Corrosion of NdFeB permanent magnet materials
作者:
G. W. Warren,
G. Gao,
Q. Li,
期刊:
Journal of Applied Physics
(AIP Available online 1991)
卷期:
Volume 70,
issue 10
页码: 6609-6611
ISSN:0021-8979
年代: 1991
DOI:10.1063/1.349873
出版商: AIP
数据来源: AIP
摘要:
NdFeB is an important class of new magnetic materials, however corrosion resistance is a serious concern and literature on the electrochemical behavior of NdFeB is scarce. This paper reports the results of an electrochemical investigation of the corrosion behavior of sintered NdFeB magnets obtained from three manufacturers. Linear polarization (cyclic voltammetry) experiments were conducted in aqueous solutions ranging inpH from 0.7 to 13.5. A limited degree of passivation was observed in all solutions which is believed to be due to the formation of a complex Fe‐Nd oxide and/or hydroxide film. The presence of a small amount of chloride ion, 10 to 100 ppm, shows only a slight effect, but higher concentrations (1000 ppm) cause a total breakdown in passivity and a dramatic increase in anodic current. The cathodic potential sweep shows an abrupt and unusual oxidation process, giving rise to an oxidation peak not commonly seen. This peak may result from dissolution of the film or preferential attack of intergranular phases.
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