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First direct bulk synthesis of rare-earth-free hard magnet tetrataenite
- scythe 4y ago>Despite many attempts with diverse approaches, bulk synthesis of tetrataenite has not been reported. Here it is shown that with appropriate alloy compositions, bulk synthesis of tetrataenite is possible, even in conventional casting at cooling rates 11‒15 orders of magnitude higher than in meteorites Tetrataenite, an alloy of iron and nickel, is a hard magnetic material with a magnetic energy product comparable to neodymium iron boride, is stable at room temperature but not at high temperature and historically believed to only form through extremely slow (>10^6 years) crystal relaxation in iron-nickel meteorites. Nanopowder tetrataenite has previously been synthesized by various deposition, decomposition and milling processes, but these powders are not easily converted into macroscopic magnets, and generally produced in small amounts. In this study, an intermetallic iron-nickel-phosphorus-carbon eutectic is shown to precipitate bulk tetrataenite as dendritic crystals upon annealing at industrially useful rates, demonstrating a potentially highly significant pathway for the production of permanent magnets from common materials.
- MaxikCZ 4y agoWait so they just mixed the metals (mostly iron and nickel) with a little phosphorus, warmed and let it cool and got really strong permanent magnet, stable to around 500(or 300)°C, while hinting no obstacles for industrial scale production? That's huge!
- scythe 4y agoYes, it has to be replicated, but if confirmed, this could make strong permanent magnets a lot cheaper. Potentially geopolitically significant, even.
- simne 4y agoThey may not be cheaper. Here important, strong permanent magnets will become available without making deal with non-friendly countries.