Highly dispersive α″-Fe16N2 particle synthesis using hydroxyapatite coating

•Highly dispersed α″-Fe16N2 NPs were synthesized using hydroxyapatite (HAp).•HAp coating was stable chemically and thermally during gas reaction of α″-Fe16N2 synthesis.•The magnetic property of the resultant Fe16N2 NPs are Ms of 170 emu/g and HC of 2450 Oe.

Alpha″-Fe16N2 nanoparticles (NPs) with high magnetic crystalline anisotropy are useful for practical applications such as recording media. However, due to their strongly aggregated and/or sintered form, which occurs during synthesis, the utilization of the NPs has been limited thus far. Here, we report a method for synthesizing highly dispersive α″-Fe16N2 NPs using hydroxyapatite (HAp). The chemically and thermally stable structure of the HAp coating results in the isolation of individual NPs, such that sintering is prevented during synthesis. Additionally, the acicular shape of the HAp crystal did not hinder gas diffusion during the gas reaction. Finally, HAp can be removed by a chelating agent without deteriorating the magnetic properties, resulting in highly dispersive α″-Fe16N2 NPs.

Graphical abstractSynthesis process of highly dispersive α″-Fe16N2 particles using hydroxyapatite coating and SEM images of nanoparticles.Figure optionsDownload full-size imageDownload as PowerPoint slide