Method for manufacturing carbonized or graphitized 3D objects

Abstract

The present invention relates to a method for producing carbonized or graphitized 3D objects, which is based on the task of realizing such objects in a particularly simple manner, by means of which even relatively complex 3D objects can be produced without structural disturbance, which is achieved by mixing a carbonizable or graphitizable material with a flowable organic adhesive or a flowable organic thermoplastic substance to produce a kneadable, substantially form-stable compound and molding this compound to a 3D blank, followed by a drying and outgassing process at elevated temperature for a defined time, followed by carbonization or graphitization of the 3D blank in a furnace under a protective gas atmosphere to produce the 3D object, wherein the temperature required for carbonization or graphitization is approached at a low heating rate.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a carbonized or graphitized 3D object.

Background Art

[0002] Such carbonized or graphitized 3D objects, which are also suitable for use at high temperatures, can be various members, for example, the lining of a furnace, building members, or any hollow body, container or crucible.

[0003] Since 3D objects cannot generally be manufactured by simply molding carbon black or graphite and then sintering, it is generally necessary to manufacture a suitable carbon-containing and moldable compound. For this purpose, it is usually to mix carbon black, coke or graphite in the form of granules with a suitable binder, for example a thermoplastic binder. Considered as binders are pitches based on coal tar or petroleum pitch, or synthetic resins.

[0004] Next, these mixtures are pressed and molded into green compacts, and then carbonized or graphitized in a furnace at about 3,000 °C, during which the binder decomposes into volatile components. As residues of the binder, carbon and binder coke remain in the form of a porous structure.

[0005] Instead, the green compacts can also be placed between each electrode in the furnace as resistance elements and heated by an electric current.

[0006] The difficulty during the carbonization or graphitization of such compacts is that volatile substances violently release gas to a certain extent at the high temperatures required in that case, which can cause structural disturbances such as cracks and gas inclusion.

Summary of the Invention

Problems to be Solved by the Invention

[0007] The present invention is based on the problem of providing a method for manufacturing carbonized or graphitized 3D objects that is particularly difficult to realize and enables the production of relatively complex 3D objects without structural disturbance. [Means for solving the problem]

[0008] The aforementioned problem is to produce a kneadable and nearly dimensionally stable compound composed of a carbonizable or graphitizable material and a fluid organic adhesive or a fluid thermoplastic organic substance, and to mold this compound by hand using a suitable template to create a 3D blank, or to use Teflon (trademark) Alternatively, a 3D blank is created by molding it in a silicone mold and removing the 3D blank from this mold. The 3D blank is then dried and gas-released at room temperature or up to 100°C to be converted into a 3D molded product. The 3D molded product is then stabilized and homogenized in air at temperatures ranging from 140°C to a maximum of 450°C. Finally, the 3D molded product is carbonized or graphitized in a furnace under a protective gas atmosphere to produce a 3D object, the temperature required for carbonization or graphitization being achieved by approaching it at a low heating rate.

[0009] Materials that can be carbonized or graphitized are preferably carbon black, graphite powder, natural graphite, cellulose or corn starch, or mixtures of some or all of these materials.

[0010] To influence the strength or porosity of the manufactured 3D object, bamboo fibers, cotton fibers, hemp fibers, sisal fibers, or graphite fibers can be mixed into a material that can be carbonized or graphitized while maintaining its kneadability. 。

[0011] Protection Argon or helium is preferably used as the protective gas.

[0012] Alternatively, the 3D blank can be subjected to a stabilization and homogenization process after the drying process at a stabilization temperature of 170°C in air or up to 450°C in air to produce a 3D molded product, with 250°C being preferred.

[0013] The stabilization and homogenization processes can, in principle, be carried out under a protective gas such as argon.

[0014] Stabilization and homogenization of 3D blanks can also occur during furnace heating.

[0015] In this invention, the 3D molded product is further carbonized at a constant temperature of approximately 1,000°C until pure carbon with various crystalline structures is produced, thereby creating a 3D object.

[0016] In another continuation of the present invention, the 3D molded product is graphitized at a constant temperature of 2,000°C or higher.

[0017] Finally, 3D molded parts can be completely graphitized at temperatures exceeding 2,500°C.

[0018] Preferably, graphitization is carried out at a heating rate of about 1°C / min until the desired temperature is reached, and then heat treatment is performed for about 30 minutes, depending on the size of the 3D molded product.

[0019] In one preferred embodiment of the present invention, a kneadable compound may be mixed with metal powder or silicon powder so that metal carbide or silicon carbide is formed during high-temperature processing of a 3D molded product at >1,000°C under a protective gas.

[0020] Graphitized foamed 3D objects can also be converted into 3D objects made of SiC in a furnace at a temperature of >1,200°C and a pressure of approximately 30 mbar, using argon as a carrier gas to supply gaseous SiO.

[0021] The present invention will be described in more detail below based on examples. [Examples]

[0022] In a first process step, a kneadable and substantially shape-stable compound is produced by mixing a carbonizable or graphitizable material with a fluid organic binder or a fluid thermoplastic organic substance, and then this compound is shaped to form a 3D blank. Subsequently, from the said 3D blank, in a drying or gas evolution process, at an elevated temperature, in particular moisture and gas inclusions are removed, thereby converting it into a 3D molded article. Thereby, the occurrence of cracks during the subsequent carbonization or graphitization of the 3D molded article in a furnace, under vacuum or a protective gas, such as argon or helium, for producing a 3D object can be avoided.

[0023] As the carbonizable or graphitizable organic material, preferably, carbon black, graphite powder, natural graphite, and starch, such as corn or potato starch or the like, or a mixture of some or all of these materials can be used.

[0024] In order to affect the strength or porosity of the finished carbonized or graphitized three-dimensional object, bamboo fibers, cotton fibers, hemp fibers, sisal fibers or other suitable plant fibers, or graphite fibers can be added to the carbonizable or graphitizable organic material while maintaining kneadability by adding, if necessary, yet another fluid binder or fluid organic substance until the desired consistency is achieved.

[0025] The shaping of the 3D blank can be carried out, for example, manually using a mold or in a mold, and in this case, the 3D blank is preferably removed from the mold before the drying process. In order to enable relatively easy demolding of the 3D blank, a mold made of Teflon (trademark) , silicone or other materials having limited elasticity can be used.

[0026] Alternatively, the 3D molded article is for removing the existing water to, in a drying process at room temperature or at a maximum of 100 °C SIt can be carried out. In the subsequent stabilization and homogenization process at a stabilization temperature of 140 °C in air or up to 450 °C under a protective gas or in a vacuum (at this time, a temperature of 250 °C is preferred), gas evolution occurs to avoid the occurrence of cracks during subsequent carbonization or graphitization.

[0027] The 3D molded article is appropriate during the stabilization or homogenization process Keep in the mold It is understood that it can be obtained.

[0028] The stabilization and homogenization of the 3D molded article can also occur while heating the furnace.

[0029] The stabilization of the 3D molded article is necessary to prevent its decomposition during carbonization / graphitization. Otherwise, the 3D molded article may melt or be greatly deformed. During stabilization, atoms / molecules reorganize, and as a result, they become resistant to high-temperature processes.

[0030] Furthermore, subsequently, the 3D molded article is carbonized in the furnace at a constant temperature of about 1,000 °C for the 3D object until pure carbon with various crystal structures is formed.

[0031] In another continuation of the present invention, then, the 3D molded article is graphitized in the furnace at a constant temperature of 2,000 °C or higher to form the 3D object.

[0032] Finally, the 3D molded article can be completely graphitized in the furnace at a temperature exceeding 2,500 °C for the formation of the 3D article.

[0033] It is understood that carbonization or graphitization needs to be carried out in the furnace under a protective gas to avoid the combustion of the organic components of the 3D blank.

[0034] Although it is indeed possible in principle to carry out carbonization or graphitization under a vacuum, in this case, there is a risk that volatile components may be accelerated due to the pressure difference between the inside of the 3D molded article and the vacuum, and cracks may occur.

[0035] For this reason, it is advantageous to apply high pressure inside the furnace so that volatile components are slowly diffused and released, thereby reliably avoiding cracks and damage.

[0036] Preferably, carbonization or graphitization is carried out at a heating rate of about 1°C / min until the desired temperature is achieved, followed by a temperature treatment for about 30 minutes, although temperature treatment for several hours is also possible.

[0037] To achieve uniform carbonization or graphitization, it is important to demold the 3D molded part beforehand.

[0038] In one particular aspect of the present invention, a kneadable compound may be mixed with metal powder or silicon powder so that metal carbide or silicon carbide is formed during high-temperature processing of a 3D molded product at >1,000°C under a protective gas.

[0039] Graphitized foamed 3D objects can also be converted into SiC 3D objects in a furnace at a temperature of >1,200°C and a pressure of approximately 30 mbar, using argon as a carrier gas to supply gaseous SiO.

[0040] This application relates to the invention described in the claims, but the disclosure of this application also includes: 1. A method for producing a carbonized or graphitized 3D object, comprising mixing a carbonizable or graphitizable material, made of carbon black, graphite powder, natural graphite, cellulose, or corn starch, or a mixture of some or all of these materials, with a fluid organic adhesive or a fluid thermoplastic organic substance to form a kneadable, dimensionally stable compound, and then applying Teflon to this compound. (trademark)Alternatively, the method is characterized by forming a 3D blank by molding using a silicone mold, removing the 3D blank from the mold, performing a subsequent drying and gas release process at room temperature or up to 100°C for a predetermined time, then performing a stabilization and homogenization process at a temperature from 140°C to a maximum of 450°C, and then manufacturing a 3D object by carbonizing or graphitizing the 3D blank in a furnace under a protective gas atmosphere, during which the temperature required for carbonization or graphitization is approached at a heating rate of 1°C / min, and then performing the temperature treatment. 2. The method according to 1., characterized in that bamboo fiber, cotton fiber, hemp fiber, sisal fiber, or graphite fiber is mixed into the material which can be carbonized or graphitized while maintaining its kneadability. 3. The method according to 1. or 2. above, characterized in that the 3D blank is formed by hand and / or using a template. 4. The method according to 3. above, wherein the 3D blank is stabilized and homogenized while the furnace is heated. 5. The method according to any one of 1. to 4. above, characterized in that a 3D molded product is carbonized under vacuum or protective gas at a constant temperature of 1,000°C until pure carbon having various crystalline structures is produced to form a 3D object. 6. The method according to any one of 1. to 5. above, characterized in that a 3D molded product is graphitized in a furnace at a constant temperature of 2,000°C or higher under vacuum or protective gas to form a 3D object. 7. The method according to 6., characterized in that a 3D molded product is completely graphitized in a furnace at a temperature exceeding 2,500°C under vacuum or protective gas to form a 3D object. 8. The method according to any one of 1. to 7. above, characterized in that argon or helium is used as a protective gas. 9. The method according to 7. or 8., characterized in that, after graphitizing a 3D molded product using a heating rate of approximately 1°C / min until the target temperature is achieved, a temperature treatment is performed for approximately 30 minutes to several hours. 10. The method according to any one of claims 1 to 9, characterized in that a metal powder or silicon powder is mixed into a kneadable compound, and as a result, a 3D molded article made of metal carbide or silicon carbide is produced when the 3D blank is subjected to high-temperature treatment at >1,000°C in a furnace under protective gas. 11. The method according to any one of claims 1 to 10 above, characterized in that a graphitized foamed 3D object is converted into a 3D object made of SiC in a furnace at a temperature of >1,200°C and a pressure of 30 mbar, while supplying gaseous SiO using argon as a carrier gas.

Claims

1. A method for manufacturing carbonized or graphitized 3D objects, - A carbonizable or graphitizable material made of carbon black, graphite powder, natural graphite, cellulose or corn starch, or a mixture of some or all of these materials, is mixed with a fluid organic adhesive or a fluid thermoplastic organic substance to form a kneadable, dimensionally stable compound. - This compound can be shaped by hand using an appropriate template to create a 3D blank, or it can be shaped in a mold and then removed from the mold to create a 3D blank. - The 3D blank is dried and gas released at room temperature or up to 100°C to be converted into a 3D molded product. - Stabilize and homogenize the 3D molded product in the mold, in air, under a protective gas, or under a vacuum, and at temperatures from 140°C to a maximum of 450°C. - Demolding the 3D molded product, and The method is characterized by manufacturing a 3D object by carbonizing or graphitizing the 3D molded product in a furnace under a protective gas atmosphere, wherein the heating rate approaches the temperature required for carbonization or graphitization at 1°C / min, and then performing the temperature treatment.

2. The method according to claim 1, characterized in that bamboo fiber, cotton fiber, hemp fiber, sisal fiber, or graphite fiber is mixed into the material which can be carbonized or graphitized while maintaining its kneadability.

3. The method according to claim 1, characterized in that the stabilization and homogenization of the 3D blank are performed while the furnace is being heated.

4. The method according to claim 1, characterized in that a 3D molded product is carbonized under vacuum or protective gas at a constant temperature of 1,000°C until pure carbon having various crystalline structures is produced to form a 3D object.

5. The method according to claim 1, characterized in that a 3D molded product is graphitized in a furnace at a constant temperature of 2,000°C or higher under vacuum or protective gas to form a 3D object.

6. The method according to claim 5, characterized in that a 3D molded product is completely graphitized in a furnace at a temperature exceeding 2,500°C under vacuum or protective gas to form a 3D object.

7. The method according to claim 1, characterized in that argon or helium is used as a protective gas.

8. The method according to claim 6, characterized in that graphitization of a 3D molded product is performed using a heating rate of approximately 1°C / min until the target temperature is achieved, and then a temperature treatment is performed for approximately 30 minutes to several hours.

9. The method according to any one of claims 1 to 8, characterized in that a metal powder or silicon powder is mixed into a kneadable compound, and as a result, a 3D molded product made of metal carbide or silicon carbide is produced when the 3D blank is subjected to high-temperature treatment at >1,000°C in a furnace under protective gas.

10. The method according to any one of claims 1 to 8, characterized in that a graphitized foamed 3D object is converted into a 3D object made of SiC in a furnace at a temperature of >1,200°C and a pressure of 30 mbar, while supplying gaseous SiO using argon as a carrier gas.