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 Fe14Nd2B 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 (r2=−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.