Sol-Gel Synthesis of Powders for the Fabrication of Ceramic Composites Based on Zircon in a Two-Step Microreactor with Intensively Swirling Flows of Reagent

Sol-gel synthesis of precursor powders of zircon, zirconium oxide and a composite based on them is performed in two ways, i.e., by reverse precipitation and the microreactor technique in a two-step microreactor with intensively swirling flows. The results of synthesis at all stages of precursor powders (1 ‒ х)(H2SiO3‒ZrO(OH)2)‒хZrO(OH)2 were compared, i.e., after calcination at 850°C and after sintering in the 1000‒1300°C temperature range. The thermal behavior of the initial nanosized compositions has been studied by differential scanning calorimetry and thermogravimetry, and dilatometry. The thermal coefficients of linear expansion of ceramic samples were estimated. The microhardness values for the obtained ceramic composites with different prehistories and thermal conductivity results are given.