STUDY OF THE INFLUENCE OF MgO DOPING ON THE THERMOPHYSICAL PROPERTIES OF CERAMICS BASED ON LITHIUM METAZIRCONATE

Abstract

The paper presents the results of studying the effect of doping with magnesium oxide (MgO) of lithium-containing ceramics based on lithium metazirconate (Li2ZrO3) on the change in the thermophysical parameters of ceramics. The method of mechanochemical synthesis followed by high-temperature annealing at a temperature of 1300 °C, used to initiate the processes of phase transformations from structural ordering, was chosen as the main method for obtaining ceramics, as well as for performing MgO doping processes. In the course of the studies, it was found that an increase in the concentration of the MgO dopant above 0.10 mol leads to the formation of impurity inclusions in the structure of ceramics in the form of a tetragonal phase MgLi2ZrO4, the content of which increases with an increase in the concentration of the dopant. In the case of a dopant concentration of 0.25 mol, the phase composition of ceramics is an equiprobable distribution of two phases, monoclinic Li2ZrO3 and tetragonal MgLi2ZrO4. In the course of measuring thermophysical parameters, it was found that the formation of the MgLi2ZrO4 phase in the composition of ceramics leads to an increase in the thermal conductivity by 5–10%, and in the case of an equiprobable distribution of phases in two-phase MgLi2ZrO4– Li2ZrO3 ceramics, the increase in thermal conductivity is more than 25% in comparison with undoped ceramics. An increase in the efficiency of heat-conducting properties for two-phase ceramics is due to an increase in the rate of phonon heat transfer due to additional interfacial boundaries, as well as an increase in the degree of structural ordering and density of ceramics.