The properties of oxide and water films formed during the atmospheric exposure of iron and low alloy steels

The primary oxide and water films on iron and low alloy steels have been characterized using ellipsometry. Ellipsometry data obtained during stepwise water film formation are consistent with a model of two layers on iron where the water layer grows and the primary oxide layer remains unchanged in thickness. The thickness of water films on primary oxide layers falls within 0–4 nm and depends significantly on atmospheric conditions. The growth properties of water films are influenced by SO2. Stepwise drying studies give results which indicate modification of the primary oxide-water film interfaces.