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Rare earth permanent magnets (Nd-Fe-B) have revolutionized many technologies including automotive, electronics, and biomedical by reducing weight and increasing efficiency. One limitation that has constrained the still wider use of Nd2Fe14B permanent magnets is thermal stability. Alloy modifications of Nd-Fe-B have proven to increase the thermal stability by increasing both room temperature coercivity and Curie temperature, however, at the expense of impairing energy product and remanence. A balanced microstructure and nanoscale thin film coating will offer substantial improvement in thermal stability without such reductions in remanence and energy product. A thin film coating in the nanoscale regime can prevent the nucleation of reverse magnetic domains at the surfaces. The technical approach under investigation consists of traditional alloying with Co to form Nd2Fe10Co4B melt-spun ribbons with a grain size of 20-40 nm and then using a nanosecond pulsed laser to deposit and rapid diffusion anneal Dy2Fe10Co4B into Nd2Fe10Co4B to result in Dy-rich grain boundaries as well as form nanoscale coating of Dy. In this study, a local electrode atom probe microscope is used to obtain three dimensional atom scale characterization of laser deposited Dy2Fe10Co4B thin films (thickness of 100 nm) onto stainless steel needle shaped substrates. Characterization of the film nanostructure as a function of laser processing parameters is carried out to understand the process-structure relationship for the thin film. |