manufacturing process.