Large monocrystal diamond with (111) crystal face and preparation method thereof

Abstract

The invention discloses a (111) crystal face large single crystal diamond and a preparation method thereof, and the preparation method comprises the following steps: preparing alloy powder raw materials according to a mass ratio, and preparing alloy powder by using a water mist method; melting the alloy powder into a bar and cutting the bar into catalyst sheets; taking a magnesium oxide sheet with a seed crystal accommodating hole punched by a carving machine as a crystal bed; assembling according to a specific structure; and performing high-temperature and high-pressure synthesis in a cubic press according to a temperature and pressure curve. The diamond prepared through the method is good in quality, the proportion of the (1, 1, 1) crystal face is maximum, the diamond can be applied to cutting of the (111)-face diamond single crystal wafer, and economic benefits are good.

Description

Technical Field

[0001] The present invention relates to the technical field of diamonds, and in particular to a (111) crystal plane large single crystal diamond and a preparation method thereof. Background Art

[0002] The synthesis of artificial diamond is usually carried out by a six-sided top press under high temperature and high pressure, and the process of converting graphite into diamond through the action of a catalyst. At present, diamond single crystals are all (100) faces, while special application fields require large-sized diamond single crystals with (111) faces, which have strict requirements on the crystal shape and quality of large single crystals. At present, the relevant technology in China is relatively scarce, and the traditional method has limitations, the single output is relatively low, and the economic efficiency is not high. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a (111) crystal plane large single crystal diamond with strong impurity removal ability, which makes the diamond preferentially accumulate along the (1,1,1) crystal plane, has a large synthetic particle size and high yield, and a preparation method thereof.

[0004] The object of the present invention is achieved by the following technical solution: A method for preparing a large single crystal diamond with a (111) crystal plane comprises the following steps:

[0005] S1. Alloy powder raw materials are configured according to the mass ratio and alloy powder is prepared by water mist method;

[0006] S2. Melting the alloy powder into rods and cutting them into catalyst sheets;

[0007] S3 will be used to carve out a magnesium oxide sheet to accommodate the seed hole as a crystal bed;

[0008] S4. Assemble according to a specific structure;

[0009] S5. Perform high temperature and high pressure synthesis in a six-sided top press according to the temperature and pressure curve.

[0010] Preferably, in step S1, the alloy powder raw material is composed of 60%-61.5% iron metal, 0.1%-0.5% copper metal, 2.5%-2.8% cobalt metal, 30.0%-30.5% nickel metal, and 5%-6.3% silicon, calcium and barium in a mass ratio.

[0011] Preferably, in step S2, the catalyst sheet has a thickness of 10 mm.

[0012] Preferably, in step S3, the magnesium oxide sheet is prepared according to the following steps: light high-purity magnesium oxide powder with d50 is added with 5% water glass solution and mixed evenly, allowed to stand for 24 hours, pressed into 1.5 mm original sheets, and dried at 800°C.

[0013] Preferably, in step S3, the seed hole has a diameter of 0.5 mm and a depth of 0.5 mm.

[0014] Preferably, in step S4, the specific structure is to place the crystal bed on a 1 mm thick nickel sheet, put on a magnesium oxide tube, put in a catalyst sheet and a carbon source in turn, use a magnesium oxide sheet as isolation at the upper end, and the outer layers are respectively a heating tube, a conductive sheet, and an insulation tube, and the outermost layer is a dolomite ring, a talc ring, a plug, and a talc block.

[0015] The present invention also provides a large single-crystal diamond with (111) crystal plane synthesized according to the above method.

[0016] The present invention has the following advantages: a method for preparing a large single crystal diamond with a (111) crystal face is used, and the industrial large single crystal diamond prepared by the method of the present application has a particle size of 10 mm, a high yield, a (1,1,1) crystal face accounting for the largest proportion, and other faces are almost absent, and at the same time, the transparency is good, the color is golden, and there are no impurities inside, and the diamond can be used for cutting (111) face diamond single crystal wafers, so it has good application prospects and considerable economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the assembly structure of the present invention;

[0018] Figure 2 is a schematic diagram of high temperature and high pressure synthesis of the present invention;

[0019] Figure 3 It is a product schematic diagram of the present invention.

[0020] In the figure, 1. talc block; 2. plug; 3. talc ring; 4. dolomite ring; 5. insulation tube; 6. heating tube; 7. conductive sheet; 8. magnesium oxide sheet; 9. magnesium oxide tube; 10. carbon source; 11. catalyst sheet; 12. crystal bed; 13. nickel sheet. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the specific embodiments of the present invention will be clearly and completely described below.

[0022] Example 1: A large single crystal diamond with a (111) crystal plane is prepared according to the following method:

[0023] S1. The catalyst alloy powder is composed of the following raw materials in the following mass ratios: 60.5% iron metal, 0.5% copper metal, 2.5% cobalt metal, 30.5% nickel metal, 6% silicon calcium barium, wherein Si45%-55%, Ca8%-12%, Ba8%-12%, C≤0.4%, S≤0.03%, P≤0.03% in silicon calcium barium;

[0024] S2. The alloy powder of 250 mesh was made by water mist method and melted into metal alloy rods, and a 10 mm thick catalyst sheet was prepared by wire cutting;

[0025] S3. A 5% water glass solution was added to a lightweight high-purity magnesium oxide powder of d50 and mixed evenly, allowed to stand for 24 hours, pressed into a 1.5 mm original sheet, dried at 800 ° C, and a hole with a diameter of 0.5 mm and a depth of 0.5 mm was made on the magnesium oxide sheet using an engraving machine, and a diamond single crystal was placed as a seed crystal for standby;

[0026] S4. Figure 1 As shown, the crystal bed 12 is assembled according to a specific structure, and a 1 mm thick nickel sheet 13 is placed, and a magnesium oxide tube 9 is put on, and a catalyst sheet 11 and a carbon source 10 are placed in sequence. The upper end is isolated with a magnesium oxide sheet 8, and the outer layers are respectively a heating tube 6, a conductive sheet 7, and an insulation tube 5. The outermost layer is a dolomite ring 4, a pyrophyllite ring 3, a plug 2, and a pyrophyllite block 1, wherein the specific dimensions are a pyrophyllite block 42.5*85 mm, a plug Φ54*2.8*Φ 17*20mm, pyrophyllite ring Φ65*Φ17*11.5*Φ54*2.8mm, dolomite ring Φ65*Φ17*8.5mm, insulation tube Φ65*Φ54*45mm, heating tube Φ54*Φ50*45mm, conductive sheet 8mm, magnesium oxide sheet 4.5mm, magnesium oxide tube Φ50*Φ46*29mm, carbon source 12mm, catalyst sheet 10mm, crystal bed 1.5mm, nickel sheet 1mm;

[0027] S5. High temperature and high pressure synthesis: by monitoring the temperature inside the synthesis chamber of the six-sided top press, and combining the unique pressure and temperature ratio synthesis process, such as Figure 2 As shown, the diamond crystal is preferentially grown along the (1,1,1) crystal plane, and the growth time is 72 hours. The final macroscopic crystal form is a high-quality single crystal diamond with a particle size of 10 mm and a large proportion of regular octahedrons, as shown in FIG. Figure 3 shown.

[0028] Example 2, a (111) crystal plane large single crystal diamond, its synthesis method is basically the same as that of Example 1, the difference lies in the raw material composition of the catalyst alloy powder by mass ratio: 61.5% iron metal, 0.5% copper metal, 2.5% cobalt metal, 30.5% nickel metal, and 5% silicon calcium barium.

[0029] Example 3, a (111) crystal plane large single crystal diamond, its synthesis method is basically the same as that of Example 1, the difference lies in the raw material composition of the catalyst alloy powder by mass ratio: 60% iron metal, 0.4% copper metal, 2.8% cobalt metal, 30.5% nickel metal, and 6.3% silicon calcium barium.

[0030] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a large single crystal diamond with a (111) crystal plane, characterized in that: The following steps are included: S1. Alloy powder raw materials are configured according to the mass ratio and alloy powder is prepared by water mist method; S2. Melting the alloy powder into rods and cutting them into catalyst sheets; S3 will be used to carve out a magnesium oxide sheet to accommodate the seed hole as a crystal bed; S4. Assemble according to a specific structure; S5. Perform high temperature and high pressure synthesis in a six-sided top press according to the temperature and pressure curve.

2. The method for preparing a large single crystal diamond with a (111) crystal plane according to claim 1, characterized in that: In step S1, the alloy powder raw material is prepared in a mass ratio of 60%-61.5% iron metal, 0.1%-0.5% copper metal, 2.5%-2.8% cobalt metal, 30.0%-30.5% nickel metal, and 5%-6.3% silicon, calcium and barium.

3. The method for preparing a large single crystal diamond with a (111) crystal plane according to claim 1, characterized in that: In step S2, the thickness of the catalyst sheet is 10 mm.

4. The method for preparing a large single crystal diamond with a (111) crystal plane according to claim 1, characterized in that: In step S3, the magnesium oxide sheet is prepared according to the following steps: light high-purity magnesium oxide powder with d50 is added with 5% water glass solution and mixed evenly, left to stand for 24 hours, pressed into 1.5 mm original sheet, and dried at 800°C.

5. The method for preparing a large single crystal diamond with a (111) crystal plane according to claim 1, characterized in that: In step S3, the seed hole has a diameter of 0.5 mm and a depth of 0.5 mm.

6. The method for preparing a large single crystal diamond with a (111) crystal plane according to claim 1, characterized in that: In step S4, the specific structure is to place the crystal bed on a 1 mm thick nickel sheet, put on a magnesium oxide tube, put in the catalyst sheet and carbon source in turn, use a magnesium oxide sheet as isolation at the top, and the outer layers are heating tubes, conductive sheets, and insulation tubes respectively. The outermost layer is a dolomite ring, a talc ring, a plug, and a talc block.

7. A large single crystal diamond with (111) crystal plane prepared by the method according to any one of claims 1 to 6.

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