The dissertation is aimed at developing the theoretical foundations and technological principles of large-format stoneware slabs structural strengthening and imparting antibacterial properties to their surface, which allows expanding the scope of their use.
The object of research is the technology of large-format ceramic granite slabs; principles of production and ormationprocesses of antibacterial coatings.
The subject of the study is the physico-chemical regularities of the composite type ceramic granite formation with high strength on the basis of alternative fluxing materials; recipe-technological parameters of non-fritted opacified glazes for obtaining antibacterial coatings for ceramic granite slabs.
The aim of the thesis is the development of recipe and technological parameters for obtaining high-strength large-format stoneware slabs with the antibacterial coating.
The following scientific results were obtained:
The possibility of increasing the strength of large-format stoneware slabs due to the strengthening of the ceramic matrix with mullite-silica fibers, which perform the role of a reinforcing filler and a mullite phase precursor, has been theoretically substantiated and practically confirmed. For the first time:
– generalized accumulated experience in the production of stoneware slabs, which made it possible to develop the principles of designing the masses composition based on the interconnection between phase composition and properties for different types of porceline stoneware;
– the proven using efficiency of of alternative fluxes combinations based on research of the quantitative and qualitative melting characteristics of pegmatite raw materials of the Kirovohrad deposit and enrichment products of Maidan-Vilsk alkaline kaolins;
– the mullite-silica fibers using expediency as a reinforcing filler of the ceramic matrix is shown, and the optimal additive amount and dispersion is determined, which allows to increase the strength of stoneware slabs to 57.1 MPa (by ⁓30%);
– the development methodology of non-fritte glazes for obtaining opaque coatings by directed crystallization of the target phases (rutile, cassiterite, willemite, ganite) was substantiated and implemented. Іt has been proven that the formation of such phase composition ensures a sufficient degree of coatings opacification (KDR 77–84 %) and a complex of high operational properties: microhardness (7500–7800 MPa), acid resistance (99.6–99.9 %) and heat resistance (>10 cycles);
– the optimal ratios of phase-forming oxides in the combinations (ZnO+SnO2) and (TiO2+SnO2) were determined, which made it possible to obtain glass-crystalline coatings with given phase composition, which capable of inhibiting the microorganisms growth and preventing the biofilm formation on the stoneware slabs surface.
As a testing result in the laboratory of NSU UKRNDIEP, it was established that the developed glass-crystalline coatings have pronounced antibacterial properties relative to the tested bacterial cultures and are able to prevent microbial contamination of the porcelain tiles surface.
The results of thesis research have been applied in the educational process of the Department "Technologies of Ceramics, Refractories, Glass and Enamels" of the National Technical University "Kharkiv Polytechnic Institute" in the bachelors and masters training.
Keywords: Large-format stoneware, reinforcing aggregate, mullite-silica fibers, sintering, liquidus, strength, water absorption, multicomponent systems, energy and resource saving, glass crystal coatings, antibacterial effect, heat resistance, abrasion resistance, "composition-property" diagram, structure and phase composition.
