STUDY OF TECHNOLOGICAL PARAMETERS OF OBTAINING CELSIANE AND SLAWSONITE CERAMICS USING SINGLE-STAGE TECHNOLOGY

Abstract

On the basis of the RO–Al2O3–SiO2 system, radiotransparent ceramic materials of cordierite, celsian, and anorthite composition, which have low dielectric characteristics, are obtained. These requirements are met by one of the main phases of the BaO–Al2O3–SiO2 system – celsian (BaAl2Si2O8), the melting point of which is 1740 °C, and the beginning of active phase formation occurs at a processing temperature of 1300 °C, as well as one of the main phases of the SrO–Al2O3–SiO2 is slavsonite (SrAl2Si2O8), which undergoes congruent melting at a temperature of 1765 °C, and the beginning of active phase formation occurs at a processing temperature of 1400 °C. The purpose of the work is to study the technological parameters of obtaining celsian and slavsonite ceramics by one-stage technology. According to the subsolidus structure of the three-component system RO–Al2O3–SiO2 (RO = ВаО, SrO), it is advisable to synthesize the necessary phases from pure raw materials and, taking into account the presence of impurities that impair the dielectric characteristics, the synthesis of the necessary crystalline phases is carried out from technical raw materials. Figurative points of the compositions of the selected compounds correspond to their stoichiometric composition (for slavsonite, wt. %: SrO – 31,99; Al2O3 – 30,93; SiO2 – 37,08; for celsian, wt. %: BaO – 40,85; Al2O3 – 27,17; SiO2 – 31,98). It was established that the physical characteristics of the obtained samples improve with an increase in the firing temperature by 100 °C, but they are far from the desired level. The dielectric characteristics of the obtained materials are within the requirements for radio-transparent materials. Taking into account the investigated physical properties and the obtained radiographs of fired samples in order to obtain a densely sintered material, it was decided to investigate model compositions with the addition of intensifying additives and to study their influence on the properties of fired samples