Abstract:
1,153,802. Synthetic quartz. WESTERN ELECTRIC CO., Inc. 8 Sept., 1966 [24 Sept., 1965], No. 40112/66. Heading C1A. Quartz crystals are synthesized by disposing a quartz crystal seed and a mass of nutrient SiO 2 in a pressure vessel, at least 60% of the volume of which is filled with an aqueous medium comprising sodium ions, lithium ions and nitrite anions in concentrations of at least 0À2, 0À02 and 0À02 molar respectively, sealing the vessel and heating it to obtain a temperature of at least 300‹ C. in the aqueous medium while maintaining the temperature of the nutrient mass at least 15‹ C. above that of the seed. The preferred sources of ions are NaOH or Na 2 CO 3 and LiNO 2 . The temperature of the aqueous medium is preferably 350-573‹ C. and the concentration of nitrite ions is preferably 0À02-0À15.
Abstract:
A COMMERCIAL TECHNIQUE FOR GROWTH OF OPTICAL GRADE MATERIAL OF THE NOMINAL COMPOSITION BA2NANB5/15 IS DESCRIBED. THE USUALLY ENCOUNTERED CRACKING PROBLEM IS MINIMIZED BY FOLLOWING A CRITICALLY SLOW COOLING RATE OVER A SHORT TEMPERATURE INTERVAL OF FROM ABOUT 600*C. TO ABOUT 400*C. INITIAL COOLING FROM THE CRYSTALLIZING TEMPERATURE TO THIS INTERVAL AND FROM THIS RANGE TO ROOM TEMPERATURE IS NOT CRITICAL AND MAY BE RAPID.