Khaled HABIB and Fathi AL-SABTI

Materials Application Department, KISR, P.O. Box 24885 SAFAT 13109 Kuwait

(Received August 12, 1996; Accepted December 20, 1996)

In a previous study a mathematical model relating surface and bulk behaviors of metals in aqueous solution was developed. The model was established based on principles of holographic interferometry for measuring microsurface dissolution, i.e., mass loss, and on those of electrochemistry for measuring the bulk electronic current, i.e., corrosion current. In the present work, an interferometric sensor was built based on the above model, and the corrosion current density of coated copper and brass in seawater were obtained using this sensor. The interferometric sensor was also utilized for the first time to measure the initial stage of the anodization process (oxidation) of aluminium samples in aqueous solution. This was carried out chemically in different acid concentrations (3.125-25% H₂SO₄) at room temperature. The sensor was further used for observation of catalytic activities, i.e., pitting corrosion, which occurred subsequent to the anodization of the aluminium samples in aqueous solutions, after an oxide film had been formed.

Key words : holographic interferometry, corrosion, pitting corrosion, brass, copper, aluminium, seawater, sulphuric acid, organic coating, chemical anodization, Al₂O₃ oxide film