| 摘要 |
PURPOSE:To avoid crack generation accompaning phase transformation and to manufacture kunzite single crystals efficiently and stably by crystallizing a raw material mixture with a unidirectional coagulation method while controlling the temp. gradient. CONSTITUTION:A floating zone method is especially suitablbe for the above-mentioned unidirectional coagulation method. Namely, 1pts.mol lithium oxide power, 1pts.mol alumina power, 1pts.mol silicon oxide power and 0.0001-0.05pts.mol metal (oxide) power are mixed and the mixture is molded with rubber-press and sintered to make raw materials. The raw material 1 is grown into a crystal 4 by using the floating zone. (Marks 2, 3, 5 and 6 show a high frequency coil, a heat insulator, a heater and melt respectively.) In this case, the crank generation due to the phase transformation is prevented by keeping the temp. gradient to the transformation point of crystallization to about 4-10 deg.C/cm and the temp. gradient after the transformation point to about 0.5-4 deg.C/cm.
|
