Effect of magnetization state on the corrosion behaviour of NdFeB permanent magnets

The corrosion behaviour of uncoated NdFeB permanent magnets in the non-magnetized and magnetized state was comparatively investigated in H2SO4 solutions by potentiodynamic and potentiostatic polarization experiments. Depth profiles of the corroded surfaces were recorded and an effect of magnetization on the localization of the corrosion attack was identified. The anodic behaviour is discussed on the basis of previously reported results on the corrosion of neodymium and iron and on basis of the magnetic forces acting on the electrochemical system.

► Impact of magnetization state of NdFeB magnets on their corrosion.
► Free corrosion in low concentrated H2SO4: mechanical degradation.
► Anodic polarization: magnetic field reduces current density.
► Magnetic field localizes corrosion attack.
► Pseudo-passive behaviour at high anodic potentials.