INFLUENCE OF DY CONTENT ON AQUEOUS CORROS ION OF TBDYFECO MAGNETOOPTICAL RECORDING FILMS

Citation
N. Akao et al., INFLUENCE OF DY CONTENT ON AQUEOUS CORROS ION OF TBDYFECO MAGNETOOPTICAL RECORDING FILMS, Nippon Kinzoku Gakkaishi, 58(3), 1994, pp. 309-317
Citations number
14
Categorie Soggetti
Metallurgy & Mining
Journal title
ISSN journal
00214876
Volume
58
Issue
3
Year of publication
1994
Pages
309 - 317
Database
ISI
SICI code
0021-4876(1994)58:3<309:IODCOA>2.0.ZU;2-T
Abstract
The influence of Dy content on the corrosion resistance of sputter-dep osited TdDyFeCo alloy films for magneto-optical recording media was in vestigated by means of immersion corrosion tests and electrochemical p olarization measurements. Surface films on the alloy were analyzed by X-ray photoelectron spectroscopy (XPS) after the immersion corrosion t ests. As reference specimens, TdDyFeCo alloy tapes prepared by a melt span method were also used. The corrosion mass loss of the alloy films in 0.01 kmol.m-3 NaCl increased with increasing Dy content of the fil ms. The same results were obtained on the alloy tapes. The selective d issolution of Fe and Co to test solutions and the concentration of Tb and Dy in surface films were found after the immersion corrosion tests . Surface films on TbDyFeCo alloys were composed of hydroxides and oxi des of Tb, Dy and Fe. The quantities of hydroxide and oxide of Dy incr eased after the immersion corrosion tests. Anodic current densities in both the active and passive states increased and the pitting potentia l decreased with increasing Dy content of the alloys. This shows the s tability of passive films is deteriorated by the Dy addition to the al loy.