Corrosion Inhibition of 304 Stainless Steel, Copper and Nickel Metals Using Mesoporous Silicate (MCM- 41) and 2, 5- Distyrylpyrazine Photopolymer M. B. Zakaria a , M. A. Elmorsi a , and E. M. Ebeid a, b a Department of Chemistry, Faculty of Science, Tanta University, Tanta, Egypt b Misr University for Science and Technology (MUST), 6 th of October City, Egypt Mesoporous silicate (MCM-41) and 2, 5-distyrylpyrazine photo- polymer (poly-DSP) were used as corrosion protective coatings for 304 stainless steel, copper and nickel metals. Films on metal surfaces were prepared by dip-coating and vapor deposition (CVD, PVD) methods. Poly-DSP thin films formed by vapor deposition are expected to be incorporated through pores and micro-cracks of SiO 2 thin film resulting in extra corrosion protection upon photo polymerization. MCM-41 thin films were characterized by x-ray diffraction (XRD), infrared (IR), BET and electron microscopy (SEM, TEM) techniques. Corrosion protection was studied in 2M HCl aqueous solutions using weight loss and potentiodynamic polarization techniques. The temperature effect on corrosion rates was also studied and the thermodynamic activation parameters of the corrosion reaction were determined. Different corrosion parameters were evaluated including, corrosion current density, corrosion potential, corrosion rate and Tafel constants. The calculated percentage of inhibition efficiencies of the coated electrodes reaches ca 93% in some cases. Introduction A general method to enhance corrosion resistance is to apply protective coatings. The modification of the chemical composition of the coatings can also permit the introduction of other desired chemical and physical properties, such as mechanical strength and hydrophobicity. Various organic coatings have been studied for corrosion protection (1- 3). Various oxide coatings obtained by sol-gel processing have been studied extensively for corrosion protection of stainless steel (4-8). In spite of all advantages of sol-gel processing, sol-gel coatings suffer from several drawbacks. Specifically, the high annealing or sintering temperatures (>800 0 C) required to achieve a dense microstructure could possibly introduce cracks and/or delamination within the sol-gel coatings (9-12). One viable approach to dense sol-gel derived coatings without post- deposition annealing at elevated temperature is to synthesize organic-inorganic hybrid coatings. Relatively dense hybrid coatings have been developed for applications, including wear resistance (13, 14) and corrosion protection (15-17). Two common methods for preparing coatings on metal surfaces are gaseous, including physical vapor deposition (PVD) and chemical vapor deposition (CVD) methods (18, 19), and liquid phase (20, 21) methods. Most of the ceramic coatings are formed by sol-gel method which requires considerably less equipment and can be amenable to any accessories in a large and complex shape, and is applicable to substrates that cannot withstand high temperatures (22). However, the coatings fabricated by sol-gel process encounter problems of existing pores and cracks ECS Transactions, 33 (16) 227-243 (2011) 10.1149/1.3553173 ©The Electrochemical Society 227 Downloaded 25 Aug 2011 to 144.213.253.16. Redistribution subject to ECS license or copyright; see http://www.ecsdl.org/terms_use.jsp