Boron-free environmentally friendly protective glazes for carbon-bonded isostatically pressed refractory functional components

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The focus of the scientific project is dealing with the scientific exploration of boron-free passivation glaze layers against oxygen attack of carbon bonded isostatically-pressed refractory functional components and the understanding of the mechanisms. This implements the abandonment of boron and especially of sodiumtetraborate, which is since 2010 as very susceptible for healthy reasons dealing with the fertility declared. Especially in carbon bonded Al2O3-C materials the impact of CaO-MgO-Al2O3- und CaO-MgO-SiO2-additives with or without P and K will be investigated. Based on the gained knowledge model components of stoppers and nozzles will be explored according to their corrosion- and oxygen-resistance as well as clogging performance in contact with steel melt in a special steel casting simulator. Heating microscopy, HT-XRD as well as SEM/EBSD/FIB analysis will support the interpretation of the formation of the passivation glaze layer as a function of the processing features such as cycling pressing, a) without pulsation, b) with pulsation at the maximum pressure and c) pulsation during pressing up. Based on pair correlation functions and order parameters the micro- structure will be described and correlated to the achieved properties dealing with the oxidation-, corrosion- and cloghing-performance as well as the achieved mechanical properties. In addition with the aid of ASPEX analysis the impact of the new glaze on the formation of inclusions (their chemistry, size and population) in the steel will be investigated.