Growth of shaped single crystals of refractory compounds

Refractory compounds prepared from the melt of a predetermined geometry by using a shaping aid are considered. As refractory compounds are being produced, one has to deal with a number of specific features of crystal growth associated both with the operation at elevated temperatures and the chemical structure of the starting material proper. Most of the work was concerned with the growth of aluminium oxide (sapphire) which has found much practical use. Single crystals of a complex composition based on a combination of oxides (garnets, spinels) or a chemical element plus an oxide (lithium niobate, bismuth germanate or silicate) binary high boiling point temperature compounds (gallium arsenide), iron-based complex alloys, copper--aluminium nickel are also considered. Following a consideration of the mechanisms of refractory compound crystallization an attempt will be undertaken to gain an insight into the problem of control of structural imperfection of the crystal directly during crystallization. 73 ref.--AA