Film-forming auxiliary agent, film-forming coating liquid, laminate, and film-forming method

Abstract

To provide a film-forming auxiliary capable of forming a silica-containing alumina film having good mechanical strength and excellent in adhesion and wear resistance even after a heat resistance test by a chemical vapor deposition method.SOLUTION: A compound represented by the general formula (1): wherein R1 and R2 are each independently a hydrogen atom, a hydrocarbon group having 1 to 18 carbon atoms, an amino group, a hydroxyl group, or an alkoxy group having 1 to 3 carbon atoms, and R1 and R2 may be bonded to each other to form a heterocyclic ring. The film-forming auxiliary agent according to claim 1, wherein: SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a film-forming auxiliary, a film-forming coating liquid, a laminate, and a film-forming method. [Background technology]

[0002] Silica-containing alumina has properties such as low thermal expansion, thermal shock resistance, and corrosion resistance. A metal oxide that has been used for a long time is called mullite, and is used in high-temperature structural materials, refractories such as engineering ceramics, and in the ceramics industry.

[0003] Known methods for forming ceramics include die molding, cold isostatic pressing, extrusion, injection molding, and slip casting. These methods allow for the rapid production of complex-shaped products at low cost, and because the molds can be reused, mass production is possible. However, when manufacturing ceramics, raw material powders or a slurry made by adding a solvent such as water to the raw material powders to form a mud-like substance is poured into a mold and then fired and sintered, which causes problems such as expansion and contraction, leading to problems with interlocking and voids. Furthermore, these problems occur even when using silica-containing alumina, which has a low thermal expansion coefficient, making it difficult to form products with good dimensional accuracy.

[0004] Furthermore, a method for forming a silica-containing alumina film is known, for example, as disclosed in Patent Document 1, which employs plasma spraying to form a film with a thickness of approximately 10 μm to 200 μm. The plasma spraying method has the drawback that the low-specific-gravity spray material used to achieve a film thickness of approximately 10 μm or less is difficult to feed and inject.

[0005] Furthermore, mist chemical vapor deposition (hereinafter also referred to as "mCVD") is known as a method capable of depositing dense films with a thickness of 10 μm or less, in which a solution containing metal atoms is converted into a mist consisting of droplets with a particle size of 500 μm or less by ultrasound or the like, and then reacted on a substrate heated to 500°C or less to form a metal oxide (Patent Document 2). mCVD is a film-deposition method using chemical vapor deposition, which involves reactions in the gas phase of raw materials and chemical reactions on the substrate, and is suitable for mass production because it does not require a high vacuum. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2019-11238 [Patent Document 2] Japanese Patent Application Publication No. 2018-140352 Summary of the Invention [Problem to be solved by the invention]

[0007] As mentioned above, it is difficult to form products with good dimensional accuracy when forming ceramics using methods such as mold forming. However, the inventors thought that by forming a material with high dimensional stability in advance and coating it with silica-containing alumina, it would be possible to maintain high dimensional stability and manufacture castings with low thermal expansion coefficient, thermal shock resistance, and corrosion resistance.

[0008] On the other hand, when a silica-containing alumina film is formed by chemical vapor deposition, hydration water may remain in the film, and this water is gradually released during film formation or when used in a high-temperature environment, resulting in problems such as a decrease in adhesion of the film to the substrate and a decrease in mechanical strength. As a result, the low thermal expansion coefficient, thermal shock resistance, and corrosion resistance originally expected of silica-containing alumina cannot be exhibited, and there is a risk of the substrate corroding from the damaged areas of the film.

[0009] In view of the above problems, the present invention aims to provide a film-forming aid that can form a silica-containing alumina film by chemical vapor deposition, which has good mechanical strength and excellent adhesion and abrasion resistance even after heat resistance testing.

[0010] Another object of the present invention is to provide a film-forming coating fluid containing the above-mentioned film-forming aid, a laminate having a silica-containing alumina film formed from the film-forming coating fluid, and a method for forming a silica-containing alumina film by chemical vapor deposition. [Means for solving the problem]

[0011] The present invention relates to a compound represented by the general formula (1): [ka] (R in the formula 1 and R 2 are each independently a hydrogen atom, a hydrocarbon group having 1 to 18 carbon atoms, an amino group, a hydroxyl group, or an alkoxy group having 1 to 3 carbon atoms, and R 1 and R 2 may be bonded to each other to form a heterocycle.

[0012] The present invention also relates to [2] a film-forming coating liquid that preferably contains the film-forming auxiliary of [1] above and a solvent.

[0013] The present invention also relates to the film-forming coating fluid according to the above item [2], which preferably contains [3] a silicon-containing compound and an aluminum-containing compound.

[0014] The present invention also relates to [4] the film-forming coating fluid according to the above [3], wherein the molar ratio of aluminum atoms of the aluminum-containing compound to silicon atoms of the silicon-containing compound (moles Al / moles Si) is preferably 0.01 to 20, and the molar ratio of the compound to the sum of the silicon atoms and the aluminum atoms (moles of the compound / (moles Al+moles Si)) is preferably 1 to 100.

[0015] The present invention also relates to [5] the film-forming coating fluid according to the above [3] or [4], wherein the silicon-containing compound is preferably an alkoxysilane having 4 to 20 carbon atoms.

[0016] The present invention also relates to [6] a laminate having a silica-containing alumina film formed on the surface of a substrate from any one of the film-forming coating solutions [2] to [5] above, the film having a thickness of 10 μm or less.

[0017] The present invention also relates to [7] the laminate according to the above [6], wherein the silica-containing alumina film preferably has a composition formula: SiaAlbOcTd (wherein Si is a silicon atom, Al is an aluminum atom, O is an oxygen atom, and T is one or more atoms other than Si, Al, and O, a, b, c, and d are weight ratios, a+b+c+d=100, a is 3 or more and 45 or less, b is 3 or more and 50 or less, c is 35 or more and 70 or less, and d is 0 or more and 40 or less).

[0018] The present invention also relates to [8] a method for forming a silica-containing alumina film by chemical vapor deposition, comprising: a step of misting the film-forming coating liquid according to any one of [3] to [5] above; and a step of supplying the mist obtained to a heated substrate surface and causing a reaction on the substrate.

[0019] The present invention also relates to [9] a method for forming a silica-containing alumina film by chemical vapor deposition, comprising a two-tank mist-forming step of separately misting the film-forming coating solution according to [2] above and a metal source solution containing a silicon-containing compound and an aluminum-containing compound, and a step of supplying each mist to a heated substrate surface and causing a reaction on the substrate.

[0020] The present invention also relates to the method for forming a silica-containing alumina film by chemical vapor deposition according to the above item [9], wherein the molar ratio of the compound to the sum of silicon atoms of the silicon-containing compound and aluminum atoms of the aluminum-containing compound (moles of the compound / (moles of Al+moles of Si)) is preferably 1 to 100. [Effects of the Invention]

[0021] The film-forming aid of the present invention is presumed to have the effect of removing hydration water in a silica-containing alumina film, which is a cause of a decrease in mechanical strength when the film is formed by chemical vapor deposition. Therefore, a silica-containing alumina film formed from a film-forming coating liquid containing the film-forming aid has good mechanical strength and is excellent in adhesion and abrasion resistance even after a heat resistance test. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a schematic diagram of a film-forming apparatus for a silica-containing alumina film in a method for producing a silica-containing alumina film according to one embodiment of the present invention. [Figure 2] 1 is a schematic diagram of a film-forming apparatus for a silica-containing alumina film in a method for producing a silica-containing alumina film according to one embodiment of the present invention. [Figure 3] 1 is a schematic diagram of a mist generator in a film forming apparatus for forming a silica-containing alumina film in a method for producing a silica-containing alumina film according to one embodiment of the present invention. [Figure 4] 1 is a schematic diagram of a mixing tank in a film forming apparatus for a silica-containing alumina film in a method for producing a silica-containing alumina film according to one embodiment of the present invention. [Figure 5] 1 is a schematic diagram of a film forming section in a film forming apparatus for forming a silica-containing alumina film in a method for producing a silica-containing alumina film according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0023] Hereinafter, a film-forming auxiliary, a film-forming coating liquid, a laminate, and a film-forming method according to one embodiment of the present invention will be described with reference to drawings as necessary.

[0024] <Film-forming aid> The film-forming aid of the present invention is used for forming a silica-containing alumina film by chemical vapor deposition and is represented by the general formula (1): [ka] (R in the formula 1 and R 2 are each independently a hydrogen atom, a hydrocarbon group having 1 to 18 carbon atoms, an amino group, a hydroxyl group, or an alkoxy group having 1 to 3 carbon atoms, and R 1 and R 2 may be bonded to each other to form a heterocycle.

[0025] The compound represented by the general formula (1) acts as a weakly basic catalyst, promoting the hydrolysis of silicon-containing compounds to generate silanols. It is believed that the water of hydration remaining in the silica-containing alumina film is consumed in the hydrolysis reaction, resulting in a highly heat-resistant silica-containing alumina film. Furthermore, the compound represented by the general formula (1) may enhance nucleophilicity by abstracting protons from the hydroxyl groups of the silanols, promoting the formation of silicon-oxygen-aluminum bonds through the reaction with highly electrophilic aluminum. The promotion of the reaction reduces the amount of unreacted precursor remaining in the silica-containing alumina film, thereby suppressing a decrease in mechanical strength. Furthermore, the compound represented by the general formula (1) has excellent reactivity among weakly basic catalysts and is less likely to remain in the silica-containing alumina film.

[0026] In the compound represented by the general formula (1), in terms of the mechanical strength of the silica-containing alumina film, the adhesion after a heat resistance test, the wear resistance after a heat resistance test, and the surface roughness after a heat resistance test, R 1 and R 2 are each independently a hydrogen atom, an amino group, a hydroxyl group, or an alkoxy group having 1 to 3 carbon atoms, or R 1 and R 2 In the heterocyclic ring formed by bonding together, it is preferable that the heterocyclic ring has 4 to 8 carbon atoms including the functional group bonded to the heterocyclic ring. 1 and R 2 are each more preferably independently a hydrogen atom.

[0027] <Film-forming coating liquid> The film-forming coating fluid of the present invention is preferably in the form of a coating fluid (A) containing the film-forming aid and a solvent, or a coating fluid (B) containing the film-forming aid, a silicon-containing compound, an aluminum-containing compound, and a solvent. The coating fluid (A) is suitable for a chemical vapor deposition film-forming method in which the coating fluid and a metal source solution containing a silicon-containing compound and an aluminum-containing compound are separately misted and the respective mist is supplied to form a silica-containing alumina film. The coating fluid (B) is also suitable for a chemical vapor deposition film-forming method in which the coating fluid is misted and the resulting mist is supplied to form a silica-containing alumina film. The mist-forming method used in the present invention includes atomization, dropletization, and the like, and refers to breaking down a liquid into fine particles and dispersing them in a gas.

[0028] <Solvent> The solvent may be any solvent capable of dissolving the compound represented by general formula (1). From the viewpoint of mist generation efficiency, however, a solvent having a boiling point of 40°C to 150°C and a viscosity at 25°C of 1.3 mPa·sec or less is preferred, a solvent having a viscosity of 0.1 mPa·sec to 1.0 mPa·sec or less is more preferred, and a solvent having a viscosity of 0.5 mPa·sec to 1.0 mPa·sec or less is even more preferred. Examples of the solvent include polar solvents such as lower alcohols (e.g., methanol), nitrile-based solvents (e.g., acetonitrile), and water, as well as nonpolar solvents (e.g., toluene). Two or more of these solvents may be mixed. Among these solvents, polar solvents are preferred, and lower alcohols and water are more preferred because they act as an oxidation source to fully achieve the effects of the present invention. Furthermore, the inclusion of water is preferred because of ease of handling and the ability to prevent ignition of the misted coating liquid. Here, the oxygen source refers to a source of oxygen atoms for converting the silicon-containing compound and aluminum-containing compound described below into metal oxides.

[0029] <Silicon-containing compounds> The silicon-containing compound may be any compound that can be misted, and examples thereof include silane, siloxane, silazane, polysilazane, and alkoxysilane. Among these, alkoxysilane is preferred from the viewpoints of reactivity and the mechanical strength and heat resistance of the resulting silica-containing alumina film. From the viewpoint of reactivity, alkoxysilanes having 4 to 20 carbon atoms are more preferred.

[0030] <Aluminum-containing compounds> The aluminum-containing compound may be any compound that can be turned into a mist, such as an alkoxide compound, a β-diketone compound, an organic acid salt compound, or an inorganic salt compound. Among these, from the viewpoint of reactivity, an alkoxide compound or a β-diketone compound is preferred.

[0031] In the film-forming coating liquid, the compound represented by the general formula (1) is preferably contained in an amount of from 0.01% to 40% by weight, more preferably from 0.1% to 20% by weight.

[0032] In the coating liquid (A) and the metal source solution, or the coating liquid (B), the molar ratio of the film-forming aid to the total of silicon atoms and aluminum atoms (moles of the compound / (moles of Al+moles of Si)) is preferably 1 to 100, more preferably 5 to 80, from the viewpoint of the mechanical strength and heat resistance of the silica-containing alumina film; more preferably 10 to 70, from the viewpoint of the surface roughness of the silica-containing alumina film; and even more preferably 20 to 60, from the viewpoint of the adhesion of the silica-containing alumina film.

[0033] In the coating liquid (B) or the metal source solution, the molar ratio of aluminum atoms of the aluminum-containing compound to silicon atoms of the silicon-containing compound (moles Al / moles Si) is preferably 0.01 to 20, more preferably 0.1 to 10 from the viewpoint of the mechanical strength and heat resistance of the silica-containing alumina film, even more preferably 0.2 to 6 from the viewpoint of the adhesion of the silica-containing alumina film, and even more preferably 0.2 to 2 from the viewpoint of the abrasion resistance of the silica-containing alumina film.

[0034] <Laminate> The laminate of the present invention has a silica-containing alumina film formed on the surface of a substrate from the film-forming coating liquid and having a thickness of 10 μm or less. The laminate is preferably formed by directly laminating the silica-containing alumina film onto a sheet-like substrate having a thickness of 0.2 mm to 20 mm, or onto a substrate processed into a specific shape using a mold. The term "direct lamination" as used herein means that there is no layer of 100 nm or more between the silica-containing alumina film and the substrate.

[0035] Examples of the material for the substrate include metal materials such as copper or copper alloy, aluminum or aluminum alloy, zinc, and silicon, and inorganic solid materials such as oxides, carbides, nitrides, and borides.

[0036] The silica-containing alumina film preferably has a composition formula: SiaAlbOcTd (wherein Si is a silicon atom, Al is an aluminum atom, O is an oxygen atom, and T is one or more atoms other than Si, Al, and O; a, b, c, and d are weight ratios, where a+b+c+d=100, a is 3 or more and 45 or less, b is 3 or more and 50 or less, c is 35 or more and 70 or less, and d is 0 or more and 40 or less). From the viewpoint of mechanical strength, the silica-containing alumina film more preferably has a value of a is 3 or more and 40 or less, b is 3 or more and 40 or less, c is 50 or more and 63 or less, and d is 0 or more and 30 or less. The above composition ratios can be determined by dynamic SIMS.

[0037] In the composition formula, T is an optional component and may not be included, or may contain a carbon atom from the viewpoint of preventing the silica-containing alumina film from hardening and suppressing cracks.

[0038] <Method for forming silica-containing alumina film by chemical vapor deposition> The method for forming the silica-containing alumina film may be any chemical vapor deposition method, and mCVD is preferred from the viewpoint of excellent film formation speed and film formation uniformity.

[0039] Examples of mCVD include a method for forming a silica-containing alumina film by chemical vapor deposition, which includes a two-tank mist-forming step in which the above-mentioned film-forming coating solution (A) and a metal source solution containing a silicon-containing compound and an aluminum-containing compound are separately misted, and a step in which each mist is supplied to a heated substrate surface and reacted on the substrate; and a method for forming a silica-containing alumina film by chemical vapor deposition, which includes a mist-forming step in which the above-mentioned film-forming coating solution (B) is misted, and a step in which the obtained mist is supplied to a heated substrate surface and reacted on the substrate.

[0040] 1 shows a schematic diagram of a film-forming apparatus (1) in a method for forming a silica-containing alumina film, which has a two-tank mist-forming process in which the above-mentioned film-forming coating solution (A) and a metal source solution containing a silicon-containing compound and an aluminum-containing compound are separately misted. The film-forming apparatus (1) is composed of two mist-forming devices, a mixing tank, and a film-forming machine (film-forming section) connected by piping.

[0041] 2 shows a schematic diagram of a film-forming apparatus (2) in a method for forming a silica-containing alumina film, which includes a mist-forming step of misting the film-forming coating solution (B). The film-forming apparatus (2) is composed of one mist-forming device and a film-forming machine (film-forming section) connected by piping.

[0042] Figure 3 shows a schematic diagram of the mist generator in a silica-containing alumina film deposition system. The mist generator consists of a container for containing raw materials and an ultrasonic generator equipped with an ultrasonic vibrator. The container is a glass cylinder with a Teflon (registered trademark) lid and a bottom made of polyethylene or tetrafluoroethylene-hexafluoropropylene copolymer film. Two glass pipes are installed to pass through the lid. The first pipe is installed to deliver carrier gas (nitrogen) for transporting the mist into the container, and the second pipe is installed to deliver the mist generated in the container and carrier gas to the deposition machine. The container is placed in an ultrasonic generator together with water, and ultrasonic waves generated by the ultrasonic vibrator are transmitted to the raw materials via the water and the polyethylene film, etc., to turn the raw materials into mist.

[0043] FIG. 4 shows a schematic diagram of a mixing tank in a silica-containing alumina film forming apparatus. The mixing tank is a glass container equipped with a Teflon (registered trademark) lid. Three glass pipes are provided to pass through the lid. Of the three pipes, two are connected to two mist generators, and the central pipe is connected to the film forming unit via a pipe. The mist generated in the mist generator is transported to the film forming unit via the mixing tank. This mixing tank is mainly used to mix the mists generated in the separate mist generators.

[0044] Figure 5 shows a schematic diagram of the film formation section of a silica-containing alumina film formation apparatus. The film formation section consists of a metal jig connected to the mist generator or mixing tank and a hot plate. The jig is connected to the mist generator or mixing tank with a silicone tube and is provided to heat the mist and the substrate. As the heated mist passes over the substrate, a chemical reaction occurs on the substrate to form a silica-containing alumina film. Furthermore, if a jig with a large internal space is used in Figure 5, it is possible to form a film not only on plate-shaped substrates but also on substrates with three-dimensional shapes. The hot plate mentioned above is provided to heat the jig.

[0045] In the mCVD, an oxidizing agent such as ozone, oxygen, or hydrogen peroxide may be used as the oxygen source, with ozone being more preferred. Furthermore, to prevent the mist coating liquid from igniting, water, alcohol, or the like may be used as the oxygen source. Here, the oxygen source refers to a source of oxygen atoms for converting aluminum complexes or salts and silicon compounds into metal oxides.

[0046] The carrier gas is preferably an inert gas containing no more than 10,000 ppm (volume ratio) of oxygen in order to suppress oxidation of the substrate surface.

[0047] In mCVD, a silica-containing alumina film is preferably formed by thermally reacting a mist of raw material on a substrate in an atmosphere at a temperature of 200°C to 500°C, more preferably at 300°C to 450°C. [Example]

[0048] The present invention will be described in more detail below with reference to examples and comparative examples.

[0049] <Examples 1 to 29> <Preparation of coating solution for film formation> Using the raw materials and blending amounts shown in Tables 1 to 6, film-forming coating solutions were prepared. <Formation of silica-containing alumina film on substrate> Using the film-forming apparatus (mist CVD apparatus) shown in Figures 2, 3, and 5, a silica-containing alumina film was formed on a substrate using the following method. A polyethylene or tetrafluoroethylene-hexafluoroethylene copolymer film was fixed 1 cm from the bottom of a glass cylinder (13 cm diameter, 15 cm height) with an O-ring and caulking agent. A Teflon® lid was attached to the top of the cylinder, and two holes were drilled in the lid to insert glass pipes for nitrogen gas supply and mist transport. The glass tube with a branch pipe for mist transport was placed 1–2 cm from the metal material on the hot plate. The branch pipe was connected to an ozone generator via Teflon® tubing to allow the introduction of ozone-oxygen gas. The cylinder was immersed in a water bath, and an ultrasonic vibrator (ultrasonic atomization unit HMC-2401; Honda Electronics Co., Ltd.) was placed directly below the polyethylene or tetrafluoroethylene-hexafluoropropylene. The hot plate was placed in a nitrogen-filled box, and film formation began once the oxygen concentration reached 1% or less. The above-mentioned film-forming coating solution was placed in a cylinder, and the ultrasonic transducer was activated. Ultrasonic waves were transmitted to the film-forming coating solution via the water in the tank and polyethylene or tetrafluoroethylene-hexafluoropropylene copolymer, atomizing a portion of the coating solution. The misted film-forming coating solution was then transported onto a substrate (30 mm x 30 mm) using nitrogen gas. The substrate was heated to 360 °C using a hot plate. Once the misted film-forming coating solution reached the substrate, a chemical reaction occurred, forming a silica-containing alumina film and yielding a laminate. The thickness of the silica-containing alumina film was adjusted by the film-forming time (the time the misted film-forming coating solution was sprayed onto the substrate) and measured using the following method. The nitrogen gas flow rate was 11 L / min, the ozone concentration in the ozone-oxygen gas was 5000 ppm, the ozone-oxygen gas flow rate was 1 L / min, the ultrasonic vibrator frequency was 2.4 MHz, the voltage was 24 V, and the current was 0.6 A.

[0050] Example 30 <Preparation of coating solution for film formation> Example 30 was a two-tank system, and a film-forming coating solution was prepared using the raw materials and blending amounts shown in Table 3, including a coating solution containing a film-forming aid and a solvent, and a metal source solution containing a silicon-containing compound, an aluminum-containing compound, and a solvent. <Formation of silica-containing alumina film on substrate> Using the film-forming apparatus (mist CVD apparatus) shown in Figures 1, 3, and 5, a silica-containing alumina film was formed on a substrate using the following method. A polyethylene or tetrafluoroethylene-hexafluoroethylene copolymer film was fixed 1 cm from the bottom of a glass cylinder (13 cm diameter, 15 cm height) with an O-ring and caulking agent. A Teflon® lid was attached to the top of the cylinder, and two holes were drilled in the lid into which glass pipes for nitrogen gas supply and mist transport were inserted. The cylinder was immersed in a water bath, and an ultrasonic vibrator (HMC-2401 ultrasonic atomization unit; Honda Electronics Co., Ltd.) was placed directly below the polyethylene or tetrafluoroethylene-hexafluoropropylene. The hot plate was placed in a box filled with nitrogen, and film formation began once the oxygen concentration reached 1% or less. The above-mentioned coating solution and metal source solution were placed separately in two cylinders, and an ultrasonic transducer was activated. Ultrasonic waves were transmitted to the coating solution and metal source solution via the water in the tank and polyethylene or tetrafluoroethylene-hexafluoropropylene copolymer, atomizing a portion of the solution. The misted coating solution was then transported onto a substrate (30 mm x 30 mm) using nitrogen gas. The substrate was heated to 360 °C on a hot plate. Once the misted coating solution and metal source solution reached the substrate, a chemical reaction occurred, forming a silica-containing alumina film and obtaining a laminate. The thickness of the silica-containing alumina film was adjusted by the deposition time (the time the misted coating solution and metal source solution were sprayed onto the substrate) and measured using the following method. The nitrogen gas flow rate was 11 L / min, the ultrasonic transducer frequency was 2.4 MHz, the voltage was 24 V, and the current was 0.6 A.

[0051] <Comparative Example 1> <Preparation of coating solution for film formation> A film-forming coating solution was prepared using the raw materials and blending amounts shown in Table 4. <Formation of silica-containing alumina film on substrate> A silica-containing alumina film was formed in the same manner as in Examples 1 to 29.

[0052] <Comparative Example 2> <Preparation of coating solution for film formation> A film-forming coating solution was prepared using the raw materials and blending amounts shown in Table 4. <Formation of silica-containing alumina film on substrate> A coating solution was obtained by adding water to the film-forming coating solution prepared with the composition shown in Table 4 and stirring at room temperature. This coating solution was used to apply the coating solution to a substrate, and then heated on a hot plate heated to 360°C to obtain a silica-containing alumina film.

[0053] The samples obtained above were evaluated as follows, and the results are shown in Tables 1-4.

[0054] <Measurement of thickness of silica-containing alumina film> The thickness of the silica-containing alumina film was measured by forming a silica-containing alumina film on a 3 cm square silicon wafer as the substrate and measuring the thickness with a surface profiler (DektakXT-S, manufactured by Bruker Japan Co., Ltd.) The difference between a spot 3.5 mm from the edge of the obtained laminate and the substrate was measured, and the average of the 10 spots on both ends was measured as the film thickness.

[0055] <Measurement of the composition of silica-containing alumina film> Dynamic SIMS (PHI ADEPT: manufactured by Ulvac-PHI) was used to calculate the weights and ratios of aluminum, silicon, oxygen, and carbon atoms per unit volume. The dynamic SIMS conditions were as follows: primary ion species: Cs+, primary acceleration voltage: 5.0 kV, detection area: 45 × 45 μm. The sample was prepared using a copper substrate with a 1 μm silica-containing alumina film. Measurements were taken from the center of the sample in the depth direction, and the depth at which silicon was detected was defined as 1 μm. The weight ratios of the four atoms were calculated from the secondary ion intensities, relative sensitivity coefficients, and atomic weights of aluminum, silicon, oxygen, and carbon atoms. Since the sum of the four atomic weights per unit volume did not differ by more than 1% from the specific gravity of the metal oxide film, the metal oxide film was assumed to be primarily composed of these four atoms, and the weight ratios of the four atoms per unit volume were calculated as the composition ratio.

[0056] <Mechanical strength evaluation> A 3 cm square copper substrate was used as the substrate, and the resulting laminate was wrapped around mandrels with diameters of 20 mm, 25 mm, and 32 mm based on a bending resistance test (cylindrical mandrel method) in accordance with JIS K5600-5-1:1999. The laminate was then visually inspected for cracks in the silica-containing alumina film and evaluated. The evaluation criteria are shown below. "Evaluation A," "Evaluation B," and "Evaluation C" are acceptable, while "Evaluation D" is unacceptable. Evaluation A: No cracks were observed when a mandrel with a diameter of 20 mm was used. Rating B: Cracks were observed when a mandrel with a diameter of 20 mm was used, but no cracks were observed when a mandrel with a diameter of 25 mm was used. C: Cracks were observed when a mandrel with a diameter of 25 mm was used, but no cracks were observed when a mandrel with a diameter of 32 mm was used. Rating D: Cracks were observed on the 32 mm diameter mandrel.

[0057] <Evaluation of adhesion after heat resistance test> A 3cm square Si wafer was used as the substrate, and the resulting laminate was subjected to a heat resistance test at 400°C for 24 hours, after which it was evaluated according to the test method specified in JIS K5600-5-6:1999 (cross-cut method). After the heat resistance test, the laminate was cut into a grid using a special tool, and adhesion was evaluated using 25mm wide transparent pressure-sensitive adhesive tape. The evaluation criteria are shown below. Note that "Evaluation A," "Evaluation B," "Evaluation C," and "Evaluation D" are considered passing, and "Evaluation E" is a failing grade. Rating A: The edges of the cut are completely smooth and there is no peeling on any of the grids. Grade B: The percentage of peeled lattices in the cross-cut area is less than 5%. Rating C: In the cross-cut area, the percentage of peeled lattices is 5% or more but less than 10%. Grade D: The percentage of peeled lattices in the cross-cut area is 10% or more but less than 15%. Grade E: In the cross-cut portion, the percentage of lattices with peeling is 15% or more but less than 20%.

[0058] <Evaluation of abrasion resistance after heat resistance test> A 3cm square Si wafer was used as the substrate, and the resulting laminate was subjected to a heat resistance test at 400°C for 24 hours. Following the pencil hardness test of JIS K5600-5-4:1999, a 9H-H pencil was used to scratch the thin film-formed surface of the laminate, and the hardness of the pencil at which scratches began to form was determined. The evaluation criteria are shown below. "Evaluation A," "Evaluation B," "Evaluation C," and "Evaluation D" are considered passing, while "Evaluation E" is considered failing. Rating A: Pencil hardness is 9H or more. Rating B: Pencil hardness is 6H or more and less than 9H. Rating C: Pencil hardness is 4H or more and less than 6H. Rating D: Pencil hardness is 2H or more and less than 4H. Evaluation E: Pencil hardness is H or more but less than 2H.

[0059] <Evaluation of surface roughness (Ra) after heat resistance test> A 3cm square Si wafer was used as the substrate, and the resulting laminate was subjected to a heat resistance test at 400°C for 24 hours. After that, a measurement test was carried out using a surface profiler in accordance with JIS B0601 to determine the surface roughness (Ra) of the laminate's thin film-formed surface. Measurements were taken five times at equal intervals within a 1cm square in the center of the thin film-formed surface, and the average was calculated. The evaluation criteria are shown below. Note that "Evaluation A," "Evaluation B," "Evaluation C," and "Evaluation D" are acceptable, while "Evaluation E" is unacceptable. Evaluation A: The surface roughness (Ra) is less than 0.3 nm. Evaluation B: The surface roughness (Ra) is 0.3 nm or more and less than 0.5 nm. Evaluation C: Surface roughness (Ra) is 0.5 nm or more and less than 1.0 nm. Evaluation D: The surface roughness (Ra) is 1.0 nm or more and less than 5.0 nm. Evaluation E: Surface roughness (Ra) is 5.0 nm or more and less than 10 nm.

[0060] [Table 1]

[0061] [Table 2]

[0062] [Table 3]

[0063] [Table 4]

[0064] [Table 5]

[0065] [Table 6]

[0066] In Example 1-30, the film-forming aid represented by the general formula (1) was used for film formation, and therefore the mechanical strength and heat resistance of the obtained silica-containing alumina film were satisfactory compared to Comparative Example 1, which did not contain this aid. Furthermore, in Example 1-24, the molar ratio of aluminum atoms of the aluminum-containing compound to silicon atoms of the silicon-containing compound contained in the film-forming coating liquid used was 0.1 to 10, and the molar ratio of the film-forming aid to the total of the silicon atoms and the aluminum atoms was 5 to 80, and therefore the mechanical strength and heat resistance of the silica-containing alumina film were superior to those of Experimental Examples 25-28.

[0067] In Example 29, the silicon-containing compound contained in the film-forming coating solution used was polysilazane, and ozone was used as the oxygen source.Compared to Examples 1-24, the mechanical strength and heat resistance of the obtained silica-containing alumina film were lower, but still satisfactory.

[0068] In Example 30, a two-tank system was used, and a coating solution containing a film-forming aid and a solvent, and a metal source solution containing a silicon-containing compound, an aluminum-containing compound, and a solvent were separately atomized to form a silica-containing alumina film. The mechanical strength and heat resistance of the obtained silica-containing alumina film were satisfactory.

[0069] In addition, in Comparative Example 1, the film was formed without using a film-forming auxiliary, and therefore the mechanical strength and heat resistance of the obtained silica-containing alumina film were lower than those of Example 1-30, in which the film was formed using a film-forming auxiliary.

[0070] In addition, in Comparative Example 2, the film was formed by the sol-gel method (dip coating), and therefore the mechanical strength and heat resistance of the obtained silica-containing alumina film were lower than those of Example 1-29, in which the film was formed using mist CVD.

Claims

1. A compound represented by the general formula (1): used in forming a silica-containing alumina film by chemical vapor deposition. 【Chemistry 1】 (R in the formula １ and R ２ are each independently a hydrogen atom, a hydrocarbon group having 1 to 18 carbon atoms, an amino group, a hydroxyl group, or an alkoxy group having 1 to 3 carbon atoms, and R １ and R ２ may be bonded to each other to form a heterocycle.

2. A film-forming coating liquid comprising the film-forming aid according to claim 1 and a solvent.

3. The film-forming coating liquid according to claim 2 , comprising a silicon-containing compound and an aluminum-containing compound.

4. the molar ratio of aluminum atoms of the aluminum-containing compound to silicon atoms of the silicon-containing compound (moles Al / moles Si) is 0.01 to 20; 4. The film-forming coating fluid according to claim 3, wherein a molar ratio of the compound to the total of the silicon atoms and the aluminum atoms (moles of the compound / (moles of Al+moles of Si)) is 1 to 100.

5. 5. The film-forming coating liquid according to claim 3, wherein the silicon-containing compound is an alkoxysilane having 4 to 20 carbon atoms.

6. A laminate having a silica-containing alumina film formed on a surface of a substrate from the film-forming coating liquid according to any one of claims 2 to 4 and having a thickness of 10 µm or less.

7. 7. The laminate according to claim 6, wherein the silica-containing alumina film has a composition formula: SiaAlbOcTd (wherein Si is a silicon atom, Al is an aluminum atom, O is an oxygen atom, and T is an atom or atoms other than Si, Al, and O; a, b, c, and d are weight ratios, a+b+c+d=100, a is 3 or more and 45 or less, b is 3 or more and 50 or less, c is 35 or more and 70 or less, and d is 0 or more and 40 or less).

8. a mist-forming step of forming the film-forming coating liquid according to claim 3 or 4 into a mist; The method for forming a silica-containing alumina film by chemical vapor deposition includes a step of supplying the obtained mist to a heated substrate surface and causing a reaction on the substrate.

9. a two-tank mist-forming step in which the film-forming coating solution according to claim 2 and a metal source solution containing a silicon-containing compound and an aluminum-containing compound are separately misted; A method for forming a silica-containing alumina film by chemical vapor deposition, comprising the steps of supplying each mist to a heated substrate surface and causing a reaction on the substrate.

10. 10. The method for forming a silica-containing alumina film by chemical vapor deposition according to claim 9, wherein the molar ratio of the compound to the sum of silicon atoms of the silicon-containing compound and aluminum atoms of the aluminum-containing compound (moles of the compound / (moles of Al+moles of Si)) is 1 to 100.

Images