Preparation method of calcium fluoride single crystal

Abstract

The embodiment of the invention discloses a preparation method of a calcium fluoride single crystal, in which a double-heater temperature gradient furnace is employed for preparation. The preparationmethod comprises the following steps: simultaneously heating a high-temperature zone heater and a low-temperature zone heater at 30-50 DEG C/hour; lowering the graphite crucible, keeping the constanttemperature for 2 hours after the graphite crucible is lowered, starting cooling, cooling the high-temperature zone heater and the low-temperature zone heater at the same time after the temperature ofthe high-temperature zone heater is lowered to be the same as the temperature of the low-temperature zone heater, thereby producing the calcium fluoride single crystal after the temperature is lowered to the room temperature. Compared with the prior art, according to the embodiment of the invention, the temperature of the high-temperature zone heater and the temperature of the low-temperature zone heater are adjusted to obtain the gradient zone suitable for growth of the calcium fluoride single crystal, so that seed crystal fusion and single crystal growth are accurately controlled, the crystallization rate of crystal nucleuses with different orientations is inhibited, and the purposes of greatly improving the yield of the single crystal and effectively reducing the production cost are achieved.

Description

technical field [0001] The invention relates to the field of crystal growth, in particular to a preparation method of calcium fluoride single crystal. Background technique [0002] Calcium fluoride (CaF2) is a very important optical functional crystal, which has good optical properties, mechanical properties and physical and chemical stability, and can be used as optical crystals, laser crystals and inorganic scintillation crystals. In the prior art, single crystals of calcium fluoride are usually grown by the crucible drop method or temperature gradient method with single loop temperature control, that is, single crystals of calcium fluoride are usually grown in a single temperature zone with a single heater, and the temperature gradient in the single crystal furnace is uncontrollable , it is difficult to adjust to obtain the required temperature gradient. Since the single crystal of calcium fluoride belongs to the cubic crystal system, it is very easy to crystallize, and u...

AI Technical Summary

Problems solved by technology

In the prior art, single crystals of calcium fluoride are usually grown by the crucible drop method or temperature gradient method with single loop temperature control, that is, single crystals of calcium fluoride are usually grown by a single temperature zone with a single heater, and the temperature gradient in the single crystal furnace is uncontrollable , it is difficult to adjust to obtain the required temperature gradient. Since the single crystal of calcium fluoride belongs to the cubic crystal system, it is very easy to crystallize, and usually forms multiple crystal nuclei on the crucible wall. The crystallization rate and crystal orientation of each crystal nucleus are different, which can easily lead to Calcium Fluoride Polycrystalline

In the fields of ultraviolet lens and ultraviolet window, etc., the transmittance of calcium fluoride is high, and calcium fluoride polycrystalline cannot be used.

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