Study of the Effect of Two Phases in Li₄SiO₄-Li₂SiO₃ Ceramics on the Strength and Thermophysical Parameters

The paper studies the effect of Li₂SiO₃/Li₄SiO₄ phase formation in lithium-containing ceramics on the strength and thermophysical characteristics of lithium-containing ceramics, which have great prospects for use as blanket materials for tritium propagation. During the phase composition analysis of the studied ceramics using the X-ray diffraction method, it was found that an increase in the lithium component during synthesis leads to the formation of an additional orthorhombic Li₂SiO₃ phase, and the main phase in ceramics is the monoclinic Li₄SiO₄ phase. An analysis of the morphological features of the synthesized ceramics showed that an increase in the Li₂SiO₃ impurity phase leads to ceramic densification and the formation of impurity grains near grain boundaries and joints. During determination of the strength characteristics of the studied ceramics, a positive effect of an increase in the Li₂SiO₃ impurity phase and dimensional factors on the strengthening and increase in the resistance to external influences during compression of ceramics was established. During tests for resistance to long-term thermal heating, it was found that for two-phase ceramics, the decrease in strength and thermophysical characteristics after 500 h of annealing was less than 5%, which indicates a high resistance and stability of these ceramics in comparison with single-phase orthosilicate ceramics.