Properties of a rare earth free L10-FeNi hard magnet developed through annealing of FeNiPC amorphous ribbons

Abstract

The rare-earth-free hard magnetic L10-FeNi phase found in cosmic meteorites demonstrates potential as a next-generation permanent magnet. However, it is very difficult to artificially produce the L10-FeNi phase due to the low atomic diffusion coefficients of Fe and Ni near the order-disorder transition temperature (∼320 °C). Therefore, FeNiPC amorphous alloy systems exhibiting crystallization temperature (Tx) near the transition temperature were investigated. The amorphous alloys were annealed at Tx, resulting in high atomic diffusion. The structural and microstructural characterizations of annealed ribbons revealed the formation of L10-FeNi phase through observation of the superlattice peak. The magnetic property, such as coercivity (Hc), also indicated the formation of L10-FeNi phase, because the maximum Hc value is 641 Oe after the annealing process.