电弧离子镀ZrN/TiN涂层对烧结NdFeB的耐腐蚀及磨损性能的影响

Effect of ion plating ZrN/TiN multilayer coating on the corrosion resistance and anti-wear properties of NdFeB magnet

为了提高粉末烧结磁体NdFeB的耐腐蚀性能和耐磨损性能,采用电弧离子镀的方法在其上沉积制备了ZrN/TiN多层涂层。观察涂层的成分与显微组织,分析了涂层对烧结磁体耐腐蚀性能及磨损性能的影响。结果表明:电弧离子镀氮化物多层涂层与烧结磁体生成一过渡层,膜基结合强度高;涂层提高了磁体的耐腐蚀倾向,降低了腐蚀电流,腐蚀速率降低2个数量级;磁体在5%盐水中10h后才出现失重,涂层保护效果明显;磁体表面涂层的硬度15～20GPa,摩擦系数0.5,耐磨损性能提高。

ZrN/TiN multilayer coatings were deposited by ion-plating on NdFeB substrate.The microstructure and composition were investigated by SEM,XRD and EDS.The electrolyte,5% NaCl,was used for potentiodynamic polarization;The hardness and friction coefficient were analyzed.It is found that： there is a transition layer between the ion-plating ZrN/TiN coating and substrate,resulting in good adhension strength.The uncoated NdFeB appears mass loss after 4 hours,while ZrN/TiN-coated NdFeB appears mass loss after 10 hours,and the corrosion potential become positive and corrosion rate decreases by 2 orders of magnitude at the same time,indicating the corrosion rate is lower than that of uncoated NdFeB.The hardness of coating on NdFeB substrate is 15～20GPa,its friction coefficient is 0.5.It could be concluded that ion-plated ZrN/TiN coatings can increase significantly the corrosion resistance and anti-wear ability of NdFeB magnets.