Journal of Magnetism and Magnetic Materials | 2019
Evidence of exchange coupling in τ-MnAlC/FeCo system
Abstract
Abstract The τ -MnAlC/FeCo system has potential to be applied as rare earth-free permanent magnet, due to exchange coupled between hard and soft magnetic phases as alternative for the development of high energy product permanent magnets. In this work the hard-magnetic phase Mn53.3Al45C1.7 ( μ 0Hc\u202f=\u202f0.37\u202fT of coercive force, Mr\u202f=\u202f23.52\u202fAm2/kg of remanent magnetization, Ms\u202f=\u202f52.94\u202fAm2/kg of saturation magnetization and (BH)max\u202f=\u202f3.89\u202fkJ/m3 of maximum energy product) was mixed with the soft magnetic phase Fe65Co35 ( μ 0Hc\u202f=\u202f0.007\u202fT and Ms\u202f=\u202f221.33\u202fAm2/kg) using a solid-state procedure. The magnetic materials were sintered using different ratios of hard and soft magnetic phases: 95:5, 90:10, 85:15 and 80:20; and different sintering temperatures (300, 400, 500 and 600\u202f°C) in order to improve the magnetic properties. The magnetic exchange coupling between MnAlC and FeCo was proved by the hysteresis loop and its corresponding Thamm-Hesse analysis. The best result was obtained for MnAlC/FeCo (95/5\u202fwt%) sintered at 500\u202f°C during 30\u202fmin, for which the magnetic properties were μ 0Hc\u202f=\u202f0.277\u202fT, Ms\u202f=\u202f76.43\u202fAm2/kg and (BH)max\u202f=\u202f5.57\u202fkJ/m3.