JPS62241809A - Manufacture of ceramic material - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing ceramic materials, which may be refractory carbides, nitrides, borides or silicides of metallic or non-metallic elements. , silicon, zirconium,
It can be a carbide or nitride of titanium, hafnium, tantalum or tungsten, or a boride or silicide of aluminum, zirconium, titanium, hafnium, tantalum or tungsten, or it can be silicon boride.

Refractory carbide or nitride particles are so-called ear
Bothermie is traditionally produced by a reaction in which an intimate mixture of carbon and an oxide of a metallic or non-metallic element is heated in an inert atmosphere to produce a carbide or in an atmosphere of nitrogen. For example, in the production of silicon carbide, an intimate mixture of carbon and silica is reacted according to the total equation.

5in2+3C→sic+2CO.

The problems associated with carcharothermic reactions are illustrated by the problems associated with silicon carbide production. Thus, in the production of silicon carbide, an intimate mixture of carbon and silica is fired in an inert atmosphere at temperatures that can be as high as 2500°C, and this firing is carried out in an electric furnace. In this conventional method, the required stoichiometric proportions of silica and carbon are easily achieved, i.e. 3 moles of carbon for each mole of silica, 37.5% by weight carbon and 62.5% by weight i. % silica. However, in this conventional method it is difficult to achieve the necessary intimate contact between carbon and silica in order to be able to produce products of homogeneous composition, i.e. products of homogeneous composition on a molecular scale. There is a problem in one respect. In particular, the particles produced, which are nominally silicon carbide, become contaminated with unreacted silica and/or carbon. This contamination can occur even when using very small particles of silica and carbon, such as silica sol and carbon black. Furthermore, it is difficult to produce silicon carbide particles with very small dimensions, such as sub-micron dimensions, using this traditional method.

When producing silicon nitride by a carbothermal reaction, silica is similarly reacted with carbon to achieve total reduction of the silica, and the reduction product is reacted with nitrogen according to the full equation 3SiO2+ ℃+ 2N2-* 5i5N4+ ℃O
.

Carcharothermal reactions to produce silicon nitride suffer from the same problems associated with carbothermal reactions to produce silicon carbide.

JP-A-60-12-2706 describes an improved silica reduction method that is said to produce silicon nitride with high yield and high content of α-8i and N4. In this improved method, a powder mixture consisting of one layer of silica powder, 0.4 to 4 parts of carbon powder, and 0.005 to 1 part of silicon nitride powder is placed on the mixture in 1. Calcinate at 1350-15500 C in a non-oxidizing atmosphere containing nitrogen or gaseous nitrogen compounds passed at a rate of Q~2.0 cw/sec. The silicon nitride in the powder mixture serves to promote the formation of silicon nitride crystals.

Silicon nitride can be produced by direct reaction between silicon and nitrogen according to the following equation:

3si + 2N → Si 3N,.

However, this method has the disadvantage that generally only coarse particles of silicon nitride can be produced. For example, the process may be carried out by reacting silicon tetrachloride with ammonia. This conventional process also has the disadvantage of producing large amounts of ammonium chloride which results in the presence of chloride impurities in the silicon nitride produced.

There are a number of known methods for producing refractory borides and silicides of metallic or non-metallic elements, in particular for producing particulate hard borides and silicides.

For example, particulate metallic or non-metallic element oxides may be mixed and reacted with particulate carbon and particulate boron carbide in an inert atmosphere at elevated temperatures.

Alternatively, particulate mixtures of boron oxide and oxides of metallic or nonmetallic elements and carbon or of boron and metallic or nonmetallic elements can be reacted at elevated temperatures in an inert atmosphere. One example of producing such a boride is provided by a method for producing titanium boride according to the following reaction scheme: TiO2+ B2O3+ 5C-+ TiI12
+5CO.

In such conventional methods, the close contact required between the components of the granular mixture to produce particles of homogeneous composition, such as between oxides of metallic or nonmetallic elements, boron oxide, and carbon, is avoided. The necessary intimate contact (i) is problematic in that it is difficult to achieve.Furthermore, the particles of boride of metallic or non-metallic elements produced are of course dependent on the composition of the granular mixture used in the production process. This contamination can result in contamination with unreacted metallic or nonmetallic elements or their oxides, as well as unreacted boron, boron carbide, or boron oxide. Even when used, it is difficult to produce metallic or non-metallic boride particles with very small dimensions, eg, less than 1 micron, using these methods.

Silicides of metallic or nonmetallic elements can be produced by the same method as described for the production of borides, except that boron, boron carbide, or boron oxide.
Using L-en silicon or silicon carbide or silica or silicates, for example, silicides can be produced by heating in a granular mixture of silicon and metallic or non-metallic elements *all in an inert atmosphere. However, these conventional methods suffer from the same problems associated with the production of borides of metallic or nonmetallic elements.

It has been proposed to produce refractory carbides, such as carbon-arsenic, by pyrolysis of the elements of ceramic materials, i.e., in the case of silicon carbide, organic polymeric materials containing all silicon and carbon but no oxygen. . In such conventional methods, the polymeric material is first coked to convert the organic components of the polymeric material to carbon, which is then reacted with silicon in a pyrolysis reaction. This is not a traditional charcoal reaction where carbon and silica are reacted. The purpose of using such polymeric materials is to manufacture them from polymeric materials.

The objective is to achieve a more intimate mixture of the elements of the ceramic material, such as silicon and carbon, in the coked product than can be achieved with a mixture of silica and carbon, for example in the case of silicon carbide. However, the proportions of carbon and silicon in the coking product are very different from the theoretically required proportions, which has a significant negative effect on the purity of the resulting silicon carbide.

``Pre-ceramic''
) J An early example of polymeric materials is U.S. Patent No. 2.6'? 7
, No. 029, which describes the copolymerization of a 7lyl-substituted monomer, such as trimethylsilylstyrene, with another monomer, such as divinylbenzene or ethylvinylbenzene, to obtain a crosslinked resin. , describes the production of polymeric materials by pyrolyzing mosquito resin to obtain solids containing carbon and silicon.

Another example of a ``pre-ceramic'' material is the pyrolysis of medium sacilane to decamethylcyclo (Yajima et al., Ch.
(Yajima, 1976* Nature 2
Vol. 73, p. 525). These calgesilanes can be melt spun into fibrous materials from which refractory silicon carbide can be produced by heating at high temperatures. The reaction that takes place at high temperature is between silicon and carbon, and is not a traditional carbothermal reaction, ie, the reaction between silica and carbon described above. This conventional process has the disadvantage that the silicon carbide product is impure.

A more recent example of a "gray ceramic" material from which refractory carbides can be produced is provided by Japanese Patent Publication No. 57-17412, which describes halodane compounds or alkoxides of silicon, vanadium, zirconium, tantalum or tungsten. A method is described in which the reaction product is reacted with a carbohydrate and the resulting reaction product is calcined. Rodan compound or 7A/:j? For example, Stem4.
zroe/2.5i (OC2H5), 5L (OC2
H5), C2H5,5t(OC2H5)2(CH,)2
゜z r(oc4Ht)4-vict2(oC2
H5)4, the carbohydrate can be, for example, a monosaccharide or a polysaccharide such as dulcose, plaquedose, arabinose, millet or cellulose. The above reaction can be carried out in the absence of a solvent, but in the presence of a solvent, for example aromatic solvents such as benzene or toluene; aliphatic solvents such as heptane, heptane or octane; or the presence of halogenated aromatic or aliphatic solvents. It is preferable to carry out below.

The coking reaction product is produced by heating the reaction product in an inert atmosphere and calcining the coking reaction product at a temperature in the range of 700-2700°C in an inert atmosphere. The coking reaction product can be ground into a fine powder before firing.

Although the above publication states that the reaction between a halodane compound or alkoxide and a carbohydrate can be carried out in a solvent and that the solvent can be used in an amount sufficient to dissolve or suspend the carbohydrate, the present invention The authors have found that the disclosed carbohydrates are not soluble in solvents and can only be suspended in particulate form in solvents, so that the reaction described above produces a reaction product of homogeneous composition. or the reaction product is not produced in a particularly easy-to-handle form. The refractory carbide produced from the reaction product therefore also does not have a homogeneous composition. Furthermore, the proportions of carbon and silica in the coking reaction product are also very different from the theoretically required proportions.

Thermo chimica Acta
A recent development is the production of silicon carbide by pyrolysis of rice husks, as described in Acta), Vol. 1 (1984), pp. 77-86. Rice husks are composed of silica and cellulose, and when pyrolyzed, a mixture of silica and carbon is obtained. Rice husk has a very high surface area, and this high surface area, along with the intimate contact between carbon and silica in the pyrolyzed rice husk, allows silicon carbide to be formed by subsequent pyrolysis at relatively low temperatures. Production of silicon carbide is 2
It can be carried out by a process method, in which the temperature at relatively low temperatures, e.g.
The rice husks are coked by heating in the absence of air at 0'C to decompose the cellulose into amorphous carbon, and the thus coked rice husks are then heated at a high temperature, e.g. 1500C.
Silicon carbide is produced by heating at temperatures above C and in an inert or reducing atmosphere. The presence of iron in the rice husk accelerates the reaction and iron can be introduced by soaking the rice husk in a solution of ferrous sulfate followed by ammonia. The molar ratio of silica to carbon in coked rice husks is generally about 1:4.7, i.e. there is a substantial excess of carbon over the stoichiometrically required ratio of 1:3. ,
The presence of iron influences this proportion and allows a proportion closer to that required schematically to be achieved. However, although the production of silicon carbide from rice husks results in the production* of particles and whiskers or short fibers, it is also possible to produce silicon carbide in various different physical forms, such as particles, filaments, films or coatings. This is not a reasonable method. In practice, there is a lack of control over the physical shape of the silicon carbide produced.

Silicon nitride can also be produced by raising rice La and reacting it with nitrogen at 'fc temperatures. Such a method is described in U.S. Pat.
The method includes the steps of heating the rice husks to a temperature within the range of 0'C, and exposing the heated rice husks to gaseous nitrogen until the silica in the rice husks changes to silicon nitride. The production of silicon nitride can be carried out in a two-step process, in which rice husk is coked by heating at relatively low temperatures, e.g. at a high temperature for example 1300
A kilogram of silicon nitride is produced by heating at a temperature of about °C in a nitrogen atmosphere. However, as in the case of silicon carbide production, the production of silicon nitride from rice husks requires the production of particles,
Products in the form of whisker crystals or short fibers are produced, but silicon nitride in various different physical forms, such as particles, long fibers, films or coatings, is not a foolproof process. In practice, there is a lack of control over the physical shape of the silicon nitride produced.

The problems associated with these aforementioned methods of producing all-ceramic materials can be summarized with reference to the production of refractory carbides. That is, the quality of the refractory carbide produced by these aforementioned methods depends, at least in part, on the composition and structure of the precursor material from which the carbide is produced, and on the processing conditions. For example, when producing silicon carbide from a mixture of silica and carbon by a carbon thermal process, there is no problem in achieving the overall ratio of silica to carbon required to produce silicon carbide, but fine particles The interaction between silica and carbon in a carbon thermal process is necessary to produce a silicon carbide product that has a homogeneous composition on a molecular scale and is free of unreacted silica and/or carbon. It is impossible to achieve close contact.

Reaction products containing carbide elements such as silica and carbon, e.g. reaction products produced by a carcharothermic reaction between silica and carbon, e.g. in the production of refractory carbides by pyrolysis of polymeric materials. The elements may be present in the required proportions to produce a ceramic material substantially free of impurities and in the required physical form, for example in the form of small particles, fibers, films or coatings. Refractory chars can be difficult to produce; i.e., the reaction products can be cumbersome and difficult to convert into the desired physical form. Refractory chars can be produced by pyrolysis of rice husks. In some cases, there is again little control over the physical shape of the refractory carbide.

Ceramic materials such as refractory carbides and nitrides have been used for many years in applications such as abrasives and in tool manufacturing. Although the quality of the ceramic material could not be of critical importance in these applications, the quality of the ceramic material and its physical form could be of critical importance. There are other uses for ceramic materials that have more recent developments. These more recently developed uses of ceramic materials include uses such as engineering materials and electronic applications.

The present invention provides a method for producing ceramic materials that are substantially free of impurities and is suitable for producing ceramic materials of uniform quality and composition.

According to the present invention, in the method for producing a ceramic material, two or more first reactants containing at least one compound of a metal element or a non-metal element having two or more groups reactive with hydroxyl groups are used. a second compound containing at least one organic compound having more hydroxyl groups;
preparing an oxygen-containing polymeric product by reacting with a reactant containing carbon and an oxide of a metallic or non-metallic element, and heating the polymeric product in an inert atmosphere. producing a coking product, heating the coking product to carry out a carcharothermic reaction between an oxide of a metallic or non-metallic element and carbon, and thus producing a ceramic material; and the second reactant such that the weight proportion of carbon and oxides of metallic or non-metallic elements in the coking product is the proportion theoretically required to form the ceramic material tm. A method of manufacturing a ceramic material is provided, comprising selecting a ceramic material in the range of 50 to 150.

The type of ceramic material produced by the process of the invention is largely determined by the conditions under which the coked product is heated and the composition of the coked product. For example, a coking product containing carbon and an oxide of a metallic or nonmetallic element can be heated in an inert atmosphere to produce a carbide of a metallic or nonmetallic element, or the coking product can be heated in an inert atmosphere to produce a carbide of a metallic or nonmetallic element; A nitride of a metal element or a non-metal element can be produced by heating in an atmosphere or in an atmosphere of a reactive metal nitride.

Alternatively, the polymeric product prepared by the method of the invention comprises a metallic or non-metallic element, boron or silicon, oxygen and carbon and is prepared from the polymeric product. The first reactant contains a compound of a metallic element or a non-metallic element and boron or silicon, such that the coking product comprises carbon, an oxide of a metallic or non-metallic element, and an oxide of boron or silicon. In the case of containing a compound of
The coking product can be heated at elevated temperatures in an inert atmosphere to produce borides or silicides of metallic or nonmetallic elements.

The stated proportions of carbon and oxides of metallic or non-metallic elements are in the coking product, which coking product is produced by heating the polymeric product collectively in an inert atmosphere. It is produced by the process of oxidation and consists of an intimate mixture of carbon and an oxide of 1 m or more of a metallic element or a non-metallic element. The stated proportions of carbon and oxides of metallic or nonmetallic elements are derived from heating a polymeric product containing the theoretically required proportions of carbon, oxygen, and metallic or nonmetallic elements. It is important to understand that not all of the proportions occur in the coking product. Rather, it is the proportion of carbon and oxides of metallic or nonmetallic elements that actually forms in the coking product upon total heating of the polymeric product.

The inventors have discovered that during heating of the polymeric product to produce the coked product, some of the elements present in the polymeric product are substantially depleted. As a result, if the polymeric product contains the theoretically required proportions of carbon, oxygen, and metallic or non-metallic elements, heating the polymeric product will actually The resulting proportions of carbon and oxides of metallic or non-metallic elements can differ significantly from the proportions theoretically required in the coking product.

GB 2.1'7', 276 A discloses that the organotitanate and the carbon precursor weight are present in such a way that titanium and carbon are present in the schematically required circumstances. titanium carbide powder by forming a mixture with a polymer and heating the mixture to a temperature sufficient to convert the mixture to rr and to pyrolyze the polymer to form carbon and to form titanium carbide. It is stated that it is manufactured.

The chemical requirement is the amount of the element present in the titanate and polymer, not the amount of the element present in the carbon-containing pyrolysis product.

In order to suppress the proportion of carbon and oxides of metal or non-metal elements in the coking product produced from the polymeric product, the first reactant is reactive with hydroxyl groups. All compounds of metallic elements or non-metallic elements that can contain one or more groups and also have only one reactive group It can contain one or more. Similarly, the second reactant may contain one or more organic compounds having two or more hydroxyl groups, and may also contain one or more organic compounds having only one hydroxyl group. can.

The theoretically required proportions of carbon and oxides of metal or non-metallic elements in the coking product depend, of course, on the type of metal or non-metal, and the It depends on the stoichiometry of the carbothermal reaction and on the type of ceramic material to be produced. For example, the above oxide has the following formula MO2, e.g. Sin□, Tie
When trying to produce a carbide in the case of □ and ZrO2 (with MO□), the carbothermal reaction can be expressed as the following formula: The theoretically required molar ratio with the oxide is 3:1.
It is. In the case of oxides of silicon, titanium and zirconium, the theoretically required weight proportions of carbon and oxide are: 5i02 62.54 carbon: 5i02 l:1.67 carbon 37.5 TiO26g, 9g Carbon: Tio2 1:2.2
2) Carbon 31.1 whisper ZrO2'7'1-44 Carbon: ZrO21:3
．． 42 Carbon 22.64 The stoichiometry of carcharothermic reactions can be different, such as in the reaction between carbon and oxides of tantalum to produce tantalum carbide.

Ta205+7C→2TaC+5CO In this case, the theoretically required molar ratio of carbon to oxide is 7:1, which corresponds to g4i! in the coking product prepared from the polymeric product. %T! 1205 and 1
Corresponds to 6-fold carbon, i.e. 1:5.25 carbon:
In the production of 6-silicon nitride corresponding to a 11L proportion of TazOs, a coking product consisting of a mixture of silica and carbon is produced in the initial stage of heating, and this mixture is then subjected to the overall reaction equation which can be expressed as: : React with nitrogen according to the % formula %.

This equation represents the total reaction that would occur and is not intended to represent the reaction that could actually occur.

Theoretically required stoichiometric ratio of 1:2 silica:
The molar proportion of carbon, i.e. 71.4 fi weight ratio of silica and 28.6 weight ratio of carbon, corresponds to a weight ratio of 1:2.5 carbon:5I02 in the coking product. In the case of the elements titanium, vanadium, zirconium and hihafnium, these oxides can be represented by the formula MO2, these nitrides can be represented by 2MN, and the overall reaction is : It can be expressed as % expression %.

The theoretically required chemical ratio in the coking product is a 1:2 oxide:carbon molar ratio, which corresponds to the following weight ratio:

TiO76.9% Carbon: TlO21:3.33
Carbon 23.1 VO77,54 Carbon J: VO21:3-44 Carbon 2
2.54 Zr02g3.7% carbon”, Z ro 2 1
: 5, l 3 carbon 16.3 嗟11f0289.8 Sorry carbon: I(fo21:8J
.

In the case of elements consisting of carbon 10.2, boron and aluminum, these oxides are 2M20. These nitrides can be represented by the formula MN, and the overall reaction can be represented by the following formula: %Formula %.

The theoretically required stoichiometric ratio in the coking product is a 1:3 oxide:carbon molar ratio, which corresponds to the following weight ratios:

B20. 65.94 Carbon: n2o5 1:1
．． 93 Carbon 34.1 Al2O573,9 Carbon: Al2O5l:2.
In the case of vanadium oxide with the 83 carbon 26.1 formula v205 and vanadium nitride with the 2 VN, the total reaction can be expressed as:

An oxide:carbon molar ratio of 1:5 is theoretically required, corresponding to the following amounts and weight ratios:

V2O575.2% Carbon: V2O51:3.0
3 Carbon 24.8 When attempting to produce nitrides of metallic or non-metallic elements, the theoretically required stoichiometry of carbon and oxides of the elements in the coking product must be Percentages can be calculated in a similar manner.

In the method of the invention, the proportion of the first reactant and the PJ2 reactant is such that the proportion of carbon and oxides of metallic or non-metallic elements in the coking product that can be produced is such that a ceramic material is produced. 50' of the theoretically required ratio
Select from a range of 6 to 150 units. For example, when trying to produce silicon carbide from charcoal ash between silica and carbon, the theoretically required ratio is l:
Corresponds to a ratio of carbon to silica of 1.67 or α6:1, and the theoretically required ratio of 5011 to +50'l corresponds to a ratio of carbon to silica of l:0.84 to l:2.51. This corresponds to the ratio with silica, which is 54.3 weights of carbon and 45.6 weights of silica! This corresponds to a composition ranging from 1 to 28.5% by weight of carbon and 71.5% by weight of silica. When attempting to produce silicon nitride, the theoretically required weight ratio of carbon and silica is l: 2.5, and the range of 50% to 150% of the theoretically required ratio is l:2.5. :
This corresponds to a ratio of carbon to silica ranging from 1.25 to 1:3.75, which is 44.4% carbon and 55% silica.
．． 6 heavy squares ~ carbon 2+, +11* and 1 tsuka 70.9
Corresponds to the composition of the heavy leaf group.

The theoretically required proportions of carbon and oxides of metallic or nonmetallic elements in the coking product which is subsequently to be converted into borides or silicides of metallic or nonmetallic elements can be similarly estimated. obtain.

The closer the ratio of carbon to oxides of metallic or non-metallic elements in the coking product is to the theoretically required ratio, the higher the purity of the ceramic material produced from the coking product by a carbothermal reaction. For this reason it is preferred that the ratio of carbon to oxide is in the range of 75 to 1254 the theoretically required ratio, and 90'i to 110 of the theoretically required ratio. % range is more preferable. The selection of reactants and proportions of reactants to achieve this desired range of proportions is discussed in detail below.

In the case of silicon carbide, the aforementioned range of 90-110% corresponds to a weight proportion of carbon nisilica in the range of I: 1.59-1.75, which is 3 g of carbon, 1 kqh of 6-weight and 61.4 of silica. heavy carbon to carbon 36.4 heavy and silica 63
．． This corresponds to a composition in the range of over 6 weight. In the case of silicon nitride, the above range of 90 to 1104 is I: 2.38
~I: Corresponds to a carbon percentage in the range of 2.63%, which ranges from 29.6% carbon and 70.4% silica to 27.5% carbon and 72.5% silica. corresponds to the composition of

The metallic or non-metallic elements must be such that they can form a hepteramic material.

For example, when producing refractory carbides or nitrides, metallic or nonmetallic elements such as aluminum, boron,
Silicon, zirconium, titanium, hafnium, tank ^
Or could be tungsten, or a refractory boride or silicide? The metallic or non-metallic element can be aluminum, zirconium, titanium, hafnium, tantalum or tungsten, or the metallic or non-metallic element if silicon boride is to be produced. may be a mixture of boron and silicon. The method of the invention is not limited to the production of ceramic materials of the specifically mentioned metallic or non-metallic elements.

The first reactant contains at least one compound of a metal element or a non-metal element having at least two groups reactive with a hydroxyl group, and may also contain a group that is not reactive with a hydroxyl group.

For example, the first reactant compound has the following formula: (wherein X is a group reactive with hydroxyl groups, Y is a group not reactive with hydroxyl groups, M is a metallic element or a nonmetallic element, n is an integer of at least
m is zero or the order of the ship). The group X can be a halide, such as a chloride or a bromide, an amide, or an alkoxy group, such as a group of the following formula: OR, in which R is, for example, an alkyl group containing from 1 to 8 carbon atoms, such as methoxy, ethoxy or It can be a cytoxy group. The group Y may be present in compounds of metallic or non-metallic elements, such as hydrocarpyl radicals, alkyl, cycloalkyl, aryl or alkaryl radicals. Particular groups of such groups include methyl, ethyl, propyl, cyclohexyl and benzyl groups.

The group Y can be an oxidizing group, for example the compound of a metallic or non-metallic element can be an oxidizing halide.

Specific examples of compounds of metallic or non-metallic elements in which all of the groups present are reactive with hydroxyl groups are: tetramethoxysilane, tetraethoxysilane, tetraethoxyzirconium, interethoxytantalum, venter n-propoxytantalum, tetrachloride Silicon, silicon tetrabromide, titanium tetrachloride, zirconium tetrachloride, dichlorjetoxysilane, chlortriethoxy zirconium, dichlorotributoxy tantalum, boron tetrachloride, boron triynepropoxide, aluminum triynepropoxide and aluminum trichloride. be.

Examples of compounds of metallic or non-metallic elements containing groups that are reactive with hydroxyl groups and groups that are not reactive with hydroxyl groups include methyltrimethoxydisilane, methyltriethoxysilane, ethyltriethoxysilane,
Dimethyljethoxysilane, dimethyldimethoxysilane, diphenyljethoxysilane and phenyltrimethoxysilane and equivalent compounds of silicon oxychloride and other metallic or non-metallic elements.

If it is desired to produce a boride or silicide of a metallic or nonmetallic element, the first reactant may include a compound of boron or silicon and a compound of a metallic or nonmetallic element other than boron or silicon. It is possible.

Generally, compounds of metal elements or non-metal elements do not contain hydroxyl groups. This is because hydroxyl group-containing compounds of metallic or nonmetallic elements that can form refractory carbides are generally unstable, or they cannot even exist as hydroxides or The compounds may easily condense to form polymeric products or they may exist as hydrated oxides rather than as hydroxides, such as in the case of hydrated alumina. This is because it will be put away.

The second reactant contains at least one organic compound having two or more hydroxyl groups. The organic compound can be, for example, an aliphatic, aromatic or cycloaliphatic compound. Examples of suitable aliphatic organic compounds containing two hydroxyl groups are the glycols ethylene glycol, propylene glycol, butylene glycol and hishyethylene glycol. Examples of suitable aliphatic organic compounds containing two or more hydroxyl groups are glycerol, trihydroxybutane and trihydroxytetanthane. tU of cycloaliphatic organic compounds containing at least two hydroxyl groups include dihydroxycyclohexane and trihydroxycyclohexane. Preference is given to aromatic organic compounds containing two or more hydroxyl groups. This is because the compound contains a large proportion of carbon, and when incorporated into a polymeric product, the desired proportion of carbon and the oxidation of metallic or non-metallic elements can be obtained in the coke ratio product produced from the product. This is because it is useful for achieving things. Examples of such aromatic organic compounds include dihydroxytoluene and hydrosinaphthalene.

Since the reaction between one or more metal or non-metallic compounds and one or more organic compounds to produce a polymeric product is of the type of condensation polymerization, the first reactant contains at least two A metal or non-metallic compound or a plurality of such compounds containing reactive groups must be included, and the second reactant must be an organic compound or a plurality of such compounds containing at least two hydroxyl groups. A plurality of compounds must be included.

Various means are conceivable for controlling the proportion of carbon and oxides of metallic or nonmetallic elements in the coking product produced from the polymeric product. For example, if a relatively high proportion of carbon is required in the coking product, a second
The reactants can include organic compounds containing cyclic groups such as aromatic or alicyclic groups or unsaturated groups. This is because when converting polymeric products made from organic compounds into coking products, the loss of carbon is not large, ie, the yield of carbon is high.

Suitable organic compounds include dihydro-sinaphthalene and dihydroxycyclohexane. On the other hand, organic compounds containing aliphatic groups tend to have high carbon losses when polymeric products made from such compounds are converted to coking products; It is not significantly determined by chain length. That is, if a coked product containing a high proportion of carbon is desired, the use of aliphatic glycols and polyols, at least in high proportions, is not preferred. The production of polymeric products and coking products containing a high proportion of carbon can be achieved by using organic compounds containing a single hydroxyl group as part of the second reactant, such as furfuryl alcohol, cyclohexanol, phenol or It is also facilitated by the use of additional reactants comprising cresols. An organic compound containing a single hydroxyl group may react with a metal or non-metallic compound and become pendant from the polymeric product chain rather than as a unit within the polymeric product chain. form one structural unit. Particularly advantageous are organic compounds containing unsaturated moieties, especially those containing unsaturated cyclic groups, such as furfuryl alcohol. This is because certain compounds produce carbon in the coking product at an odious rate.

If a relatively high proportion of fully open elemental or non-metallic element oxides is desired in the coking product, the second reactant may contain or consist of an aliphatic glycol or a polyol such as ethylene glycol or glycerol. Additional reactants may be used, including compounds of metallic or non-metallic elements having a single group reactive with hydroxyl groups and/or as part of the first reactant. Such compounds react with organic compounds to form units pendant from the polymeric product chain rather than as units within the polymeric product chain.

Examples of such compounds include trialkylalkoxysilanes such as trinotylethoxysilane and corresponding compounds of titanium, zirconium, vanadium, tantalum and other metallic or non-metallic elements.

The proportion of $J1 reactant and second reactant used in the production of the polymeric product and the proportion of additional reactant, if present, as necessary to produce the desired coked product. It is necessary to isolate and analyze the coking product in order to determine whether a certain proportion and, in some cases, oxides of carbon and metallic or non-metallic elements in the coking product are present. It may be necessary to experiment with and vary the proportions and types of reactants until the desired proportions are achieved. Thereafter, in operating the process of the present invention, it is unnecessary to isolate the coked product during the production of the ceramic material, although it may be isolated if desired.

In coking products made from polymeric products, the proportion of carbon can be analyzed by igniting the coking product in an oxidizing atmosphere and determining the amount of carbon dioxide produced, and the proportion of carbon can be determined by igniting the coking product in an oxidizing atmosphere and determining the amount of carbon dioxide produced. The amount of oxide can be determined by chemical analysis. The relative proportions of the first reactant, second reactant, and additional reactants, if present, and the nature of these reactants are determined by the amount of experimentation required to prepare the polymeric product. the desired proportions of carbon and oxides of metallic or non-metallic elements in the coked product, the latter proportion being determinable by the analytical means described above. .

The conditions for reacting a compound of a metal element or a non-metal element with an organic compound are determined depending on the type of these compounds, and in some cases, depending on whether or not a solvent for these compounds is used. Vigorous agitation of the reaction mixture of these compounds is desirable to aid in the production of a polymeric product of homogeneous composition.

Especially when the compound of a metal element or a non-metal element is an easily hydrolyzable compound, for example, when the compound of a metal element or a non-metal element is an alkoxide, for example, when the core compound is an alkoxide of silicon or titanium. It may be appropriate or even necessary to carry out the reaction in a dry, inert atmosphere. Some halides of metallic or non-metallic elements, such as 5iel, and T 1e14
is also an easily hydrolysable compound.

The temperature at which the reaction is conducted depends on the particular reactants. That is, disilanes and glycols and polyols in silicon tetrahalides or tetraalcohols With reagents such as ethylene glycol and glycerol, the reaction can proceed at or near room temperature, but with other reagents and the reaction If the reaction is carried out in a solvent, it may be necessary to carry out the reaction with increased polarity. The reaction temperature is generally above the boiling point of the solvent, but temperatures above the boiling point can also be used.

Reaction force '/fJ, t When the reaction is a transesterification reaction in which alcohol is removed, such as the reaction between a silicon alkoxide and a hydroxy compound, the reaction temperature is above the boiling point of the alcohol removed in the reaction. is preferred.

The reaction can be assisted by the presence of a suitable catalyst in the reaction mixture, for example if the reaction is a transesterification reaction, by the presence of an acid catalyst. Suitable catalysts for such transesterification reactions are known in the art.

In operating the process of the invention, it is particularly preferred that the reactants are selected to be miscible with each other or to be soluble in a common solvent. When the reactants are miscible, the reaction produces a polymeric product of homogeneous composition, and which has a composition that is more homogeneous than the product produced from reactants that are not miscible with each other. is manufactured.

If the reactants are not miscible with each other, the reaction is preferably carried out in a common solvent for the reactants in order to produce a polymeric product of homogeneous composition. Even if the reactants are miscible with each other, the reaction may be carried out in a common solvent for the reactants. Because the polymeric product is in the form of a solution, and thus is particularly easy to handle, the polymeric product is soluble in or miscible with the reactants or miscible with common solvents. It is also desirable that it be sexual. Such a solution can be spray dried to produce a small particle size polymeric product, which can then be converted into a small, homogeneous particle size ceramic material. The solution of the polymeric product can be used as an adhesive, for example for other refractory particles, and the product can then be converted into a ceramic material. The solution can be used as a coating composition or a film-forming composition from which coatings or films of ceramic materials can be produced. The product solution can be spun into fibers.

It is preferred to use miscible reactants or reactants that are soluble in a common solvent. This is because coking products having a particularly desirable structure are produced themselves from polymeric products by reaction of reactants that are miscible with each other or are dissolved in a common solvent. This is because it is manufactured.

The coking product thus produced comprises a particularly homogeneous mixture of carbon and oxides of metallic or non-metallic elements; in another embodiment of the invention, metallic or non-metallic elements are present in the carbon matrix. A coking product is provided that contains regions of elemental oxides.

domain of oxides of metallic or nonmetallic elements
s) have small dimensions and can hardly be described as particles. In fact, when coking products are examined by transmission electron microscopy, regions of oxides of metallic or non-metallic elements have large dimensions of less than 50 nanometers (nm) or maximum dimensions of less than 10 nm or even 25 nm. This shows that carbon exists in the form of a continuous matrix.

The series of compounds of metallic or non-metallic elements and organic compounds containing hydrothousyl groups which are miscible with each other includes tetraethoxysilane and glycerol, which may also contain furfuryl alcohol, and in some cases furfuryl alcohol. Also contains tetraethoxysilane and diethylene glycol and triethoxyboron and glycerol when heated to slightly elevated temperatures.

N-methylgerolidone is combined with tetraethoxysilane and a hydroxyl group-containing organic compound in some cases.
- Glycerol mixed with furfuryl alcohol is a suitable solvent for use with 8 compounds of 1,5-naphthalene diol optionally mixed with furfuryl alcohol. N-methylpyrrolidone is a suitable solvent for use with mixtures of triethoxyboron and diethylene glycol, optionally containing furfuryl alcohol.

Ethanol is a suitable solvent for use with various different compounds of metallic or non-metallic elements and hydroxyl-containing organic compounds, such as titanium tetrachloride and glycerol, titanium tetraethoxide and glycerol, and in some cases Titanium tetraethoxide and glycerol mixed with furfuryl alcohol, aluminum trichloride and glycerol, aluminum triimpropoxide and glycerol sometimes mixed with furfuryl alcohol, zirconium tetrachloride and glycerol and furfuryl alcohol, tetraethoxysilane Cyclohexane-+, a-diol, resorcinol or 1.3.
It is a suitable solvent for use with 5-trihydroxybenzene and hafnium tetrachloride and glycerol.

In order for the polymeric product produced in the above reaction to be in a particularly easy-to-handle form, if the reaction is carried out in a solvent, the polymeric product must be soluble in the solvent in which the reaction is carried out. Preferably or the product is soluble in another solvent. To achieve this solubility, it is desirable to carry out the reaction for a shorter period than that required to achieve complete reaction between the reactants in order to avoid undesirable amounts of cross-linking. Such cross-linking may occur if the reaction proceeds to or near completion and will affect the solubility of the polymeric product. Similarly, when the reaction is carried out in the absence of a solvent, the polymeric product is in a more easily handled form, especially since it is in a form that can be dissolved in the solvent before further processing. It may be desirable to run the reaction for a shorter period of time than necessary to achieve complete reaction. However, if the polymeric products produced are difficult to handle and are especially insoluble, they can be ground, for example, to a powder before further processing.

Before the polymeric product is used in the next step of the process of the invention, unreacted reactants, if any, are removed, e.g. by the use of a solvent that selectively removes these reactants or from solution. The polymeric product becomes cloudy free of unreacted reactants by precipitation of the polymeric product or by any other conventional means. However, it may be unnecessary to remove these unreacted reagents since they can be effectively removed from the polymeric product in subsequent stages of aqueous aqueous treatment.

If IJ is prepared in an inert atmosphere, it is heated in a vacuum or in an inert gas or nitrogen atmosphere to form a coke containing carbon and one acidic acid of a metallic element or a non-metallic element. However, prior to this heating, when the polymeric product is in the form of an IJ solution dissolved in a solvent, it can be spray dried to produce a small particle size polymeric product. This can then be converted into a coked product of small and uniform particle size. The solution can be used as an adhesive, for example for other refractory particles, and the polymeric product can be coked. The solution can be used as a coating composition or a film-forming composition from which a coating or film of a coked product can be produced.A solution of a polymeric product. can be spun into fibers.

The temperature at which heating is carried out to produce the coked product will depend on the nature of the organic component of the polymeric product, but generally temperatures up to 600°C are sufficient, although higher temperatures, e.g. Temperatures up to It should be carried out for a sufficient period of time M such that there is little or no weight loss.

In a step subsequent to the aqueous aqueous process, the coking product is heated to a temperature of m degrees above the temperature at which the coking step takes place, but above the temperature at which the carbothermal reaction takes place to produce the ceramic material. Temperatures at about 1200' Ct may be sufficient, but higher temperatures are preferred.

Temperatures down to 0C may be required. The selection of the heating atmosphere depends on the type of ceramic material to be manufactured. If carbides or borides or silicides are to be produced, heating is suitably carried out in an inert atmosphere, for example in vacuum or in an atmosphere of inert gas. Alternatively, if nitrides are to be produced, heating is suitably carried out in an atmosphere containing nitrogen or a reactive nitrogen-containing monomer. Heating may be carried out until there is little or no further weight loss.

The heating steps of the aqueous droplets, i.e. the heating steps for producing coked products from the polymeric products and the heating steps for producing ceramic materials from the coked products, are carried out substantially continuously without isolation of the coked products. Can be operated with a heating program. For example, heating can be carried out by gradually increasing the temperature and by selecting an appropriate atmosphere to carry out the heating at a particular temperature.

The invention is illustrated by the following implementation sequence.

Example 1 41.649 ml of tetraethoxysilane and 9.87.9 ml of furfuryl alcohol were charged to a reaction vessel and the resulting solution was heated under nitrogen for 4 hours until no more ethanol was distilled off. Then 13,511 grams of glycerol was added to the solution, the solution was heated and the ethanol was distilled off. A dem-like solid formed at the base of the reaction vessel, and the solid yield was 666 wt., calculated based on the ethanol distilled off.

The reaction vessel was then heated on a water bath under vacuum and r9 was formed in the reaction vessel. This group consists of industrial methylated spirit acetone, 1.1. It was soluble in l-trichlorethylene and N-methylpyrrolidone.

The weighed sample was placed in a quartz tube, and the quartz tube and contents were heated in a nitrogen atmosphere using the time/temperature schedule listed in Table 1 below to periodically measure the weight loss of the sample. It was measured.

Table 1 The yield of the solid coking product obtained was 32.8% by weight of the solid charged in the quartz tube, and the solid contained 36.4 parts by weight of saliva C and 63.4 parts by weight. Contains a large amount of sio□. The weight ratio of carbon to silica in the coking product was +: 1.7 a or 0.57:l.

The theoretical stoichiometric ratio required is I: 1.6
7 (37,s heavy carbon and 62.5 weight 1 g'A of silica) or 0.6:1.0. That is, the coking product is deficient in carbon, and the ratio of carbon to silica is 964% of the theoretical stoichiometric ratio required for a carbothermal reaction.
Met.

Heating from room temperature to 400°C at a heating rate of 5°C per minute, then at a heating rate of IO''C per minute to 1600°C for 3 hours in an atmosphere of helium. The black, brittle solid was pyrolyzed.

The resulting product was examined by X-ray diffraction and Raman spectroscopy and was shown to contain β-8iC. The product also contained 3.0 wt. SiO2 and 2.1 wt. F# residual carbon.

Example 2 52.07 g of tetraethoxysilane and 24.53 g.
9 furfuryl alcohol,! Following the method of Example 1 except using glycerol = 15.3511,
The product in the form of a dark brown glue was removed from the reaction vessel C). This guru is 1. It was soluble in I,1-trichloroethane.

Repeat the heating method of Example 1 until the temperature reaches 46
A black solid was produced in poor yield, containing 39.2 wts carbon and 60.8 wts silica.

The weight ratio of carbon and silica is 1:1.55 or Q, 65
: I, and the ratio of carbon to silica was 108s, which is the stoichiometric ratio required for a carbothermal reaction.

Mf13 20.599 of tetraethoxysilane and 5.129 of furfuryl alcohol were charged to a reaction vessel and the resulting solution was stirred and heated under nitrogen until no more ethanol-h was distilled off. Glycerol of 6.801 was then added to the cooled solution, the solution was stirred and heated to 90"C, and the ethanol was distilled off. A mucous solid formed at the base of the reaction vessel, and the solid The yield was calculated to be 96.3 wt. based on the amount of ethanol distilled off.

The weighed solid sample was placed in a quartz tube, the quartz tube and its contents were heated under a nitrogen atmosphere according to the period/temperature schedule listed in Table 2 below, and the weight of the sample was measured. Losses were measured periodically.

Table 2 The yield of the obtained solid is 46.2% of the solid charged in the quartz tube.
The solid has a width of 30.0 and 70.0.
% by weight of SiO2. The weight ratio of carbon to silica in the coking product was 1:2.33. The required theoretical stoichiometric ratio is +: 2.5
(28.6 layers of carbon and 71.4 layers of silica). That is, in the coking product, the weight ratio of carbon to silica is 107% of the required theoretical stoichiometric ratio.
．． It was 3rd place.

From room temperature to 400'C at a heating rate of 5°C per minute, then at a rate of 10°C per minute to 1650'C.
The black solid was pyrolyzed by heating in an alumina tube at a ramp rate of 1650°C for 6 hours in an atmosphere of nitrogen.

Examination of the resulting product by infrared and X-ray diffraction analysis showed it to contain α-8i3N4 and a minor silica contaminant.

Examples 4-9 Coked products were prepared according to the method as described above in six separate examples.

Example 4 166.4 g of tetraethoxysilane (o, g mol)
and 55.2. ! 9 (0.6 mol) and the resulting mixture was stirred and heated until no more ethanol was distilled out of the mixture. A clear gelatin was obtained, and the yield of ethanol was 864 sq. of the theoretical amount, based on the glycerol used.

A weighed sample of fk was placed in a quartz tube and the contents were placed under an atmosphere of dry nitrogen and heated to a final temperature of 800'C for a period of 7 hours. A black, easily friable product was obtained with a yield of 25.5 Ftes;
Heavy! Contains fly carbon and 84 layers of strength. That is, in the coking product the ratio of carbon to silica is l:
5.25, or the theoretical stoichiometric ratio of 31.8 required for the carbothermal reaction to silicon carbide.

5J! Example 5 Tetraethoxysilane (04 mo9) of 83.2.9 and 4
8.49 glycerone (0.53 mol) and practice row 4
The reaction was carried out using the following method. The yield of ethanol was 82% of the theoretical amount based on the amount of glycero-h used.

The method of Example 4 was followed by heating the role generating force to soo'c to obtain a black, easily friable material with a yield of 42 layers. The coking product contains 17.5% carbon and 82°5
% by weight of silica. That is, the ratio of carbon to silica was I:4.71, that is, the ratio was 35.5, which is the theoretical ratio required for the carbonic reaction to silicon carbide.

Example 6 Following the method of Example 4, 52.1 g of tetraethoxysilane (0.25 moh) and 6'? , I g with glycerol (0.75 mol). The yield of ethanol is determined by IfK of the tetraethoxysilane used & 8
It was a whisper. The product is obtained as a clear viscous liquid,
When cooled to room temperature, it solidified into a solid roll. When the product is heated to goo'c by the method of Example 4, 16
．． A black porous solid was obtained in a yield of 6 wt. The coking product contains 17.7 tJ of carbon and 82.3% by weight.
of silica. That is, the ratio of carbon to silica is I
:4.65, that is, the theoretical stoichiometric ratio required for the carbothermal reaction to silicon carbide7) was 35.94.

Example 7 83.29 tetraethoxysilane (0.4 mol) and 1
0 - ethanolate 24.2 jJ mannitol (0
, 13 moles) were charged to a reaction vessel as used in Example 4. The reaction mixture was stirred and heated until no more ethanol was distilled out of the mixture.

A white, waxy solid was obtained, and the yield of ethanol was 80 liters, the expected value based on the amount of mannitol used.
It was 4.

A portion of the solid was placed in a quartz tube, and the contents were placed under an atmosphere of dry nitrogen and heated to 800'C for a period of ε hours to obtain a black, friable solid. The coking product is 13
．． Contains 4-fold Ik rumored carbon and 86.6-14 silica. That is, the ratio of carbon to silica in the coked product was I:6.46, or 25.84, the theoretical stoichiometric ratio required for the carbothermal reaction to silicon carbide.

Example 8 52.079 tetraethoxysilane (0.25 mol)
and 74.539 of furfuryl alcohol (0.25 mol) were charged to a reaction vessel as used in Example 4, and the resulting solution 7r was stirred and nitrogen evaporated until no more ethanol was distilled off. Heated to the bottom. 15.351 of glycerol (0.167 moA) was then added to the cooled solution and the solution was heated again under nitrogen until no more ethanol was distilled off. A brown color forms and hardens upon cooling, resulting in an overall yield of ethanol of the expected value based on the amounts of furfuryl alcohol and glycerol used.
It was 11# wide.

A portion of the cured resin was placed in a quartz tube and the contents were placed under an atmosphere of dry nitrogen and heated for 800 minutes over a period of 5 hours.
It was heated to C. The coked product obtained in a yield of 37.5 kg contained 39.2 parts by weight of carbon and 60.8 parts by weight of silica. Thus, the ratio of carbon to silica in the coking product was 1:5.5, or 107% of the theoretical stoichiometric ratio required for the carbothermal reaction to silicon carbide.

Example 9 to, ao g of tetraethoxysilane (0.05 mol),! =941 g of furfuryl alcohol (0.1 mol) were charged to a reaction vessel as used in Example 4, and the resulting solution was stirred and heated under nitrogen until no more ethanol was distilled off. . 5.3, '1' of naphthalene-1,5-diol (0.05 mol) and 20 w#t of N-methy^pyrrolidone as a solvent were added to a reaction vessel to form a slurry.

The mixture was heated under nitrogen until all solids dissolved to give a dark brown solution. Heating was continued until all of the ethanol produced in the reaction was removed by distillation. The overall yield of ethanol was 82% less than expected based on the amount of tetraethoxysilane used. The solvent was removed by distillation under reduced pressure.

The resulting product had a toffee-like consistency and was very dark brown in color. A portion of this product was placed in a quartz tube under nitrogen and heated to 8000C in a cage for a period of 7 hours. 5
The coked product obtained with a yield of 3.6 gm was 5o
It contained 11@* carbon and 20 wt 1 silica. That is, the ratio of carbon to silica in the coking product is 4:1.
That is, 666% of the theoretical stoichiometric ratio required for the carbothermal reaction to silicon carbide.

In the following Table 3, the proportions of the reactants used in Examples 4 to 9 and the proportions of carbon and silica in the coking product are given as the proportions of carbon and silica theoretically required for the production of silicon carbide. To summarize the effects of

Examples 4-7 and 9 are comparative examples and Example 8 provides a detailed explanation of the invention. Comparing Examples 4 to 6, when the organic hydroxy compound is an aliphatic hydrocarbon compound, i.e., glycerol, the organic hydroxy compound used in the production of the polymeric product and the first reactant, tetraethoxysilane. It is seen that changes in the ratio of carbon have little effect on the ratio of carbon to silica in the coked product made from the polymeric product. The ratio of carbon to silica is substantially lower than required. Example 7 shows that changing the type of aliphatic alcohol also has little effect.

On the other hand, Example 8 shows that the furfuryl alcoholic compound, which is also an unsaturated cycloaliphatic monohydroxy compound, is
When used in combination with glycerol as a reactant, it is possible to vary and control the ratio of carbon to silica in this coked product made from the polymeric product and still be able to maintain the ratio as theoretically required. Coking products with very similar carbon to silica ratios can be produced.

The coking products from Run 9'lj 4.8 and 9 were heated separately in a quartz tube in an atmosphere of helium at a heating rate of 5 °C per minute until a temperature of 1600 °C was reached, and The tube and interior were then heated at +600'C for 10 hours.

Example 8) The ceramic material produced from the coked product contained 92.1 parts by weight of β-8iC and 6.6 parts by weight of carbon.

As a comparison, the ceramic material made from the coking product of run f114 contained 24.4 wt. of β-8IC and 75.6 wt. of SiO□, with a very substantial amount of SiO2 in the ceramic material. This proportion is caused by the low proportion of carbon to silica in the coking product compared to the proportion theoretically required for a wide range of coal temperatures. As another comparison, the Northern ceramic material made from the coking product of Example 9 was 14.
Containing 9-fold iml of β-8iC and 85.11al of rumored carbon, the substantial contamination by carbon is due to the carbon to silica in the coking product compared to the ratio theoretically required for a carbothermal reaction. This is caused by the extremely high proportion of

Example 9110 The method of Example S is repeated except that an additional volume of ethanol (25 m
A), zirconium tetraethoxide (5
,0,V) and furfuryl 7' alcohol C2,699''
) and glycerol (6.21 g) were reacted. The polymeric product produced was in the form of a white solid.

The solid was heated to a temperature of 8000 C according to the method described in Example 1 to produce a coked product in the form of a black solid with a yield of 31.1 F/I, which was 25.3 F/I! - Contains 100% carbon and 74% zirconia. The weight ratio of carbon and zirconia is 1nia, 95 or 0
．． 34:1, but the theoretically necessary chemical ratio for a carbonothermic reaction is 1:3.42 or 0.29:
+ (22.6% carbon by weight and 77.4ii% zirconia). The carbon to zirconia ratio in the coked product of Gll et al. is 117.2 times greater than the theoretically required ratio.

The coking product was heated to 150 °C at a heating rate of 5 °C per minute.
Heated in vacuo to 0'C and then at 1500C for 2 hours.

X-ray examination of the resulting ceramic material showed that it consisted of zirconium carbide with graphite deposits and in some cases traces of zirconia. Chemical analysis showed that the zirconium carbide contained 21 g of carbon and sgH of zirconia.

Example 11 The method of Example 1 mff 1 l is followed, except that titanium tetrain zolo I oxide (28,399'I tofurfuryl alcohol A (5,14 g) and glycerol (4,84,!if
) and a polymeric product in the form of a dark brown rind was removed from the reaction vessel.

40°C according to the heating method of Example 1 up to a temperature of 800'C.
A coked product was produced with a yield of 0.011 Lt'A containing 29.4 g of carbon and 70.6 g of titania. The tit ratio of carbon and titania is l:',
40 or 0.42:I, and the required theoretical chemistries ratio is l: 2.22 or o, a s:
+ (31,06 double solid carbon and 68.9 true regular titania), Muti coking product has 1-im B-'''PIr + J + 7B end, and 11ΔI round paving. 93 of the theoretically stoichiometric proportions that are considered r?, -f, h
．． 3 I was disappointed.

Coking in vacuum from room temperature to SO'C at a heating rate of 50°C/min, then at a heating rate of 100C/min to 1600'C for 2 hours in vacuo. heated things.

The resulting ceramic material was examined by X-ray diffraction and showed to contain titanium carbide along with a small amount of Ttc2 which was removed. Inorganic analysis shows that the product is 9
It contained a Ttc of 9.71 and a TiO□ of 0.3 n.

Actual #Example 12 Tetraethoxysilane (2,440, OI) Tofu^
A polymeric product was prepared according to the method of Example 1 except that furyl alcohol (s7s, ol) and toglycerol (791.0 g) were used.

Repeating the heating method of Example 1 to 800°C produced a coked product with a yield of 35.0 kg, which was 39.
It contained 98 carbon atoms and silica of 98 carbon atoms and 98 carbon atoms. The 11 ratio of carbon to silica in the coked product I"il: 1.50 or 0.6721. The theoretical stoichiometric ratio required in the coked product is l: 1.67 or 0.60: l (37,5fold I1
4 carbon and 62.5 It4 silica).

That is, the weight ratio of carbon to silica in the coked product was 111.64, which is the theoretical stoichiometric ratio required for a carbothermal reaction.

The coking product was pyrolyzed by heating in helium from room temperature to 1600'C at a heating rate of 5°C/min and then at +600'C for 10 hours.

The resulting ceramic material, produced in a moderate yield of 30.7 kg, was examined by X-ray diffraction and was shown to contain β-8iC along with a small amount of α-8iC.

Analysis shows that the products are 92, +4 SiC and 6
．． Contains 6 carbon atoms.

EXAMPLE IZI+ 3 A polymeric product is prepared according to the method of Example 1, except that ethanol (25 t.
Dissolve in 1.3.5-1 lyhydroxybenzene (
7・Og) in a solution of aluminum insolone j? Oxide (10,29)i was added. The polymeric product was in the form of a white solid.

Repeat the heating method of Example 1 to a temperature of 800°C for 30
．． A coked product was produced with a yield of 6 F, containing 32.7 F of carbon and 67.2 F of alumina. The weight ratio of carbon and alumina is l:2.06
or 0.49:I, and the required theoretical stoichiometric ratio is 1:2.83 or 0.35:1 ('6.1 with 73.9 parts of carbon) 8120.). That is, the ratio of carbon to alumina in the coked product was +401 of the theoretical stoichiometric ratio required for a carbothermal reaction.

Coke is produced by heating at a heating rate of 5°C/min from 200°C to 500'C, then at a rising rate of 7°C/min from 200°C to 500'C, and by heating at 1600°C for 10 hours in nitrogen. The reaction product was thermally decomposed.

The resulting ceramic material, produced at a yield of 52.8 cm, was examined by X-ray diffraction and was shown to contain aluminum nitride. Chemical analysis showed that the product contained aluminum nitride and 9 parts by weight of carbon.

Claims (1)

[Claims] 1. In the method for producing a ceramic material, a first reactant containing at least one compound of a metallic element or a nonmetallic element having two or more groups reactive with hydroxyl groups, preparing an oxygen-containing polymeric product by reacting with a second reactant containing at least one organic compound having two or more hydroxyl groups;
heating the polymeric product in an inert atmosphere to produce a coked product containing carbon and an oxide of a metallic or non-metallic element; heating the coked product to produce a coked product containing the metallic element; or carrying out a carcharothermal reaction between an oxide of a non-metallic element and carbon and thus producing a ceramic material, the proportions of the first reactant and the second reactant being adjusted to match the carbon in the coking product. and the oxide of a metal element or a non-metallic element in a weight ratio within the range of 50 to 150% of the ratio theoretically required for manufacturing a ceramic material. A method of manufacturing a ceramic material consisting of: 2. The claim that the proportion of carbon and oxides of metallic or non-metallic elements in the coking product is in the range of 75 to 125% of the proportion theoretically required to produce the ceramic material. The method described in paragraph 1. 3. The claim that the proportion of carbon and oxides of metallic or non-metallic elements in the coking product is in the range of 90 to 110% of the proportion theoretically required to produce the ceramic material. The method described in Section 2. 4. The method according to any one of claims 1 to 3, wherein the metal element or nonmetal element is aluminum, boron/silicon, zirconium, titanium, hafnium, tantalum, or tungsten. 5. The method according to any one of claims 1 to 4, wherein the ceramic material produced is a carbide or a nitride. 6. The first reactant has the following formula: MX_nY_m (where X is a group reactive with a hydroxyl group, Y is a group not reactive with a hydroxyl group, M is a metal element or a non-metal element, n is an integer of at least 2 and m
is zero or an integer), the method according to any one of claims 1 to 5. 7. The method according to claim 6, wherein the group X in the first reactant is a halide, amide or alkoxy group. 8. The method according to any one of claims 1 to 7, wherein the second reactant is an aliphatic, aromatic, or alicyclic compound containing two or more hydroxyl groups. 9. The method according to claim 8, wherein the second reactant comprises ethylene glycol or glycerol. 10. The method according to any one of claims 1 to 9, which uses an additional reactant consisting of an organic compound having a single hydroxyl group. 11. The method according to claim 10, wherein the additional reactant comprises an organic compound having an unsaturated cyclic group. 12. The method of claim 11, wherein the additional reactant comprises furfuryl alcohol. 13. The method according to any one of claims 1 to 12, which uses an additional reactant consisting of a compound of a metal element or a nonmetal element having a single group reactive with a hydroxyl group. 14. The method according to any one of claims 1 to 13, wherein the reaction is carried out between a first reactant and a second reactant that are miscible with each other. 15. The method according to any one of claims 1 to 14, wherein the reaction is carried out in a common solvent for the first reactant and the second reactant. 16. A method according to any one of claims 1 to 15, wherein the polymeric product is produced in the form of a solution. 17. Claim 15 wherein the solvent is ethanol
or the method described in paragraph 16. 18. Claims 1 to 17 for producing a coked product by heating the polymeric product in an inert atmosphere.
The method described in any of the paragraphs. 19. The method of claim 18, wherein the polymeric product is heated in an inert atmosphere at temperatures up to 800°C. 20. Claims 1 to 19, wherein the ceramic material is produced by heating the coked product at a temperature equal to or higher than the temperature at which the coked product is produced by heating the polymeric product.
The method described in any of the paragraphs. 21. The method according to claim 20, wherein the coked product is heated to a temperature of 1800° C. or less. 22. The method according to claim 21, wherein the coking product is heated in an inert atmosphere to produce a carbide of a metal element or a non-metal element. 23. The method according to claim 21, wherein the coking product is heated in an atmosphere containing nitrogen or a reactive nitrogen-containing compound to produce a nitride of a metal element or a non-metal element. 24. Coking products containing regions of oxides of metallic or non-metallic elements in a carbon matrix. 25, the area of oxides of metal elements or non-metal elements is 500
25. A coked product according to claim 24 having a maximum dimension of less than a nanometer. 26, the area of oxide of metal element or non-metal element is 100
26. A coked product according to claim 25 having a maximum dimension of less than a nanometer.