The role of reactive phase transformations in composite ceramics in changing strength and thermal characteristics

Abstract

The paper presents the results of the assessment of the influence of variations in the ratio of components in composite (1-x)ZrO₂ – xSiC ceramics on the change in phase composition caused by the initialization of reactive phase transformations, as well as determination of the role of phase transformations on the change in strength and thermal characteristics. It has been established that control over the phase composition of composite (1–x)ZrO₂–xSiC ceramics allows for the targeted optimization of their strength properties, and the most favorable combination of strength characteristics is achieved at intermediate SiC concentrations of 0.2 – 0.3 M, ensuring a high level of mechanical reliability of materials under conditions of intense external influences. The results of thermal shock tests confirm that the highest resistance to sudden temperature effects is achieved in composite (1–x)ZrO₂–xSiC ceramics with a SiC content of 0.2 – 0.3 M, which ensures an optimal balance between thermal conductivity, mechanical strength, and the ability of the structure to relax thermally induced stresses. The data obtained are of great practical importance for assessment of the performance of these materials under conditions of non-stationary temperature conditions and emergency situations typical for the operation of inert matrices of dispersed nuclear fuel.