Toward Production of Cost Effective Modification of SmCo5 -Type Alloys Suitable for Permanent Magnets (Review Paper)

Abstract

SmCo5 constitutes one of the strongest class of permanent magnets, which exhibit enormous uniaxial magnetocrystalline anisotropy energy and have a high Curie temperature. However, the performance of SmCo5 permanent magnets is hindered by a limited energy product and relatively high supply risk. Sm is a moderately expensive element among its group, and Co is a material more expensive than Fe, making SmCo5 magnets the most expensive class of permanent magnets. Subsequently, the need for new materials, with less content in critical and thus expensive resources, is obvious. A promising path of producing new compounds that meet these requirements is the chemically modification of established materials used in PM towards the reduction of expensive resources, for example reducing Co content with transition metals (like Fe, Ni) or using as substitutes raw rare earth materials with abundance greater than their demand, like Ce and La. Important instrument to achieve these goals are theoretical calculations, like Ab-initio methods, and especially DFT based calculations in predicting the possible stable RE-TM intermetallic compounds and their magnetic properties. This review aims to present the progress of recent years in the production of improved SmCo5 type magnets.