| 摘要 |
PURPOSE:To produce a high-quality corundum crystal free from voids, by sintering powdery mixture composed of Al ammonium carbonate, etc. and Co sulfate, etc. at a specific ratio, and synthesizing the objective corundum from the obtained sintered material by the focused floating zone melting process. CONSTITUTION:An Al compound selected from the ammonium carbonate, hydroxide, ammonium sulfate and sulfate and a Co compound selected from the sulfate, hydroxide and chloride are mixed together at a ratio close to the compositional ratio of green sapphire by a ball mill, and the mixture is thermally decomposed at about 800-1,200 deg.C to obtain the raw material powder. The powder is formed to a columnar rod by a rubber-press under the pressure of about 3t/cm<2>, and is sintered in an inert gas atmosphere at about 1,300-1,600 deg.C to obtain a raw material rod. The rod is used as the raw material, and a green sapphire is grown from the raw material by the focused floating zone apparatus furnished with an ellipsoidal reflector 1 and a halogen lamp 2 using a corundum crystal as the seed crystal 7. A green sapphire free from voids and colored uniformly throughout the crystal can be produced by this process. |
