JP3212400B2 - Composition for ceramic coating and coating method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic coating composition comprising a modified polysilazane as an essential component and capable of forming a coating film having excellent heat resistance, abrasion resistance and corrosion resistance, and a ceramic coating method using the same. .

[0002]

2. Description of the Related Art In order to obtain high heat resistance, abrasion resistance and corrosion resistance, organic coatings are not sufficient, and ceramic coatings are used. Conventionally, as a method of forming a ceramic coating, PVD (sputtering method, etc.),
CVD, sol-gel methods, polytitanocarbosilane-based coatings, poly (disil) silazane-based coatings, polysilazane-based coatings, polymetallosilazane-based coatings, and the like are known.

[0003]

The above-mentioned ceramic coating methods are known, but all have problems. That is, the apparatus is expensive in the PVD and CVD methods. In the sol-gel method, the required firing temperature is as high as 500 ° C. or higher. Low-temperature baking (4
(Less than 00 ° C.). Those using a poly (disil) silazane-based polymer have difficulty in construction and cause cracks. Polysilazane and polymetallosilazane coatings can be fired at 200 to 500 ° C, but firing at less than 300 ° C does not necessarily result in good film quality.

Accordingly, the present invention solves the above-mentioned problems in the prior art, and can be easily (by using less expensive alcohol and less expensive alcohol) by firing at a low temperature (50 ° C. to 350 ° C.). Excellent heat resistance, wear resistance, corrosion resistance,
An object of the present invention is to provide a coating composition that gives a dense coating film without cracks, and a method for applying the same.

[0005]

The present inventors have conducted intensive studies to solve the above problems, and as a result, by adding an easily available alcohol to polysilazane, the coating film of the adduct was air-cooled. It has been found that the curing reaction when firing in a medium is promoted, and a good coating is formed at a firing temperature lower than before.

Thus, according to the present invention, mainly the general formula (I):

[0007]

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(However, R ¹ , R ² , and R ³ each independently represent a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, an aryl group, or a group other than these groups in which carbon is directly bonded to silicon.) , An alkylsilyl group, an alkylamino group, or an alkoxy group, provided that R ¹ , R
^At least one of R ² and R ³ is a hydrogen atom. The number average molecular weight having a main skeleton composed of units represented by) is 100 to 50,000 polysilazane and alcohol (Aminoaru
Excluding calls. ) , The alcohol /
A ceramic coating composition comprising at least an alcohol-added polysilazane having a polysilazane weight ratio in the range of 0.001 to 2 and a number average molecular weight of about 100 to 500,000 is provided.

The alcohol-added polysilazane used as an essential component of the coating composition in the present invention is
A compound in which a hydrogen atom bonded to at least a part of silicon atoms in the entire skeleton of polysilazane reacts with an alcohol, and the silicon atom in polysilazane has a side chain group or a terminal group condensed with the alcohol. is there.

In the reaction between polysilazane and alcohol,
Alcohol (HO-R ⁴ : Alcohol) and the dehydrocondensation reaction occurs between the OH group of the polysilazane and the SiH group of the polysilazane, and a Si-OC bond is formed as described below.

[0011]

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The number average molecular weight of the alcohol-added polysilazane used in the present invention is 100,000 to 500,000, preferably 500.
It is in the range of 10,000 to 10,000. The method for producing an alcohol-added polysilazane used in the present invention comprises reacting polysilazane and an alcohol without a solvent or in a solvent. The alcohol used in the present invention is preferably an alcohol having a boiling point of 110 ° C. or higher. For example, butanol,
Hexanol, octanol, nonanol, methoxyethanol, ethoxyethanol, furfuryl alcohol and the like.

The polysilazane to be used may be any polysilazane having at least a Si—H bond or an N—H bond in the molecule. Not only polysilazane alone, but also a copolymer of polysilazane with another polymer or polysilazane with other polysilazane may be used. Can also be used as a mixture with the compound of formula (1). The polysilazane to be used includes a polysilazane having a chain, cyclic or cross-linked structure, and a polysilazane having a plurality of these structures in a molecule at the same time, and these can be used alone or as a mixture.

The following are typical examples of the polysilazane to be used, but are not limited thereto. In the general formula (I), those having a hydrogen atom at R ¹ , R ² and R ³ are perhydropolysilazanes, and their production methods are described, for example, in JP-A-60-145903, D. Seyf
erth et al. Communication of Am. Cer. Soc., C-13, January
1983. Has been reported to. What is obtained by these methods is a mixture of polymers having various structures, but basically contains a chain portion and a cyclic portion in the molecule,

[0015]

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Can be represented by the following chemical formula: An example of the structure of perhydropolysilazane is as follows.

[0017]

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In the general formula (I), R ¹ and R ^{2 represent} a hydrogen atom,
A method for producing a polysilazane having a methyl group at R ³ is described in D.
Seyferth et al.Polym.Prepr., Am.Chem.Soc., Div.Polym.Che
m ,. 25 , 10 (1984). The polysilazane obtained by this method has a repeating unit of-
It is a chain polymer and a cyclic polymer of (SiH ₂ NCH ₃ ) —, and neither has a crosslinked structure.

In the general formula (I), R ¹ and R ^{3 represent} a hydrogen atom,
A method for producing a polyorgano (hydro) silazane having an organic group at R ² is described in D. Seyferth et al., Polym. Prepr., Am. Chem. Soc.,
Div. Polym. Chem., 25 , 10 (1984);
-89230. The polysilazane obtained by these methods includes-(R ² SiHNH)
-As a repeating unit having a cyclic structure having a degree of polymerization of 3 to 5 or (R ³ SiHNH) _x [(R ² S
iH) _1.5 N] _1-X (0.4 <x <1) Some molecules have both a chain structure and a cyclic structure in a molecule represented by the chemical formula.

In the general formula (I), polysilazane having a hydrogen atom for R ¹ and an organic group for R ² and R ³ , R ¹ and R ²
Having an organic group and a hydrogen atom at R ³ is-(R ¹ R ²
SiNR ³ ) — is a repeating unit and the degree of polymerization is mainly 3
-5 ring structures. Next, representative examples of the polysilazane used other than the general formula (I) will be given.

Among polyorgano (hydro) silazanes, D. Seyferth et al., Communication of Am. Cer. Soc., C-1.
32, July 1984. Some have a crosslinked structure in the molecule as reported. An example is as follows.

[0022]

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A polysilazane (R) having a crosslinked structure obtained by ammonia decomposition of R ¹ SiX ₃ (X: halogen) as reported in JP-A-49-69717.
¹ Si (NH) _X), or R ¹ SiX ₃ and R ² ₂ S
Polysilazane having the following structure obtained by co-ammonium decomposition of iX ₂ can also be used as a starting material.

[0024]

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The polysilazane used has a main skeleton composed of the unit represented by the general formula (I) as described above, but the unit represented by the general formula (I) may be cyclized as is apparent from the above. In such a case, the cyclic portion becomes a terminal group, and when such cyclization is not carried out, the terminal of the main skeleton can be the same group as R ¹ , R ² , R ³ or hydrogen.

There is no particular restriction on the molecular weight of the polysilazane to be used, and any available polysilazane can be used. However, in view of reactivity with alcohol, R ¹ , R ² ,
And R ³ is preferably a group having small steric hindrance. That is, R
¹ is preferably an alkyl group of a hydrogen atom and C ₁ -C ₅ as R ² and R ^3, more preferably an alkyl group having a hydrogen atom and C ₁ -C _2.

The mixing ratio of polysilazane and alcohol is
So that the alcohol / polysilazane weight ratio is from 0.001 to 2, preferably from 0.01 to 1;
More preferably, it is added so as to be 0.05 to 0.5. If the amount of alcohol added is greater than this, the molecular weight of the polysilazane is too high to cause gelation, and if the amount is small, sufficient effects cannot be obtained.

The reaction can be carried out without solvent,
In general, it is better to use an organic solvent because the reaction control is more difficult than in the case of using an organic solvent and a gel-like substance may be generated. As the solvent, a hydrocarbon solvent of an aromatic hydrocarbon, an aliphatic hydrocarbon, an alicyclic hydrocarbon, a halogenated hydrocarbon, an aliphatic ether, an alicyclic ether, or an aromatic amine can be used. Preferred solvents include, for example, benzene, toluene, xylene, methylene chloride, chloroform, n-hexane, ethyl ether, tetrahydrofuran, pyridine, methylpyridine and the like, and particularly preferred solvents include xylene, pyridine, methylpyridine and the like. At the time of the reaction, the atmosphere is not particularly limited, but the reaction is usually performed in the air. However, it is not preferable that the humidity is such that the polysilazane deteriorates.

The reaction temperature can be varied over a wide range. For example, when an organic solvent is used, it may be heated to a temperature lower than the boiling point of the organic solvent, but it is necessary to obtain a solid having a high number average molecular weight. The reaction can also be carried out by subsequently heating the organic solvent to a boiling point or higher to distill off the organic solvent. The reaction temperature is generally 150 ° C. or lower, but normal temperature is preferred. In particular, when xylene is used as the solvent, since it is suitable as a coating solvent, there is no need for solvent distillation or solvent replacement. That is, it is only necessary to add alcohol to the xylene solution of polysilazane.

Although the reaction time is not particularly important, it is usually 1
It is about 50 hours. In general, the reaction is preferably carried out at around normal pressure. In the present invention, in order to prepare a coating composition using the above-mentioned alcohol-added polysilazane, usually, the alcohol-added polysilazane may be dissolved in a solvent.

Examples of the solvent include aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbon hydrocarbon solvents, halogenated hydrocarbons such as halogenated methane, halogenated ethane, and halogenated benzene, aliphatic ethers, and aliphatic hydrocarbons. Ethers such as cyclic ethers can be used. Preferred solvents are methylene chloride, chloroform, carbon tetrachloride, bromoform, ethylene chloride, ethylidene chloride, trichloroethane, halogenated hydrocarbons such as tetrachloroethane, ethyl ether,
Ethers such as isopropyl ether, ethyl butyl ether, butyl ether, 1,2-dioxyethane, dioxane, dimethyl dioxane, tetrahydrofuran, tetrahydropyran, pentanehexane, isohexane, methylpentane, heptane, isoheptane, octane, isooctane, cyclopentane, methylcyclopentane And hydrocarbons such as cyclohexane, methylcyclohexane, benzene, toluene, xylene, and ethylbenzene.

When these solvents are used, two or more kinds of solvents may be mixed to adjust the solubility of the alcohol-added polysilazane and the evaporation rate of the solvent. The amount (proportion) of the solvent used is selected so as to improve the workability depending on the coating method to be employed, and varies depending on the average molecular weight, molecular weight distribution and structure of the alcohol-added polysilazane. Therefore, the solvent in the coating composition is about 90% by weight. , And preferably at a solid content of 10 to 50% by weight.

The concentration of the solvent varies depending on the average molecular weight, molecular weight distribution and structure of the alcohol-added polysilazane, but good results are usually obtained in the range of 0 to 90% by weight.
In the present invention, a suitable filler may be added as needed. Examples of fillers include silica, alumina,
Examples include fine powders of oxide-based inorganic substances such as zirconia and mica, or non-oxide-based inorganic substances such as silicon carbide and silicon nitride. Depending on the application, aluminum, zinc,
Addition of a metal powder such as copper is also possible. Further examples of fillers include silica silica, quartz, novacurite, diatomaceous earth, and other silica-based materials: synthetic amorphous silica: kaolinite, mica, talc, wollastonite, asbestos, calcium silicate, aluminum silicate Glass bodies such as glass powder, glass spheres, hollow glass spheres, glass flakes, foam glass spheres: boron nitride, boron carbide, aluminum nitride, aluminum carbide, silicon nitride, silicon carbide, titanium boride, nitride Non-oxide inorganic substances such as titanium and titanium carbide: calcium carbonate: zinc oxide, alumina,
Metal oxides such as magnesia, titanium oxide, and beryllium oxide: barium sulfate, molybdenum disulfide, tungsten disulfide, carbon fluoride, and other inorganic substances: metal powders such as aluminum, bronze, lead, stainless steel, and zinc: carbon black, coke, Examples include carbon materials such as graphite, pyrolytic carbon, and hollow carbon spheres.

These fillers may be used alone or in various shapes such as needles (including whiskers), granules, and scales.
A mixture of more than one species can be used. Further, it is desirable that the particle size of these fillers is smaller than the film thickness that can be applied at one time. The addition amount of the filler is in the range of 0.05 to 10 parts by weight based on 1 part by weight of the alcohol-added polysilazane.
The range is 3 parts by weight. Further, the surface of the filler may be used after being subjected to a coupling agent treatment, vapor deposition, plating or the like.

The coating composition may contain various pigments, leveling agents, defoaming agents, antistatic agents, ultraviolet absorbers, pH adjusters, dispersants, surface modifiers, plasticizers, drying accelerators, if necessary. An anti-flow agent may be added. According to the present invention,
Similarly, there is provided a coating method using the coating composition as described above. This coating method is repeatedly applied once or twice or more to the above-mentioned coating composition on a substrate, and then baked to obtain silicon-nitrogen- It is characterized in that a coating film made of oxygen-based or silicon-nitrogen-oxygen-carbon-based ceramics is formed.

The substrate on which the coating composition is applied is not particularly limited, and may be any of metals, ceramics, plastics and the like. As a coating means as a coating, a usual coating method, that is, spin coating, dipping, roll coating, bar coating, brush coating, spray coating, flow coating or the like is used. Also, sand the base before applying,
If surface treatment is performed by degreasing, various blasts, etc., the adhesion performance of the coating composition is improved.

After coating by such a method and sufficiently drying, heating and baking are performed. By this baking, the alcohol-added polysilazane is crosslinked, condensed, or, depending on the baking atmosphere, oxidized and hydrolyzed to be hardened to form a tough coating. The calcination conditions vary depending on the molecular weight and structure of the alcohol-added polysilazane, but calcination is performed at a gentle temperature increase rate of 0.5 to 10C / min at a temperature in the range of 50C to 1000C. Preferred firing temperatures range from 250 ° C to 350 ° C. The firing atmosphere may be either in the air or an inert gas, but more preferably in the air. Oxidation of the alcohol-added polysilazane due to calcination in air or hydrolysis by water vapor coexisting in the air proceeds, and a tough coating mainly composed of Si—O bonds or Si—N bonds at the above low calcination temperature. Can be formed.

Depending on the type of the alcohol-added polysilazane to be coated, conversion to ceramics may be incomplete under limited firing conditions. In this case, the coated film after firing may be lengthened at a temperature of less than 50 ° C. It is possible to keep the time and improve the properties of the coating film. In this case, the holding atmosphere is preferably in air, and more preferably in humid air having an increased water vapor pressure. The holding time is not particularly limited, but it is practically appropriate that the holding time is 10 minutes or more and 30 days or less. Further, the holding temperature is not particularly limited, but a temperature of 0 ° C. or more and less than 50 ° C. is practically appropriate. Although it is naturally effective to maintain the temperature at 50 ° C. or higher, the heating operation at 50 ° C. or higher is defined as “firing” in the text. That is, after baking at a certain temperature for a certain period of time, it is also effective to bake for a long time by lowering the temperature to, for example, 50 ° C.,
This operation is a type of the “heating and firing” operation described above.

Oxidation of the alcohol-added polysilazane or hydrolysis by water vapor coexisting in the air further proceeds by holding in air, and the conversion to ceramics is completed. A covering film can be formed. According to the above method, the firing temperature can be lowered, and various problems caused by the high firing temperature can be reduced.

Further, depending on the type of the alcohol-added polysilazane to be coated, calcination at 50 ° C. or more is not performed at all, and the coated film after application is held for a long time under a condition of less than 50 ° C. to improve the properties of the coated film. It is possible to improve. In this case, the holding atmosphere is preferably in air, and more preferably in humid air having an increased water vapor pressure. The holding time is not particularly limited, but is 10 minutes or more and 30 minutes or more.
Within days is practically appropriate. Further, the holding temperature is not particularly limited, but a temperature of 0 ° C. or more and less than 50 ° C. is practically appropriate. Although it is naturally effective to maintain the temperature at 50 ° C. or higher, the heating operation at 50 ° C. or higher is defined as “firing” in the text. Oxidation of the alcohol-added polysilazane or hydrolysis by water vapor coexisting in the air proceeds by holding in air, and the conversion to ceramics is completed, and the toughness mainly containing Si—O bonds or Si—N bonds is obtained. This makes it possible to form a simple coating film. According to the above method, various problems caused by a high firing temperature can be significantly reduced, and in some cases, conversion to ceramics at around room temperature becomes possible.

[0041]

[Production of raw material perhydropolysilazane]

A four-necked flask having an inner volume of 11 was equipped with a gas blow-in tube, a mechanical stirrer, and a dewar condenser. After the inside of the reactor was replaced with deoxygenated dry nitrogen, 490 ml of degassed dry pyridine was placed in a four-necked flask and cooled with ice. Next, when 51.6 g of dichlorosilane was added, an adduct (SiH ₂ Cl.2C ₅ H ₅ N) as a white solid was formed. The reaction mixture was ice-cooled, and while stirring, 51.0 g of purified ammonia was blown through a sodium hydroxide tube and an activated carbon tube.

After completion of the reaction, the reaction mixture was centrifuged, washed with dry pyridine, and then filtered under a nitrogen atmosphere to obtain 850 ml of a filtrate. The solvent was distilled off from 5 ml of the filtrate to obtain 0.1 g of resinous solid perhydropolysilazane. The number average molecular weight of the obtained polymer was measured by freezing point depression method (solvent: dry benzene).
960. IR (infrared absorption) spectrum (solvent:
Concentration of dry o-xylene; perhydropolysilazane: 1
0.2 g / 1) has a wave number (cm ^-1 ) of 3340 (apparent extinction coefficient ε = 0.5571 g ^-1 cm ^-1 ) and an N of 1175
Absorption based on H; Absorption based on SiH at 2160 (ε = 3.14); SiH and SiNSi from 1024 to 820
Based on the absorption. ¹ H NMR (proton nuclear magnetic resonance) spectra (60 MHz, solvent CDCl ₃ / standard substance TMS) all show broad absorption. That is,
δ 4.8 and 4.4 (br., SiH); 1.5 (b
r. , NH) was observed. A pyridine solution of this inorganic silazane (concentration of inorganic silazane, 5.24% by weight)
100 ml was placed in a pressure-resistant reaction vessel having an internal volume of 300 ml, and the reaction was carried out while stirring at 90 ° C. for 3 hours in a nitrogen atmosphere and in a closed system. During this time, a large amount of gas was generated. The pressure increased by 1.0 kg / cm ² before and after the reaction. After cooling to room temperature, 200 ml of dry ethylbenzene was added, the pressure was 3 to 5 mmHg, and the temperature was 50 to 50 mmHg.
After removing the solvent at 70 ° C., 4.68 g of a viscous liquid was obtained. This powder was soluble in toluene, tetrahydrofuran, chloroform and other organic solvents. The number average molecular weight of the viscous liquid was 1,320 as measured by GPC. As a result of analyzing the IR spectrum (solvent: ethylbenzene), the wave number (c
m ^-1 ) NH-based absorption of 3350 and 1175; 2
Absorption based on SiH of 170;
It was confirmed to show absorption based on H and SiNSi. Further, when the ¹ H NMR spectrum (CDCl ₃ , TMS) of the polymer powder was analyzed, each of them showed a wide absorption. That is, δ4.8 (br, SiH
₂ ), δ 4.4 (br, SiH ₃ ), δ 1.5 (br, N
H) absorption was observed. (SiH ₂ ) / (SiH ₃ )
= 4.1.

Reference Example 2 (Evaluation of ceramic formation during firing) In general, during firing of polysilazane, breaking of Si—R ₁ , N—R ₂ (R ₁ and R _{2 each} represent a hydrogen atom or an alkyl group) bond And S
The formation of i-N, Si-O bonds (the latter is limited to firing in an oxidizing atmosphere) occurs, and polysilazane is silicon nitride,
Converted to ceramics such as silicon oxynitride and silica. This process is called ceramicization. In this Comparative Example or Example, the polysilazane was mainly changed to silica because the calcination was performed in the air atmosphere. However, semi-quantitative evaluation of the progress of the ceramic formation was performed by the IR method.

The polysilazane obtained in Reference Example 1 was diluted with o-xylene to a concentration of 20% by weight. This solution was applied (2000 rpm, 20 seconds) on a silicon wafer having a diameter of 5 inches and a thickness of 0.5 mm using a spin coater to obtain a coating film having a thickness of about 0.5 μm. The IR spectrum of this coating film is shown in Reference FIG. 1 (spectrum). Next, when this coating film was heated at 300 ° C. for 1 hour in an air atmosphere,
The R spectrum changed as shown in FIG. Here, the SiH residual ratio and the SiO / SiN ratio were determined by the following method.

SiH residual rate = (SiH absorbance after heating /
SiH absorbance before heating) × 100 (%) SiO / SiN ratio = SiO absorbance after heating / S after heating
iN Absorbance Both values are indicators of the progress of ceramic formation. The smaller the residual ratio of SiH and the larger the ratio of SiO / SiN, the more advanced the ceramic formation.

Here, the characteristic absorptions of SiN, SiO and SiH were about 840, 1160 and 2160 cm ^-1 respectively. The absorbance was calculated as follows: Absorbance = log ( _Io / I). (Refer to FIG. 1 for the definitions of I _o and I.) Table 1 shows the obtained SiH residual ratio and SiO / SiN ratio.

Example 1 (Synthesis of alcohol-added polysilazane) Perhydropolysilazane obtained in Reference Example 1 (Perhydropolysilazane Type-2, PHPS-2 manufactured by Tonen; number average molecular weight ≒ 1)
To 100 g of a 20% xylene solution of (300) was added 2.0 g of n-hexyl alcohol (manufactured by Tokyo Chemical Industry Co., Ltd.), and the mixture was reacted at room temperature for 2 hours while stirring. The number average molecular weight of this solution was measured by GPC.
1350. In addition, as a result of the IR spectrum analysis, it was confirmed that CH-based absorptions having wave numbers (cm ^-1 ) of 2960, 2940, and 2870 appeared as compared to before the reaction with n-hexyl alcohol. In addition, ¹ H-
As a result of NMR spectrum (CDCl ₃ ) analysis, δ = 3.
7,1.4 absorptions were newly observed (δ = 1.4
N-H). Among these absorptions, the absorption at δ = 3.7 is based on Si—O—CH _2, which indicates that n-hexyl alcohol has been added to polysilazane.

(Evaluation of ceramic formation and coating)
This solution was used as a coating solution and had a diameter of 4 inches and a thickness of 0.1 mm.
A 5 mm silicon wafer was coated with a spin coater (4000 rpm, 20 seconds) to obtain a coating having a thickness of about 0.5 μm. Next, this coating film was placed under an air atmosphere at 350
C. for 1 hour, and the degree of progress of ceramic formation was evaluated by IR. The residual ratio of SiH = 0 (%), SiO / Si
The N ratio was 48 (FIG. 2). Comparative Example 1 On the other hand, when a coating solution of polysilazane to which no n-hexyl alcohol was added was applied and evaluated by the same process, the residual ratio of SiH was 8%, and the ratio of SiO / SiN was 2.6 (FIG. 3). Example 2 In the same manner as in Example 1, 10% by weight of furfuryl alcohol was added to the perhydropolysilazane obtained in Reference Example 1. When this furfuryl alcohol-added perhydropolysilazane was calcined at 350 ° C. for 1 hour in an air atmosphere, the residual ratio of SiH was 0% and the ratio of SiO / SiN was 26. Further, these fired coating films were treated with a mixed solution of 18 ml of 49% hydrofluoric acid (manufactured by Daikin Industries, Ltd.) and 1763 ml of 61% nitric acid (manufactured by Komune Chemical Co., Ltd.). In Example 2, 1540 ° / min, 1950 ° / min, 1260 ° / min
min. The results are summarized in Table 1. Table 1 Sintering Sintering SiH Etching temperature Time Residual rate SiO / rate (° C) (h) (%) SiN ratio (Å / min) ───────────────── ───────────────── Example 1 350 10 48 1540 Comparative Example 1 350 18 2.6 1950 Reference Example 2 300 1 17 1.36-Example 2 350 10 28 1260

[0049]

According to the present invention, it is possible to obtain a ceramic coating having excellent heat resistance, abrasion resistance and corrosion resistance and good adhesion to a substrate with less trouble and less costly alcohol. , With or without calcination at unconventional low temperatures. The composition of the present invention is suitable as a surface protective agent for metals, ceramics and the like, as well as plastic materials and electronic components unsuitable for high-temperature treatment. In particular, hard coating agents for plastics, coating agents for suppressing gas permeation of synthetic resin films and containers, protective films and insulating films for semiconductors, such as passivation films, interlayer insulating films, chip coat films, etc., semiconductor sealants, and liquid crystal displays It can also be used as a body undercoat film or alignment film.

[Brief description of the drawings]

FIG. 1 is an IR spectrum diagram of a ceramic evaluated in Reference Example 2.

FIG. 2 is an IR spectrum diagram for evaluating ceramics in Comparative Example 1.

FIG. 3 is an IR spectrum diagram for evaluating ceramics in Example 1.

Claims (2)

(57) [Claims] 1. A compound of the general formula (I): (However, R ¹ , R ² and R ³ are each independently a hydrogen atom,
An alkyl group, an alkenyl group, a cycloalkyl group, an aryl group, or a group in which, other than these groups, a group directly bonded to silicon is carbon, an alkylsilyl group, an alkylamino group, or an alkoxy group. However, at least one of R ¹ , R ² and R ³ is a hydrogen atom. ) Having a main skeleton consisting of units represented by the following formulas and having a number average molecular weight of 100 to 50,000 and an alcohol (excluding amino alcohol).
Good. ) , A composition for ceramic coating containing at least an alcohol-added polysilazane having an alcohol / polysilazane weight ratio in the range of 0.001 to 2 and a number average molecular weight of about 100 to 500,000. 2. The composition for coating according to claim 1, which is repeatedly applied to a substrate once or twice or more, and then heated to 50 ° C.
A coating method characterized by forming a coating film made of silicon-nitrogen-oxygen or silicon-nitrogen-oxygen-carbon ceramics by firing at the above temperature.