阅读说明：本技术 一种用于红外监测的硫化锌晶体的制备方法 (Preparation method of zinc sulfide crystal for infrared monitoring ) 是由 朱亮 于 2020-05-28 设计创作，主要内容包括：本发明公开了一种用于红外监测的硫化锌晶体的制备方法,属于硫化锌晶体的制备领域。本发明包括如下步骤：装料、预压、烘干、结晶,本发明中通过采用液压机对硫化锌进行预压,使其体内的气体迅速排出,从而提高致密度形成硫化锌压块；硫化锌压块在真空炉中通过热的作用,在熔点以下直接升华再结晶从而获得提纯后的ZnS晶体。从而克服了现有技术中在制备热压硫化锌晶体材料的过程中导致硫化锌材料中的内部缺陷,造成对光的散射的缺陷。(The invention discloses a preparation method of zinc sulfide crystals for infrared monitoring, and belongs to the field of preparation of zinc sulfide crystals. The invention comprises the following steps: the method comprises the steps of loading, prepressing, drying and crystallizing, wherein zinc sulfide is prepressed by adopting a hydraulic press, so that gas in the zinc sulfide is rapidly discharged, and the compactness is improved to form a zinc sulfide pressing block; the zinc sulfide pressed block is directly sublimated and recrystallized below the melting point in a vacuum furnace under the action of heat, so that the purified ZnS crystal is obtained. Thereby overcoming the defect of light scattering caused by the internal defect in the zinc sulfide material in the process of preparing the hot-pressing zinc sulfide crystal material in the prior art.)

1. A preparation method of zinc sulfide crystals for infrared monitoring is characterized by comprising the following steps:

step 1), charging: uniformly filling zinc sulfide powder with a certain specification into a mold;

step 2), prepressing: placing the die in a hydraulic machine for prepressing, selecting different pressures for prepressing according to different die heights, wherein the hydraulic machine pressure is 20-30T when the die is within 2cm, and the hydraulic machine pressure is 60-70T when the die is 3-5 cm;

step 3), drying: placing the pre-pressed mould in an oven for drying, wherein the temperature of the oven is set to be 100-;

step 4), crystallization: and (3) placing the dried mould in a vacuum furnace, sublimating and recrystallizing the zinc sulfide pressing block in the vacuum furnace, setting the heating temperature of the vacuum furnace to 800-900 ℃, heating for 3-6h, and taking out the zinc sulfide crystal from the vacuum furnace.

2. The method for preparing zinc sulfide crystals for infrared monitoring as claimed in claim 1, wherein the heating temperature in step 4) is 820-850 ℃.

3. The method for preparing zinc sulfide crystals for infrared monitoring as claimed in claim 2, wherein the heating temperature in the step 4) is 850 ℃ and the heating time is 5 h.

Technical Field

The invention relates to a preparation method of a zinc sulfide crystal, in particular to a preparation method of a zinc sulfide crystal for infrared monitoring.

Background

Zinc sulfide is a widely used wide bandgap semiconductor material. Has good transmission performance in the infrared band range and simultaneously has good mechanical stability and thermal stability. The zinc sulfide is widely applied to military and civil fields such as infrared tracking, searching, identifying, detecting and guiding, and the zinc sulfide is used as a basic material and has wide requirements in the technical field of infrared imaging. The zinc sulfide can still keep the transmittance above 60% at 500 ℃, and is a medium-long wave infrared optical window 1: 3 and one of the main candidate materials for fairings. The saturated vapor pressure of zinc sulfide in the vicinity of the melting point (1830 ℃ C.) is 375kPa, so that it is difficult to obtain a large amount by the pressureless sintering methodA zinc sulfide crystalline material of size. In the process of preparing hot-pressed zinc sulfide crystal materials, S is often introduced during 1) the shrinkage of a mold to extrude crystals in the cold pressing process of the crystals after the hot pressing is finished, and 2) the purification of zinc sulfide^2-Cavities, which in turn lead to internal defects in the zinc sulfide material, cause scattering of light, and therefore it is desirable to provide a preparation method that improves the microstructure in the zinc sulfide material, increasing the optical properties of the zinc sulfide crystals.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provides a preparation method of zinc sulfide crystals for infrared monitoring.

The technical scheme of the invention is as follows: a preparation method of zinc sulfide crystals for infrared monitoring is characterized by comprising the following steps:

step 1), charging: uniformly filling zinc sulfide powder with a certain specification into a mold;

step 2), prepressing: placing the die in a hydraulic machine for prepressing, selecting different pressures for prepressing according to different die heights, wherein the hydraulic machine pressure is 20-30T when the die is within 2cm, and the hydraulic machine pressure is 60-70T when the die is 3-5 cm;

step 3), drying: placing the pre-pressed mould in an oven for drying, wherein the temperature of the oven is set to be 100-;

step 4), crystallization: placing the dried mould in a vacuum furnace, sublimating and recrystallizing the zinc sulfide pressing block in the vacuum furnace, setting the heating temperature of the vacuum furnace to 800-900 ℃, heating for 3-6h, and taking out zinc sulfide crystals from the vacuum furnace;

the further technical proposal is that the heating temperature in the step 4 is 820-850 ℃;

according to a further technical scheme, the heating temperature in the step 4 is 850 ℃, and the heating time is 5 hours.

The invention has the beneficial effects that:

s is introduced for solving the problem that crystals are extruded by a die and purification in the prior art^2-The cavity is formed after the mould is pre-pressed by adopting a hydraulic pressAnd drying, and then carrying out sublimation recrystallization on the zinc sulfide material to obtain zinc sulfide crystals. In the prior art, two major factors for measuring the ZnS crystal quality are measured; infrared transmittance and bending strength. For zinc sulfide materials, the porosity in the body decreases with increasing pressure, and the permeability increases with increasing density of the material. Therefore, the zinc sulfide is pre-pressed by the hydraulic press, so that gas in the zinc sulfide is rapidly discharged, and the compactness is improved to form a zinc sulfide pressing block; the zinc sulfide pressed block is directly sublimated and recrystallized below the melting point in a vacuum furnace under the action of heat, so that the purified ZnS crystal is obtained.

Detailed Description

The invention provides a preparation method of zinc sulfide crystals for infrared monitoring.

The technical scheme of the invention is as follows: a preparation method of zinc sulfide crystals for infrared monitoring is characterized by comprising the following steps:

step 1), charging: uniformly filling zinc sulfide powder with a certain specification into a mold;

step 2), prepressing: placing the die in a hydraulic machine for prepressing, selecting different pressures for prepressing according to different die heights, wherein the hydraulic machine pressure is 20-30T when the die is within 2cm, and the hydraulic machine pressure is 60-70T when the die is 3-5 cm;

step 3), drying: placing the pre-pressed mould in an oven for drying, wherein the temperature of the oven is set to be 100-;

step 4), crystallization: placing the dried mould in a vacuum furnace, sublimating and recrystallizing the zinc sulfide pressing block in the vacuum furnace, setting the heating temperature of the vacuum furnace to 800-900 ℃, heating for 3-6h, and taking out zinc sulfide crystals from the vacuum furnace;

among them, the zinc sulfide powder in step 1 is a commercially available raw material, which contains many impurities and must be purified. In the prior art, hydrogen sulfide gas is usually added at high temperature for heating and purification, but the method can generate an S-rich phenomenon; therefore, it is necessary to add hydrogen gas at a further high temperature to remove S, but at this time, S appears^2-A cavity.

Therefore, in the invention, the holes and air holes in the zinc sulfide are eliminated by prepressing in the step 2, the density of the crystal is improved, and the optical transmission performance of the material can be improved;

in the step 4, the raw materials are fully purified by a sublimation and recrystallization mode,

the invention will be further illustrated and understood by the following non-limiting examples.