Copper alloy chemical polishing solution and preparation method thereof

Abstract

The invention discloses an environment-friendly copper alloy chemical polishing solution and a preparation method thereof. The environment-friendly copper alloy chemical polishing solution comprises the following components in parts by weight: 5-20% of an etching agent; 0.5-5% of a corrosion inhibitor; 0.5-5% of an oxidizing agent; 0.5-2% of a complexing agent; 0.02 to 0.5 percent of a sterilizing agent; and the balance of pure water. The preparation method comprises the following steps: adding pure water accounting for 50% of the total production amount into a preparation reaction kettle; adding an etching agent, and stirring to react for 1 hour; and sequentially adding the oxidizing agent and the corrosion inhibitor which are solvents of pure water, adding the complexing agent, stirring until the complexing agent is dissolved, adding the sterilizing agent, and finally adding the balance of pure water. The cleaning agent has the beneficial effects that potential safety hazards can be solved, organic strong acid is not used, and harm to human bodies is avoided; phosphorus and nitrogen heavy metals are not contained, and environment friendliness is achieved; the product is stable to use, automatic production can be achieved, the glossiness of the polished copper alloy can reach 60 degrees and is larger than 60 GU, and the size change of the polished workpiece is extremely small (smaller than 5 microns).

Description

Technical Field

[0001] The invention relates to the technical field of chemical polishing liquid, and in particular to a copper alloy chemical polishing liquid and a preparation method thereof. Background Art

[0002] Inorganic strong acids such as nitric acid, sulfuric acid, phosphoric acid, and hydrochloric acid are used in polishing liquids. A large amount of yellow smoke is produced during processing, which is extremely harmful to the human body. In addition, the use of nitric acid, sulfuric acid, and phosphoric acid not only puts a great pressure on environmental emissions, but also belongs to hazardous chemicals, which poses safety hazards when used. Environmentally friendly products on the market generally use strong oxidant hydrogen peroxide instead of nitric acid. Since hydrogen peroxide is unstable, it is easy to decompose during use, so there are disadvantages such as the polishing effect cannot be sustained, the temperature of the tank liquid increases during production, affecting the use effect, and adding hydrogen peroxide poses safety hazards.

[0003] It is difficult to realize automated production; due to the strong acid characteristics of the solution, the workpiece is exposed to the air for a long time (about 30 seconds) when it is taken out after polishing and enters the next process tank during automated production. It is not like manual transfer, which can quickly enter the next process tank (3-5 seconds). Therefore, the strong acid solution remaining on the surface of the workpiece in the air for a period of time will continue to react unevenly on the surface of the workpiece, causing the surface of the workpiece to be prone to flowery phenomenon, and the size of the workpiece is difficult to guarantee. The products on the market have strong copper etching ability, and often the size of the workpiece will be greatly changed during the polishing process, and the polishing process is difficult to control. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a phosphorus-free and nitrogen-free organic acid environmentally friendly copper alloy chemical polishing solution.

[0005] The technical scheme is as follows: A copper alloy chemical polishing solution, which includes the following components in parts by weight:

[0006] Etching agent: 5-20%;

[0007] Corrosion inhibitor: 0.5-5%;

[0008] Oxidant: 0.5-5%;

[0009] Complexing agent: 0.5-2%;

[0010] Fungicide: 0.05-0.5%;

[0011] Pure water balance.

[0012] Preferably, the etchant is one or more of tartaric acid, citric acid, lactic acid, acetic acid, malic acid, oxalic acid, formic acid, sulfinic acid, and aromatic acid.

[0013] Preferably, the corrosion inhibitor is one or more of boric acid, polycarboxylic acid, sulfonate and silicate.

[0014] Preferably, the oxidant is one or more of sodium molybdate, sodium metavanadate and sodium persulfate.

[0015] Preferably, the complexing agent is one or more of sodium gluconate and EDTA4Na.

[0016] Preferably, the bactericide is one or more of BK and MBM.

[0017] A method for preparing an environmentally friendly copper alloy chemical polishing solution comprises the following steps:

[0018] S1: Add 50% by weight of pure water into the preparation reactor;

[0019] S2: Add the etchant into the preparation reaction kettle in sequence, and stir the reaction for 1 hour;

[0020] S3: slowly adding the oxidant dissolved in pure water into the preparation reaction kettle in sequence;

[0021] S4: continue to slowly add the corrosion inhibitor dissolved in pure water into the preparation reaction kettle in sequence;

[0022] S5: adding the complexing agent to the preparation reaction kettle in sequence and stirring until completely dissolved;

[0023] S6: adding a bactericide to the preparation reactor;

[0024] S7: Continue to add the remaining amount of pure water into the preparation reaction kettle and stir for 1 hour to obtain the environmentally friendly copper alloy chemical polishing solution.

[0025] Preferably: in the step S2, one etchant is completely dissolved before adding the next etchant.

[0026] Preferably, the amount of pure water dissolved in steps S3 and S4 is 5% of the total production volume, and the temperature is greater than 70°C.

[0027] The copper alloy surface can continuously dissolve its surface bumps under the action of the etchant and the protection of the oxide, achieving a leveling effect on the surface bumps, and then the acid can smooth the incomplete crystallization of the microscopic surface under the action of the corrosion inhibitor, remove the tiny unevenness, and finally achieve a bright effect. Sodium gluconate is used to complex the dissolved metal impurity ions to prevent the impurity ions from depositing on the surface of the workpiece to cause pitting corrosion. The use of fungicides can maintain the stability of the product during storage and prevent the product from growing bacteria and corruption.

[0028] Compared with the prior art, the present invention has the following beneficial effects: it can solve potential safety hazards, does not use strong organic acids, and is harmless to the human body; it does not contain phosphorus and nitrogen heavy metals and is environmentally friendly; the product is stable in use and can be produced automatically; the glossiness of the polished copper alloy can reach 60°>60GU, and its surface has a strong ability to reflect light; the size of the workpiece after polishing changes very little (<5um), the polishing process does not change the dimensional accuracy and geometric shape accuracy of the workpiece, and the polishing process can be controlled. DETAILED DESCRIPTION

[0029] The present invention is further described below with reference to the embodiments.

[0030] Example 1

[0031] The components and proportions of a copper alloy chemical polishing solution are shown in Table 1 below:

[0032] Table 1 Components of Example 1

[0033]

[0034] A method for preparing a copper alloy chemical polishing solution comprises the following steps:

[0035] S1: Add 50% of the total production amount of pure water into the preparation reactor;

[0036] S2: Add tartaric acid, citric acid, oxalic acid and formic acid to the preparation reaction kettle in sequence, and stir to react for 1 hour. During the addition process, it is necessary to wait for one acid to be completely dissolved before adding the next acid;

[0037] S3: adding sodium persulfate and sodium molybdate dissolved in pure water with a temperature greater than 70°C, which accounts for 5% of the total production, into the preparation reaction kettle;

[0038] S4: adding boric acid polycarboxylic acid and sulfonate dissolved in pure water with a temperature greater than 70°C, which accounts for 5% of the total production, to the preparation reaction kettle;

[0039] S5: adding sodium gluconate to the preparation reaction kettle in sequence and stirring until completely dissolved;

[0040] S6: Adding fungicides BK and MBM to the preparation reactor;

[0041] Continue to add the remaining amount of pure water to the preparation reaction kettle and stir for 1 hour to obtain the environmentally friendly copper alloy chemical polishing solution.

[0042] Embodiment 2-6

[0043] Compared with Example 1, the components and proportions of Examples 2-6 are different, but the preparation methods are the same. The components and proportions of Examples 2-6 are shown in Table 2 below:

[0044] Table 2 Components of Examples 2-6

[0045]

[0046] Test example

[0047] Samples that have been subjected to the chemical polishing liquid produced by the present invention need to be evaluated, and the evaluation method includes appearance, glossiness and workpiece size.

[0048] 1. Appearance: Appearance is an important criterion for evaluating the quality of polishing. The appearance evaluation table is shown in Table 3 below:

[0049] Table 3 Appearance evaluation table

[0050] Effect Level Quality status Level 0 Very dull, the surface is worse than before polishing Level 1 Not shiny, no mirror effect, Level 2 The surface is slightly smoother and semi-brighter than before polishing, with a slight mirror effect. Level 3 The surface is smoother and brighter than before polishing, with a mirror effect Level 4 The surface is relatively flat, very bright, with a strong mirror effect, and the surface is particularly flat

[0051] 2. Glossiness

[0052] Glossiness is another important indicator for evaluating the quality of polishing, which depends on the reflectivity of the metal surface. When the product surface has high glossiness, it can create a delicate and high-quality effect visually, but if it is over-polished, the surface treatment will be too smooth, which is not in line with the actual use environment of the product. For some products, such as kitchen utensils, it is necessary to have a certain anti-slip function, so the precise control of glossiness is very important. Therefore, the 3nH YG268 three-angle high-precision gloss meter is used to measure the glossiness of the polished copper sheet, and the 60° measurement angle is used as a reference to determine its glossiness.

[0053] 3. Workpiece size

[0054] For the measurement of workpiece size, a micrometer is used to detect the size of the workpiece before and after processing, with an accuracy of 1um.

[0055] Test Example 1 Determination of Partial Base Liquid

[0056] The main etchants that can remove the oxide film of copper alloy are tartaric acid, citric acid, oxalic acid and formic acid. However, since the role of each base liquid component in the chemical polishing process is coordinated and restricted with each other, the reaction process of the mixed base liquid is relatively complicated. In order to determine the optimal concentration relationship between the reagents, this experiment uses orthogonal test to find the base liquid component with the best effect. When the number of experiments required by the factor design is too many, a part of the representative level combination is selected in principle for testing. The selected combinations have the characteristics of "uniform dispersion, neat and comparable". The results are shown in Table 4 below:

[0057] Table 4 Etching agent concentration ratio test table

[0058] serial number tartaric acid% Citric acid% oxalic acid% Formic acid% Appearance level Glossiness GU Sizeum 1 2.0 1.0 0.5 0.3 3 68 -3 2 2.0 3.0 1.0 0.6 2 58 -5 3 2.0 5.0 1.5 1.0 1 46 -8 4 4.0 1.0 1.0 1.0 3 62 -3 5 4.0 3.0 1.5 0.3 2 56 -5 6 4.0 5.0 0.5 0.6 2 55 -9 7 6.0 1.0 1.5 0.6 3 65 -4 8 6.0 3.0 0.5 1.0 2 53 -6 9 6.0 5.0 1.0 0.3 2 53 -9

[0059] The conclusion drawn through the poor test is: the higher the concentration of citric acid, the gloss and size are affected; the higher the concentration of tartaric acid, the less effect on the appearance gloss, the gloss is slightly reduced and the size is larger; the concentration of oxalic acid and formic acid has little effect on the gloss and size. The initial requirement for the base liquid is 2.0-6.0% tartaric acid, 0.5-1.0% citric acid, 0.5-1.5% oxalic acid, and 0.1-0.3% formic acid.

[0060] The optimal ratio range was confirmed by screening the oxidant complexing agent through single factor test:

[0061] Corrosion inhibitor: Boric acid polycarboxylic acid 0.5-1.5% Sulfonate 0.5-1.5%

[0062] Oxidant: Sodium molybdate 0.5-1.5% Sodium persulfate 0.5-1.5%

[0063] Complexing agent: sodium gluconate 0.5-1.0%

[0064] Passed the bacterial test and the original solution was stable after 6 months without the growth of bacteria and fungi.

[0065] Bactericide: BK 0.01-0.03% MBM 0.01-0.03%

[0066] Test Example 2

[0067] The copper alloy was polished using the obtained copper alloy chemical polishing solution. After the treatment, the glossiness of the copper alloy after polishing was measured using a 3nH YG268 three-angle high-precision gloss meter, and the glossiness was determined with a measurement angle of 60° as a reference.

[0068] Results: The glossiness of the copper alloy polished with the environmentally friendly copper alloy chemical polishing liquid reached 68GU, and its surface had a strong ability to reflect light.

[0069] Test Example 3 Workpiece Dimensions

[0070] The obtained environmentally friendly copper alloy chemical polishing liquid was used to polish the copper alloy. After the treatment, a micrometer was used to detect the size of the workpiece before and after the treatment, with an accuracy of 1um. The results are shown in Table 5 below.

[0071] Table 5 Workpiece size change after polishing

[0072] Serial number Initial size cm Size after processing cm Size change Eligibility 1 0.5825 0.5822 -3 qualified 2 0.5826 0.5824 -2 qualified 3 0.5825 0.5823 -2 qualified 4 0.5824 0.5821 -3 qualified 5 0.5826 0.5823 -3 qualified 6 0.5825 0.5823 -2 qualified

[0073] The glossiness of the copper alloy after polishing can reach 60°>60GU, and its surface has a strong ability to reflect light; the size of the workpiece after polishing changes very little (<5um), and the polishing process does not change the dimensional accuracy and geometric shape accuracy of the workpiece. The product is stable in use and can be produced automatically. The preparation industry does not contain phosphorus and nitrogen heavy metals, which is environmentally friendly and solves safety hazards. It does not use strong organic acids and is harmless to the human body.

[0074] Finally, it should be noted that the above description is only a preferred embodiment of the present invention. Under the guidance of the present invention, ordinary technicians in this field can make various similar expressions without violating the purpose and claims of the present invention, and such changes all fall within the scope of protection of the present invention.

Claims

1. A copper alloy chemical polishing solution, characterized in that: The composition comprises the following components in parts by weight: Etching agent: 5-20%; Corrosion inhibitor: 0.5-5%; Oxidant: 0.5-5%; Complexing agent: 0.5-2%; Fungicide: 0.02-0.5%; Pure water balance.

2. A copper alloy chemical polishing solution according to claim 1, characterized in that: The etchant is one or more of tartaric acid, citric acid, lactic acid, acetic acid, malic acid, oxalic acid, formic acid, sulfinic acid, and aromatic acid.

3. A copper alloy chemical polishing solution according to claim 1, characterized in that: The corrosion inhibitor is one or more of boric acid, polycarboxylic acid, sulfonate and silicate.

4. The copper alloy chemical polishing solution according to claim 1, characterized in that: The oxidant is one or more of sodium molybdate, sodium metavanadate and sodium persulfate.

5. The copper alloy chemical polishing solution according to claim 1, characterized in that: The complexing agent is one or more of sodium gluconate and EDTA4Na.

6. The copper alloy chemical polishing solution according to claim 1, characterized in that: The bactericide is one or more of BK and MBM.

7. A method for preparing a copper alloy chemical polishing solution as claimed in any one of claims 1 to 6, characterized in that: The following steps are involved: S1: Add 50% of the total production amount of pure water into the preparation reactor; S2: Add the etchant into the preparation reaction kettle in sequence, and stir the reaction for 1 hour; S3: slowly adding the oxidant dissolved in pure water into the preparation reaction kettle in sequence; S4: continue to slowly add the corrosion inhibitor dissolved in pure water into the preparation reaction kettle in sequence; S5: adding the complexing agent to the preparation reaction kettle in sequence and stirring until completely dissolved; S6: adding a bactericide to the preparation reactor; S7: Continue to add the remaining amount of pure water into the preparation reaction kettle and stir for 1 hour to obtain the environmentally friendly copper alloy chemical polishing solution.

8. The method for preparing a copper alloy chemical polishing solution according to claim 7, characterized in that: In the step S2, one etchant is completely dissolved before adding the next etchant.

9. The method for preparing a copper alloy chemical polishing solution according to claim 7, characterized in that: The amount of pure water dissolved in steps S3 and S4 is 5% of the total production volume, and the temperature of the pure water is greater than 70°C.

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