Effects of silicon and aluminum additions on magnetic properties of rapidly quenched Nd-Fe-B permanent magnets

Abstract
The effects of Si and Al on magnetic properties of melt-spun Nd-Fe-B base alloy permanent magnets were studied. The addition of Si to the Nd-Fe-B base alloy improves magnetic properties: it especially increases the maximum energy product (BH)max up to 20 MG Oe, remanence Br over 9 kG, and decreases intrinsic coercive force iHc. The addition of Si also increases Curie temperature and decreases reversible temperature coefficient. The combined addition of Si and Al spreads wheel surface velocity ranges to obtain (BH)max>15 MG Oe and Br>9 kG compared to the addition of Si only. The origin of high performance is discussed.