Corrosion characteristics of a selective laser melted Co–Cr dental alloy under physiological conditions

This study explores the corrosion behavior of a dental cobalt–chromium (Co–Cr) alloy fabricated by selective laser melting (SLM) under conditions simulating the oral environment. Specimens were fabricated using either SLM or traditional casting methods. Microstructure and surface characteristics were evaluated using X-ray photoelectron spectroscopy (XPS), scanning electron microscopy and X-ray diffraction. In addition, sample corrosion characteristics were assessed using electrochemical impedance spectroscopy. Large microstructural differences were observed between SLM and traditional cast samples, with SLM exhibiting a more compact and homogeneous microstructure. The SLM samples also exhibited a slightly thicker surface oxide layer in comparison to traditional cast samples. In artificial saliva at pH 5, no differences were observed in the electrochemical corrosion properties or XPS surface characteristics of SLM and traditional cast specimens. However, in artificial saliva at pH 2.5, significant differences in electrochemical corrosion properties were observed, with SLM specimens exhibiting more corrosion resistance in comparison to traditional cast samples. The enhanced corrosion resistance of SLM samples in an acidic environment provides further support for their use in dental applications, where the oral environment can become temporarily acidic after meals.