WO2016156384A1 - Procédé de fabrication d'une mousse nanostructurée ou microstructurée - Google Patents

Procédé de fabrication d'une mousse nanostructurée ou microstructurée Download PDF

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Publication number
WO2016156384A1
WO2016156384A1 PCT/EP2016/056901 EP2016056901W WO2016156384A1 WO 2016156384 A1 WO2016156384 A1 WO 2016156384A1 EP 2016056901 W EP2016056901 W EP 2016056901W WO 2016156384 A1 WO2016156384 A1 WO 2016156384A1
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Prior art keywords
foam
range
fibers
silicon carbide
mixture
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PCT/EP2016/056901
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German (de)
English (en)
Inventor
Siegmund Greulich-Weber
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Universität Paderborn
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Priority to EP16714351.0A priority Critical patent/EP3277646A1/fr
Publication of WO2016156384A1 publication Critical patent/WO2016156384A1/fr

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    • C04B38/00—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof
    • C04B38/0038—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof by superficial sintering or bonding of particulate matter
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    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/62227—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products obtaining fibres
    • C04B35/62272—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products obtaining fibres based on non-oxide ceramics
    • C04B35/62277—Fibres based on carbides
    • C04B35/62281—Fibres based on carbides based on silicon carbide
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    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
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    • C04B35/626—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B
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    • C04B35/626—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B
    • C04B35/63—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B using additives specially adapted for forming the products, e.g.. binder binders
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    • C04B38/00—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof
    • C04B38/0022—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof obtained by a chemical conversion or reaction other than those relating to the setting or hardening of cement-like material or to the formation of a sol or a gel, e.g. by carbonising or pyrolysing preformed cellular materials based on polymers, organo-metallic or organo-silicon precursors
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    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/34—Non-metal oxides, non-metal mixed oxides, or salts thereof that form the non-metal oxides upon heating, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
    • C04B2235/3409—Boron oxide, borates, boric acids, or oxide forming salts thereof, e.g. borax
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    • C04B2235/48—Organic compounds becoming part of a ceramic after heat treatment, e.g. carbonising phenol resins
    • C04B2235/483—Si-containing organic compounds, e.g. silicone resins, (poly)silanes, (poly)siloxanes or (poly)silazanes
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    • C04B2235/50—Constituents or additives of the starting mixture chosen for their shape or used because of their shape or their physical appearance
    • C04B2235/52—Constituents or additives characterised by their shapes
    • C04B2235/5208—Fibers
    • C04B2235/526—Fibers characterised by the length of the fibers
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    • C04B2235/52—Constituents or additives characterised by their shapes
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    • C04B2235/5264—Fibers characterised by the diameter of the fibers
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    • C04B2235/54—Particle size related information
    • C04B2235/5418—Particle size related information expressed by the size of the particles or aggregates thereof
    • C04B2235/5436—Particle size related information expressed by the size of the particles or aggregates thereof micrometer sized, i.e. from 1 to 100 micron
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    • C04B2235/78—Grain sizes and shapes, product microstructures, e.g. acicular grains, equiaxed grains, platelet-structures
    • C04B2235/781—Nanograined materials, i.e. having grain sizes below 100 nm
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B2203/00—Aspects relating to Ohmic resistive heating covered by group H05B3/00
    • H05B2203/017—Manufacturing methods or apparatus for heaters

Definitions

  • the present invention relates to a process for producing a nano- or microstructured foam.
  • the present invention further relates to a foam which may be made by such a method and which is composed of silicon carbide fibers.
  • Foams are known in various technical fields from the prior art. Foams can be characterized by a particularly reversible compressibility and thus by elastic properties. Conventionally, foams are produced using plastics such as polyurethane plastics, which can be foamed, for example, in the production to produce the foam structure.
  • the object is achieved according to the invention by a method for producing a nano- or microstructured foam with the features of claim 1.
  • the object is further achieved by a particular nano- or micro-structured foam with the features of claim 9.
  • the solution of the problem takes place Further, by a use with the features according to claim 14 or with the features according to claim 15.
  • a method for producing a nano- or microstructured foam is proposed, wherein the foam is constructed from a multiplicity of interconnected nano- or microstructured silicon carbide fibers.
  • the method comprises the method steps:
  • a foam can be represented in a particularly simple and cost-effective manner, wherein the foam by virtue of its formation of silicon carbide and in particular of silicon carbide fibers has particularly advantageous properties.
  • process described here can proceed completely or individually from process steps a) and b) and in particular b), preferably under protective gas, in particular argon.
  • the method according to method step a) comprises firstly providing a mixture with a silicon source and a carbon source, the silicon source and the carbon source being present together in particles of a solid granulate.
  • each of the particles of the solid granules may have a carbon source and a silicon source.
  • the silicon source and the carbon Source serve to be able to produce silicon carbide in the further process by a reaction of the carbon source with the silicon source.
  • the silicon carbide formed is present in particular in the form of nano- or microcrystalline fibers, which form the foam and are thus connected to one another via preferably a multiplicity of connection points.
  • these may in particular be structures in which the ratio of length to diameter is at least greater than or equal to 3: 1, whereas, in contrast to fibers in the case of particles, the ratio of length to diameter is less than 3: 1.
  • the ratio of length to diameter can also be greater than or equal to 10: 1, in particular greater than or equal to 100: 1, for example greater than or equal to 1000: 1.
  • the shaped silicon carbide fibers may be present in particular as 3C-SiC or in hexagonal form.
  • the silicon source and the carbon source should advantageously be selected such that they can form silicon carbide in the form of foams forming fibers in the conditions described below, in particular at the following temperatures, for example at normal pressure (lbar) by the method described above.
  • the silicon source may be pure silicon or silicon dioxide
  • the carbon source may be pure carbon
  • the solid particles may be formed, for example, by a sol / gel process, as described in detail below.
  • the solid particles may consist of silicon, carbon and optionally one or more dopants as described below, or at least for the most part, in a range of> 90% by weight.
  • the method further comprises treating the mixture provided in process step a) at a temperature in a range of> 1400 ° C to ⁇ 1500 ° C.
  • silicon carbide is allowed to form from the carbon source and from the silicon source of the solid granules.
  • the concrete shape of the silicon carbide produced can be controlled.
  • the temperature in process step b) to a range of> 1400 ° C to ⁇ 1500 ° C in particular at normal pressure (lbar)
  • nano-structured fibers of silicon carbide are formed in a particularly advantageous manner, wherein the silicon carbide especially in the form of monocrystalline 3C-SiC can form.
  • the temperature selected may allow the resulting fibers not to be present as separate fibers but rather as a foam.
  • a foam is in particular a body which has a plurality of individual fibers or fiber strands, each of the fibers or fiber strands having at least one, in particular a plurality of at least two, in particular at least three, Connecting hatches, which is respectively connected to at least one connection point of another fiber.
  • Connecting hatches which is respectively connected to at least one connection point of another fiber.
  • the formation of a temperature gradient may be advantageous, so that the material of the solid granules can pass into the gas phase at a position which has a comparatively higher temperature and silicon carbide fibers or a silicon carbide foam at the relatively lower temperature can be deposited, such as at a Abscheidoberober Diagram.
  • a release be provided scheideober Structure, which compared to the aforementioned temperature has a reduced temperature.
  • the temperature of the deposition surface may be reduced by a temperature that is in a range of> 30 ° C to ⁇ 100 ° C, for example 50 °, compared to the temperature generally set in the reactor in the aforementioned range of> 1400 ° C to ⁇ 1500 ° C.
  • Si 2 C and SiC 2 may already be present in the gas phase due to the intimate mixture, for example at the atomic level of silicon and carbon in the solid granules, resulting in easier formation of SiC at a different location in the temperature gradient leads. It can therefore be directly a Si-C gas, which may be present in a manner understandable to the skilled person, other gas components.
  • the silicon carbide produced is monocrystalline and thereby nano- or microcrystalline, and in detail a cubic 3C structure of the silicon carbide is made possible.
  • the silicon carbide (SiC) is a silicon carbide single crystal, preferably a monocrystalline cubic 3C-SIC
  • the monocrystalline silicon carbide fibers combine high thermal conductivity, which may be advantageous for certain applications, as described in detail below, as well as chemical and thermal durability, which is advantageous for long-term stability, with good properties of a foam.
  • hexagonal shapes of the silicon carbide are also conceivable within the scope of the present invention.
  • the molded product could be converted to the hexagonal form by a thermal treatment, for example to a range of about 2000 ° C.
  • a foam is produced, which is open-pored due to its construction of a fiber structure.
  • a variety of applications can be realized.
  • a foam in principle and also the foam produced by a method described above further characterized an elastic behavior.
  • the foam after a force from a certain restoring force and can thus return to its original form.
  • an elastic behavior can thus be achieved, which can further increase the field of application of the foam.
  • the foam can remain stable even after a large number of compressions and reliefs and, in particular, can not suffer any fiber break, thus retaining its properties, which indicates a high degree of longevity.
  • a solid and nevertheless flexible composite of the fibers or a fiber network is formed from the individual fibers by the connection in the region of the points of contact of individual or a plurality of fibers, without steps by means of textile processing, the fibers must be connected to each other. This further speaks for the simplicity of the method described here.
  • a nano-structured silicon carbide may be understood to mean, in particular, a silicon carbide which has a maximum spatial extent in the nanometer range, in particular of less than or equal to 100 nm, for example> 100 ⁇ m, the lower limit may be limited by the production method.
  • a microstructured fiber may in particular be a fiber which has a maximum spatial extent in the micrometer range, in particular of less than or equal to , ⁇ , for example> 100 nm, in at least one dimension.
  • the scaling and in particular the diameter and the length of the fibers can be determined by the temperature. at the growth site, the set temperature gradient and the time to grow the fibers.
  • silicon carbide fibers offer the advantage of high robustness and resistance to a variety of chemicals and conditions, such as aggressive media, such as acetone, acids or alkalis.
  • the method described here has the advantage that the foam produced here is highly resistant and also at high temperatures, optionally also with oxygen addition of well over 1000 ° C, such as to over 1100 ° C of oxygen and 1300 ° C in vacuo, or even stable if necessary.
  • a foam which can be formed by this method is also very robust against mechanical influences, so that no fiber breaks are to be expected even with a multiple compression.
  • SiC fibers usually have only a limited purity, such as residues of carbon.
  • the process described above makes it possible to produce highly pure silicon carbide fibers, which can further improve the properties of the foam and allow it to be defined in a very stable manner.
  • the method described above makes it possible to produce a large amount of foam in a comparatively short time, simply because of its simplicity.
  • the mixture provided in method step a) is provided using a sol-gel process.
  • a sol-gel process is to be understood in a manner known per se as such a process in which starting materials of the compound to be produced, the so-called precursors, are present in a solvent, this mixture being referred to as sol.
  • a so-called gel is formed by drying or aging, from which a solid can be formed by further treatment, in particular temperature treatment.
  • This solid can thus be defined by the selection of the precursors and contains the carbon source and the silicon source for the silicon carbide formation and can optionally also contain a dopant for doping the silicon carbide, which can already be added during the preparation of the sol.
  • the sol-gel process can also be carried out completely or at least partially in a protective atmosphere, in particular in an argon atmosphere.
  • the sol-gel process has at least the following method steps: c) providing a precursor mixture comprising a silicon precursor, a carbon precursor and optionally a dopant, wherein the precursor mixture is present in a solvent;
  • the precursors can first be provided, which are processed into a solid and can subsequently serve as carbon source or as silicon source, respectively, which are provided or used in method step a).
  • the choice of the silicon source or the carbon source or the silicon precursor and the carbon precursor is thus not fundamentally limited.
  • Preferred silicon precursors may include, for example, silicates, such as tetraethylorthosilicate (TEOS), whereas preferred carbon precursors may include sugars, such as sucrose, to form the solid particles provided as the source of carbon and silicon source in step a).
  • TEOS tetraethylorthosilicate
  • preferred carbon precursors may include sugars, such as sucrose, to form the solid particles provided as the source of carbon and silicon source in step a).
  • a mixture of liquid sugar and tetraethyl orthosilicate dissolved in ethanol may be provided as a mixture of carbon precursor and silicon precursor in process step c), the invention being understood to be not limited to the aforementioned examples.
  • the aforementioned size ranges have in particular process engineering advantages, such as preventing the increase of finer particles in a fiber production.
  • Such a particle size can be made possible, for example, by stirring during drying, wherein the particle size may be adjustable by the agitator used, a rotational speed and the duration or strength of the stirring, as is generally known in the art.
  • the dried precursor mixture is then optionally heated to a temperature in a range from> 800 ° C. to ⁇ 1200 ° C., in particular in a range from> 900 ° C. to ⁇ 1100 ° C., for example from 1000 ° C.
  • the solid produced can be freed from impurities in particular, which can make the silicon carbide produced particularly pure.
  • the quality of a generated fiber or a foam can be set particularly high and further defined.
  • crystallization of the silicon carbide from the gas phase can be improved.
  • step d) or optionally e) while the mixture according to step a) is provided or completed which can be formed by the above sol-gel process particles, each having a silicon source, such as pure silicon or silicon dioxide, and a carbon source , such as pure carbon.
  • a dopant during the sol-gel process, it may also be present in the particles, as described in detail below.
  • a mixture can be made possible on a quasi-atomic level, which significantly simplifies the production of silicon carbide.
  • a sol-gel process can be used in which the materials to be processed together form a mixture in the form of a gel and are then dried, and in a further step in a carbothermal reduction the crystallization of the silicon carbide, such as the growth of fibers, runs off.
  • the sol-gel process which is known per se as a process, offers a readily controllable and widely variable possibility of producing a wide variety of starting materials for the production of the fiber material according to the invention or of its starting materials.
  • process step b) proceeds in a reactor having a Abscheideoober Structure whose temperature is reduced relative to at least one other inner reactor surface.
  • a reactor having a Abscheideoober Structure whose temperature is reduced relative to at least one other inner reactor surface.
  • silicon carbide separates from the gas phase in the desired manner, in particular as a foam-forming fibers by providing a temperature gradient. Because the contact with the Abscheideoober Assembly can deposit silicon carbide directly from the gas phase, without the need for further funds.
  • the reactor may be configured by an upwardly open vessel, such as an upwardly open cylinder, in which the mixture is heated to the prescribed temperature in accordance with step a).
  • the, for example, circular and approximately rotatable deposition surface can be arranged approximately in the interior of the vessel or aligned therewith, so that the gas phase can come into contact with the deposition surface, whereby here the silicon carbide, for example in Form of nanoscale fibers or a foam formed therefrom, can separate.
  • a suitable particle size of the solid is set, as described above with respect to process step e).
  • a particle size arises which is in a range of> ⁇ to ⁇ 2mm, for example in a range of> 25 ⁇ to ⁇ 70 ⁇ to produce silicon carbide fibers or a foam formed therefrom.
  • the deposition surface may have a temperature which, at least in relation to at least one further inner reactor surface, has a temperature which is in the range of> 30 ° C. to ⁇ 200 ° C., preferably in the range of> 50 ° C to ⁇ 100 ° C, is reduced.
  • the deposition of a particular foam can be particularly effective, with such a temperature difference is also easily adjustable in terms of process technology.
  • the further inner reactor surface may be any surface located within the reactor, such as an inner wall or, in particular, a receiving surface for receiving the mixture.
  • the silicon carbide fibers are doped. This is possible by introducing a desired dopant into the fibers so as to enable electrical conductivity.
  • a mixture with a silicon source, a carbon source and a dopant can be provided, the silicon source, the carbon source and the dopant being present together in particles of a solid granulate.
  • the dopant this can be selected based on the desired doping.
  • the dopant (s) may in principle be chosen freely, for example in a production process of the solid granules be added as a soluble compound or about elementary, such as metallic, are added. Thus, the dopant may also be part of the solid granules according to process step a).
  • the doping of the forming silicon carbide such as forming fibers as 3C silicon carbide nanocrystals, as described in detail below, during the thermal treatment is carried out via the gas phase, especially if the Doping is carried out using a gaseous dopant in process step b).
  • doping materials phosphorus (P) or nitrogen (N) may preferably be used for n-type doping, or boron (B) or aluminum (Al) may be used for p-type doping.
  • the dopant as a gas in the Reactor can be given, wherein the mixture according to process step b) can form directly in the reactor before the temperature treatment.
  • the dopant may be present as a gas.
  • gaseous nitrogen can serve as a dopant.
  • the dopant is provided in the particles of the mixture according to method step a) when the doping materials are introduced into the wet-chemical part of the sol-gel synthesis, whereby the doping materials are introduced into the growing fibers during the thermal treatment Particles are incorporated.
  • the doping materials can be added here either as a soluble compound or metallic added.
  • the doping of the forming fibers is carried out during the thermal treatment via the gas phase.
  • Phosphorus (P) or nitrogen (N) or boron (B) or aluminum (AI) can in turn preferably be used as doping materials.
  • the silicon carbide fibers or the foam produced may have an extremely good electrical conductivity. This can further expand the field of application of the foam produced or of the components produced therefrom.
  • process step b) is carried out for a period in the range of> 30 s to ⁇ 10 min.
  • process step b) is carried out for a period in the range of> 30 s to ⁇ 10 min.
  • the time period used can be selected in a way which is obvious to the person skilled in the art as a function of further reaction parameters, such as the exact temperature.
  • the present invention further provides a foam, wherein the foam comprises a plurality of in particular nano- or microstructured fibers, wherein the fibers comprise silicon carbide, and wherein the fibers at least partially a plurality of at least two, in particular of at least three, connection points, wherein the connection points of a first fiber are each connected to at least one connection point of another fiber.
  • the foam is made up of a network of silicon carbide fibers, ie fibers having silicon carbide, which are each connected to other silicon carbide fibers via at least two, in particular at least three, connection points.
  • the foam can consist of silicon carbide fibers or silicon carbide fiber strands and / or the fibers can consist of silicon carbide.
  • the silicon carbide may be 3C-SiC.
  • the silicon carbide may be in hexagonal form.
  • a foam described above can in particular by the configuration of particular monocrystalline fibers of the crystal structure 3C-SiC in a particularly advantageous manner, the properties of a foam, namely a suitable elasticity or flexibility, combine with a high stability, in particular resistance to harsh conditions, such as comprehensive high Temperatures, aggressive media and high mechanical influences. As a result, the foam can be particularly durable for a large number of applications.
  • the silicon carbide fibers have a length of several millimeters and a thickness or a diameter in the nanometer range to micrometer range.
  • the silicon carbide fibers may be provided that the silicon carbide fibers have a length in a range of> 5mm to ⁇ 20mm.
  • the silicon carbide fibers have a thickness in a range of> 10 nm to ⁇ 2 ⁇ m. It has been found that, in particular, silicon carbide fibers with the parameters described above it can allow the foam formed to combine suitable elasticity with a high degree of robustness.
  • the foam has a porosity in a range of> 30% to ⁇ 80%, wherein the above-described values refer to the free, so not occupied by a Siliziumcarbidmaschine, volume with respect to the total volume.
  • porosities of the foam can also lead to the foam having particularly advantageous properties with regard to its elasticity or robustness.
  • the field of application can be increased.
  • these parameters may be adjustable, in particular by the chosen parameters of the manufacturing process. For example, by adjusting the temperature in the method step b) of the method described above or by a residence time of the fiber composite on a Abscheideoober Anlagen the formation of the foam, these properties of the foam forming fibers are influenced.
  • the foam is electrically conductive.
  • the field of application of the foam can be significantly increased compared to a non-doped foam.
  • the electrically conductive fibers 1 1 may have a conductivity of 0,0005 ⁇ ⁇ ⁇ ⁇ 1 to ⁇ lff'cm "1, for example,> ⁇ 0,005 ⁇ ⁇ ⁇ 1 to ⁇ ⁇ ⁇ ' ⁇ ⁇ ' 1
  • the silicon carbide fibers of the foam can be provided with a desired electrical conductivity in a particularly simple manner by doping, as described in detail above with respect to the method, for example by selection or amount of the dopant used.
  • the present invention further provides a use of a foam as described above for producing a heat-conducting element, an electrode, a seal, such as electrically conductive or electrically insulating, a filter, in particular an electrostatic filter, an absorber, in particular for high-frequency technology, a Flame retardant material, a catalyst, or a component for flame regulation, such as a gas burner, such as a component in Gasausström Suite, such as for gas burners.
  • the further processing of the pure foam to a prescribed component can for example take place in that the material is brought about by cutting into a desired shape and / or introduced into a suitable periphery.
  • the further processing may in principle comprise any suitable step which can finish the component in a manner known per se to a person skilled in the art, such as the provision of suitable structures, electrical connections or the like. This is in a manner understandable to the skilled person readily understandable depending on the specific shaped component.
  • the above-described foam comprising silicon carbide fibers of silicon carbide, for example of the crystal structure 3C-SiC
  • gaskets can be produced inexpensively even under extreme conditions, such as for high temperatures and aggressive media, and have a long service life.
  • thermally conductive elements or heat-conducting which may be electrically insulating or electrically conductive depending on the doping.
  • such an element can be used to connect a Heat source, such as a high-performance electronic element, with a heat sink.
  • the electrode it can be doped in particular and can also be resistant to aggressive media. Flame retardant materials, flame control materials, catalysts or absorbers can also be produced particularly advantageously by the method described above.
  • Fig. 1 A SEM image of a foam according to the present invention.
  • FIG. 1 shows an electron microscope (SEM) image of a foam according to the invention.
  • SEM electron microscope
  • the example described below relates to producing a foam configured of silicon carbide fibers using a sol-gel process to form the starting mixture.
  • sol-gel-Si-C precursor Preparation of the sol-gel-Si-C precursor: In the following, the chemical composition, sol-gel preparation with various drying steps at 70 ° C. to 200 ° C., as well as final recovery of the Si-C solid granules, are added 1000 ° C described.
  • Liquid sugar, tetraethyl orthosilicate and ethanol are mixed to form a sol and gelled at 60-70 ° C with exclusion of air.
  • the composition for one batch was (a) a colloidal suspension of 135 g of tetraethyl orthosilicate (TEOS) dissolved in 168.7 g of ethanol as a silicon source and (b) a solution of 68 g of sucrose as the carbon source in 75 g of distilled water containing 37.15 g of hydrochloric acid (HCl) is added as a catalyst for forming invert sugar. Subsequently, solution (a) was mixed with the liquid sugar (b) with stirring.
  • TEOS tetraethyl orthosilicate
  • HCl hydrochloric acid
  • liquid sugar invert sugar, 122g 70 ig
  • solution (b) can be used instead of solution (b) directly.
  • no water is added and only very little hydrochloric acid (5.2 g), since this is only needed to start the gelling process.
  • This sol is aged at 50 ° C and then dried at 150 - 200 ° C.
  • n-doping can be carried out with nitrogen (for example, additives: nitric acid, ammonium chloride, potassium nitrate or melamine) or with phosphorus (exemplary additives: potassium dihydrogen phosphate or di-sodium hydrogen phosphate).
  • a p-doping can be carried out by way of example with boron (exemplary additives: di-sodium tetraborate) or with aluminum (add .: aluminum powder).
  • the dopants are added to the sol, the amounts are dependent on the specific additive and the desired doping concentration.
  • the resulting solid is heated in a high-temperature reactor, wherein the granules in a temperature range of> 1400 ° C to ⁇ 1500 ° C in the gas phase passes and monocrystalline silicon carbide fibers in a temperature gradient on a rotating substrate or Depositing on a deposition surface cooler by about 50-100 ° C, wherein the fibers are bonded together to form a foam.

Abstract

La présente invention concerne un procédé de fabrication d'une mousse nanostructurée ou microstructurée, selon lequel la mousse est constituée d'une pluralité de fibres de carbure de silicium, en particulier nanostructurées ou microstructurées, reliées les unes aux autres. La présente invention est caractérisée en ce que ledit procédé comprend les étapes consistant à : a) préparer un mélange avec une source de silicium et une source de carbone, la source de silicium et la source de carbone se présentant ensemble sous forme de particules de granulat solide ; et b) traiter le mélange préparé à l'étape a) à une température supérieure ou égale à 1400 °C et inférieure ou égale à 1500 °C. Un tel procédé permet de produire, de manière simple et économique, une mousse constituée de fibres de carbure de silicium.
PCT/EP2016/056901 2015-03-31 2016-03-30 Procédé de fabrication d'une mousse nanostructurée ou microstructurée WO2016156384A1 (fr)

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WO2019063413A1 (fr) * 2017-09-29 2019-04-04 Psc Technologies Gmbh Procédé de production d'une couche sans azote, présentant du carbure de silicium
CN110831912A (zh) * 2017-06-27 2020-02-21 Psc科技股份有限公司 用于制造包含碳化硅的纤维和泡沫的方法及其用途
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CN112030544B (zh) * 2020-08-31 2021-06-15 北京航空航天大学 一种在碳化硅纤维表面原位生长碳化硅纳米线的方法

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DE102021128398A1 (de) 2021-10-30 2023-05-04 The Yellow SiC Holding GmbH Siliziumkarbidhaltiges Material, Präkursor-Zusammensetzung und deren Herstellungsverfahren

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