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

Abstract

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.

Study of Gas Swelling Processes under Irradiation with Protons and He2+ Ions in Li4SiO4–Li2TiO3 Ceramics

“…In the case when the Li 4 SiO 4 phase prevails in the composition of ceramics, the composition is dominated by small-sized grains, completely hiding the Li 2 TiO 3 grains. In summary, having analyzed the data on the morphological features of the obtained grains, we can conclude that the change in the ratio of Li 2 TiO 3 /Li 4 SiO 4 components leads to the formation of ceramics with different geometric grain sizes, which can play an important role in determining the strength characteristics, as it was shown in [30,31] that the transition to the fine-grained fraction of ceramics has a significant effect on the resistance to radiation damage during the accumulation of nuclear reaction products and also increases the stability of ceramics to external influences.…”

“…As can be seen from the presented data comparing hardness values and resistance to single compression (i.e., the maximum amount of pressure the ceramics can withstand when compressed at a constant rate of 5 mm/min), Li 4 SiO 4 ceramics have higher strength characteristics than Li 2 TiO 3 ceramics in the case of single-component ceramics. This difference can be explained by both dimensional factors (for Li 2 TiO 3 , the grain sizes are much larger than for Li 4 SiO 4 ceramics, which leads to a lower dislocation density) and structural features of the ceramics (Li 4 SiO 4 ceramics, according to a number of studies have higher strength values [28,[31][32][33]). When varying the ratio of Li 2 TiO 3 /Li 4 SiO 4 components, it was found that an increase in the Li 4 SiO 4 content leads to an increase in hardness and maximum load, the maximum of which is reached in the case of 0.75Li 4 SiO 4 -0.25Li 2 TiO 3 ceramics, for which the increase in hardness in comparison with single-component ceramics amounted to more than 19% and the maximum load more than 15%.…”

The Influence of High-Temperature Tests on the Resistance to Degradation and Reduction in Strength Properties of Lithium-Containing Ceramics Used as Blanket Materials for Tritium Breeding

“…Therefore, comprehensive testing and analysis are indispensable for guaranteeing the safety and effectiveness of deploying these materials in fusion reactors [18][19][20]. In the realm of thermonuclear fusion [21,22], a pivotal undertaking is the exploration and advancement of blanket materials that can endure high temperatures and withstand elevated radiation levels without degradation while maintaining their strength properties. The execution of high-temperature tests serves as a crucial means to assess the performance of these materials within a fusion reactor.…”