Crystal growth on Hg.sub.3 TeO.sub.6
AssigneeAllied Chemical Corporation
InventorZvi Blank
Life of this patent
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Abstract
Single crystals of Hg.sub.3 TeO.sub.6, which are useful in, for example, acousto-optic applications, are grown on rotating seed crystals in aqueous solution at an elevated temperature. A two-step process is employed in which supersaturation is achieved by a substantially homogeneous increase in pH throughout the solution under substantially isothermal conditions, followed by a decrease in temperature at substantially constant pH. The homogeneous increase in pH is attained by adding a compound such as urea whose rate of hydrolysis may be controlled by solution pH and temperature. The use of such a compound ensures thorough mixing of the compound in the solution before the compound hydrolyzes to produce a pH-altering substance.
Claims6
A process for growing single crystals of mercury tellurate (Hg.sub.3 TeO.sub.6) on rotating seed crystals of Hg.sub.3 TeO.sub.6 from a slightly undersaturated highly acidic aqueous solution of pH near 0 at an elevated temperature which comprises
- a. adding a hydrolyzing compound having a controllable rate of hydrolysis to the slightly undersaturated aqueous solution maintained under substantially isothermal conditions to increase the pH of the solution to a value of about 1.5 substantially homogeneously throughout the solution and to effect crystal growth;
- and
- b. then slowly reducing the solution temperature to about room temperature at substantially constant pH to complete the crystal growth.
Dependencies are inferred from the claim text.