Synthesis and Characterization of the Properties of (1−x)Si(3)N(4)-xAl(2)O(3) Ceramics with Variation of the Components

The aim of this paper is to study the effect of variation in the component ratio of (1−x)Si(3)N(4)-xAl(2)O(3) ceramics on the phase composition, strength and thermal properties of ceramics. To obtain ceramics and their further study, the solid-phase synthesis method combined with thermal annealing of samples at a temperature of 1500 °C typical for the initialization of phase transformation processes was used. The relevance and novelty of this study lies in obtaining new data on the processes of phase transformations with a variation in the composition of ceramics, as well as determining the effect of the phase composition on the resistance of ceramics to external influences. According to X-ray phase analysis data, it was found that an increase in the Si(3)N(4) concentration in the composition of ceramics leads to a partial displacement of the tetragonal phase of SiO(2) and Al(2)(SiO(4))O and an increase in the contribution of Si(3)N(4). Evaluation of the optical properties of the synthesized ceramics depending on the ratio of the components showed that the formation of the Si(3)N(4) phase leads to an increase in the band gap and the absorbing ability of the ceramics due to the formation of additional absorption bands from 3.7–3.8 eV. Analysis of the strength dependences showed that an increase in the contribution of the Si(3)N(4) phase with subsequent displacement of the oxide phases leads to a strengthening of the ceramic by more than 15–20%. At the same time, it was found that a change in the phase ratio leads to the hardening of ceramics, as well as an increase in crack resistance.