Creating strong permanent magnets without using so-called rare earth elements is an ongoing topic of research. An interesting contestant here are iron nitride magnets (α”-Fe16N2), which have the potential to create permanents magnets on-par with with neodymium (Nd2Fe14B) magnets. The challenging aspect with Fe-N magnets is their manufacturing, with recently [Ben Krasnow] giving it a shot over at the [Applied Science] YouTube channel following the method in a 2016 scientific paper by [Yanfeng Jiang] et al. in Advanced Engineering Materials.
This approach uses a ball mill (like [Ben]’s planetary version) with ammonium nitrate (NH4NO3) as the nitrogen source along with iron. After many hours of milling a significant part of the material is expected to have taken on the α”-Fe16N2 phase, after which shock compaction is applied to create a bulk magnet. After the ball mill grinding, [Ben] used a kiln at 200°C for a day to fix the desired phase. Instead of shock compaction, casting in epoxy was used as alternative.
Continue reading “Iron Nitride Permanent Magnets Made With DIY Ball Mill”
