Materials Science & Engineering
LI Zhijie, ZHENG Yangyang, LI Renjun, BAI Bing, ZHANG Hongwei, ZHAO Danna
In order to improve the magnetic properties and corrosion resistance of sintered NdFeB, grain boundary doped Al65Cu20Fe15 nanoparticles were used to prepare sintered NdFeB magnets with high performances, and an electrochemical workstation was used to investigate the corrosion behaviour of doped magnets in 3.5%NaCl solution. The results show that the doping of Al65Cu20Fe15 nanoparticles can form a low melting point phase in the magnet, improve the wettability between the grain boundary and the main phase, inhibit the magnetic coupling among the hard magnetic phase, and enhance the magnetic properties of the magnets. When the mass fraction of Al65Cu20Fe15 nanoparticles is 0.4%, the magnet has the highest magnetic force with the coercivity of 978.1 kA/m, the maximum magnetic energy product of 270.3 kJ/m3 and the remanence of 1.208 T. Compared with the undoped magnet, the corrosion potential of magnet doped with 0.4% Al65Cu20Fe15 nanoparticles increases from -0.881 6 V to -0.704 0 V, while the corrosion current density decreases from 78.292 9 μA/cm2 to 33.222 9 μA/cm2, and the arc radius of high frequency capacitive reactance is much larger than that of the undoped magnet. Therefore, the corrosion resistance of the magnet can be effectively improved.