Effects of Co, Zr Additions on the Magnetic Properties of Nanocomposite Nd₂Fe₁₄B/α-Fe Magnets

Abstract

The effects of the additions of Co, Zr on microstructure and magnetic properties were studied for hot-deformed (HD) nanocomposite Nd11.5Fe81.5-xNb1CoxB6 (x=0, 2, 4, 8) and Nd11.5Fe82.5-xZrxB6 (x=0, 1) magnets, respectively. The remanence of hot-pressed (HP) magnets increased with increasing Co content firstly, but decreased when Co content was more than 2 at. % for HD magnets. Also the intrinsic coercivity (Hci) and maximum energy product ((BH)m) of HD alloys increased firstly, and then decreased with further increasing Co content. The maximum (BH)m of 24 MGOe was obtained at 2 at.% Co addition. Zr addition can improve significantly the c-axis alignment and magnetic properties of HD nanocomposite magnets, and HD Nd11.5Fe81.5Zr1B6 magnet with 1.5 wt.% Zn addition showed enhanced properties with Hci of 7100 Oe and remanent magnetization (Mr) of 1.06 T. The alloys have the structure of plate-like grains, but there are still many coarse grains, which may result from the un-uniform composition in the alloy.

The Effect of Alloying on the Fractional Composition, Shape and Grain Size Distribution of the Structure Alloy GAP the Fe-Nd-B System

“…The magnetic materials of alloys of the iron-neodymium-boron system certainly have very high practical significance, however, the theory of ferromagnetism of borides in stoichiometry TM14REM2B does not have a complete accurate quantitative model, it requires verification, refinement and further development. Alloying the alloy with transition and rare-earth metals and boron group metals affects the crystallographic parameters of the structure, changes the electronic structure of the alloy, and ensures the formation of high-level magnetic properties [1][2][3]. The magnetic properties of the material and products from such an alloy are sensitive to the type of grain structure and grain size [4].…”