Attractive force of castable iron-platinum magnetic alloys.

OBJECTIVE: The objective of this study was to examine the attractive force of cast Fe-Pt alloys of varying compositions to dental iron-neodymium-boron magnets. METHODS: Ingots of Fe-40 at%Pt, Fe-38 at%Pt, Fe-37 at%Pt and Fe-36 at%Pt alloys were cast in pattern molds for dental magnetic attachment keepers. The attractive forces of the cast Fe-Pt alloy keepers and magnetic stainless steel keepers to dental Fe(14)Nd(2)B magnets (MAGFIT and HICOREX) were measured and statistically evaluated. The saturation magnetization of each Fe-Pt alloy was determined by recording the hysteresis loop using a vibrating sample magnetometer under a magnetic field of 1.6 MA/m. RESULTS: Decreasing the Pt percentage increased the saturation magnetization value and resulted in an increase of the attractive force to each magnet. There was no statistical difference (p>0.05) in attractive force between the Fe-36 at%Pt alloy specimens and the stainless steel keepers for both magnets. A definite correlation between Pt percentage and the value of saturation magnetization was also found (r(2)=-1.000). SIGNIFICANCE: The Fe-Pt alloys with less than Fe-39.5 at%Pt produced high saturation magnetization values and great attractive force to the magnet, and thus, they have the potential to serve as magnetic attachment keepers. Of the Fe-Pt alloys tested, Fe-36 at%Pt seemed to be the best composition for making magnetic attachment keepers.