Corrosion resistance of T-ZnOw/PDMS-MAO composite coating on the sintered NdFeB magnet

Abstract A zinc oxide whisker/polydimethylsiloxane-micro-arc oxidation (T-ZnOw/PDMS-MAO) composite coating was fabricated via MAO treatment coupled with spraying T-ZnOw/PDMS on sintered NdFeB magnet. The surface morphologies, chemical compositions and corrosion resistance of the composite coating were investigated using SEM, XRD, FT-IR, accelerated immersion test and electrochemical test, respectively. The effect of the composite coating on magnetic properties of NdFeB magnet was also studied. The results show that the composite coating has no significant effect on the magnetic properties of NdFeB magnet. The porous structure of the MAO coating is efficiently sealed by the PDMS molecules and the T-ZnOw/PDMS hybrid coating exhibits excellent superhydrophobicity with a contact angle of 168.67 ± 5.71° and sliding angle of 5.12 ± 2.81°. The T-ZnOw/PDMS-MAO composite coating can significantly enhance the corrosion resistance of the sintered NdFeB magnet.