08380 Galvanic Behavior of Aluminized Steel Type 2 with Coating Breaks in Waters of Varying Scaling Tendencies

Available for download

Product Number: 51300-08380-SG

ISBN: 08380 2008 CP

Author: Leonardo Caseres and Alberto Sagüé

Publication Date: 2008

Member Price: $0.00

Non Member Price: $20.00

Price: $20.00

Qty:

Aluminized steel Type 2 is produced as a carbon steel sheet hot dip coated on both sides with commercially pure aluminum, forming a layered Al/Al-Fe coating that provides corrosion protection through low corrosion rates of the sound outer aluminum when it is passive. However, if the aluminized coating is partially disrupted exposing the underlying steel, accelerated damage by galvanic corrosion of the aluminized coating and/or the exposed steel may take place. To examine this condition, the impedance behavior of aluminized steel Type 2 with coating breaks of various sizes was studied in waters of controlled varying scaling tendencies containing different amounts of Ca+2, HCO3-, and Cl- ions at room temperature. Initial findings show accelerated corrosion at the exposed steel in mild solutions early in the test, indicative of poor galvanic protection by the coating. However, enhanced galvanic protection by the surrounding aluminized coating was noted later on in the test. Impedance measurements confirmed that corrosion of the aluminized coating was in progress then, resulting in larger protective currents.