JPS6311381B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a coating composition comprising a semi-inorganic compound and a ceramic powder and/or a metal powder, and in particular to a coating composition suitable for use as a paint and an adhesive for ceramic or metal. Many techniques have been reported in the past for covering the surface of a material with a coating film to protect the inside, but the coating film provided by the composition of the present invention has superior heat resistance compared to those of the prior art. It has the characteristics shown. Examples of coating films with particularly excellent heat resistance obtained by conventional methods include those obtained by coating inorganic pigments such as TiO ₂ , Cr ₂ O ₃ , and Al powder diluted with a solvent. However, their heat resistance was limited to approximately 350°C. The coatings obtained with the compositions of the present invention are stable up to even higher temperatures. In addition, a method has been proposed in the past to obtain a heat-resistant bonded body by bonding objects to be bonded such as metals, ceramics, carbon, etc. Such a heat-resistant bonded body can be used, for example, in discharge lamps, electron tubes, packages, etc. In recent years, the field of application has been further expanded. However, according to the conventionally known method of manufacturing a bonded body, it is difficult to obtain a bonded body with excellent heat resistance, and the manufacturing process is complicated, resulting in high manufacturing costs and, therefore, its use. was limited. As shown in Table 1, typical conventional bonding methods include the Telefunken method, the solder glass method, the active metal method, and the Mo vapor deposition method. Bonding strength using the Telefunken method or Mo vapor deposition method is high, but in these methods, a material other than metal, such as ceramic, is heated in a humidified gas and then metallized with a metal such as Mo (metallization treatment of the surface layer). In addition, it is necessary to go through a complicated process of brazing the target metal using a brazing filler metal, which has the drawback of extremely high manufacturing costs. In addition, the solder glass method uses PbO,
This method involves putting a solder containing Al ₂ O ₃ or CaO as a main component between the ceramic and the metal, and then heat-treating and bonding. However, these solders have a relatively narrow optimum bonding temperature range, so In addition to the need to accurately control the processing temperature to match the objects to be bonded, the bonding performance also changes sensitively depending on the surface condition of the solder, making it difficult to control the quality of the solder itself. In addition, the active metal method uses active metals such as Ti and Zr and Ni, which forms a low melting point alloy with these active metals, such as Ti and Zr.
A relatively simple method of heating Cu, Ag, etc. in a eutectic composition and interposing it between ceramics and ceramics or ceramics and metal in a vacuum or in an inert gas to form a bonded body. However, as shown in Table 1, the joined body obtained by this method has a weak joint strength and extremely poor heat resistance, so the range of use of the obtained joined body is inevitably limited. Ta.

[Table] The present invention overcomes the drawbacks of the conventional methods described above, and can be used as a paint that provides a coating film with excellent heat resistance, or for easily and inexpensively manufacturing a heat-resistant and high-strength joined body. The object of the present invention is to provide a coating composition suitable as an adhesive.
That is, according to the present invention, SiC mainly consists of SiC (amorphous state, β type, α type, or a mixed phase thereof) by heating to a temperature of 400 to 2000°C in a mainly non-oxidizing atmosphere. Semi-inorganic compounds converted into ceramics, ceramic powders and/or
or a metal powder is provided. The composition of the present invention is a coating composition suitable for use as a coating for ceramics or metals, and also for use as an adhesive between two materials of the same or different types selected from ceramics and metals. A suitable adhesive composition. The present invention will be explained in more detail below. Ceramic powder refers to powders of oxides, carbides, silicides, nitrides, borides, carbon graphite, boron, etc., and may be crystalline or amorphous. In addition to commercially available ceramic powders, ceramic powders (mainly
(composed of SiC) can also be used. The particle size of ceramic powder is not particularly important, but it is usually 0.1~
Preferably, it is about 10 microns. The metal powder used as a component of the coating composition of the present invention includes alkaline earth metals, transition metals, typical metals, semimetals, rare earth metals, actinium metals,
It refers to powders of these alloys (containing trace amounts of added elements such as carbon, nitrogen, phosphorus, and boron, which give the alloys various properties). Metal powders may also be crystalline or amorphous. Also, the particle size of the metal powder is not particularly important, but
Usually, it is preferably about 0.1 to 10 microns. The above ceramic powder and metal powder are each separately,
Alternatively, they can be used in combination, so cermets can naturally also be used. In addition to the ceramic powder and/or metal powder described above, the coating composition of the present invention contains, as other components,
Mainly SiC (amorphous state,
It is characterized by containing a semi-inorganic compound (hereinafter sometimes referred to as the specific semi-inorganic compound of the present invention) that can be converted into ceramics consisting of either β-type, α-type, or a mixed phase thereof. The blending ratio of the semi-inorganic compound and the ceramic powder and/or metal powder is expressed as weight % based on the total weight, and the weight % of the semi-inorganic compound is 0.1 to 50 weight %,
The content is preferably 5 to 20% by weight. Examples of the above-mentioned semi-inorganic compounds that can be used in the present invention include linear, cyclic, ladder-like, cage-like, three-dimensional, or mesh-like compounds described in (1) to (4) below. can. (1) Polycarbosilane represented by the following formula (In the above formula, R ₁ to R ₅ are hydrogen and C ₄
The following alkyl groups, _C4 or less haloalkyl groups,
phenyl group, _C5 - _C8 cycloalkyl group, benzyl group or vinyl group; n is 10-10000) (2) Polycarbosiloxane represented by the following formula (In the above formula, R ₁ to R ₇ are hydrogen and C ₄
The following alkyl groups, _C4 or less haloalkyl groups,
phenyl group, _C5 - _C8 cycloalkyl group, benzyl group or vinyl group; n is 10-10000
and the repetition of x units and y units includes both random and block) (3) A polysiloxane compound represented by the following formula (In the above formula, R ₁ to R ₃ are hydrogen and C ₄
The following alkyl groups, _C4 or less haloalkyl groups,
It is a phenyl group, a C ₅ - C ₈ cycloalkyl group, a benzyl group or a vinyl group; n is 1 - 10000; and the repetition of the a unit and b unit includes both random and block. (4) The previous item ( 3) borosiloxane compound and 1 selected from aliphatic polyhydric alcohol, aromatic alcohol, phenols, or aromatic carboxylic acid.
A modified borosiloxane compound obtained by reacting a species or two or more organic compounds at a temperature within the range of 250 to 450°C in an atmosphere inert to the reaction. Regarding the manufacturing method of the semi-inorganic compounds described in (1) to (4) above, the present inventors have previously filed an application for JP-A-51
-126300, Japanese Patent Publication No. 52-74000, Japanese Patent Application Publication No. 52-112700,
Unexamined Japanese Patent Publication No. 53-42300, Unexamined Japanese Patent Application No. 54-61299, Patent Application No. 1983-
127630, disclosed in Japanese Patent Application No. 53-054036. Particularly preferred semi-inorganic compounds for use in the method of the present invention include, for example, the following: can be mentioned. In this case, the terminal group is a hydroxyl group, a methyl group, or a phenyl group. Preferred semi-inorganic compounds for use in the present invention are:
Mainly SiC (amorphous state,
When converted into ceramics consisting of either β type, α type, or a mixed phase thereof, the firing residual rate is particularly high, ranging from 40 to 85%. The specific semi-inorganic compound of the present invention is obtained in liquid form in some cases, so in such cases, ceramic powder and/or
Alternatively, a coating composition can be prepared by adding and mixing metal powder. Therefore, the coating composition of the present invention has
Containing a solvent is not necessarily an essential requirement. However, in order to form a uniform coating,
It is generally preferred to include a solvent. Examples of the solvent used include tetrahydrofuran, benzene, toluene, xylene, hexane, ether, dioxane, chloroform, methylene chloride, petroleum ether, petroleum benzine, ligrosine, chlorofluorocarbon, dimethyl sulfoxide,
Dimethylformamide water etc. can be used alone, but conventional paint thinners (true solvent,
Mixtures of co-solvents and diluting solvents) can also be applied. Furthermore, the coating composition of the present invention may optionally contain a color vehicle, a plasticizer, a drying agent, a pigment, a pigment dispersant, a curing agent, an ultraviolet absorber, an antioxidant, an anti-sagging agent, a leveling agent, etc. , an antifoaming agent, and a crosslinking agent for crosslinking semi-inorganic compounds. The coating composition of the present invention as described above is particularly suitable for coating on ceramic or metal substrates and for use as a paint or adhesive for these substrates. The metal used as the base is preferably a metal or alloy with a melting point of 500°C or higher, and the ceramic base is preferably a metal or alloy with a melting point of 500°C or higher.
Graphite, boron, cement, gypsum, mica, asbestos, etc. are preferred. When used as an adhesive, combinations of metal-metal, metal-ceramics, ceramic-ceramics, ceramic-carbon, carbon-metal, and carbon-carbon can be used as the objects to be joined. When using ceramics or carbon materials, it is particularly effective in constructing irregularly shaped bricks. When the material to be coated and the bonded body are metal, it is preferable to perform sandblasting, alkali treatment, phosphoric acid treatment, or other chemical conversion treatment on the surface after cleaning such as pickling in order to achieve strong coating and bonding. Although the coating method and adhesion method of the present invention can of course be applied to plastics and wood, the effect is more effectively exhibited for the purpose of providing a material that can withstand relatively high-temperature usage conditions. Next, a method for coating (forming a coating film) on a substrate and a method for adhering the substrate using the coating composition of the present invention will be specifically explained. The first coating method is to use powdered semi-inorganic compounds as raw materials (used as they are because they are viscous liquids in the case of low molecular weight materials) and ceramic powder and/or
Alternatively, a solution containing metal powder and optionally additives is applied onto the substrate in a uniform thickness. Although it is not an absolutely necessary condition to use a solvent, it is desirable to use it in order to form a more uniform coating film. As for the application method, general methods such as brushing and spraying can be used. It is preferable to heat the substrate after application. It is preferable to use a non-oxidizing atmosphere (for example, inert gas such as argon, nitrogen, hydrogen gas, CO gas, CO ₂ gas, or vacuum) as the atmosphere during heating, but semi-inorganic compounds may be modified. Organic borosiloxane (air may be used in the case of the compound (4) above). The temperature of heat treatment varies depending on the material of the object to be treated, but generally the heating temperature is in the range of 400°C to 2000°C. As the heating method, various commonly used methods (for example, resistance heating, high frequency heating, infrared heating, acetylene-oxygen burner heating, propane-oxygen burner heating, hydrogen-oxygen burner heating) can be used. At this time, ultraviolet rays and radiation irradiation can be performed in parallel for the purpose of crosslinking the semi-inorganic compounds contained.In the case of solution coating, the coated surface is often stable just by air drying without heating. Heat treatment improves the heat resistance of the coated surface compared to other methods.The next method is adhesion, but it is basically the same as coating.After applying bonding powder or bonding liquid to the bonding surface, heating However, an even stronger bond can be achieved if heating is performed under pressure. Pressure can be applied by simply placing a weight on the top of the object to be joined. In this case, the heating method is a local heating method of only the necessary parts. It is also effective to use a hot press that can heat and pressurize at the same time.So far we have described coating and bonding separately, but it is of course possible to perform both at the same time.In other words, it is possible to perform both at the same time. It is possible to join the bodies and to coat the surface of the joined body at the same time.It is also possible to repeatedly apply and bake the paint.The coated body obtained by the coating composition of the present invention is generally It is characterized by being stable under usage conditions of over 400℃ in air.
When ceramic powder components such as Al ₂ O ₃ and SiO ₂ are used and the baking temperature is restricted to a temperature at which the semi-inorganic compound does not completely transform into an inorganic compound (usually 500°C), the heat-resistant insulating coating becomes can get.
On the other hand, when Al, brass, or the like is used as the metal powder component and the baking temperature is heated to a temperature at which the semi-inorganic compound completely changes to an inorganic compound, a heat-resistant conductive coating film can be obtained. Due to the chemical stability of the paint film after baking, paints mainly made of a combination of ceramic powder and semi-inorganic compounds are susceptible to acids, alkalis, _SO2 and other corrosive gases, waste gases, reducing gases, molten metals, and molten metals. Demonstrates high corrosion resistance against slag, etc. Also, generally speaking, the coating film adheres strongly to the substrate, and no peeling is observed under normal quenching conditions. Next, the bonded product provided by the present invention is also generally stable under usage conditions of 400° C. or higher in air. The bonding strength is over 700Kg/cm ² and does not decrease even at 500°C. The electrical conductivity and chemical stability of the bonding surface are similar to the combination of paint and processing temperature in the case of a paint film. The joint surface is stable even under rapid cooling conditions. The material of the present invention is mainly applied to the following applications. (1) Building materials - panels, domes, mobile homes, walls, ceiling materials, flooring materials, cooling towers,
Septic tanks, sewage tanks, water supply tanks, hot water supply piping, drainage pipes, heat conversion heat pipes, etc. (2) Equipment materials for aircraft and space development - fuselages, wings, helicopter drive shafts, jet engine compressors, rotors, stators , blades, complex casings, housings, nose cones, rocket nozzles, brake materials, tire cords, etc. (3) Marine materials - boats, yachts, fishing boats, work boats, etc. (4) Road transportation equipment materials - the previous section of vehicles parts, side panels, water tanks, toilet units, seats, car bodies, containers, road equipment, guardrails, valets, tanks for tank trucks, cars, motorcycles, etc. (5) Corrosion-resistant equipment materials - tanks, tower ducts, staff, etc. Pipes, etc. (6) Electrical materials - surface heating elements, varistors, igniters,
Thermocouples, etc. (7) Sports equipment - boats, bows, skis, snowmobiles, water skis, glider bodies, tennis rackets, golf shafts, helmets, butts, racing jackets, etc. (8) Mechanical elements - gaskets, gaskets, gears, brake materials, Friction materials, abrasive materials, etc. (9) Medical equipment materials - prosthetic legs, prosthetic limbs, etc. (10) Audio equipment materials - cantilevers, tone arms. Speaker cones, voice coils (11) Nuclear power materials (B ₄ C coating, dispersion) Neutron absorbing materials, neutron reflecting materials, fuel cladding end cap seals (12) Electronic equipment parts Plain wiring, component bonding (room temperature, heating) ( 13) Vacuum component manufacturing The present invention will be explained below using examples. Example 1 310 g of boric acid and 1898 diphenyldichlorosilane
g was placed in a three-necked flask (No. 5) together with 3 n-butyl ether, and reacted at 100° C. with stirring for 18 hours. After cooling, a white precipitate was obtained. After removing n-butyl ether, the precipitate was washed with methanol to remove unreacted boric acid, and then washed with water to obtain 1680 g of a borodiphenylsiloxane compound. 200 g of this borodiphenylsiloxane compound was homogeneously mixed with 20 g of hydroquinone, and the mixture was placed in a 500 ml flask for 1 hour in a nitrogen atmosphere with stirring.
The mixture was heated at a temperature increase rate of 300°C and reacted for 1 hour to obtain a pale yellow semi-inorganic compound. 1 part by weight of the above semi-inorganic compound was added to 7 parts by weight of gel-like silica with a particle size of 0.5μ, and 1 part by weight of an additive obtained by modifying a silicone resin with an alkyd resin and 1 part by weight of a tetrahydrofuran solvent were added to the whole mixture. It was made into an emulsion-like paint. This material was applied to a Parkerized mild steel plate or copper plate and heated in air to 500°C, resulting in a good heat-resistant insulating coating. This coating maintains its insulation properties safely even when used in air at 500℃. Almost the same results were obtained even when the gelled silica was replaced with γ-alumina, titanium oxide, zinc white, chromium oxide, red iron oxide or partially replaced. The paint of this example is also effective for stabilizing coating and impregnating carbonaceous materials. The coating film containing the above-mentioned gel-like silica was further heated at 600°C.
Even when heated for 1 hour at 700°C and 800°C, the coating film does not peel off and has sufficient electrical insulation properties. or
Even when a sample heated to 800℃ is suddenly immersed in water at room temperature, it does not peel off and remains adhered to the metal plate. Typical properties of the paint obtained in this way are: usage temperature limit 1000℃, adhesive strength (shear) 25Kg/cm ² , and pencil hardness.
3H, specific electrical resistance of 10 ¹⁴ Ω・cm, and optimal film thickness of 50 μm or less. In addition, electric wires and wires coated with this paint at a thickness of 30 μm on Ni-plated copper conductors with a diameter of 1 mm and
When baking is performed at 300℃, 400℃, 500℃, and 600℃, the mandrel diameters that can be wrapped are 3, 3, and 3, respectively.
It was found that the towability of the 5, 12, and 12 times diameter was extremely excellent. Example 2 1 part by weight of the semi-inorganic compound used in Example 1 was added to 7 parts by weight of metallic aluminum powder with a particle size of 2μ, and 1 part by weight of the same additive as used in Example 1 was added.
parts by weight and 1 part by weight of a solvent were added to prepare an emulsion-like paint. This product was applied to a polished steel plate and an alkali-treated mild steel plate, and then heated in air to 500°C. As a result, a good heat-resistant coating film was obtained. This coating is stable in air up to 800℃ and stable for regular use at 650℃. Almost the same results were obtained when aluminum powder was replaced with brass powder or copper powder, or when a part of the aluminum powder was replaced. Example 3 Anhydrous xylene 2 and 300 g of metallic sodium were placed in the three-necked flask of No. 5, heated to the boiling point of xylene (136° C.) under a nitrogen gas stream, and 540 g of dimethyldichlorosilane was added dropwise from the dropping funnel of No. 1 over 30 minutes. After the dropwise addition was completed, heating was continued for 18 hours to produce a blue-purple precipitate. This precipitate was filtered and washed first with methanol and then with water to remove white powder poly(dimethylsilane) at 215%
I got g. 3.5 wt% of the borodiphenylsiloxane compound synthesized in Example 1 was added to 100 g of this poly(dimethylsilane), and the mixture was heated at 350°C under a nitrogen gas stream for 10 min.
After a period of reaction, 66 g of polycarbosiloxane was obtained. 4 parts by weight of this semi-inorganic compound, 4 parts by weight of α-SiC powder with a particle size of 2μ, 1 part by weight of silicone resin,
1 part by weight of n-hexane was added and mixed to form a paint. Apply this material to the entire surface of the graphite plate, and add _N2
Heated to 1500°C in a stream of air. thus obtained
SiC coated graphite and untreated graphite each in air for 10
As a result of heating at 500°C for an hour, the oxidation loss of the coated product was approximately 1/30 of that of the untreated product. Furthermore, almost no reaction to molten Al occurred in the coated product. In addition, after applying this paint to a commercially available SiC crucible for metal melting and repeating the same heat treatment twice, it was filled with converter slag and heated at 1600°C. As a result, the time required for the molten material to seep out of the crucible has increased approximately 10 times. Example 4 100g of poly(dimethylsilane) obtained in Example 3
was pyrolyzed and condensed at 400℃ in a _N2 stream for 10 hours, and 35g
of polycarbosilane was obtained. _A powder (particle size:
0.5 μ), 4 parts by weight of the semi-inorganic compound used in Example 1 and 1 part by weight of Ni powder with a particle size of 1 μ are mixed therein, and 1 part by weight of tetrahydrofuran is added to form a paste. It was used as an adhesive. After applying this material to the surface of Nb metal and alumina to be bonded, we heated it to 1700℃ in a _N2 stream.
A bond with a tensile strength of 7.7 Kg/mm ² was achieved. This adhesive surface was particularly resistant to thermal shock. Example 5 4 parts by weight of the semi-inorganic polymer used in Example 1,
4 parts by weight of α-SiC having a particle size of 1 μm were mixed, and 1 part by weight of tetrahydrofuran was added to the mixture to obtain a paste adhesive. Two commercially available SiC plates (density 3.0 g/cm ³ ) were prepared, and the above paste was applied to both surfaces to be bonded, and then the plates were stacked together. Adhesion was achieved by heating the bonded area with an acetylene burner, and as a result, an adhesion with a tensile strength of 3.0 Kg/mm ² was achieved. This adhesive surface was found to be resistant to thermal shock as a result of a drop test in water from a temperature of 800°C. This adhesive can be used, for example, to bond objects with complex shapes such as irregularly shaped bricks, and different objects to be bonded such as SiC--C, C--MgO, and the like.

Claims (1)

[Claims] 1. Ceramic mainly composed of SiC (amorphous state, β type, α type, or a mixed phase thereof) by heating to a temperature of 400 to 2000°C in a mainly non-oxidizing atmosphere. A linear, cyclic, ladder-like, cage-like, three-dimensional or network-like polycarbosilane that is converted into (1) a polycarbosilane represented by the following formula: (In the above formula, R ₁ to R ₅ are hydrogen and C ₄
The following alkyl groups, _C4 or less haloalkyl groups,
phenyl group, _C5 - _C8 cycloalkyl group, benzyl group or vinyl group; n is 10-10000
) (2) Polycarbosiloxane represented by the following formula (In the above formula, R ₁ to R ₇ are hydrogen and C ₄
The following alkyl groups, _C4 or less haloalkyl groups,
phenyl group, _C5 - _C8 cycloalkyl group, benzyl group or vinyl group; n is 10-10000
(and the repetition of x units and y units includes both random and block) (3) A borosiloxane compound represented by the following formula (In the above formula, R ₁ to R ₃ are hydrogen and C ₄
The following alkyl groups, _C4 or less haloalkyl groups,
a phenyl group, a _C5 - _C8 cycloalkyl group, a benzyl group, or a vinyl group; n is 1 to 10,000; and the repetition of the a unit and b unit includes both random and block) and (4) the preceding item. (3) borosiloxane compound and 1 selected from aliphatic polyhydric alcohols, aromatic alcohols, phenols, or aromatic carboxylic acids.
A modified borosiloxane compound obtained by reacting a species or two or more organic compounds in an oppositely inert atmosphere at a temperature within the range of 250 to 450°C, a semi-inorganic compound selected from: A coating composition comprising at least one of the following, and a ceramic powder and/or a metal powder. 2. The composition according to claim 1 for use as a coating for ceramic or metal. 3. The composition according to claim 1 for use as an adhesive between two materials of the same or different types selected from ceramics and metals.