Corrosion Resistance of TbFeCo ‐  M  Magneto‐optical Films

Abstract

The corrosion mechanism of magneto‐optical media and the influence of the addition of a fourth element on corrosion resistance has been studied. The corrosion is classified into three types, i.e., wet corrosion, dry corrosion, and pitting corrosion. Fourth elements that are effective in preventing wet corrosion are Ti, Ta, Nb, and Cr. Those useful for dry corrosion are Nb, Ta, Cr, Pd, and Pt. The ones effective for pitting corrosion are Nb, Ti, Ta, Cr, Pt, and Pd. A passive layer forms on the surface of the film when an effective fourth element is added. Ti, Ta, Nb, and Cr are thus effective in preventing all three types of corrosion.