Corrosion Characteristic of Vitallium 2000 CoCrMo Casting Alloy in Fluoride Containing Artificial Saliva

In order to reveal the effect of fluoride ions (F−) on the passive film corrosion resistance and composition of CoCrMo dental prosthesis. The passivity of casting Vitallium 2000 CoCrMo series alloy was systematically studied by adopting electrochemical and surface techniques. The results show that F− have a certain effect on the passive film corrosion resistance of casting CoCrMo in oral environment, and the increase of F− concentration weakens the passive film corrosion resistance. With the increase of F− concentration, the open circuit potential moves negatively, the corrosion current density increases, the polarization resistance decreases, and the defect density in the passive film increases. With the extension of immersion time, the corrosion resistance of alloy will be enhanced and shows: AS > AS + 0.5 wt% NaF > AS + 1 wt% NaF. The addition of F− can decrease Co, Cr and Mo peaks sharply and promote the dissolution of the passive film. The result of present study could regulate and guide the application dose of oral fluorine-containing products.