Preparation process and equipment of calcium fluoride

Abstract

The embodiment of the invention discloses a preparation process of calcium fluoride, which comprises the following steps: vacuumizing to enable the vacuum degree in a furnace body to be not less than10<-3> Pa, and simultaneously heating a high-temperature zone heater and a low-temperature zone heater at 30-50 DEG C / h; after the temperature of the high-temperature zone heater is reduced to be thesame as that of the low-temperature zone heater, simultaneously cooling the high-temperature zone heater and the low-temperature zone heater to 1000-1200 DEG C at the same time; after crystal crystallization is finished, regulating the temperature difference between the high-temperature zone heater and the low-temperature zone heater to be zero; and carrying out in-situ annealing treatment on thecalcium fluoride crystal, and cooling the furnace to room temperature at a speed of 5-20 DEG C / h after the annealing is finished. By adjusting the temperatures of the high-temperature zone heater andthe low-temperature zone heater, a gradient zone suitable for growth of the calcium fluoride single crystal is obtained, 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 productioncost 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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