CN108393042A - The synthesizer and its synthetic method of a kind of carat of grade diamond - Google Patents

Abstract

The invention discloses a carat grade diamond synthesis device and its synthesis method. First, a heating tube, a honeycomb module, a thermal insulation pressure transmission sheet, a heating sheet and a metal sheet are used to assemble a synthesis column, and then the synthesis column is put into the upper half The synthetic block is obtained in the pyrophyllite cavity formed by buckling the upper pyrophyllite cup body and the lower half pyrophyllite cup body; then the synthetic block is put into a six-sided top diamond press for synthesis, and carat-level diamonds are obtained. The synthesis device used in the preparation method provides a completely independent growth environment for the growth of each diamond, ensuring that the diamond can grow stably, efficiently and with high quality for a long time; the setting of through holes and conductive pillars in the pyrophyllite reduces heating power and saves electric energy , energy saving and emission reduction, also improves the uniformity of temperature in the synthesis chamber, and increases the synthesis of high-quality diamonds; the method vacuum-packs the synthesis column during the preparation process to effectively avoid oxidation and the increase of impurity nitrogen during the synthesis process.

Description

A kind of synthesis device and synthesis method of carat grade diamond

technical field

The invention belongs to the field of diamond synthesis, and in particular relates to a synthesis device and a synthesis method for carat-level diamonds.

technical background

Diamond is also called diamond. With the continuous advancement of science and technology, gem-quality diamonds have been widely used in ultra-precision machining of high-hardness materials, heat sinks for semiconductor lasers and high-power laser weapons, window materials in the aerospace field, optical materials and wide-bandgap semiconductor materials, etc., are playing an increasingly important role. At present, the demand for jewelry-grade diamonds in the market is also increasing, especially for carat-grade diamonds. Therefore, natural diamonds are far from meeting the needs of development. Therefore, various methods of artificially synthesizing diamonds have been developed in this field.

At present, the synthesis methods of diamonds are mainly based on CVD and temperature difference method. However, due to the influence of CVD’s growth principle, the thickness of carbon atom deposition is relatively thin, and most of them are in the form of flakes. Moreover, only one or A few less, longer synthesis cycle, higher cost and difficult to control the crystal form. The artificial synthesis technology of gem-grade diamonds by the temperature difference method is quite mature, and this method can produce carat-grade artificial diamonds. At present, the cavity structure adopted by the temperature difference method mainly adopts the upper and lower indirect heating method, and the temperature difference mainly depends on the carbon source in the high temperature zone being transported to the surface of the seed crystal in the low temperature zone through the molten catalyst, so that it grows; but due to the heating method Influenced by the method of assembly and assembly, the up and down direction, the temperature is high and the bottom is low, and the left and right directions are high outside and low inside. Therefore, it is easy to cause a large difference in radial and longitudinal temperature differences during the diamond growth process, resulting in the deposition rate of carbon sources at different positions and The content of carbon is different, resulting in different sizes of synthetic diamonds; in addition, the lateral temperature difference in the left and right directions is also easy to cause segregation of carbon sources, making the shape of synthetic diamonds poor.

For carat-level diamonds that have been synthesized for a long time, the above-mentioned problems make the defects of synthetic diamonds more obvious, greatly reducing the quality of carat-level diamonds produced, making it difficult to achieve stable production of carat-level diamonds, and high-quality products cannot be obtained. , which reduces the overall production efficiency and the output rate is low.

Contents of the invention

In order to solve the problems referred to above, the present invention provides a kind of synthetic device of carat grade diamond, and this device is provided with a plurality of separate chambers in the synthetic column of carat grade diamond, and each chamber is used for the growth of single carat grade diamond, Give each diamond a stable and rich growth carbon source and catalyst in a single-chamber manner, that is, each diamond has a stable and independent growth environment and a suitable growth space, so that the diamond can grow with high quality and efficiency;

The present invention also provides a synthetic method for artificially synthesizing carat-grade diamonds by using the above-mentioned device, and the method obviously improves the transparency and color grade of the synthetic diamonds.

The present invention is achieved through the following technical solutions

A synthesis device for carat grade diamonds, the device comprises a pyrophyllite cavity and a synthesis column arranged in the pyrophyllite cavity; the pyrophyllite cavity is formed by fastening the upper body of the pyrophyllite cup and the lower half of the pyrophyllite cup. The cup bottom of the above-mentioned upper half pyrophyllite cup body and the cup bottom of the lower half pyrophyllite cup body are all provided with a plurality of pyrophyllite through holes, and a conductive column is provided in the described pyrophyllite through hole; the synthesis column includes a heating tube (both ends Open hollow circular pipe sleeve) and the diamond growth module and the heat preservation pressure transmission sheet (the crystal bed, the catalyst sheet and the carbon source are sequentially arranged in the diamond growth module from bottom to top) in the heating tube; the synthesis column also includes The heating sheet and the metal sheet are stacked at the upper end of the heating tube, and the heating sheet and the metal sheet are stacked at the lower end of the heating tube; the heating sheet is connected to the heating tube, and the metal sheet is connected to one end of the conductive column located inside the pyrophyllite cavity.

In the carat-grade diamond synthesis device, the upper half of the pyrophyllite cup is consistent with the lower half of the pyrophyllite cup; the inner walls of the upper and lower pyrophyllite cups are both open at one end Hollow cylinder, the outer wall of which is a hollow cuboid with one end open; the diameter of the pyrophyllite through hole arranged at the bottom of the pyrophyllite cup is 4-6mm; the length of the conductive column is consistent with the length of the pyrophyllite through hole, and the diameter of the conductive column Consistent with the diameter of pyrophyllite vias.

In the carat-grade diamond synthesis device, the diamond growth module is a honeycomb module; the heat preservation and pressure transmission sheet is the first heat preservation and pressure transmission sheet or the first heat insulation and pressure transmission sheet and the second heat insulation and pressure transmission sheet.

In the carat-grade diamond synthesis device, the honeycomb module includes a module body and a plurality of blind holes arranged longitudinally on the upper part of the module body, and honeycomb holes with blind holes are sequentially stacked in the heating tube from bottom to top. module, the first thermal insulation pressure transmission sheet; the sum of the heights of the honeycomb module with blind holes and the first thermal insulation pressure transmission sheet is equal to the height of the heating tube; the honeycomb module is provided with a plurality of blind holes at intervals, The interval between blind holes is 2-4mm, the diameter of each blind hole is 6-15mm, and the depth of blind holes is 15-25mm; each blind hole is sequentially provided with crystals from bottom to top. Bed, catalyst sheet and carbon source, the sum of the height of described crystal bed, catalyst sheet and carbon source equals the depth of blind hole; The thickness (being the height of the first heat preservation pressure transmission sheet) of described first insulation transmission sheet is 20-30 mm, and the thickness of the crystal bed is 3-8 mm.

In the carat-grade diamond synthesis device, the honeycomb module includes a module body and a plurality of through holes arranged longitudinally along the module body, and the heating tube is sequentially provided with a second thermal insulation and pressure transmission sheet, with a through hole. Hole honeycomb module, the first thermal insulation pressure transmission sheet; the sum of the heights of the second thermal insulation pressure transmission sheet, the honeycomb module and the first thermal insulation pressure transmission sheet is equal to the height of the heating tube; the honeycomb module is arranged at intervals There are multiple through holes, the interval between the through holes is 2-4mm, the diameter of the through-holes is 6-15mm, and the length of the through-holes is 15-25mm; each through-hole is composed of the following A crystal bed, a catalyst sheet and a carbon source are arranged in sequence upwards, and the sum of the heights of the crystal bed, the catalyst sheet and the carbon source is equal to the height of the honeycomb module (that is, equal to the length of the through hole on the honeycomb module body); the second The thickness of the second thermal insulation and pressure transfer sheet is 1/3 to 1/4 of the thickness of the first thermal insulation and pressure transfer sheet.

In the carat-grade diamond synthesis device, the diameters of the heating sheet and the metal sheet are equal to the outer diameter of the heating tube; the thickness of the heating sheet is 1-4 mm, and the thickness of the metal sheet is 0.5-1 mm.

A method for synthesizing carat-level diamonds using the synthetic device of the above-mentioned carat-level diamonds, the method may further comprise the steps:

(1) Prepare the diamond growth module, the first thermal insulation transmission sheet, the second thermal insulation transmission compression sheet, the crystal bed, the catalyst sheet, the carbon source, and prepare the heating tube, the heating sheet, and the metal sheet;

(2) The diamond growth module, the first thermal insulation and pressure transmission sheet or the first thermal insulation and pressure transmission sheet and the second insulation and pressure transmission sheet, crystal bed, carbon source, catalyst sheet, and heating tube, heating sheet and metal sheet are used to assemble a synthetic column, and preserved in vacuum packaging, for standby;

(3) Prepare the upper half pyrophyllite cup with through holes at the bottom of the cup and the lower half pyrophyllite cup with holes at the bottom of the cup, then bake the perforated pyrophyllite shell. 60-80 insulation);

(4) the synthetic column that step (2) is obtained is put into the second half pyrophyllite cup of step (3) described insulated (firstly synthetic column is removed vacuum packing, then puts into the lower half pyrophyllite cup immediately), then Cover the upper half of the pyrophyllite cup, that is, buckle with the lower half of the pyrophyllite cup to form a pyrophyllite cavity, and then insert the conductive pillars into the through holes at the bottom of the upper half of the pyrophyllite cup and the through holes at the bottom of the lower half of the pyrophyllite cup. In the hole, after the insertion is completed, a synthetic block of single-chamber single-grain synthetic carat diamond is obtained;

(5) The synthetic block obtained in step (4) is baked and dehumidified. After the dehumidification is completed, it is put into a six-sided top diamond synthesis press for synthesis. After the synthesis is completed, a carat-grade synthetic diamond is obtained.

In the method for synthesizing carat-grade diamonds, the synthesis column described in step (2) is to place the diamond growth module and the first thermal insulation and pressure transmission sheet sequentially in the heating tube from bottom to top, and stack heating sheets and metal sheets at the upper end of the heating tube , and the lower end of the heating tube is stacked with a heating sheet and a metal sheet;

Wherein the diamond growth module is a honeycomb module, and the honeycomb module includes a module body and a plurality of blind holes arranged longitudinally on the upper part of the module body, and all blind holes of the honeycomb module are sequentially placed with a crystal bed and a catalyst flakes and carbon source.

In the method for synthesizing carat-grade diamonds, the synthesis column in step (2) is to sequentially place the second thermal insulation and pressure transmission sheet, the diamond growth module, and the first thermal insulation and pressure transmission sheet in the heating tube from bottom to top, and stack them on the upper end of the heating tube Setting the heating sheet and the metal sheet, and stacking the heating sheet and the metal sheet at the lower end of the heating tube;

Wherein, the diamond growth module is a honeycomb module, and the honeycomb module includes a module body and a plurality of through holes arranged longitudinally along the module body, and all the through holes of the honeycomb module are sequentially placed crystal beds, Catalyst sheets and carbon sources.

In the method for synthesizing carat-grade diamonds, the heating sheet is a sheet-like structure cut from a high-purity graphite rod;

Both the first thermal insulation and pressure transmission sheet and the second thermal insulation and pressure transmission sheet are cylinders pressed by high-purity magnesium oxide; the honeycomb module is composed of magnesia with a mass content of 80% and a mass content of 20% A perforated cylinder made of mixed zirconia;

The crystal bed is a cylinder pressed by high-purity magnesium oxide, and the catalyst sheet is formed by mixing and pressing Fe with a mass content of 50-70%, Ni with a mass content of 30-50%, and trace elements. The trace elements are 0.1-1% of Ti, 0.5-1.5% of Si and 0.1-0.5% of Ce, accounting for the total mass of the above elements.

In the method for synthesizing carat-grade diamonds, the baking and roasting of the pyrophyllite shell in step (4) is specifically baking and roasting at 280-300°C for 36 hours, and cooling to 60-80°C after the baking and roasting is completed. Heat preservation at ~80°C for standby; step (5) to bake and dehumidify the synthetic block is specifically to bake at 100-130°C for 8 hours, and put it directly into the six-sided top diamond synthesis press after the baking is completed .

The method for synthesizing carat-grade diamonds, when the synthetic block described in step (5) is synthesized in a six-sided top diamond synthetic press, is specifically: the pressure of the six-sided top synthetic press is boosted to 90-90 ~ 100MPa, at the same time, the temperature is raised to 1300-1400°C within 30-60 minutes, and then synthesized under the pressure and temperature conditions for 100-300 hours. After the synthesis is completed, the press is simultaneously released and cooled. Complete the depressurization and cooling of the press (that is, the temperature in the press is cooled to room temperature and the pressure is reduced to normal pressure within 1 to 2 hours), and the carat-grade synthetic diamond is obtained.

Compared with the prior art, the present invention has the following positive beneficial effects

The synthesis block of the present invention is provided with a honeycomb module, and the single chamber provided in the module provides a completely independent growth environment for the growth of each diamond, effectively ensuring the uniform and sufficient supply of each diamond growth carbon source in the synthesis cavity, and avoiding In the synthesis process, the phenomenon of large temperature difference caused by the deformation of the catalyst is effectively solved, which effectively solves the problem that the temperature difference of the catalyst in different regions increases with time during the synthesis process, and ensures that the diamond can be stable and efficient for a long time , high-quality production;

Moreover, under an independent growth environment, since the temperature field in each diamond growth chamber is uniform, the directional supply of the carbon source to the seed crystal is more uniform and sufficient, so at the same time, the growth rate of the diamond in the structure of the present invention has increased by more than 20%. , that is, the structure can grow high-quality diamonds in a relatively short period of time, with good quality and good economic benefits;

The pyrophyllite used in the present invention has a porous pyrophyllite structure, and conductive columns are arranged in the cavity, which reduces the heat dissipation at both ends of the pyrophyllite and further ensures the uniformity of the temperature field; There are through holes at the bottom, and conductive posts are arranged in the through holes. This structure increases the temperature at the end and reduces heat loss. The uniformity of temperature in the body, which improves the synthesis of high-quality diamonds;

The diamond synthesis device described in the present invention is simple in structure and easy to assemble, provides a completely independent growth environment for the growth of each diamond, has high stability and strong repeatability, and the excellent crystal rate of carat-grade diamonds synthesized by the device reaches 90%. Above; and the growth time is short, the production efficiency is high, the cost is low, and energy is saved, which can better realize the large-scale green production of carat-level diamonds, and has good social and economic benefits;

The carat grade diamond synthesized by the single particle growth device and method of the present invention has uniform particle size and regular shape, which effectively solves the problem of low diamond grinding utilization rate caused by the asymmetric growth of existing diamonds;

In the production process of the present invention, the synthetic column is vacuum-encapsulated, which effectively avoids the occurrence of oxidation, reduces the nitrogen content, and improves the transparency and color grade of the synthetic diamond. Most of the finally obtained diamonds are uniform. Reach the E level.

Description of drawings

Figure 1 is one of the longitudinal sections of the pyrophyllite cavity of the carat-level diamond synthesis device,

Figure 2 is a structural schematic diagram of a carat-level diamond synthesis column,

Figure 3 is one of the longitudinal sectional views of the carat-level diamond synthesis device,

Figure 3-1 is an enlarged view of the longitudinal section of the blind hole in Figure 3,

Fig. 3-2 is a structural diagram of the diamond growth module and the thermal insulation and pressure transmission sheet placed in the heating tube of the carat-level diamond synthesis device described in Fig. 3;

Figure 4 is the second longitudinal section view of the carat-level diamond synthesis device,

Figure 5 is one of the longitudinal sectional views of the honeycomb module,

Fig. 6 is the second longitudinal sectional view of the honeycomb module,

Figure 7 is a top view of the honeycomb module,

Figure 8 is the second longitudinal section of the pyrophyllite cavity of the carat-level diamond synthesis device,

Fig. 9 is a longitudinal sectional view of a pyrophyllite cup body,

The meanings of the symbols in the figure are: 1 represents the pyrophyllite cavity, 2 represents the upper half of the pyrophyllite cup, 3 represents the lower half of the pyrophyllite cup, 4 represents the synthesis column, 5 represents the heating tube, and 601 represents the honeycomb with blind holes 602 represents the honeycomb module with through holes, 7 represents the first thermal insulation and pressure transmission sheet, 8 represents the heating sheet, 9 represents the metal sheet, 10 represents the pyrophyllite through hole, 11 represents the conductive column, 12 represents the second thermal insulation transmission Pressed tablet; 6011 indicates the blind hole in the honeycomb module, 6012 indicates the crystal bed in the blind hole of the honeycomb module, 6013 indicates the catalyst sheet in the blind hole of the honeycomb module, 6014 indicates the carbon source in the blind hole of the honeycomb module, 6021 indicates the honeycomb module In the through hole, 6022 represents the crystal bed in the through hole of the honeycomb module, 6023 represents the catalyst sheet in the through hole of the honeycomb module, and 6024 represents the carbon source in the through hole of the honeycomb module.

Detailed ways

The present invention will be described in more detail through specific embodiments below, but it is not intended to limit the protection scope of the present invention.

Example 1

A device for artificially synthesizing carat-grade diamonds, as shown in Figure 1, Figure 2, Figure 3, Figure 3-1, and Figure 3-2, the device includes a pyrophyllite cavity 1, and the pyrophyllite cavity 1 consists of an upper half The upper pyrophyllite cup body 2 and the lower half pyrophyllite cup body 3 are fastened together, and the cup bottoms of the upper half pyrophyllite cup body 2 and the lower half pyrophyllite cup body 3 are all provided with a plurality of pyrophyllite through holes 10. The diameter of through hole is 4～6mm, is provided with conductive post 11 in the through hole, and the diameter and the length of described conductive post 11 are all consistent with the diameter and the length of pyrophyllite through hole 10 (the cup bottom thickness of pyrophyllite cup body is 10～6mm. 15mm, that is, the length of the pyrophyllite through hole is 10-15mm, and the wall thickness of the pyrophyllite cup is 8～9mm); the device also includes a synthesis column 4 arranged in the pyrophyllite cavity 1, and the synthesis column 4 includes a heating tube 5 and the honeycomb module 601 with blind holes and the first thermal insulation pressure transmission sheet 7 arranged sequentially from bottom to top in the heating pipe 5, the honeycomb module 601 with blind holes and the first thermal insulation pressure transmission sheet 7 The diameters of the honeycomb modules 601 with blind holes and the height of the first thermal insulation pressure transmission sheet 7 are equal to the height of the heating pipe 5; The heating sheet 8 connected to the pipe, and the metal sheet 9 that is close to the heating sheet 8 and stacked with the heating sheet 8; the one end of the conductive column 11 located inside the pyrophyllite cavity 1 is connected to the metal sheet 9 .

As shown in Figures 5 and 7, the honeycomb module with blind holes includes a module body and a plurality of blind holes 6011 arranged at intervals along the longitudinal direction of the module body on the upper part of the module body, and the interval between blind holes is 2 ~4mm; the diameter of the blind hole 6011 is 6~15mm (change the diameter according to the size of the prepared diamond, the blind holes on the same module body can be blind holes with different diameters, that is, the same module can prepare diamond particles of different sizes ), the depth of the blind hole is 15-25mm, and the crystal bed 6012, the catalyst sheet 6013 and the carbon source 6014 are stacked sequentially from bottom to top in the blind hole, wherein the sum of the heights of the crystal bed 6012, the catalyst sheet 6013 and the carbon source 6014 is equal to The depth of the blind hole 6011 and the thickness of the crystal bed 6012 are 3-8mm.

Further, the thickness of the heating sheet is 1-4 mm, the thickness of the metal sheet is 0.5-1 mm; the thickness of the first thermal insulation and pressure transmission sheet is 20-30 mm.

Further, as shown in Figures 8 and 9, the upper half of the pyrophyllite cup body is the same as the lower half of the pyrophyllite cup body, the interior of the cup body is a hollow cylinder with one end open, and the outer surface of the cup body is an open end hollow cuboid.

Example 2

The same parts in embodiment 2 and embodiment 1 have the same functions, and for the sake of brevity, they will not be repeated.

A synthetic device for carat-level diamonds, as shown in Figure 4, the second thermal insulation heating sheet 12, the honeycomb module 602 with through holes, the first thermal insulation and pressure transmission sheet are stacked sequentially from bottom to top in the heating tube 7. The sum of the heights of the second thermal insulation and pressure transmission sheet 12, the honeycomb module 602 with through holes and the first thermal insulation and pressure transmission sheet 7 is equal to the height of the heating pipe 5;

As shown in Figure 6, the honeycomb module 602 with through holes includes a module body and a plurality of through holes 6021 arranged at intervals along the longitudinal direction of the module body, and the interval between the through holes is 2-4mm; the diameter of the through holes 6021 Both are 6-15m (the diameter can be changed according to the size of the prepared diamonds, the blind holes on the same module body can be blind holes with different diameters, that is, the same module can prepare diamond particles of different sizes), and the length of the through holes is uniform. 15-25mm (also referring to the depth of the through hole), the through hole 6021 is provided with a crystal bed 6022, a catalyst sheet 6023 and a carbon source 6024 in sequence from bottom to top, and the height of the crystal bed 6022, catalyst sheet 6023 and carbon source 6024 is The sum is equal to the height of the through-hole honeycomb module 602 (that is, equal to the length of the through hole on the honeycomb module); the thickness of the crystal bed 6022 is 3-8mm.

Further, the thickness of the first thermal insulation and pressure transmitting sheet is 20-30 mm; the thickness of the second thermal insulation and pressure transmitting sheet is 1/3 to 1/4 of the thickness of the first thermal insulation and pressure transmitting sheet.

When using this structure to synthesize carat-level diamonds, the holes set on the honeycomb module provide a completely independent growth environment for the growth of each diamond, and there is no difference caused by the temperature of the catalyst over time. The uniform supply of the source ensures the consistency of diamond growth and the stable growth of diamonds. The quality of the diamond is guaranteed, so that the diamond can grow with high quality and high efficiency. In this device, the through hole at the bottom of the pyrophyllite shell and the internal conductive column structure reduce the heat dissipation at both ends of the pyrophyllite, further effectively ensure the uniform temperature field, and further ensure the efficient growth of diamonds and the quality of diamonds.

Example 3

In this embodiment, the heating sheet is a sheet structure (the diameter of which is the same as the outer diameter of the heating tube) cut from a high-purity graphite rod by a common method.

Both the first thermal insulation and pressure transmission sheet and the second thermal insulation and pressure transmission sheet are cylinders pressed by high-purity magnesium oxide; the honeycomb module is composed of magnesia with a mass content of 80% and a mass content of 20% A cylinder with a hole (the hole is a blind hole or a through hole from the upper part downward along the longitudinal direction of the cylinder) made of zirconia mixed and pressed by common methods;

The crystal bed is a cylinder formed by pressing high-purity magnesium oxide by a common method, and the catalyst sheet is composed of Fe with a mass content of 50-70% and Ni with a mass content of 30-50% and trace elements commonly used The method is made by mixing and pressing, and the trace elements are 0.1-1% of Ti, 0.5-1.5% of Si and 0.1-0.5% of Ce accounting for the total mass of the above elements.

One of the methods for the synthesis of carat-level diamonds using the above-mentioned device for artificially synthesizing carat-level diamonds, the method may further comprise the steps:

(1) Prepare the honeycomb module with blind holes, the first thermal insulation pressure transmission sheet, crystal bed, catalyst sheet and carbon source, and heating tube, heating sheet and metal sheet (iron sheet);

(2) Use the materials prepared in step (1) to assemble the synthetic column:

First place the crystal bed (6mm in thickness), the catalyst sheet (6mm in thickness) and the carbon source (6mm in thickness) from bottom to top in the blind holes of the honeycomb module with blind holes; The heat preservation and pressure transmission sheet (thickness is 25mm) is placed on the honeycomb module (thickness is 21mm), and then placed in the heating tube (the height of the heating tube is 46mm and the outer diameter is 48mm) according to the above sequence; Place heating sheets (thickness: 1.5mm) whose diameter is equal to the outer diameter of the heating pipe at the upper and lower ends of the tube, and then place iron sheets (thickness: 0.5mm) on the heating sheets at the upper and lower ends respectively, that is, assemble into a synthetic column, The synthesis column is vacuum-packaged and stored for later use;

(3) Pyrophyllite cavity

Prepare the upper half of the pyrophyllite cup body with 3 through holes at the bottom of the cup and the lower half of the pyrophyllite cup body with 3 through holes at the bottom of the cup (the size of the two pyrophyllite cup bodies is 70*ф54), and put the two pyrophyllite The cup is baked and roasted at 280-300°C for 36 hours, and then cooled to 60-80°C after baking and roasting, and then kept at this temperature for later use;

(4) Assembly of synthetic blocks

Remove the vacuum packaging of the synthetic column obtained in step (2), put it into the lower half of the pyrophyllite cup under the heat preservation state immediately, then cover the upper half of the pyrophyllite cup, and buckle with the lower half of the pyrophyllite cup to form a pyrophyllite cavity. After the fastening is completed, insert the matching conductive post into the through hole at the bottom of the upper pyrophyllite cup and the through hole at the bottom of the bottom half of the pyrophyllite cup. The end of the conductive post located in the pyrophyllite cavity is connected to the iron sheet ; That is, get the composite block;

(5) Synthesis of diamonds

Dehumidify the synthetic block obtained in step (4) at 100-130°C for 8 hours. After the dehumidification is completed, put it into the six-sided top diamond synthesis press; then start the press, and its pressure will increase to 90 within 1-2 minutes ～100MPa, at the same time, the temperature is raised to 1300～1400°C within 30～60min, and then synthesized under this condition for 120 hours; Under normal pressure, cool down to room temperature; then break open the synthetic block, take out the synthetic column, and remove the metal and graphite through acid-base purification to obtain a single 1-3 carat diamond. After testing, the color can reach D and E grades, and the clarity can reach VS grades.

Example 4

In this embodiment, the heating sheet is a sheet structure (the diameter of which is the same as the outer diameter of the heating tube) cut from a high-purity graphite rod by a common method.

Both the first thermal insulation and pressure transmission sheet and the second thermal insulation and pressure transmission sheet are cylinders pressed by high-purity magnesium oxide; the honeycomb module is composed of magnesia with a mass content of 80% and a mass content of 20% The zirconia is a perforated cylinder formed by mixing and pressing by common methods;

The crystal bed is a cylinder formed by pressing high-purity magnesium oxide by a common method, and the catalyst sheet is composed of Fe with a mass content of 50-70% and Ni with a mass content of 30-50% and trace elements commonly used The method is made by mixing and pressing, and the trace elements are 0.1-1% of Ti, 0.5-1.5% of Si and 0.1-0.5% of Ce accounting for the total mass of the above elements.

The second method of using the above-mentioned synthetic carat-grade diamond device to synthesize carat-grade diamonds, the method comprises the following steps:

(1) Prepare a honeycomb module with through holes, the first thermal insulation pressure transmission sheet, the second thermal insulation pressure transmission sheet, crystal bed, catalyst sheet and carbon source, and heating tube, heating sheet and metal sheet (copper sheet);

(2) Use the materials prepared in step (1) to assemble the synthetic column:

First, the honeycomb module with through holes is placed on the second thermal insulation pressure transmission sheet (thickness is 5mm), and then the crystal bed (thickness is 3mm) is placed in the through holes of the honeycomb module with through holes from bottom to top. ), the catalyst sheet (the thickness is 7mm) and the carbon source (the thickness is 8mm); Then place it in the heating tube according to the above sequence (the thickness of the heating tube is 43mm and the outer diameter is 50mm); 2mm), and then place copper sheets (thickness 1mm) on the heating sheets at the upper and lower ends respectively, that is, assemble into a synthetic column, vacuum-pack the synthetic column, and save it for later use;

(3) Pyrophyllite cavity

Prepare the upper half of the pyrophyllite cup body with 4 through holes at the bottom of the cup and the lower half of the pyrophyllite cup body with 4 through holes at the bottom of the cup (the size of the two pyrophyllite cup bodies is equal, both are 72*ф56), put The two pyrophyllite cups are baked and roasted at 280-300°C for 36 hours, and then cooled to 60-80°C after the baking and roasting, and then kept at this temperature for later use;

(4) Assembly of synthetic blocks

Remove the vacuum packaging of the synthetic column obtained in step (2), put it into the lower half of the pyrophyllite cup under the heat preservation state immediately, then cover the upper half of the pyrophyllite cup, and buckle with the lower half of the pyrophyllite cup to form a pyrophyllite cavity. After the fastening is completed, insert the matching conductive post into the through hole at the bottom of the upper pyrophyllite cup and the through hole at the bottom of the bottom half of the pyrophyllite cup. The end of the conductive post located in the pyrophyllite cavity is connected to the copper sheet ; That is, get the composite block;

(5) Synthesis of diamonds

Dehumidify the synthetic block obtained in step (4) at 100-130°C for 8 hours. After the dehumidification is completed, put it into the six-sided top diamond synthesis press; then start the press, and its pressure will increase to 90 within 1-2 minutes ~100MPa, at the same time, the temperature is raised to 1300~1400°C within 30~60min, and then synthesized under this condition for 200 hours; Atmospheric pressure, cool down to room temperature; cool down to room temperature; then break open the synthetic block, take out the synthetic column, and remove the metal and graphite through acid-base purification to obtain a single 2-4 carat diamond. After testing, the color can reach D and E grades, and the clarity can reach VS grades.

Claims (10)

1. a synthetic device for carat grade diamonds, the device comprises a pyrophyllite cavity and a synthetic post arranged in the pyrophyllite cavity, characterized in that, the pyrophyllite cavity consists of an upper half pyrophyllite cup body and a lower half pyrophyllite cup The cup bottom of the upper half of the pyrophyllite cup body and the cup bottom of the lower half of the pyrophyllite cup body are all provided with a plurality of pyrophyllite through holes, and conductive columns are arranged in the pyrophyllite through holes; The synthesis column includes a heating tube, and the heating tube is a hollow circular tube sleeve with openings at both ends, and a diamond growth module and a thermal insulation pressure transmission sheet are stacked in the heating tube; the synthesis column also includes a heating sheet stacked on the upper end of the heating tube and the metal sheet, and the heating sheet and the metal sheet stacked at the lower end of the heating tube; the heating sheet is connected to the heating tube, and the metal sheet is connected to one end of the conductive column located inside the pyrophyllite cavity. 2. the synthetic device of carat grade diamond according to claim 1, is characterized in that, described upper half pyrophyllite cup body is consistent with lower half pyrophyllite cup body; Described upper half pyrophyllite cup body and lower half The inner surface of the pyrophyllite cup is a hollow cylinder with one end open, and the outer surface is a hollow cuboid with one end open; the diameter of the through hole at the bottom of the pyrophyllite cup is 4-6mm; the length of the conductive column is the same as that of the pyrophyllite. The length of the through hole is consistent, the diameter of the conductive column is consistent with the diameter of the pyrophyllite through hole; the diameters of the heating sheet and the metal sheet are equal to the outer diameter of the heating tube, the thickness of the heating sheet is 1-4mm, and the metal The thickness of the sheet is 0.5 to 1 mm. 3. according to claim 1 and the synthetic device of carat level diamond described in 2, it is characterized in that, described diamond growth module is to be provided with the honeycomb module of blind hole, and described thermal insulation transmission sheet is the first thermal insulation transmission sheet. Pressing sheet; the honeycomb module provided with blind holes includes a module body and a plurality of blind holes arranged longitudinally on the upper part of the module body, and the honeycomb module and the first thermal insulation pressure transmission sheet are sequentially stacked in the heating tube from bottom to top , the sum of the heights of the honeycomb module and the first thermal insulation pressure transmission sheet is equal to the height of the heating pipe; the honeycomb module is provided with a plurality of blind holes at intervals, and the intervals between the blind holes are 2 to 4mm. The diameter of the hole is 6-15mm, and the depth of the blind hole is 15-25mm. Each blind hole is provided with a crystal bed, a catalyst sheet and a carbon source in sequence from bottom to top. The sum of the heights is equal to the depth of the blind hole; the thickness of the first thermal insulation and pressure transmission sheet is 20-30mm, and the thickness of the crystal bed is 3-8mm. 4. according to the synthetic device of claim 1 or 2 described carat grade diamonds, it is characterized in that, described diamond growth module is the honeycomb module that is provided with through hole, and described heat preservation transmission sheet comprises the first heat preservation transmission Pressing sheet and second thermal insulation transmission sheet; the honeycomb module provided with through holes includes a module body and a plurality of through holes arranged longitudinally along the module body, and the second thermal insulation transmission sheet is sequentially stacked in the heating tube from bottom to top. Pressing sheet, honeycomb module, the first thermal insulation pressure transmission sheet; the sum of the heights of the second thermal insulation pressure transmission sheet, the honeycomb module and the first thermal insulation pressure transmission sheet is equal to the height of the heating tube; the interval between the honeycomb module There are a plurality of through holes, the diameter of the through holes is 6-15mm, the length of the through holes is 15-25mm, the interval between the through holes is 2-4mm, and each through hole is sequentially arranged from bottom to top. A crystal bed, a catalyst sheet, and a carbon source are provided, and the sum of the heights of the crystal bed, the catalyst sheet, and the carbon source is equal to the height of the honeycomb module; the thickness of the first thermal insulation sheet is 20-30 mm, and the The thickness of the second thermal insulation and pressure transfer sheet is 1/3 to 1/4 of the thickness of the first thermal insulation and pressure transfer sheet, and the thickness of the crystal bed is 3 to 8 mm. 5. a method for synthesizing carat-level diamonds using the carat-level diamond synthetic device claimed in claim 1, is characterized in that the method may further comprise the steps: (1) Prepare the diamond growth module, the first thermal insulation transmission sheet, the second thermal insulation transmission compression sheet, the crystal bed, the catalyst sheet, the carbon source, and prepare the heating tube, the heating sheet, and the metal sheet; (2) Adopt the diamond growth module prepared in step (1), the first thermal insulation pressure transmission sheet or the first thermal insulation pressure transmission sheet and the second thermal insulation pressure transmission sheet, crystal bed, carbon source, catalyst sheet, and heating tube, heating sheet Assemble with metal sheets to form a composite column, and store it in vacuum packaging for future use; (3) Prepare the upper half pyrophyllite cup and the lower half pyrophyllite cup with through holes at the bottom of the cup, then bake and roast, after the baking and roasting is completed, keep warm for standby; (4) Put the synthetic column obtained in step (2) into the spare lower half pyrophyllite cup described in step (3), then cover the upper half pyrophyllite cup, that is, snap together with the lower half pyrophyllite cup to form a pyrophyllite cavity body, and then insert the conductive posts into the through holes at the bottom of the upper pyrophyllite cup and the through holes at the bottom of the lower half of the pyrophyllite cup respectively. After the insertion is completed, a synthetic block of synthetic carat-level diamonds is obtained; (5) The synthetic block obtained in step (4) is baked and dehumidified. After the dehumidification is completed, it is put into a six-sided top diamond synthesis press for synthesis. After the synthesis is completed, a carat-level synthetic diamond can be obtained. 6. according to the method for the described synthetic carat grade diamond of claim 5, it is characterized in that, the synthetic column described in step (2) is to place diamond growth module, the first heat preservation transmission pressure sheet successively in heating tube from bottom to top, and A heating sheet and a metal sheet are stacked at the upper end of the heating tube, and a heating sheet and a metal sheet are stacked at the lower end of the heating tube; Wherein the diamond growth module is a honeycomb module, and the honeycomb module includes a module body and a plurality of blind holes arranged longitudinally on the upper part of the module body, and crystal beds are placed in all blind holes of the honeycomb module sequentially from bottom to top , catalyst sheet and carbon source. 7. according to the method for the described synthetic carat grade diamond of claim 5, it is characterized in that, the described synthesis post of step (2) is that the second thermal insulation transmission sheet, the diamond growth module, the first Insulation and pressure transmission sheet, and the heating sheet and the metal sheet are stacked on the upper end of the heating tube, and the heating sheet and the metal sheet are stacked on the lower end of the heating tube; Wherein, the diamond growth module is a honeycomb module, and the honeycomb module includes a module body and a plurality of through holes arranged longitudinally along the module body, and all through holes of the honeycomb module are sequentially placed crystal beds, Catalyst sheets and carbon sources. 8. according to the method for the described synthetic carat class diamond of claim 6 or 7, it is characterized in that, The heating sheet is a sheet structure cut from a high-purity graphite rod; Both the first thermal insulation and pressure transmission sheet and the second thermal insulation and pressure transmission sheet are cylinders pressed by high-purity magnesium oxide; the honeycomb module is composed of magnesia with a mass content of 80% and a mass content of 20% A perforated cylinder made of mixed zirconia; The crystal bed is a cylinder formed by pressing high-purity magnesium oxide, and the catalyst sheet is formed by mixing and pressing Fe with a mass content of 50-70%, Ni with a mass content of 30-50%, and trace elements. The trace elements are 0.1-1% of Ti, 0.5-1.5% of Si and 0.1-0.5% of Ce, accounting for the total mass of the above elements. 9. The method for synthesizing carat-grade diamonds according to claim 5, characterized in that the baking and roasting of the upper half of the pyrophyllite cup and the lower half of the pyrophyllite cup in step (3) is specifically baking at 280-300°C Baking and roasting for 36 hours, after the baking and roasting is completed, cool down to 60-80°C, and keep warm at 60-80°C for standby; in step (5), the synthetic block is baked and dehumidified at 100-130°C. Bake for 8 hours, and put it into the six-sided top diamond synthesis press after the baking is completed. 10. The method for synthesizing carat-level diamonds according to claim 5 is characterized in that, when the synthetic block described in step (6) is synthesized in the six-sided top diamond synthetic press, it is specifically: the pressure of the six-sided top synthetic press Boost the pressure to 90-100MPa within 1-2min, and at the same time, raise the temperature to 1300-1400℃ within 30-60min, and then synthesize under the pressure and temperature conditions for 100-300 hours. After the synthesis is completed, unload the press at the same time. Pressing and cooling, and completing the pressure relief and cooling of the press within 1 to 2 hours, that is, to obtain carat-level synthetic diamonds.