| 摘要 |
PURPOSE:To obtain the titled material capable of providing a single crystal not contg. any bubbles irrespective of the kind and amt. of a colorant and having excellent transparency and gloss by sintering the power of raw materials such as alpha-Al2O3 into the shape of a round rod at specified high temps. CONSTITUTION:alpha-Al2O3 is used as the raw material powder of a corundum crystal and an alexandrite crystal, and metallic oxides of Cr, Ni, Fe, Ti, etc. are added in an appropriate amt. in correspondence with the desired crystal as a colorant. The mixture is then sintered at 800-1,500 deg.C into the shape of a round rod, and the raw material for growing a single crystal by the infrared- condensing floating zone method (FZ method) is obtained. The material is then suspended from the upper shaft of the FZ device, and a seed crystal provided to the lower shaft is heated to form a melt between the raw material and the seed crystal. A single crystal is grown on the seed crystal by moving both crystal and material downward at <0.3mm./H growth rate.
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