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 thickness.SOLUTION: Provided is a plating solution for forming a Ni-Cr-(Mo / W)-based alloy film, comprising: metal ion sources including ion sources of nickel, chromium, and molybdenum and / or tungsten; and one or more chemical species selected from the group consisting of ammonia, amines, and ammonium ions. Also provided is a method for forming a Ni-Cr-(Mo / W)-based alloy film, comprising a step of performing plating with the use of the plating solution. It is preferable that the plating solution further contains a complexing agent in an amount of 0.01 to 4 equivalents inclusive relative to the total amount of the metal ion sources.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 are hard and have the disadvantage of being 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 in formability can be solved, and cost reduction and weight reduction can be easily achieved. 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, respectively. 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] Japanese Patent Application Laid-Open No. 9-302496 [Patent Document 2] Japanese Patent Application Laid-Open No. 2005-082856 [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, it is difficult to uniformly electrodeposit a nickel-chromium-molybdenum alloy film. 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 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 film thickness in order to solve the above 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 containing one or more chemical species selected from the group consisting of ammonia, amines, and ammonium ions in the plating solution, a nickel-based alloy film can be uniformly electrodeposited, and thus the present invention has been completed.

[0010] That is, the present invention provides the following (1) to (10). (1) A plating solution for forming a Ni-Cr-(Mo / W) alloy film, comprising a metal ion source containing an ion source of nickel, chromium, and molybdenum and / or tungsten, and one or more chemical species selected from the group consisting of ammonia, amines, and ammonium ions. (2) The plating solution according to (1) above, further containing a complexing agent in an amount of 0.01 equivalent or more and 4 equivalents or less based on the total amount of the metal ion source. (3) The plating solution according to (1) or (2) above, wherein the chemical species is derived from one or more sources selected from the group consisting of aqueous ammonia, alkylamines, and ammonium salts. (4) The plating solution according to any one of (1) to (3) above, further containing a conductive salt. (5) The plating solution according to (4) above, wherein the conductive salt is a sulfate and / or a halide salt. (6) The plating solution according to any one of (1) to (5) above, further containing an organic acid salt and / or an inorganic acid salt. (7) The plating solution according to any one of (2) to (6) above, wherein the complexing agent is one or more selected from the group consisting of carboxylic acids, carboxylates, hydroxycarboxylic acids, hydroxycarboxylates, amino acids, amino acid salts, and alcohols. (8) The plating solution according to any one of (1) to (7) above, further containing a pH buffer. (9) The plating solution according to any one of (1) to (8) above, wherein the concentration of nickel is in the range of 0.001 to 0.5 mol / L in terms of elemental conversion, the concentration of chromium is in the range of 0.01 to 1.5 mol / L in terms of elemental conversion, and the total concentration of molybdenum and tungsten is in the range of 0.001 to 2.0 mol / L in terms of elemental conversion. (10) A method for forming a Ni-Cr-(Mo / W) alloy film, including a step of plating using the plating solution according to any one of (1) to (9) above.

Advantages of the Invention

[0011] The plating solution of the present invention is excellent in uniform electrodepositing property, and according to the plating solution and method of the present invention, a Ni-Cr-(Mo / W) alloy film can be uniformly electrodeposited without large variations in film thickness and the like.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Modes 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 the present embodiment is a plating solution for forming a Ni - Cr - (Mo / W) - based alloy film containing a metal ion source containing nickel, chromium, and an ion source of molybdenum and / or tungsten, and containing one or more chemical species selected from the group consisting of ammonia, amine, and ammonium ions.

[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 the present embodiment. It is also possible to use a plurality of ion sources of the same metal, for example, a chromium salt and a chromate, in combination. In addition, salts such as nickel molybdate can also 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, from the viewpoint of further enhancing the uniform electrodepositing property of the plating solution, it is preferable to use a metal salt or a metal acid salt that is not a complex as the metal ion source.

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

[0018] The metal ion source may further contain ion sources of other metals, for example, 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 etc. in a Ni-Cr-Mo-Fe system, and further nickel-based alloy films having compositions such as INCONEL, INCOLOY, Waspaloy, DASALOY (registered trademark) can also be formed. If desired, phosphates, silicates, etc. can be used in combination to obtain a plating solution for a nickel-based alloy film containing phosphorus (P) and silicon (Si). According to the plating solution of the present embodiment, it may also be possible to form an alloy film having a composition that cannot be made by metallurgical techniques.

[0019] (Concentration of metal ion source) In the plating solution of the present embodiment, the concentration of the metal ion source can be arbitrarily set according to the type of the target plating film, the plating treatment conditions, and the like. For example, the concentration of nickel can be set to 0.001 to 0.5 mol / L in terms of elemental conversion, the concentration of chromium can be set to 0.01 to 1.5 mol / L in terms of elemental conversion, and the total concentration of molybdenum and tungsten can be set to 0.001 to 2.0 mol / L in terms of elemental conversion.

[0020] Alternatively, the concentration settings of these metal components are all such that 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, and the molybdenum concentration is 0.001 to 2.0 mol / L, particularly 0.01 to 1.0 mol / L, in terms of elemental conversion. If desired, tungsten can be added in place of or in addition to molybdenum at a concentration of about 0.001 to 2.0 mol / L, particularly 0.01 to 1.0 mol / L.

[0021] Incidentally, the total amount of the metal ion source related to the concentration of each of the above metal components will also be described here. In the present embodiment, the "total amount of the metal ion source" 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.

[0022] <Species such as ammonia> The plating solution of the present embodiment contains, together with a metal ion source, one or more chemical species selected from the group consisting of ammonia, amines, and ammonium ions. With a plating solution containing such chemical species, excellent uniform electrodepositing properties are achieved, and it becomes possible to form a nickel-based alloy film with a more uniform film thickness. Note that these effects are achieved regardless of whether the above chemical species are derived from which component in the plating solution, for example, whether they are derived from a pH adjuster or a conductive salt.

[0023] In the present embodiment, the above chemical species may be derived from one or more sources selected from the group consisting of, for example, aqueous ammonia, alkylamines, and ammonium salts. There is no particular limitation on the type of the source. The plating solution of the present embodiment can be obtained, for example, by blending a metal ion source and an additive containing ammonia, amines, and / or ammonium ions. For example, ammonium chromate, ammonium molybdate, etc. may be used as the metal ion source, or a pH adjuster or a conductive salt containing ammonia, amines, or ammonium salts may be added. Alternatively, a plating solution can be prepared by using sources of metal ions, pH adjusters, and conductive salts that do not contain ammonia, amines, and ammonium ions, and separately blending other components containing ammonia, amines, and / or ammonium ions.

[0024] (Aqueous ammonia) When ammonia is contained in the plating solution of the present embodiment, it is preferable to use aqueous ammonia as the source. Since aqueous ammonia is a liquid at room temperature, it is easy to handle and there is little risk of reducing the production efficiency of the plating solution. Also, since various commercially available products are available, it is suitable from the viewpoint of cost reduction. There is no particular limitation on the aqueous ammonia that can be used, and for example, general-purpose products having an ammonia concentration of 20 to 40% by mass, particularly about 25 to 35% by mass can be used.

[0025] (Amine) There is no particular limitation on the amine used in this embodiment. Examples include alkylamines such as monomethylamine, monoethylamine, monopropylamine, monobutylamine, monohexylamine, monooctylamine, dimethylamine, diethylamine, dipropylamine, dibutylamine, dihexylamine, dioctylamine, trimethylamine, triethylamine, tripropylamine, tributylamine, trihexylamine, trioctylamine, methyldiethylamine, ethyldimethylamine, piperidine, etc.; aromatic amines such as pyridine, methylpyridine, ethylpyridine, dimethylpyridine, imidazole, bipyridine, etc.; hydroxy group-containing amines such as monomethanolamine, monoethanolamine, trimethanolamine, triethanolamine, etc.; and further DBU, etc., but not limited thereto.

[0026] From the viewpoints of handleability and cost, it is preferable to use alkylamines, particularly trialkylamines such as trimethylamine and triethylamine. A plurality of types of amines can also be used in combination. Further, as a source of the amine, it is also possible to use a mixture containing ammonia or ammonium ions.

[0027] (Ammonium ion) There is no particular limitation on the type of ammonium ion. Examples include the ammonium ion in the narrow sense represented by the chemical formula of NH4 + In addition to the ammonium ion in the narrow sense represented by the chemical formula of NH4; alkylammonium ions such as tetramethylammonium ion, tetraethylammonium ion, tetrapropylammonium ion, tetrabutylammonium ion, piperidinium ion, etc.; aromatic ammonium ions such as pyridinium ion, imidazolium ion, etc., but not limited thereto.

[0028] These ammonium ions can be obtained, for example, by dissolving an ammonium salt or a base having, as a counter anion, a hydroxy anion, a halogen ion such as chlorine, an inorganic ion such as a sulfate ion, a nitrate ion, a phosphate ion, or an organic ion such as an acetate anion in a plating solution. Preferably, ammonium-based compounds in a narrow sense such as ammonium hydroxide (NH4OH), ammonium sulfate, ammonium phosphate, ammonium acetate; tetramethylammonium hydroxide, tetrabutylammonium hydroxide, and their sulfate salts, halide salts, etc., particularly ammonium hydroxide and / or ammonium sulfate are used. These ammonium-based compounds are highly water-soluble and low-cost, and thus are suitable as raw materials for plating solutions.

[0029] Ammonium ions can also be formed by adding ammonia or an amine to the plating solution. In this embodiment, there is no particular limitation on the pH of the plating solution, but in order to further improve the uniform electrodeposition property, the pH of the plating solution is preferably about 0.5 to 12, for example, about 0.5 to 10, particularly about 0.5 to 7.5, more preferably about 1.0 to 6.0, and especially preferably about 2.0 to 4.0. When ammonia or an amine is blended as a pH adjuster, for example, into such a plating solution under acidic conditions, at least a part of it will naturally become ammonium ions. In this embodiment, the plating solution preferably contains both ammonia and / or an amine and ammonium ions, particularly ammonia and ammonium ions in a narrow sense, as the above chemical species.

[0030] In the plating solution of this embodiment, the concentration of the above chemical species is preferably 0.01 mol / L or more, more preferably 0.05 mol / L or more, and even more preferably 0.1 mol / L or more. For example, it is preferably about 0.01 to 10.0 mol / L, particularly about 0.05 to 5.0 mol / L, and especially preferably about 0.1 to 3.0 mol / L. At such concentrations, it becomes easier to form a nickel-based alloy film with a more uniform composition and film thickness.

[0031] Although the present invention is not limited by a specific theory, it is conceivable that these chemical species may function to suppress fluctuations in ionic concentration and pH in the plating solution. Due to the presence of these chemical species, changes in the liquid state during the plating operation may be suppressed, and as a result, the electrodepositing property may be improved.

[0032] <Solvent> In the plating solution of the present embodiment, the solvent containing the metal ion source and the above chemical species is preferably water, but alcohols such as methanol and ethanol; ethers such as tetrahydrofuran (THF), dioxane, and various glymes; carbonates 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 metal salts and chemical species used, an organic solvent may also be used as the main solvent.

[0033] <Additive> In the plating solution of the present embodiment, various additives such as a complexing agent, a conductivity-imparting agent such as 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 together with the metal ion source and the above chemical species. As described above, ammonia, amine, and / or ammonium ion may be added as a conductive salt or a pH adjuster. For example, in a plating solution containing ammonium sulfate as a conductive salt or aqueous ammonia as a pH adjuster, these additives are already included, but other types of conductive salts and pH adjusters may be further added in addition thereto.

[0034] Among the above-described additives, the blending of a complexing agent, a conductive salt, a pH adjuster, and a pH buffer can further improve the uniform electrodepositing property of the plating solution. In particular, the complexing agent is an additive that can also contribute to the improvement of the electrodepositing property. Some of these additives will be described below.

[0035] <Complexing agent> The plating solution of the present embodiment preferably contains a complexing agent together with a metal ion source and the above chemical species. In the present embodiment, the complexing agent may be of any type, and conventional ones can be used. Incidentally, although ammonia and amines mentioned above can form complexes with transition metals such as nickel and chromium depending on conditions, they cannot form complexes under various conditions including, for example, acidic conditions. Therefore, in the present embodiment, the above chemical species are treated as not falling within the category of complexing agents.

[0036] Specifically, examples of the complexing agent 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, glucoheptanolactone, etc., but are not limited thereto. It is also possible to use a combination of multiple types of complexing agents.

[0037] 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 is also possible to further improve the uniform electrodeposition property. Among these in particular, 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.

[0038] (Carboxylic acids and their salts) Suitable carboxylic acids as complexing agents include aliphatic monocarboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, hexanoic acid; aliphatic dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, maleic acid, malic acid; aliphatic tricarboxylic acids such as aconitic acid; aromatic carboxylic acids such as benzoic acid, salicylic acid, phthalic acid, cinnamic acid, etc. Examples of carboxylates include their sodium salts, potassium salts, ammonium salts, etc. In addition, salts of carboxylic acids having a plurality of carboxy groups may be those in which only some of the carboxy groups form salts, double salts, such as sodium hydrogen oxalate or potassium sodium oxalate, etc.

[0039] (Hydroxycarboxylic acids and their salts) Suitable hydroxycarboxylic acids 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, sodium hydrogen tartrate or potassium sodium tartrate, etc. may be used.

[0040] (Amino acids and their salts) Suitable amino acids (aminocarboxylic acids) 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, etc. Examples of amino acid salts include their sodium salts, potassium salts, ammonium salts, etc.

[0041] (Alcohols) Examples of alcohols suitable as complexing agents include glycols such as ethylene glycol, propylene glycol, and diethylene glycol.

[0042] (Amount of complexing agent) In the plating solution of this embodiment, the amount of the complexing agent relative to the total amount of the metal ion source is preferably 0.01 equivalent or more and 4 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 4 equivalents, the uniform electrodepositing property of the plating solution can be further improved, and a nickel-based alloy film with more uniform film thickness and the like can be formed.

[0043] Generally, in alloy plating, since a plurality of metals with different deposition potentials are used, a large amount of a complexing agent more than the amount of the metal ion source is used in order to form a desired type of alloy film with a uniform composition. In the formation of a plating film from the plating solution containing the above chemical species this time, an unexpected effect that the electrodepositing property of the plating solution is further improved has been exhibited by setting the amount of the complexing agent relative to the total amount of the metal ion source to a relatively small amount of 0.01 to 4 equivalents.

[0044] 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. Incidentally, the "total amount of the metal ion source" is the total molar amount of all the ion sources for the metal constituting the target plating film as described above, and is an amount based on the metal element. For example, when 0.1 mol of Cr2(SO4)3 is contained in the plating solution, the amount of the chromium ion source is calculated as 0.2 mol.

[0045] In the plating solution of the present embodiment, as described above, it is preferable that the amount of the complexing agent with respect to the total amount of the metal ion source, that is, the molar ratio of the complexing agent amount / total metal ion source amount, is 0.01 equivalent or more and 4 equivalents or less. More preferably, the molar ratio of the complexing agent amount / total metal ion source amount is, for example, 0.05 equivalent or more, still more preferably 0.10 equivalent or more, even more preferably 0.20 equivalent or more, still more preferably 0.30 equivalent or more, and particularly preferably 0.40 equivalent or more. The same molar ratio is also preferably 3.0 equivalents or less, more preferably 2.0 equivalents or less, particularly preferably 1.0 equivalent or less, and further set to 0.8 equivalent or less, or 0.6 equivalent or less, and may be, for example, 0.10 to 2.0 equivalents, especially 0.20 to 1.5 equivalents, further 0.30 to 1.0 equivalents, and particularly 0.40 to 0.90 equivalents.

[0046] By appropriately selecting the molar ratio of the complexing agent amount / total metal ion source amount within the range of 0.01 to 4 according to the type of the target plating film, the type of the complexing agent, etc., the uniform electrodepositing property can be further improved. 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.

[0047] (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 these inorganic salts are preferable. If the plating solution contains a sulfate or an ammonium salt as the conductive salt, the precipitation of the metal for forming the target film is promoted in a well-balanced manner, and it becomes easier to form an alloy plating with a more uniform composition and film thickness. Also, when the conductive salt is an ammonium salt, the conductive salt also serves as a source of the above chemical species.

[0048] Specific examples of suitable conductive salts include, but are not limited to, sodium sulfate, potassium sulfate, ammonium sulfate, ammonium chloride, ammonium bromide, ammonium nitrate, ammonium phosphate, etc. Among them, sodium sulfate, potassium sulfate, and ammonium sulfate are particularly preferred, and ammonium sulfate is especially preferred.

[0049] 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, a concentration of 0.1 to 3 mol / L, particularly about 0.25 to 2 mol / L may be used, but it is not limited to such a range.

[0050] (pH adjuster) In order to further improve the uniform electrodepositing property, the plating solution of this embodiment contains a pH adjuster, and the pH may be adjusted to a region suitable for nickel-based alloy plating, for example, about 0.5 to 12, particularly about 0.5 to 10, more preferably about 0.5 to 7.5, still more preferably about 1.0 to 6.0, and particularly preferably about 2.0 to 4.0.

[0051] The pH adjuster is particularly useful when using a complexing agent. 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 the plating solution 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.

[0052] There is no particular limitation on the pH adjuster added to the plating solution of this embodiment, and various acids and / or bases can be used according to the pH during the intended plating treatment or aging. Here, when using a pH adjuster containing sulfuric acid as an acid, or when using a pH adjuster containing an alkali metal hydroxide, ammonia, and / or an amine as a base, there is an advantage that the conductivity of the plating solution is improved, which is preferable. When the pH adjuster contains ammonia, an amine, and / or an ammonium ion, the pH adjuster also serves as a source of these chemical species.

[0053] (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. The pH buffer can be regarded as a kind of pH adjuster in a broad sense, but here it is treated as a component different from the pH adjuster in a narrow sense. There is no particular limitation on the type of the 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. When the pH buffer contains ammonia, amine, and / or ammonium ion, the pH buffer also serves as a source of the above chemical species.

[0054] (Hydrogen generation inhibitor) The plating solution of the present embodiment may also contain a hydrogen generation inhibitor. By including a hydrogen generation inhibitor in the plating solution, it becomes easy to suppress a decrease in the current efficiency during the plating process. Further, as a result of suppressing the generation of hydrogen gas at the cathode, it becomes easy to prevent burning and hydrogen embrittlement of the plating film. Note that burning is 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.

[0055] 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 above-mentioned complexing agent or pH buffer. 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 also possible to exhibit all the functions of complex formation, pH adjustment, and hydrogen generation suppression.

[0056] (Brightener) The plating solution of this embodiment may contain a brightener. The brightener not only imparts luster to the plating film, but may also promote the deposition of metal in the recesses and exhibit the function of flattening the plating surface. There is no particular limitation on the type of brightener, and various aldehydes, triazines, imidazoles, indoles, quinolines, 2-vinylpyridines, 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.

[0057] (Surfactant) There is no particular limitation on the surfactant, and a desired one can be selected from ordinary anionic surfactants, cationic surfactants, nonionic surfactants, amphoteric surfactants, etc. When containing a surfactant, its concentration is preferably about 1 mg / L to 50 g / L, particularly about 5 mg / L to 10 g / L.

[0058] (Antioxidant) The antioxidant is used to prevent the oxidation of metal salts. Examples of the antioxidant include hypophosphorous acids, ascorbic acid, phenolsulfonic acid, cresolsulfonic acid, hydroquinonesulfonic acid, hydroquinone, α or β-naphthol, catechol, resorcinol, phloroglucin, hydrazine, phenolsulfonic acid, catecholsulfonic acid, hydroxybenzenesulfonic acid, naphtholsulfonic acid, and their salts, etc., 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.

[0059] Some representative additives have been described above. However, the plating solution of the present invention may contain various other additives in addition to these. Also, one or two kinds of certain additives can be used also as a functional agent that brings about a plurality of effects. As described above, some pH adjusters and conductive salts can also be a source of the above chemical species. In addition to these, for example, one or two kinds of inorganic acids such as sulfuric acid and phosphoric acid, organic acids such as carboxylic acid and sulfonic acid, bases, and their salts may be used to exhibit various functions such as imparting conductivity, adjusting pH, buffering action, and suppressing hydrogen generation. The present invention also includes a plating solution for forming a Ni-Cr-(Mo / W) based alloy film containing an inorganic acid salt and / or an organic acid salt.

[0060] <Preparation of Plating Solution> The plating solution of the present embodiment can be prepared from the above components using a conventional method, and the details can be appropriately determined in consideration of the composition and blending amount of each component. In particular, when the plating solution contains a complexing agent, etc., pH adjustment and "aging" treatment may be performed before use.

[0061] ≪2. Method for Forming Alloy Film≫ By performing plating treatment using the plating solution of the various embodiments as described above, a desired Ni-Cr-(Mo / W) based alloy film can be formed on various substrates. Therefore, as a method for forming a Ni-Cr-(Mo / W) based alloy film, it can be defined as a method including a step of performing plating treatment using the above-described plating solution. According to such a method, a nickel-based alloy film excellent in uniform electrodeposition property and having a uniform film thickness can be formed.

[0062] There are no particular restrictions on the method and conditions of the plating treatment, and for example, general electroplating can be performed under conventional conditions according to the type of the target nickel-based alloy film and the substrate to be plated.

[0063] Specifically, the temperature of the plating solution can be about 10 to 90°C. Also, the current density can be about 0.01 to 50 A / dm 2 degree.

[0064] <Overview of plating process> A nickel-based alloy film can be formed, for example, by immersing an object to be plated as a cathode in the plating solution of the present invention together with an anode and passing an electric current. Here, if the liquid temperature is 10 °C or higher and the current density is 0.01 A / dm 2 or higher, it becomes easier to form a nickel-based alloy film in a relatively short time. If the liquid temperature is 90 °C or lower, changes in concentration and the like due to evaporation or boiling of the plating solution are suppressed, and as a result, it becomes easier to form a nickel-based alloy film with more uniform composition and film thickness. Also, if the current density is 50 A / dm 2 or lower, it becomes easier to suppress the occurrence of defects such as burning in the generated alloy film. Incidentally, the plating solution in the plating bath may be referred to as the "plating bath" in some cases, but in this embodiment, both are regarded as the same and referred to as the "plating solution".

[0065] (Object to be plated) Here, the object to be plated in this embodiment may be any material as long as it has conductivity. Of course, various metal materials and conductive ceramic materials, as well as non-conductive ceramics, glass, carbon materials, resins, rubbers, wood, etc. (non-conductive materials), can be used by applying electroless plating or metal vapor deposition to make them conductive. 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.

[0066] 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 the present embodiment can be particularly effective. For example, by forming a film of Ni-Cr-(Mo / W) alloy on a substrate made of iron or stainless steel, or a material obtained by subjecting these substrates 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 the present embodiment. The polymer material treated by the plating method of the present embodiment can be utilized as a lightweight corrosion-resistant material.

[0067] (Anode) There are no particular restrictions on the anode used for the plating treatment either. 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 bath 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 a more homogeneous alloy film.

[0068] <The actual plating process> Hereinafter, the plating treatment for forming a nickel-based alloy film on various conductive or non-conductive substrates will be described more specifically.

[0069] (Pretreatment) Prior to the plating treatment of the present embodiment, the base material to be plated may be subjected to pretreatment, such as degreasing or acid activation treatment. In particular, when plating non-conductive materials such as common ceramics and 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.

[0070] There is no particular limitation on the pretreatment method, and a desired method can be used according to the base material to be used. Taking the case of subjecting a non-conductive material to a general electroless plating treatment as an example, a more specific embodiment will be described. For example, after arbitrarily degreasing and cleaning the surface to be treated of the base material, an etching treatment is performed, and then it is brought into contact with a catalyst-imparting enhancing 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.

[0071] After electroless plating, the base material may be further subjected to strike plating treatments such as copper strike plating, nickel strike plating, silver strike plating, gold strike plating, etc.; general plating treatments such as nickel plating, chromium plating, nickel-chromium plating, tin plating, tin-silver plating, copper plating, gold plating, silver plating, etc.

[0072] In addition, even when the base material is a conductive material such as metal or conductive ceramic, if desired, the above-mentioned degreasing, etching, strike plating treatment, general plating treatment, etc. may be performed.

[0073] (Plating treatment operation) The optionally pretreated object to be plated (base material) is subjected to plating treatment in the plating solution of the present invention. In the plating treatment, as described above, the liquid temperature is 10 to 90 °C, and the current density is 0.01 to 50 A / dm 2 It is preferably set as such. More preferably, the liquid temperature is 20 to 80 °C, particularly about 25 to 70 °C, and the current density is 0.1 to 20 A / dm 2 , particularly 1 to 10 A / dm 2It is advisable to set it to such a level. 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. Generally, it is preferably about 1 to 300 minutes, particularly about 3 to 120 minutes.

[0074] 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, or about 0.5 to 10. Among them, it is preferably about 0.5 to 7.5, more preferably about 1.0 to 6.0, and particularly preferably about 2.0 to 4.0. 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. Further, during the plating treatment, it is preferable to perform liquid stirring by means of aeration, pump circulation, paddle stirring, etc.

[0075] (Post-treatment) The plated parts on which the nickel-based alloy film is formed as described above may be used as they are, or an electrolytic chemical conversion treatment film and / or an immersion chemical conversion treatment film may be further provided 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 a solution such as benzotriazole or triazine thiol, treatment with a solution of a compound having an amino group or an imino group, anodic oxidation treatment, and further heat treatment, etc., but are not limited thereto.

[0076] ≪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 film thickness and the like can be formed on various substrates. Hereinafter, embodiments related to the plated parts manufactured using the above plating solution and the plated parts manufactured by the above plating method will be described.

[0077] The plated parts of this embodiment exhibit excellent heat resistance and corrosion resistance derived from the Ni-Cr-(Mo / W) alloy coating. Also, any material can be used as the base material. Therefore, for example, a material with relatively good workability such as iron or stainless steel can be used as the base material to make 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 make a lightweight corrosion-resistant material by plating various shaped polymer materials, especially heat-resistant polymer materials based on polyimide or the like. According to the present invention, various plated parts such as industrial materials, automotive parts, building materials parts, household electrical appliance parts, and electronic parts of various shapes, which are excellent in heat resistance and corrosion resistance, are provided.

Example

[0078] 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.

[0079] ≪Example 1≫ Sulfuric acid and aqueous ammonia were added to a chemical solution (aqueous solution) having the following composition to adjust the pH to 2.5 to obtain a plating solution (concentration of ammonia and / or ammonium ions: 0.25 mol / L). A copper plate (Halsell copper plate with a length of 67 mm and a width of 100 mm) that had been acid-activated after degreasing was immersed as a cathode in this plating solution, and a Halsell test was performed using IrO2 / Ti as the anode. The test was carried out at a liquid temperature of 50°C and a current value of 3 A for 5 minutes. The appearance photograph figure after the test is shown in Fig. 1, the width (circumference: 100 mm is the maximum) 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 1 below, and the content of each metal element is shown in Table 2 below.

[0080] [Composition of the chemical 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 equivalents

[0081] <<Examples 2 - 3>> The same operations as in Example 1 were carried out except that the amount of the complexing agent relative to the total amount of the metal ion source was 3.0 equivalents (Example 2) or 4.0 equivalents (Example 3). The appearance photograph figure after the test of Example 2 is shown in Fig. 2. The average film thickness of the plating film around and at each current density of Examples 2 and 3 is shown in Table 1 below, and the content rate of each metal element is shown in Table 2 below.

[0082] <<Comparative Example 1>> The same operations as in Example 2 were carried out except that an aqueous sodium hydroxide solution was used instead of aqueous ammonia. The appearance photograph figure after the test is shown in Fig. 3, the average film thickness of the plating film around and at each current density is shown in Table 1 below, and the content rate of each metal element is shown in Table 2 below, respectively.

[0083] <<Example 4>> The same operations as in Example 1 were carried out except that a chemical solution (aqueous solution) having the following composition was used. The results of around and film thickness measurement are shown in Table 1 below, and the content rate of each metal element is shown in Table 2 below, respectively.

[0084] [Composition of Chemical Solution in Example 4] ·NiSO4·6H2O 0.02 mol / L ·Chromic Sulfate Basic 0.30 mol / L ·Na2MoO4·2H2O 0.02 mol / L ·Gluconic Acid 0.30 mol / L ·NaCl 1.0 mol / L ·H3BO3 1.0 mol / L : Amount of complexing agent relative to total amount of metal ion source: 0.88 equivalents

[0085] <<Comparative Example 2>> An operation almost the same as that in Comparative Example 1 was carried out, except that a chemical solution (aqueous solution) having the following composition was used and a Ni anode was used. The plating solution was adjusted to pH 2.8 by adding sulfuric acid and an aqueous sodium hydroxide solution. The appearance photo figure after the test is shown in Figure 4, the results of the circumferential and film thickness measurements are shown in Table 1 below, and the content rates of each metal element are shown in Table 2 below, respectively.

[0086] [Composition of Chemical Solution in Comparative Example 2] ·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 ·NaCl 1.0 mol / L : Amount of Complexing Agent with Respect to Total Amount of Metal Ion Sources: 4.0 Equivalents

[0087] ≪Example 5≫ An operation the same as that in Example 1 was carried out, except that a chemical solution (aqueous solution) having the following composition was used and the pH was adjusted to 2.5 using an aqueous sodium hydroxide solution together with sulfuric acid. That is, the plating solution of this example contains ammonium ions derived from a conductive salt rather than from a pH adjuster. The results of the circumferential and film thickness measurements are shown in Table 1, and the content rates of each metal element are shown in Table 2, respectively.

[0088] [Composition of Chemical Solution in Example 5] ·NiSO4·6H2O 0.02 mol / L ·Basic Chromium Sulfate 0.30 mol / L ·Na2MoO4·2H2O 0.02 mol / L ·Gluconic Acid 0.30 mol / L ·(NH3)2SO4 1.0 mol / L ·H3BO3 1.0 mol / L : Amount of Complexing Agent with Respect to Total Amount of Metal Ion Sources: 0.88 Equivalents

[0089]

Table 1

[0090]

Table 2

[0091] In Examples 1 to 5 using a plating solution containing ammonia or ammonium ions according to the present invention, the periphery was 80 mm or more, indicating good uniform electrodeposition properties. In addition, a plating film with almost no burning or discoloration was obtained. Generally, the suppression of burning and discoloration is considered more important than ensuring the film thickness. Even in Comparative Example 1 without ammonia or ammonium ions, the periphery was 88 mm, which was good, but burning and discoloration were noticeable on the high current density side. In Comparative Example 2, the periphery was 39 mm, which was extremely poor, and burning and discoloration were observed on the low current density side. Moreover, the amount of Mo deposition was small even on the high current density side, and the obtained plating film could hardly be said to be a Ni-Cr-Mo based alloy film.

[0092] In the examples of the present application, the difference in film thickness due to the difference in current density was also small. Considering that the film thickness differed greatly depending on the current density in Comparative Example 2, it is suggested that the plating solution of the present invention can reduce the film thickness variation due to plating conditions. This tendency was particularly remarkable in Examples 1, 4, and 5 where the complexing agent equivalent was 1 or less. In Examples 1, 4, and 5, a periphery amount of nearly 100 mm was also measured, indicating that particularly excellent uniform electrodeposition properties can be exhibited when the complexing agent equivalent is 2 or less, for example, 1 or less.

[0093] As described above, according to the present invention, there are provided a plating solution and a plating method that are excellent in uniform electrodeposition properties and can form a Ni-Cr-(Mo / W) based alloy film with a more uniform 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 plating parts that are lightweight, low-cost, and excellent in heat resistance and corrosion resistance can be obtained.

Claims

1. A plating solution for forming a Ni-Cr-(Mo / W) alloy film, comprising a metal ion source containing an ion source of nickel, chromium, and molybdenum and / or tungsten, and one or more chemical species selected from the group consisting of ammonia, amines, and ammonium ions.

2. The plating solution according to claim 1, further comprising a complexing agent in an amount of 0.01 equivalent or more and 4 equivalents or less based on the total amount of the metal ion source.

3. The plating solution according to claim 1 or 2, wherein the chemical species is derived from one or more sources selected from the group consisting of aqueous ammonia, alkylamines, and ammonium salts.

4. The plating solution according to claim 1 or 2, further containing a conductive salt.

5. The plating solution according to claim 4, wherein the conductive salt is a sulfate and / or a halide salt.

6. The plating solution according to claim 1 or 2, further containing an organic acid salt and / or an inorganic acid salt.

7. The plating solution according to claim 2, wherein the complexing agent is one or more selected from the group consisting of carboxylic acids, carboxylates, hydroxycarboxylic acids, hydroxycarboxylates, amino acids, amino acid salts, and alcohols.

8. The plating solution according to claim 1 or 2, further containing a pH buffer.

9. The plating solution according to claim 1 or 2, wherein the concentration of nickel is in the range of 0.001 to 0.5 mol / L in terms of element, the concentration of chromium is in the range of 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.

10. A method for forming a Ni-Cr-(Mo / W) alloy film, comprising a step of plating using the plating solution according to claim 1 or 2.

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