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Abstract Steatite, as ceramic with composition predominantly resting on magnesium silicate, was produced from economic resources – talc, aluminosilicate clays, and either BaCO 3 or feldspar as flux. Titanium dioxide was a doping agent. Four steatite mixtures were mechanically activated in a planetary ball mill for 30, 45 or 60 min, prior to the thermal treatment. Two-step sintering with initial phase set at 1350 °C and holding period conducted at 1250 °C was applied to initiate diffusion and prevent grain growth. Thereby, a high density ceramic material with low-porous submicron structure was acquired. The effects of TiO 2 addition on densification, microstructure, and dielectric characteristics of steatites were monitored. The thermal stability of green mixtures was tested by differential thermal and thermogravimetric analyses. Changes in crystallinity and mineral phase composition were observed by the X-ray diffraction technique. Microstructural visualization with spatial arrangements of individual chemical elements on surface of the sintered ceramics was acquired by scanning electron microscopy accompanied with EDS mapping. In order to test the possibility of employment of the obtained steatites in insulation materials, electrical measurements were conducted by recording variations of the dielectric constant and loss tangent as a function of alternations in the mix-design and the mechanical activation period. [ABSTRACT FROM AUTHOR]

The focus of the study was on providing insights into interconnections between sintering and development of the crystalline microstructure, and consequently variations in dielectric behavior of four steatites fabricated from a low-cost raw material, i.e. talc. The changes, induced by the alternations of the binders (bentonite, kaolin clay) and fluxing agents (BaCO 3 , feldspar), were monitored in the temperature range 1000° to 1250 °C in which complete densification and re-crystallization of the investigated structures were accomplished. The critical points in the synthesis of steatite materials were assessed by instrumental analyses. Crystallinity changes and mineral phase transition during sintering were monitored by X-ray diffraction technique. Microstructural visualization of the samples and the spatial arrangements of individual chemical elements were achieved via scanning electron microscopy accompanied with EDS mapping. The thermal stability was observed on the green mixtures using differential thermal and thermo gravimetric analyses. Electrical measurements recorded variations of the dielectric constant (ε r ) and loss tangent (tan δ) as a function of the sintering temperature. The investigation highlighted critical design points, as well as the optimal combinations of the raw materials for production of the steatite ceramics for advanced electrical engineering applications. [ABSTRACT FROM AUTHOR]