Copper alloy passivation pretreatment pickling activator and preparation method thereof

Abstract

The invention discloses a copper alloy passivation pretreatment pickling activator. The copper alloy passivation pretreatment pickling activator comprises the following components in percentage by weight: 61.0%-63.8% of water, 10.0%-15.0% of citric acid, 10.0%-12% of sulfamic acid, 1.0%-2.0% of tween-20, 2.0%-3.0% of hydrogenated castor oil polyoxyethylene ether-20, 5.0% of glycerin, 0.2% of phenoxyethanol and 3.0%-6.0% of polyethylene glycol-600. The invention relates to mercaptan water system protection. In the formula, a nonionic surfactant with the hydrophilic-lipophilic balance value of 13 or above is selected, the acting force between hydroxyl oxygen or ether oxygen and copper atoms on the surface of the copper alloy is mainly hydrogen bonds, the hydrophilicity is higher than the lipophilicity, a layer of temporary anti-oxidation protective film can be formed on the copper alloy, the protective film can be replaced in a passivation solution, and the anti-oxidation effect is good. By the adoption of the passivation solution, the protective film on the surface can be removed through acid pickling to prepare for next passivation, and meanwhile a temporary protective film capable of being replaced by the passivation solution in the next step can be formed for copper.

Description

Technical Field

[0001] The present invention relates to the technical field of metal surface treatment, and particularly to a pickling activator for pre-treatment before passivation of copper alloy and a preparation method thereof. Background Art

[0002] Copper alloys are widely used in many fields, such as the electronics, electrical, hardware, and decoration industries. However, copper alloys are prone to oxidation corrosion in the natural environment, reducing their service life and appearance quality. To improve the corrosion resistance of copper alloys, passivation treatment is usually required. Passivation treatment can form a dense protective film on the surface of copper alloys, preventing oxygen, moisture, and other corrosive media from contacting the copper alloys, thereby effectively protecting the copper alloys.

[0003] In the process of copper alloy surface treatment, hexavalent chromium polishing is a commonly used method. Hexavalent chromium polishing can remove the oxide layer, stains, and other impurities on the surface of copper alloys, making the surface of copper alloys smoother and flatter, and improving their appearance quality. At the same time, hexavalent chromium polishing can also provide good surface conditions for subsequent passivation treatment, enhancing the adhesion and corrosion resistance of the passivation film.

[0004] Although hexavalent chromium polishing can improve the surface quality of copper alloys, there are still some active sites and impurities on the surface of the polished copper alloys, which will affect the quality and performance of the passivation film. Therefore, before passivation treatment, pre-treatment is required to remove the impurities and active sites on the surface of copper alloys, improving the quality and corrosion resistance of the passivation film. Pickling activator is a commonly used pre-treatment method before passivation.

[0005] The purpose of the pickling activator: First, it is to remove impurities. The pickling activator can chemically react with the oxide layer, stains, and other impurities on the surface of copper alloys, dissolving or converting them into substances that are easy to remove. Adjust the surface state. The pickling activator can adjust the microstructure and chemical composition of the surface of copper alloys, making it have a temporary protective effect. During passivation treatment, the exchange adsorption and film formation of active components can be completed as soon as possible, improving the quality and corrosion resistance of the passivation film.

[0006] The pickling activator for pre-treatment before passivation of copper alloy after hexavalent chromium polishing is mainly applied to fields with high requirements for the surface quality and corrosion resistance of copper alloys in industries such as electronics, electrical, hardware, and decoration. With the continuous development of these industries, the requirements for the quality and performance of copper alloy surface treatment are getting higher and higher. Therefore, the demand for efficient and environmentally friendly pickling activators is also increasing.

[0007] In summary, the pickling activator for copper alloy passivation pretreatment plays an important role in the surface treatment of copper alloy. It can remove impurities and active sites on the surface of copper alloy, improve the quality and corrosion resistance of the passivation film, and meet the requirements of different industries for the surface quality and performance of copper alloy.

[0008] However, after the copper alloy is polished with hexavalent chromium polishing liquid, a transparent trivalent chromium hydrogel protective film will be formed on the copper surface due to the strong oxidizing property of the hexavalent chromium polishing liquid. Since the active substances and additives contained in the hexavalent chromium polishing liquid will not dissolve the chromium film but will be preferentially adsorbed on the surface of the protective film, the hydrophobic protective film will be uneven in thickness, and problems such as color difference and spots will occur during the continued protection process. Therefore, copper or copper alloy (hereinafter referred to as copper alloy substitute) needs to be pickled before passivation, and the exposed bright copper alloy will be easily oxidized and discolored. How to pickle away the protective film on the surface to prepare for the next passivation step, while forming a temporary and replaceable protective film for copper is a problem to be solved. Summary of the invention

[0009] The purpose of the present invention is to provide a copper alloy passivation pre-treatment pickling activator and a preparation method thereof, so as to overcome the shortcomings of the prior art.

[0010] In order to achieve the above object, the present invention provides the following technical solutions: A copper alloy passivation pre-treatment pickling activator, comprising, by percentage: Water 61.0%~63.8% Citric acid 10.0%~15.0% Aminosulfonic acid 10.0%~12% Tween-20 1.0%~2.0% Hydrogenated castor oil polyoxyethylene ether-20 2.0%~3.0% Glycerin 5.0% Phenoxyethanol 0.2% Polyethylene glycol-600 3.0%~6.0% The preparation method of a copper alloy passivation pre-treatment pickling activator comprises: Step 1: Add citric acid and aminosulfonic acid to water in turn, stir thoroughly until completely dissolved, stir at room temperature for 30 minutes.

[0011] Step 2: Add Tween-20, hydrogenated castor oil polyoxyethylene ether-20, glycerin, polyethylene glycol 600, and fungicide phenoxyethanol to the above mixture in sequence, add the remaining water, and stir at room temperature for 30 minutes until a translucent stable state is reached.

[0012] Step 3: After passing the test, pack into barrels.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention relates to the protection of thiol water systems; a non-ionic surfactant with a hydrophilic-lipophilic balance value above 13 is selected in the formulation. The main force between the hydroxyl oxygen or ether oxygen and the copper atoms on the surface of the copper alloy is a hydrogen bond, and the hydrophilicity is stronger than the lipophilicity. A temporary anti-oxidation protective film can be formed on the copper alloy, and this protective film can be replaced in the passivation solution, and the final passivation film is used instead. Using the present invention can acid-wash the surface protective film to prepare for the next passivation, and at the same time can form a temporary protective film for copper that can be replaced by the next passivation solution. Detailed implementation modes

[0014] In order to make the above objects, features, and advantages of the present invention more obvious and understandable, many specific details are set forth in the following description for a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0015] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this invention belongs. The terms used in the specification of the present invention are only for the purpose of describing specific implementation modes and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0016] The present invention will be described in detail below in conjunction with each implementation mode: The formulation of Example 1 is as follows: Trade name Formulation amount (%) Water 63.8% Citric acid 15.0% Aminosulfonic acid 10.0% Tween-20 1.0% Hydrogenated castor oil polyoxyethylene ether-20 2.0% Glycerol 5.0% Phenoxyethanol 0.2% Polyethylene glycol 600 3.0% The preparation process of the above formulation is as follows: Step 1: Add citric acid and aminosulfonic acid to water in sequence, stir well until completely dissolved, and stir at room temperature for 30 min.

[0017] Step 2: Add Tween-20, hydrogenated castor oil polyoxyethylene ether-20, glycerol and polyethylene glycol-600, and fungicide phenoxyethanol to the above mixture in sequence, add the remaining water, and stir at room temperature for 30 minutes until a translucent stable state is reached.

[0018] Step 3: After passing the test, pack into barrels. Case formula 2 is as follows: Product Name Formula Amount (%) Water 61.0% Citric acid 10.0% Sulfamic acid 12.0% Glycerin 5.00% Hydrogenated Castor Oil Polyoxyethylene Ethyl Ether-20 3.0% Tween-20 2.0% Polyethylene glycol-600 6.0% Phenoxyethanol 0.2% The preparation process is as follows: Step 1: Add citric acid and aminosulfonic acid to water in turn, stir thoroughly until completely dissolved, stir at room temperature for 30 minutes.

[0019] Step 2: Add Tween-20, hydrogenated castor oil polyoxyethylene ether-20, glycerol and polyethylene glycol-600, and fungicide phenoxyethanol to the above mixture in sequence, add the remaining water, and stir at room temperature for 30 minutes until a translucent stable state is reached.

[0020] Step 3: After passing the test, pack into barrels. Among organic solid acids, aminosulfonic acid is a strong acid with high solubility. After dissolving, it is easily hydrolyzed into acidic ammonium sulfate, which can react with metal oxides, sulfates, phosphates, etc. to form iron, calcium, magnesium and other salts of aminosulfonic acid with high solubility, which can be rinsed with clean water. Citric acid is a polyhydroxy tricarboxylic acid with strong complexing ability. The two are used in combination to dissolve the chromium passivation after polishing of copper alloys, and the oxide layer on the surface can also be dissolved to form soluble salts. The formula uses a non-ionic surfactant with a hydrophilic-lipophilic balance value of more than 13. The interaction between hydroxyl oxygen or ether oxygen and the copper atoms on the surface of the copper alloy is mainly hydrogen bonding. The hydrophilicity is stronger than the lipophilicity. A temporary anti-oxidation protective film can be formed on the copper alloy to prevent oxidation and discoloration of the process parts, and ensure that the surface is clean and free of oxides for the next passivation, which affects the passivation effect.

[0021] The key technologies of this patent lie in the selection of organic acids for dissolving copper oxide and non-ionic surfactants. The selected organic acids are not easily adsorbed on the surface of copper alloys, which may affect the subsequent passivation process. For the subsequent copper protection, it is not a benzotriazole-based complex film-forming system, and an oxide needs to exist on the surface. This patent is aimed at a thiol protection system. Thiol directly reacts with copper atoms to form S-Cu bonds and hydrogen. Otherwise, a redox reaction occurs between copper ions and thiol, and the thiol becomes a sulfonic acid structure. The interaction force between the thiol and the surface copper changes from a covalent bond to an ionic bond, resulting in a significant reduction in the interaction force between the protection and the copper surface, and also a reduction in high-temperature resistance and hydrophobicity. Alkyl thiols are a class of water-insoluble organic compounds with good solubility in organic solvents such as alcohols and ethers. However, in large-scale industrial production, organic solvents are flammable and explosive. Therefore, this patent involves thiol aqueous protection.

[0022] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification. For those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of this invention patent shall be subject to the appended claims.

Claims

1. A copper alloy passivation pre-treatment pickling activator, characterized in that: Included in percentage: Water 61.0%~63.8% Citric acid 10.0%~15.0% Aminosulfonic acid 10.0%~12% Tween-20 1.0%~2.0% Hydrogenated castor oil polyoxyethylene ether-20 2.0%~3.0% Glycerin 5.0% Phenoxyethanol 0.2% Polyethylene glycol-600 3.0%~6.0%.

2. A method for preparing a copper alloy passivation pretreatment pickling activator according to claim 1, characterized in that: include: Step 1: Add citric acid and aminosulfonic acid to water in sequence, stir thoroughly until completely dissolved, stir at room temperature for 30 minutes; Step 2: Add Tween-20, hydrogenated castor oil polyoxyethylene ether-20, glycerin, polyethylene glycol 600, and fungicide phenoxyethanol to the above mixture in sequence, add the remaining water, and stir at room temperature for 30 minutes until it becomes a translucent stable state; Step 3: After passing the test, pack into barrels.