FORMATION MECHANISM OF PROTECTIVE RUST ON WEATHERING STEEL

Corrosion rate of carbon steel and the weathering steel in the marine atmosphere by Qingdao for 3 years was compared,and the distribution of the alloy elements in the rust layer was determined. The result shows that the structure of corrosion rust of weathering steel exposed for 3 years consisted of inner layer and outer layer obviously. The former was compacted and composed of α-FeOOH mainly, and looked dark by the polarized light. However, the latter is of γ-FeOOH and a little FeO, and appeared bright by the polarized light.