Improving corrosion resistance of copper is often associated with the presence of cuprous oxide (Cu2O) films on the surface. Many surface modification techniques such as chemical etching, oxidation, inhibitors, electro deposition and sol-gel could be employed
In the present work a film of Cu2O, which is considered to be protective and strongly adherent to the substrate, is formed. Experimental technique includes etching of copper specimens in ammonia solution, calcination, and then modified in ethanol solution of stearic acid for different times was employed
Etching of copper for 60 h in 10 wt. % ammonia solution exhibits a contact angle of 135˚ but the formed layer, which is CuO, has poor adhesion.
Modifying of etched-calcined copper in 0.1 mol/L ethanol solution of stearic acid for 3 h shows a superhydrophobic film (Cu2O) with a high contact angle of 160˚, good adhesion and lowest corrosion rate. The contact angle was measured at ambient temperature.
The surface morphology and chemical compositions of the samples were investigated with a scanning electron microscopy, EDX and an X-ray diffraction. Electrochemical corrosion behavior was conducted in 3 wt. % NaCl aqueous solution at room temperature. The contact angle was measured using Attension Biolin device (Theta Optical Tensiometers) Also Thickness (using Tooke Inspection Guage OG204 according to ASTM D4138) and adhesion (using X-Cut Tape Adhesion test according to ASTM D3359) of formed films were determined