Nickel-based alloy plating solution

Abstract

To provide a plating solution and a plating method, having excellent uniform electrodeposition properties and enabling formation of a Ni-Cr-(Mo / W)-based alloy film with more uniform composition and thickness.SOLUTION: Provided is a plating solution for forming a Ni-Cr-(Mo / W)-based alloy film, containing metal ion sources that include ion sources of nickel, chromium, and molybdenum and / or tungsten, and a complexing agent, where the amount of the complexing agent relative to the total amount of the metal ion sources is 0.01 to 2 equivalents inclusive. Also provided is a method for forming a Ni-Cr-(Mo / W)-based alloy film, including a step of performing plating with the use of the plating solution.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a plating solution for forming a nickel-based alloy film.

Background Art

[0002] Conventionally, nickel-based alloys such as HASTELLOY (registered trademark) have been widely used as heat-resistant materials and corrosion-resistant materials. These nickel-based alloys are excellent in heat resistance and corrosion resistance, exhibit high durability against various chemical substances such as halogens and oxidizing or non-oxidizing substances, are less likely to cause pitting corrosion and crevice corrosion, and have the advantage of being resistant to stress corrosion cracking.

[0003] Due to these advantages, nickel-based alloys can be used in high-temperature environments and corrosive environments. On the other hand, they have the disadvantages of being hard and difficult to form. Therefore, materials using nickel-based alloys are difficult to process into complex shapes, and together with the high cost of the material itself, they tend to be costly. Nickel-based alloys also have the disadvantage that they have a relatively high specific gravity, making it difficult to reduce the weight of the material.

[0004] If a nickel-based alloy can be applied to various materials in the form of a surface film, the difficulty of formability can be solved, and cost reduction and weight reduction can also be facilitated. Based on such an idea, attempts have been made to form a nickel-based alloy film by plating.

[0005] For example, Patent Document 1 discloses a method for plating an alloy using a plating bath containing chromium ions, nickel and / or cobalt ions, and tungstic acid, molybdic acid, and / or rhenium acid ions at specific concentrations. Patent Document 2 discloses a plating solution having a pH of 8 to 11 in which gluconate is selected as a complexing agent for nickel-based alloy plating and is blended with a nickel salt and a molybdate in order to improve the formation efficiency and appearance of the plating film.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] In the conventional method as described above, a nickel-based alloy plating film that is uniform and excellent in corrosion resistance and the like cannot always be obtained. For example, in the plating method described in Patent Document 1, as shown in the examples described later, uniform electrodeposition of a nickel-chromium-molybdenum alloy film is difficult. Similar problems can also occur in the plating solution described in Patent Document 2 in which the type of complexing agent is considered. In the nickel-molybdenum alloy plating solution described in Patent Document 2, since it does not contain chromium ions, it is difficult to exhibit sufficient acid resistance and the like. Even if a chromium salt is simply added to this plating solution, a uniform plating film with a good appearance cannot always be obtained.

[0008] An object of the present invention is to provide a plating solution that is excellent in uniform electrodepositing property and can form a film of a nickel-chromium-molybdenum and / or tungsten-based alloy with a more uniform composition and film thickness in order to solve the above-described problems, and a method for forming a plating film using the plating solution.

Means for Solving the Problems

[0009] The present inventors have found that when forming a film of a nickel-chromium-molybdenum and / or tungsten-based alloy (Ni-Cr-(Mo / W)-based alloy), by setting the ratio of the amount of the complexing agent to the amount of the ion source within a specific range, specifically, 2 equivalents or less, a nickel-based alloy film can be obtained without significant variations in composition and film thickness, and thus the present invention has been completed.

[0010] That is, the present invention provides the following (1) to (8). (1) A plating solution containing a metal ion source including an ion source of nickel, chromium, and molybdenum and / or tungsten, and a complexing agent, wherein the amount of the complexing agent with respect to the total amount of the metal ion source is 0.01 equivalent or more and 2 equivalents or less, the plating solution for forming a Ni-Cr-(Mo / W) based alloy film. (2) The plating solution according to (1) above, further containing a conductive salt. (3) The plating solution according to (2) above, wherein the conductive salt contains a sulfate. (4) The plating solution according to any one of (1) to (3) above, further containing a pH adjuster containing a hydroxide of an alkali metal. (5) The plating solution according to any one of (1) to (4) above, wherein the complexing agent is at least one selected from the group consisting of carboxylic acids, carboxylates, hydroxycarboxylic acids, hydroxycarboxylates, amino acids, amino acid salts, and alcohols. (6) The plating solution according to any one of (1) to (5) above, further containing a pH buffer. (7) The plating solution according to any one of (1) to (6) above, wherein the concentration of nickel is 0.001 to 0.5 mol / L in terms of element, the concentration of chromium is 0.01 to 1.5 mol / L in terms of element, and the total concentration of molybdenum and tungsten is in the range of 0.001 to 2.0 mol / L in terms of element. (8) A method for forming a Ni-Cr-(Mo / W) based alloy film, including a step of plating using the plating solution according to any one of (1) to (7) above.

Advantages of the Invention

[0011] The plating solution of the present invention is excellent in uniform electrodeposition property, and according to the plating solution and method of the present invention, a Ni-Cr-(Mo / W) based alloy film can be formed without significant variations in composition and film thickness.

Brief Description of the Drawings

[0012]

Figure 1

Best Mode for Carrying Out the Invention

[0013] Hereinafter, the present invention will be described in detail based on embodiments, but the present invention is not limited to these embodiments.

[0014] ≪1. Plating Solution≫ The plating solution according to this embodiment is a plating solution for forming a Ni-Cr-(Mo / W) alloy film containing a metal ion source containing an ion source of nickel, chromium, and molybdenum and / or tungsten, and a complexing agent. And the amount of the complexing agent with respect to the total amount of the metal ion source is 0.01 equivalent or more and 2 equivalents or less.

[0015] <Metal Ion Source> The metal ion source contained in the plating solution contains at least an ion source of nickel, chromium, and molybdenum and / or tungsten.

[0016] As these ion sources, for example, nickel salts, chromium salts, various chromates, molybdenum salts, various molybdates, tungsten salts, and various tungstates are common, and these can also be used in this embodiment. It is also possible to use a plurality of types of ion sources of the same metal, for example, a chromium salt and a chromate, in combination. Also, a salt such as nickel molybdate can be used. In addition to these, salts of complex ions such as ammonium complexes and cyano complexes of various metal ions may be used. However, in order to optimize the content ratio with the other essential component, the complexing agent, and form a plating film with a uniform composition and film thickness, it is preferable to use a metal salt or metal acid salt that is not a complex as the metal ion source.

[0017] More preferred metal ion sources are nickel salts, chromium salts, molybdates, and tungstates. Among them, halides, sulfates, sulfites, nitrates, nitrites, perchlorates, etc. of nickel and chromium, as well as sodium salts, potassium salts, and ammonium salts of molybdic acid and tungstic acid, etc. are preferred. In particular, nickel sulfate, chromium sulfate, basic chromium sulfate, ammonium molybdate, and ammonium tungstate are suitable as the metal ion sources in this embodiment. With a plating solution containing these metal ion sources, a film of a Ni-Cr-(Mo / W) alloy having high corrosion resistance can be formed with a more uniform composition and film thickness.

[0018] The plating solution may further contain ion sources of other metals as the metal ion source, such as iron (Fe), cobalt (Co), manganese (Mn), copper (Cu), titanium (Ti), niobium (Nb), aluminum (Al), etc. By using these ion sources of other metals in combination, for example, Hastelloy X containing a small amount of Mn and Co in a Ni-Cr-Mo-Fe system, and further nickel-based alloy films with compositions such as INCONEL, INCOLOY, Waspaloy, DASALOY (registered trademark), etc. can also be formed. If desired, phosphates, silicates, etc. can be used in combination to form a plating solution for a nickel-based alloy film containing phosphorus (P) and silicon (Si). According to the plating solution of this embodiment, it may also be possible to form an alloy film with a composition that cannot be made by metallurgical methods.

[0019] <Complexing agent> The plating solution of this embodiment contains a complexing agent together with the metal ion source. In this embodiment, the complexing agent may be of any type as long as its amount is appropriate as described later, and conventional ones can be used.

[0020] Specifically, the complexing agents include cyanides; various carboxylic acids and their salts; various amino acids and their salts; phosphorus-containing compounds such as pyrophosphates, nitrilotrimethylphosphonic acid and their salts, tris(3-hydroxypropyl)phosphine; sulfur-containing compounds such as thiourea, thioglycolic acid, thiodiglycolic acid, thioglycol, thiodiglycol, mercaptosuccinic acid, 3,6-dithia-1,8-octanediol, 3,6,9-trithiadodecane-1,11-disulfonic acid, thiobis(dodecaethylene glycol), bis(6-methylbenzothiazolyl)disulfide trisulfonic acid, bis(6-chlorobenzothiazolyl)disulfide disulfonic acid, dithiodianiline, dipyridyl disulfide, mercaptosuccinic acid, sulfites, thiosulfates; and alcohols; and further include ethylenediamine, ascorbic acid, gluconolactone, glucoheptonolactone, etc., but are not limited thereto. It is also possible to use a combination of multiple complexing agents.

[0021] Also, as the complexing agent, preferably, one or more selected from the group consisting of carboxylic acids, carboxylates, hydroxycarboxylic acids, hydroxycarboxylates, amino acids, amino acid salts, and alcohols are used. With a plating solution containing an appropriate amount of such a complexing agent, it becomes possible to form a nickel-based alloy plating film with a more uniform composition and film thickness. Particularly among these, carboxylic acids, hydroxycarboxylic acids, and their salts are particularly preferred, especially hydroxycarboxylic acids. Hereinafter, these complexing agents will be described more specifically, but the complexing agents that can be components of the plating solution of the present embodiment are not limited to the following.

[0022] (Carboxylic acids and their salts) Examples of carboxylic acids suitable as complexing agents include aliphatic monocarboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, and hexanoic acid; aliphatic dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, maleic acid, and malic acid; aliphatic tricarboxylic acids such as aconitic acid; aromatic carboxylic acids such as benzoic acid, salicylic acid, phthalic acid, and cinnamic acid. Examples of carboxylates include their sodium salts, potassium salts, ammonium salts, etc. Note that salts of carboxylic acids having multiple carboxy groups may be those in which only some of the carboxy groups form salts, double salts, such as sodium hydrogen oxalate and potassium sodium oxalate, etc.

[0023] (Hydroxycarboxylic acids and their salts) Examples of hydroxycarboxylic acids suitable as complexing agents include glycolic acid, gluconic acid, citric acid, glucoheptonic acid, tartaric acid, diglycolic acid, etc. Examples of hydroxycarboxylates include their sodium salts, potassium salts, ammonium salts, etc. For example, it may be sodium hydrogen tartrate, potassium sodium tartrate, etc.

[0024] (Amino acids and their salts) Examples of amino acids (aminocarboxylic acids) suitable as complexing agents include glycine, α-alanine, β-alanine, cystine, anthranilic acid, aspartic acid, glutamic acid, aminodiacetic acid, ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), nitrilotriacetic acid (NTA), iminodiacetic acid (IDA), iminodipropionic acid (IDP), hydroxyethylethylenediaminetriacetic acid (HEDTA), triethylenetetraminehexaacetic acid (TTHA), ethylenedioxybis(ethylamine)-N,N,N’,N’-tetraacetic acid, and further aromatic amino acids such as pyridinedicarboxylic acid. Examples of amino acid salts include their sodium salts, potassium salts, ammonium salts, etc.

[0025] (Alcohols) Examples of alcohols suitable as a complexing agent include glycols such as ethylene glycol, propylene glycol, and diethylene glycol.

[0026] <Amount of metal ion source and amount of complexing agent> The plating solution of the present embodiment is characterized in that the amount of the complexing agent with respect to the total amount of the metal ion source is 0.01 equivalent or more and 2 equivalents or less. By setting the ratio of the amount of the complexing agent to the amount of the metal ion source within the range of 0.01 to 2 equivalents, the uniform electrodepositing property of the plating solution can be improved, and a nickel-based alloy film can be formed with a more uniform composition and film thickness.

[0027] Generally, in alloy plating, since a plurality of metals having different deposition potentials are used, in order to form a desired alloy film with a uniform composition, a large amount of a complexing agent more than the amount of the metal ion source is used. For example, also in the case described in Patent Document 1, a plurality of kinds of organic acids are used as a complexing agent in a total amount of more than 2 equivalents to about 4 equivalents with respect to the total molar amount of metal ions. Also in the nickel-molybdenum alloy plating solution described in Patent Document 2, when the amount of the complexing agent is about 2 equivalents with respect to the amount of the metal ion source, the deposition current efficiency of the plating film does not increase, and particularly decreases greatly when it is 1 equivalent or less. This time, in the formation of a plating film of a nickel, chromium, and molybdenum and / or tungsten-based alloy (Ni-Cr-(Mo / W) based alloy), an unexpected effect that a plating solution excellent in uniform electrodepositing property can be obtained by setting the amount of the complexing agent with respect to the total amount of the metal ion source to a small amount of 0.01 to 2 equivalents was exhibited.

[0028] Here, "equivalent" means the ratio of the molar amount of the complexing agent molecule to the total molar amount of the metal ions constituting the plating film.

[0029] In addition, the "total amount of metal ion sources" means the total molar amount of all ion sources for the metal constituting the target plating film. For example, when forming a Ni-Cr-(Mo / W) alloy film, it means the total molar amount of nickel, chromium, and molybdenum and / or tungsten; when forming a Ni-Cr-(Mo / W)-Fe alloy film, it means the total molar amount of nickel, chromium, molybdenum and / or tungsten, and iron, respectively. The amount of a metal that does not constitute the plating film, such as an alkali metal in molybdate, is not included. Generally, it means the total molar amount of metals in Groups 3 to 15, for example, Groups 4 to 14 in the plating solution.

[0030] Note that the "molar amount of metal ion sources" is a value based on the metal element. For example, when 0.1 mol of Cr2(SO4)3 is contained in the plating solution, the amount of chromium ion sources is calculated as 0.2 mol.

[0031] (Concentration of metal components) Regarding the concentration of each metal component in relation to the amount of metal ion sources, the concentration of the metal component in the plating solution of this embodiment can be arbitrarily set according to the type of the target plating film, the conditions of the plating process, etc. For example, the concentration of nickel can be set to 0.001 to 0.5 mol / L in terms of element conversion, the concentration of chromium can be set to 0.01 to 1.5 mol / L in terms of element conversion, and the total concentration of molybdenum and tungsten can be set to 0.001 to 2.0 mol / L in terms of element conversion.

[0032] Alternatively, for the concentration settings of these metal components, in all cases, the nickel concentration is 0.001 to 0.5 mol / L, particularly 0.01 to 0.1 mol / L, the chromium concentration is 0.01 to 1.5 mol / L, particularly 0.1 to 1.0 mol / L, the molybdenum concentration is 0.001 to 2.0 mol / L, particularly 0.01 to 1.0 mol / L in terms of element conversion. If desired, tungsten can be set to a concentration of about 0.001 to 2.0 mol / L, particularly 0.01 to 1.0 mol / L, in the form of replacing molybdenum or adding to molybdenum.

[0033] In the plating solution of the present embodiment, as described above, the amount of the complexing agent with respect to the total amount of the metal ion source, that is, the molar ratio of the amount of the complexing agent / the total amount of the metal ion source is set to 0.01 equivalent or more and 2 equivalents or less. Preferably, the molar ratio of the amount of the complexing agent / the total amount of the metal ion source is, for example, 0.05 equivalent or more, more preferably 0.10 equivalent or more, still more preferably 0.20 equivalent or more, even more preferably 0.30 equivalent or more, and particularly preferably 0.40 equivalent or more. The same molar ratio is also preferably 1.5 equivalents or less, more preferably 1.0 equivalent or less, particularly preferably 0.90 equivalent or less, and further set to 0.8 equivalent or less, or 0.6 equivalent or less, for example, 0.10 to 2.0 equivalents, particularly 0.20 to 1.5 equivalents, still more preferably 0.30 to 1.0 equivalents, and particularly 0.40 to 0.90 equivalents.

[0034] By appropriately selecting the molar ratio of the amount of the complexing agent / the total amount of the metal ion source within the range of 0.01 to 2 according to the target plating film, the type of the complexing agent, etc., a nickel-based alloy film can be formed with a more uniform composition and film thickness. Incidentally, the concentration of the complexing agent in the plating solution is mainly determined based on the total concentration of the metal ion source, but is generally preferably 0.01 to 1 mol / L, particularly about 0.1 to 0.8 mol / L.

[0035] <Solvent> In the plating solution of the present embodiment, the solvent containing the metal ion source and the complexing agent is preferably water, but alcohols such as methanol and ethanol; ethers such as tetrahydrofuran (THF), dioxane, and various glymes; carbonic acid esters such as ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate; nitrogen-containing solvents such as acetonitrile, dimethylformamide (DMF), and pyrrolidone; and sulfur-containing solvents such as dimethyl sulfoxide (DMSO) may be included. Depending on the purpose and the types of the metal salt and the complexing agent used, an organic solvent can also be used as the main solvent.

[0036] <Additive> In the plating solution of the present embodiment, together with a metal ion source and a complexing agent, various additives such as a conductivity-imparting agent including a conductive salt, a pH adjuster, a pH buffer, a hydrogen generation inhibitor, a dispersant, a dispersion aid, an emulsifier, a surfactant, a brightener, an antioxidant, a viscosity adjuster, wetting agents, and a pigment may be blended. In particular, by adding a conductive salt, a pH adjuster, and a pH buffer, it is also possible to further improve the uniform electrodeposition property of the plating solution. Hereinafter, some of these additives will be described.

[0037] (Conductive salt) There is no particular limitation on the type of the conductive salt, and various inorganic salts such as halides, sulfates, nitrates, and phosphates, and organic salts such as tetraalkylammonium salts, pyridinium salts, and sulfonates can be used. Among them, sulfates and / or ammonium salts, particularly sulfates, are preferable. In the case of a plating solution containing a sulfate or an ammonium salt as the conductive salt, the deposition of the metal for forming the target film is promoted in a well-balanced manner, and it becomes easy to form an alloy plating with a more uniform composition and film thickness. Specific examples of suitable conductive salts include sodium sulfate, potassium sulfate, ammonium sulfate, ammonium chloride, ammonium bromide, ammonium nitrate, ammonium phosphate, etc., but are not limited thereto. In particular, sodium sulfate, potassium sulfate, and ammonium sulfate are preferable.

[0038] There is no particular limitation on the concentration of these conductive salts in the plating solution, and it can be set to a desired value according to the concentration of the metal component, etc. For example, the concentration may be about 0.1 to 3 mol / L, particularly about 0.25 to 2 mol / L, but is not limited to such a range.

[0039] (pH adjuster) In order to further improve the uniform electrodeposition property, the plating solution of the present embodiment contains a pH adjuster, and the pH may be adjusted to a region suitable for nickel-based alloy plating, for example, 0.5 to 12, particularly about 0.5 to 10, further about 0.5 to 7.5, and especially about 1 to 6.

[0040] The pH adjuster is also useful in that it enables the complexing agent to function effectively. Since each complexing agent has a pH at which complex formation is likely to occur, it is preferable to adjust the pH of the plating solution before use. Alternatively, the plating solution may be subjected to an operation called "aging" in which it is maintained at a specific temperature and pH for a certain period of time. It is preferable to use a pH adjuster during such an operation.

[0041] There are no particular restrictions on the pH adjuster added to the plating solution of the present embodiment, and various acids and / or bases can be used according to the target pH during the plating process or aging. Here, when a pH adjuster containing sulfuric acid is used as the acid, or when a pH adjuster containing an alkali metal hydroxide and / or ammonia is used as the base, there is an advantage that the conductivity of the plating solution is improved, which is preferable.

[0042] (pH buffer) The plating solution of the present embodiment preferably further contains a pH buffer in order to stabilize the deposition reaction of the target metal. Incidentally, although the pH buffer can also be regarded as a kind of pH adjuster in a broad sense, here it is treated as a component different from the pH adjuster in a narrow sense. There are no particular restrictions on the type of pH buffer, and a buffer suitable for the target pH range can be selected and used from various known ones. Examples include, but are not limited to, boric acid, phosphoric acid, citric acid, acetic acid, tartaric acid, and their salts.

[0043] (Hydrogen generation inhibitor) The plating solution of the present embodiment may also contain a hydrogen generation inhibitor. When the plating solution contains a hydrogen generation inhibitor, it becomes easier to suppress a decrease in current efficiency during the plating process. Further, as a result of suppressing the generation of hydrogen gas at the cathode, it becomes easier to prevent burning and hydrogen embrittlement of the plating film. Note that burning refers to a problem in which the current density at the cathode becomes excessive, and a thick and brittle plating film is formed, and it is a phenomenon caused by precipitation of metal hydroxides accompanying an increase in pH at the cathode interface. There is no particular limitation on the hydrogen generation inhibitor, and various known ones can be used. For example, boric acid, phosphoric acid, citric acid, acetic acid, tartaric acid, and their salts can be used, and boric acid, citric acid, or their salts are particularly preferable.

[0044] When containing a hydrogen generation inhibitor, its concentration is preferably about 0.01 to 2.0 mol / L, particularly about 0.1 to 1.5 mol / L. Note that a part of these hydrogen generation inhibitors can also function as the complexing agent and pH buffer described above. Therefore, by setting the concentration of, for example, citric acid in the plating solution to about 0.01 to 2.0 mol / L, further about 0.02 to 1.5 mol / L, particularly about 0.10 to 1.0 mol / L, it is possible to exhibit all the functions of complex formation, pH adjustment, and hydrogen generation suppression.

[0045] (Brightener) The plating solution of the present embodiment may contain a brightener. The brightener not only imparts luster to the plating film, but may also exhibit a function of promoting the deposition of metal in the recesses and flattening the plating surface. There is no particular limitation on the type of brightener, and various aldehydes, triazines, imidazoles, indoles, quinolines, 2-vinylpyridine, anilines, phenanthrolines, neocuproines, picolinic acids, thioureas, benzothiazoles, sulfides, etc. can be used. When containing a brightener, its concentration is preferably about 0.01 mg / L to 500 mg / L, particularly about 0.1 mg / L to 10 mg / L.

[0046] (Surfactant) The surfactant is not particularly limited, and a desired one can be selected from ordinary anionic surfactants, cationic surfactants, nonionic surfactants, amphoteric surfactants, etc. When a surfactant is contained, its concentration is preferably about 1 mg / L to 50 g / L, particularly about 5 mg / L to 10 g / L.

[0047] (Antioxidants) The antioxidant is used to prevent oxidation of the metal salt. Examples of the antioxidant include hypophosphorous acids, ascorbic acid, phenolsulfonic acid, cresolsulfonic acid, hydroquinonesulfonic acid, hydroquinone, α- or β-naphthol, catechol, resorcin, phloroglucin, hydrazine, phenolsulfonic acid, catecholsulfonic acid, hydroxybenzenesulfonic acid, naphtholsulfonic acid, and salts thereof, but are not limited thereto. The antioxidant can be contained at a concentration of, for example, about 0.1 g / L to 500 g / L, particularly about 1 g / L to 100 g / L.

[0048] Although some representative additives have been described above, the plating solution of the present invention may contain various additives other than these. In addition, one or two types of additives may also be used as functional agents that provide multiple effects. For example, one or two types of inorganic acids such as sulfuric acid and phosphoric acid, organic acids such as carboxylic acids and sulfonic acids, bases such as ammonia, or salts thereof may be used to provide various functions such as electrical conductivity, pH adjustment, buffering action, and hydrogen generation inhibitor. The present invention also includes a plating solution for forming a Ni-Cr-(Mo / W)-based alloy film that contains an inorganic acid salt and / or an organic acid salt.

[0049] <Preparation of plating solution> The plating solution of this embodiment can be prepared from the above-mentioned components by a conventional method, and the details may be appropriately determined in consideration of the composition and amount of each component, etc. Here, in order to make the complexing agent in the plating solution function more effectively, the pH may be adjusted or a "ripening" treatment may be performed before use.

[0050] 2. Method of forming alloy film By performing plating treatment using the plating solution of the above-mentioned various embodiments, it is possible to form a desired Ni-Cr-(Mo / W)-based alloy film on various substrates. Therefore, a method for forming a Ni-Cr-(Mo / W)-based alloy film can be defined as a method including a step of performing plating treatment using the above-mentioned plating solution. According to such a method, it is possible to form a nickel-based alloy film having excellent uniform electrodeposition and uniform composition and film thickness.

[0051] There are no particular limitations on the method and conditions for plating, and for example, general electrolytic plating may be carried out under conventional conditions depending on the type of nickel-based alloy film desired and the substrate to be plated.

[0052] Specifically, the temperature of the plating solution can be about 10 to 90° C. The current density can be 0.01 to 50 A / dm 2 It can be about that.

[0053] <Plating process overview> The nickel-based alloy film can be formed, for example, by immersing an object to be plated as a cathode together with an anode in the plating solution of the present invention and passing a current through it. Here, if the solution temperature is 10°C or higher and the current density is 0.01 A / dm 2 If the solution temperature is 90°C or less, it is easy to form a nickel-based alloy film in a relatively short time. If the solution temperature is 90°C or less, changes in concentration, etc. due to evaporation or boiling of the plating solution are suppressed, making it easy to form a nickel-based alloy film with a more uniform composition and thickness. In addition, if the current density is 50 A / dm 2 If the temperature is equal to or lower than this, the occurrence of defects such as scorching in the generated alloy film is easily suppressed. Note that although the plating solution in the plating tank is sometimes called a "plating bath", in this embodiment, both are regarded as the same and are called a "plating solution".

[0054] (Plating object) Here, the object to be plated in this embodiment may be any object as long as it has conductivity. Various metal materials and conductive ceramic materials, of course, can also be used for insulators such as non-conductive ceramics, glass, carbon materials, resins, rubbers, and woods. For example, materials made conductive by electroless plating or metal vapor deposition can be used. When plating a conductive material such as metal, a material with another plating layer on the base material may also be used. There is no particular limitation on the shape of the object to be plated.

[0055] Considering the excellent heat resistance and corrosion resistance of Ni-Cr-(Mo / W) alloys such as Hastelloy, when the object to be plated is a material with heat resistance or corrosion resistance, the alloy film forming method of this embodiment can be particularly effective. For example, by forming a film of Ni-Cr-(Mo / W) alloy on a base material made of iron or stainless steel, or a material obtained by subjecting these base materials to chromium plating, nickel plating, etc., a material with particularly excellent heat resistance and corrosion resistance can be obtained. Depending on the target use temperature, a metal layer or the like may be formed in advance on the surface of a heat-resistant resin material, such as a thermoset of polyimide or its fiber composite, by electroless plating or the like, and then subjected to the plating treatment of this embodiment. The polymer material treated by the plating method of this embodiment can be utilized as a lightweight corrosion-resistant material.

[0056] (Anode) There is no particular limitation on the anode used for the plating treatment. For example, an electrode made of nickel or a nickel-based alloy may be used as the anode, and nickel, and further chromium, molybdenum, etc. may be supplied into the plating solution during the treatment. However, in order to stably proceed with the plating treatment and form a more uniform alloy film, it is preferable to use an electrode based on an insoluble material, such as iridium oxide, tantalum oxide, platinum, lead, lead alloy, boron-doped diamond, graphite, etc. as the anode. Since these anodes do not elute into the plating solution during the treatment or elute only slightly, there is no risk of changing the composition of the plating solution, and as a result, it becomes easier to form an alloy film with a more uniform composition.

[0057] <The actual plating process> Hereinafter, the plating process for forming a nickel-based alloy film on various conductive or non-conductive substrates will be described in more detail.

[0058] (Pretreatment) Prior to the plating process of the present embodiment, the substrate to be plated may be subjected to pretreatment, such as degreasing or acid activation treatment. Particularly when plating non-conductive materials such as common ceramics or resins, it is desirable to perform pretreatment such as electroless plating, sputtering, or vapor deposition in advance to form a metal layer or a graphite layer on the surface to impart conductivity.

[0059] There are no particular restrictions on the pretreatment method, and a desired method can be used according to the substrate to be used. Taking the case of subjecting a non-conductive material to a general electroless plating process as an example, a more specific embodiment will be described. For example, after arbitrarily degreasing and cleaning the surface to be treated of the substrate, an etching process is performed, and then it is brought into contact with a catalyst-imparting enhancement solution (conditioning). Next, after bringing the catalyst-imparting treatment solution into contact to impart a catalyst such as palladium, the catalyst is arbitrarily activated with an inorganic acid, a reducing agent, etc., and electroless nickel plating, electroless copper plating, electroless cobalt plating, etc. are performed.

[0060] The substrate after electroless plating may be further subjected to strike plating processes such as copper strike plating, nickel strike plating, silver strike plating, gold strike plating, etc.; general plating processes such as nickel plating, chromium plating, nickel-chromium plating, tin plating, tin-silver plating, copper plating, gold plating, silver plating, etc.

[0061] In addition, even when the substrate is a conductive material such as metal or conductive ceramic, if desired, the above-mentioned degreasing, etching, strike plating process, general plating process, etc. may be performed.

[0062] (Plating process operation) The arbitrarily pretreated object to be plated (substrate) is subjected to a plating process in the plating solution of the present invention. In the plating process, as described above, the liquid temperature is 10 to 90 °C, and the current density is 0.01 to 50 A / dm 2It is preferably set as such. More preferably, the liquid temperature is about 20 to 80°C, particularly about 25 to 70°C, and the current density is 0.1 to 20 A / dm 2 , particularly about 1 to 10 A / dm 2 . The plating time may be appropriately set according to the type of the target nickel-based alloy film, the liquid temperature during the treatment, and the current density, but it is preferably about 1 to 300 minutes, particularly about 3 to 120 minutes.

[0063] In addition, the appropriate pH of the plating solution during the plating treatment varies depending on the type of the target nickel-based alloy film and the composition of the plating solution used. For example, it may be about 0.5 to 12, particularly about 1 to 6. By performing the plating treatment under such conditions, a Ni-Cr-(Mo / W)-based alloy film excellent in the uniformity of composition and film thickness, such as a nickel-based alloy film having a composition like Hastelloy, can be easily formed. Also, during the plating treatment, it is preferable to perform liquid stirring by means of aeration, pump circulation, paddle stirring, etc.

[0064] (Post-treatment) The plated parts on which the nickel-based alloy film is formed as described above may of course be used as they are, but an electrolytic chemical conversion treatment film and / or an immersion chemical conversion treatment film may be further applied on the alloy film. The Ni-Cr-(Mo / W)-based alloy film generally has excellent heat resistance and corrosion resistance, but it is also possible to further enhance the corrosion resistance of the plated parts by the treatment film. There are no particular restrictions on the electrolytic chemical conversion treatment and the immersion chemical conversion treatment, and conventional treatment methods can be applied as desired. Examples include chromate treatment, wax treatment, treatment with solutions such as benzotriazole and triazine thiol, treatment with solutions of compounds having amino groups and imino groups, anodic oxidation treatment, and further heat treatment, etc., but it is not limited thereto.

[0065] ≪3. Plated parts≫ By the plating method of the present embodiment as described above, a Ni-Cr-(Mo / W)-based alloy film excellent in the uniformity of composition and film thickness can be formed on various substrates. Hereinafter, embodiments related to plated parts manufactured using the above plating solution and plated parts manufactured by the above plating method will be described.

[0066] The plated parts of the present embodiment exhibit excellent heat resistance and corrosion resistance derived from the Ni-Cr-(Mo / W)-based alloy film. Also, any material can be used as the substrate. Therefore, for example, a material with relatively good workability such as iron or stainless steel is used as the substrate, and it is possible to obtain plated parts that have a complex and fine shape, are excellent in heat resistance and corrosion resistance, and are low-cost. It is also possible to obtain a lightweight corrosion-resistant material by plating various shaped polymer materials, particularly heat-resistant polymer materials based on polyimide or the like. According to the present invention, various shaped industrial materials, automotive parts, building materials parts, home appliance parts, electronic parts, etc., which are excellent in heat resistance and corrosion resistance, are provided.

Example

[0067] Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to these descriptions in any way.

[0068] ≪Example 1≫ Sulfuric acid and an aqueous sodium hydroxide solution were added to a chemical solution (aqueous solution) having the following composition to adjust the pH to 2.5 to obtain a plating solution. In this plating solution, a copper disk (diameter 36 mm, one-sided area 0.1 dm 2 ) that had been acid-activated after degreasing was immersed, and using IrO2 / Ti as the anode, plating treatment was performed at 50 °C and 6 A / dm 2 for 6 minutes to obtain a plated part sample. The obtained sample exhibited a good appearance. For the disk sample, the contents (mass%) of Ni, Cr, and Mo, and the film thickness were measured at the central part and four points at the ends (four locations near each vertex of the square inscribed in the circle). The content and film thickness of each metal were measured by the FP method of fluorescent X-rays. The measurement results are shown in Table 1 described later.

[0069] [Composition of plating solution in Example 1] ·NiSO4·6H2O 0.02 mol / L ·Chromium basic sulfate 0.30 mol / L ·Na2MoO4·2H2O 0.02 mol / L ·Gluconic acid 0.30 mol / L ·Na2SO4 1.0 mol / L ·H3BO3 1.0 mol / L : Amount of complexing agent relative to total amount of metal ion source: 0.88 equivalent

[0070] ≪Example 2≫ The plating treatment time was set to 20 minutes, and the same operation as in Example 1 was performed. The measurement results are shown in Table 1.

[0071]

Table 1

[0072] In both Examples 1 and 2, nickel-based alloy films with slight variations in composition and film thickness depending on the measurement location and good appearance were obtained.

[0073] ≪Example 3≫ A copper plate (Halsell copper plate, 67 mm long × 100 mm wide) that had been acid-activated after degreasing was immersed as a cathode in a plating solution having the same composition as that used in Example 1, and a Halsell test was performed using IrO2 / Ti as the anode. The test was carried out in the same manner as in Example 1 by adjusting the pH of the plating solution to 2.5, setting the solution temperature to 50 °C, and applying a current value of 3 A for 5 minutes. The width (circumference: maximum 100 mm) of the region where the plating film was formed (ranging from the low current density side to the high current density side) and the average film thickness of the plating film at each current density based on the Halsell test are shown in Table 2 below, and the content rates of each metal element are shown in Table 3 below, respectively.

[0074] ≪Examples 4 to 6, Comparative Example 1≫ The same tests as in Example 3 were conducted, except that the amount of the complexing agent (gluconic acid) was 0.10 equivalent, 0.50 equivalent, or 1.88 equivalents (Examples 4 to 6), or 3.0 equivalents (Comparative Example 1) with respect to the total amount of the metal ion source. The results of the surface roughness and film thickness measurements are shown in Table 2, and the content rates of the respective metal elements in Example 6 are shown in Table 3.

[0075] ≪Comparative Examples 2 to 4≫ The same operations as in Example 3 were carried out, except that a chemical solution (aqueous solution) having the following composition was used and a Ni anode was used. In each plating solution, sulfuric acid and an aqueous sodium hydroxide solution were added to adjust the pH to 2.8. In Comparative Example 1, a larger amount of sulfuric acid and sodium hydroxide was added during pH adjustment compared to the comparative examples. Further, during the plating treatment, an air flow at a flow rate of 1 L / min was carried out only in Comparative Example 3. The results of the surface roughness and film thickness measurements are shown in Table 2, and the content rates of the respective metal elements in Comparative Example 2 are shown in Table 3.

[0076] [Composition of the Chemical Solution in Comparative Examples 2 to 4] ·NiCl2 0.042 mol / L ·CrCl3 0.19 mol / L ·Na2MoO4·2H2O 0.17 mol / L ·Sodium gluconate 0.16 mol / L ·Formic acid 0.78 mol / L ·Glycine 0.67 mol / L ·H3BO3 0.29 mol / L : Amount of the complexing agent with respect to the total amount of the metal ion source: 4.0 equivalents

[0077]

Table 2

[0078]

Table 3

[0079] In Examples 3 to 6 where the amount of complexing agent relative to the total amount of metal ion source was 0.10 to 1.88, the surrounding was 87 mm or more, and good results were obtained. In these examples, almost no burning or discoloration occurred. In particular, in Example 5 with 0.50 and Example 3 with 0.88, a plating film with a thickness generally exceeding 0.05 μm was formed. Also, in Examples 3 and 6, at a current density of 4 A / dm 2 or more, the chromium content in the plating film became 10 mass% or more. On the other hand, in Comparative Examples 1 to 4 where the amount of complexing agent relative to the total amount of metal ion source was as large as 3.0 to 4.0, the plating film thickness was generally thin. In particular, in Comparative Examples 2 to 4, the surrounding was as bad as 45 mm or less, and almost no plating film was formed at a current density of 5 A / dm 2 or less. In Comparative Examples 1 to 4, there was also a great tendency to cause burning and discoloration on the high current density side. In accordance with the present invention, it has become clear that by setting the amount of complexing agent within the range of 0.01 to 2 equivalents, a plating solution excellent in uniform electrodepositing property can be obtained.

[0080] ≪Example 7≫ A test similar to Example 2 was conducted except that a chemical solution (aqueous solution) having the following composition was used for preparing the plating solution. A Ni-Cr-W-based alloy (Ni:Cr:W ≒ 8:1:1) film with good appearance was formed.

[0081] [Composition of Chemical Solution in Example 7] ·NiSO4·6H2O 0.02 mol / L ·Basic chromium sulfate 0.30 mol / L ·Na2WO4·2H2O 0.02 mol / L ·Gluconic acid 0.30 mol / L ·Na2SO4 1.0 mol / L ·H3BO3 1.0 mol / L : Amount of complexing agent relative to the total amount of metal ion source: 0.88 equivalent

[0082] ≪Example 8≫ A test similar to Example 2 was conducted except that a chemical solution (aqueous solution) having the following composition was used for preparing the plating solution. A Ni-Cr-Mo-W-based alloy (Ni:Cr:Mo:W ≒ 5:1:1:3) film with good appearance was formed.

[0083] [Composition of the chemical solution in Example 8] ·NiSO4·6H2O 0.02 mol / L ·Chromium basic sulfate 0.30 mol / L ·Na2MoO4·2H2O 0.02 mol / L ·Na2WO4·2H2O 0.02 mol / L ·Gluconic acid 0.30 mol / L ·Na2SO4 1.0 mol / L ·H3BO3 1.0 mol / L : Amount of complexing agent relative to the total amount of metal ion source: 0.83 equivalent

[0084] <<Comparative Example 5>> The same operation as in Comparative Example 4 was performed except that NaCl was added as a conductive salt at a concentration of 1.00 mol / L. A good plating film was not formed, and the trailing value was 39 mm.

[0085] <<Reference Example 1>> A copper disc was plated in the same manner as in Example 2 (Ni:Cr:Mo ≒ 8:1:1), and the obtained plated sample was immersed in (1+1) hydrochloric acid for 3 minutes or (1+1) nitric acid for 0.5 minutes to conduct a corrosion test. The same operation was also performed on samples obtained by plating a shiny nickel plating, a hexavalent chromium plating, a Ni-Cr (8:2) alloy plating, and a Ni-Mo (5.5:4.5) alloy plating on the same copper disc, as well as the sample obtained in Example 7 (Ni:Cr:W ≒ 8:1:1) and the sample obtained in Example 8 (Ni:Cr:Mo:W ≒ 5:1:1:3). The appearance photographs after the test are shown in Fig. 1.

[0086] According to the present invention, the plated part sample having a Ni-Cr-(Mo / W) alloy film, unlike the plated part samples having a Ni-Cr alloy film or a Ni-Mo alloy film, showed almost no change in appearance after immersion in hydrochloric acid or after immersion in nitric acid. The high corrosion resistance of the Ni-Cr-(Mo / W) alloy film was demonstrated.

[0087] As described above, according to the present invention, there is provided a plating solution and a plating method capable of forming a Ni-Cr-(Mo / W) alloy film having excellent uniform electrodepositing properties with a more uniform composition and film thickness. According to the present invention, for example, a plating film of a nickel-based alloy having a composition such as Hastelloy can be formed on the surfaces of members of various shapes and materials with a uniform composition and film thickness, and it is also possible to obtain a plated part that is lightweight, low-cost, and excellent in heat resistance and corrosion resistance.

Claims

1. A plating solution containing a metal ion source including an ion source of nickel, chromium, and molybdenum and / or tungsten, and a complexing agent, wherein the amount of the complexing agent relative to the total amount of the metal ion source is 0.01 equivalent or more and 2 equivalents or less, and the plating solution is for forming a Ni—Cr—(Mo / W) alloy film.

2. The plating solution according to claim 1, further comprising a conductive salt.

3. The plating solution according to claim 2, wherein the conductive salt contains a sulfate.

4. The plating solution according to claim 1, further comprising a pH adjuster containing a hydroxide of an alkali metal.

5. The plating solution according to claim 1, wherein the complexing agent is at least one selected from the group consisting of carboxylic acids, carboxylates, hydroxycarboxylic acids, hydroxycarboxylates, amino acids, amino acid salts, and alcohols.

6. The plating solution according to claim 1, further comprising a pH buffer.

7. In the plating solution according to claim 1, the concentration of nickel is 0.001 to 0.5 mol / L in terms of element, the concentration of chromium is 0.01 to 1.5 mol / L in terms of element, and the total concentration of molybdenum and tungsten is in the range of 0.001 to 2.0 mol / L in terms of element.

8. A method for forming a Ni—Cr—(Mo / W) alloy film, comprising a step of plating using the plating solution according to any one of claims 1 to 7.

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