JP2015209579A - Colored member, method for manufacturing the same, liquid electrolyte, and concentration composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a colored member including a base material, a Cr based plating film on the base material and a chemical coating on the Cr based plating film, hardly dissolved even when immersed in hot water of about 60°C for 240 hours.SOLUTION: The colored member includes a chemical coating exhibiting an interference color and including Cr. The chemical coating has a region having a content of Cr gradually increased from a side far from a base material toward a side near to the base material, and the farthest region includes Cr and further includes one or more kinds of elements selected from P, Li, Ca, Mg, Mo, V, Nb, Ta, W, Zr, Fe, Ni, Co, Cu, Si, Ti, Zn, AL, Sn, Bi and lanthanoid. The method for manufacturing the colored member comprises PR-electrolyzing the member including the base material and the Cr based plating film as an object to be processed in a liquid electrolyte to form the chemical coating.

Description

  The present invention relates to a colored member, a method for producing the same, a liquid electrolyte, and a concentrated composition.

  In order to improve properties such as corrosion resistance of the Cr-based plating film provided on the substrate, chemical conversion treatment may be performed on the Cr-based plating film.

  For example, Patent Document 1 discloses an immersion treatment solution for rust prevention of a chromium plating film, which is made of an aqueous solution containing chromium phosphate.

JP 2010-209456 A

  In the above-mentioned Patent Document 1, in addition to the immersion treatment using the rust-proof immersion treatment liquid, as a pretreatment or a posttreatment of the immersion treatment, an electrolytic treatment is performed by using an article having a chromium plating film as a cathode. It is disclosed that the corrosion resistance of the plating film can be further improved.

  However, the present inventors have confirmed that a chemical conversion film formed by such cathodic electrolysis treatment may be dissolved when immersed in warm water of about 60 ° C. for a long time (for example, 240 hours). It was.

  In general, the appearance of the Cr-based plating film is silver, and it is considered unexpected that the treatment disclosed in Patent Document 1 causes an appearance change, particularly a color tone change by the treatment (Patent Document 1 paragraph). 0016). Therefore, in order for a member having a Cr-based plating film to have a controlled color appearance, spray coating is generally applied to the Cr-based plating surface. In addition, it was necessary to perform a spray coating process, and an increase in manufacturing cost was inevitable.

  The present invention is a colored member comprising a base material, a Cr-based plating film formed on the base material, and a chemical conversion film formed on the Cr-based plating film, and is immersed in warm water of about 60 ° C. for 240 hours Providing a colored member having a chemical conversion film that is difficult to dissolve even when applied, particularly a colored member having an interference color appearance, providing a method for producing such a colored member, and providing a liquid electrolyte used in such a production method It is an object of the present invention to provide a concentrated composition for producing such a liquid electrolyte.

  The present invention provided in order to provide the above-mentioned subject is as follows.

(1) A colored member comprising a base material, a Cr-based plating film formed on the base material, and a chemical conversion film having an interference color formed on the Cr-based plating film, A colored member containing Cr.

(2) The colored member according to (1), wherein the chemical conversion film includes a region in which a Cr content gradually increases from a side distal to the base material toward a side proximal to the base material. .

(3) The colored member according to (1) or (2), wherein a region farthest from the base material of the chemical film contains Cr.

(4) The chemical conversion film is made of P, Li, Ca, Mg, Mo, V, Nb, Ta, W, Zr, Fe, Ni, Co, Cu, Si, Ti, Zn, Al, Sn, Bi, and a lanthanoid. The colored member according to any one of (1) to (3), further containing one or more elements selected from the group consisting of:

(5) The method for producing a colored member according to any one of (1) to (4) above, wherein PR electrolysis is performed using a member including the base material and the Cr-based plating film as a processing target, A method for producing a colored member, comprising forming a chemical conversion film.

(6) The method for producing a colored member according to (5), wherein a PR ratio (+ :−) in the PR electrolysis is in a range of 1: 1 to 1: 9.

(7) In the PR electrolysis, the sum of the absolute value of the current density based on the maximum value of the positive peak current and the absolute value of the maximum value of the current density based on the negative peak current is 0.01 A / dm. ² or more 10A / dm ² or less, the production method of the colored member according to the above (5) or (6).

(8) A liquid electrolyte used in the method for producing a colored member described in any one of (5) to (7) above.

(9) From the group consisting of P, Cr, Li, Ca, Mg, Mo, V, Nb, Ta, W, Zr, Fe, Ni, Co, Cu, Si, Ti, Zn, Al, Sn and Bi and lanthanoids The liquid electrolyte according to (8) above, which contains an ionic substance containing one or more selected elements.

(10) The liquid electrolyte according to (9), wherein the content of the ionic substance is 0.01 mol / L or more and 5 mol / L or less in terms of the element.

(11) Any one of (8) to (10) above, which contains a carboxylic acid substance and a carboxylic acid substance composed of one or more substances selected from the group consisting of carboxylic acid and ions and salts of the carboxylic acid The liquid electrolyte as described.

(12) The liquid electrolyte according to (11), wherein the content of the carboxylic acid substance is 0.02 mol / L or more and 5 mol / L or less in terms of the carboxylic acid.

(13) The liquid electrolyte according to any one of (9) to (12), further including a substance having a reducing action.

(14) The liquid electrolyte according to (13), wherein the content of the substance having a reducing action is 0.0002 mol / L or more and 0.5 mol / L or less.

(15) A concentrated composition for producing the liquid electrolyte described in any of (8) to (14) above, comprising at least one component contained in the liquid electrolyte, The concentration in the liquid electrolyte is a concentration of 5 to 20 times the content of the liquid electrolyte.

  According to this invention, it is a coloring member provided with a base material, the Cr type plating film formed on the base material, and the chemical conversion film which exhibits the interference color formed on the Cr type plating film, About 60 degreeC A colored member provided with a chemical conversion film that is difficult to dissolve even if immersed in warm water for 240 hours is provided. Moreover, according to this invention, the concentrated composition for manufacturing the manufacturing method of the said colored member, the liquid electrolyte used for the said manufacturing method, and the said liquid electrolyte is also provided.

FIG. 1 is a graph showing the measurement results of the depth profile of the post-electrolysis member according to Example 1-5. FIG. 2 is a graph in which the display range of the vertical axis of the depth profile according to FIG. 1 is changed. FIG. 3 is a graph showing the measurement results of the depth profile of the post-electrolysis member according to Example 1-6.

  Hereinafter, embodiments of the present invention will be described.

1. Coloring member The coloring member which concerns on one Embodiment of this invention is equipped with the base material, the Cr type plating film formed on the base material, and the chemical conversion film which exhibits the interference color formed on the Cr type plating film.

(1) Substrate The type of the substrate is not limited as long as a Cr-based plating film can be formed on the surface. The base material may be comprised from the metal type material which has the electroconductive surface which can perform a Cr type plating film as it is. Alternatively, the base material may be one in which the surface of an insulating member made of plastic, ceramics, or the like is subjected to a process according to a known technique so that a Cr plating process can be performed. Examples of the metal-based material constituting the substrate include iron-based members, copper-based members, aluminum-based members, zinc-based members, magnesium-based members, and tin-based members. As an example of a base material obtained by performing an appropriate treatment on an insulating member, there is a so-called resin-plated member obtained by applying electrodeposition to the surface of a plastic material such as ABS resin and performing base electroplating.

  The shape of the substrate is not limited as long as a Cr-based plating film can be formed on the surface. It may have the shape of a so-called primary processed product such as a flat plate, a rod, a tube, or a block, or it may be the shape of a secondary processed product obtained by subjecting these primary processed products to further shape processing. Good. Specific examples of processing methods related to secondary processing include pressing, casting, molding, cutting, cutting, grinding, polishing, and the like. Specific examples of the secondary processed product include a screw, a nut, a hinge, a casing, a shaft, and a bent pipe.

  The surface on which the Cr-based plating film is formed on the substrate may be subjected to a treatment for facilitating the formation of the Cr-based plating film. Chromium plating is often processed with a thin film thickness of 1 micron or less as finish plating, and usually copper plating, nickel plating, or the like is applied as a base plating.

(2) Cr-based plating film In this specification, the Cr-based plating film means a generic term for a Cr plating film and a plating film containing Cr and other metals. The Cr-based plating film can be formed by electroplating that performs electrolysis using a base material as a cathode. The thickness of the Cr-based plating film is not limited. It is set appropriately according to the application. An example is about 0.1 to 1 μm.

(3) Chemical conversion film The colored member which concerns on one Embodiment of this invention is equipped with the chemical conversion film which exhibits the interference color formed on Cr type plating film. This chemical conversion film contains Cr. In one embodiment of the present invention, Cr contained in the chemical conversion film includes Cr derived from Cr contained in the Cr-based plating film. In one embodiment of the present invention, Cr contained in the chemical conversion film is composed of Cr derived from Cr contained in the Cr-based plating film.

  The chemical conversion film according to an embodiment of the present invention may have a concentration gradient structure in which the composition changes in the thickness direction. The details of the concentration gradient structure are not limited. As an example, a region in which the Cr content gradually increases from the side distal to the substrate toward the side proximal to the substrate, that is, from the surface side of the chemical conversion coating toward the substrate side. Prepare. By providing such a region, it becomes easy to achieve both excellent corrosion resistance due to containing Cr and reducing the amount of Cr eluted from the chemical conversion film.

  In the chemical conversion film according to an embodiment of the present invention, the region farthest from the substrate, that is, the outermost surface of the chemical conversion film may contain Cr. When the region farthest from the base material in the chemical conversion film contains Cr, it becomes easy to impart excellent corrosion resistance to the colored member.

  The chemical conversion film according to an embodiment of the present invention includes P, Li, Ca, Mg, Mo, V, Nb, Ta, W, Zr, Fe, Ni, Co, Cu, Si, Ti, Zn, Al, Sn, and One or more elements selected from the group consisting of Bi and lanthanoids may be further contained. These elements may contribute to improving various properties such as corrosion resistance and appearance of the chemical conversion film.

  The color exhibited by the chemical conversion film according to an embodiment of the present invention is not caused by the presence of a colored substance visually recognized in a specific color in the chemical conversion film, but the thickness, refractive index, etc. of the chemical conversion film. The interference color is caused by the fact that light of a specific color among the reflected light easily reaches the eyes of the observer. Therefore, the color tone exhibited by the chemical conversion film according to an embodiment of the present invention can be controlled by adjusting the conditions of chemical conversion treatment to vary the thickness of the chemical conversion film.

(4) Physical properties etc. Even if the coloring member which concerns on one Embodiment of this invention is a case where it is a case where it is immersed in 60 degreeC warm water for 240 hours, the chemical conversion film formed on Cr type | system | group plating film is hard to melt | dissolve. For example, when a chemical conversion film manufactured by the manufacturing method disclosed in Patent Document 1 is immersed in warm water at 60 ° C. for 240 hours, the chemical conversion film is easily dissolved, and the Cr-based plating film is exposed.

In the chemical conversion film of the colored member according to one embodiment of the present invention, the elution amount of the hexavalent chromium concentration tends to be 0.05 μg / cm ² or less as the concentration obtained by the analysis method based on EN15205. As described above, the chemical conversion film included in the colored member according to the embodiment of the present invention is difficult to dissolve even when immersed in warm water at 60 ° C. for 240 hours. It is difficult to elute as valent chromium.

2. Manufacturing Method of Colored Member (1) PR Electrolysis As long as the colored member according to one embodiment of the present invention has the above structural characteristics and physical properties, the manufacturing method is not limited. By manufacturing by the manufacturing method demonstrated below, the colored member which concerns on one Embodiment of this invention can be manufactured efficiently and stably.

  The manufacturing method of the colored member which concerns on one Embodiment of this invention is equipped with the process of performing PR electrolysis in a liquid electrolyte for the member provided with a base material and a Cr-type plating film, and forming a chemical conversion film.

  In this specification, PR (Periodic Reverse current) electrolysis means a method of performing electrolysis while performing polarity inversion. Since the polarity inversion is performed, the case where the PR electrolysis is performed is repeated between the case of anodic electrolysis and the case of cathodic electrolysis.

  The reason why the chemical conversion film according to one embodiment of the present invention is formed by performing PR electrolysis is not clear. The chemical conversion film according to an embodiment of the present invention may be formed as follows.

  That is, first, the object to be treated is subjected to anodic electrolysis, so that Cr located on the surface of the Cr plating film becomes an ionic substance and dissolves in the liquid electrolyte. If polarity reversal occurs before the ionic substance containing Cr dissolved from this Cr-based plating film diffuses into the liquid electrolyte, cathode electrolysis is performed on the object to be treated. The pH of the liquid electrolyte located in the vicinity increases. As a result, an ionic substance containing Cr contained in the liquid electrolyte located in the vicinity of the surface to be treated, or an ionic substance containing an element such as Mo optionally contained in the liquid electrolyte is a hydroxide. In addition, when the liquid electrolyte contains an ionic substance containing P, a layer for forming a part of the chemical conversion film or a part of the chemical conversion film is deposited on the surface to be treated as phosphorous oxide or the like. Is formed. Hereinafter, the layer containing the deposited substance is referred to as a deposited layer.

  When polarity reversal occurs again in this state, the deposited layer is considered to contain a hydroxide of Cr and the like. For this reason, it is considered that the electric field lines due to anodic electrolysis penetrate the deposition layer, and anodic electrolysis of the material constituting the Cr-based plating film located under the deposition layer proceeds. Since the ionic substance containing Cr and the like generated by this anodic electrolysis is blocked by the deposition layer and is difficult to diffuse into the liquid electrolyte, a large amount of the ionic substance exists between the deposition layer and the Cr-based plating film. It is thought that it becomes. Then, polarity reversal occurs again and cathode electrolysis is performed, so that the pH between the deposited layer and the Cr-based plating film rises, and ionic substances located in this part are hydroxides, phosphorus oxides, etc. Thus, it is considered that a new deposited layer is formed.

  It is considered that the deposited layer grows on the Cr-based plating film side by repeating the cycle consisting of the formation of the ionic substance containing the material constituting the Cr-based plating film by anodic electrolysis and the formation of the deposited layer by cathodic electrolysis. . In this case, the thicker the deposited layer when anodic electrolysis is performed, the more difficult the ionic substance containing the material constituting the Cr-based plated film diffuses into the liquid electrolyte. The closer to the surface, the higher the Cr content in the deposited layer.

  The PR ratio (+ :−) in PR electrolysis performed by the method for producing a colored member according to an embodiment of the present invention is not limited. In this specification, the PR ratio (+ :−) is the amount of current (current × time) from the power source during anodic electrolysis in PR electrolysis and from the power source during cathodic electrolysis. It means the ratio with the amount of current (current x time). The PR ratio (+ :−) in the method for producing a colored member according to an embodiment of the present invention is preferably in the range of 1: 1 to 1: 9, and the cathode electrolysis is superior to the anodic electrolysis. It is more preferably in the range of more than 1: 1 and 1: 9, particularly preferably in the range of 1: 2 to 1: 5. When cathodic electrolysis is excessively dominant, the film formation rate tends to be slow. When anodic electrolysis is excessively dominant, the amount of hexavalent chromium eluted from the chemical conversion film tends to increase.

  The applied current waveform in PR electrolysis performed by the method for manufacturing a colored member according to an embodiment of the present invention is not limited. What is necessary is just to set according to the characteristic of the chemical conversion film which should be formed. Specific examples of the current waveform include a rectangular wave, a sine wave, and a triangular wave.

Sum of absolute value of maximum value of positive side peak current and absolute value of maximum value of negative side peak current in PR electrolysis performed by manufacturing method of colored member according to one embodiment of the present invention (this specification) (Also referred to as “current amplitude” in the document) is not limited. What is necessary is just to set according to the characteristic of the chemical conversion film which should be formed. Current density amplitude defined in the same way as current amplitude (sum of absolute value of current density based on maximum value of positive peak current and absolute value of maximum value of current density based on negative peak current, unit : preferred examples of a / dm ^2), include 0.01 a / dm ² or more 10A / dm ² or less, more preferable examples include 0.1 a / dm ² or more 5A / dm ² or less.

  The electrolysis time in PR electrolysis performed by the manufacturing method of the coloring member which concerns on one Embodiment of this invention is not limited. What is necessary is just to set suitably with PR ratio (+ :-), the temperature of a liquid electrolyte, etc. so that a chemical conversion film may exhibit a predetermined color tone. In addition, as the electrolysis time is increased and the thickness of the chemical conversion film is increased, the color tone of the chemical conversion film usually changes to dark brown, purple, blue, and yellow. Therefore, whether or not the chemical conversion film has been formed can be determined by whether or not the surface to be processed has exhibited a brownish color tone.

(2) Liquid electrolyte The specific composition of the liquid electrolyte used when performing said PR electrolysis is not limited.

  Since it can be a component constituting a chemical conversion film formed during PR electrolysis, the liquid electrolyte is P, Cr, Li, Ca, Mg, Mo, V, Nb, Ta, W, Zr, Fe, Ni, Co. , Cu, Si, Ti, Zn, Al, Sn and Bi, and an ionic substance containing one or more elements selected from the group consisting of lanthanoids may be contained. Among these ionic substances, an ionic substance containing P is expected to be incorporated into the chemical conversion film as a phosphorus oxide. Mo, W, etc. may be present in the liquid electrolyte in the form of oxo acid. The content of the ionic substance in the liquid electrolyte is not limited. As an example, 0.01 mol / L or more and 10 mol / L or less are mentioned in element conversion. In the case of an ionic substance containing P, the content in the liquid electrolyte may be preferably 0.02 mol / L or more and 5 mol / L or less in terms of P, and may be 0.05 mol / L or more in terms of P. It may be more preferable that it is 3 mol / L or less.

  The liquid electrolyte may contain a carboxylic acid substance composed of one or two or more substances selected from the group consisting of carboxylic acid and ions and salts of the carboxylic acid.

  The carboxylic acid related to the carboxylic acid material is not limited. Examples of such carboxylic acids include monocarboxylic acids such as formic acid, acetic acid, propionic acid, pyruvic acid, benzoic acid, and acetylsalicylic acid; oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, Dicarboxylic acids such as sebacic acid, maleic acid, phthalic acid, terephthalic acid, gluconic acid; tricarboxylic acids such as tricarbaric acid; hydroxy such as glycolic acid, lactic acid, malic acid, tartaric acid, citric acid, ascorbic acid, salicylic acid, gallic acid Examples include carboxylic acids; and aminocarboxylic acids such as ethylenediaminetetraacetic acid (EDTA), nitriloacetic acid (NTA), glycine, alanine, and aminobenzoic acid (including anthranilic acid).

  The content of the carboxylic acid substance in the liquid electrolyte is not limited. The content of the carboxylic acid substance may be preferably 0.02 mol / L or more and 5 mol / L or less in terms of carboxylic acid, and is preferably 0.1 mol / L or more and 2 mol / L or less in terms of carboxylic acid. There is a case.

  The liquid electrolyte may contain a substance having a reducing action. Examples of such substances include organic substances such as L-ascorbic acid and inorganic substances such as sodium bisulfite.

  The content of the substance having the reducing action in the liquid electrolyte is not limited. The content of the substance having a reducing action may be preferably 0.0002 mol / L or more and 0.5 mol / L or less, and preferably 0.001 mol / L or more and 0.1 mol / L or less. There is a case.

  In addition to the above components, the liquid electrolyte may contain a solvent such as water, or an ionic substance derived from sodium sulfate, sodium chloride, or the like. The liquid electrolyte may contain a dispersoid.

  Since the pH of the liquid electrolyte rises during cathodic electrolysis and promotes the deposition of the gel substance, the pH of the liquid electrolyte is preferably 1 to 9, and more preferably 3 to 7.

  The method for producing the liquid electrolyte is not limited. The above components may be appropriately dissolved in a solvent such as water. In the case of containing a dispersoid, a substance that gives the dispersoid may be appropriately dispersed.

(3) Concentrated composition Said liquid electrolyte may be manufactured by the manufacturing method including the process of diluting the concentrated composition for manufacturing the said liquid composition. The concentrated composition in this case contains at least one component contained in the liquid electrolyte, and the content of the component in the liquid electrolyte is not less than 5 times and not more than 20 times the content of the liquid electrolyte. The concentration is preferable from the viewpoint of improving workability and reducing the footprint of raw materials. The concentrated composition is preferably such a composition that the liquid electrolyte can be obtained by diluting with a solvent from the viewpoint of improving workability.

  The embodiment described above is described for facilitating understanding of the present invention, and is not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

  Hereinafter, although the effect of the present invention is explained based on an example, the present invention is not limited to this.

Example 1
A liquid electrolyte containing the following components as shown in Table 1 and using the solvent as water was prepared.
Ingredient group A (electrolyte)
Phosphoric acid: 10 g / L to 20 g / L
Sodium sulfate: 20 g / L
Acetic acid: 20 g / L
Ingredient group B (metal salt)
Sodium molybdate: 5 g / L to 25 g / L
Sodium vanadate: 5 g / L to 20 g / L
Chromium phosphate: 5g / L
Ingredient group C (reducing agent)
Sodium bisulfite: 0.1 g / L to 1 g / L
L-ascorbic acid: 2 g / L

Electrodeposition is imparted to the surface of the test piece made of ABS resin, and subsequently, a member formed by applying copper and nickel plating as a base plating is used as a base material, and a Cr plating film is formed on this base material by about 0.5 μm. The electrolysis shown in Table 1 was performed on the following treatment target under the following conditions. Hereinafter, the member obtained by electrolysis is referred to as “post-electrolysis member”.
Bath temperature: Room temperature (23 ° C.) to 40 ° C.
Current density PR electrolysis: 0.05 A / dm ² or more and 0.5 A / dm ² or less Cathodic electrolysis: 0.05 A / dm ² or more and 0.5 A / dm ² or less PR ratio (+ :−): 1: 1 to 1: 4 (Cathode electrolysis is superior)
Processing time: 3-10 minutes

(Test Example 1) Confirmation of presence or absence of film formation Whether or not the post-electrolysis member has a chemical conversion film was evaluated by visual observation. As described above, the chemical film formed at the beginning (thin film thickness) has a dark brown interference color that exhibits an interference color, and the color tone then changes gradually to purple, blue, and yellow. When the appearance of an interference color appearance was observed, it was judged that a chemical conversion film was formed by electrolysis. The evaluation results are shown in Table 1. The meanings of the symbols in the figure are as follows.
A: It was recognized that a chemical conversion film was formed by electrolysis. B: It was not recognized that a chemical conversion film was formed by electrolysis.

(Test Example 2) Hot water immersion test The post-electrolysis member was immersed in warm water at 60 ° C for 240 hours. About the post-electrolysis member after immersion, whether or not the chemical conversion film was present on the post-electrolysis member was confirmed by visual observation similar to Test Example 1, and whether or not the chemical conversion film was dissolved by a warm water immersion test was evaluated. . The evaluation results are shown in Table 1. The meanings of the symbols in the figure are as follows.
A: It was not recognized that the chemical conversion film was dissolved by the hot water immersion test. B: It was recognized that the chemical conversion film was dissolved by the hot water immersion test.

(Test Example 3) Hexavalent chromium elution The electrolyzed member was subjected to an analysis method (diphenylcarbazide method) based on EN15205 to measure the elution amount of hexavalent chromium, and hexavalent chromium was eluted from the chemical conversion film. It was evaluated whether it was easy. The evaluation results are shown in Table 1. The meanings of the symbols in the table are as follows.
A: The hexavalent chromium concentration obtained by the above analysis method was 0.05 μg / cm ² or less. B: The hexavalent chromium concentration obtained by the above analysis method was more than 0.05 μg / cm ² .

(Depth profile measurement by XPS)
The surface of the post-electrolysis member obtained in Examples 1-5 and 1-6 was subjected to depth analysis using XPS. Measuring equipment, measuring conditions, etc. were as follows.
Measuring device: "JPS-9010 photoelectron spectrometer" manufactured by JEOL
Irradiation X-ray: MgKα ray Depth analysis: Ar sputter, SiO ₂ converted value Analytical elements: Cr, O, Mo and P
The results based on Example 1-5 are shown in FIGS. 1 and 2, and the results based on Example 1-6 are shown in FIG.

(Example 2)
A member in which a Cr plating film of about 0.5 μm is formed on a base material obtained by providing electrodeposition on an ABS resin and applying copper or nickel plating as a base plating (treated area: about 0.15 dm ² ) Was prepared for processing. Using this liquid electrolyte used in Example 1-5, PR electrolysis was performed on this treatment target under the following conditions.
Current waveform: A rectangular wave with a current amplitude of 0.3 A, bias adjustment was performed so that the positive peak current value was 0.15 A, and the negative peak current value was −0.15 A. Polarity inversion interval: Anode PR ratio (+ :−) set as shown in Table 2 with electrolysis time in the range of 1-9 seconds and cathode electrolysis time in the range of 1-9 seconds: By varying the polarity inversion interval, As shown in Table 2, the treatment time was set in the range of 9: 1 to 1: 9. The treatment time was 5 to 10 minutes until the blue interference color was visually observed until the chemical conversion film was formed. In the same manner as in Example 1, the warm water immersion test and the evaluation of hexavalent chromium elution were performed. The results are shown in Table 2.
In Examples 2-1 and 2-2, no color development was observed in the measurement by the diphenylcarbazide method. In Examples 2-3 and 2-4, although color development was observed in the measurement by the diphenylcarbazide method, the elution concentration of hexavalent chromium was 0.05 μg / cm ² or less. In Example 2-5, the elution concentration of hexavalent chromium was 0.1 μg / cm ² .

(Example 3)
A member in which a Cr plating film of about 0.5 μm is formed on a base material obtained by providing electrodeposition on an ABS resin and applying copper or nickel plating as a base plating (treated area: about 0.15 dm ² ) Was prepared for processing. Using this liquid electrolyte used in Example 1-5, PR electrolysis was performed on this treatment target under the following conditions.
Current waveform: Square wave with current amplitude of 0.3A Polarity reversal interval: 3 seconds (3 seconds for anodic electrolysis, 3 seconds for cathodic electrolysis)
PR ratio (+ :−): By varying the bias superimposed on the rectangular wave, the plus-side peak current value and minus-side peak current value are varied, and as shown in Table 2, 5: 1 to 1: Treatment time set to a range of 5: Performed until a blue interference color was visually recognized within a range of 5 to 10 minutes. In addition to confirming the time until a chemical conversion film was formed, the same as in Example 1 The hot water immersion test and hexavalent chromium elution were evaluated. The results are shown in Table 3.
In Examples 3-1 and 3-2, no color development was observed in the measurement by the diphenylcarbazide method. In Examples 3-3 and 3-4, although color development was observed in the measurement by the diphenylcarbazide method, the elution concentration of hexavalent chromium was 0.05 μg / cm ² or less. In Example 3-5, the elution concentration of hexavalent chromium was 0.2 μg / cm ² .

Claims (15)

A colored member comprising a base material, a Cr-based plating film formed on the base material, and a chemical conversion film exhibiting an interference color formed on the Cr-based plating film,
A colored member, wherein the chemical conversion film contains Cr.   2. The colored member according to claim 1, wherein the chemical conversion film includes a region in which a Cr content gradually increases from a side distal to the substrate toward a side proximal to the substrate.   The colored member according to claim 1 or 2, wherein a region distal to the base material of the chemical conversion film contains Cr.   The chemical conversion film is made of a group consisting of P, Li, Ca, Mg, Mo, V, Nb, Ta, W, Zr, Fe, Ni, Co, Cu, Si, Ti, Zn, Al, Sn, Bi, and a lanthanoid. The coloring member as described in any one of Claim 1 to 3 which further contains the 1 type (s) or 2 or more types of element chosen. A method for producing a colored member according to any one of claims 1 to 4,
A method for producing a colored member, comprising performing PR electrolysis in a liquid electrolyte on a member including the base material and the Cr-based plating film to form a chemical conversion film.   The method for producing a colored member according to claim 5, wherein a PR ratio (+ :−) in the PR electrolysis is in a range of 1: 1 to 1: 9. In the PR electrolysis, the sum of the absolute value of the current density based on the maximum value of the positive peak current and the absolute value of the maximum value of the current density based on the negative peak current is 0.01 A / dm ² or more and 10 A. The manufacturing method of the coloring member of Claim 5 or 6 which is / dm < ² > or less.   The liquid electrolyte used for the manufacturing method of the coloring member as described in any one of Claim 5 to 7.   1 selected from the group consisting of P, Cr, Li, Ca, Mg, Mo, V, Nb, Ta, W, Zr, Fe, Ni, Co, Cu, Si, Ti, Zn, Al, Sn and Bi, and a lanthanoid The liquid electrolyte according to claim 8, comprising an ionic substance containing a seed or two or more elements.   The liquid electrolyte according to claim 9, wherein the content of the ionic substance is 0.01 mol / L or more and 5 mol / L or less in terms of the element.   The liquid electrolyte according to any one of claims 8 to 10, comprising a carboxylic acid substance comprising a carboxylic acid and one or more substances selected from the group consisting of ions and salts of the carboxylic acid. .   The liquid electrolyte according to claim 11, wherein a content of the carboxylic acid substance is 0.02 mol / L or more and 5 mol / L or less in terms of the carboxylic acid.   The liquid electrolyte according to any one of claims 9 to 12, further comprising a substance having a reducing action.   The liquid electrolyte according to claim 13, wherein the content of the substance having a reducing action is 0.0002 mol / L or more and 0.5 mol / L or less.   A concentrated composition for producing a liquid electrolyte according to any one of claims 8 to 14, comprising at least one component contained in the liquid electrolyte, wherein the liquid electrolyte of the component The concentrated composition is characterized in that the content thereof is a concentration of 5 to 20 times the content of the liquid electrolyte.