Effect of deposition regimes on the properties of sol-gel films

The effect of various deposition parameters on the properties (refractive index; Vickers microhardness; HCl and H2O resistance; reflectivity; thickness) of a Bi2O3-Fe2O3-TiO2 film were studied using a water-@close@ alcohol film-forming solution (1-5% concentration) prepared from bismuth chloride, iron and tetraethoxide. The coatings were deposited on thermally polished sheet glass specimens at rates varying from 3 to 24 mm/s. It was shown that the film thickness is directly proportional to the concentration and the deposition rate of the film-forming solution used. The thickness increases more rapidly with the concentration of the solution than with the deposition rate. The coating surface is not smooth, due to the porosity of the film; porosity decreases the refractive index, reflectivity, and the microhardness of the film. 2 refs.