Examinando por Autor "Zamora Alfonso, Ligia Edith"
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- PublicaciónSólo datosEvidence of exchange coupling in -MnAlC/FeCo system(Journal of Magnetism and Magnetic Materials, 2019-03-01) Martínez Sánchez, Hugo; Zamora Alfonso, Ligia Edith; Trujillo Hernández, Juan Sebastián; Pérez Alcazar, Germán AntonioThe -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 (0Hc = 0.37 T of coercive force, Mr = 23.52 Am2/kg of remanent magnetization, Ms = 52.94 Am2/kg of saturation magnetization and (BH)max = 3.89 kJ/m3 of maximum energy product) was mixed with the soft magnetic phase Fe65Co35 (0Hc = 0.007 T and Ms = 221.33 Am2/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 °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 wt%) sintered at 500 °C during 30 min, for which the magnetic properties were 0Hc = 0.277 T, Ms = 76.43 Am2/kg and (BH)max = 5.57 kJ/m3.
- PublicaciónSólo datosMechanochemical Synthesis and Nitrogenation of the Nd1.1Fe10CoTi Alloy for Permanent Magnet(Molecules, 2021-06-26) Martínez Sánchez, Hugo; Hadjipanayis, George; Pérez Alcázar, Germán Antonio; Zamora Alfonso, Ligia Edith; Trujillo Hernández, Juan SebastiánIn this work, the mechanochemical synthesis method was used for the first time to produce powders of the nanocrystalline Nd1.1Fe10CoTi compound from Nd2O3, Fe2O3, Co and TiO2. High-energy-milled powders were heat treated at 1000 °C for 10 min to obtain the ThMn12-type structure. Volume fraction of the 1:12 phase was found to be as high as 95.7% with 4.3% of a bcc phase also present. The nitrogenation process of the sample was carried out at 350 °C during 3, 6, 9 and 12 h using a static pressure of 80 kPa of N2. The magnetic properties Mr, µ0Hc, and (BH)max were enhanced after nitrogenation, despite finding some residual nitrogen-free 1:12 phase. The magnetic values of a nitrogenated sample after 3 h were Mr = 75 Am2 kg–1, µ0Hc = 0.500 T and (BH)max = 58 kJ·m–3. Samples were aligned under an applied field of 2 T after washing and were measured in a direction parallel to the applied field. The best value of (BH)max ~ 114 kJ·m–3 was obtained for 3 h and the highest µ0Hc = 0.518 T for 6 h nitrogenation. SEM characterization revealed that the particles have a mean particle size around 360 nm and a rounded shape.
- PublicaciónSólo datosMechanochemical Synthesis and Nitrogenation of the Nd1.1Fe10CoTi Alloy for Permanent Magnet(Molecules, 2021-06-24) Martínez Sánchez, Hugo; Hadjipanayis, George; Pérez Alcázar, Germán Antonio; Zamora Alfonso, Ligia Edith; Trujillo Hernández, Juan SebastiánIn this work, the mechanochemical synthesis method was used for the first time to produce powders of the nanocrystalline Nd1.1Fe10CoTi compound from Nd2O3, Fe2O3, Co and TiO2. High-energy-milled powders were heat treated at 1000 °C for 10 min to obtain the ThMn12-type structure. Volume fraction of the 1:12 phase was found to be as high as 95.7% with 4.3% of a bcc phase also present. The nitrogenation process of the sample was carried out at 350 °C during 3, 6, 9 and 12 h using a static pressure of 80 kPa of N2. The magnetic properties Mr, µ0Hc, and (BH)max were enhanced after nitrogenation, despite finding some residual nitrogen-free 1:12 phase. The magnetic values of a nitrogenated sample after 3 h were Mr = 75 Am2 kg–1, µ0Hc = 0.500 T and (BH)max = 58 kJ·m–3. Samples were aligned under an applied field of 2 T after washing and were measured in a direction parallel to the applied field. The best value of (BH)max ~ 114 kJ·m–3 was obtained for 3 h and the highest µ0Hc = 0.518 T for 6 h nitrogenation. SEM characterization revealed that the particles have a mean particle size around 360 nm and a rounded shape.