| 摘要 |
PURPOSE:To obtain the titled raw material capable of providing a single crystal not contg. any bubbles and having excellent transparency and gloss by compression-molding high-purity raw material powder and a colorant into the shape of a round rod, and sintering the rod. CONSTITUTION:Al2O3 and BeO each having >=99.99% purity are used as the raw material powder for a corundum crystal and an alexandrite crystal. Then Cr2O3, NiO, Fe2O3, TiO, etc, each having >=99.99% purity are added to the powder as colorants, and sufficiently mixed. The mixture is then compression-molded into a round rod which is sintered in an electric furnace to obtain the raw material for growing a single crystal with the infrared-condensing floating zone method (FZ method). The material is then suspended from the upper shaft of an FZ device, and a seed crystal provided to the lower shaft is heated to obtain a melt between the raw material and the seed crystal. A single crystal is grown on the seed crystal by moving both raw material and seed crystal downward at 2.0mm./H growth rate.
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