| 摘要 |
PURPOSE:To obtain a colorless and transparent single crystal having a high refractive index, a low degree of dispersion and colorability in a wide range by restricting the concn. of Hf in ZrO2 of a ZrO2-base single crystal having a specified composition contg. yttrium oxide. CONSTITUTION:This ZrO2-base single crystal consists or 70-90mol% ZrO2 contg. <=70ppm Hf basing on the amount of Zr and of 30-10mol% Y2O3. The single crystal is manufactured by using ZrO2 contg. <=70ppm Hf. This ZrO2 is obtd. by a dry process by which Zr contg. Hf is melted in molten KCl or NaCl and separated into ZrCl4 and HfCl4 under ordinary pressure or by a wet process by which an aqueous soln. of Zr contg. Hf acidified with an inorg. acid is brought into contact with an org. solvent. When a colored single crystal is manufactured, a transition metallic oxide or a rare earth metallic oxide is added by about 0.01-5wt% of the total amount of ZrO2 and Y2O3. |
