The basic principles of the POESTA powder electrostatic technology used at the enamel enterprises in Ukraine are considered, the requirements for powders and protective glass enamel coatings are presented. The modern problems of the synthesis of glass enamels for POESTA are analyzed and the results of research on the development and application of single frit nickel-free glass enamel coatings for the specified purpose are presented.
The prospect of using cations of metals of variable valence in the production of biocidal glass enamel coatings for household purposes has been established. The biocidal effect of glass enamel coatings against bacteria Escherichia coli, Pseudomonas auroginosa and fungi Candida albicans, Aspergillus niger is determined by the presence of pigments containing selenides and cadmium sulfides in them. Fungicidal activity is shown for glass enamel coatings colored with pigments containing zinc and cobalt dichromates.
In the enamel - noble metal composition, the formation of a common diffuse layer has not been studied enough. The use of methods of secondary mass spectroscopy, which makes it possible to determine the elemental composition of the contacting layers, as well as electron microscopy, made it possible to determine the elemental composition of the contacting layers of these materials.
Ceramic coatings based on organosilicon polymers have been investigated, and the physical, thermal and mechanical properties of coated and uncoated heat-shielding materials have been analyzed. It was found that ceramic coatings provide an increase in the mechanical properties of a gradient heat-shielding material based on the Al 2 O 3 - SiO 2 system.
The dependence of the rate of steel oxidation under the enamel film at the temperatures of its firing is considered. In the process of firing, in some places on the surface of steel samples, covered with a layer of enamel melt, in an air atmosphere, centers of intense metal oxidation with a pronounced dark color appear. If in such a focus the melt is enriched with oxides of variable valence until it acquires electronic conductivity, then the oxidation process spreads at a constant rate in the molten enamel over the entire surface of the metal. The rate of propagation of the oxidation process depends on the viscosity and composition of the melt.
An assessment of the antibacterial effect of special glass enamel coatings, developed to protect parts of water heating equipment, is given. The effectiveness of coatings with a bactericidal agent in relation to microorganisms E. Cloacae and E. Coli is shown.
Titanium enamel for steel cookware has been developed, the composition of which contains a reduced amount of fluorides and boric anhydride in comparison with industrial enamel ESP-117. A comparative analysis of the chemical stability of enamel frits and coatings based on them is carried out. The composition of the developed enamel differs from the industrial enamel ESP-117 in its increased chemical resistance.
It has been established that the most informative and universal method for determining the biocidal properties of glass coatings is a quantitative method that takes into account the growth rate of biotest microorganisms inoculated into liquid nutrient media. It has been shown that glass-crystalline and glass-composite coatings based on glasses of the Na 2 O - CaO - ZnO - TiO 2 - Al 2 O 3 - P 2 O 5 - B 2 O 3 < / sub> - SiO 2 is determined by the presence of calcium phosphates and zinc titanates in their structure, as well as a bactericidal filler zinc phosphate. The investigated biocidal glass-crystalline and glass-composite coatings can be used to protect enameled steel dishes for various purposes, depending on their inhibitory effect. Tab. 1, ill. 1, bibliography: 15 titles.
The sol-gel method from film-forming solutions based on tetraethoxysilane and phosphoric acid solutions, with the addition of calcium and sodium salts, thin structured films were obtained in SiO 2 - P 2 O 5 - CaO - (Na 2 O) at mass content,%: 10-85 SiO 2 , 5-40 Р 2 O 5 , 10-50 CaO, 10 Na 2 O.
The physicochemical processes in solutions, which cause the transition of true solutions to colloidal ones through successive states of sol and gel, have been studied. The criterion of the film-forming ability - the viscosity of solutions - was established, and the critical value of the viscosity for obtaining high-quality films was determined. The formation of oxide systems in the films occurs during firing up to a temperature of 600 ° C. The structure of the films was investigated by infrared spectroscopy, atomic force microscopy, and X-ray phase analysis. The surface of the films obtained is characterized by a developed relief and porosity, which allows one to expect high adhesion properties of the surface. The thickness of the films obtained does not exceed 90 nm. Tab. 1, ill. 5, bibliography: 6 titles.
The features of obtaining polydisperse dry compositions for slip enameling of low-carbon steels are considered. The effect of a deflocculating additive - xanthan gum on the technological and rheological properties of slips, as well as on the quality of the coating - has been investigated.
