DEVELOPMENT OF NEW NANOSIZED SOL GEL COATINGS ON STEEL WITH ENHANCED CORROSION RESISTANCE
Sol gel method is a simple a low cost technique, which gives possibility to deposit coatings with definitely chemical and phase composition at low temperatures. Here we report an application of sol gel method by dip coating technique to prepare a several type of nanosized coatings: (a) one-component coatings such as TiO2 and Nd doped TiO2 (b) two types of bi-component layers, which contain as underlayer SiO2 and upper layer TiO2 or CeO2. The coatings were characterized by XRD, SEM and AFM analyses. The XRD data revealed anatase phase for TiO2 and Nd doped TiO2 coatings. The presence of cubic CeO2 and SiO2 crystallographic phases were proved in SiO2/CeO2 sample. The morphological investigations of the coatings revealed that they have relatively dense surface. The anticorrosion properties were estimated by exposing the samples to the action of salty solution of 3.5% NaCl and was evaluated by their weight losses. Corrosion attack induces insignificant alteration of the surface morphology of both Nd doped TiO2 samples and multilayer barrier coatings. Pits and other significant visible signs of corrosion are not found according to AFM and SEM analyses. The results proved that the investigated bi-component oxide coatings on the base of titania and ceria deposited on SiO2 exhibit better corrosion resistance than the noncoated steel and one component samples. These type of oxide coatings could be perspective for various applications in industry due to their good anticorrosion properties.