Green synthesis of silica nanoparticles and its corrosion resistance behavior on mild steel

Abstract

In the past few years, several studies have been made in the preparation of silica from natural resources (rice husk) and its effects on purification and characterization studies. The waste materials generally have been disposed off without any environmental pollution but indeed the waste materials itself are recognized as a source of silica. In the present investigation, rice husk is subjected to sintering at 900 °C for 7 h. The sintered sample was then treated with 1 M NaOH to form sodium silicate. Filially, the gel was taken and reacted with 6 M H2SO4 to precipitate silica. The precipitated samples were characterized by XRD and the morphology was studied by AFM analysis. The silica coatings represent a promising approach for the development of a corrosion protective surface because of its chemical inertness, barrier properties. Silica coatings were developed on mild steel substrates by dip coating and its electrochemical behavior has been evaluated by the Tafel extrapolation method and EIS analysis using 3.5% sodium chloride solution as electrolytes. From the results, it was found that the silica coatings produced by dip coatings has excellent corrosion resistance behavior than the uncoated.