Corrosion rate activation energy of sputtered CoCr perpendicular media

Corrosion rate activation energy ΔE has been evaluated by measuring electrical resistance increase due to corrosion for CoCr (0 ∼ 26 at%Cr) film stripe patterns under exposure to various temperatures and 85% relative humidity. A relation of corrosion layer thickness X to Cr density x, test temperature T and test time t were obtained. The relation was expressed by , where K, γ and C are the coefficient and Boltzmann\´s constant,respectively. ΔE values for CoCr films (0∼ 26 at%Cr) depend upon Cr density and preparation conditions. These values ranged from 0.075 to 0.32 eV. Corrosion characteristics are varied by not only film microstructure, but also to Cr atom distribution in crystalline matrix even for films with same Cr density.