Preparation of Fe/Cr doped SiO 2 thin film on 304 stainless steel substrate originated from corrosion

A Fe/Cr doped SiO₂ thin film which can improve the anticorrosion characteristic of materials was prepared on SUS304 stainless steel substrates by a modified hydrothermal method which constitutes two parts of preparation process. The corrosion of stainless steel stimulated by aqueous Lithium bromide solution and the dissolution of silica from Na–Ca glass simultaneously. And then a Fe/Cr doped SiO₂ thin film is coated onto the substrate. The Fe/Cr doped SiO₂ film was characterised by scanning electronic micrographs, X-ray diffraction, X-ray photoelectron spectroscopy and Electron probe X-ray microanalyser. Results showed that the corrosion products M^X+, M(OH)^x+ (M: metal) and the silica reticular are combined to form a Fe/Cr doped SiO₂ thin film. Furthermore, a chemical bond formed between silicon reticular and metal ions to improve the compactness and the adhesive property of the film. The anticorrosion characteristics of the film were measured by the methods of weight loss and electrochemical potentiodynamic polarisation, indicating that the Fe/Cr doped SiO₂ thin film can improve the anticorrosion performance of stainless steels effectively.