Abstract Heterogeneous microstructure of multi-main-phase (MMP) Nd-Ce-Y-Fe-B sintered magnet is unraveled to generate local electrode potential discrepancy of intergranular multi-phases and intragrain core-shells, being the origin of peculiar corrosion behaviors relative to conventional Nd-Fe-B. i) For intergranular heterogeneity, the preferential corrosion of active RE-rich phase yields an abnormal enhancement of anti-corrosion performance. ii) For intragrain heterogeneity, local Ce-rich shell and Ce-rich core with lower Volta potentials evolve as preferential sites for pit corrosion, resulting in large cavities and apparent Ce-oxide accumulation. Above findings unlock the close correlation between heterogeneous microstructure and whole-process corrosion behavior of MMP magnets for the first time.

中文翻译：

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具有非均质组织的多主相Nd-Ce-Y-Fe-B永久材料的特殊腐蚀行为

摘要 多主相 (MMP) Nd-Ce-Y-Fe-B 烧结磁体的非均质显微组织被解开，导致晶间多相和晶内核壳的局部电极电位差异，是相对于特殊腐蚀行为的起源。到传统的 Nd-Fe-B。i）对于晶间非均质性，活性富稀土相的优先腐蚀导致抗腐蚀性能的异常增强。ii) 对于晶粒内异质性，局部富 Ce 壳和具有较低 Volta 电位的富 Ce 核演变为凹坑腐蚀的优先位点，导致大空腔和明显的 Ce 氧化物积累。上述发现首次揭示了MMP磁体异质微观结构与全过程腐蚀行为之间的密切相关性。