DE10104536A1 - Novel borosilane compounds useful for the production of ceramic fibers, ceramic coatings, molded articles, film and/or ceramic microstructures by injection molding or lithographic processes - Google Patents

Abstract

New borosilane compounds (1) are claimed. New borosilane compounds of formula (1) are claimed. R xHal 3-xSi-NH-BR yHal 2-y(1) R : 1-20C hydrocarbon; Hal : Cl, Br or I; x : 1 or 2; y : 0 or 1. Independent claims are also included for the following: (i) A process for the production of a compound of formula (1) by reaction of a compound of formula (2) with a compound of formula (3) at -100 [deg]C to +25 [deg]C. (ii) A process for the production of a compound of formula (2) by reaction of a compound of formula (4) with a compound of formula (5). (iii) Borosilazane compounds of formula (6). (iv) A process for the production of the borosilazane compound of formula (6) by reaction of a compound of formula (1) with at least a 4-8 fold molar quantity of a compound of formula (7) at -80 to +300 [deg]C. (v) Oligo- or polyborosilazane compounds prepared by reaction of a compound of formula (1) and/or a compound of formula (6) with a compound of formula (7) or by polymerization of a compound of formula (1) or formula (4) so that it contains the structural groups C-Si-N-B, Si-N-B-C and/or C-Si-N-B-C. (vi) A process for the production of a siliconboroncarbonitride ceramic by heat treatment of a borosilazane compound of formula (6) or an oligo- or polyborosilazane compound in an inert or an amine and/or NH 3-containing atmosphere at 800-1700 [deg]C. (vii) The resulting silicon boroncarbonitride ceramic containing C-Si-N-B, Si-N-B-C and/or C-Si-N-B-C structural units and greater than 93 wt.% Si, N, B and C. (viii) A process for the production of a composite ceramic of SiC, Si 3N 4and BN by heating a siliconboroncarbonitride ceramic at above 1700 [deg]C. (ix) The resulting composite ceramic prepared by crystallization of a silicon boroncarbonitride ceramic containing molecularly dispersed SiC, Si 3N 4and BN. (x) Ceramic fibers prepared by melt spinning a polyborosilazane compound under an inert atmosphere, treating the spun green fibers, optionally in a separate process step with a reactive gas, preferably NH 3, ethylene diamine, trichlorosilane, dichlorosilane, borane-dimethylsulfide adduct, borane-triethylamine adduct, B 2H 6or with electromagnetic radiation or particle beam irradiation to render them unmeltable and heating the hardened green fibers at 800-1600 [deg]C, preferably 1200 [deg]C. R xHal 3-xSi-NH-SiR 3(2) BR yHal 3-y(3) R xSiHal 4-x(4) R 3Si-NH-SIR 3(5) (R'R''N) qR xHal 3-x-qSi-NH-BR yHal 2-y-z(NR'R'') z(6) R'R''NH (7) R', R'' : H or 1-20C hydrocarbon; q : 0-2; z : 0-2; q+z >= 1; x+q = 3; y+z = 2.

Description

The present invention relates to new alkylhalosilylaminoboranes, in particular alkylchlorosilylaminoboranes, which, by varying the number of reactive centers, make it possible to adjust the viscosity of polyborosilazane compounds, new borosilazane compounds, new oligo- or polyborosilazane compounds which have the structural feature R ¹ -Si-NH-BR ² , wherein R ¹ or R ² or both represent a hydrocarbon radical having 1 to 20 carbon atoms, in particular alkyl, phenyl or vinyl groups, silicon carbonitride ceramic powder, ceramic material based on SiC, SiN and BN, and processes for the respective production and use of polyborosilazanes and ceramic materials.

The production of multinary, non-oxide ceramics via molecular One-component precursor has become extremely important. It provides access to nitridic, carbidic and carbonitridic Substance systems that are beyond conventional solid-state reactions are accessible. The products are characterized by high purity, homogeneous element distribution and uniform particle size.

Materials made of silicon (Si), boron (B) and nitrogen (N) and possibly also consist of carbon (C) and none at the same time or contain only a small proportion of oxygen, show particular Properties in terms of thermal stability and Oxidation resistance. You can as bulk materials, in Composite materials, for coatings or as ceramic fibers find technical use. The boron-containing materials show in Generally an increased inhibition of crystallization, while  carbonaceous materials also a higher Have decomposition temperature as carbon-free ceramics. by virtue of the high mechanical resilience, the corrosion resistance high temperatures, thermal shock resistance and high Temperature resistance of such materials can be used, for example, as Reinforcement materials used for high temperature composites are and are used in the automotive industry and in the Aviation industry, for example in turbochargers, turbines from Jet engines, and for lining rocket nozzles and Combustion chambers.

The presentation of ceramics over inorganic is very promising Polymers. By networking molecular building blocks one obtains Polymers that can be converted to ceramics by pyrolysis. This already by Chantrell and Popper, Special Ceramics (Ed .: E. P. Popper), Academic Press, New York (1964), 87-103 committed path especially for carbide and nitride ceramics of the 3rd and 4th Main group new opportunities.

Winter, Verbeek and Mansmann (Bayer AG) (1975), US 3892583, developed the first spinnable inorganic polymers, the represented by aminolysis or ammonolysis of methylchlorosilanes were. They could be converted into Si / C / N fibers by pyrolysis. The The first fibers of commercial importance go back to Yajima, the Polycarbosilanes in carbon-rich SiC fibers (trade name NICALON) S. Yajima, J. Hayashi, M. Omori (1978), US 4100233.

The first homogeneous ceramic in the Si / B / N / C system with the approximate composition SiBN ₃ C was presented by Wagner, Jansen and Baldus, O. Wagner (1992), EP 502399. The fibers of this material, which is produced by aminolysis of the one-component precursor trichlorosilylamino dichloroborane (TADB) Cl ₃ Si (NH) -BCl ₂ , have an excellent property profile, HP Baldus, M. Jansen, Dr. Sporn, Science (1999) 285, p. 699. Ceramics from the precursor TSDE (trichlorosilyl dichloroborylethane, Cl ₃ Si- [CH-CH ₃ ] -BCl ₂ ) show further improved high-temperature properties M. Jansen, H. Jüngermann (Bayer AG ) (1997), WO 98/45302 A1.

The high temperature stability of the ceramics seems to improve with increasing carbon content. This shows e.g. B. the course of the decomposition temperatures (under inert gas conditions) of the ceramics Si ₃ B ₃ N ₇ , SiBN ₃ C (= Si ₃ B ₃ N ₇ .C _2.4 ) and SiBN _2.5 C ₂ (= Si ₃ B ₃ N ₇ .C ₆ ) which essentially differ only in the carbon content. The temperature stability increases from 1750 ° C over 1900 ° C to <2000 ° C.

The carbon and / or nitrogen content of the ceramics can be determined by the Choice of cross-linking reagents can be varied, M. Jansen, H. Jüngermann (1997), US 5866705. In addition to methylamine or Ammonia with other amines such as. B. guanidine to polymers be implemented.

In the ceramics mentioned, silicon and boron are exclusively from Nitrogen coordinates. Realization of new structural features like Si-C- or B-C bonds in ceramics leads to improved mechanical and thermal strength of a ceramic.

The adjustment of the viscosity of a polymer for a corresponding one Processing process can e.g. B. by thermal pretreatment happen. However, the known polymers in the Si / B / N / C system have the Disadvantage that the thermal crosslinking in the liquid d. H. melted Condition increases continuously and so does the viscosity during the Processing does not remain constant. This causes significant problems such as B. clogging of the nozzles during fiber drawing. For one if possible  High warpage during fiber drawing is advantageous for linearly cross-linked molecules. The one-component precursors mentioned have too many reactive centers, that lead to multidimensional networking. However, it would be advantageous a polymer consisting mainly of chains.

An object of this invention is therefore to provide novel, in high yields of representable organometallic precursor compounds and a method for producing nitride ceramics from these Precursor compounds consisting of Si, N, B and C and which overcome the disadvantages mentioned. The monomeric precursors are said to pass through setting the number of reactive centers d. H. of halogen atoms a way to adjust the viscosity during implementation Offer polyborosilazanes. In particular, the constancy of the viscosity in liquid form is said to be improved. This procedure is intended the presentation of ceramics with high carbon content enable. In ceramics, silicon is said to be partly carbon be coordinated.

This object is achieved according to the invention by amorphous ceramics or nanocomposites, their precursor compounds, the respective Process for their preparation and the use of polyborosilazanes and the ceramic materials as set out in the claims are disclosed.

In a first aspect, the invention relates to a compound of the general formula (I)

R _x Hal _3-x Si-NH-BR _y Hal _2-y (I)

where R each independently represents a hydrocarbon radical having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms,
Hal is independently Cl, Br or I,
x = 1 or x = 2 and
y = 0 or y = 1.

The compounds according to the invention are Alkylhalosilylaminoborane, which at least one to the Silicon atom-bonded hydrocarbon residue. Such Compounds have the structural feature C-Si-N-B, C-Si-N-B-C or / and Si-N-B-C and therefore already contain carbon in the basic structure. With such connections can be made of ceramics based on the increased carbon content and the realization of new ones Structural features such as Si-C or B-C bonds an improved have mechanical and thermal resilience. The substitution of Halogen residues in the alkylhalosilylaminoboranes according to the invention through hydrocarbon residues, both on Si and on B, leads in addition to the advantageous introduction of carbon to a targeted reduction of the number of reactive halogen atoms. This can the viscosity of those formed from the compounds of the invention Oligomers or polymers are varied and / or adjusted. Especially compounds which have three hydrocarbon radicals (x + y = 3) are advantageous which have two halogen atoms capable of crosslinking included, which limits multidimensional networking.

In the formula I, the radical R each independently represents a hydrocarbon radical having 1 to 20 carbon atoms, preferably having 1 to 10 carbon atoms. A hydrocarbon residue is a residue that is formed from the elements carbon and hydrogen. According to the invention, the hydrocarbon radical can be branched or unbranched, saturated or unsaturated. The hydrocarbon radical can also contain aromatic groups, which in turn can be substituted with hydrocarbon radicals. Examples of preferred hydrocarbon radicals are e.g. B. unbranched saturated hydrocarbon radicals, such as C ₁ to C ₂₀ alkyl, in particular methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl and n decyl. The radicals R can also be branched saturated hydrocarbons, in particular branched C ₁ to C ₂₀ alkyls, such as i-propyl, i-butyl, t-butyl, and further branched alkyl radicals. In a further preferred embodiment, the radical R comprises one or more olefinically unsaturated groups. Examples of such radicals are vinyl, allyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, butadienyl, pentadienyl, hexadienyl, heptadienyl, octadienyl, nonadeinyl and decadienyl. The radical R can also contain an alkyne group, ie a C∼C bond. In a further preferred embodiment, at least one radical R and preferably all radicals R contain an aromatic group, in particular an aromatic radical having 5 or 6 carbon atoms, such as a phenyl group or a phenyl group substituted by a hydrocarbon, such as methylphenyl, dimethylphenyl, trimethylphenyl , Ethylphenyl, or propylphenyl.

Particularly preferably at least one radical R and in particular all radicals R comprise a C ₁ to C ₂₀ alkyl group, a phenyl group, a vinyl group or a hydrocarbon radical with 1 to 3 C atoms, in particular methyl, ethyl or propyl and most preferably methyl.

The rest Hal stands for a halogen atom and means in particular Cl, Br or I, it being preferred that at least one radical is Hal and preferred all radicals mean Hal Cl. Such connections are Alkylchlorsilylaminochlorborane.

Particularly preferred embodiments of the invention are compounds of the formula RHal ₂ Si-NH-BHal ₂ , where the radicals R and Hal have the meanings given above and in particular the meanings given above as preferred. These compounds contain the structural feature C-Si-NB and they have four halogen atoms which are reactive towards oligomerization or polymerization. A particularly preferred example of such a compound is (methyldichlorosilylamino) dichloroborane (MADB). Compounds of the formula R ₂ HalSi-NH-BHal ₂ are also preferred. Such compounds contain two hydrocarbon residues on the Si atom, which can further increase the carbon content of a ceramic produced from such compounds. Furthermore, such compounds have only three halogen atoms which are reactive towards oligomerization or polymerization, as a result of which the viscosity of oligomers or polymers formed therefrom can be varied further. A particularly preferred example of such compounds with two alkyl radicals and three halogen radicals is (dimethylchlorosilylamino) dichloroborane (DADB). In general, compounds of the formula (I) with the structural element BHal _{2 are} very preferred.

Other preferred compounds include (vinyldichlorosilylamino) dichloroborane, (divinylchlorosilylamino) dichloroborane, (Phenyldichlorosilylamino) -dichlorborane, (diphenylchlorosilylamino) - dichloroborane, (ethyldichlorosilylamino) dichloroborane and (Diethylchlorsilylamino) -dichlorboran.

In addition, the invention comprises compounds with the structural feature -BRHal, in which the boron atom is bonded to a hydrocarbon radical and to a halogen. Such compounds preferably have the formula RHal ₂ Si-NH-BRHal or R ₂ HalSi-NH-BRHal. By replacing a halogen on boron with a hydrocarbon residue, precursors with a further increased carbon content and a further reduced functionality with regard to crosslinking can be formed. Compounds RHal ₂ Si-NH-BRHal have only three and compounds R ₂ HalSi-NH-BRHal even only two halogen atoms reactive to oligomerization or polymerization. Particularly preferred examples of these compounds are (methyldichlorosilylamino) -methylchloroborane, (dimethylchlorosilylamino) -methylchloroborane, (phenyldichlorosilylamino) -phenylchloroborane, (diphenylchlorosilylamino) -phenylchlorborane, (vinyldichlorosilylamino-chloro-vinylchloride).

The compounds of the general formula (I) according to the invention can be obtained by reacting a compound of the formula (II)

R _x Hal _3-x Si-NH-SiR ₃ (II)

with a compound of formula (III)

BR _y Hal _3-y (III)

at a temperature between -100 ° C and + 25 ° C.

Suitable and preferred meanings for R, Hal, x and y are as above specified. The reaction can be carried out in an organic solvent such as about n-hexane or toluene, for example, the Compound of formula (II) one in an organic solvent dissolved compound of formula (III) is added dropwise. Is preferred but worked without solvents. The reaction temperatures are preferably at least -90 ° C and very particularly preferably at least -80 ° C and preferably at most 0 ° C, particularly preferably at most -50 ° C. Particularly advantageous results are obtained from a Receive reaction at a temperature of about -78 ° C.

The compounds of the formula (I) according to the invention can also be prepared by reacting a compound of the formula (II)

R _x Hal _3-x Si-NH-SiR ₃ (II),

where R each independently represents a hydrocarbon radical having 1 to 20 carbon atoms,
Hal each independently means Cl, Br or I and
x is 1 or 2,
with a compound of formula (III)

BR _y Hal _3-y (III),

wherein R and Hal have the meanings given above and
y is 0 or 1,
in a molar ratio of 1: 1 to 1:10. The compound of the formula (II) and the compound of the formula (III) are preferably reacted in a molar ratio between 1: 1 and 1: 5. Particularly advantageous results are obtained in a process in which both the temperature limits specified here and the molar ratio are observed.

The starting compound of the formula (II) R _x Hal _3-x Si-NH-SiR ₃ used in the preparation of the compound of the formula (I) according to the invention can be prepared by using R _x SiHal _4-x and R ₃ Si-NH-SiR _{3 is} implemented. In a preferred embodiment, a compound of the formula (IIa) R ₂ HalSi-NH-SiR _{3 is} prepared as a starting material compound by using R ₂ SiHal ₂ and R ₃ Si-NH-SiR ₃ in a molar ratio of 1: 1 to 1.5: 1, preferably from 1.1: 1 to 1.4: 1 and particularly preferably from 1.2: 1 to 1.3: 1. Particularly good results are obtained if the two compounds R ₂ SiHal ₂ and R ₃ Si-NH-SiR _{3 are used} in a molar ratio of about 5: 4.

The starting compound of the formula (IIa) R ₂ HalSi-NH-SiR ₃ and in particular the silane with R = CH ₃ can also be prepared by reacting R ₂ SiHal ₂ and R ₃ Si-NH-SiR ₃ at a reaction temperature from 40 to 60 ° C. Particularly high yields of <70%, preferably <80%, of the starting material compound can be obtained if the reaction is carried out taking into account both the stated reaction temperature and the stated molar ratio.

The preparation of the educt compounds and the compounds of General formula (I) is based on the preparation of two particularly preferred compounds MADB and DADB again explained in detail.

Amazingly, the implementation of (1,1-dichlorotetra methyl) disilazane or (chloropentamethyl) disilazane with boron trichloride Presentation of the two new compounds (methyldichlorosilyl amino) dichloroborane (MADB) and (dimethylchlorosilylamino) dichloroborane (DADB). These connections both contain the structural feature C-Si-N-B. MADB has four reactive to oligo- or polymerisation Halogen atoms, DADB only three. Thus, by choosing one of the Molecules or by mixing both molecules in any one Ratio the viscosity of the oligomers or polymers to be displayed varies become. Both molecules are the subject of this invention.

The educt (1,1-dichlorotetramethyl) disilazane can be prepared with a yield of over 80% from hexamethyldisilazane and Methyltrichlorosilane by stirring at room temperature. The production of the Educts (chloropentamethyl) disilazane can be achieved by the reaction of Hexamethyldisilazane and dimethyldichlorosilane.

According to the invention, (chloropentamethyl) disilazane can be produced in a yield of over 70% if the ratio of the reactants Me ₂ SiCl ₂ and hexamethyldisilazane is 5: 4 and the reaction temperature is 40 to 60 ° C.

According to the invention, the compounds MADB and DADB are formed in Aus save 80% and 70% of theory by dropping the educts  Boron trichloride, which can be dissolved in an organic solvent (e.g. n-hexane, toluene). The molar ratios of boron trichloride to the starting materials are between 5: 1 and 1: 1. The reaction temperatures can be between -100 ° C and room temperature vary, the preferred value is -78 ° C.

Monomeric, oligomeric or polymeric borosilazane compounds can be prepared from the compounds of general formula (I) according to the invention by reaction with primary or secondary amines. In such borosilazane compounds, the halogen atoms of the compound of the formula (I) are substituted in whole or in part by amino groups. The invention therefore further relates to borosilazane compounds of the general formula (IV):

(R'R "N) _q R _x Hal _3-xq Si-NH-BR _y Hal _2-yz (NR'R") _z , (IV)

wherein R 'and R "each independently represent hydrogen or a hydrocarbon radical having 1 to 20 carbon atoms,
R each independently represents a hydrocarbon radical having 1 to 20 carbon atoms,
Hal is independently Cl, Br or I,
q = 0.1 or 2,
x = 1 or 2,
y = 0 or 1 and
z = 0.1 or 2,
with the proviso that q + z ≧ 1, x + q ≧ 3 and y + z ≦ 2.

The borosilazane compounds of the formula (IV) according to the invention contain at least one hydrocarbon radical which is bonded to the Si atom, so that they have the structural feature C-Si-NB. Compounds in which the halogen atoms are partially substituted by the amino groups R'R "N thus contain hydrocarbon radicals, halogen and amine radicals as substituents on the Si or B. However, preference is given to borosilazane compounds of the formula (IV) in which the halogen atoms are completely substituted by amino groups Such compounds have the formula (IVa) (R'R "N) _q R _x Si-NH-BR _y (NR'R") _z , where q + x = 3 and y + z = 2.

If one or more halogen atoms of the borosilazane compound it is preferred that Hal occur in at least one occurrence and preferably represents Cl at each occurrence.

Borosilazane compounds having the formula are also preferred

(R'R "N) R Hal Si-NH-B Hal ₂ ,

(R'R "N) R ₂ Si-NH-B Hal ₂ ,

(R'R "N) ₂ R Si-NH-B Hal ₂ ,

R ₂ Hal Si-NH-B Hal (NR'R "),

R ₂ Hal Si-NH-B R (NR'R "),

R ₂ Hal Si-NH-B (NR'R ") ₂ ,

(R'R "N) R ₂ Si-NH-B Hal (NR'R"),

(R'R "N) R Hal Si-NH-B Hal (NR'R"),

(R'R "N) R Hal Si-NH-B R (NR'R"),

(R'R "N) R Hal Si-NH-B (NR'R") ₂ ,

(R'R "N) ₂ R Si-NH-B Hal (NR'R"),

(R'R "N) R Hal Si-NH-B R Hal,

(R'R "N) R ₂ Si-NH-B R Hal or

(R'R "N) ₂ R Si-NH-B R Hal.

Borosilazane compounds in which all halogen atoms have been replaced by amino groups, which therefore only have hydrocarbon radicals or amino group radicals, are also particularly preferred. Such connections have the formulas

(R'R "N) R ₂ Si-NH-B (NR'R") ₂ ,

(R'R "N) R ₂ Si-NH-B R (NR'R"),

(R'R "N) ₂ R Si-NH-B R (NR'R") or

(R'R "N) ₂ R Si-NH-B (NR'R") ₂ .

In the above formulas, the radical R has that at every occurrence indicated above for the compound (I) and in particular as there preferably indicated meanings. It is particularly preferred R is a hydrocarbon radical with 1 to 3 carbon atoms, in particular a methyl, ethyl or propyl radical or a phenyl radical or a vinyl residue.

The radicals R 'and R "each independently represent hydrogen or a hydrocarbon radical having 1 to 20 C atoms, preferably having 1 to 10 C atoms. Compounds in which at least one of the radicals R' and R" are a hydrocarbon radical are preferred represents with 1 to 20 carbon atoms. R 'and R "are particularly preferably selected from C ₁ to C ₂₀ alkyl groups, in particular C ₁ to C ₃ alkyl groups, such as methyl, ethyl, propyl, and phenyl or vinyl groups.

Compounds in which both R and R 'and R "are methyl each time they occur are particularly preferred. The borosilazane compounds according to the invention can be prepared by adding a compound of the formula (I) with at least four to eight times (depending on the molecule) Number of halogen atoms times two), preferably at least ten times the molar amount of a compound of the formula (V) R'R "NH at a temperature of -80 ° C to + 300 ° C. In this way, from the compounds of the formula (I), which can be used individually or in any mixing ratio, by reaction with primary and / or secondary amines, monomeric or oligomeric or polymeric compounds of the preferred formulas

(NR'R ") ₂ R Si-NH-B (NR'R") ₂

(NR'R ") R Si-NH-B (NR'R") ₂ or

[- (NR'R ") R Si-NH-B (NR'R") -] _a , where a indicates the degree of polymerization,

produce. Other monomeric borosilazanes and polyborosilazanes are also possible, in particular those which have crosslinked structures. Using the compounds MADB and TADB described by way of example above, compounds of the formula (NRR ') ₂ (CH ₃ ) Si-NH-B / NRR') ₂ or (NRR ') (CH ₃ ) ₂ Si-NH-B ( NRR ') ₂ or [(NRR') (CH ₃ ) Si-NH-B (NRR ')] _a can be obtained. The monomeric or oligomeric units are characterized in that the first coordination sphere of each silicon atom consists of carbon and nitrogen atoms. The borosilazane compounds of the formula (IV) according to the invention are preferably prepared by adding a compound of the formula (I) with at least four to eight times (depending on the molecule) the number of halogen atoms times two, preferably at least ten times the molar amount, more preferably at least 20 times the molar amount of a compound of the formula (V)

R'R "NH (V)

at a temperature of -80 ° C to + 300 ° C.

The monomeric or oligomeric units can be by Heat treatment and / or by crosslinking with ammonia or an amine to be converted into polymers.

The temperature treatment can preferably be carried out at temperatures of -80 ° C to + 500 ° C, more preferably to + 300 ° C and most preferably to + 200 ° C.  

The invention therefore further relates to an oligo or Polyborosilazane compound, which by reacting a compound of Formula (I) and / and a compound of formula (IV) with a compound of formula (V) or by polymerizing a compound of formula (I) or the formula (IV) is available. Such oligo- or polyborosilazane Compounds have the structural feature C-Si-N-B or / and Si-N-B-C. The first coordination sphere of the silicon atoms preferably consists of Oligo- or polyborosilazene compounds according to the invention both from Carbon as well as from nitrogen, the silicon atoms and / or the Boron atoms represent a radical R and the nitrogen atoms represent a radical R 'or R " wear.

The viscosity of the oligosilazane or polyborosilazane according to the invention connections can be used by the choice of the radicals R in the Compound of formula (I), by the choice of the radical R 'and R "the Amines used and, if appropriate, by the type of Temperature treatment vary.

According to the invention, a variation of the viscosity is the same Heat treatment and use of the same amines e.g. B. by the Choice of the monomer MADB or DADB or a mixture of these Molecules possible. Also the methyl group (s) of this One-component precursors can e.g. B. by alkyl, phenyl or Vinyl groups are replaced in whole or in part, so a higher one To deliver carbon content of the polymers.

The reaction of the monomers with the amines mentioned can be carried out either in open as well as in closed systems. The Reaction temperatures are between -78 ° C and + 500 ° C, the Response time between 5 minutes and 20 days.  

Amines suitable for the reaction include, for example, methylamine, Ethylamine, dimethylamine, aniline or ammonia. The reaction can be both in the pure components as well as in an aprotic solvent, such as hexane, toluene, THF or methylene chloride. The reaction temperature is preferably at least -78 ° C, more preferably at least -50 ° C and most preferably at least -30 ° C and up to preferably at most 100 ° C, more preferably up to at most 5 ° C.

Depending on the radicals R, R 'and R "and on the degree of polymerization, the consistency of the polyborosilazanes according to the invention ranges from slightly viscous to resinous or wax-like to a solid amorphous or crystalline state. The thermal crosslinking takes place by splitting off an amine radical by linking new Si-N or BN bonds. The crosslinking by means of ammonia takes place by substitution of an NR'R "group by an NH ₂ group, which then crosslinks further.

The degree of crosslinking of the polyborosilizanes can thus be determined by the type of Polymerization, for example by polycondensation Heat treatment or crosslinking with ammonia or an amine set specifically. It was found that the Processing properties of the polyborosilazanes according to the invention Have fibers further improved by using suitable reaction parameters of polycondensation. This particularly preferably includes Process according to the invention for producing an oligo or Polyborosilazane compound therefore at least one process section, in which a polycondensation at temperatures of ≦ 200 ° C or / and is carried out at a reduced pressure. Under these "Linearized" oligomers or Prepolymers with particularly favorable ones for the melt spinning process rheological properties. The curability of the green fibers with Reactive gases are not affected. In addition, the homogeneity of the  Polymers in terms of element distribution in these preferred Reaction conditions further improved.

Polyborosilazanes, which are to be processed into fibers, can from chlorinated precursors, such as TADB, by the precursors in an inert solvent such as hexane with a Amine, such as methylamine. Besides insoluble This creates methylammonium chloride, which can be filtered off a soluble borosilazane oligomer mixture. After distilling off the The still liquid material is then thermally dissolved Leakage of methylamine polycondensed until an at Room temperature solid product suitable for the melt spinning process is obtained. For the borosilazane made from TADB Oligomer mixtures are used for thermal polycondensation conveniently temperatures of about 250 ° C used. In the case of out MADB or DADB are produced borosilazane oligomeric mixtures due to the lower number of networking points per Monomer unit often higher temperatures of up to 500 ° C advantageous.

However, there are connections with the structural unit ∼Si-N (R) -B = thermally sensitive and can easily form decompose from monosilane and borazine derivatives. Such Decomposition reaction with the leakage of mono- and oligosilazanes can also during the polycondensation of borosilazane-oligomer mixtures take place at elevated temperatures. Often this does Decomposition reaction the occurrence of inhomogeneities in the Element distribution. The advantage of a one-component precursor, namely in particular a homogeneous distribution of elements in the ceramic End product, can be separated into a two-component system are lost, causing the high temperature properties of the material can deteriorate. For this reason, have  Process temperatures for the polycondensation of an oligomer Mixtures of ≦ 200 ° C, preferably ≦ 180 ° C, more preferably ≦ 150 ° C and at least 50 ° C, more preferably ≧ 100 ° C as advantageous proved. In the event that this temperature at the selected Starting materials are not sufficient to make a solid at room temperature To receive product, which in particular when used later the reaction is required in the melt spinning process advantageously carried out under vacuum. The pressure is preferably ≦ 90 kPa, more preferably ≦ 10 kPa, more preferably ≦ 1 kPa.

In this preferred procedure, a polyborosilazane is obtained with a very homogeneous distribution of elements. In addition, it has a good processability to green fibers and can be chemically hardened and be ceramized. Another benefit of running the process under Vacuum consists in the fact that mono- or Oligosilazanes can be distilled off in vacuo and thus that Do not contaminate the product.

The desired ones can be obtained from the polyborosilazanes according to the invention Silicon borocarbonitride ceramics are produced. Another The invention therefore relates to a method for producing a Silicon carbobornitride ceramic, which is characterized in that a monomeric, oligomeric or polymeric borosilazane compound, such as described herein in an inert or amine containing, and, if carbon-free ceramics are desired, one containing ammonia Atmosphere at temperatures between 800 ° C and 2000 ° C, preferred between 1000 ° C and 1800 ° C, and most preferably at 1350 ° C tempered up to 1750 ° C. By aminolysis or ammonolysis reaction and Subsequent pyrolysis the borosilazanes into a silicon carbo transferred boron nitride ceramic powder. C-Si-N-B- Structural units in front and the elements Si, N, B and C are more than 93 % By mass, more preferably more than 97% by mass. The  Silicon carbobornitride ceramic according to the invention is particularly distinguished due to their low oxygen content of preferably <7% by mass, more preferably <1 mass% and most <0.5 mass%. With the inventive method for producing a Silicon carbobornitridkeramik it is possible to manufacture ceramics that are practically free of oxygen. For the implementation of the Borosilazane compounds with ammonia can be found in all literature Use aminolysis or ammonolysis processes of tetrachlorosilane, for example, the implementation with solid or liquid ammonia low temperatures (US-A-4196178), the reaction with gaseous Ammonia in an organic solvent (US-A-3959446) or the Reaction with ammonia in a high temperature reaction Elimination of hydrogen chloride (US-A-4145224).

The inert atmosphere can be selected from an inert gas atmosphere, for example an argon or helium atmosphere, one Nitrogen atmosphere or an atmosphere from another inert gas, which under the reaction conditions between 800 ° C and 2000 ° C. does not react with the reactants.

The ceramic yields in the pyrolysis are generally between 65% and 80%. The pyrolysis product is a ceramic material which consists of more than 93% by mass, preferably more than 97% by mass, of the elements Si, N, B and C and the structural units C-Si-NB, Si-NBC or Si -NB contains. The silicon boron carbonitride ceramic according to the invention can be amorphous or at least partially crystalline in the pyrolysis. It is preferably an amorphous silicon borcarbonitride. The silicon borocarbonitride ceramic according to the invention is particularly characterized by a high temperature resistance and an inertness towards oxygen. The elements contained within the ceramic are almost completely homogeneously distributed. The amorphous material can be crystallized to form a composite ceramic made of SiC, Si ₃ N ₄ and BN by aging at a temperature <1700 ° C. In such a crystalline composite ceramic, SiC, Si ₃ N ₄ and BN crystallites, preferably on a nanometer scale, are essentially completely homogeneously distributed, that is to say are present in a molecularly disperse distribution. The ceramics according to the invention are distinguished in particular by their high temperature resistance. In addition to the amorphous ceramics, crystalline ceramics and processes for their production, the present invention also relates to the use of the monomeric, oligomeric or polymeric borosilazane compounds and the amorphous and at least partially crystalline ceramic materials for the production of ceramic fibers, ceramic coatings, ceramic moldings, ceramic films or / and ceramic microstructures.

The polyborosilazanes can be directly or dissolved in organic solvents can be processed into moldings, fibers, foils or coatings. According to the invention, the viscosity of the polymers can be selected by choosing used compounds of formula (I), such as. B. the ratio between MADB or DADB can be adapted to requirements.

The shaped polyborosilazanes can undergo pyrolysis and / or physical or chemical pretreatment, e.g. B. a hardening or Crosslinking, to be subjected to the infusible polymer do.

A suitable treatment for the production of infusible Polyborosilazanes are described, for example, in DE 195 30 390 A1, where infusible compounds there by reaction with borane Amine adducts can be obtained.

The microstructures can, for example, by injection molding or lithographic processes are generated. The are particularly preferred  Ceramics made in the form of fibers from which, for example Fabrics or braids are made that are used as fillers to increase the strength or toughness can be used for other ceramics can.

Furthermore, the borosilazane compounds according to the invention can also be used in chemical vapor deposition (CVD) or physical Gas phase separation (PVD) can be used. Through the coating of substrates by means of CVD or PVD can ceramic coatings getting produced. The gas phase separation can be as in the state described in the art, can be performed (see e.g. DE 196 35 848 C1).

The invention is illustrated below with the aid of a few examples that there is a limitation:

example 1 The synthesis of (1,1-dichlorotetramethyl) disilazane

Me ₃

Si (NH) SiMe ₃

+ MeSiCl ₃

→ MeCl ₂

Si (NH) SiMe ₃

+ Me ₃

SiCl

178.8 g (1.20 mol, 141.2 ml) of MeSiCl ₃ with 64.4 g of hexamethyldisilazane (0.40 mol, 50.0 ml) are stirred for two days at room temperature in a 250 ml three-necked flask with pressure relief valve and magnetic stirrer.

The excess methylchlorosilane and the trimethylchlorosilane formed become slow at room temperature with continuously falling pressure distilled off. The purification is carried out by fractional distillation a Vigreux column.  

The boiling point is 39 ° C at p = 13 mbar, the yield 85% of the Theory.

Mass spectroscopy on (1,1-dichlorotetramethyl) disilazane:
m / z = 202 (M ⁺ ), 187 (M ⁺ - CH ₃ ), 170 (M ⁺ - 2CH ₃ ), 150 (M ⁺ - Cl - CH ₃ ).

NMR spectroscopy on (1,1-dichlorotetramethyl) disilazane:
¹ H NMR (C ₆ D ₆ ): δ = 0.03 ppm (s, 9H); 0.47 ppm (s, 3H).

Example 2 The synthesis of (chloropentamethyl) disilazane

Me ₃

Si (NH) SiMe ₃

+ Me ₂

SiCl ₂

→ Me ₂

ClSi (NH) SiMe ₃

+ Me ₃

SiCl

51.6 g of Me ₂ SiCl ₂ (0.50 mol, 50.0 ml) with 64.4 g (0.40 mol, 66.8 ml) of hexamethyldisilazane are stirred for two days at 50 ° C. in a 250 ml three-necked flask with pressure relief valve and magnetic stirrer. The excess methylchlorosilane and the trimethylchlorosilane formed are slowly distilled off at room temperature with continuously decreasing pressure (membrane pump). The purification is carried out by distillation using a Vigreux column. The boiling point is 34 ° C at p = 10 mbar, the yield: 70% of theory.
MS (EI): m / z = 182 (M ⁺ ), 166 (M ⁺ - CH ₃ ), 150 (M ⁺ - 2CH ₃ ), 146 (M ⁺ - Cl).
¹ H NMR (C ₆ D ₆ ): δ = 0.07 (s, 9H); 0.29 (s, 6H).

Example 3 Synthesis of (methyldichlorosilylamino) dichloroborane (MADB)

MeCl ₂

Si (NH) SiMe ₃

+ BCl ₃

→ MeCl ₂

Si (NH) BCl ₂

+ Me ₃

SiCl

23.4 g (0.20 mol, 16.36 ml) of BCl ₃ are placed in a 250 ml three-necked flask with dropping funnel, pressure relief valve and magnetic stirrer at -78 ° C. 21.2 g (0.10 mol) of methylchlorodisilazane are added dropwise with stirring over the course of 1 h. Allow to warm up overnight while stirring further.

Excess BCl ₃ and the trimethylchlorosilane formed are slowly distilled off at room temperature with continuously decreasing pressure (membrane pump). The product is a colorless oil. The crude product is cleaned by distillation. The boiling point is 38 ° C at p = 13 mbar, the yield about 80% of theory.
MS (EI): m / z = 196 (M ⁺ - CH ₃ ), 174 (M ⁺ - HCl), 158 (M ⁺ - HCl - CH ₃ ), 138 (M ⁺ - 2HCl).
¹ H NMR (C ₆ D ₆ ): 0.47 (monomer), 0.49 (dimer).

Example 4 Synthesis of (dimethylchlorosilylamino) dichloroborane (DADB)

Me ₂

ClSi (NH) SiMe ₃

+ BCl ₃

→ Me ₂

ClSi (NH) BCl ₂

+ Me ₃

SiCl

29.8 ml (0.36 mol) of BCl ₃ are placed in a 250 ml three-necked flask with dropping funnel, pressure relief valve and magnetic stirrer at -78 ° C. 32.9 g (0.18 mol) of methylchlorodisilazane are added dropwise with stirring over the course of 1 h. Allow to warm up overnight while stirring further. Excess BCl ₃ and the trimethylchlorosilane formed are slowly distilled off at room temperature with continuously decreasing pressure (membrane pump). The product is a colorless oil. The crude product is cleaned by distillation. The boiling point is 28 ° C at p = 0.1 mbar, the yield about 70% of theory.
MS (EI): m / z = 174 (M ⁺ - CH ₃ ), 154 (M ⁺ - Cl), 138 (M ⁺ - Cl - CH ₃ ).
¹ H NMR (C ₆ D ₆ ): 0.16 (monomer), 0.32 (dimer).

Example 5 Ammonolysis by MADB

80 ml of ammonia dried over sodium are placed in a 500 ml three-necked flask with dropping funnel, pressure relief valve and magnetic stirrer at -78 ° C. 15.6 g of MADB dissolved in 100 ml of pentane are added dropwise with stirring over the course of 2 hours. A white precipitate forms at the dropping point, which quickly dissolves in the large excess of ammonia. The reaction mixture is allowed to warm to room temperature overnight with stirring. Colorless hydrochlorides precipitate out. The polymer formed is insoluble in organic solvents. The by-product ammonium chloride is extracted with liquid ammonia. After the extraction, the polymer remains as a colorless powder.
IR (KBr): 3435: v (NH), 2964: v _as (CH), 2903: v _s (CH), 1406: v (BN), 1265: δ _s (CH ₃ ), 994: v (Si N), 779: v (Si-C).

Example 6 Ammonolysis by DADB

80 ml of ammonia dried over sodium are placed in a 500 ml three-necked flask with dropping funnel, pressure relief valve and magnetic stirrer at -78 ° C. 12.6 g of DADB dissolved in 100 ml of pentane are added dropwise with stirring over the course of 2 hours. A white precipitate forms at the dropping point, which quickly dissolves in the large excess of ammonia. The reaction mixture is allowed to warm to room temperature overnight with stirring. Colorless hydrochlorides precipitate out. The polymer soluble in pentane is separated from the precipitated ammonium chloride by filtration. The precipitate is washed three times with 20 ml of pentane. The pentane is distilled off from the filtrate at room temperature in vacuo (10 mbar). A highly viscous, colorless liquid remains.
IR (KBr): 3451: v (NH), 2960: v _as (CH), 2900: v _s (CH), 1382: v (BN), 1254: δ _s (CH ₃ ), 939: v (Si N), 783: (Si-C).

Example 7 Aminolysis by MADB

130 ml of methylamine dried over molecular sieve (4 Å) are placed in a 500 ml three-necked flask with dropping funnel, pressure relief valve and magnetic stirrer at -78 ° C. 16.9 g of MADB dissolved in 120 ml of pentane are added dropwise with stirring over the course of 2 hours. A white precipitate forms at the dropping point, which quickly dissolves in the large excess of methylamine. The reaction mixture is allowed to warm to room temperature overnight with stirring. Colorless hydrochlorides precipitate out. The polymer soluble in pentane is separated from the precipitated methylammonium chloride by filtration. The precipitate is washed three times with 20 ml of pentane. The pentane is distilled off from the filtrate at room temperature in vacuo (10 mbar). A highly viscous, colorless liquid remains.
IR (KBr): 3475: v (NH), 2955: v _as (CH), 2890: v _s (CH), 1381: v (BN), 929: v (Si-N), 755: v (Si C).

Example 8 Aminolysis from DADB

130 ml of methylamine dried over molecular sieve (4 A) are placed in a 500 ml three-necked flask with dropping funnel, pressure relief valve and magnetic stirrer at -78 ° C. 16.1 g of MADB dissolved in 120 ml of pentane are added dropwise with stirring over the course of 2 hours. A white precipitate forms at the dropping point, which quickly dissolves in the large excess of methylamine. The reaction mixture is allowed to warm to room temperature overnight with stirring. Colorless hydrochlorides precipitate out. The polymer soluble in pentane is separated from the precipitated methylammonium chloride by filtration. The precipitate is washed three times with 20 ml of pentane. The pentane is distilled off from the filtrate at room temperature in vacuo (10 mbar). A highly viscous, colorless liquid remains.
IR (KBr): 3455: v (NH), 2961: v _as (CH), 2918: v _s (CH), 1383: v (BN), 1261: δ _s (CH ₃ ), 825: v (Si N), 778: v (Si-C).

Example 9 Pyrolysis of a polymer from Examples 5 to 8 into an amorphous ceramic powder

The polymer is placed in a boron nitride boat. First it will be in Argon flow heated at 150 K / h to 700 ° C, held at 700 ° C for 2 h and cooled to room temperature at 150 K / h. Then they will be in Nitrogen stream heated to 300 ° C / h up to 1500 ° C, 2 hours at 1400 ° C held and cooled to 150 K / h to room temperature.

The resulting ceramic consists of coarse to fine-pored black Fragments. The X-ray powder diffractograms of the four new ones Networks demonstrate that all samples are X-ray amorphous after pyrolysis are.

Elemental analysis from Example 7 (mass percent): Si: 26.3, B: 8.9, N: 36.3, C: 18.7, E: 3.9.

Example 10 Representation of a borosilazane-oligomer mixture

500 ml abs. Pentane are cooled to -78 ° C and then 200 ml Condensed methylamine in the cooled solvent. Under strong 50 ml of MADB or DADB are then diluted with 100 ml of abs. Pentane, added dropwise within an hour. After removing the Cold baths are observed in two phases; the upper one contains that  Oligomer mixture, dissolved in pentane, which contains the lower one Methylammonium chloride, dissolved in liquid methylamine. The approach is going warmed to room temperature overnight, taking the excess Methylamine evaporated. The now crystallized methylammonium chloride filtered off under protective gas and with 3 × 50 ml abs. Washed out pentane. The solvent is removed from the combined filtrates in vacuo deducted. A viscous liquid is obtained at room temperature Oligomer.

Example 11 Representation of a polyborosilazane

One obtained by aminolysis of MADB or DADB according to Example 10 Oligomer mixture is in an inert gas atmosphere at 50 ° / h to 200 ° C heated. After a holding time of 3 hours, the material is left on Cool to room temperature and connect the reaction flask to one Still. Now under vacuum at 50 ° / h to 150 ° C. heated and maintain this temperature until none Pass over by-products more. Then the temperature is increased during Increased to 200 ° C for 1 h. After a holding time of 3 hours, you leave again cool to room temperature and get a solid, brittle, colorless, clear product.

Example 12 Rheological characterization of a DADB polyborosilazane

The viscosity is first measured on a rotary rheometer Temperature range from 70 to 100 ° C determined. From an Arrhenius Application results in a viscosity of 100 Pa.s. at 88.6 ° C at At this temperature, oscillation tests are carried out. One determines first by varying the deformation amplitude γ from 0.01 to 10 den Range of linear viscoelasticity (this ranges up to γ = 0.7) and then by varying the oscillation frequency from 0.1 to 100 Hz at γ = 0.1  the course of the elasticity module G 'and the storage module G ". G' increases during the test from 55 Pa to 54000 Pa; G "rises from 0.3 Pa 150 Pa. This results in a loss factor (tan δ) of 200 at ω = 1 Hz.

Example 13 Production of SiBNC green fibers from one according to the previous ones Examples produced and characterized polyborosilazane

The polyborosilazane is filled into a heatable pressure vessel, at 90 ° C melted and by exposure to pure nitrogen (p = 4 to 8 bar) through a capillary nozzle (∅ 300 µm). The exiting Polymer thread is wound onto a godet (take-off speed 300 m / min) and filed.

Example 14 Curing of green fibers produced according to Example 13 in a batch process with ammonia or amines

The green fibers are placed in a batch reactor in which an atmosphere of pure NH ₃ or of ethylenediamine-containing N ₂ (EDA content between 0.5 and 1.5%) is set. After 24 hours of aging at room temperature, the temperature of the reactor is increased to 60 ° C. and the aging is continued for another 24 hours. The hardened green fibers can then be pyrolyzed at 1200 ° C without defects (melting, sticking).

Example 15 In situ shaft hardening of green fibers during the spinning process

The polyborosilazane is spun into green fibers as explained in Example 13. During the process, however, a mixture of N ₂ with approx. 1-2% trichlorosilane is introduced into the spinning shaft. It must be ensured by means of a suction device that no trichlorosilane gets to the spinneret. The spun and hardened green fibers can then be pyrolyzed at 1200 ° C.

Claims (33)

1. Compound of the general formula (I)
R _x Hal _3-x Si-NH-BR _y Hal _2-y ,
in which R each independently represents a hydrocarbon radical having 1 to 20 carbon atoms,
Hal is independently Cl, Br or I,
x = 1 or 2 and
y = 0 or 1. 2. Connection according to claim 1, characterized, that Hal means Cl every time it occurs. 3. A compound according to claim 1 or 2, characterized in that R each independently represents a hydrocarbon radical having 1 to 3 carbon atoms, a C ₁ -C ₂₀ alkyl group, a phenyl group or a vinyl group on each occurrence. 4. A method for producing a connection according to one of claims 1 to 3, characterized in that
that a compound of formula (II)
R _x Hal _3-x Si-NH-SiR ₃ ,
in which R each independently represents a hydrocarbon radical having 1 to 20 carbon atoms,
Hal each independently means Cl, Br or I and
x = 1 or 2,
with a compound of formula (III)
BR _y Hal _3-y ,
wherein R and Hal have the meanings given above and
y = 0 or 1,
at a temperature between -100 ° C and + 25 ° C. 5. A method for producing a connection according to one of claims 1 to 3, characterized in that
that a compound of formula (II)
R _x Hal _3-x Si-NH-SiR ₃ ,
in which R each independently represents a hydrocarbon radical having 1 to 20 carbon atoms,
Hal each independently means Cl, Br or I and
x = 1 or 2,
with a compound of formula (III)
BR _y Hal _3-y ,
wherein R and Hal have the meanings given above and
y = 0 or 1,
in a molar ratio of 1: 1 to 1:10. 6. The method according to claim 4 or 5, characterized, that Hal means Cl every time it occurs. 7. The method according to any one of claims 4 to 6, characterized in that R on each occurrence independently represents a hydrocarbon radical having 1 to 3 carbon atoms, a C ₁ -C ₂₀ alkyl group, a phenyl group or a vinyl group. 8. Process for the preparation of a compound of formula (II)
R _x Hal _3-x Si-NH-SiR ₃ ,
wherein R each independently represents a hydrocarbon radical having 1 to 20 carbon atoms and
Hal means Cl, Br or I.
and x = 1 or 2,
characterized in that R _x SiHal _4-x and R ₃ Si-NH-SiR _{3 are} implemented. 9. Process for the preparation of a compound of formula (II)
R ₂ HalSi-NH-SiR ₃ ,
wherein R each independently represents a hydrocarbon radical having 1 to 20 carbon atoms and
Hal means Cl, Br or I
characterized in that R ₂ SiHal ₂ and
R ₃ Si-NH-SiR ₃ in a molar ratio of 1: 1 to 1.5: 1. 10. Process for the preparation of a compound of formula (IIa)
R ₂ HalSi-NH-SiR ₃ ,
wherein R each independently represents a hydrocarbon radical having 1 to 20 carbon atoms and
Hal means Cl, Br or I
characterized in that R ₂ SiHal ₂ and R ₃ Si-NH-SiR _{3 are} reacted at a reaction temperature of 40 ° C to 60 ° C. 11. The method according to claim 9 or 10, characterized, that Hal means Cl. 12. The method according to any one of claims 9 to 11, characterized in that R represents a hydrocarbon radical with 1 to 3 carbon atoms, a C ₁ -C ₂₀ alkyl group, a phenyl group or a vinyl group on each occurrence. 13. Borosilazane compound of the general formula (IV)
(R'R "N) _q R _x Hal _3-xq Si-NH-BR _y Hal _2-yz (NR'R") _z ,
wherein R 'and R "each independently represent hydrogen or a hydrocarbon radical having 1 to 20 carbon atoms,
R each independently represents a hydrocarbon radical having 1 to 20 carbon atoms,
Hal is independently Cl, Br or I,
q = 0.1 or 2,
x = 1 or 2,
y = 0 or 1 and
z = 0, 1 or 2,
with the proviso that
q + z ≧ 1, x + q ≦ 3 and y + z ≦ 2. 14. Borosilazane compound according to claim 13, characterized, that Hal means Cl every time it occurs. 15. Borosilazane compound according to claim 13 or 14, characterized in that R represents a hydrocarbon radical with 1 to 3 carbon atoms, a C ₁ -C ₂₀ alkyl group, a phenyl group or a vinyl group on each occurrence. 16. Borosilazane compound according to one of claims 13 to 15, characterized in that R ', R "are each independently selected from C ₁ -C ₃ alkyl, C ₁ -C ₃ alkenyl, in particular vinyl, and phenyl. 17. A method for producing a borosilazane compound according to a of claims 13 to 16, characterized, that a compound of formula (I) which is as in one of the Claims 1 to 3 is defined, with at least 4 to 8 times molar amount of a compound of formula (V) R'R "NH at a Temperature from -80 ° C to + 300 ° C implemented. 18. Oligo or polyborosilazane compound, obtainable by reaction a compound of formula (I) as in any one of claims 1 to 3 defined, or / and a compound of formula (IV), as in a of claims 13 to 16, with a compound of formula (V) R'R "NH, or by polymerizing a compound of the formula (I) or the formula (IV), characterized, that they have the structural feature C-Si-N-B, Si-N-B-C or / and C-Si-N-B- C. 19. Process for the preparation of an oligo or Polyborosilazanverbindung, characterized, that a compound of formula (I), as in one of the Claims 1 to 3 defined, and / or a compound of the formula (IV) as defined in any one of claims 13 to 16 polymerized or with a compound of the formula (V) R'R "NH. 20. The method according to claim 19, characterized, that the polymerization as a polycondensation at a Temperature of ≦ 200 ° C. 21. The method according to claim 19 or 20  characterized, that the polymerization is carried out at a reduced pressure of 90 kPa. 22. A process for the preparation of a silicon carbobornitride ceramic, characterized in that a borosilazane compound of the formula (IV) according to any one of claims 13 to 16 or an oligo- or polyborosifazane compound according to claim 18 in an inert or an amine and / or NH ₃ -containing The atmosphere is tempered at temperatures between 800 ° C and 1700 ° C. 23. Silicon carbobornitride ceramic, obtainable by a process according to Claim 22 characterized, that in ceramics C-Si-N-B, Si-N-B-C or / and C-Si-N-B-C Structural units are present and the elements Si, N, B and C to more than 93% by mass are included. 24. Silicon carbobornitride ceramic, obtainable by a method according to Claim 23 characterized, that there are Si-N-B structural units in the ceramic and the Elements Si, N, B and C to more than 93 mass%, in particular to more than 97 mass% are included, with the proviso that C ≧ 3 mass%. 25. Silicon carbobornitride ceramic according to one of claims 23 or 24 characterized, that it is an amorphous silicon carbobornitride ceramic powder is.   26. A process for producing a composite ceramic made of SiC, Si ₃ N ₄ and BN, characterized in that a silicon carbobornitride ceramic according to one of claims 23 to 25 is aged at temperatures <1700 ° C. 27. The method according to claim 26, characterized, that made an at least partially crystalline composite ceramic becomes. 28. Composite ceramic, obtainable by a process according to claim 26 or 27 by crystallization of a silicon carbobornitride ceramic according to one of claims 23 to 25, characterized in that SiC, Si ₃ N ₄ and BN are present in a molecularly disperse distribution. 29. Use of a borosilazane compound according to one of the claims 13 to 16 or an oligo or polyborosilazane compound Claim 18 for the production of ceramic fibers, ceramic Coatings, ceramic moldings, ceramic foils or / and ceramic microstructures. 30. Use of ceramic materials according to one of the Claims 23 to 25 or 28 for the production of ceramic Molded articles, ceramic fibers, ceramic coatings or ceramic microstructures. 31. Use according to claim 29 or 30, characterized, that microstructures by injection molding or lithographic processes be generated.   32. Use according to claim 29 or 30, characterized, that from the ceramic fibers fabrics or braids be made. 33. Use of a borosilazane compound according to one of the claims 13 to 16 in a chemical vapor deposition (CVD) or physical vapor deposition (PVD).