Corrosion Resistance of TiN/Al2O3 Multilayer Films Deposited on NdFeB Surface by Magnetron Sputtering

TiN/Al2O3 protective film layer was alternately deposited on the surface of sintered Neodymium Iron Boron (NdFeB) permanent magnet by magnetron sputtering technology, and the effect of different cycles on the surface morphology and microstructure of the protective film was studied.At the same time, the protective performance of protective film was explored for the NdFeB permanent magnet in NaCl solution.The results show that the increase in the number of film layers contributes to the continuous improvement of the quality of each film layer, the nucleation rate of the top film increases, the grains are refined, the surface density of the film layer continues to increase, and the stress of defects in the film layer is also easier to be released across the interface.The process of alternately depositing the film layer effectively prevents the appearance of through holes in the film layer, and has a good protection effect on the NdFeB permanent magnet substrate.