Facile and fast synthesis of highly ordered L10-FeNi nanoparticles

Abstract

The chemically ordered L10-FeNi alloy is a promising candidate for next generation rare-earth-free permanent magnets, which can revolutionize the high-performance magnets market currently dominated by Nd-Fe-B. Despite many efforts, the experimental results fall short of theoretical predictions, and current approaches are not suitable for industrial implementation. In this work, we propose an innovative and efficient synthesis method that exploits the natural order of a crystalline Ni/Fe complex, which closely mimics the atomic organization in the L10 structure, to drive the formation of the ordered phase. By low-temperature reduction of the complex salt, carbon coated aggregates of FeNi alloy nanoparticles (20 – 120 nm) with a >55% of L10 phase, high coercivity (up to 65 mT) and large saturation magnetization (∼ 140 Am2/kg) were obtained. The results pave the way for the development of a novel and sustainable route to produce high-anisotropy FeNi nanoparticles of potential interest for next generation critical-element-free permanent magnets.