How Extrinsic Is the Coercivity in NdFeB Bonded Magnets?

The influence of the densification step, performed by uniaxial pressing at room temperature, on the coercivity μ
₀
H
_c
of NdFeB bonded magnets has been analyzed. The mass density does not play any role on μ
₀
H
_c
of non-cured magnets prepared by the mentioned method. Due to the brittle and intergranular character of the Nd
₂
Fe
₁₄
B-based phase fracture, the nano-sized grains are not affected or the modification is negligible, which maintains μ
₀
H
_c
unchanged. After curing, the intrinsic coercivity of the magnets is reduced as a function of the compaction pressure increase.