Corrosion of multilayers used for magnetoresistive head in aqueous solution environment

Mamoru Ishida, Noboru Akao, Nobuyoshi Hara, Katsuhisa Sugimoto, Sigeo Fujii

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

Magnetoresistive heads (MR heads), which utilize the magnetoresistive effect of ferromagnetic films, are consisted of metal multilayer films. The metal multilayers of the MR heads should cause galvanic corrosion in the water environment. The aim of this study is to make clear the corrosion behavior of the metal multilayers used for MR heads. To investigate the corrosion of real MR heads, the corrosion test of simulated MR head samples having the structure of Au/Fe-Mn/Ni-Fe/Ta/Ni-Fe-Cr was performed in 0.1 kmol·m-3 NaCl and 0.1 kmol·m-3 Na2SO4. Corrosion and electrochemical behavior of each metal film was examined in pH 8.45 boric-borate buffer, 0.1 kmol· m-3 NaCl and 0.1 kmol·m-3 Na2SO4. Galvanic current measurement was performed in the same solutions on galvanic couples of Au and Fe-Mn films or Fe-Mn and Ni-Fe films. It has been found that Fe-Mn films do not suffer from corrosion in pH 8.45 boric-borate buffer owing to the formation of passive films. In 0.1 kmol·m-3 NaCl and 0.1 kmol·m-3 Na2SO4, however, the films suffer from serious pitting corrosion. Moreover, couples of Au and Fe-Mn films or those of Ni-Fe and Fe-Mn films cause galvanic corrosion in the same solutions and the corrosion rate increases with increasing area ratio of Au or the Ni-Fe film to the Fe-Mn film.

Original languageEnglish
Pages (from-to)64-70
Number of pages7
JournalNippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals
Volume61
Issue number1
DOIs
Publication statusPublished - 1997

Keywords

  • Aqueous solution environment
  • Corrosion
  • Dynamic porlarization
  • Galvanic couple
  • Immersion test
  • Magnetoresistive head
  • Multilayers

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Metals and Alloys
  • Materials Chemistry

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