Development of TiO2/Nb2O5 Films and Evaluation of Corrosion Prevention in AISI 304

• Published in: Steel research international Vol. 95; no. 6
• Main Authors: Santos, Brenda Ghiane Pena, Machado, Anelise Andrade, Dias, Mércia Silva, Silva, Tiago Almeida, Neto, Almir da Silva, Denadai, Ângelo, Oliveira, Fernando Castro de
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 01.06.2024
• Subjects: AISI 304; Anatase; Charge transfer; Corrosion; Corrosion currents; Corrosion prevention; Corrosion rate; Corrosion resistance; Discontinuity; Electrochemical impedance spectroscopy; Electrode polarization; Heat treatment; Immersion coating; Niobium oxides; polarization curves; Sol-gel processes; sol–gel; Thin films; titanium and niobium films; Titanium dioxide
• ISSN: 1611-3683; 1869-344X
• DOI: 10.1002/srin.202300423

The combination of TiO2 and Nb2O5 in thin films has proven promising for preventing the corrosion of AISI 304. The thin films are developed using sol–gel and dip‐coating techniques, followed by heat treatment. Morphological and X‐ray diffraction analyses indicate a predominant anatase phase in TiO2, and isomorphic substitution of up to 20% Nb occurs in the thin‐film composition. Phase segregation above 30% is observed. Electrochemical tests are conducted in a 2 mol L−1 HCl solution. Scanning electron microscopy reveals satisfactory thin film deposition on AISI 304 but shows the presence of regions with discontinuities. Polarization curves show a corrosion current of 128.72 μA for pure AISI 304, an average corrosion current of 0.34 μA for thin films, and an average of 6.44 μA for films with discontinuities. This significant reduction in current demonstrates the efficiency of the corrosion protection of the film at the studied concentrations because of the high corrosion inhibition percentages. Electrochemical impedance spectroscopy results suggest a high charge transfer resistance, indicating a lower corrosion rate in xTiO2 the yNb2O5 films compared to uncoated AISI 304. Films are prepared using the sol‐gel technique, dip‐coating deposition with controlled immersion speed, and heat treatment curve. Variations occur in the concentrations of alloys and niobium. X‐ray diffraction analysis identifies an anatase phase. Current resistance significantly decreases for American Iron and Steel Institute (AISI) 304 with deposited film compared to AISI without film. Other electrochemical parameters corroborate the positive performance in corrosion resistance.