CN114888926A - Novel sealing material pressing device and process for synthetic diamond - Google Patents
Novel sealing material pressing device and process for synthetic diamond Download PDFInfo
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- CN114888926A CN114888926A CN202210333967.6A CN202210333967A CN114888926A CN 114888926 A CN114888926 A CN 114888926A CN 202210333967 A CN202210333967 A CN 202210333967A CN 114888926 A CN114888926 A CN 114888926A
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- 238000003825 pressing Methods 0.000 title claims abstract description 78
- 229910003460 diamond Inorganic materials 0.000 title claims abstract description 62
- 239000010432 diamond Substances 0.000 title claims abstract description 62
- 239000003566 sealing material Substances 0.000 title claims abstract description 31
- 238000000034 method Methods 0.000 title claims abstract description 30
- 238000007789 sealing Methods 0.000 claims abstract description 22
- 239000000126 substance Substances 0.000 claims abstract description 15
- 230000002194 synthesizing effect Effects 0.000 claims abstract description 4
- 239000000463 material Substances 0.000 claims description 50
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 48
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 claims description 36
- 239000000377 silicon dioxide Substances 0.000 claims description 24
- 235000012239 silicon dioxide Nutrition 0.000 claims description 24
- 229910052903 pyrophyllite Inorganic materials 0.000 claims description 15
- ZLNQQNXFFQJAID-UHFFFAOYSA-L magnesium carbonate Chemical compound [Mg+2].[O-]C([O-])=O ZLNQQNXFFQJAID-UHFFFAOYSA-L 0.000 claims description 13
- 239000001095 magnesium carbonate Substances 0.000 claims description 13
- 229910000021 magnesium carbonate Inorganic materials 0.000 claims description 13
- 239000000395 magnesium oxide Substances 0.000 claims description 13
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 claims description 13
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 claims description 13
- 239000003795 chemical substances by application Substances 0.000 claims description 12
- 238000003756 stirring Methods 0.000 claims description 12
- 238000012546 transfer Methods 0.000 claims description 11
- 239000010459 dolomite Substances 0.000 claims description 10
- 229910000514 dolomite Inorganic materials 0.000 claims description 10
- 238000010438 heat treatment Methods 0.000 claims description 10
- 239000002994 raw material Substances 0.000 claims description 9
- ODINCKMPIJJUCX-UHFFFAOYSA-N Calcium oxide Chemical compound [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 claims description 6
- 238000000748 compression moulding Methods 0.000 claims description 6
- 238000010304 firing Methods 0.000 claims description 6
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 6
- 238000002156 mixing Methods 0.000 claims description 6
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 claims description 6
- 238000000465 moulding Methods 0.000 claims description 4
- 230000001629 suppression Effects 0.000 claims description 4
- 239000004115 Sodium Silicate Substances 0.000 claims description 3
- 230000006835 compression Effects 0.000 claims description 3
- 238000007906 compression Methods 0.000 claims description 3
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 claims description 3
- 229910052911 sodium silicate Inorganic materials 0.000 claims description 3
- 238000004519 manufacturing process Methods 0.000 abstract description 6
- 230000005540 biological transmission Effects 0.000 abstract description 3
- 239000013078 crystal Substances 0.000 description 15
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 14
- 125000004432 carbon atom Chemical group C* 0.000 description 13
- 229910052799 carbon Inorganic materials 0.000 description 11
- 230000007246 mechanism Effects 0.000 description 7
- 239000010439 graphite Substances 0.000 description 6
- 229910002804 graphite Inorganic materials 0.000 description 6
- 230000006911 nucleation Effects 0.000 description 6
- 238000010899 nucleation Methods 0.000 description 6
- 230000015572 biosynthetic process Effects 0.000 description 5
- 239000003054 catalyst Substances 0.000 description 5
- 239000012071 phase Substances 0.000 description 5
- 238000002844 melting Methods 0.000 description 4
- 230000008018 melting Effects 0.000 description 4
- 150000001721 carbon Chemical group 0.000 description 3
- 238000000605 extraction Methods 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- 239000002904 solvent Substances 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 238000004781 supercooling Methods 0.000 description 2
- 238000003786 synthesis reaction Methods 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000012466 permeate Substances 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 239000007790 solid phase Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
- 230000001131 transforming effect Effects 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B28—WORKING CEMENT, CLAY, OR STONE
- B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
- B28B3/00—Producing shaped articles from the material by using presses; Presses specially adapted therefor
- B28B3/02—Producing shaped articles from the material by using presses; Presses specially adapted therefor wherein a ram exerts pressure on the material in a moulding space; Ram heads of special form
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B28—WORKING CEMENT, CLAY, OR STONE
- B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
- B28B11/00—Apparatus or processes for treating or working the shaped or preshaped articles
- B28B11/24—Apparatus or processes for treating or working the shaped or preshaped articles for curing, setting or hardening
- B28B11/243—Setting, e.g. drying, dehydrating or firing ceramic articles
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
- C04B28/24—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing alkyl, ammonium or metal silicates; containing silica sols
- C04B28/26—Silicates of the alkali metals
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Ceramic Engineering (AREA)
- Mechanical Engineering (AREA)
- Structural Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Inorganic Chemistry (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Crystals, And After-Treatments Of Crystals (AREA)
Abstract
The invention provides a novel device and a process for pressing a sealing material for synthesizing diamond. The novel synthetic diamond sealing material pressing device comprises: the sealing material pressing equipment comprises a novel pressing mold frame; the original pressing mold frame in the sealing material pressing equipment is replaced by the novel mold frame designed by the invention, and then the diamond is produced. The novel sealing material pressing device and the process for synthesizing the diamond, which are provided by the invention, have the advantages that the whole process performance of the pressure transmission and the sealing performance of the pressing die frame can be improved and optimized, so that the synthetic production process of the diamond becomes stable and is easy to control, the production efficiency can be improved, and harmful substances are prevented from entering the pressing die frame to influence the growth of the diamond.
Description
Technical Field
The invention belongs to the technical field of synthetic diamond, and particularly relates to a novel device and a process for pressing a sealing material for the synthetic diamond.
Background
Synthetic diamond, which is an artificial diamond, has been studied since the 18 th century after it was confirmed to be composed of pure carbon, and has been really successfully and rapidly developed only in the 50 th 20 th century by the development of high-pressure research and high-pressure experimental techniques, and has been widely used in various industries and process industries, the artificial diamond is a material in which non-diamond-structured carbon is artificially converted into diamond-structured carbon and single crystal and polycrystalline diamond are formed by nucleation and growth, or fine diamond is sintered into polycrystalline diamond at high pressure and high temperature, and when the synthetic diamond is produced, a pressing device is required to press and mold a sealing material for the synthetic diamond, and the conventional pressing device mostly uses a hydraulic pump to directly press the material, but the required pressure for the synthetic diamond is large, when a hydraulic pump directly presses a material, the material generates larger resilience force, the working pressure of the hydraulic pump is increased, and the hydraulic pump is easily damaged, so that the service life of the device is shortened; installing a bottom plate: a pressing mold frame is arranged in the middle of the upper surface of the die; a pressing mechanism: the lower end of the front side of the pressing mechanism is matched and corresponds to the pressing die frame; the check mechanism: the upper ends of the non-return mechanisms are respectively fixedly connected with the left side and the right side of the lower pressing mechanism; wherein: still include end sealing block, the lower extreme sliding connection of end sealing block is in the square mouth that the plate body middle part was seted up at suppression die frame bottom, and the upper end of end sealing block is coincided with the inside die cavity of suppression die frame and is corresponded, and this sealing material suppression device for synthetic diamond can alleviate the material and to the resilience force of top driver part, reduces driver part's operating pressure, improves the life of device at the material pressing in-process.
However, the above structure has disadvantages that the bottom seal block and the pressing mold frame in the pressing device are made of pyrophyllite, but the single pyrophyllite has a low friction coefficient (the pyrophyllite is 0.25), which causes the sealing performance to be poor, and the pyrophyllite generates phase change at high temperature to destroy the original pressure transmission performance, thereby causing pressure loss and large pressure gradient in the pressing mold frame, so that harmful substances in the pyrophyllite can easily enter the pressing mold frame to affect the growth of diamond.
Therefore, there is a need to provide a new sealing material pressing apparatus and process for synthetic diamond to solve the above problems.
Disclosure of Invention
The invention aims to provide a novel sealing material pressing device and a novel sealing material pressing process for synthetic diamond, which can improve and optimize the whole process performance of pressure transmission and sealing performance of a pressing mold frame, so that the synthetic production process of the diamond becomes stable and is easy to control, the production efficiency can be improved, and harmful substances are prevented from entering the pressing mold frame to influence the growth of the diamond.
In order to solve the technical problems, the novel device and the process for pressing the sealing material for the synthetic diamond, which are provided by the invention, comprise the following steps of:
the sealing material pressing equipment comprises a novel pressing mold frame;
an embodiment of the invention comprises raw materials, equipment and the novel pressing mold frame as claimed in any one of claim 1;
s1, raw materials and equipment:
(1) raw materials: pyrophyllite, dolomite and a forming agent (sodium silicate);
(2) an apparatus: a mixer, a press forming device and a firing device;
s2, step:
(1) proportionally adding pyrophyllite and a forming agent into a mixer for mixing and stirring, wherein the stirring time is 50min, and after the completion, storing for 24h for later use to form a sealing layer;
(2) adding dolomite and a forming agent into a mixer in proportion, mixing and stirring for 50min, and storing for 24h for later use after the stirring is finished so as to form a pressure transfer layer;
(3) bonding the sealing layer and the pressure transfer layer by using a forming agent;
(4) placing the bonded article into a compression molding device, and pressing the bonded article into a novel compression mold frame 5;
(5) and placing the formed novel bottom sealing block and the novel pressing mold frame into firing equipment for heat treatment so as to obtain a finished novel pressing mold frame.
As a further scheme of the invention, the pyrophyllite comprises a coarse material, a medium material and a fine material, wherein the particle size of the coarse material is 120 meshes, the content of the coarse material is 30 +/-1%, the particle size of the medium material is 140 meshes 170 meshes, the content of the medium material is 50 +/-1%, the particle size of the fine material is 170 meshes 200 meshes, and the content of the fine material is 20 +/-1%.
As a further scheme of the invention, the dolomite comprises coarse materials and fine materials, wherein the granularity of the coarse materials is 120 meshes, the content of the coarse materials is 80 +/-1%, the granularity of the fine materials is 150 meshes and 130 +/-1%.
As a further aspect of the present invention, the use requirements of the press molding apparatus include the following:
righting a pressing die on the pressing forming equipment without deviating from the central position of a potential plate of the pressing machine;
adjusting a pressure gauge to indicate pressure, and when pressurizing, properly positioning the pressure to ensure the molding size;
correcting the press mould once every 2000 blocks.
As a further scheme of the invention, the pressure of the compression molding equipment is 60-90 MPa.
As a further scheme of the invention, the temperature of the heat treatment is 50-280 ℃, and the temperature of the heat treatment is 3-6 h.
As a further scheme of the invention, the chemical composition of the sealing layer comprises aluminum oxide (Al) 2 O 3 ) Silicon dioxide (SiO) 2 ) Iron oxide (Fe) 2 O 3 ) And ferrous oxide (FeO), the aluminum oxide (Al) 2 O 3 ) Is 37-41%, and the silicon dioxide (SiO) 2 ) Is 41-51%, and the iron oxide (Fe) 2 O 3 ) Is 0.66-0.75%, and the ferrous oxide (FeO) is 1.24-2.96%.
As a further aspect of the invention, the chemical composition of the pressure transfer layer comprises silicon dioxide (SiO) 2 ) Magnesium oxide (MgO), calcium oxide (CaO) and magnesium carbonate (MgCO) 3 ) Said silicon dioxide (SiO) 2 ) 3.5-4.5%, the ratio of magnesium oxide (MgO) is 20-25%, the ratio of calcium oxide (CaO) is 25-30%, and the ratio of magnesium carbonate (MgCO) is 3 ) The proportion of (A) is 10-15%.
As a further scheme of the invention, the original bottom sealing block and the pressing mold frame in the pressing device are replaced by a new bottom sealing block and a new pressing mold frame.
Compared with the related technology, the novel sealing material pressing device and the process for synthesizing diamond provided by the invention have the following beneficial effects:
1. the novel pressing die frame formed by pressing the pressure transfer layer prepared from dolomite and the sealing layer prepared from pyrophyllite can improve and optimize the overall process performance of the pressure transfer and sealing performance of the pressing die frame, so that the synthetic production process of the diamond becomes stable and is easy to control, the production efficiency can be improved, and harmful substances are prevented from entering the pressing die frame to influence the growth of the diamond.
Drawings
In order to facilitate understanding for those skilled in the art, the present invention will be further described with reference to the accompanying drawings.
FIG. 1 is a schematic view of a press apparatus of the present invention;
fig. 2 is a schematic block diagram of the present invention.
1. A sealing material pressing device; 2. novel die frame.
Detailed Description
Referring to fig. 1 and fig. 2, fig. 1 is a schematic view of a pressing apparatus according to the present invention; fig. 2 is a schematic block diagram of the present invention. The novel device and the process for pressing the sealing material for the synthetic diamond comprise the following steps:
the sealing material pressing equipment 1 comprises a novel pressing mold frame 5;
replacing an original pressing mold frame in the sealing material pressing equipment 1 with a novel mold frame 2 designed in the invention, and then producing the diamond;
in addition, the invention also provides a novel pressing process of the sealing material for the synthetic diamond.
An embodiment of the invention comprises raw materials, equipment and a novel press mold frame 5 according to any one of the claims 1;
s1, raw materials and equipment:
(1) raw materials: pyrophyllite, dolomite and a forming agent (sodium silicate);
(2) an apparatus: a mixer, a press forming device and a firing device;
s2, step:
(1) proportionally adding the pyrophyllite and the forming agent into a mixer for mixing and stirring for 50min, and after the stirring is finished, storing for 24h for later use to form a sealing layer;
(2) putting dolomite and a forming agent into a mixer in proportion, mixing and stirring for 50min, and storing for 24h for later use after the stirring is finished so as to form a pressure transfer layer;
(3) bonding the sealing layer and the pressure transfer layer by using a forming agent;
(4) placing the bonded article into a compression molding device, and pressing the bonded article into a novel compression mold frame 5;
(5) and placing the formed novel bottom sealing block and the novel pressing mold frame into firing equipment for heat treatment so as to obtain a finished novel pressing mold frame 5.
The pyrophyllite comprises a coarse material, a medium material and a fine material, wherein the granularity of the coarse material is 120 meshes, the content of the coarse material is 30 +/-1%, the granularity of the medium material is 140 meshes and 170 meshes, the content of the medium material is 50 +/-1%, the granularity of the fine material is 170 meshes and 200 meshes, and the content of the fine material is 20 +/-1%.
The dolomite comprises coarse materials and fine materials, wherein the granularity of the coarse materials is 120 meshes, the content of the coarse materials is 80 +/-1%, the granularity of the fine materials is 150 meshes, and the content of the fine materials is 20 +/-1%.
The use requirements of the press forming equipment comprise the following steps:
righting a pressing die on the pressing forming equipment without deviating from the central position of a potential plate of the pressing machine;
adjusting a pressure gauge to indicate pressure, and when pressurizing, properly positioning the pressure to ensure the molding size;
correcting the press mould once every 2000 blocks.
The pressure of the compression molding equipment is 60-90 MPa.
The temperature of the heat treatment is 50-280 ℃, and the temperature of the heat treatment is 3-6 h.
The chemical composition of the sealing layer comprises aluminum oxide (Al) 2 O 3 ) Silicon dioxide (SiO) 2 ) Iron oxide (Fe) 2 O 3 ) And ferrous oxide (FeO), the aluminum oxide (Al) 2 O 3 ) Is 37-41%, and the silicon dioxide (SiO) 2 ) Is 41-51%, and the iron oxide (Fe) 2 O 3 ) Is 0.66 to 0.75 percent, and the percentage of the ferrous oxide (FeO) is 1.24 to 2.96 percent.
The chemical composition of the pressure transfer layer comprises silicon dioxide (SiO) 2 ) Magnesium oxide (MgO), calcium oxide (CaO) and magnesium carbonate (MgCO) 3 ) Said silicon dioxide (SiO) 2 ) Is 3.5-4.5%, and the ratio of magnesium oxide (MgO) is 20-25%, respectivelyThe content of calcium oxide (CaO) is 25-30%, and the content of magnesium carbonate (MgCO) is 25-30% 3 ) The proportion of (A) is 10-15%.
The synthetic mechanism of artificial diamond is summarized mainly by several kinds of 'solid phase transformation theory', 'catalyst theory' and 'supersaturation-solvent theory', and the commonly accepted view is 'supersaturation-solvent theory', i.e. graphite is firstly dissolved in molten catalyst, then C atoms are separated out, in the course of diamond nucleation and growth, graphite and catalyst are mutually used as solvent and mutually used as solute, graphite firstly makes molten catalyst permeate into it, then C atoms on graphite carbon source are continuously diffused into the melting medium, after the synthetic temperature and pressure reach a certain value, C atoms are separated out from the melting medium under the condition of supercooling, because the atomic structure of the catalyst is close to that of diamond, in particular, it has the ability of attracting electrons, so that the separated C atoms form bonds in face-centered cubic structure, in the course of diamond growth, the melting medium and supersaturation-state C atoms are uniformly distributed around the diamond crystal nucleus, and C atoms are separated out from the melting medium to form a new phase: a diamond crystal nucleus, wherein the process has a thermodynamic process and a kinetic process;
the formation of any new phase comprises two stages with completely different properties, one is the formation of crystal nucleus and one is the growth of crystal nucleus, any property of the system in a specified state must have one and only one fixed value, and the process of the system reaching the state is not related, in the process of transforming graphite into diamond, the exception is not excluded, the state of the crystal nucleus just formed and the state of the crystal nucleus which can stably exist and grow after the formation are considered, when the temperature is T, the carbon atom with the pressure P forms a diamond crystal nucleus and can stably exist and grow, the radius of the crystal nucleus is r, the density of the crystal nucleus is mole per unit volume, and the single crystal nucleus is as follows:
The change in the enthalpy of emergence of the nuclear body is then:
wherein, in the formula: mu.s 1 Chemical potential of diamond nucleus;
μ 0 the chemical potential of carbon atoms when reaching a supersaturation state, namely the chemical potential of an equilibrium state, is the initial state of diamond nucleation;
Δ μ is the difference between the chemical potentials of diamond crystal nucleus and carbon atom;
Δ H herein Model (III) Is that the surface effect is not taken into account,the change in enthalpy of self-extraction when a molar carbon atom crystallizes, in fact, also increases the enthalpy of surface self-extraction when a nucleus of radius r is formed:
ΔH long and long =4πr 2 σ
Wherein, in the formula: σ is the surface tension of the diamond article, so the change in total enthalpy of self-extraction when a fret is formed is:
wherein,
Δ μ =μ 1 -μ 0 =-RTIn(P 1 /P 0 )
in the formula: r is Boltzmann constant;
t is the absolute temperature;
P 1 the pressure required by the stable existence of the diamond crystal nucleus in the carbon phase at the temperature T;
P 0 the pressure at which the system reaches chemical equilibrium;
from raoult's law it can be deduced that: a ═ P 1 /P 0 And a is the degree of supersaturation of the carbon phase at a pressure P and a temperature T, P 1 /P 0 Substitution of Δ μ =μ 1 -μ 0 =-RTIn(P 1 /P 0 ) The formula is as follows:
Δ μ =RTIna
Δ H has a maximum value:
1. when a.ltoreq.1, i.e. the carbon atoms are unsaturated, Δ μ Δ H is greater than or equal to 0, then Δ H is greater than or equal to 0, thus, Δ H>0 and rises with the rise of r, which indicates that the concentration of carbon atoms in the system is not saturated, and diamond grains of any size are difficult to stably exist;
2. when the carbon atoms in the system reach a supersaturated state, namely a is more than or equal to 1, and delta mu is less than or equal to 0, then delta H max Less than or equal to 0, and in the course of increasing supersaturation, the change of delta H along with r is passed through a maximum valueAnd (3) deducing:
when the supersaturation degree reaches a certain value (and a certain supercooling degree exists), the supersaturated carbon atoms enter the radius r>r c When the crystal nuclei are enlarged, the volume term in the formula is dominant, so that the self-enthalpy of the system, namely deltaH, is reduced, and therefore, the seed core can stably exist and can continuously grow into diamond;
② when the degree of supersaturation does not reach a certain value, the supersaturated carbon atoms enter r<rc, which is slightly longer,the table entries in the formula are dominant, so that the self-enthalpy of the system is increased, and the crystal nucleus is automatically reduced immediately to disappear;
thus, r c The "critical radius" referred to as nucleation;
from the above discussion, it is known that the "critical radius" is related to a, which is inversely proportional to the temperature T and directly proportional to the pressure P, which is why the diamond is too much and fine during the diamond synthesis, and from the analysis of the nucleation mechanism of diamond, it is reasonable to use two times of pressure increase in the synthesis process in recent years, that is, at a certain pressure point in the graphite stable region, heating at constant pressure for about 20s, so that the supersaturation degree of carbon in the system is reduced, the nucleation number is reduced, carbon atoms are fully diffused, and the carbon source is increased, so as to meet the requirement of diamond growth, and thus, the diamond can be coarse and defect-free, and the purpose of producing high-quality and coarse-grained diamond is achieved.
Claims (9)
1. A novel synthetic diamond is with sealing material suppression device which characterized in that includes:
the sealing material pressing equipment comprises a novel pressing mold frame.
2. A novel pressing process of a sealing material for synthesizing diamond is characterized in that: comprises raw materials, equipment and the novel pressing mold frame as claimed in any one of claim 1;
s1, raw materials and equipment:
(1) raw materials: pyrophyllite, dolomite and a forming agent (sodium silicate);
(2) an apparatus: the device comprises a mixer, a press forming device and a firing device;
s2, step:
(1) proportionally adding pyrophyllite and a forming agent into a mixer for mixing and stirring, wherein the stirring time is 50min, and after the completion, storing for 24h for later use so as to form a sealing layer;
(2) putting dolomite and a forming agent into a mixer in proportion, mixing and stirring for 50min, and storing for 24h for later use after the completion of stirring so as to form a pressure transfer layer;
(3) bonding the sealing layer and the pressure transfer layer by using a forming agent;
(4) placing the bonded article into a compression molding device, and pressing to form a novel compression mold frame;
(5) and placing the formed novel bottom sealing block and the novel pressing mold frame into firing equipment for heat treatment so as to obtain a finished novel pressing mold frame.
3. The novel sealing material pressing process for synthetic diamond according to claim 1, wherein: the pyrophyllite comprises a coarse material, a medium material and a fine material, wherein the granularity of the coarse material is 120 meshes, the content of the coarse material is 30 +/-1%, the granularity of the medium material is 170 meshes, the granularity of the medium material is 50 +/-1%, the granularity of the fine material is 200 meshes, and the content of the fine material is 20 +/-1%.
4. The novel sealing material pressing process for synthetic diamond according to claim 1, wherein: the dolomite comprises coarse materials and fine materials, wherein the granularity of the coarse materials is 120 meshes, the content of the coarse materials is 80 +/-1%, the granularity of the fine materials is 150 meshes, and the content of the fine materials is 20 +/-1%.
5. The novel sealing material pressing process for synthetic diamond according to claim 1, wherein: the use requirements of the press forming equipment comprise the following steps:
righting a pressing die on the pressing forming equipment without deviating from the central position of a potential plate of the pressing machine;
adjusting a pressure gauge to indicate pressure, and when pressurizing, properly positioning the pressure to ensure the molding size;
correcting the press mould once every 2000 blocks.
6. The novel sealing material pressing process for synthetic diamond according to claim 1, wherein: the pressure of the compression molding equipment is 60-90 MPa.
7. The novel sealing material pressing apparatus and process for synthetic diamond according to claim 1, wherein: the temperature of the heat treatment is 50-280 ℃, and the temperature of the heat treatment is 3-6 h.
8. The novel sealing material pressing process for synthetic diamond according to claim 1, wherein: the chemical composition of the sealing layer comprises aluminum oxide (Al) 2 O 3 ) Silicon dioxide (SiO) 2 ) Iron oxide (Fe) 2 O 3 ) And ferrous oxide (FeO), the aluminum oxide (Al) 2 O 3 ) Is 37-41%, and the silicon dioxide (SiO) 2 ) Is 41-51%, and the iron oxide (Fe) 2 O 3 ) Is 0.66 to 0.75 percent, and the percentage of the ferrous oxide (FeO) is 1.24 to 2.96 percent.
9. The novel sealing material pressing process for synthetic diamond according to claim 1, wherein: the chemical composition of the pressure transfer layer comprises silicon dioxide (SiO) 2 ) Magnesium oxide (MgO), calcium oxide (CaO) and magnesium carbonate (MgCO) 3 ) Said silicon dioxide (SiO) 2 ) 3.5-4.5%, the ratio of magnesium oxide (MgO) is 20-25%, the ratio of calcium oxide (CaO) is 25-30%, and magnesium carbonate (magnesium carbonate) (magnesium oxide) (MgCO 3 ) The proportion of (A) is 10-15%.
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Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
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