Enhancement of corrosion protection of stainless steel by nanostructured sol-gel ZrO2 films

Bačić, Ivana (2016) Enhancement of corrosion protection of stainless steel by nanostructured sol-gel ZrO2 films. Doctoral thesis, Faculty of Science > Department of Chemistry.

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Abstract

In this thesis nanostructured films of zirconia stabilized with yttria were prepared by sol-gel method and deposited on the austenitic stainless steel AISI 316L (X2CrNiMo17-2-2) surface by dip coating method. Process parameters optimisation for YSZ films was the aim of the study. Influence of the amount of crystal structure stabiliser, number of layers, withdrawal speed, soaking time, temperature and atmosphere of thermal processing were determined. For the characterization of sol-gel ZrO2 films and its powders following analytical techniques were used: powder X-ray diffraction (PXRD), Fourier transform infrared (FTIR) and Raman spectroscopies, differential thermal/thermogravimetric analysis (DTA/TG), differential scanning calorimetry/thermogravimetric analysis (DSC/TG), evolved gas analysis-mass spectrometry (EGA–MS), glow-discharge optical emission spectrometry (GD–OES), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDS), atomic force microscopy (AFM). Electrochemical corrosion behaviour of the sol-gel ZrO2 films coated and uncoated stainless steel substrates was evaluated by electrochemical tests such as Tafel extrapolation and electrochemical impedance spectroscopy (EIS) in simulated marine environment (3.5 wt.% aqueous NaCl solution). Electrochemical tests confirmed that protection longevity of nanostructure sol-gel ZrO2 film, especially 3 layered films, thermally processed at 400 °C in vacuum, significantly increased corrosion stability of stainless steel in 3.5 wt.% NaCl solution.

Item Type: Thesis (Doctoral thesis)
Keywords: corrosion, electrochemical techniques, sol-gel, stainless steel, thermal processing, vacuum, ZrO2 thin film
Supervisor: Ćurković, Lidija and Otmačić Ćurković, Helena
Date: 2016
Number of Pages: 217
Subjects: NATURAL SCIENCES > Chemistry
Divisions: Faculty of Science > Department of Chemistry
Depositing User: Branka Maravic
Date Deposited: 12 Jan 2017 11:23
Last Modified: 12 Jan 2017 11:23
URI: http://digre.pmf.unizg.hr/id/eprint/5413

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