A preliminary investigation of the electrochemical properties of a nitrided stainless steel for dental applications.

A comparison has been made of the electrochemical behaviour of investment cast coupons of a 20Cr, 25Ni, Ti stabilized stainless steel (in the nitrided and un-nitrided conditions) with a cobalt-chromium alloy in order to make a preliminary assessment from the point of view of corrosion of the nitrided material for dental and other biomedical applications. Electrochemical tests have been carried out in vitro in artificial saliva and in Ringer's solution, with some additional tests carried out in natural saliva. Both the potential-time behaviour and the magnitude of the breakdown potential on anodic polarization suggest that the protective properties of the passivating film are substantially improved in the case of the nitrided stainless steel alloy.