Corrosion Resistance of Magneto-Optical Recording Media

The effects of adding Ti to TbFe and TbCoFe films with and without protective layers were studied. The addition of Ti improved the corrosion resistance of the films more effectively than an SiO₂ protective layer. 10 percent Ti tripled the corrosion resistance of TbFe films and doubled that of TbCoFe films. Pit formation during aging and immersion in brine was eliminated almost completely by the addition of 5 percent Ti, which also increased the Kerr rotation angle (θ_K) slightly in TbFe and TbCoFe films. 10 percent Ti lowered θ_K somewhat while improving the corrosion resistance.