A Study on Corrosion and Passivation of Cobalt

금속 코발트의 부식과 부동화에 관한 연구

  • 천정균 (서강대학교 이공대학 화학과) ;
  • 백운기 (서강대학교 이공대학 화학과)
  • Published : 1974.12.30

Abstract

Corrosion and passivation of metallic cobalt was studied by means of electrochemical experiments including potentiostatic and galvanostatic measurements and cyclic voltammograms. The mechanisms of active dissolution and passivation of cobalt at the metal/borate buffer solution interface are deduced from the Tafel slope, pH dependence of the Flade potential, and dissolution kinetic data. Hydroxyl group adsorbed on cobalt surface seems to participate in surface oxidation and formation of the passive layer. The growth kinetic data as measured by the current density suggests a mechanism in which the growth of the passive layer is determined by field-assisted transport of ions through the layer. Thickness of the passive layer was estimated by coulometry to be about 10${\AA}$ at the lowest passive potential and to grow gradually with anodic potential to about 20${\AA}$.

Keywords

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