Science Daily October 24, 2022
Tetrataenite, an iron-nickel alloy with a particular ordered atomic structure, is one of the most promising material to replace rare earth magnet. It forms over millions of years as a meteorite slowly cools, giving the iron and nickel atoms enough time to order themselves into a particular stacking sequence within the crystalline structure, ultimately resulting in a material with magnetic properties approaching those of rare-earth magnets. The 1960s technique for forming tetrataenite is not suitable for mass production. An international team of researchers (Italy, Austria, UK) found a possible alternative that doesn’t require millions of years of cooling or neutron irradiation. According to the researchers, phosphorus, which is present in meteorites, allows the iron and nickel atoms to move faster, enabling them to form the necessary ordered stacking without waiting for millions of years. By mixing iron, nickel, and phosphorus in the right quantities, they were able to speed up tetrataenite formation by between 11 and 15 orders of magnitude, such that it forms over a few seconds in simple casting. To make tetrataenite they melted the alloy, poured it into a mold. According to the researchers more work is needed to determine whether it will be suitable for high-performance magnets…read more. Open Access TECHNICAL ARTICLEÂ
Composition mapping of an Fe50Ni30P13C7 as-cast 1 mm diameter rod…. Credit: Advanced Science, 2022; 2204315Â