Magnetic hardening mechanism in sintered R–Fe–B permanent magnets

After a short review on temperature dependence of the intrinsic coercivity in sintered Nd–Fe–B-type magnets is given, recent experimental results concerning the coercivity-anisotropy (H_C–H_A) correlation in B-rich Pr–Fe–B and Nd–Fe–B sintered magnets and the influence of the surface conditions of the sintered Nd–Fe–B magnets on the coercivity are reported. The results are interpreted in terms of the μ_oH_c vs cμ_oH_A – NI_s plot, where I_s is the spontaneous magnetization of R₂Fe₁₄B (R = Pr or Nd) and N is the effective demagnetization field coefficient.