Effect of Nb additions on the irreversible losses of Nd-Fe-B type magnets

While Nd-Fe-B magnets have outstanding magnetic properties at room temperature (1) and below, their usefulness at higher temperatures is limited by three factors: irreversible loss, reversible loss of B
r
and reversible loss of H
ci
. This work examines the beneficial effects of Nb additions to Nd-Fe-B magnets, in a particular to reduce the irreversible loss.