Electrochemical behavior of rare-earth magnet alloys in various solutions

Author

Chin, T.S. ; chang, R.T. ; Tsai, W.T. ; Hung, M.P.

Author_Institution

Dept. of Mater. Eng., Nat. Cheng Kung Univ., Tainan, Taiwan

Volume

24

Issue

2

fYear

1988

fDate

3/1/1988 12:00:00 AM

Firstpage

1927

Lastpage

1929

Abstract

Electrochemical behavior of rare earth magnet alloys SmCo₅, Sm₂TM₁₇, and Nd-Fe-B in various aqueous solutions was investigated. Although they are very reactive both in air and aqueous solutions, passivation is still possible in orthophosphoric acid. The ability to passivate, the passivated current density, and breakdown voltage of the passivated films were found to be related to the content of rare earth element, single- or multiple-phase state, and iron content of the alloys, respectively. Galvanic current density of the coupled pairs between one of the magnet alloys and one of the biomedical alloys (amalgam, Co-Cr, and Ni-Cr alloys) was found to be within 3-15 mu A/cm² in synthetic saliva. However a large value of 25 mu A/cm² between a Nd-Fe-B magnet and a Ni-Cr alloy was observed.

Keywords

boron alloys; cobalt alloys; electric breakdown of solids; electrochemistry; iron alloys; neodymium alloys; passivation; permanent magnets; rare earth alloys; samarium alloys; Co-Cr; Nd-Fe-B; Ni-Cr; SmCo₅; aqueous solutions; biomedical alloys; breakdown voltage; electrochemical behaviour; galvanic current density; multiple-phase state; orthophosphoric acid; passivated current density; passivated films; passivation; rare-earth magnet alloys; synthetic saliva; Aluminum alloys; Biomedical measurements; Cobalt alloys; Current density; Current measurement; Galvanizing; Iron alloys; Magnetic materials; Nickel alloys; Voltage;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/20.11648

Filename

11648