The properties of aluminium coating on sintered NdFeB by DC magnetron sputtering

Pure aluminium coating was deposited on sintered NdFeB magnets by direct current (DC) magnetron sputtering to improve the corrosion resistance. The corrosion behaviour of sintered NdFeB coated with aluminium was characterized by potentiodynamic polarization measurement. The adhesive strength between the aluminium coating and the sintered NdFeB was characterised by vertical tensile test and high-low temperature shock test. The influence of the coating on the magnetic properties of the sintered NdFeB was also characterised. It was found that the aluminium coating can improve the corrosion resistance of the sintered NdFeB evidently. The aluminium coating was well adhesive with the substrate and did not deteriorate the magnetic properties of the sintered NdFeB magnets. These two characters may overcome the disadvantages of NiCuNi coating which is usually electroplated on NdFeB in industry. (c) 2010 Elsevier Ltd. All rights reserved.