Corrosion behaviour of FePt-based bulk magnets in artificial saliva solution

Bulk hard magnetic FePt-based alloys are proposed as new materials for dental applications. In this study the corrosion behaviour of bulk Fe50Pt50, Fe35Pt35P30 and Fe53Pt44C3 magnets prepared by spark plasma sintering of mechanically milled powders is evaluated in artificial saliva solution at 37 °C in dependence on their exposure time and in comparison to that of other relevant dental alloys by means of electrochemical polarisation measurements and scanning electron microscopy. The alloys exhibit in this environment a platinum-like behaviour and thus, they are highly stable also during long-term exposure. Enhanced corrosion activity does not occur when coupling these alloys with commercial dental alloys of Fe- and CoCr-based. A particular low-corroding state is attained in combination with the dental spring steel Fe–18Cr–18Mn–2Mo–1N.