Фазовый состав, структура и некоторые свойства материалов на основе ВКВС боксита композиционного состава в системе Al2O3 – SiO2 – SiC

Abstract

The effect of temperature and duration of heat treatment of samples based on a highly concentrated ceramic binder suspension (HCBS) of a composite composition (bauxite + 11% VDKS), as well as with an additional content of 15% silicon carbide on their phase composition, structure, and some properties is studied. Long-term heat treatment (60 and 120 hours) in the temperature range 1300 - 1400 ° C is carried out in a tunnel kiln for firing dinas. In the process of heat treatment, the process of formation of secondary mullite, the oxidation of SiC followed by mullite formation, proceeds. The influence of the heat treatment duration on the phase composition, as well as the strength, apparent density, growth, SIC oxidation state, and bending strength of samples containing 15% SiC are characterized. It is found that the minimum porosity value (2.7 %) is observed when the heat treatment duration is 8 hours. This drop in porosity and a slight decrease in density is due to a certain degree of mullitization or SiC oxidation, but also to the formation of a significant volume of closed porosity. With increasing the duration of the firing process to 60 and 120 hours, the porosity indicators increase significantly, and the density decreases sharply.