Corrosion Inhibition of 304 Stainless Steel by Nano-Sized Ti/Silicone Coatings in an Environment Containing NaCl and Water Vapor at 400–600°C

摘要

The corrosion behavior of 304 stainless steel (SS) and its corrosion inhibition by brushing nano-sized Ti/silicone coatings on its surface in an environment containing a solid NaCl deposit and water vapor at 400–600°C was studied. Results indicated that water vapor or NaCl, especially water vapor plus NaCl accelerated the corrosion of the steel markedly. The corrosion scales of the uncoated steel had a duplex structure at 400–500°C and internal oxidation occurred for the uncoated steel at 600°C in an environment containing NaCl and water vapor. The corrosion of the 304SS was inhibited efficiently by the coatings at 400–500°C, and the coated steel suffered corrosion to some extent and most of the coatings were destroyed at 600°C. X-ray diffraction (XRD) indicated that the corrosion products of the uncoated steel were mainly Fe2O3, Cr2O3, NiO or Na2CrO4, and the coatings consisted mainly of TiO2 and SiO2 after exposure at 400–500°C. The good corrosion resistance of the nano-sized Ti/silicon coatings was attributed to the formation of SiO2, and TiO2 that resulted from the decomposition of the organic components in the coating and fast oxidation of nano-Ti powder respectively during the experiments, TiO2 mixed together with SiO2 and formed a new coating on the steel surface that played an important role in the protection of the steel.