Study of the gas inclusions in Al_2O_3/Y_3Al_5O_(12) and Al_2O_3/Y_3Al_5O_12/ZrO_2 eutectic fibers grown by laser floating zone

摘要

Gas bubbles appear in some metal oxides grown by directional solidification in air when high growth rates are used. The incorporation of bubbles in Al_2O_3-YAG (AY) and Al_2O_3-YAG-ZrO_2 (AYZ) eutectic crystals grown using the laser floating zone method was investigated. The effect of different growth experimental parameters was considered. Growth rate, rod diameter and growth atmosphere were found to be determinant in order to reduce the gas inclusions. The optimization of the growth parameters allowed to grow AY and AYZ eutectic crystals free of bubbles at very high growth rates at which interphase spacings smaller than 300 nm were obtained.