阅读说明：本技术 采用提拉法生长翠绿宝石晶体的方法 (Method for growing emerald gem crystal by Czochralski method ) 是由 王世武 许辉 李瑞茂 聂奕 于 2021-03-15 设计创作，主要内容包括：本发明涉及激光晶体制造技术领域,尤其涉及一种采用提拉法生长翠绿宝石晶体的方法,采用提拉法籽晶定向生长,包括如下步骤：接种、放肩、等径生长、收尾及降温,最终得到翠绿宝石晶体,所得到翠绿宝石晶体利用率达到80％。本发明中当收尾结束后停止旋转和提拉并开始降温,通过P I D调节功率实现对晶体生长速率的控制,从而实现对晶体结晶速度的控制。本发明具有生长速度可控、生长尺寸大、重复性好的优点,适合工业化生产翠绿宝石晶体。(The invention relates to the technical field of laser crystal manufacturing, in particular to a method for growing emerald diamond crystals by adopting a pulling method, which adopts a pulling method to carry out seed crystal directional growth and comprises the following steps: inoculating, shouldering, growing in an equal diameter, ending and cooling to finally obtain the emerald diamond crystal, wherein the utilization rate of the obtained emerald diamond crystal reaches 80%. In the invention, after ending, the rotation and the pulling are stopped and the temperature is reduced, and the crystal growth rate is controlled by adjusting the power through P ID, thereby realizing the control of the crystal crystallization speed. The method has the advantages of controllable growth speed, large growth size and good repeatability, and is suitable for industrial production of emerald precious stone crystals.)

1. The Czochralski method is adopted to grow emerald sapphire crystals, and the Czochralski method is adopted to carry out directional growth of seed crystals, and is characterized in that: the method comprises the following steps:

inoculation: before inoculation, the seed crystal is rotated, the inoculation condition is observed in real time by using a ccd camera, and when inoculation is carried out, the weight curve change shown by the observation software is observed, the curve is a horizontal straight line, and pulling is started;

shouldering: in the shouldering process, the diameter d of the crystal grows to 50-70% of the diameter of the crucible from 5-10 mm step by step, and the diameter d of the crystal linearly changes along with the shouldering length L;

and (3) isometric growth: in the process of isometric growth, according to the quality change condition of the crystal growing in unit time, the PID algorithm is used for carrying out feedback control on the heating power, so that the active control of the crystal growing speed is realized, and the weight of the crystal is in accordance with the weight obtained by calculation of the design appearance;

ending: ending after the equal-diameter growth length reaches the design requirement, adjusting the power through PID in the ending process to ensure that the diameter of the crystal begins to be reduced, and ending the ending growth;

cooling: and cooling the crystal to room temperature to obtain the emerald crystal.

2. The method of growing emerald diamond crystals using the czochralski method according to claim 1, wherein: the seed crystal is a cuboid seed crystal with a cross section of 5 multiplied by 5 to 10 multiplied by 10 mm.

3. The method of growing emerald diamond crystals using the czochralski method according to claim 1, wherein: rotating the seed crystal before inoculation at the speed of 2-20 rpm in the inoculation process; the pulling speed in the inoculation process is 0.2-2 mm/h.

4. The method of growing emerald diamond crystals using the czochralski method according to claim 1, wherein: the shoulder-laying method comprises the following specific steps:

pulling the crystal according to 0.2-2 mm/h until the diameter D of the crystal is 50-70% of the diameter D of the crucible, and controlling the length-diameter ratio and the diameter ratio of the crystal to be 1: 1, in the upward pulling process, the crystal rotates at the speed of 2-20 rpm;

and when the diameter of the crystal obtained in the step is larger than the length of the crystal by about 10-15 mm, controlling the crystal to start to have the same diameter.

5. The method of growing emerald diamond crystals using the pulling method according to claim 4, wherein: wherein the diameter d of the crystal satisfies 50mm < d <100mm, and the shouldering length L satisfies 50mm < L <70 mm.

6. The method of growing emerald diamond crystals using the czochralski method according to claim 1, wherein: after the ending growth is finished, the diameter of the crystal is 60-80% of the diameter of the equal diameter, and the ending length is 40-60% of the shouldering length.

7. The method of growing emerald diamond crystals using the czochralski method according to claim 1, wherein: the specific steps of cooling are as follows:

after growth is finished, entering a cooling stage, stopping rotation, and reducing 500w in 20 minutes under the current power for finishing growth;

after the steps are finished, the power is reduced to 0 from the current power for 72-96 h at the speed of 200-300 w/h, and after the temperature reduction procedure is finished, the temperature of the crystal is reduced to the room temperature.

8. The method of growing emerald diamond crystals using the czochralski method according to any one of claims 1 to 7, wherein: the crystal growth condition is observed in real time by adopting an infrared CCD camera in the whole crystal growth process.

9. An emerald gemstone crystal, comprising: prepared by a method of growing emerald crystals by the Czochralski method according to any one of claims 1 to 7.

Technical Field

The invention relates to the technical field of laser crystal manufacturing, in particular to a method for growing emerald crystal by adopting a pulling method.

Background

The laser made of emerald crystal has wide application range, and relates to the fields of scientific research, military, medical treatment, atmospheric measurement, photoelectronic technology, etc.

The growth of emerald crystals is difficult, and it is difficult to obtain high-quality large-size crystals. Although the method is researched by scientific research units for many years, the method still does not make a major breakthrough, the quality of the grown emerald crystal is poor, the crystal shape is flat, the utilization rate is almost zero, and the growth process of the emerald crystal is incomplete.

Disclosure of Invention

Aiming at the existing technical problems, the invention provides a method for growing emerald precious stone crystals by adopting a pulling method, which solves the technical problems that although the method is researched by scientific research units for many years at present, the method still does not get a great breakthrough, the quality of the grown emerald precious stone crystals is poor, the crystal shape is flat, the utilization rate is almost zero, and the growth process of the emerald precious stone crystals is incomplete.

In order to achieve the purpose, the invention provides the following technical scheme:

the method for growing the emerald gem crystal by the Czochralski method is adopted to carry out the directional growth of the Czochralski seed crystal, and comprises the following steps:

inoculation: before inoculation, the seed crystal is rotated, the inoculation condition is observed in real time by using a ccd camera, and when inoculation is carried out, the weight curve change shown by the observation software is observed, the curve is a horizontal straight line, and pulling is started;

shouldering: in the shouldering process, the diameter d of the crystal grows to 50-70% of the diameter of the crucible from 5-10 mm step by step, and the diameter d of the crystal linearly changes along with the shouldering length L;

and (3) isometric growth: in the process of isometric growth, according to the quality change condition of the crystal growing in unit time, the PID algorithm is used for carrying out feedback control on the heating power, so that the active control of the crystal growing speed is realized, and the weight of the crystal is in accordance with the weight obtained by calculation of the design appearance;

ending: ending after the equal-diameter growth length reaches the design requirement, adjusting the power through PID in the ending process to ensure that the diameter of the crystal begins to be reduced, and ending the ending growth;

cooling: and cooling the crystal to room temperature to obtain the emerald crystal.

In some of the embodiments, the seed crystal is a cuboid seed crystal with a cross section of 5 × 5-10 × 10 mm.

In some embodiments, the seed crystal is rotated at the speed of 2-20 rpm before inoculation in the inoculation process; the pulling speed in the inoculation process is 0.2-2 mm/h.

In some embodiments, the shouldering step comprises:

pulling the crystal according to 0.2-2 mm/h until the diameter D of the crystal is 50-70% of the diameter D of the crucible, and controlling the length-diameter ratio and the diameter ratio of the crystal to be 1: 1, in the upward pulling process, the crystal rotates at the speed of 2-20 rpm;

and when the diameter of the crystal obtained in the step is larger than the length of the crystal by about 10-15 mm, controlling the crystal to start to have the same diameter.

In some of these embodiments, wherein the crystal diameter d satisfies 50mm < d <100mm, the shouldering length L satisfies 50mm < L <70 mm.

In some embodiments, after the ending growth, the diameter of the crystal is 60-80% of the diameter of the constant diameter, and the ending length is 40-60% of the shouldering length.

In some embodiments, the cooling comprises the following steps:

after growth is finished, entering a cooling stage, stopping rotation, and reducing 500w in 20 minutes under the current power for finishing growth;

after the steps are finished, the power is reduced to 0 from the current power for 72-96 h at the speed of 200-300 w/h, and after the temperature reduction procedure is finished, the temperature of the crystal is reduced to the room temperature.

The Czochralski method is adopted to grow the emerald sapphire crystal, and an infrared CCD camera is adopted to observe the crystal growth condition in real time in the whole crystal growth process.

In some embodiments, an emerald crystal is provided, produced using a method of growing an emerald crystal using the czochralski method as described above.

Compared with the prior art, the invention has the following beneficial effects:

the invention integrates the advantages of controllability and good repeatability of the Czochralski method, is a novel emerald sapphire crystal growth method, is suitable for industrial batch production of emerald sapphire crystals, and is a melt method crystal growth method for growing emerald sapphire crystals by adopting the Czochralski method.

Drawings

FIG. 1 is an XRD test chart of emerald diamond crystals provided according to an embodiment of the invention;

FIG. 2 is a Laue diffraction pattern of an emerald gemstone crystal provided in accordance with an embodiment of the invention;

FIG. 3 is a view of an emerald sapphire crystal grown by a Czochralski method according to an embodiment of the invention;

fig. 4 is a graph of light extraction test results of an emerald crystal obtained by a method of growing an emerald crystal according to an embodiment of the present invention;

fig. 5 is a graph of light extraction test results of an emerald crystal obtained by a method of growing an emerald crystal according to an embodiment of the present invention;

Detailed Description

The present invention will be described in detail with reference to exemplary embodiments, and in order to more clearly describe the method for growing emerald sapphire crystals by the czochralski method provided in the embodiments of the present invention, the following description will be made with reference to the specific embodiments.

The embodiment provides a method for growing emerald diamond crystals by adopting a pulling method, which performs directional growth of seed crystals by the pulling method, and comprises the following steps:

inoculation: before inoculation, the seed crystal is rotated, the inoculation condition is observed in real time by using a ccd camera, and when inoculation is carried out, the weight curve change shown by the observation software is observed, the curve is a horizontal straight line, and pulling is started;

shouldering: in the shouldering process, the diameter d of the crystal grows to 50-70% of the diameter of the crucible from 5-10 mm step by step, and the diameter d of the crystal linearly changes along with the shouldering length L;

and (3) isometric growth: in the process of isometric growth, according to the quality change condition of the crystal growing in unit time, the PID algorithm is used for carrying out feedback control on the heating power, so that the active control of the crystal growing speed is realized, and the weight of the crystal is in accordance with the weight obtained by calculation of the design appearance;

ending: ending after the equal-diameter growth length reaches the design requirement, adjusting the power through PID in the ending process to ensure that the diameter of the crystal begins to be reduced, and ending the ending growth;

cooling: and cooling the crystal to room temperature to obtain the emerald crystal.

Wherein, the seed crystal is a cuboid seed crystal with a cross section of 5 multiplied by 5 to 10 multiplied by 10 mm.

Wherein, before inoculation, the seed crystal rotates at the speed of 2-20 rpm in the inoculation process; the pulling speed in the inoculation process is 0.2-2 mm/h.

The shoulder-putting method comprises the following specific steps:

pulling the crystal according to 0.2-2 mm/h until the diameter D of the crystal is 50-70% of the diameter D of the crucible, and controlling the length-diameter ratio and the diameter ratio of the crystal to be 1: 1, in the upward pulling process, the crystal rotates at the speed of 2-20 rpm;

and when the diameter of the crystal obtained in the step is larger than the length of the crystal by about 10-15 mm, controlling the crystal to start to have the same diameter.

Wherein the diameter d of the crystal satisfies 50mm < d <100mm, and the shouldering length L satisfies 50mm < L <70 mm.

In the embodiment, after the ending growth is finished, the diameter of the crystal is 60-80% of the diameter of the constant diameter, and the ending length is 40-60% of the shouldering length.

Wherein, the concrete step of cooling does:

after growth is finished, entering a cooling stage, stopping rotation, and reducing 500w in 20 minutes under the current power for finishing growth;

after the steps are finished, the power is reduced to 0 from the current power for 72-96 h at the speed of 200-300 w/h, and after the temperature reduction procedure is finished, the temperature of the crystal is reduced to the room temperature.

In this embodiment, in the method for growing emerald sapphire crystal by using the czochralski method, the crystal growth condition is observed in real time by using an infrared CCD camera in the whole crystal growth process.

The embodiment also provides an emerald crystal, which is prepared by the method for growing the emerald crystal by adopting the pulling method.

The process of growing an emerald crystal of phi 84mm by using the method for growing an emerald crystal by the czochralski method provided by the embodiment is as follows:

the seed crystal is grown by adopting an iridium crucible with the diameter of 150mm multiplied by 150mm and a JGD pulling single crystal furnace system of a middle power department 26, wherein the feeding weight of the raw material of the emerald diamond crystal is 5.8kg, and the seed crystal is a cuboid emerald diamond crystal with the direction of <001> and the size of 6mm multiplied by 80 mm.

After the raw materials are fully melted in a single crystal furnace, the temperature of the center of the melt is reduced to 1870 ℃, emerald gemstone crystal seeds are added into the melt, the emerald gemstone crystal seeds grow from 12mm in diameter at the speed of 1.6mm/h, the rotating speed is fixed at 18rpm, the crystal shouldering curve is 2ndhalfspline, the shouldering length is 70mm, the equal-diameter is set to 84mm, the equal-diameter length is set to 140mm, the ending diameter is set to 60mm, and the ending length is set to 30 mm. According to the shape design and the crystal density parameters, the unit growth speed is calculated through software, the PID algorithm is used for carrying out feedback control on the heating power, and the growth of the crystal is regulated and controlled, so that the crystal grows at the speed of 1.6mm/h in the whole growth process. The material melting time is 3-5 days, the growth time is 6.25 days, and the temperature reduction time is 7 days, namely, the growth of 3.8kg of emerald crystal with phi of 84mm can be completed in 18 days.

The crystal test results were as follows:

the crystal emits obvious red light by adopting 532nm laser for irradiation, and no obvious light path and scattering exist inside the crystal. The crystal is transparent and uniform under the observation of a stress meter, and no obvious stress distribution exists. As shown in fig. 1-2, conventional XRD and laue diffraction tests were performed on the crystals, where the XRD scans ranged from 10 ° to 80 °, with a step size of 0.02 °; the sample used in the Laue test diffraction is not oriented, and the spot diameter of the used diffraction beam is about 300 mu m.

XRD scanning shows that the crystal has only one characteristic peak in the scanning range of 10-80 deg. which corresponds to the characteristic peak of the parallel surface of the single crystal sample, but the full width at half maximum of the peak is wide, probably because the noise is too strong.

Clear diffraction spots in symmetrical arrangement can be seen from the Laue diffraction pattern, and the crystal can be preliminarily inferred to be a single crystal sample by combining XRD pattern information.

The emerald crystal grown by the method for growing the emerald crystal by the pulling method provided by the embodiment of the invention can perfectly control the crystal diameter in the growth process, and the appearance of the grown crystal is kept highly consistent with the designed appearance. As shown in figure 3, the size equal diameter part reaches phi 84 multiplied by 140mm, the utilization rate reaches more than 80 percent, and the large-size high-quality emerald crystal for commercial application is obtained.

The light extraction test results of the crystal rod using emerald precious stone provided by the embodiment of the invention are shown in fig. 4 and 5.

While the methods and techniques of the present invention have been described in terms of preferred embodiments, it will be apparent to those of ordinary skill in the art that variations and/or modifications of the methods and techniques described herein may be made without departing from the spirit and scope of the invention. It is expressly intended that all such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the spirit, scope and content of the invention.