Thermomagnetic Analysis of Nanocrystalline Nd<SUB>4.5</SUB>Fe<SUB>77</SUB>B<SUB>18.5</SUB> Alloy

Abstract

Changes in the phase composition and crystallite size of a rapid quenched Nd 4:5 Fe 77 B 18:5 alloy, caused by thermomagnetic measurements (TM) have been studied using XRD methods of phase analysis, crystallite size and lattice microstrain determination. Structural changes in regard to optimal magnetic state were additionally analyzed by TEM. Magnetic properties in optimal magnetic state and after TM were observed using room temperature SQUID measurements. The obtained experimental results suggest the Fe 3 B/Nd 2 Fe 14 B and partly -Fe nanocomposite structure of the alloy in the optimized magnetic state, with mean crystallite size (< 30 nm). After TM, an increased amount of -Fe phase, presence of different oxide and Fe-B phases as well as growth of crystallites are found to be the main reasons for the observed quality loss of hard magnetic properties.

Nd-rich Effects on Structural and MagneticProperties of Nd&lt;sub&gt;2&lt;/sub&gt;Fe&lt;sub&gt;14&lt;/sub&gt;B Magnets

“…The methods of the preparation also have been developed time to time. The newest nanocrystalline magnetic materials based on Nd-Fe-B alloys prepared by the rapid quenching of the liquid, known as exchange-coupled nanocrystalline composite hard magnetic materials [2,3,4,5,15].…”