Nd取代对Pr-Nd-Fe-B烧结磁体耐腐蚀性的影响

以HAST加速寿命试验后磁体失重，以及在不同腐蚀介质中磁体动电位极化曲线为表征，研究稀土元素Nd取代Pr对烧结Pr-Nd-Fe-B磁体耐腐蚀性的影响.结果表明:用Nd完全取代Pr后，磁体失重减小，室温下在0.1 mol/L HCl溶液、3.0 % NaOH溶液、3.5 % NaCl溶液中腐蚀电位不同程度地正移，表明磁体耐腐蚀性得到改善.通过场发射扫描电子显微镜观察HAST试验后磁体的微观组织形貌发现，Nd取代Pr后，晶界分布变得更加连续、清晰，且晶界交隅处的富稀土相含量减少，从而延缓了晶界腐蚀速率，使磁体的总体耐腐蚀性得到提升. 

Effect of Nd Substitution for sintered Pr-Nd-Fe-B magnet corrosion resistance

Effects of Nd substitution for sintered Pr-Nd-Fe-B magnets corrosion resistance were investigated, via mass loss of the magnets by HAST, and potentiodynamic polarization curves under different corrosive mediums. The result shows that the mass loss reduced, and the corrosion potential moved positively to different extent within the condition of 0.1 mol/L HCl, 3.0 % NaOH and 3.5 % NaCl aqueous solution, after the rare-earth element Pr of the sintered Pr-Nd-Fe-B magnet completely been substituted, which indicates the better resistance against electrochemical corrosion. The microstructure of the magnet using Nd by SEM in comparison with the(Pr-Nd) one suggests that the grain boundaries becomes more clear and continuous, and the Nd-rich phase at triple junctions is reduced. Through which the corrosion rate of the grain boundaries is slowed down, and as is effective to the corrosion resistance.