Coated Substrate

The present disclosure relates to a coated substrate.

Patent Literatures 1 to 4 disclose coated substrates having metal oxide films. In Patent Literatures 1 to 4, a wet film-formation method is employed. Meanwhile, in some cases, a dry film-formation method (dry process) has been employed so as to perform thickness control in accordance with complex substrate shapes.

In consideration of application to various fields and mass production, conventional coated substrates are not necessarily satisfactory, and development of a novel coated substrate has been desired.

The present disclosure was made in view of the above-described circumstances, and an object is to provide a novel coated substrate which can be applied to various fields and can be mass produced. The present disclosure can be realized as the following modes.

[1] A coated substrate in which a substrate is coated with a film, wherein

[2] The coated substrate recited in [1], wherein a portion of the substrate where the film is formed is electrically conductive.

[3] The coated substrate recited in [1] or [2], wherein the film contains a compound having at least one type of structure selected from C—H bond, C═O bond, and C—O bond.

[4] The coated substrate recited in [1] or [2], wherein the x-ray photoelectron spectroscopic measurement of the film shows that the percent element composition of a halogen element is 0.1 atm % or greater.

[5] The coated substrate recited in [1] or [2], wherein the metal element is at least one or more metal elements selected from the group consisting of Al (aluminum), Ti (titanium), Mo (molybdenum), Cr (chromium), Mn (manganese), Fe (iron), Co (cobalt), Ni (nickel), Zr (zirconium), V (vanadium), W (tungsten), Ta (tantalum), Nb (niobium), and Sn (tin).

According to the present disclosure, there is provided a novel coated substrate which can be applied to various fields and can be mass produced.

The present disclosure will now be described in detail. Notably, in the present specification, in a description in which “-” is used for a numerical range, the numerical range contains its upper and lower limit values, unless otherwise specifically noted. For example, a description of “10-20” should be read to contain both “10” (lower limit value) and “20” (upper limit value). Namely, “10-20” has the same meaning as “10 or greater and 20 or less.” Also, in the present specification, the upper and lower limit values of various numerical ranges may be combined freely.

A coated substrateincludes a substratecoated with a film. The thickness of the filmis 1 nm or greater and less than 800 nm. X-ray photoelectron spectroscopic measurement of the filmshows that the percent element composition of C (carbon) is 0.1 atm % or greater and less than 20 atm %, and the total percent element composition of a metal element and O (oxygen) is 70 atm % or greater. The relative density of the filmis 90% or greater. The filmis amorphous.

No particular limitation is imposed on the substrate. In order to enhance adhesion of the filmto the substrate, at least a portion (region) of the substrate, which portion is to be coated with the film, is preferably formed of a material which is electrically conductive and can function as a negative electrode(cathode). In the case where the portion (region) of the substrate, which portion is to be coated with the film, is electrically conductive and can function as the negative electrode(cathode), the filmcan be easily formed on that portion by a manufacturing method described below.

A surface portion of the substratemay be formed of a material which is electrically conductive and can function as the negative electrode. The entire substratemay be formed of a material which can function as the negative electrode. Examples of preferred materials which can serve as the negative electrodeinclude an iron-based alloy and carbon. An example of preferred iron-based alloys is one or more types of alloys selected from Fe—Ni—Cr alloy (stainless steel), Fe—Ni alloy (permalloy), Fe—Si alloy (silicon iron), Fe—Si—Al alloy (Sendust), Fe—Ni—Mo (supermalloy), Fe—Co alloy (permendur), and Fe—C—B alloy (amorphous).

From the viewpoint of enabling the filmto exhibit a function corresponding to the material of the film, the thickness of the filmis 1 nm or greater, preferably 10 nm or greater, more preferably 50 nm or greater. Meanwhile, from the viewpoint of enabling the filmto endure stresses generated therein and securing adhesion to the substrate, the thickness of the filmis less than 800 nm, preferably 500 nm or less, more preferably 200 nm or less. From theses viewpoints, the thickness of the filmis 1 nm or greater and less than 800 nm, preferably 10 nm or greater and 500 nm or less, more preferably 50 nm or greater and 200 nm or less. Notably, in the case where the thickness of the filmis not uniform, the filmsatisfies the requirement regarding the thickness when the thickness of at least a portion of the filmfalls within the above-described range. The thickness of the filmcan be obtained through observation under an FIB-SEM.

From the viewpoint of suppressing growth of crystal grains in the filmand stabilizing the properties of the film, the percent element composition of C (carbon) determined through measurement by x-ray photoelectron spectroscopy (XPS method) is 0.1 atm % or greater, preferably 0.5 atm % or greater, more preferably 1 atm % or greater. Meanwhile, from the viewpoint of enabling the filmto sufficiently function as an inorganic film, the percent element composition of C (carbon) is less than 20 atm %, preferably 15 atm % or less, more preferably 10 atm % or less. From these viewpoints, the percent element composition of C (carbon) is 0.1 atm % or greater and less than 20 atm %, preferably 0.5 atm % or greater and 15 atm % or less, more preferably 1 atm % or greater and 10 atm % or less. Notably, in the case where the composition of the filmis not uniform, the filmsatisfies the requirement regarding the percent element composition of C (carbon) when the composition of at least a portion of the filmfalls within the above-described range.

The composition analysis by the x-ray photoelectron spectroscopy can be performed by using an x-ray photoelectron spectrometer. The measurement can be performed by scanning a cross section under the following measurement conditions: K-alpha rays of aluminum being used as an x-ray source, the beam diameter being set to 100 μm, and the x-ray incident angle in relation to a surface to be analyzed being set to 45°.

From the viewpoint of enabling the filmto sufficiently function as an inorganic film, the total percent element composition of the metal element and O (oxygen) of the filmdetermined through measurement by the x-ray photoelectron spectroscopy (XPS method) is 70 atm % or greater, preferably 80 atm % or greater, more preferably 90 atm % or greater. Notably, the upper limit of the total percent element composition of the metal element and O (oxygen) is a value obtained by subtracting the percent element composition (atm %) of C (carbon) from 100 atm %. In the case where the composition of the filmis not uniform, the filmsatisfies the requirement regarding the total percent element composition of the metal element and O (oxygen) when the composition of at least a portion of the filmfalls within the above-described range.

From the viewpoint of enabling the filmto sufficiently exhibit the function of the film, the relative density of the filmis 90% or greater, preferably 95% or greater, more preferably 98% or greater. The relative density of the filmmay be 100%.

The relative density of the filmis obtained by the following method. A TEM image of a cross section of the filmobtained by cutting the filmin the film-thickness direction is obtained. The area of pores in a field of view of 300 nm (vertical dimension)×1000 nm (horizontal dimension) is measured. The relative density (%) is obtained in accordance with the following expression (1). The average of the relative densities of 10 fields of view is the relative density of the film. Notably, in the case where the thickness of the filmis smaller than the vertical size of 300 nm, measurement is performed in fields of view determined in accordance with the thickness of the film.

(In the expression, S1 is the area (nm) of the field of view of 300 nm (vertical dimension)×1000 nm (horizontal dimension), and S2 is the total area (nm) of pores in the field of view of 300 nm (vertical dimension)×1000 nm (horizontal dimension))

The filmis amorphous. The fact that the filmis amorphous can be confirmed by using a TEM image. Since the filmis amorphous, it is expected that crystal grains do not come off and peculiar functions (such as smoothing the outermost surface by uniform film growth) are exhibited.

(2.6) Compound Having at Least One Type of Structure Selected from C—H Bond, C═O Bond, and C—O Bond

The filmpreferably contains a compound having at least one type of structure selected from C—H bond, C—O bond, and C—O bond. Since the compound having at least one type of structure selected from C—H bond, C═O bond, and C—O bond vaporizes at a lower temperature as compared with elemental C (carbon) and induces contraction of the film, it is supposed that the denseness of the filmincreases.

Also, since the compound having at least one type of structure selected from C—H bond, C—O bond, and C—O bond remains, it is supposed that the flexibility of the filmis maintained, and the adhesion of the filmto the substrateis enhanced.

The percent element composition of the halogen element as determined through measurement of the filmby x-ray photoelectron spectroscopy is preferably 0.1 atm % or greater, more preferably 0.3 atm % or greater, further preferably 0.5 atm % or greater. The upper limit value of the percent element composition of the halogen element is 3 atm % or less.

Since a small amount of halogen element is contained in the film, conceivably, the oxide film present on the surface of the substrateis removed by the action of the halogen element, and the filmcomes into direct contact with the substrate. As a result, the adhesion between the substrateand the filmis secured.

No particular limitation is imposed on the metal element. From the viewpoint of causing the filmto function as a high quality protection film for the substrate, the metal element is preferably at least one or more metal elements selected from the group consisting of Al (aluminum), Ti (titanium), Mo (molybdenum), Cr (chromium), Mn (manganese), Fe (iron), Co (cobalt), Ni (nickel), Zr (zirconium), V (vanadium), W (tungsten), Ta (tantalum), Nb (niobium), and Sn (tin).

No particular limitation is imposed on a method for manufacturing the coated substrateof the present disclosure.

A preferred manufacturing method will now be described below. The preferred manufacturing method is a method for manufacturing the coated substrateby using a bath liquidcontaining an organic solvent. The water content of the bath liquidis less than 1 mass % and the bath liquidcontains at least one or more types of metal elements and at least one or more types of halogen elements. When a voltage is applied in a state in which the substrateis immersed in the bath liquid, the filmis formed on the substrate, which serves as a negative electrode(cathode). In the manufacturing method of the present disclosure, since electrodeposition is taken place on the negative electrodeside, oxidation of the substratecan be suppressed as compared with the case where electrodeposition is taken place on the positive electrodeside (anode side).

The bath liquidcontains an organic solvent.

From the viewpoint of guaranteeing the homogeneity of the filmand suppressing oxidation of the substrate, the water content of the bath liquidis rendered less than 1 mass %. The water content is preferably less than 0.5 mass %, more preferably less than 0.1 mass %. The water content may be 0 mass %. The water content of the bath liquidcan be obtained by GC-MS analysis.

The bath liquidcontains at least one or more types of metal elements. No particular limitation is imposed on the metal elements. From the viewpoint of causing the filmto function as a high quality protection film for the substrate, the metal element is preferably at least one or more metal elements selected from the group consisting of Al (aluminum), Ti (titanium), Mo (molybdenum), Cr (chromium), Mn (manganese), Fe (iron), Co (cobalt), Ni (nickel), Zr (zirconium), V (vanadium), W (tungsten), Ta (tantalum), Nb (niobium), and Sn (tin). In the manufacturing method of the present disclosure, an oxide film depending on the metal element(s) in the bath liquidis formed as the film.

The metal element(s) contained in the bath liquidmay be supplied as a result of elution of the positive electrode(anode). In the case where the metal element(s) elutes from the positive electrodeinto the bath liquid, control of film formation speed becomes easy, and continuous and stable formation of films on a plurality of substratesbecomes possible. In the case where the metal element(s) is supplied to the bath liquidas a result of elution of the positive electrode, at least one or more types of electrodes selected from an electrode of Al, an electrode of Ti, and an electrode of Mo are preferably used as the positive electrode.

The metal element(s) in the bath liquidmay be supplied from a metal alkoxide and/or an inorganic metal compound. In the case where the metal element(s) is supplied as a result of dissolution of a metal alkoxide and/or an inorganic metal compound, it is possible to cope with an element which is difficult to supply by eluting the positive electrode(anode). Also, in this case, it becomes possible to perform film formation in which composition ratios are controlled by combining a plurality of metal elements.

Examples of the metal alkoxide include an aluminum alkoxide, a titanium alkoxide, and a molybdenum alkoxide.

Examples of the aluminum alkoxide include an aluminum trialkoxide. Examples of the aluminum trialkoxide include aluminum tripropoxides (e.g., aluminum triisopropoxide and aluminum tri-n-propoxide), aluminum triethoxide, aluminum tributoxides (e.g., aluminum tri-sec-butoxide and aluminum tri-n-butoxide).

Examples of the titanium alkoxide include a titanium trialkoxide, a titanium tetraalkoxide, and a titanium tetraalkoxide is preferred. Examples of the titanium tetraalkoxide include titanium tetrapropoxides (e.g., titanium tetraisopropoxide and titanium tetra-n-propoxide), titanium tetramethoxide, titanium tetraethoxide, titanium tetrabutoxides (e.g., titanium tetraisobutoxide and titanium tetra-n-butoxide), titanium tetrapentoxides, titanium tetrahexoxides, and titanium tetra (2-ethylhexoxide).

Examples of the inorganic metal compound include aluminum chloride, aluminum bromide, aluminum iodide, and titanium iodide.

In the case where the metal element(s) in the bath liquidis supplied from a metal alkoxide and/or an inorganic metal compound, no particular limitation is imposed on the metal element concentration of the bath liquid. In this case, from the viewpoint of forming a satisfactory film, the metal element concentration of the bath liquidis preferably 1 ppm or greater and 100 ppm or less, more preferably 3 ppm or greater and 10 ppm or less, further preferably 4 ppm or greater and 6 ppm or less. Notably, “ppm” means “parts per million” and “mg/L.” Notably, in the case where the bath liquidcontains a plurality of metal elements, the above-described metal element concentration means the total concentration with respect to the plurality of metal elements. The metal element concentration of the bath liquidcan be measured by ICP-MS analysis.

The bath liquidcontains at least one or more types of halogen elements. Since the bath liquidcontains a halogen element(s), film formation is performed at a practical speed, and the filmis likely to become homogeneous. No particular limitation is imposed on the halogen element. From the viewpoint of enabling prompt progress of organic electrochemical reactions and causing the filmto function as a high quality protection film for the substrate, the halogen element(s) is preferably at least one or more halogen elements selected from the group consisting of Cl (chlorine), Br (bromine), and I (iodine).

No particular limitation is imposed on the halogen element concentration of the bath liquid. From the viewpoint of moderately reducing reaction speed, being advantageous for control of the homogeneity and thickness of the film, and preventing separation of the film, the halogen element concentration of the bath liquidis preferably 1 ppm or greater and 20000 ppm or less, more preferably 5 ppm or greater and 2000 ppm or less, further preferably 10 ppm or greater and 100 ppm or less. Notably, “ppm” means “parts per million” and “mg/L.” The halogen element concentration of the bath liquidcan be obtained from the amount of a halogen element(s) added at the time of making-up of the electrolytic bath or by ICP-MS analysis.

Since an organic solvent is used as the solvent of the bath liquid, generation of gas and oxidation of the substrateitself during film formation are suppressed. From the viewpoint of satisfactory formation of the film, the solvent preferably contains at least one or more types of solvents selected from the group consisting of ketones and nitriles. In the case where the solvent contains a ketone and/or a nitrile, it is supposed that a condensation reaction occurs on the electrode surface (cathode surface) and electrodeposition becomes possible. Also, in the case where the solvent contains a ketone, conceivably, ketoenol tautomerism occurs in the presence of halogen, and the reactivity of the bath liquidis enhanced.

No particular limitation is imposed on the ketone so long as the ketone is an organic solvent having a carbonyl group (—C(═O)—) other than ester bond.

Examples of the ketone include acetone, methyl ethyl ketone (MEK), 1-hexanone, 2-hexanone, 4-heptanone, 2-heptanone (methyl amyl ketone), 1-octanone, 2-octanone, 1-nonanone, 2-nonanone, diisobutyl ketone, methyl isobutyl ketone, acetylacetone, acetonylacetone, phenylacetone, acetophenone, methyl naphthyl ketone, cyclohexanone (CHN), and methylcyclohexanone. Among these, acetone and methyl ethyl ketone are preferred, because the filmis formed particularly satisfactorily.

Nitrile is an organic solvent which contains a nitrile group (—CN) in its structure. Examples of the nitrile include acetonitrile, propionitrile, valeronitrile, and butyronitrile. Among these, acetonitrile is preferred, because the filmis formed particularly satisfactorily.

As to the “substrate,” the description in the column entitled “(1) Substrate” in the above-described section entitled “1. Coated substrate” is applied as it is.

By applying a voltage to the substrateimmersed in the bath liquid, a filmis formed on the substrate, which serves as the negative electrode. Specifically, the positive electrodeand the negative electrode(the substrate) are immersed into the bath liquid, and a potential gradient is generated between the two electrodes.