Coloring treatment method for copper alloy surface

Abstract

The invention discloses a coloring treatment method for a copper alloy surface, which belongs to the technical field of copper alloy products and comprises the following steps: S1, pretreatment: cleaning and activating the surface of a copper alloy matrix; s2, coloring liquid preparation, wherein soluble copper salt, a complexing agent, a pH buffering agent and a coloring accelerant are dissolved in deionized water, and the coloring liquid is formed; s3, coloring treatment is conducted, specifically, the copper alloy matrix treated in the step S1 is immersed in the coloring liquid; and S4, post-treatment is conducted, specifically, the colored copper alloy matrix is taken out, cleaned and dried, and a protective layer is optionally coated. According to the coloring treatment method for the surface of the copper alloy, coloring film layers with various colors including bronze color, chocolate color, blue color, purple color and brownish red color can be obtained on the surface of the copper alloy by controlling the coloring treatment time, and the requirements of the market for diversified appearances of copper alloy products are greatly met; and more design choices and creative space are provided for industries such as decoration and handicrafts.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of copper alloy products, in particular to a coloring treatment method for a copper alloy surface. BACKGROUND

[0002] In the wide application field of copper alloy products, such as the decoration, electronics, and handicraft industries, the requirements for the surface performance and appearance thereof are increasingly improved. The copper alloy itself has unique metallic luster and good physical and chemical properties, but the single metallic color is difficult to meet the diversified market demand. Therefore, coloring treatment is performed on the surface of the copper alloy to endow it with rich colors and unique appearance, which becomes an important research direction.

[0003] At present, the common coloring methods for the surface of the copper alloy mainly include chemical oxidation, electroplating, and physical vapor deposition. The chemical oxidation method is relatively simple to operate, but the types of coloring colors are limited, and the color stability is greatly affected by environmental factors, which is prone to problems such as fading and discoloration. The electroplating method can obtain various colors, but the process is complex, a large amount of chemicals and electricity are required, the cost is high, and the treatment of waste liquid generated in the electroplating process is difficult, which causes certain pressure on the environment. The physical vapor deposition method can prepare high-quality coloring film layers, but the equipment is expensive, the investment cost is high, and the operating environment is harsh, which is not suitable for large-scale industrial production.

[0004] In addition, the existing coloring treatment methods also have deficiencies in the bonding force between the coloring film layer and the copper alloy substrate, which easily leads to film layer peeling, affecting the service life and appearance quality of the product. Moreover, the components of some coloring liquids are complex, the preparation process is tedious, and it is difficult to accurately control the proportion of each component and the process parameters, thereby affecting the stability and consistency of the coloring effect.

[0005] Therefore, it is of important practical significance and broad market prospect to develop a coloring treatment method for the surface of a copper alloy, which is simple in process, low in cost, rich and stable in color, and has strong bonding force between the film layer and the substrate. SUMMARY

[0006] In view of the deficiencies of the prior art, the present application provides a coloring treatment method for the surface of a copper alloy, which has the advantages of rich and diverse colors, excellent film layer performance, low production cost, high production quality, and good environmental protection effect, and solves the problems raised in the background art.

[0007] To achieve the above-mentioned purposes, the present application provides the following technical solutions:

[0008] A coloring treatment method for the surface of a copper alloy, comprising the following steps:

[0009] S1, pretreatment: cleaning and activating the surface of a copper alloy substrate;

[0010] S2. Preparation of coloring solution: Dissolve soluble copper salt, complexing agent, pH buffer and coloring promoter in deionized water to form coloring solution;

[0011] The copper ion concentration in the coloring solution is 5-50 g / L, the pH value is maintained at 5.0-8.0, and the temperature is 20-80°C.

[0012] S3. Coloring treatment: Immerse the copper alloy substrate treated in S1 into the coloring liquid, or spray the surface of the substrate with the coloring liquid for a treatment time of 10 seconds to 30 minutes.

[0013] S4. Post-treatment: Remove the colored copper alloy substrate, clean and dry it, and optionally apply a protective layer.

[0014] Furthermore, the cleaning in S1 includes ultrasonic cleaning with an alkaline degreasing agent, and the activation in S1 includes immersion in a 5%-10% sulfuric acid or hydrochloric acid solution for 10-60 seconds.

[0015] Furthermore, the soluble copper salt in S2 is selected from at least one of copper sulfate, copper nitrate, and copper chloride.

[0016] Furthermore, the complexing agent in S2 is selected from at least one of citrate, tartrate, disodium EDTA, and triethanolamine; the molar ratio of the complexing agent to copper ions is (0.5:1) to (5:1).

[0017] Furthermore, the pH buffer in S2 is selected from at least one of the boric acid-borax buffer system and the phosphate buffer system.

[0018] Furthermore, the coloring promoter in S2 is at least one of a selenium compound, a tellurium compound, or a molybdate, and its concentration in the coloring solution is 0.01-5 g / L.

[0019] Furthermore, the selenium compound is sodium selenite or sodium selenate.

[0020] Furthermore, by controlling the coloring process time in S3, different colored film layers, including bronze, chocolate, blue, purple, and brownish-red, can be obtained on the copper alloy surface.

[0021] Furthermore, the protective layer in S4 is one of a transparent varnish, a wax layer, or an organosilicon film layer.

[0022] The present invention also provides a copper alloy article, comprising:

[0023] The thickness of the colored film layer is 0.1-5μm, the film layer has strong adhesion to the substrate, and the color is uniform and highly stable.

[0024] Compared with the prior art, the present invention provides a coloring treatment method for copper alloy surfaces, which has the following beneficial effects:

[0025] 1. This coloring treatment method for copper alloy surfaces, by controlling the coloring treatment time, can obtain a variety of different colored film layers on the copper alloy surface, including bronze, chocolate, blue, purple, and brownish-red, greatly satisfying the market demand for diverse appearances of copper alloy products. It provides more design options and creative space for industries such as decoration and handicrafts, achieving the advantage of rich and diverse colors. The coloring treatment method of this invention does not require the use of large amounts of heavy metal electroplating solution and consumes a lot of electricity, reducing energy consumption and environmental pollution. The components in the coloring solution are relatively environmentally friendly, and the waste liquid generated during the production process is easy to treat, meeting the requirements of current green manufacturing and sustainable development, and achieving the advantage of good environmental protection effect.

[0026] 2. The coloring treatment method for the surface of the copper alloy, the coloring film layer prepared by the method of the present invention has a thickness of 0.1-5μm, the film layer has strong bonding force with the substrate, which can effectively prevent the film layer from falling off and improve the service life of copper alloy products. At the same time, the coloring film layer has uniform color and high stability, and is not prone to fading or discoloration under different environmental conditions, ensuring the long-lasting beauty of the product appearance and achieving the advantages of excellent film layer performance.

[0027] 3. The coloring treatment method for the copper alloy surface is clear in its steps and easy to operate. It does not require complex equipment or harsh operating environment, and can effectively remove oil and oxides from the copper alloy substrate surface, thereby improving the surface activity. The coloring treatment can be carried out by immersion or spraying, and the treatment time is adjustable within a wide range. The post-treatment only requires cleaning, drying, and optionally applying a protective layer. The entire process is easy to realize for large-scale industrial production, reducing production costs and achieving the advantage of low production cost.

[0028] 4. The coloring treatment method for the copper alloy surface effectively controls the release rate of copper ions by clearly defining the components of the coloring solution, thereby affecting the process of the coloring reaction and the quality of the film formation. The addition of the coloring accelerator further accelerates the coloring reaction rate and improves the coloring efficiency. At the same time, the type and concentration of the coloring accelerator are also reasonably limited. By precisely controlling the type and proportion of each component of the coloring solution, the coloring effect is more stable and consistent, and a high-quality coloring film can be prepared. It not only has rich colors and excellent film performance, but also significantly improves the overall quality, achieving the advantage of high production quality. Attached Figure Description

[0029] Figure 1 This is a schematic flowchart of a coloring treatment method for copper alloy surfaces proposed in this invention. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Example 1 (Preparation of bronze-colored film):

[0032] Please see Figure 1 The coloring treatment method for a copper alloy surface in this embodiment includes the following steps:

[0033] S1. Pre-processing:

[0034] S1-1. Material Selection: Select an H62 brass plate (50mm×50mm×1mm) as the base material;

[0035] S1-2 Cleaning: Place it in an alkaline degreasing solution containing 50g / L sodium hydroxide and 30g / L sodium carbonate, and ultrasonically clean it at 60°C for 5 minutes to remove surface oil; then rinse thoroughly with deionized water.

[0036] S1-3 Activation: Immerse the cleaned brass plate in an 8% (v / v) dilute sulfuric acid solution for 30 seconds at room temperature to remove the surface oxide film and activate the surface; then rinse it again with deionized water and quickly proceed to the next step.

[0037] S2. Preparation of coloring solution:

[0038] Prepare 500 mL of the coloring solution in a glass beaker, with the following composition:

[0039] Soluble copper salt: Copper sulfate pentahydrate (CuSO4·5H2O), providing Cu 2+ Concentration 20 g / L;

[0040] Complexing agent: sodium citrate (Na3C3H3O7), with a molar ratio of 2:1 to copper ions;

[0041] pH buffer: Boric acid-borax buffer system, wherein the amount of borax (Na2B4O7·10H2O) added is 15g / L, which stabilizes the pH value of the solution at 6.5;

[0042] Coloring accelerator: Sodium selenite (Na2SeO3), added at a concentration of 0.5 g / L;

[0043] Make up to volume with deionized water, stir well, and keep the temperature of the coloring solution constant at 50°C using a water bath.

[0044] S3, Coloring Process:

[0045] The brass plate that has undergone S1 pretreatment is completely immersed in the coloring solution prepared in S2 for 4 minutes. During the process, the color of the brass surface can be observed to gradually change from bright yellow to light brown, and finally to a uniform bronze color.

[0046] S4. Post-processing:

[0047] S4-1, Chemical Removal: Remove the colored brass plate from the solution and immediately rinse it with plenty of deionized water to remove any residual chemical agents from the surface;

[0048] S4-2. Moisture removal: Dry the surface moisture with clean compressed air;

[0049] S4-3. Curing treatment: To enhance wear resistance and colorfastness, spray a layer of acrylic-based transparent varnish as a protective layer on its surface and cure it at 60°C for 30 minutes.

[0050] Example 2 (Preparation of the blue film):

[0051] This embodiment of a coloring treatment method for a copper alloy surface includes the following steps:

[0052] A1. Pre-processing:

[0053] A1-1. Material Selection: Select an H62 brass plate (50mm×50mm×1mm) as the base material;

[0054] A1-2 Cleaning: Place it in an alkaline degreasing solution containing 50g / L sodium hydroxide and 30g / L sodium carbonate, and ultrasonically clean it at 60°C for 5 minutes to remove surface oil; then rinse thoroughly with deionized water.

[0055] A1-3 Activation: Immerse the cleaned brass plate in an 8% (v / v) dilute sulfuric acid solution for 30 seconds at room temperature to remove the surface oxide film and activate the surface; then rinse it again with deionized water and quickly proceed to the next step.

[0056] A2. Preparation of coloring solution:

[0057] Prepare 500 mL of coloring solution with the following composition:

[0058] Soluble copper salt: Copper chloride (CuCl2·2H2O), providing Cu 2+ Concentration 10 g / L;

[0059] Complexing agent: potassium sodium tartrate (KNaC4H4O6), with a molar ratio of 3:1 to copper ions;

[0060] pH buffer: Disodium hydrogen phosphate-citric acid buffer system, which stabilizes the solution pH at 7.0;

[0061] Coloring accelerator: Ammonium molybdate ((NH4)2MoO4), added at a concentration of 2 g / L;

[0062] Make up to volume with deionized water, stir well, and keep the temperature of the coloring solution constant at 30°C.

[0063] A3. Coloring process:

[0064] The pretreated brass plate is immersed in the coloring solution for 90 seconds, and a bright and uniform blue film is quickly formed on the surface.

[0065] A4. Post-processing:

[0066] After cleaning and drying, without applying a protective layer, the performance test is carried out directly.

[0067] Example 3 (Preparation of brownish-red film):

[0068] This embodiment of a coloring treatment method for a copper alloy surface includes the following steps:

[0069] B1. Pre-processing:

[0070] B1-1. Material Selection: Select an H62 brass plate (50mm×50mm×1mm) as the base material;

[0071] B1-2 Cleaning: Place it in an alkaline degreasing solution containing 50g / L sodium hydroxide and 30g / L sodium carbonate, and ultrasonically clean it at 60°C for 5 minutes to remove surface oil; then rinse thoroughly with deionized water.

[0072] B1-3 Activation: Immerse the cleaned brass plate in an 8% (v / v) dilute sulfuric acid solution for 30 seconds at room temperature to remove the surface oxide film and activate the surface; then rinse it again with deionized water and quickly proceed to the next step.

[0073] B2. Preparation of coloring solution:

[0074] Prepare 500 mL of coloring solution with the following composition:

[0075] Soluble copper salt: Copper nitrate (Cu(NO3)2·3H2O), provides Cu 2+ Concentration 40 g / L;

[0076] Complexing agent: Disodium EDTA (C 10 H 14 The molar ratio of N2Na2O8 to copper ions is 1.5:1;

[0077] pH buffer: Boric acid-borax buffer system, maintaining pH value at 5.5;

[0078] Coloring accelerator: Sodium tellurate (Na2TeO4), added at a concentration of 0.1 g / L;

[0079] Make up the volume with deionized water, stir well, and keep the temperature of the coloring solution constant at 70°C.

[0080] B3. Coloring process:

[0081] The immersion treatment time is 15 minutes, and a dark brown-red film layer is formed on the surface.

[0082] B4. Post-processing:

[0083] After cleaning and drying, apply a layer of hot melt wax as a protective layer.

[0084] Comparative example:

[0085] The same H62 brass plate as in Example 1 was selected and subjected to the same pretreatment. It was immersed in a solution containing only 20 g / L copper sulfate (without complexing agent, buffer, or accelerator) and treated at 50°C for 4 minutes.

[0086] Results: A violent and uneven chemical displacement reaction occurred on the brass surface, forming a loose, powdery red copper film. This film was dull and uneven in color, easily rubbed off with a tissue, and had extremely poor adhesion.

[0087] Performance testing:

[0088] The colored samples obtained in Examples 1-3 were tested:

[0089] Appearance: The film has a uniform and continuous color with a rich gloss (the bronze color of Example 1 has a matte texture, and the blue color of Example 2 has a glossy texture).

[0090] Adhesion test: Using the cross-cut test (ASTM D3359), the film adhesion of all embodiments reached the highest level 5B (no peeling).

[0091] Corrosion resistance test: Neutral salt spray test (NSS test) is used.

[0092] The sample in Example 1 (protected by varnish) showed no obvious corrosion after 48 hours;

[0093] The surface color of the sample in Example 2 (without protection) began to darken after 6 hours, but there was no peeling or flaking.

[0094] The comparative sample showed severe corrosion and film peeling within 1 hour.

[0095] Film thickness measurement: The film thicknesses of Examples 1-3 were measured using an eddy current thickness gauge. The film thicknesses were approximately 1.2 μm, 0.5 μm, and 2.8 μm, respectively, all within the 0.1-5 μm range described in the claims.

[0096] in conclusion:

[0097] The above embodiments demonstrate that the copper alloy surface coloring treatment method provided by the present invention, through the reaction of a coloring liquid of specific components (including copper salt, complexing agent, buffer and accelerator) under controlled pH and temperature conditions, can form a colored conversion film with strong adhesion, uniform color and high stability on the copper alloy surface.

[0098] By flexibly adjusting the concentration of each component and the processing time, a variety of stable colors such as bronze, blue, and brownish-red can be obtained to meet the diverse needs of industrial production and artistic decoration.

[0099] The comparative examples demonstrate that the expected technical effect cannot be achieved without any of the key components of this invention.

[0100] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0101] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for coloring a copper alloy surface, characterized in that, Includes the following steps: S1. Pretreatment: Cleaning and activating the surface of the copper alloy substrate; S2. Preparation of coloring solution: Dissolve soluble copper salt, complexing agent, pH buffer and coloring promoter in deionized water to form coloring solution; The copper ion concentration in the coloring solution is 5-50 g / L, the pH value is maintained at 5.0-8.0, and the temperature is 20-80°C. S3. Coloring treatment: Immerse the copper alloy substrate treated in S1 into the coloring liquid, or spray the surface of the substrate with the coloring liquid for a treatment time of 10 seconds to 30 minutes. S4. Post-treatment: Remove the colored copper alloy substrate, clean and dry it, and optionally apply a protective layer.

2. The method for coloring a copper alloy surface according to claim 1, characterized in that: The cleaning in S1 includes ultrasonic cleaning with an alkaline degreasing agent, and the activation in S1 includes immersion in a 5%-10% sulfuric acid or hydrochloric acid solution for 10-60 seconds.

3. The coloring treatment method for a copper alloy surface according to claim 1, characterized in that: The soluble copper salt in S2 is selected from at least one of copper sulfate, copper nitrate, and copper chloride.

4. The coloring treatment method for a copper alloy surface according to claim 1, characterized in that: The complexing agent in S2 is selected from at least one of citrate, tartrate, disodium EDTA, and triethanolamine; the molar ratio of the complexing agent to copper ions is (0.5:1) to (5:1).

5. The coloring treatment method for a copper alloy surface according to claim 1, characterized in that: The pH buffer in S2 is selected from at least one of the boric acid-borax buffer system and phosphate buffer system.

6. The coloring treatment method for a copper alloy surface according to claim 1, characterized in that: The coloring promoter in S2 is at least one of a selenium compound, a tellurium compound, or a molybdate, and its concentration in the coloring solution is 0.01-5 g / L.

7. The coloring treatment method for a copper alloy surface according to claim 6, characterized in that: The selenium compound is sodium selenite or sodium selenate.

8. The coloring treatment method for a copper alloy surface according to claim 1, characterized in that: By controlling the coloring process time in S3, different colored film layers, including bronze, chocolate, blue, purple, and brownish-red, can be obtained on the copper alloy surface.

9. The coloring treatment method for a copper alloy surface according to claim 1, characterized in that: The protective layer in S4 is one of a transparent varnish, a wax layer, or an organosilicon film layer.

10. A color-treated copper alloy product, prepared by the color-treatment method for the copper alloy surface according to any one of claims 1-8, characterized in that, include: The thickness of the colored film layer is 0.1-5μm, the film layer has strong adhesion to the substrate, and the color is uniform and highly stable.

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