Electrodeposition of Bulk Nanocrystalline Ni-Fe-P Alloys and Their Mechanical and Soft Magnetic Properties

Abstract

Electrodeposited Ni-Fe alloys are expected to have an improved mechanical strength because of their nanocrystalline structure. However, unsatisfactory grain refinement yields a higher coercivity compared with conventional permalloys, which is undesirable in soft magnetic materials. We report electrodeposited Ni-Fe-P alloys that combine the mechanical properties of nanocrystalline materials with soft magnetism that is achievable in coarse-grained permalloys. Up to 2.0 at% P, the resultant Ni-Fe-P alloys achieved a tensile strength of 2.1 GPa, along with a plastic deformability. The electrodeposited alloys exhibited a saturation magnetic flux density of 1.1 T and a coercivity of 8.4 A/m. Our approach indicates that graine refinement by the P alloying can result in a lower coercivity, according to the law of the grain size and coercivity.