WO2021023761A1

WO2021023761A1 - Process for preparing a sic precursor material

Info

Publication number: WO2021023761A1
Application number: PCT/EP2020/071973
Authority: WO
Inventors: Siegmund Greulich-Weber
Original assignee: Psc Technologies Gmbh
Priority date: 2019-08-05
Filing date: 2020-08-05
Publication date: 2021-02-11
Also published as: DE102019121062A1; EP4168372A1

Abstract

The invention relates to a process for preparing a SiC precursor material suitable for producing silicium carbide-containing materials, in particular silicium carbide, specifically in high-energy processes.

Description

Process for the production of a SiC precursor material

The present invention relates to the technical field of the production of silicon carbide, in particular by means of high-energy processes.

In particular, the present invention relates to a method for producing a SiC precursor material which is suitable for producing silicon carbide-containing materials, in particular silicon carbide, preferably in high-energy processes such as selective synthetic crystallization.

The present invention further relates to an SiC precursor material for producing silicon carbide-containing materials, in particular silicon carbide.

In addition, the present invention relates to the use of an SiC precursor material in high-energy processes.

The present invention also relates to a method for producing silicon carbide-containing materials, in particular silicon carbide, from an SiC precursor material.

Last but not least, the present invention relates to materials containing silicon carbide, in particular silicon carbide, obtainable from an SiC precursor material.

Silicon carbide with the chemical formula SiC, also known under the name “Carborundum”, is a non-oxidic ceramic solid that has outstanding properties. In particular, the properties of silicon carbide have a high level of constancy up to temperatures of around 1,400 ° C. Among other things, silicon carbide is characterized by low density and thermal expansion, high hardness and thermal conductivity, good corrosion and wear resistance, which are also given at high temperatures and are accordingly expressed in the excellent dimensional stability of silicon carbide ceramics and components.

In addition, silicon carbide is toxicologically harmless and therefore, unlike many oxidic or metal-containing materials, not harmful to humans. Silicon carbide offers itself as a construction material and is traditionally used as an abrasive or is used in semiconductor technology, preferably in semiconductor electronics. Here, the properties of silicon carbide can be aligned and, in particular, optimized for the intended application by alloying or doping.

In addition, silicon carbide ceramics are ideal for demanding areas of application and challenging conditions, such as in chemical production. In addition, silicon carbide is also used as an insulator in high-temperature reactors.

Silicon carbide-containing materials are usually obtained by sintering processes from starting materials or starting material mixtures which contain silicon carbide particles. However, this results in relatively porous structures or bodies which are only suitable for a limited number of fields of application. Furthermore, the properties of these porous silicon carbide structures or bodies do not correspond to those of compact crystalline silicon carbide, so that the advantageous properties of silicon carbide in particular are not fully exploited by sintering processes.

Structures made of inorganic materials can also be produced by means of high-energy processes, such as selective synthetic crystallization, in which the starting materials or precursors used react or sublime due to a high input of energy.

In principle, the selective synthetic crystallization processes enable rapid implementation and the production of inorganically based structures or bodies. At the same time, the use of the corresponding high-energy processes is associated with a number of challenges for both the precursor and the product materials. Precursor materials have to react in a predetermined manner when exposed to energy and in particular disruptive side reactions have to be excluded. In addition, it must be possible to rule out segregation or phase separation or decomposition of the resulting products due to the high energy exposure.

In the case of silicon carbide, this is made more difficult by the fact that silicon carbide is in the range at high temperatures, depending on the respective crystal type between 2,300 and 2,700 ° C does not melt, but sublimates, ie changes from the solid directly to the gaseous state of aggregation.

Silicon carbide is therefore not suitable, or only suitable to a very limited extent, as a starting material in high-energy processes for the efficient production of corresponding inorganically based structures or bodies. Because of the versatility of silicon carbide and the large number of positive application properties, approaches that overcome this disadvantage are of great interest. An efficient possibility of producing silicon carbide-containing materials or bodies consists in the use of suitable precursor compounds or materials which react to silicon carbide or silicon carbide-containing materials under the action of energy. DE 10 2015 100 062 A1, for example, describes a method for producing silicon carbide-containing materials, in particular silicon carbide crystals or fibers, which are obtained by deposition from the gas phase. For this purpose, a precursor granulate is used as the starting material, which is obtained by a sol-gel process and then subjected to a thermal treatment at over 1,000 ° C.

In addition, additive manufacturing processes for the direct manufacture of objects containing silicon carbide from suitable precursor materials are known, for example from DE 10 2015 105 085 A1, DE 10 2017 110 362 A1, DE 10 2017 110 361 A1 or also DE 10 2018 127 877.2

DE 102015 105 085 A1 describes a method for producing bodies from silicon carbide crystals, the silicon carbide being obtained in particular by laser irradiation of precursor materials containing suitable carbon and silicon. Under the action of the laser beam, the precursor materials decompose selectively and silicon carbide is formed without sublimation processes occurring.

However, the reproducible representation of the precursor material according to DE 10 2015 105 085 A1, which is obtained via a sol-gel process, is lengthy and complex. The aging of the compounds used from a sol to a gel is initially very time-consuming. In addition, from the Sol-gel process, the product obtained by simple drying has changing compositions, since, inter alia, the solvents and acids that are necessarily used remain in part in the dried product, these being prone to side reactions, particularly at higher drying temperatures and thermal aftertreatment. A complex reductive thermal treatment at high temperatures is therefore required in order to finally bring about a conversion into a stable and reproducible precursor material form.

In contrast, DE 102018 127877.2 describes an optimized process that allows a defined, uniformly composed SiC precursor granulate to be obtained reproducibly by first homogenizing or dissolving the individual components or starting materials of the granulate composition in a preferably colloidal solution or dispersion. This is followed by the rapid removal of the solvent or dispersant, since it has been shown that aging of the colloidal solution to form a gel, as described in DE 102015 105085 A1, is not necessary. Likewise, in the context of the method according to DE 102018 127 877.2, the complex thermal treatment at temperatures of over 1,000 ° C. can be dispensed with and in this way a significant saving in time and energy can be achieved, which reduces the costs for the production of an SiC precursor granulate , can be significantly reduced.

DE 10 2017 110 362 A1 relates to the production of objects containing silicon carbide, in particular from silicon carbide alloys, starting from powdered precursor materials by means of what is known as selective synthetic crystallization.

The selective synthetic crystallization relates in detail to high-energy processes for the production of silicon carbide and silicon carbide alloys, preferably by means of additive manufacturing. Selective synthetic crystallization includes processes which are based on laser deposition welding, as described in DE 10 2018 128 434.9, for example, selective laser melting, such as in the

DE 10 2017 110 362 A1, or inkjet printing methods, as known, for example, from DE 10 2017 110 361 A1, are based and in which a silicon carbide-containing material is successively produced from an SiC precursor material through a targeted energy input, in particular a location-selective energy input Object is created. The prior art lacks a simple process that provides suitable compositions, in particular suitable SiC precursor materials, which can be used to produce silicon carbide, in particular silicon carbide-containing materials, in high-energy processes based on selective synthetic crystallization.

The present invention is therefore based on the object of eliminating the aforementioned disadvantages associated with the prior art, or at least reducing them.

In particular, one object of the present invention is to provide a simplified, efficient method for producing an SiC precursor material which can be used to produce silicon carbide-containing materials, in particular silicon carbide.

A further object of the present invention is to provide a SiC precursor material which can be produced reproducibly with controllable quality. A further object of the present invention is to provide a method for producing silicon carbide-containing materials, in particular silicon carbide, from an SiC precursor material which is advantageous in terms of its implementation compared to the methods described in the prior art. Finally, it is an object of the present invention to provide silicon carbide-containing materials, in particular silicon carbide, obtainable from an SiC precursor material.

The subject matter of the present invention according to a first aspect of the present invention is thus a method for producing an SiC precursor material according to claim 1; further advantageous refinements of this aspect of the invention are the subject matter of the relevant subclaims.

Another object of the present invention according to a second aspect of the present invention is an SiC precursor material according to claim 13; further advantageous refinements of this aspect of the invention are the subject matter of the relevant subclaims. In addition, according to a third aspect of the present invention, the present invention further relates to the use of an SiC precursor material according to claim 17.

Yet another subject matter of the present invention according to a fourth aspect of the present invention is a method for producing silicon carbide, in particular silicon carbide-containing materials, from an SiC precursor material according to claim 18; further advantageous refinements of this aspect of the invention are the subject of the related sub-claim.

Finally, according to a fifth aspect of the present invention, the present invention further provides silicon carbide, in particular silicon carbide-containing materials, obtainable from an SiC precursor material according to claim 20.

It goes without saying that the special configurations mentioned below, in particular special embodiments or the like, which are only described in connection with the aspect of the invention, also apply accordingly in relation to the other aspects of the invention, without this needing to be explicitly mentioned.

Furthermore, with all of the relative or percentage, in particular weight-related, quantitative data mentioned below, it should be noted that these are to be selected by the person skilled in the art within the scope of the present invention in such a way that the sum of the ingredients, additives or auxiliary substances or the like always 100% or 100 % By weight result. This goes without saying for the expert.

In addition, it applies that all of the parameter data or the like mentioned below can in principle be determined or determined using standardized or explicitly stated determination methods or determination methods that are known per se to the person skilled in the art.

Having said that, the subject matter of the present invention is explained in more detail below.

The subject of the present invention - according to a first aspect of the present invention - is thus a method for Fierstellung a SiC- Precursor materials, where elemental silicon is mixed with at least one organic carbon compound.

Because, as the applicant has surprisingly found, SiC precursor materials can be produced from elementary silicon and at least one organic carbon compound efficiently and reproducibly with constant quality, which allow the production of silicon carbide in high-energy processes. In particular, a combination of silicon powder and saccharides, in particular sugars, makes it possible to produce inexpensive and highly pure precursor materials in a particularly simple and easily reproducible manner. In particular, composite particles with a core-shell structure, in particular a silicon core and a shell made of sugar, are also accessible in this way.

The method according to the invention allows the provision of a large number of SiC precursor materials from which a wide variety of silicon carbide-containing materials can then be produced.

In the context of the present invention, a silicon carbide-containing material is to be understood as meaning a binary, ternary or quaternary inorganic compound or alloy whose empirical formula contains silicon and carbon. In particular, within the scope of the present invention, a silicon carbide-containing compound does not contain any molecularly bound carbon, such as, for example, carbon monoxide or carbon dioxide; rather, the carbon is in a solid structure. The method according to the invention also ensures that silicon carbide-containing material or silicon carbide can be reliably obtained from the SiC precursor material by means of methods that can be carried out efficiently. The composition of the SiC precursor material allows a method to be carried out which provides temperatures in the context of silicon carbide production which are safely below the sublimation limit of silicon carbide. Thus, by means of methods that are more energy-efficient in comparison with the prior art, silicon carbide can be obtained reliably and with little effort for a variety of purposes from an SiC precursor material that can be produced in an uncomplicated manner. A significant advantage of the method according to the invention is that the elemental silicon used can be obtained from easily accessible sources. In particular, it is possible to make elemental silicon to use reusable raw material sources and / or excess material residues from silicon processing by simply processing them for use in the method according to the invention. For this purpose it is preferably completely sufficient if the reusable raw material sources and / or excess material residues are brought into a powdery, advantageously particulate, initial form, which can generally be easily achieved by generally known comminution processes. Overall, therefore, the preparation of the elemental silicon for the method for producing the SiC precursor material can be carried out particularly easily.

By choosing the respective material source, the quality of the elemental silicon used can also be traced and ensured, so that the SiC precursor material can be produced in a reproducible manner and with constant quality. In addition, the purity of the silicon and thus ultimately also of the silicon carbide-containing materials obtained with the precursor materials can be determined by the selection of the respective reference source, whereby silicon carbide-containing materials can be provided for a wide variety of applications under respectively optional economic conditions. Furthermore, the method according to the invention, in that it starts from reusable raw material sources and / or excess material residues, represents an advantageous, since value-adding, further use of elemental silicon. For example, elemental silicon can be used for the production of the SiC precursor material from the production of silicon wafers or Solar cells are purchased, ie the material leftovers can easily be removed from the respective manufacturers. This aspect of the further use of a raw material that is qualitatively flawless, but initially in excess, is a particular example of a value-adding further use of material residues and also has a positive effect on the cost efficiency of the method according to the invention.

It is now preferred within the scope of the present invention that the elemental silicon is used in the form of a powder, in particular in the form of a microscale powder, preferably in the form of a nanoscale powder. In addition, it has preferably proven useful if the elemental silicon is used in the form of particles, in particular in the form of microparticles, preferably in the form of nanoparticles. In this context it is particularly preferred if the elementary silicon is used in the form of monocrystalline particles, in particular in the form of monocrystalline microparticles, preferably in the form of monocrystalline nanoparticles.

The use of the elemental silicon in the powdery, in particular particulate, nature mentioned favors the homogeneous distribution of the elemental silicon in the SiC precursor material according to the invention. A homogeneous distribution of the material components enables the efficient implementation of the SiC precursor material in high-energy processes, in particular also with brief exposure to high temperatures, as is the case with laser-based processes. Furthermore, it is preferably provided that the elementary silicon is obtained from reusable raw material sources and / or comes from excess material residues from silicon processing.

Particularly good results are obtained when the elemental silicon, in particular the elemental silicon from reusable raw material sources and / or excess material residues from silicon processing, is comminuted, in particular crushed, preferably ground.

Reusable raw material sources and / or excess material residues from silicon processing are understood in the context of the present invention to mean, for example, excess material from silicon wafer production or solar cell production. In addition, it is also possible, for example, to recycle silicon-containing solar cells that are no longer used. These excess materials can then advantageously be collected and processed in the context of a flomogenization process for use in producing the SiC precursor material.

The use of elemental silicon from the sources described has the great advantage that the quality of the elemental silicon used is reliably ensured. At the same time, it can be assumed that both the SiC precursor material and the silicon carbide produced therefrom are largely free of undesirable impurities and by-products. In the context of the present invention, it is now further preferred if elemental silicon with a degree of purity of at least 95%, in particular at least 98%, preferably at least 99%, preferably at least 99.5%, is used. This makes it possible on the one hand to obtain highly pure and defined silicon carbide ceramics, on the other hand it is also possible to produce silicon carbides with specific and preselected electrical properties.

In the context of the present invention it is provided that the elemental silicon is mixed with at least one organic carbon compound. In this context, an organic carbon compound is understood to be a compound that is composed predominantly of the elements carbon, hydrogen and oxygen. However, to a small extent, other heteroatoms such as nitrogen, sulfur or phosphorus can also be contained in the organic carbon compound, these heteroatoms only being desirable if doping of the silicon carbide is to be achieved.

With regard to the form of the organic carbon compound, it is preferably provided within the scope of the present invention that it is used in liquid form.

This means that the organic carbon compound, if it is present as a solid, is first brought into solution and then used for the method for producing the SiC precursor material. If the organic carbon compound is already present as a liquid or at least essentially in liquid form, it is used as such directly for the production process. In this context, the organic carbon compound can in particular be present in a liquid or in the form of a liquid solution or dispersion which contain the organic carbon compound, as explained below. The organic carbon compound in liquid form is preferably suitable for forming a homogeneous dispersion with the elemental silicon, in particular in the form of a nano- or microscale powder.

Furthermore, it is preferably provided that the organic carbon compound is a polymer or an oligomer or monomer. In the context of the present invention, a monomer is generally understood to be a low molecular weight, reactive molecular unit which can be converted in polyreactions to form higher molecular weight compounds such as oligomers or polymers. In the context of polyreactions, structurally identical or structurally similar, at least similarly reactive, monomers are linked to one another via reactive groups such as multiple bonds or functional groups and thus form the basic units of an oligomer or polymer. Exemplary polyreactions can be polycondensations, polyadditions and radical or coordinative polymerizations, without wishing to limit the type of possible polyreactions by this list.

In the context of the present invention, an oligomer is understood to mean a molecule that results from monomers reacted with one another in a polyreaction. For the purposes of the invention, an oligomer is composed of at least two monomer units. These monomer units can be the same or different, so that homooligomers or heterooligomers are obtained. As a rule, it is provided that, within the scope of the invention, oligomers have a definable number of repeating units, in particular between two and 50 repeating units.

In the context of the present invention, polymers are understood as meaning macromolecular compounds which are built up in a polyreaction from one or more different monomers. The term polymer therefore includes both homopolymers and heteropolymers; Homopolymers are obtained by reacting the same monomers and heteropolymers are obtained by reacting different monomers. Furthermore, polymers can have a relatively broad distribution of the monomeric repeating units. Overall, polymers within the meaning of the invention are characterized by a number of monomer units that is difficult to define and have high average molecular weights.

If the organic carbon compound is a polymer or oligomer, the organic carbon compound is preferably characterized in that the polymer or oligomer is selected from the group of polyethers, polyethylene glycols, polysaccharides, polyketones, polyether ketones, polyesters, polycarbonates, polyhydroxyalkanoates and mixtures thereof , in particular polyethers, polysaccharides, polyesters, polycarbonates and their mixtures, is preferably a polysaccharide. If the organic carbon compound is a monomer, it has proven useful if the monomer is a monomer for producing the aforementioned polymers or oligomers, in particular selected from the group of ethers, saccharides, esters, carbonates, carboxylic acids and mixtures thereof, preferably a saccharide is.

It is particularly preferred in the context of the invention if the organic carbon compound, in particular the polymer or oligomer, has ether, carbonyl, acetal, ester and / or carbonate repeat units.

Organic carbon compounds of the aforementioned nature and composition show in the context of the present invention an advantageous mixing behavior with the elemental silicon in the course of the production of the SiC precursor material and excellent properties in the production of silicon carbide in the context of high-energy processes from the SiC precursor material , since they contain in particular carbon, hydrogen and oxygen and thus possibly form by-products which are preferably highly volatile and do not reduce the quality of the silicon carbide produced. Furthermore, within the scope of the present invention it can preferably be provided that the one organic carbon compound, in particular the polymer or oligomer or monomer, is linear and / or branched and / or cyclic. Branched or cyclic monomers can occur in particular when using sugars or other substances that can react to form oligomers or polymers.

In addition, it is preferred if the organic carbon compound, in particular the polymer or oligomer or monomer, has functional groups, in particular hydroxyl groups, in addition to the repeating units.

According to a preferred embodiment, the organic carbon compound is present as a heterogeneous mixture, in particular as a heterogeneous mixture of monomers and monomer condensate, preferably as a heterogeneous mixture of monomer and dimeric, oligomeric or polymeric monomer condensate. In particular, it is particularly preferred in the context of the present invention if the organic carbon compound, in particular the polymer or oligomer or monomer, is a polyalcohol. In this context it is very particularly preferred if the polyalcohol is a saccharide.

In the context of a particularly preferred embodiment of the present invention, it has proven advantageous if the saccharide is selected from the group of hexoses or pentoses or mixtures thereof.

The use of saccharides as a special form of the organic carbon compound is characterized in particular by the fact that saccharides have an advantageously balanced ratio between carbon, hydrogen and oxygen in the context of the present invention and thus in the context of the production of silicon carbide from the SiC precursor according to the invention - show ideal reaction behavior. Above all, it should be emphasized here that saccharides enable the formation of particularly pure silicon carbide, since apart from carbon only volatile by-products are released, in particular water.

In the context of the present invention, it has proven useful if the saccharide is selected from the group of glucose and its stereoisomers, fructose and its stereoisomers, xylose and its stereoisomers, the disaccharides of the aforementioned compounds, in particular glucose and / or fructose, preferably the glucose and fructose, the oligosaccharides of the aforementioned compounds, in particular glucose and / or fructose, the polysaccharides of the aforementioned compounds, in particular glucose or mixtures thereof.

It is also preferably provided here if the saccharide is in the form of a liquid, in particular in the form of a syrup, preferably in the form of a highly concentrated syrup. In the context of the present invention, a highly concentrated syrup is understood to mean an aqueous solution of the saccharide with a water content of less than 25% by weight, based on the total amount of the syrup. Watery Saccharide solutions with a water content equal to or greater than 25% by weight are regarded as syrup.

According to a further, very particularly preferred embodiment of the present invention, it has proven to be particularly advantageous if the saccharide is invert sugar syrup.

Invert sugar syrup in the context of the invention means an aqueous solution of sucrose or starch which has been partially inverted by hydrolysis. Usually the invert sugar syrup in this connection can contain varying proportions of the glucose and fructose obtained by partial hydrolysis. These proportions are preferably between 5 to 95% for glucose and accordingly between 95 to 5% for fructose, based on the total amount of monosaccharides in the invert sugar syrup. This is because it has been found for this special embodiment that elemental silicon can be mixed so well with invert sugar syrup that a particularly homogeneous distribution of elemental silicon in powder or particle form can be achieved. This forms the ideal prerequisites for the production of a uniformly composed, reproducible and controllable high-quality SiC precursor material from which silicon carbide can subsequently be produced efficiently and reliably.

Usually it is provided within the scope of the present invention that the mixture of elemental silicon and organic carbon compound is in the form of a dispersion.

In the context of the present invention, a dispersion is to be understood as an at least two-phase system, a first phase, namely the dispersed phase, being present in a distributed manner in a second phase, the continuous phase.

In this case it has proven useful if the dispersion contains a dispersant. In the context of the present invention, it is preferred if the dispersant is selected from water, organic solvents and / or mixtures thereof.

It is particularly preferred in this context if the organic solvent is selected from alcohols, esters, ketones, amines, amides, sulfoxides and mixtures thereof, in particular methanol, ethanol, 2-propanol, acetone, ethyl acetate, / V, / V-dimethylformamide, dimethyl sulfoxide and mixtures thereof.

It can also preferably be provided that to produce the mixture of elemental silicon and organic carbon compound, in particular polymer or oligomer or monomer, both components are mixed, in particular mixed, preferably stirred, in the presence of a dispersant. In this context, it has preferably proven useful if the mixture or dispersion of elemental silicon and organic carbon compound, in particular polymer or oligomer or monomer, is homogeneously distributed.

In the context of the present invention, the homogeneous distribution of components in a mixture or dispersion is understood to mean that these components are present within the mixture or dispersion in such a way that a very similar, preferably identical, composition of the components is found throughout the mixture or dispersion becomes. Similarly, in the context of the present invention, the term homogeneous particles is understood to mean that particles are present which are characterized by at least essentially the same properties such as size, density, nature or chemical composition. In addition, it is preferable if the dispersion of elemental silicon and organic carbon compound, in particular polymer or oligomer or monomer, is converted into a powder, in particular a precursor powder, by drying, in particular afterwards. In this context, it is further preferred that with the supply of heat and / or reduction in pressure, in particular with supply of heat and reduction in pressure, and / or stirring, preferably with supply of heat and reduction in pressure and stirring, into a powder , in particular a precursor powder, is transferred.

This procedure is characterized by the fact that, as part of the conversion into a powder, a particularly homogeneous distribution and thorough mixing of the Components, ie of elemental silicon and the at least one organic carbon compound, is achieved.

It has proven to be particularly preferred here if, for the production of the SiC precursor material, the dispersion of elemental silicon and organic carbon compound, in particular polymer or oligomer or monomer, is carried out

(i) mixing, in particular mixing, preferably stirring, optionally in the presence of a dispersion medium, and,

(ii) is optionally converted downstream into a powder, in particular a precursor powder, by drying.

In addition, it is very particularly preferred if, for the production of the SiC precursor material, the dispersion of elemental silicon and organic carbon compound, in particular polymer or oligomer or monomer, is carried out

(iii) mixing, especially blending, preferably stirring, optionally in the presence of a dispersion medium, and,

(iv) optionally with the supply of heat and / or reduction of the pressure, in particular with the supply of heat and reduction of the pressure, preferably with the supply of heat and reduction of the pressure and stirring, downstream into a powder, in particular a precursor powder.

Furthermore, it has proven to be advantageous to convert the SiC precursor material into a powder, in particular a microscale powder, preferably a nanoscale powder, by comminuting, in particular crushing, preferably grinding, preferably grinding.

In general, it is preferably provided within the scope of the present invention that the SiC precursor material is available as a precursor powder, in particular as a granular precursor powder, or as a precursor dispersion, in particular as a solid-in-liquid precursor dispersion.

In this context, it is further preferred if the precursor powder or the precursor dispersion consists of homogeneous particles, in particular microparticles, preferably consists of or contains nanoparticles, preferably consists of them.

In the context of a preferred embodiment of the present invention, it has proven to be advantageous if the precursor powder or the precursor dispersion consists of composite particles, in particular homogeneous composite particles, preferably composite particles with a core-shell structure (core-shell structure), or contains these , preferably consists of this. In the context of the present invention, composite particles with a core-shell structure (core-shell structure) are generally understood to mean particles which have an inner core and an outer shell. The inner core can for example be formed by the elementary silicon, so that the outer shell is formed by the at least one organic carbon compound.

In particular, when the SiC precursor material according to the invention is present as a precursor powder, in particular as a granular precursor powder, a particularly preferred embodiment of the present invention provides for the SiC precursor material to be composed of homogeneous particles, in particular microparticles, preferably nanoparticles , and these particles are preferably composite particles, in particular homogeneous composite particles, preferably composite particles with a core-shell structure (core-shell structure), or contain them.

For these composite particles, it was observed in particular that a homogeneous size distribution within the particles, on the one hand, and a homogeneous component distribution with regard to the elemental silicon and the at least one organic carbon compound, can ideally be achieved through core-shell structures.

Accordingly, SiC precursor materials composed in this way, in particular precursor powder composed in this way, are characterized by an overall high level of homogeneity. In the context of the production of silicon carbide in high-energy processes, this circumstance allows particularly good conversions and the formation of silicon carbide with a particularly uniform composition in relation to the quantitative ratio between carbon and silicon. In the context of the present invention, particularly good results are now obtained for the powdery, in particular particulate, SiC precursor material if the powder has particle sizes in the range from 0.1 μm to 1,500 μm, in particular 0.1 μm to 1,000 μm, preferably 0, 5 pm to 800 pm, preferably 1 pm to 600 pm.

The use of SiC precursor materials, which are present in the form of precursor powders, in particular particles, preferably in the form of composite particles, preferably composite particles with a core-fill structure, also make it possible to control the composition of the silicon carbide produced in advance by simply the quantitative ratio between elemental silicon and the at least one organic carbon compound is varied. As stated above, within the framework of a further, preferred alternative embodiment of the present invention, it can be provided that the SiC precursor material is obtainable in the form of a precursor dispersion, in particular in the form of a solid-in-liquid precursor dispersion. It is very particularly preferred if the precursor dispersion is in the form of an SiC precursor sol, for the production of silicon carbide-containing materials, in particular silicon carbide of the aforementioned nature.

With regard to the selection of the solvent or dispersant for the SiC precursor material in the form of a solution or dispersion, in particular in the form of an SiC precursor sol, this can be selected from all suitable solvents or dispersants.

Usually, and if the organic carbon compound itself is not in liquid form, the dispersant is selected from water and organic solvents and their mixtures. The organic carbon compounds used and the elemental silicon should have sufficiently high solubilities or high dispersibility in the solvents used, in particular in ethanol and / or water, in order to be able to form finely divided dispersions or solutions, especially sols. The SiC precursor components should also not react with other constituents of the dispersion, in particular the sol, to form insoluble compounds during the production process. About that In addition, the individual components should be distributed as homogeneously as possible in the dispersion.

In the context of the present invention it can preferably be provided that the organic dispersant is selected from alcohols, in particular methanol, ethanol, 2-propanol, acetone, ethyl acetate and mixtures thereof. It is particularly preferred in this context if the organic dispersant is selected from methanol, ethanol, 2-propanol and mixtures thereof, with ethanol being particularly preferred.

The above-mentioned organic dispersants are miscible with water over a wide range and in particular are also suitable for dispersing polar inorganic substances. As stated above, in the context of the present invention, mixtures of water and at least one organic dispersant, in particular mixture of water and ethanol, are preferably used as the dispersant. In this context, it is preferred if the dispersant has a weight ratio of water to organic solvent of 1:10 to 20: 1, in particular 1: 5 to 15: 1, preferably 1: 2 to 10: 1, preferably 1: 1 to 5: 1, particularly preferably 1: 3.

The amount in which the composition contains the dispersant can vary within a wide range depending on the particular application conditions and the type of silicon carbide-containing compound to be produced. The composition usually has dispersants in amounts of 10 to 80% by weight, in particular 15 to 75% by weight, preferably 20 to 70% by weight, preferably 20 to 65% by weight, based on the composition. As far as the viscosity of the SiC precursor material in the form of a precursor dispersion, in particular in the form of a solid-in-liquid precursor dispersion, preferably in the form of an SiC precursor sol, is concerned, this can vary within wide ranges in view of the respective application conditions and the structures to be produced .

It has proven useful if the SiC precursor material is in the form of a precursor dispersion, in particular in the form of a solid-in-liquid precursor dispersion, preferably in the form of an SiC precursor sol, has a dynamic Brookfield viscosity at 25 ° C. in the range from 3 to 500 mPas, in particular 4 to 200 mPas, preferably 5 to 100 mPas. In the context of the present invention, it is therefore preferred if highly viscous SiC precursor materials in the form of a precursor dispersion, in particular in the form of a solid-in-liquid precursor dispersion, preferably in the form of an SiC precursor sol, which are suitable for spray or print application, can be used, as in this way even towering structures are accessible to a certain extent without support structures.

A very particularly preferred embodiment of the present invention provides, in particular, a precursor dispersion which is composed of elemental silicon and a carbon compound which is in the form of a liquid, in particular in the form of a syrup, preferably in the form of a boiling-centered syrup. In this preferred case, an advantageous, since it is easy to adjust and stable, homogeneous distribution of the components in the precursor dispersion is achieved. Above all, in the context of this particular, preferred alternative of the present invention, it has proven to be very suitable if the elemental silicon is mixed with invert sugar syrup. A stable, highly viscous precursor dispersion is obtained from Flieraus, which can be processed easily, safely and specifically in the selective synthetic crystallization, applied as an inket process. Above all, such a highly viscous and stable, homogeneous precursor dispersion allows reliable application of the SiC precursor material in uniform layers with good meterability, so that a particularly good and simple implementation and high reproducibility of the silicon carbide production can be guaranteed. With regard to the nature and composition of the SiC precursor material, this can vary within wide ranges and depending on the intended nature of the desired silicon carbide. For the production of stoichiometric silicon carbide, it has now proven itself within the scope of the present invention if there is an at least essentially stoichiometric silicon-to-carbon ratio between the elemental silicon and the organic carbon compound, in particular polymer or oligomer or monomer, in the SiC precursor material, in particular a silicon-to-carbon ratio in the range from 35:65% by weight to 65:35% by weight, preferably 40:60% by weight to 60:40% by weight, preferably 45:55% by weight to 55:45% by weight, particularly preferably 50:50 % By weight, based on the SiC precursor material. In the context of the present invention, a stoichiometric silicon carbide or silicon carbide-containing material is to be understood as a material which contains carbon and silicon at least essentially in a molar silicon-to-carbon ratio in a range around 1: 1. For example, non-stoichiometric silicon carbide can also be easily produced. In the context of the present invention, a non-stoichiometric silicon carbide is to be understood as meaning a silicon carbide which does not contain carbon and silicon in a molar ratio of 1: 1. In the context of the present invention, a non-stoichiometric silicon carbide usually has a molar excess of silicon.

If, within the scope of the present invention, a non-stoichiometric silicon carbide is or is to be produced with the SiC precursor material, the non-stoichiometric silicon carbide is usually a silicon carbide of the general formula (I)

SiC-i- _x (I) with x = 0.05 to 0.8, in particular 0.07 to 0.5, preferably 0.09 to 0.4, preferred

0.1 to 0.3.

Such silicon-rich silicon carbides have a particularly high mechanical strength and are suitable for a large number of applications as ceramics.

If a non-stoichiometric silicon carbide is produced with the SiC precursor material, the SiC precursor material usually contains (A) the silicon source in amounts of 60 to 90% by weight, in particular 65 to 85

% By weight, preferably 70 to 80% by weight, and

(B) the carbon source in amounts of 10 to 40% by weight, in particular 15 to 35% by weight, preferably 20 to 30% by weight, each based on the SiC precursor material.

In general, SiC precursor materials, which are intended to be used to produce non-stoichiometric silicon carbide or material containing silicon carbide, have a comparatively higher proportion of elemental silicon than the organic carbon compound. In this connection, it has preferably proven useful if a silicon-to-carbon ratio between the elemental silicon and the organic carbon compound, in particular polymer or oligomer or monomer, in the range of 65:35% by weight to 85:15% by weight in the SiC precursor material. %, preferably 70:30% by weight to 80:20% by weight, preferably 72:28% by weight to 78:22% by weight, based on the SiC precursor material.

It is also possible within the scope of the present invention to put together the SiC precursor material in such a way that the silicon carbide-containing compound produced contains a silicon carbide alloy or is a silicon carbide alloy.

As regards the silicon carbide alloy, the silicon carbide alloy is usually selected from MAX phases, alloys of silicon carbide with elements, in particular metals, and alloys of silicon carbide with metal carbides and / or metal nitrides. Such silicon carbide alloys contain silicon carbide in varying and strongly fluctuating proportions. In particular, it can be provided that silicon carbide is the main component of the alloys. However, it is also possible that the silicon carbide alloy contains silicon carbide only in small amounts.

The silicon carbide alloy usually contains the silicon carbide, in particular the elements silicon and carbon, in amounts of 10 to 95% by weight, in particular 15 to 90% by weight, preferably 20 to 80% by weight, based on the silicon carbide alloy.

In the context of the present invention, a MAX phase is understood to mean, in particular, carbides and nitrides of the general formula M _{n + i} AX _n with n = 1 to 3 which crystallize in hexagonal layers. M stands for an early transition metal from the third to sixth group of the periodic table of the elements, while A stands for an element of the 13th to 16th group of the periodic table of the elements. After all, X is either carbon or nitrogen. As part of the However, only those MAX phases are of interest in the present invention, the empirical formula of which contains silicon carbide (SiC), ie silicon and carbon.

MAX phases have unusual combinations of chemical, physical, electrical and mechanical properties, as they show both metallic and ceramic behavior depending on the conditions. This includes, for example, high electrical and thermal conductivity, high resistance to thermal shock, very high levels of hardness and low coefficients of thermal expansion.

When the silicon carbide alloy is a MAX phase, it is preferred if the MAX phase is selected from TUSiC3 and T SiC.

If the silicon carbide-containing compound is an alloy of silicon carbide, in the event that the alloy is an alloy of silicon carbide with metals, it has proven useful if the alloy is selected from alloys of silicon carbide with metals from the group of Al, Ti, V, Cr, Mn, Co, Ni, Zn, Zr and their mixtures. If the alloy of silicon carbide is selected from alloys of silicon carbide with metal carbides and / or nitrides, it has proven useful if the alloys of silicon carbide with metal carbides and / or nitrides is selected from the group of boron carbides, in particular B4C, chromium carbides, in particular Cr2C3 , Titanium carbides, especially TiC, molybdenum carbides, especially M02C, niobearbides, especially NbC, tantalum carbides, especially TaC, vanadium carbides, especially VC, zirconium carbides, especially ZrC, tungsten carbides, especially WC, boron nitride, especially BN, and mixtures thereof.

If the SiC precursor material is used to produce a silicon carbide alloy, the SiC precursor material usually contains it

(A) silicon in amounts of 5 to 40% by weight, in particular 5 to 30% by weight, preferably 10 to 20% by weight, (B) the organic carbon compound in amounts of 10 to 60% by weight, in particular 15 to 50% by weight, preferably 20 to 50% by weight, and

(C) one or more precursors for alloy elements in amounts of 5 to 70% by weight, in particular 5 to 65% by weight, preferably 10 to 60% by weight, each based on the SiC precursor material.

It can also be provided that a doping reagent is added to the elemental silicon or the SiC precursor material. If a doping reagent is added to the elemental silicon or the SiC precursor material, it has proven to be advantageous if the doping reagent is used in amounts of 0.000001 to 15% by weight, in particular 0.000001 to 10% by weight, preferably 0.000005 to 5% by weight, preferably 0.00001 to 1% by weight, based on the mixture, is added.

As far as the chemical nature of the doping reagent is concerned, it can be selected from suitable doping elements. The doping reagent or the doping element is preferably selected from elements of the third and fifth main groups of the periodic table, which in particular are soluble in the dispersant.

It has now proven to be advantageous if the doping reagent is suitable for n- or p-doping, in particular is selected from the group of the elements nitrogen, phosphorus, boron, aluminum and indium, and mixtures thereof.

If doping with nitrogen is provided, the solution can contain nitric acid, ammonium chloride or melanin. If doping with phosphorus is provided, for example phosphoric acid or phosphates or phosphonic acids can be used. In addition, nitrogen doping is also possible by performing the method according to the invention in a nitrogen atmosphere.

If doping with boron is provided, for example boric acids, borates or boron salts such as boron trichloride are used.

If indium is doped, water-soluble indium salts, such as indium chloride, are usually used as the doping reagent. Thus, within the scope of the present invention, the silicon carbide produced, in particular the material containing silicon carbide, can thus be selected from silicon carbide, doped silicon carbide, non-stoichiometric silicon carbide, doped non-stoichiometric silicon carbide and silicon carbide alloys. With the A large number of different silicon carbide-containing materials, in particular different silicon carbide compounds, is thus accessible to the method according to the invention. Another object of the present invention - according to a second aspect of the present invention - is the SiC precursor material, containing elemental silicon and at least one organic carbon compound, obtainable by the process according to the invention. The SiC precursor material is preferably characterized in that the SiC precursor material is present as a precursor powder, in particular a microscale granular powder, preferably a nanoscale granular powder or as a precursor dispersion, in particular as a solid-in-liquid precursor dispersion. In addition, it is preferred if the precursor powder or the precursor dispersion contains or consists of homogeneous particles, in particular microparticles, preferably nanoparticles, preferably consists of them.

In a particularly preferred embodiment of the present invention, it has proven particularly useful if the precursor powder or the precursor dispersion is composed of homogeneous composite particles, in particular composite particles with a core-shell structure.

In this case it is particularly preferred if the composite particles, in particular those with a core-shell structure (core-shell structure), have a core made of elemental silicon and a shell made of at least one organic carbon compound, in particular a polymer or oligomer or a monomer.

For further details on this aspect of the invention, reference can be made to the above statements on the method according to the invention, which apply accordingly with regard to the SiC precursor material according to the invention.

Another object of the present invention - according to a third aspect of the present invention - is the use of an SiC precursor material, in particular an SiC precursor material with the aforementioned features, in high-energy processes, in particular in the context of selective synthetic crystallization processes. These high-energy processes are particularly suitable for applying silicon carbide-containing materials to a substrate surface, with generally gaseous, liquid or powdery precursor materials containing a silicon source and a carbon source being gasified and / or decomposed by the action of laser radiation. In particular, the use of the SiC precursor material according to the invention lends itself to the high-energy process for selective synthetic crystallization. Here, at least some of the decomposition products generated by the action of laser radiation are deposited in a location-selective manner on the substrate surface as silicon carbide, in particular silicon carbide-containing material.

The processes of selective synthetic crystallization allow the generation of high-resolution and detailed three-dimensional structures, i.e. H. the course of contours, such as corners or edges, is highly precise and, in particular, free of burrs.

In particular, the use of the SiC precursor material according to the invention in the high-energy process allows a very fast and inexpensive production of three-dimensional objects or coatings containing silicon carbide and, in particular, manages without the use of pressure in order to provide compact, non-porous or slightly porous materials and materials.

Starting from the SiC precursor material according to the invention, both layers of silicon carbide-containing materials can be applied to a substrate surface and three-dimensional objects can be built up from silicon carbide-containing materials. Likewise, it is also possible to join components by applying silicon carbide-containing materials or to add material defects in components.

Selective Synthetic Crystallization (SSC) is - as described at the beginning - an additive manufacturing process that can be carried out with various starting materials. In the context of selective synthetic crystallization, an object is manufactured in particular not from the melt but from the gas phase. In particular, precursor compounds are decomposed by the action of energy and converted into the gas phase, a rapid and locally sharply delimited phase Sublimation of the decomposition products to the desired silicon carbide compounds is observed.

For the details of the respective process management, reference can be made at this point to the relevant patent applications for the individual processes of selective synthetic crystallization, in particular the process based on laser deposition welding, as described in DE 10 2018 128434.9, as well as based on powder beds Method as described in DE 10 2017 110 362 A1, and on inkjet methods, as described in DE 10 2017 110 361 A1, in which a targeted energy input, in particular a location-selective energy input, is made from a SiC precursor material successively an object containing silicon carbide is produced.

In DE 102017 110362 A1, powdery SiC precursor materials are converted into silicon carbide-containing materials, in particular non-stoichiometric silicon-rich silicon carbides and silicon carbide alloys, by irradiation with a laser beam, for which purpose a device based on selective laser sintering (selective laser sintering) or . Selective Laser Melting (SLM) is used. The energy required to convert the precursor materials into the gas phase can be introduced into the powdery starting material through the laser radiation, whereby the precursor materials decompose into gaseous intermediate products, so that these then recombine directly to the desired products and are obtained in crystalline form. This method of selective synthetic crystallization is preferably carried out in several stages. For this purpose, in a first process step, the SiC precursor material is provided in the form of a layer or layer, and in a subsequent, second process step, it is converted into a silicon carbide-containing compound through the action of energy in certain areas. A layer of the three-dimensional object is thus produced, to which a further layer or layer of the SiC precursor material is applied in a subsequent third process step. The second and third process steps are repeated in total until the three-dimensional object is completed.

A special feature of the process is that it does not require subsequent sintering steps, ie within the scope of the present invention the SiC precursors are selected and, in particular, matched to the selective synthetic crystallization process, that each is produced directly from the gas phase homogeneous, compact, three-dimensional body is obtained, which does not have to be subjected to sintering.

If the SiC precursor material according to the invention is implemented in the context of selective synthetic crystallization based on laser deposition welding according to DE 10 2018 128434.9, it is advantageous if the powdery precursor material, in finely divided and directed form, in particular in the form of a particle beam, in Direction of a substrate is moved. Before or when it hits the substrate, the SiC precursor material is gasified and decomposed by the action of laser radiation, so that the gaseous decomposition products are moved in the direction of the substrate, in particular in the form of a particle beam.

A particle beam is to be understood here as a directed flow of particles or particles with a cross section that preferably remains constant and which preferably moves linearly.

It is advantageous that the SiC precursor material, in particular the powdery SiC precursor material, is gasified and decomposed by means of laser radiation, in particular in the immediate vicinity of the substrate surface, since this prevents secondary reactions and undesired agglomerations. In the context of the present invention, moreover, the substrate is heated only extremely slightly by the energy introduced, in particular by the laser beam, so that the silicon carbide-containing material can be applied with as little tension as possible.

Furthermore, it is an advantage that in particular crystalline silicon carbide absorbs laser energy significantly worse than the SiC precursor material. At the same time, silicon carbide conducts heat very well, so that the defined silicon carbide compounds are deposited in a strictly localized manner. Any unwanted constituents of the SiC precursor material and any byproducts formed form stable gases such as CO2, FI2O, etc. under the high temperatures of the laser action and can therefore be removed accordingly via the gas phase. Last but not least, the SiC precursor material can also be used in the context of selective synthetic crystallization on the basis of 3D printing techniques, in particular in the inkjet process, in combination with the targeted input of energy into the material Analogous to DE 10 2017 110 361 A1 can be implemented to objects containing silicon carbide.

For this purpose, a solution or dispersion of the SiC precursor, in particular an SiC precursor sol, is usually applied in the form of a layer to a substrate in a first process step and the layer of solution or dispersion containing SiC precursor is applied in a subsequent second process step converted into a silicon carbide-containing compound by selective energy action. These process steps are repeated until the desired silicon carbide-containing structure is obtained.

One advantage of this form of procedure for selective synthetic crystallization is to be seen in particular in the fact that, by varying the SiC precursor material with the same process, materials for semiconductor technology as well as mechanically and thermally extremely resistant materials are accessible.

Particularly good results are obtained in this connection when the process is an ink jet printing process, i.e. H. the solution and dispersion containing SiC precursor material is applied to the substrate by means of ink-jet printing. The use of inkjet printing processes allows, in particular, a high-resolution and locally sharply delimited application of the solution containing SiC precursor material, in particular the SiC precursor sol, while using little material at the same time, so that filigree structures are also accessible for semiconductor applications. In particular, it is furthermore preferred if so-called drop-on-demand processes or printers are used, with only the drops of liquid being generated which are actually actually applied to the substrate.

In addition, the SiC precursor materials can also be used in a large number of other processes for the production of silicon carbide-containing materials. Thus, the SiC precursor material according to the invention, in particular in the form of a precursor granulate, can be used for the production of silicon carbide-containing fibers and foams, as described in DE 10 2017 114 243 A1. In addition, the precursor material according to the invention, in particular in the form of a solution or dispersion, can be used to produce layers comprising silicon carbide, in particular nitrogen-free silicon carbide-containing layers, as disclosed in DE 10 2017 122 708 A1. The SiC according to the invention Precursor material, in particular in the form of solutions or dispersions, can also generally be used for the production of layers from silicon carbide, as disclosed in particular in DE 10 2017 112 756 A1. Overall, the SiC precursor material is characterized in that it enables the formation of specifically adjustable silicon carbide or materials containing silicon carbide. By using elemental silicon, in particular elemental silicon, which is obtained, for example, from silicon wafer production or solar cell production, the formation of disruptive, intercalating, by-products in the silicon carbide produced can be largely excluded. On the other hand, based on the composition of the SiC precursor material, it is rather ensured that only gaseous by-products are produced, which can easily be removed in the context of the method for producing silicon carbide. In this context, any doping, alloying or production of non-stoichiometric silicon carbide can therefore also be set in a targeted manner.

Thus, the use of the SiC precursor material according to the invention for the production of silicon carbide-containing materials or silicon carbide in a simple and, in particular, inexpensive manner allows reliable, reproducible and controllable access to silicon carbide-containing materials or silicon carbide of constant and high quality by means of methods that are carried out with little effort can.

For further details on this aspect of the invention, reference can be made to the above remarks on the further aspects of the invention, which apply accordingly with regard to the use according to the invention of the SiC precursor material.

Another object of the present invention - according to a fourth aspect of the present invention - is a method for producing silicon carbide-containing materials, in particular silicon carbide, from an SiC precursor material, in particular an SiC precursor material containing elemental silicon and at least one organic carbon compound, in particular at least one polymer or oligomer or monomer, the SiC precursor material being converted in high-energy processes at temperatures above 1,300 ° C, in particular above 1,600 ° C, preferably above 1,700 ° C. In the context of the process, it has proven to be advantageous if the reaction is carried out under an inert gas atmosphere, in particular under an argon atmosphere. Under inert conditions it is avoided, in particular and advantageously, that foreign elements are unwantedly incorporated into the silicon carbide produced.

In a preferred embodiment of the present invention, it has proven useful if the reaction takes place in a temperature range from 1,000 to 2,500.degree. C., in particular 1,300 to 2,200.degree. C., preferably 1,500 to 2,000.degree. C., preferably 1,700 to 1,900.degree .

In this temperature range it is ensured in particular and in an advantageous manner that an efficient conversion of the SiC precursor material takes place and, at the same time, a sublimation of the silicon carbide produced is efficiently prevented.

In the context of the method for producing silicon carbide, it has now also preferably proven itself if silicon carbide-containing materials, in particular silicon carbide, are obtained as a powder, in particular as a microscale powder, preferably as a nanoscale powder.

In this context, it is preferred that silicon carbide particles are obtained, in particular crystalline silicon carbide particles, preferably monocrystalline silicon carbide particles, preferably monocrystalline silicon carbide nanoparticles. Furthermore, it can preferably be provided that doped silicon carbide-containing material, in particular doped silicon carbide, is obtained, in particular as a powder, preferably as a nanoscale powder, preferably as a nanoscale, crystalline powder. Likewise, it can preferably be provided that a material containing silicon carbide alloy, in particular silicon carbide alloys, is obtained, in particular as a powder, preferably as a nanoscale powder, preferably as a nanoscale, crystalline powder. The silicon carbide produced with the method according to the invention is particularly distinguished by its high purity, so that it can ideally serve as a starting material for the production of silicon carbide wafers, for example. About that In addition, the ability to be freely doped and alloyed is a decisive advantage over known silicon carbides and their production methods. Last but not least, the silicon carbide produced from the SiC precursor material has an outstanding monodispersity and its grain size can be set variably.

For further details on this aspect of the invention, reference can be made to the above statements on the further aspects of the invention, which apply with regard to the method according to the invention for producing silicon carbide.

Another object of the present invention - according to a fifth aspect of the present invention - are silicon carbide-containing materials, in particular silicon carbide, obtainable from an SiC precursor material, in particular an SiC precursor material containing elemental silicon and at least one organic carbon compound, in particular at least one polymer or oligomer or monomer which can be obtained by the process according to the invention.

The silicon carbide-containing material, in particular silicon carbide, is preferably characterized in that the silicon carbide is present as a powder, in particular as a nanoscale powder, preferably as a single-crystalline nanoscale powder.

It is also preferred in this context if the silicon carbide is present in the form of particles, in particular nanoparticles, preferably monocrystalline nanoparticles.

For further details on this aspect of the invention, reference can be made to the above statements on the further aspects of the invention, which apply accordingly with regard to the silicon carbide according to the invention.

Claims

Patent claims:

1. A method for producing a SiC precursor material, characterized in that elemental silicon is mixed with at least one organic carbon compound.

2. The method according to claim 1, characterized in that the elemental silicon is used in the form of a powder, in particular in the form of a microscale powder, preferably in the form of a nanoscale powder.

3. The method according to claim 1 or 2, characterized in that elemental silicon with a degree of purity of at least 95%, in particular at least 98%, preferably at least 99%, preferably at least 99.5%, is used.

4. The method according to any one of the preceding claims, characterized in that the organic carbon compound is used in liquid form.

5. The method according to claim 4, characterized in that the organic carbon compound is a polymer or an oligomer or a monomer.

6. The method according to claim 5, characterized in that the polymer or oligomer is selected from the group of polyethers, polyethylene glycols, polysaccharides, polyketones, polyether ketones, polyesters, polycarbonates, polyhydroxyalkanoates and mixtures thereof, in particular polyethers, polysaccharides, polyesters, polycarbonates and mixtures thereof, preferably polysaccharides, and / or that the monomer is a monomer for producing the aforementioned polymers or oligomers, in particular is selected from the group of ethers, saccharides, esters, carbonates, carboxylic acids and mixtures thereof, preferably a saccharide.

7. The method according to any one of claims 4 to 6, characterized in that the organic carbon compound as a heterogeneous mixture, in particular as a heterogeneous mixture of monomers and monomer condensate, is preferably present as a heterogeneous mixture of monomer and dimeric, oligomeric or polymeric monomer condensate.

8. The method according to claim 6 or 7, characterized in that the saccharide is selected from the group of glucose and its stereoisomers, the

Fructose and its stereoisomers, xylose and its stereoisomers, the disaccharides of the aforementioned compounds, in particular glucose and / or fructose, preferably glucose and fructose, the oligosaccharides of the aforementioned compounds, in particular glucose and / or fructose, the polysaccharides of the aforementioned compounds, in particular glucose, or mixtures thereof.

9. The method according to any one of claims 6 to 8, characterized in that the saccharide is in the form of a liquid, in particular in the form of a syrup, preferably in the form of a highly concentrated syrup.

10. The method according to any one of the preceding claims, characterized in that the SiC precursor material is available as a precursor powder, in particular as a granular precursor powder, or as a precursor dispersion, in particular as a solid-in-liquid precursor dispersion.

11. The method according to claim 10, characterized in that the precursor powder or the precursor dispersion consists of homogeneous particles, in particular microparticles, preferably nanoparticles, or contains them, preferably consists thereof.

12. The method according to any one of claims 10 or 11, characterized in that precursor powder or the precursor dispersion consists of composite particles, in particular homogeneous composite particles, preferably composite particles with a core-shell structure (core-shell structure), or contains them, preferably from these consists.

13. SiC precursor material containing elemental silicon and at least one organic carbon compound, in particular a polymer or oligomer or monomer, obtainable by a process according to claims 1 to

12.

14. SiC precursor material according to claim 13, characterized in that the SiC precursor material is present as a precursor powder, in particular microscale granular precursor powder, preferably nanoscale granular precursor powder or as a precursor dispersion, in particular as a solid-in-liquid precursor dispersion.

15. SiC precursor material according to claim 14, characterized in that the precursor powder or the precursor dispersion contains or consists of homogeneous particles, in particular microparticles, preferably nanoparticles, preferably consists of them.

16. SiC precursor material according to one of claims 14 or 15, characterized in that the precursor powder or the precursor dispersion contains composite particles, in particular homogeneous composite particles, in particular composite particles with a core-shell structure (core-shell structure), or contains them consists, preferably consists of this.

17. Use of an SiC precursor material, in particular an SiC precursor material according to one of claims 13 to 16, in high-energy processes, in particular in the context of selective synthetic crystallization processes.

18. A method for producing silicon carbide-containing materials, in particular silicon carbide, from an SiC precursor material, in particular a SiC precursor material containing elemental silicon and at least one organic carbon compound, in particular a polymer or oligomer or monomer, characterized in that the SiC precursor material in high-energy Process at temperatures of over 1300 ° C, in particular over 1600 ° C, preferably over 1700 ° C, is implemented.

19. The method according to claim 18, characterized in that silicon carbide, in particular materials containing silicon carbide, is obtained as a powder, in particular as a nanoscale powder, preferably as a microscale powder.

20. Silicon carbide-containing material, in particular silicon carbide, obtainable from an SiC precursor material, in particular an SiC precursor material containing elemental silicon and at least one organic carbon compound, in particular a polymer or oligomer or monomer, according to claims 13 to 16.