Effect of SiO2 on the growth and perfection of stabilized monocrystals ZrO2

ZrO2-R2O3 crystals, where R - Y, Eu, Gd, Yb (Si concentration by the chemical analysis data approximately 10-2 mass.%) and a series of ZrO2 crystals -12 mol.% of Y2O3 with deliberately introduced SiO2 in 0.05-0.5 mass.% concentration, have been grown. It is shown that the presence of SiO2 in the initial charge for growing fianite produces negative effect on the growth and perfection of monocrystals, causing light scattering in the crystals, formation of the lattice structure and massive inclusions of the second phase. SiO2 impurity of 0.2 mass.% in the charge of ZrO2 composition - 12 mol.% Y2O3 does not prevent monocrystal preparation at 10 mm/hour growth rate, but the crystals scatter the light intensively. Exceeding SiO2 content 0.5 mass.% causes obtaining a polycrystalline block. Silicon dioxide is shifted by the crystal front in the process of crystal growth. Formation of massive inclusions is observed, as a rule, in upper parts of the crystals prepared in the end of the process