Hydrothermal synthesis of starting mixture for mullite-ZrO2 ceramics Results of the effect of hydrothermal synthesis of the starting mixture from chemical reagents and illite clays on the phase composition and structure, as well as some properties of mullite-ZrO2 ceramics have been given. It is shown that in the sintered ceramic material mullite and ZrO2 (tetragonal) are formed and developed with an increasing of sintering temperature from 1100 to 14000C. It is indicate on the presence of closed pores in obtained ceramics. Densification and consequently pressure resistance increases with the sintering temperature, as well as with the addition of illite clay. Thermal shock measurements shows that by temperature difference up to 1000/20 0C by thermal shock and also by illite clay additive (accordingly) modulus of elasticity reaches the value 35 and 95 GPa, while at 500/20 - 20 and 22 GPa