Preparation of Dense Ceramics Based on Aluminum–Magnesium Spinel by Forming Solid Solutions in the MgAl2O4–Ga2O3 System

The main results of studies devoted to the production of dense ceramics, namely ceramics based on aluminum–magnesium spinel (AMS), are presented. It is established that the introduction of modifying additives contributes to the production of dense ceramics with improved performance characteristics. The main trends in the action of sintering additives that do not react with the basic compound are described. It is found that the additive not only plays the role of a crystal growth restrictor during the elimination of porosity, but also intensifies the process of removing the pores. The defect formation schemes are drawn up for yttrium oxide and gallium oxide with aluminum–magnesium spinel. Additives that dissolve in the magnesium sublattice and create a high concentration of vacancies in the aluminum sublattice have a particularly positive effect on the porosity removal process. It is experimentally proven that the method of introducing the additive (for example, introducing gallium oxide) plays an important role in improving the properties of ceramics based on aluminum–magnesium spinel. If the additive is added to the AMS powder, then the relative density of the sample turns out to be higher than in the case of addition to the precursor and reaches to 91% of the theoretical value.