Graphene oxide coating for improved corrosion resistance of NdFeB magnets
Electrophoretic deposition (EPD) of graphene oxide (GO) was carried out on Neodymium iron boron (NdFeB) magnets to study its potential as corrosion resistant coating. GO was produced from powder graphite by Hummers method. The GO was obtained by sonicating graphite oxide/water suspension and GO coatings were deposited on NdFeB magnets by making magnets anode in EPD process and by keeping voltage 10 V and time of deposition 1-2 min. GO and GO coating morphology and structure were studied by atomic force microscopy and x-ray diffraction, respectively. Electrophoretically deposited GO coatings on NdFeB were fairly uniform with some porosity. Potentiodynamic polarization and electrochemical impedance spectroscopy were used to study corrosion behavior of the GO coatings. GO coating reduced the corrosion rate of NdFeB by three times than the bare metal. The results show that GO coatings offer excellent corrosion resistant to NdFeB magnets in 3.5 % NaCl solution.
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