Corrosion Resistance of Co-Cr Alloys Manufactured by Different Techniques

Objectives: The objective of this study was to investigate the electrochemical corrosion resistances of Co-Cr alloy samples that were manufactured in artificial saliva (Fusayama-Meyer) by using conventional casting, CAD-CAM milling, and laser sintering techniques.
Methods: The samples fabricated by using three different techniques were examined by potentiodynamic test and electrochemical impedance spectroscopy (EIS). After the potentiodynamic test, the amount of ions released into the artificial saliva was estimated and subsequently, the results were statistically analyzed. Furthermore, the sample surfaces were investigated before and after tests using scanning electron microscopy.
Results: With the investigation of ion release, potentiodynamic tests, EIS and SEM imaging revealed that the corrosion resistances of the samples manufactured by milling and laser sintering were higher comparing to those of the samples produced by conventional casting. The samples of the conventional casting group showed varying corrosion resistance, which was presumably due to the alloy constituents.
Conclusions: The corrosion resistance of the Co-Cr samples manufactured by CAD-CAM milling and laser sintering were higher than those of the casted samples. The cast Co-Cr samples also differed from one another in terms of corrosion resistance.