JPS59501013A - Method for producing diamond particles with selected morphology - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The field of the invention is generally the production of materials useful in grinding and polishing, and more particularly The present invention relates to the field of methods for producing diamond particles for applications in the field of diamond particles.

Background technology Synthetic diamond particles are manufactured by several methods known in the art. For example, Industrial diamond particles are manufactured at 130 kbar and 3000'C. It's here. Another method uses nickel or iron as a catalyst and uses 27 kg The particles are produced at Bar and 14000C. These high temperature methods Since General Electric uses such a method, Don't call it the electric type Yuyamond. Industrial Edge Diamond Particles The manufacturing method for Noiya is from about 1ooo to 200,000, and from 0.5 to 1. Shock wave synthesis of diamond particles under conditions achieving a pressure of 5 megabar include. This is generally E,1. This is the method used by DuPont and its Therefore, such particles are called DuPont diamonds.

Yet another method of producing engineered edge diamond particles was introduced on October 1, 1980. Disclosed in Patent No. 4.228.1'42 by the present inventor issued on the 4th This is how it is done. This patent specification is incorporated herein by reference.

When the product of the method confirmed above is observed using a scanning electron microscope, the particles The seeds are rather stocky in shape, and some exhibit a single-crystalline appearance. I understand. Other particles are polycrystalline. Polycrystalline diamond particles are multilayered. and is therefore generally considered to be the preferred type for sanding and grinding. reactor. Diamond particles in the abrasive range produced by these methods are typical The average size ranges from 0.5 to about 85 microns, and these are called micron powders. Get found out. Particle size of diamond particles in the grinding range, mainly natural type and G, E, type The range is typically 85 to 850 microns in size and is often diamond-grid. Call me Dodo. Various dimensional separation techniques are used to obtain very uniform particle size fractions. Separate the particles using techniques. Precision grade with relatively small dimensions on grad, e) particles are used for finish grinding, lapping and polishing. , while those with relatively large dimensions - often cut for grinding, drawing or drilling. It can be used by incorporating or connecting with machining.

All of the above known methods produce particles with a generally stocky structure or morphology. and therefore act quite uniformly in the various uses of these particles. But long In view of the superior performance of particles with multi-nuclei for grinding applications, such It would be desirable to uniformly obtain structured particles.

The particular shape (morphology) of particles in the pond also has advantages for a variety of applications. child In the shape or form of fibers used as reinforcement material be. Methods for growing experimental filamentous diamond crystals are known. This way Una crystals have very high strength. Such filament crystals are seeds of Kyoga. Grows on diamond single crystal (for example, J-manbu crystal growth (J-manbu crystal growth) of 0rysl;al, Growth) 2.680 pages 1968 reference). Each type of crystal is supported individually, and the filamentous diamond crystals are supported in the carbon-containing gas phase. It grows epitaxially. Therefore, a large scale of such diamond fibers Production is impractical by these methods.

Therefore, we propose a method for producing diamond particles having a predetermined structure or morphology. It is one object of the present invention to provide.

The surface of the particles is extremely irregular, making them difficult to use for grinding and polishing purposes. It is another object of the present invention to provide Mondo particles.

Selected from fibers, stubby particles, porous particles with desired shape or non-porous particles. Is it always an irregular shape? It is a further aspect of the present invention to produce diamond particles having It is one purpose.

Other objects of the invention will become apparent upon consideration of the following description. cormorant.

Disclosure of invention According to the present invention, the intended diamond grains are organic and have an initial structure. Select or assemble it so that it has the shape of a child. This structure is then substantially Let's transform it so that it is beta carbon f-arsenic, which has the structure of Next, the inventor No. 4,228,142 or an equivalent method disclosed in U.S. Pat. Use a low-temperature, low-pressure method to convert this coal mine silicon into diamond.

Best mode for carrying out the invention As discussed in U.S. Pat. No. 4,228,142, diamond The particles are composed of perfluorocarbons and silicon carbide at about 800 to 1200'C4. It can be produced by reaction at any temperature range. Optimize diamond particles The preferred temperature for production is about 1ooo°C. Furthermore, silicon carbide is The reaction is more likely to occur in the beta phase (close-packed cubic system) than in the phase phase (hexagonal system). Seems to go more easily. The presence of iron or nickel as accelerators can also be avoided. It's beneficial. 1.Diamond is stable at 1600°C1 under the conditions. Therefore, it is possible to expand the reaction range while increasing the reaction speed change. Newsletter of H, yB,, dai/l/(J)yer): ■nd, Di, am ond QOnfo, 111967 “Physical and chemical properties of diamonds” reference〕.

Silicon carbide is commercially available from many sources. Silicon carbide is an example For example, it can be used in many high temperature applications. Also, SiC fibers are Used to strengthen minium. One conventional method for producing silicon carbide is This is due to the use of rice husk (rice hqilS). Rice husks are rare L 7 agricultural waste products. Rice grains, along with rice husks, have a high carbon content and high Norica content. (5io2) content. These rice husks are heated at a temperature of about 18,200C. When heated, the rice husks convert into silicon carbide due to the amount of carbon and silicon. do. A method for producing silicon carbide from rice grains is disclosed in US Pat. No. 3,754. [ ] No. 76 and No. 4,248,844. obtained product It has several shapes, including needle-like, stubby, cylindrical, and rough-surfaced cylindrical shapes.

The needles can be separated from the total silicon carbide by flotation, and then they are separated from the gold. You can use it to strengthen your MatriX. needle-like object The remaining form of silicon carbide from manufacturing is considered a waste product but can be used for other uses. Useful.

Crushed silicon carbide is also conventionally produced using other raw material components. The Kei The elemental parts include silicon metal, various silicates, phosphoric acid, silicic acid, and silicones. substances such as diatomaceous earth, radiolaria, etc. Derived from naturally occurring substances. Carbon sources are typically coke, graphite, charcoal, resins, and carbon. These include bomb black and naturally occurring carbon materials. Depending on the reaction conditions, the size and SiC particles of the shape are obtained, which are mainly of the beta type. these Representative examples of other methods include US Pat. No. 4,136,689 and US Pat. No. 162,167. U.S. Patent No. 3,927,1.81 No. 3,726,7 describes the manufacture of hollow spheres of Sj,C. No. 67 describes the production of "corrugated paper" SIC.

The waste products from the milling process for the production of silicon carbon needles or fibers are As a result of our research, we found that fluorocarbons were of silicon carbide for the production of diamond particles via double decomposition using carbon It turned out to be a cheap source. Chi-ray diffraction analysis of the silicon carbide revealed that the baked phase The ratio of silicon carbide to alpha phase silicon carbide was shown to be approximately 2=1. Furthermore, Analysis revealed that the material contained approximately 25% carbon, 25% alpha phase carbon and 7% carbon. It was shown to have 50% beta phase silicon carbide.

261 g of this material was mixed with 5 parts by weight of iron powder. This item is made of stainless steel. In the retort, use a porous graphite device to pass the four through the retort. It was heated while flowing fluorocarbon. The experiment was continued for 18 hours at 100,000 Ta. The weight of the product powder was 173g. By spectroscopic analysis, by weight, 5 % iron, 1% fluorine tile [350 parts silicon per million parts] Shown. The obtained product is subjected to leaching and gravimetric beneficiation to make the product diamond. isolated as a powder. 56 carats from 150g of reacted powder (1 carat is 0 ．． A carbo yield equal to 2 g was determined. Based on the amount of beta silicon carbide in the powder. free carbon, iron and alpha silicon carbide as well as the starting base in the powder. Taking into account the amount of silicon carbide, the yield of this reaction was calculated to be 17.4%. It was done. X-ray diffraction studies of the product reveal diamonds and the forming diamonds. The presence of some graphite, which may be entrained within the particles, was shown. These dies Yamond particles are black, probably due to this graphite.

The unexpected morphology of the diamond particles was noted. Compared to the starting silicon carbide morphology In such cases, the morphology of the diamond appears to be substantially that of the silicon carbide. Ta. In other words, these diamond particles are based on the starting 5iO8 Special Publication No. 59-50101. 3 (4) It had a precise correspondence in matter. In this way, a small amount of If silicon carbide grains are present, some of the diamond particles also have a needle-like shape. It is in a state of Other shapes of silicon carbide particles, such as roughened cylinders, can be It becomes a cylindrical object with a rough surface in the powder. In addition, relatively hollow silicon carbide What appears to be an elementary particle similarly becomes a hollow diamond particle. Therefore As a result of research, the desired morphology of diamond particles was obtained from the starting material, i.e. It is said that it can be produced by selecting the form of silicon carbide in I understand. Individual diamond crystals can have sizes up to 75 microns in diameter. Polycrystalline diamond agglomerates and/or A porous shape was generated.

In addition, the diameter is from 70 to 700 microns, and the length is from OO to 60D microns. rods with a width of 1 micron and a whisker of 30 microns in length and a whisker with a width of 10 microns. Needles with a length of 750 microns were produced. Viewed using a scanning electron microscope These estimated dimensions are given by way of example only and are not intended to limit the method. There isn't.

This research shows that if it is possible to produce silicon carbide in various shapes, Proof that various shapes of diamond shapes are possible and perhaps unlimited. I made it clear. i.e. a mixture of silicon carbide shapes such as those obtained from rice husk If the starting silicon carbide is mostly unique, If the diamond has a specific shape, it is possible to produce diamonds with a high concentration Probably.

Therefore, diamond needles can be made from acicular silicon carbide, and this Various compositions can be used in a manner similar to that in which silicon carbide has traditionally been used. It can be used to strengthen. Furthermore, the extremely high The porous diamond structure makes it more suitable for grinding wheels etc. The layers can be completely combined. Very rough diamond particles may be used in grinding techniques Very small diamond particles can be used for polishing. did Therefore, this allows the formation of various sizes and shapes at relatively low temperatures and normal pressures. This makes it possible to form shaped diamond particles.

Almost all organic materials can be heated to 1 to 50% carbon residue under an inert atmosphere such as argon. can produce distillates. Because the shape of the organic substance is often the same as that 11, The shape of the carbonized particles can be adjusted. Using solid or hollow starting materials can be used. Before or after carbonization, silica gel and ether sol silicic acid, methyltrichlorosilane (MTS) liquid, silicic acid) IJ u or other 7-liquid or silicon-containing substances. , the body could then be reacted with a carbon body to produce silicon carbide. M When using TS liquid, the MTS liquid quickly reacts with moisture in the air and creates silica. Forms a film or shell containing elements.

Some naturally occurring pollen has a very rough appearance. Typical of these is the pollen of plants such as daisy, sunflower, dandelion, and calendula. a large number of these Ann Arbor Science (Ann Arbor, Ann Arbor, Minnesota) Published by Arbor 5Cjence), “Z Particle Atlas ( The Particle At1as) 2nd edition (1980) . When converted to silicon carbide by the Goni process cited above, the resulting carbonized Converting silicon into diamond particles that also have a rough outline Be able to do it.

In addition, carbonization to convert to SiO, and then a compound having a similar morphology to the starting material. Naturally occurring diamond particles with other shapes that can be converted into corresponding diamond particles. There are organic carbonaceous particles. Typical of such particles are Pollen from willow, privet, etc., which has an uneven surface that acts as a binder. .

Others, such as corn ear hair and milkweed fibers, are extremely elongated; That is, it is made into a needle shape. Things that can be used in the same way are Onamomi and Ama. Is it an object of larger size, such as suzukaketsuki nuts, chestnut nuts, etc.? Ru.

Similarly, naturally occurring substances containing silicon or silica (5i02) as a main component be. These are mixed with carbon in the form of seeds and then at least partially converted into SiC. Be able to transform. Typical such substances are kegs in several forms. Infusorial soil, Radiolarian soil (siliceous skeleton) and Infusorial soil (1nfusorial earth) rth). Production of silicon carbide from e.g. diatomaceous earth and petroleum coke About, Chemical Abstracts, No. 28948r, 80, No. 120 , 1974.

Even materials that would produce alpha-phase silicon carbide could be used. . Alpha silicon carbide has a pressure of about 3 Mpa (4 to 5 ps) at about 25 DO'C. i) that it can be converted to the beta phase by heating in a nitrogen atmosphere. known (communications of the Am, Oer , sac, c-177, 1981). This beta silicon carbide manufacturing process The process promotes the formation of diamond particles. Because, as mentioned above, beta carbonization This is because silicon reacts more easily to form diamond.

The invention is not limited to the use of silicon carbide made from naturally occurring materials. . A specific shape is created by extrusion, press processing, molding, etc. of the necessary Sl and C components. can be configured. Then, it is converted to produce Si and C with the desired shape. and then convert it into a diamond with the same shape. .

In some cases, the entire carbonized casing is There are times when it is not necessary to convert it into ion. Methyltrichlorosilane (MTS) It decomposes into beta silicon carbide at temperatures above H1000'C, so it is not suitable for chemical vapor deposition. As a result, almost all shaped particles (mandrels) in the fluidized bed have at least beta charcoal. It is possible to produce a coating of silicon oxide. Then e.g. carbon tetrafluoride A diamond of that shape can be produced using a reaction. this method The size is much better than that which can be achieved using a complete silicon carbide metathesis reaction method. This makes it possible to produce diamond particles with larger dimensions.

” Using the method described above, diamonds ranging in size from 2 to 100 microns to 1 be able to produce powder particles. The starting material, i.e. silicon carbide, has a wide range of grains. product has a similar wide range of particle sizes and shapes. Contains diamond particles. Diamond grains of specific size and/or shape If the diamond is favorable, a process of sizing and shape selection is added after the diamond is formed. These specific sizes and/or shapes can be separated and extracted. a Alternatively, sizing and shape selection can be performed on the initial silicon carbide. Wear. In this method, only objects of desired size and shape are present and transferred. This makes the process even more efficient in terms of reacting gas stores. 'b shift In this case, leaching is performed to retain only the diamond V part of the reaction product. and density separation steps may be required.

In the above-cited patent specification AJ228.142, fluorine is used as a reactive gas. Although fluorocarbons, more specifically tetrafluorocarbons, are used, Other gases may also be useful in carrying out the process. For example, the fluorine atom diamond of silicon carbide by replacing at least a portion with other atoms In some cases, it may be possible to convert to In this way, several types can be used in the present invention. /・rocarbons may be suitable. These halocarbons are carbon and fluorine , chlorine, bromine, iodine and/or hydrogen. like this Several combinations of gases offer greater capacity than carbon tetrafluoride at lower cost. be able to obtain it easily. The decomposition of the carbon used in this method is As long as it does not produce a carbon phase that reacts with silicon carbide to produce a diamond morphology. at the temperature 1 used to convert silicon carbide to diamond. It should not be disassembled. When effective gaseous carbon is produced at the reaction temperature For example, solid carbons in the form of seeds such as Tefrine are also used. Be able to do it.

From the above, one skilled in the art can produce diamond particles with a wide range of sizes and shapes. (You will understand that it is possible to is governed by the shape of the silicon carbide body subjected to the metathesis conversion to . Therefore Diamond particles with a specific shape are intentionally shaped to be silicon carbide particles with a specific shape. Be generated by becoming. Diamond l-″′ contains approximately 1 silicon carbide particle. It is produced by subjecting it to a halocarbon atmosphere at 000°C. desired A suitable diluent gas (helium, argon, nitrogen, hydrogen, etc.) and An inert filler material such as excess carbon in the form of carbon can be used. Therefore The diamond particles produced vary in their size and shape as well as in these shapes. Useful due to its shaped exterior. Those diamond particles are shaped, strengthened and ground , be able to achieve particularly desirable results in technical fields such as polishing.

The above conditions employed in demonstrating the invention are not necessarily the most efficient. This will also be recognized by those skilled in the art. Lines are subject to falls and other confusion. In the rotary furnace, where the coalescence occurs, the conversion between halocarbon and silicon carbide is increased. causing contact. This results in reduced reaction times and higher yields. Let it go. A small flow reactor could also be used.

Furthermore, since the reaction is exothermic, there may be a violent reaction in the material to be treated and/or in the furnace. There are times when it is undesirable to be cautious and cautious when the temperature rises rapidly. In addition, through a series of environments transfer the material, converting silicon carbide and forming the final diamond in a continuous process. It will be recognized that one should be able to carry out generation. Do it like this processing equipment for automatic production of diamond products of selected size and shape. It is also possible to supply the ingredients to the location.

Although the preferred embodiments of the invention have been illustrated and described, various modifications thereof will occur to those skilled in the art. Of course, what becomes clear to the person must be understood. Therefore, the scope of the present invention is You are to be limited only by the scope of the appended claims and their particular subject matter.

Claims (1)

[Claims] 1 Silicon carbide particles with selected size and shape are coated with halocarbon. Metathesis reaction treatment at temperatures from about 800°G to below about 1600°C in the presence of Industrial Diameter 2 with selected size and shape features that make it easy to manage Method of manufacturing particles. 2 The silicon carbide particles are mainly beta silicon carbide, and the halocarbon particles are 2. The method according to claim 1, wherein the -zan gas is carbon tetrafluoride. 6. The silicon carbide is a mixture of alpha silicon carbide and beta silicon carbide. and prior to the metathesis reaction, the alpha silicon carbide is added to a concentration of about 1 to about M. Temperatures from about 1800°C to about 2501]’Ct under nitrogen atmosphere up to Pa By heating the alpha silicon carbide to a larger amount of beta silicon carbide. A method according to claim 1, characterized in that the method is converted into 4. Under conditions that produce carbonized particles having the selected size and shape, heating a substance and then adding at least a portion of said carbonized particles in the presence of a silicon-containing substance; to form the silicon carbide particles. The method according to claim 1. 5. The silicon-containing particles having the selected size and shape are added to a carbon-containing material. heating under conditions sufficient to form the silicon carbide particles in the presence of The method according to claim 1, wherein the silicon carbide particles are produced by: 6. By depositing silicon carbide on the mandrel, 7. Prior to the double decomposition reaction. 7. A method as claimed in claim 6, characterized in that said mandrel is removed by 8. The mandrel is carbon, and the mandrel is made of carbon by oxidizing the carbon. 8. The method of claim 7 for removing. 9. Mix the carbonaceous material and the silicon-containing material to form the selected size and shape. and then applying conditions sufficient to form the silicon carbide particles. Under the conditions, the pre-carbonaceous material in the particles is allowed to react with the silicon-containing material. 2. The method according to claim 1, wherein the silicon carbide particles are produced from the silicon carbide particles. 10. The method according to claim 4, wherein the organic substance is rice husk. 11. The method according to claim 10, wherein the carbonization step and the conversion step are performed at the same time. Law. 12. Prior to the conversion step, the carbonized particles are treated with the silicon-containing substance. 5. The method of claim 4, wherein the silicon carbide particles are produced by: 1) The halocarbon has a phase 18 at the double decomposition reaction temperature. 2. A method according to claim 1, wherein the method decomposes only at the relevant temperature. 14 The silicon carbide particles have a range of sizes and shapes, and the silicon carbide particles have a range of sizes and shapes, and said selected size from said range prior to said metathesis reaction to produce 2. The method according to claim 1, wherein the size and shape are separated and taken out. 15 The silicon carbide particles have a range of sizes and shapes, and said selected of said diamond particles from all products of said metathesis reaction of elementary particles. The method according to claim 1, wherein the method is separated in size and shape and taken out. 16. Claim 2, wherein the metathesis reaction is carried out at a temperature of about 1 ooo'c. How to put it on. 17. The diamond particles are elongated and have a diameter of about 1 to about 10 microns. a diameter of from about 30 to about 750 microns and a length from about 30 to about 750 microns. The method described in Section 1. 18. The diamond particles have a selected size from about 1 to about 600 microns. 2. A method according to claim 1, having a very rough surface. 19. The selected diamond particles are substantially between about 70 and 200 microns. a rod-shaped object having a diameter of up to and a length of about OO to 600 microns; Moreover, in this case, the rod-shaped object is highly porous. 13. The method described in item 1 of scope (2). 20 Claims 1, 4, or 9 in which the steps are performed substantially continuously Method described. 21. The method according to claim 1, wherein the double decomposition reaction is carried out in a rotary furnace. 22 The diamond particles are approximately 160. To keep the temperature below OoC, 22. The method of claim 21 further comprising operating said furnace. 2 diameters from about 70 to 200 microns and from about 300 to 600 microns using a silicon carbide rod having a length substantially of diameter of about 70 to 200 microns 1 and about 30 to 6 Diamond rods with lengths up to 0.00 microns. 24. Produced by the method according to claim 1, wherein the silicon carbide particles are porous. porous diamond particles. 25. Diamond produced by the method according to claim 10 or 11. particle. 26 Produced by the method according to claim 1, wherein the silicon carbide is a fiber. diamond fiber.