Rapid solidification of Nd1+XFe11Ti compounds: Phase formation and magnetic properties. (November 2019)

• Record Type: Journal Article
• Authors: Maccari, F.; Schäfer, L.; Radulov, I.; Diop, L.V.B.; Ener, S.; Bruder, E.; Skokov, K.; Gutfleisch, O.
• Is Part Of: Acta materialia. Volume 180(2019)
• Page Start: 15
• Page End: 23
• Publication Date: 2019-11
• Subjects: ThMn12 structure -- NdFe11Ti -- Magnetic properties -- Twin boundaries; Materials -- Periodicals; Materials science -- Periodicals; Materials -- Mechanical properties -- Periodicals; Metallurgy -- Periodicals; Chemistry, Inorganic -- Periodicals; 620.112
• DOI: 10.1016/j.actamat.2019.08.057
• Languages: English
• ISSNs: 1359-6454

Abstract

Abstract: The effects of compositional variations and different annealing regimes in Nd(Fe, Ti)12 alloys were studied in terms of phase formation and magnetic properties analysis. Ndx Fe11 Ti (x = 1.05, 1.10, 1.15, 1.20) alloys were produced by rapid solidification through suction casting technique. The effect of Nd content and post annealing were investigated in the temperature range of 700–1200 °C. Single 1:12 phase samples were obtained at temperatures between 1150 and 1200 °C for compositions with Nd concentration of 1.15 and 1.20. Intrinsic magnetic properties and magnetization reversal were studied for 1:12 single phase samples, revealing uniaxial anisotropy with anisotropy field ( H A ) of 1.08T and saturation magnetization of 137 Am 2 kg −1 at room temperature. In addition, the demagnetization mechanism in bulk polycrystalline samples was analyzed by means of Kerr microscopy under applied magnetic fields. Magnetization reversal process starts at the twin boundary, which acts as a nucleation center for the reversal domain, and coupling between adjacent grains is also observed. These may be part of the reasons for the observed low coercivity in the NdFe11 Ti systems. The findings of the present study leads to a better understanding of the relation between magnetic properties and microstructure, and can open new strategies to obtain coercivity in this 1:12 phase system and, possibly, in the corresponding nitride. Graphical abstract: Image 1