Design and Fabrication of Sintered Nd-Fe-B Magnets With a Low Temperature Coefficient of Intrinsic Coercivity

To decrease the temperature coefficients of sintered Nd-Fe-B magnets, the influencing factors on temperature coefficients, especially the reversible temperature coefficient beta of intrinsic coercivity H(cj), were analyzed. The results showed that the absolute value of beta decreased with increasing H(cj) and also the ratio of microstructure parameter c to N(eff), indicating that the increase of magnetocrystalline anisotropy field H(A) and c/N(eff) can effectively decrease the absolute value of beta. On the basis of this analysis, a sintered Nd-Fe-B magnet with a low temperature coefficient of H(cj) was fabricated through composition design, and the value of beta was only -0.385 %/degrees C in the temperature interval of 20-150 degrees C.