JP4271399B2 - Method for forming Re film by electrolytic plating using Cr (III) -containing bath - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for forming a Re film used for a corrosion-resistant film for a high-temperature device member.
[0002]
[Prior art]
Ni-base superalloy base materials used for jet engines and gas turbine blades are strongly required to have oxidation resistance and corrosion resistance. For this reason, diffusion treatment of Al or the like is performed on the surface, for example, an Al ₂ O ₃ film is applied to obtain high-temperature oxidation resistance. However, its performance is not sufficient, and means such as providing a diffusion barrier using Pt or the like on the substrate have been developed. When Re is used as the diffusion barrier layer, the high temperature corrosion resistance can be improved. Re is excellent in thermal shock resistance and is used as a high-temperature member such as various combustors such as a rocket engine combustor and a high-temperature nozzle. Until now, the following methods are known as methods for forming the Re film and the Re alloy film.
[0003]
(1) Sputtering method or physical vapor deposition method While film thickness and composition are easy to control, (1) there are many restrictions on the size and shape of the substrate, (2) the apparatus is large and the operation is complicated, 3) There are problems such as the formation of a film with many defects and cracks.
(2) Thermal spraying method (1) A film with many defects is formed, (2) It is not suitable for forming a thin film (less than 10 μm), (3) The yield is poor and uneconomical. .
(3) Electroplating method for Re alloy
Ni-Cr-Re with a maximum Re content of 50% by weight (lower percentage in atomic composition) and Re-Ni alloys for electrical contacts with a maximum Re content of 85% by weight (63 atomic%) Although plating is known, the Re content is low.
[0004]
[Problems to be solved by the invention]
The present invention makes it possible to construct complex shapes that cannot be solved by sputtering or physical vapor deposition, etc., thin film construction that cannot be solved by thermal spraying, and electroplating Re at a lower cost and easier than both. A method of forming is provided.
[0005]
[Means for Solving the Problems]
The inventors have hardly electrolytically deposited Re from a bath containing only perrhenate ions as transition metal ions, but from a bath in which perrhenate ions and Cr ³⁺ ions coexist, perrhenate ions in the bath It was found that by controlling the concentration ratio of the other metal ions and the pH of the bath, almost no Cr was electrodeposited and only Re having a purity of 98 atomic% or more was electrodeposited.
[0006]
That is, the present invention contains perrhenate ions 0.001 mol / l to 2.0 mol / l, Cr ³⁺ ions 0.01 mol / l to 10.0 mol / l, and the perrhenate ions in the plating bath. of, and the molar ratio of Cr ³⁺ ions is 0.1 or more, more total metal ion concentration of 0.1 to 15.0 organic acid equivalent or less of a concentration relative to contain the following bromide 0.0001 mol / l or more 5.0 mol / l , pH is 0-5, the liquid temperature, using a plating bath comprising an aqueous solution is 10 to 80 ° C., Re is less than 98% by atomic composition by electrolysis, a film that the rest and Cr and inevitable impurities It is an electrolytic plating method of Re characterized in that it is formed, whereby it becomes possible to electrolytically deposit 98% or more of purity Re.
[0007]
If the perrhenate ion is less than 0.001 mol / l, the Re concentration during plating is low, and if it is more than 2.0 mol / l, an insoluble material is generated. Further, when the Cr ³⁺ ion concentration is less than 0.01 mol / l, the electrolytic deposition efficiency of Re is remarkably low, and when it exceeds 10.0 mol / l, an insoluble material is generated. Therefore, the perrhenate ion was limited to 0.001 mol / l or more and 2.0 mol / l or less, and the Cr ³⁺ ion concentration was limited to 0.001 mol / l or more and 10.0 mol / l or less.
[0008]
The pH of the plating bath is preferably 0 to 5, and the temperature at which plating is performed is preferably 10 to 80 ° C. With these, plating with high covering power and uniform composition can be obtained. If the pH is less than 0, the covering power of the plating is reduced, and if it is more than 5, the insoluble material is large and the fluidity of the liquid is impaired, and the Re concentration in the film is lowered. In addition, when the temperature of the solution at which plating is performed is lower than 10 ° C., the electrolytic deposition efficiency is remarkably reduced, and when it is higher than 80 ° C., the covering power is reduced. Therefore, the pH of the bath was limited to 0-5, and the temperature of the solution for plating was limited to 10-80 ° C. More preferably, the pH of the bath is 2 to 5, and the temperature at which plating is performed is 20 to 40 ° C.
[0009]
With a film in which Re is 98% or more with the atomic composition formed by the method of the present invention, and the remainder is Cr and unavoidable impurities, the material to be plated can be given a function according to the type and purpose of the substrate. It becomes possible.
[0010]
Moreover, this invention is said electrolytic plating method characterized by the plating bath containing an organic acid, By this, it becomes possible to obtain the film | membrane of a more stable composition. By specifying the type and concentration of the organic acid, a film having a more stable composition can be obtained. If the organic acid concentration is less than 0.1 equivalent with respect to the total metal ion concentration, a sufficient effect cannot be obtained. If the organic acid concentration is more than 15.0 equivalent, an insoluble material is formed and the fluidity of the liquid is impaired. Therefore, the organic acid concentration was limited to 0.1 or more and 15.0 equivalents or less.
[0011]
The organic acid is preferably at least one selected from hydroxycarboxylic acids, carboxylic acids and amino acids. The hydroxycarboxylic acid is preferably at least one selected from lactic acid, hydroxybutyric acid, glycolic acid, mandelic acid, malic acid, tartaric acid, gluconic acid, citric acid, or soluble salts thereof. The carboxylic acid is preferably at least one selected from acetic acid, propionic acid, formic acid, oxalic acid, acrylic acid, malonic acid, ethylenediaminetetraacetic acid, or soluble salts thereof. The amino acid is preferably at least one selected from glycine, alanine, proline, valine, leucine, isoleucine, methionine, serine, cysteine, asparagine, glutamine, and tyrosine.
[0012]
Further, the present invention is the above electroplating method, characterized by containing 0.0001 mol / l or more and 5.0 mol / l or less ammonium ions and / or 0.0001 mol / l or more and 5.0 mol / l or less boric acid. This stabilizes the bath and makes it possible to form a film with a uniform thickness. If ammonium ion or boric acid is less than 0.0001 mol / l, plating spots are formed, and if it is more than 5.0 mol / l, an insoluble material is formed and the fluidity of the liquid is impaired. Therefore, ammonium ions and boric acid were limited to 0.0001 mol / l or more and 5.0 mol / l or less.
[0013]
Further, the present invention is the above electroplating method, wherein the plating bath contains bromine ions of 0.0001 mol / l or more and 5.0 mol / l or less, thereby suppressing generation of toxic chlorine gas. To do. If the bromine ion concentration is less than 0.0001 mol / l, no effect is seen, and if it exceeds 5.0 mol / l, a gas containing Br as a main component is generated, so the bromine ion concentration is 0.0001 mol / l or more and 5.0 mol / l. l Limited to below.
[0014]
Further, the present invention provides a plating bath having a sulfate ion of 0.0001 mol / l to 5.0 mol / l, a chloride ion of 0.0001 mol / l to 5.0 mol / l, a 0.0001 mol / l to 5.0 mol / l or less. Lithium ions, 0.0001 mol / l or more and 5.0 mol / l or less of sodium ions and / or 0.0001 mol / l or more and 5.0 mol / l or less of potassium ions In addition, the liquid voltage can be lowered and the covering power of plating can be improved, and a stable film composition can be obtained. If the above ion is less than 0.0001 mol / l, these effects are insufficient, and if it exceeds 5.0 mol / l, an insoluble material is formed, and the fluidity of the liquid is impaired. Therefore, these ion concentrations were limited to 0.0001 mol / l or more and 5.0 mol / l or less.
[0015]
【Example】
Example 1
A copper plate was degreased and washed as a base material. The plating solution is chromium chloride with a Cr ³⁺ concentration of 0.1 mol / l, ReO ₄ ⁻ of 0.01 mol / l, acetic acid: 1.5 mol / l, chloride other than ReO ₄ ⁻ and Cr ³⁺ ions, chloride A bath to which ammonium: 0.5 mol / l and potassium bromide: 0.5 mol / l was added was used. The pH was adjusted to 4 with sulfuric acid and sodium hydroxide, the liquid temperature was 35 ° C., and the electroplating was performed at a current density of 100 mA / cm ² .
[0016]
Example 2
ReO ₄ ^- except that the 0.1 mol / l concentration were electrolytic plating under the same conditions as in Example 1.
Comparative Example 1
ReO ₄ ^- except that the 0.0001 mol / l concentration were electrolytic plating under the same conditions as in Example 1.
Comparative Example 2
ReO ₄ ^- except that the 0.005 mol / l concentration were electrolytic plating under the same conditions as in Example 1.
[0017]
FIG. 1 shows the relationship between the plating film compositions of Examples and Comparative Examples and the molar concentration ratio of ReO ₄ ⁻ and Cr ³⁺ ions in the plating bath. From this, in the bath having a Cr ³⁺ concentration of 0.1 mol / l, when the ReO ₄ ⁻ of Comparative Example 1 is 0.0001 mol / l, the plating film composition is about 55 atomic% Re-45 atomic % Cr. When ReO ₄ ⁻ is 0.005 mol / l, it becomes about 92 atomic% Re-8 atomic % Cr. And, of the ReO ₄ Examples 1 and 2 ^- concentration of 0.01 mol / l or more (ReO ₄ ^- a concentration / Cr ³⁺ concentration 98 atomic% or more purity Re.
[0018]
【The invention's effect】
Since Re used for the corrosion-resistant film for high-temperature device members can be formed by aqueous solution electroplating, heat and corrosion resistance can be easily and inexpensively imparted to device members having complicated shapes.
[Brief description of the drawings]
FIG. 1 is a graph showing the relationship between plating film compositions of Examples and Comparative Examples, and ReO ₄ ⁻ concentration and ReO ₄ ⁻ / Cr ³⁺ concentration ratio in a plating bath.

Claims (2)

Containing perrhenate ions from 0.001 mol / l to 2.0 mol / l and Cr ³⁺ ions from 0.01 mol / l to 10.0 mol / l, and the perrhenate ions in the plating bath are Cr ³⁺ ions molar ratio is 0.1 or more, further 0.1 to 15.0 organic acid equivalent or less of a concentration relative to the total metal ion concentration, contained the following bromide 0.0001 mol / l or more 5.0 mol / l with respect to, pH is 0 5. Using a plating bath made of an aqueous solution having a liquid temperature of 10 to 80 ° C., it is characterized by forming a film with an atomic composition of Re of 98% or more and the remainder of Cr and inevitable impurities by electrolysis. Re film formation method by electrolytic plating. The electroplating according to claim 1, wherein the plating bath contains 0.0001 mol / l or more and 5.0 mol / l or less ammonium ions and / or 0.0001 mol / l or more and 5.0 mol / l or less boric acid. Re film formation method.

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