Taguchi Optimization of TiO2 Thin Film to Defeat Microbiologically Induced Corrosion of Stainless Steel

Although microbiologically induced corrosion (MIC) is well known by design engineers and manufacturers, most current marine devices continue to be impressed by MIC. This phenomenon originates from colonization of anaerobic microorganisms on metal surface, and subsequently increases the corrosion rate. An investigation was made to defeat MIC by means of applying a TiO_2 thin film on metal surface. 316L stainless steel and sol-gel dipping technique were chosen as the base metal and application method, respectively. The depositing variables including PEG adding amount, pH of the sol, calcination temperature (T), and dipping cycles number, were analyze by Taguchi statistical model to determine their influences on response parameters: bactericidal efficiency, current corrosion density (i_corr), crystallinity, crystallite size, and surface roughness (R_a). A parameter termed Aim was defined to comprise all the response parameters. Taguchi Predicted conditions to achieve the highest Aim value. For this aim, PEG content, pH, T, and dipping cycles should be equal to 1 g per 100 mL of sol, 11, 600 °C, and 2 cycles, respectively. These conditions were applied to prepare the optimized sample. Careful evaluation of this sample approved the Taguchi prediction and the highest Aim value was observed.