Dependence Of The Coercivity H-Cj Of High Energy Nd-Fe-B Magnets On The Alignment Coefficient

Sintered Nd-Fe-B near net-shape magnets with a high remanent polarization of 1.47 T, a coercivity H-cJ of 9.6 kA/cm (12 kOe) and a maximum energy density of 420 kJ/m(3) (53 MGOe) are manufactured by rubber isostatic pressing. The optimization of the remanent polarization by an improved alignment process of the powder particles resulted in a decrease of the coercivity by 0.4 kA/cm per % Delta f(rho) for alignment coefficients in the range 96-98%. For alignment coefficients between 98-99% the decrease of the coercivity even amounts to about -1 kA/cm per % Delta f(rho). The temperature coefficients of such magnets amount to -0.11%/K for the remanent polarization and to -0.77%/K for the coercivity in the temperature range 20-100 degreesC.