难熔金属替代对烧结NdFeB磁体磁性及腐蚀行为的影响（英文）

Effect of Refractory Metal Substitution on Magnetic Property and Corrosion Behavior of Sintered NdFeB Magnets

采用粉末冶金法制备了Nd24Fe65.5-xRMxB0.97Tb7.0Dy1.1Co1.0Al0.2Cu0.23(RM=Nb,Zr,Ti;x=0.2,0.4,0.6)高性能磁体。高温磁性能测试结果显示,温度低于200℃时,磁体剩磁温度系数(α)得到明显提高;Nb,Ti替代后磁体矫顽力温度系数(β)也得到了较好的改善。PCT实验结果显示,Nb替代后磁体质量损失只有0.07 mg/cm2,耐蚀性显著增强,而Ti替代后磁体的耐蚀性变差;对腐蚀后磁体表面EDX分析得到,当磁体中含有低于0.2%(质量分数)Zr或Ti时,它们将先于Dy被氧化。

Nd24Fe65.5-xRMxB0.97Tb7.0Dy1.1Co1.0Al0.2Cu0.23（RM=Nb, Zr, Ti;x=0.2,0.4,0.6） magnets with high property were prepared by powder metallurgy process. The measurements of high temperature magnetic properties indicate that the value of α（temperature coefficient of remanence of Nb Fe B magnet） is obviously increased when the temperature is below 200 oC, and β（temperature coefficient of coercivity of Nb Fe B magnet） is well improved after iron is substituted by the refractory metal, e.g. in Nb and Ti-substituted magnets. The result of PCT test shows that the mass loss of Nb-substituted magnets is only about 0.07 mg/cm2, which indicates that the corrosion resistance is enhanced greatly in Nb-substituted magnets, but the opposite phenomenon is observed in Ti-substituted magnets. EDX results reveal that Dy could be prevented from oxidation when more than 0.2 wt% Zr or Ti is doped in the magnets.