Properties of a rare earth free L1(0)-FeNi hard magnet developed through annealing of FeNiPC amorphous ribbons

Abstract

The rare-earth-free hard magnetic L1(0)-FeNi phase found in cosmic meteorites demonstrates potential as a next-generation permanent magnet. However, it is very difficult to artificially produce the L1(0)-FeNi phase due to the low atomic diffusion coefficients of Fe and Ni near the order-disorder transition temperature (similar to 320 degrees C). Therefore, FeNiPC amorphous alloy systems exhibiting crystallization temperature (T-x) near the transition temperature were investigated. The amorphous alloys were annealed at T-x, resulting in high atomic diffusion. The structural and microstructural characterizations of annealed ribbons revealed the formation of L1(0) -FeNi phase through observation of the superlattice peak. The magnetic property, such as coercivity (H-c), also indicated the formation of L1(0)-FeNi phase, because the maximum H-c value is 641 Oe after the annealing process.