The title of the doctoral thesis is „Synthesis of ceramic powders in the Al2O3 - SiO2 - ZrO2(Y2O3) system and production of materials”. The doctoral thesis is written in Latvian language, it contains an introduction, literature review, conclusions of literature review, methodological part, experimental part, conclusions and bibliography, which includes 76 literature sources. The doctoral thesis consists of 90 pages; includes 47 figures, 6 schemes, 8 tables. The literature review contains review of the data covering the period from 1967 to the present time concerning production of mullite - ZrO2 ceramic powder and development of ceramic materials based on the mentioned powder. The experimental part of the doctoral thesis is performed to research the method of processing of mullite - ZrO2 ceramic powder, using conventional and spark plasma sintering (SPS) methods to determine the effect on the microstructure and properties of sintered material. Particle size and morphology of ceramic powders of mullite - ZrO2, obtained by milling and hydrothermal synthesis were determined. Influence of the type of process used for sintering the powder, int. al. illite clay additive on the formation of the mullite - ZrO2 phase composition, as well as on the structure, mechanical and thermal properties was established.