阅读说明：本技术 一种无氰无磷无氮一价铜镀铜溶液及其制备方法与应用 (Cyanide-free phosphorus-free nitrogen-free monovalent copper plating solution and preparation method and application thereof ) 是由 徐金来 胡耀红 赵国鹏 刘卫国 于 2021-07-26 设计创作，主要内容包括：本发明公开了一种无氰无磷无氮一价铜镀铜溶液及其制备方法与应用。该镀铜溶液以每升镀铜溶液计,由400～600ml开缸剂和400～600ml水组成；开缸剂包括以下组分：铜离子10～40g/L、碱金属氢氧化物30～80g/L、络合剂150～300g/L、导电盐20～50g/L、结晶细化剂0.07～2.00g/L。该镀铜溶液无氰、无磷、无氮的,无毒无害,废水处理简单,是国家大力和强制推广的清洁生产工艺；且较市场上二价镀铜液沉积速度快1倍,结晶细致光亮,与氰化镀铜沉积速度性能相当；使用时,能采用单一开缸和添加形式,操作简单,控制容易。(The invention discloses a cyanide-free phosphorus-free nitrogen-free monovalent copper plating solution and a preparation method and application thereof. The copper plating solution comprises 400-600 ml of a tank opening agent and 400-600 ml of water in terms of per liter of the copper plating solution; the jar opening agent comprises the following components: 10-40 g/L of copper ions, 30-80 g/L of alkali metal hydroxide, 150-300 g/L of complexing agent, 20-50 g/L of conductive salt and 0.07-2.00 g/L of crystallization refiner. The copper plating solution is cyanide-free, phosphorus-free and nitrogen-free, is nontoxic and harmless, has simple wastewater treatment, and is a clean production process which is vigorously and forcibly popularized by China; the deposition speed of the copper plating solution is 1 time faster than that of the divalent copper plating solution on the market, and the crystallization is fine and bright and is equivalent to the deposition speed of cyanide copper plating; when in use, the single cylinder opening and adding mode can be adopted, the operation is simple, and the control is easy.)

1. A cyanide-free phosphorus-free nitrogen-free monovalent copper plating solution is characterized in that: the copper plating solution is composed of 400-600 ml of a tank opening agent and 400-600 ml of water per liter;

the cylinder opening agent comprises the following components: 10-40 g/L of copper ions, 30-80 g/L of alkali metal hydroxide, 150-300 g/L of complexing agent, 20-50 g/L of conductive salt and 0.07-2.00 g/L of crystallization refiner.

2. The cyanide-free, phosphorus-free, nitrogen-free monovalent copper plating solution of claim 1, characterized in that:

the cylinder opening agent comprises the following components: 10-40 g/L of copper ions, 45-80 g/L of alkali metal hydroxide, 150-300 g/L of complexing agent, 20-50 g/L of conductive salt and 0.1-2.00 g/L of crystallization refiner.

3. The cyanide-free, phosphorus-free, nitrogen-free monovalent copper plating solution according to claim 1 or 2, characterized in that:

the copper ions are derived from at least one of cuprous chloride, cupric sulfate and cupric acetate;

the alkali metal hydroxide is one or two of sodium hydroxide and potassium hydroxide;

the complexing agent is a mixture of a reducing agent and a non-reducing agent;

the reducing agent is at least one of ascorbic acid, sodium ascorbate, potassium ascorbate, isoascorbic acid, sodium erythorbate and potassium erythorbate;

the non-reducing agent is one or at least two of malic acid, malonic acid, citric acid, tartaric acid, glucose, sodium gluconate, sodium malate, potassium malate, sodium malonate, sodium citrate, potassium tartrate and potassium sodium tartrate;

the conductive salt is one or at least two of sodium chloride, potassium chloride, sodium sulfate, potassium sulfate, sodium acetate and potassium acetate;

the crystallization refiner is one or at least two of selenium dioxide, sodium polydithio-dipropyl sulfonate, fatty alcohol-polyoxyethylene ether, sodium dodecyl sulfate and sodium hydroxyethyl sulfonate.

4. The cyanide-free, phosphorus-free, nitrogen-free monovalent copper plating solution according to claim 1 or 2, characterized in that:

the water is deionized water.

5. The method for preparing a cyanide-free, phosphorus-free and nitrogen-free monovalent copper plating solution according to any one of claims 1 to 4, characterized by comprising the steps of:

(1) dissolving a substance for providing copper ions, an alkali metal hydroxide, a complexing agent and a crystallization refiner by using water to obtain a jar opening agent; wherein the concentration of each component is 10-40 g/L of copper ions, 30-80 g/L of alkali metal hydroxide, 150-300 g/L of complexing agent, 20-50 g/L of conductive salt and 0.07-2.00 g/L of crystallization refiner;

(2) and (2) mixing the tank opening agent prepared in the step (1) with water, wherein the volume percentage of the tank opening agent is 40-60%, and the volume percentage of the water is 40-60%, so as to obtain the cyanide-free phosphorus-free nitrogen-free monovalent copper plating solution.

6. The use of the cyanide-free, phosphorus-free, nitrogen-free monovalent copper plating solution of any of claims 1-4 in the field of electroplating.

7. Use according to claim 6, characterized in that: the application is for copper plating of workpieces.

8. Use according to claim 7, characterized in that: the workpiece comprises an iron matrix, a zinc and zinc alloy matrix, an aluminum and aluminum alloy matrix and a copper and copper alloy matrix.

9. Use according to claim 7, characterized in that: the copper plating is carried out by using the cyanide-free, phosphorus-free and nitrogen-free monovalent copper plating solution as defined in any one of claims 1 to 4 in a rack plating mode and a barrel plating mode.

10. Use according to claim 9, characterized in that:

the conditions for hanging copper plating are as follows: electroplating by using the copper plating solution A, wherein the anode is electrolytic copper, the cathode is a part, the temperature is 40-60 ℃, the electroplating time is 1-5 min, and the cathode current density is 1.5-2A/dm²The current density of the anode is 0.5-1.5A/dm²(ii) a The composition of the copper plating solution A is as follows: 550-650mL/L, and the pH value is 9-11;

the condition of the copper barrel plating is as follows: electroplating by using the copper plating solution A, wherein the anode is electrolytic copper, the cathode is a part, the temperature is 40-60 ℃, the electroplating time is 30-120 min (determined according to the required thickness), and the cathode current density is 0.1-1A/dm²The current density of the anode is 1A/dm²(ii) a The composition of the copper plating solution A is as follows: 450-550 mL/L, pH 9-11.

Technical Field

The invention belongs to the field of electroplating, and particularly relates to a cyanide-free phosphorus-free nitrogen-free monovalent copper plating solution and a preparation method and application thereof.

Background

The conventional alkaline copper plating solution mainly comprises alkaline copper plating solutions containing cyanogen, and the above solution systems belong to non-environment-friendly processes, and the cyanogen-containing zinc leaching process is specifically listed as a removal process according to (fourteen) of removal categories in the "adjustment instruction for industrial structure" (2007), and alkaline copper plating solutions of copper pyrophosphate and alkaline copper plating solutions of HEDP organic polyphosphate both contain phosphorus, so that wastewater treatment has certain difficulty. Therefore, the research on the environment-friendly cyanide-free and phosphorus-free alkaline copper plating process is very necessary.

The cyanide-free system mainly comprises an alkaline copper pyrophosphate plating solution, an alkaline HEDP organic polyphosphate copper plating solution system, an ethylenediamine system and a biuret system. However, the above cyanide-free systems have the following disadvantages: the copper cyanide plating solution is in a divalent copper complexing form, the electroplating performance is far inferior to that of a cyanide copper plating system, the binding force is ensured by an electrified lower tank, the brightness is inferior to that of cyanide copper plating, the deposition speed is between one half and two thirds of that of cyanide copper plating, and the cyanide copper plating is obviously slower than that of cyanide copper plating; in addition, patent application also provides univalent cyanide-free copper plating, succinimide or dimethyl hydantoin is adopted as a complexing agent, but univalent copper in the system is easily oxidized into bivalent copper, the stability is poor, and the complexing agent contains nitrogen. The above system contains phosphorus or nitrogen, which brings a certain difficulty to the wastewater treatment.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a cyanide-free phosphorus-free nitrogen-free monovalent copper plating solution. The monovalent copper plating solution has the advantages that the bonding force, the crystallization fineness, the porosity performance and the deep plating capacity are basically consistent with those of cyanide copper plating, the deposition speed and the dispersion capacity are superior to those of cyanide copper plating, the monovalent copper plating solution can replace a virulent cyanide copper plating process, and the monovalent copper plating solution does not contain phosphorus or nitrogen, thereby realizing the purposes of environmental protection and clean production.

The invention also aims to provide a preparation method of the cyanide-free phosphorus-free nitrogen-free monovalent copper plating solution.

The invention also aims to provide application of the cyanide-free phosphorus-free nitrogen-free monovalent copper plating solution.

The purpose of the invention is realized by the following technical scheme: a cyanide-free phosphorus-free nitrogen-free monovalent copper plating solution comprises 400-600 ml of a cylinder opening agent and 400-600 ml of water per liter of the copper plating solution; preferably, the detergent consists of 450-600 ml of the cylinder opener and 400-550 ml of water.

The cylinder opening agent comprises the following components: 10-40 g/L of copper ions, 30-80 g/L of alkali metal hydroxide, 150-300 g/L of complexing agent, 20-50 g/L of conductive salt and 0.07-2.00 g/L of crystallization refiner; preferably comprising the following components: 10-40 g/L of copper ions, 45-80 g/L of alkali metal hydroxide, 150-300 g/L of complexing agent, 20-50 g/L of conductive salt and 0.1-2 g/L of crystallization refiner.

The water is preferably deionized water;

the copper ions are preferably derived from at least one of cuprous chloride, cupric sulfate and cupric acetate. In the case that the complexing agent is a reducing agent, such as ascorbic acid, sodium ascorbate, potassium ascorbate, isoascorbic acid, sodium erythorbate, and potassium erythorbate, the divalent copper ions are reduced to monovalent copper ions. Thus, in the case of using a divalent copper salt, the complexing agent needs to be a reducing agent or contain a reducing agent. When the copper ions are derived from at least one of copper chloride, copper sulfate and copper acetate, the complexing agent is at least one of ascorbic acid, sodium ascorbate, potassium ascorbate, isoascorbic acid, sodium erythorbate and potassium erythorbate; or at least one of ascorbic acid, sodium ascorbate, potassium ascorbate, isoascorbic acid, sodium erythorbate and potassium erythorbate.

The alkali metal hydroxide is preferably one or both of sodium hydroxide and potassium hydroxide.

The complexing agent is preferably a mixture of a reducing agent and a non-reducing agent;

the reducing agent is preferably at least one of ascorbic acid, sodium ascorbate, potassium ascorbate, isoascorbic acid, sodium erythorbate and potassium erythorbate;

the non-reducing agent is one or at least two of malic acid, malonic acid, citric acid, tartaric acid, glucose, sodium gluconate, sodium malate, potassium malate, sodium malonate, sodium citrate, potassium tartrate and potassium sodium tartrate.

The concentration of the reducing agent in the cylinder opening agent is preferably 10-60 g/L.

The concentration of the non-reducing agent in the cylinder opening agent is preferably 100-260 g/L.

The conductive salt is preferably one or at least two of sodium chloride, potassium chloride, sodium sulfate, potassium sulfate, sodium acetate and potassium acetate.

The crystallization refiner is preferably one or at least two of selenium dioxide, sodium polydithio-dipropyl Sulfonate (SP), fatty alcohol-polyoxyethylene ether (AEO-9), sodium dodecyl sulfate and sodium hydroxyethyl sulfonate (EHS).

The preparation method of the cyanide-free phosphorus-free nitrogen-free monovalent copper plating solution comprises the following steps:

(1) dissolving a substance for providing copper ions, an alkali metal hydroxide, a complexing agent and a crystallization refiner by using water to obtain a jar opening agent; wherein the concentration of each component is 10-40 g/L of copper ions, 30-80 g/L of alkali metal hydroxide, 150-300 g/L of complexing agent, 20-50 g/L of conductive salt and 0.07-2.00 g/L of crystallization refiner;

(2) and (2) mixing the tank opening agent prepared in the step (1) with water, wherein the volume percentage of the tank opening agent is 40-60%, and the volume percentage of the water is 40-60%, so as to obtain the cyanide-free phosphorus-free nitrogen-free monovalent copper plating solution.

The monovalent copper plating solution has the advantages of equivalent or even superior binding force, sedimentation velocity, crystallization fineness, deep plating capacity and porosity performance to cyanide copper plating.

The cyanide-free phosphorus-free nitrogen-free monovalent copper plating solution is applied to the electroplating field.

The above application is for copper plating of workpieces.

The workpiece comprises an iron matrix, a zinc and zinc alloy matrix, an aluminum and aluminum alloy matrix and a copper and copper alloy matrix.

The copper plating is carried out by using the monovalent copper plating solution and adopting a rack plating and barrel plating mode, wherein the specific operating conditions of the rack plating copper and the barrel plating copper and the subsequent process are as follows;

the conditions for hanging copper plating are as follows: electroplating by using the copper plating solution A, wherein the anode is electrolytic copper, the cathode is a part, the temperature is 40-60 ℃, the electroplating time is 1-5 min, and the cathode current density is 1.5-2A/dm²The current density of the anode is 0.5-1.5A/dm²(ii) a Copper platingThe composition of bath a was as follows: 550-650mL/L, and the pH value is 9-11; the following are preferred: electroplating by using the copper plating solution A, wherein the anode is electrolytic copper, the cathode is a part, the temperature is 40-60 ℃, the electroplating time is 3min, and the cathode current density is 2A/dm²The current density of the anode is 1A/dm²(ii) a The composition of the copper plating solution A is as follows: 550-650mL/L, pH 9-11.

The condition of the copper barrel plating is as follows: electroplating by using the copper plating solution A, wherein the anode is electrolytic copper, the cathode is a part, the temperature is 40-60 ℃, the electroplating time is 30-120 min (determined according to the required thickness), and the cathode current density is 0.1-1A/dm²The current density of the anode is 1A/dm²(ii) a The composition of the copper plating solution A is as follows: 450-550 mL/L, and the pH value is 9-11; the following are preferred: electroplating by using the copper plating solution A, wherein the anode is electrolytic copper, the cathode is a part, the temperature is 40-60 ℃, the electroplating time is 30-120 min (determined according to the required thickness), and the cathode current density is 0.1-1A/dm²The current density of the anode is 1A/dm²(ii) a The composition of the copper plating solution A is as follows: 500mL/L, pH 9-11.

The subsequent treatment process comprises the following steps: and then acid copper plating or nickel plating is carried out.

Compared with the prior art, the invention has the following advantages and effects:

(1) the invention adopts cyanide-free, phosphorus-free and nitrogen-free monovalent copper plating solution, is nontoxic and harmless, has simple wastewater treatment, and is a clean production process which is vigorously and forcibly popularized by China. Compared with the traditional cyanide-containing copper plating process, a 5000L copper plating bath can save 6000kg of sodium cyanide and reduce 1200m³The treatment of the cyanide-containing waste water and a large amount of cyanide-containing waste gas greatly reduces the pollution to the environment and improves the production efficiency.

(2) The invention adopts cyanide-free, phosphorus-free and nitrogen-free monovalent copper plating solution, has 1 time higher deposition speed than divalent copper plating solution on the market, and has fine and bright crystals with the deposition speed performance equivalent to cyanide copper plating.

(3) The process of the invention adopts a single cylinder opening and adding mode, and has simple operation and easy control.

Detailed Description

The present invention will be described in further detail with reference to examples, but the embodiments of the present invention are not limited thereto.

Example 1

(1) Preparing a cyanide-free phosphorus-free nitrogen-free copper plating solution:

dissolving cuprous chloride, sodium hydroxide, ascorbic acid, sodium potassium tartrate, potassium citrate, sodium chloride, fatty alcohol-polyoxyethylene ether (AEO-9) and SP (sodium polydithio-dipropyl sulfonate) by using deionized water to obtain a jar opener; wherein the concentration of each component is 30g/L of copper ions, 45g/L of sodium hydroxide, 10g/L of ascorbic acid, 100g/L of sodium potassium tartrate, 100g/L of potassium citrate and 20g/L, AEO-90.2 g/L, SP 0.07.07 g/L of sodium chloride; the pH value is 10;

② 450mL/L of cylinder opening agent, and the balance of deionized water to obtain cyanide-free, phosphorus-free and nitrogen-free copper plating solution.

(2) Electroplating an iron matrix in the cyanide-free copper plating solution, comprising the following steps:

pretreatment → water washing → activation → water washing → cyanide-free copper plating → subsequent process; the water washing step is washing by deionized water;

pretreatment: chemical degreasing (BH-13 (http:// www.honway.com.cn/product/showproduct. phpid ═ 40, process by instruction) produced by Guangzhou hong Bignong science and technology GmbH: → water washing → activation (10-30% hydrochloric acid solution, 3min) → water washing → copper plating → subsequent process.

The conditions for plating copper were as follows: electroplating by using the copper plating solution A, wherein the anode is electrolytic copper, the cathode is a part, the temperature is 40-60 ℃, the electroplating time is 3min, and the cathode current density is 2A/dm²The current density of the anode is 1A/dm²(ii) a The composition of the copper plating solution A is as follows: 500-600mL/L, pH 10;

③ the subsequent process: nickel plating (operating according to BH-986 bright nickel plating process, see http:// www.honway.com.cn/product/brown product. phpid ═ 25) → hot water washing → 100 ℃ oven drying.

Example 2

(1) Preparing a cyanide-free phosphorus-free nitrogen-free copper plating solution:

dissolving copper chloride, potassium hydroxide, isoascorbic acid, sodium gluconate, potassium chloride, sodium malonate and EHS (sodium hydroxyethyl sulfonate) by using deionized water to obtain a cylinder opener; wherein the concentration of each component is 10g/L of copper ions, 80g/L of potassium hydroxide, 15g/L of erythorbic acid, 100g/L of sodium gluconate, 50g/L of potassium chloride and 35g/L, EHS 2.0.0 g/L of sodium malonate; the pH is 11;

② 450mL/L of cylinder opening agent, and the balance of deionized water to obtain cyanide-free, phosphorus-free and nitrogen-free copper plating solution.

(2) Electroplating an iron matrix in the cyanide-free copper plating solution, comprising the following steps:

pretreatment → water washing → activation → water washing → cyanide-free copper plating → subsequent process; the water washing step is washing by deionized water;

pretreatment: chemical degreasing (BH-13 (http:// www.honway.com.cn/product/showproduct. phpid ═ 40, process by instruction) produced by Guangzhou hong Bignong science and technology GmbH:///www.honway.com.cn/product/showproduct. phpid ═ 40, water washing → activation (10-30% hydrochloric acid solution, 3min) → water washing → copper plating → subsequent processes.

③ the subsequent process: the same as in example 1.

Example 3

(1) Preparing a cyanide-free phosphorus-free nitrogen-free copper plating solution:

dissolving copper acetate, potassium hydroxide, sodium ascorbate, potassium citrate, potassium acetate, sodium dodecyl sulfate and sodium gluconate by using deionized water to obtain a jar opening agent; wherein the concentration of each component is 20g/L of copper ions, 80g/L of potassium hydroxide, 40g/L of sodium ascorbate, 110g/L of potassium citrate, 30g/L of potassium acetate, 0.1g/L of sodium dodecyl sulfate and 150g/L of sodium gluconate; the pH was 9.0;

② 450mL/L of cylinder opening agent, and the balance of deionized water to obtain cyanide-free, phosphorus-free and nitrogen-free copper plating solution.

(2) Electroplating the zinc alloy matrix in the cyanide-free copper plating solution, comprising the following steps of:

pretreatment → water washing → activation → water washing → cyanide-free copper plating → subsequent process; the water washing step is washing by deionized water;

pretreatment: chemical degreasing (BH-13 (http:// www.honway.com.cn/product/showproduct. phpid ═ 40, process as instruction) produced by Kyoto technologies GmbH, Guangzhou), process as instruction) → water washing → activation (0.01-0.02% sulfuric acid solution) → water washing → copper plating → subsequent process.

③ the subsequent process: the same as in example 1.

Example 4

(1) Preparing a cyanide-free phosphorus-free nitrogen-free copper plating solution:

dissolving copper sulfate, potassium erythorbate, potassium hydroxide, sodium gluconate, potassium citrate, potassium sulfate and AEO-9 by using deionized water to obtain a jar opener; wherein the concentration of each component is 40g/L of copper ions, 60g/L of sodium erythorbate, 60g/L of potassium hydroxide, 100g/L of sodium gluconate, 100g/L of potassium citrate and 30g/L, AEO-90.2 g/L of potassium sulfate; the pH was 9.5;

450ml/L of cylinder opening agent and the balance of deionized water to obtain the cyanide-free phosphorus-free nitrogen-free copper plating solution.

(2) After zinc is deposited on the aluminum alloy matrix, electroplating is carried out in the cyanide-free copper plating solution, and the steps are as follows:

pretreatment → water washing → activation → water washing → zinc deposition → water washing → cyanide-free copper plating → subsequent process; the water washing step is washing by deionized water;

pretreatment: chemical degreasing (BH-8 (http:// www.honway.com.cn/product/showproduct. phpid ═ 106, process by instruction) produced by Hongzhou Bignonian science and technology Co., Ltd.) → water washing → zinc deposition (http:// www.honway.com.cn/product/showproduct. phpid ═ 146) → water washing → copper plating → subsequent process.

③ the subsequent process: the same as in example 1.

Comparative example 1 divalent copper system

50g/L of copper sulfate, 200g/L of HEDP (hydroxyethylidene diphosphonic acid), 80g/L of potassium hydroxide, 30g/L of potassium carbonate, 0.05g/L of sodium selenite, 0.002g/L of 2-mercaptobenzimidazole, 55 ℃ of temperature and reaction time.

The copper electroplating step was the same as in example 1.

Comparative example 2 copper cyanide System

CuCN 40g/L、NaCN 50g/L、Na₂CO₃ 20g/L、KNaC₄H₄O₆30g/L, NaOH 10g/L, 0.0 g/L sodium selenite5g/L, 2g/L of antimony potassium tartrate, 0.1g/L of sodium polymethylene dinaphthalene sulfonate and 45 ℃ of temperature.

The copper electroplating step was the same as in example 1.

Comparative example 3N-containing cuprous copper System

25g/L of cuprous oxide, 1g/L of sodium hydroxide, 45g/L of acetylthiourea, 20g/L of potassium sodium tartrate and 3g/L of polyethyleneimine quaternary ammonium salt.

The copper electroplating step was the same as in example 1.

Comparative example 4

Compared with the example 2, the complexing agent does not contain a reducing agent system, and the details are as follows:

(1) preparing a cyanide-free phosphorus-free nitrogen-free copper plating solution:

dissolving copper chloride, potassium hydroxide, isoascorbic acid, sodium gluconate, potassium chloride, sodium malonate and EHS (sodium hydroxyethyl sulfonate) by using deionized water to obtain a cylinder opener; wherein the concentration of each component is 10g/L of copper ions, 80g/L of potassium hydroxide, 0g/L of erythorbic acid, 100g/L of sodium gluconate, 50g/L of potassium chloride and 35g/L, EHS 2.0.0 g/L of sodium malonate; the pH is 11;

② 450mL/L of cylinder opening agent, and the balance of deionized water to obtain cyanide-free, phosphorus-free and nitrogen-free copper plating solution.

(2) Electroplating an iron matrix in the cyanide-free copper plating solution, comprising the following steps:

pretreatment → water washing → activation → water washing → cyanide-free copper plating → subsequent process; the water washing step is washing by deionized water;

pretreatment: chemical degreasing (BH-13 (http:// www.honway.com.cn/product/showproduct. phpid ═ 40, process by instruction) produced by Guangzhou hong Bignong science and technology GmbH:///www.honway.com.cn/product/showproduct. phpid ═ 40, water washing → activation (10-30% hydrochloric acid solution, 3min) → water washing → copper plating → subsequent processes.

③ the subsequent process: the same as in example 1.

Comparative example 5

Compared with the embodiment 2, the content of the complexing agent reducing agent is less, and the specific content is as follows:

(1) preparing a cyanide-free phosphorus-free nitrogen-free copper plating solution:

dissolving copper chloride, potassium hydroxide, isoascorbic acid, sodium gluconate, potassium chloride, sodium malonate and EHS (sodium hydroxyethyl sulfonate) by using deionized water to obtain a cylinder opener; wherein the concentration of each component is 10g/L of copper ions, 80g/L of potassium hydroxide, 5g/L of erythorbic acid, 100g/L of sodium gluconate, 50g/L of potassium chloride and 35g/L, EHS 2.0.0 g/L of sodium malonate; the pH is 11;

② 450mL/L of cylinder opening agent, and the balance of deionized water to obtain cyanide-free, phosphorus-free and nitrogen-free copper plating solution.

(2) Electroplating an iron matrix in the cyanide-free copper plating solution, comprising the following steps:

pretreatment → water washing → activation → water washing → cyanide-free copper plating → subsequent process; the water washing step is washing by deionized water;

pretreatment: chemical degreasing (BH-13 (http:// www.honway.com.cn/product/showproduct. phpid ═ 40, process by instruction) produced by Guangzhou hong Bignong science and technology GmbH:///www.honway.com.cn/product/showproduct. phpid ═ 40, water washing → activation (10-30% hydrochloric acid solution, 3min) → water washing → copper plating → subsequent processes.

③ the subsequent process: the same as in example 1.

Comparative example 6

The difference from the example 1 is that the complexing agent does not contain sodium potassium tartrate, and the specific steps are as follows:

(1) preparing a cyanide-free phosphorus-free nitrogen-free copper plating solution:

dissolving cuprous chloride, sodium hydroxide, ascorbic acid, potassium citrate, sodium chloride, fatty alcohol-polyoxyethylene ether (AEO-9) and SP (sodium polydithio-dipropyl sulfonate) by using deionized water to obtain a cylinder opener; wherein the concentration of each component is 30g/L of copper ions, 45g/L of sodium hydroxide, 10g/L of ascorbic acid, 100g/L of potassium citrate and 20g/L, AEO-90.2 g/L, SP 0.07.07 g/L of sodium chloride; the pH value is 10;

② 450mL/L of cylinder opening agent, and the balance of deionized water to obtain cyanide-free, phosphorus-free and nitrogen-free copper plating solution.

(2) Electroplating an iron matrix in the cyanide-free copper plating solution, comprising the following steps:

pretreatment → water washing → activation → water washing → cyanide-free copper plating → subsequent process; the water washing step is washing by deionized water;

pretreatment: chemical degreasing (BH-13 (http:// www.honway.com.cn/product/showproduct. phpid ═ 40, process by instruction) produced by Guangzhou hong Bignong science and technology GmbH: → water washing → activation (10-30% hydrochloric acid solution, 3min) → water washing → copper plating → subsequent process.

The conditions for plating copper were as follows: electroplating by using the copper plating solution A, wherein the anode is electrolytic copper, the cathode is a part, the temperature is 40-60 ℃, the electroplating time is 3min, and the cathode current density is 2A/dm²The current density of the anode is 1A/dm²(ii) a The composition of the copper plating solution A is as follows: 600mL/L and pH value of 10;

③ the subsequent process: nickel plating (operating according to BH-986 bright nickel plating process, see http:// www.honway.com.cn/product/brown product. phpid ═ 25) → hot water washing → 100 ℃ oven drying.

Comparative example 7

The difference from the embodiment 3 is that the complexing agent does not contain sodium gluconate, and the content of the sodium ascorbate is increased, and the specific steps are as follows:

(1) preparing a cyanide-free phosphorus-free nitrogen-free copper plating solution:

dissolving copper acetate, potassium hydroxide, sodium ascorbate, potassium citrate, potassium acetate and sodium dodecyl sulfate by using deionized water to obtain a jar opening agent; wherein the concentration of each component is 20g/L of copper ions, 80g/L of potassium hydroxide, 190g/L of sodium ascorbate, 110g/L of potassium citrate, 30g/L of potassium acetate and 0.1g/L of sodium dodecyl sulfate; the pH was 9.0;

② 450mL/L of cylinder opening agent, and the balance of deionized water to obtain cyanide-free, phosphorus-free and nitrogen-free copper plating solution.

(2) Electroplating the zinc alloy matrix in the cyanide-free copper plating solution, comprising the following steps of:

pretreatment → water washing → activation → water washing → cyanide-free copper plating → subsequent process; the water washing step is washing by deionized water;

pretreatment: chemical degreasing (BH-13 (http:// www.honway.com.cn/product/showproduct. phpid ═ 40, process as instruction) produced by Kyoto technologies GmbH, Guangzhou), process as instruction) → water washing → activation (0.01-0.02% sulfuric acid solution) → water washing → copper plating → subsequent process.

③ the subsequent process: the same as in example 1.

Comparative example 8

The difference from the embodiment 3 is that the complexing agent does not contain sodium ascorbate, and the content of the sodium gluconate is increased, and the specific steps are as follows:

(1) preparing a cyanide-free phosphorus-free nitrogen-free copper plating solution:

dissolving copper acetate, potassium hydroxide, sodium ascorbate, potassium citrate, potassium acetate and sodium dodecyl sulfate by using deionized water to obtain a jar opening agent; wherein the concentration of each component is 20g/L of copper ions, 80g/L of potassium hydroxide, 0g/L of sodium ascorbate, 110g/L of potassium citrate, 30g/L of potassium acetate, 0.1g/L of sodium dodecyl sulfate and 190g/L of sodium gluconate; the pH was 9.0;

② 450mL/L of cylinder opening agent, and the balance of deionized water to obtain cyanide-free, phosphorus-free and nitrogen-free copper plating solution.

(2) Electroplating the zinc alloy matrix in the cyanide-free copper plating solution, comprising the following steps of:

pretreatment → water washing → activation → water washing → cyanide-free copper plating → subsequent process; the water washing step is washing by deionized water;

pretreatment: chemical degreasing (BH-13 (http:// www.honway.com.cn/product/showproduct. phpid ═ 40, process as instruction) produced by Kyoto technologies GmbH, Guangzhou), process as instruction) → water washing → activation (0.01-0.02% sulfuric acid solution) → water washing → copper plating → subsequent process.

③ the subsequent process: the same as in example 1.

And (3) performance testing:

(1) thermal shock test

The products electroplated in the examples 1-4 were subjected to a thermal shock test (iron base requirement 350 ℃, zinc alloy 150 ℃, and aluminum alloy 220 ℃), and the surface blister peeling was OK and the surface blister peeling was NG. The results are shown in Table 1.

TABLE 1 thermal shock test results

	350℃	150℃	220℃
				Example 1	OK
Example 2	OK
				Example 3		OK
Example 4			OK

The results in table 1 show that the invention can meet the thermal shock binding force test of steel, zinc alloy and aluminum alloy matrixes.

(2) Deposition rate, determined at different current intensities:

TABLE 2

	0.5A/dm2	1A/dm2	2A/dm2
				Example 1	0.20 micron/min	0.36 μm/min	0.72 micron/min
Example 2	0.18 μm/min	0.33 micron/min	0.68 μm/min
				Comparative example 1	0.10 micron/min	0.16 micron/min	0.32 μm/min
Comparative example 2	0.21 micron/min	0.34 micron/min	0.68 μm/min
				Comparative example 3	0.08 μm/min	0.16 micron/min	0.32 μm/min
Comparative example 4	0.08 μm/min	0.15 micron/min	0.32 μm/min
				Comparative example 5	0.12 micron/min	0.20 micron/min	0.40 micron/min

The results in Table 2 show that the copper plating solution provided by the invention has the deposition speed 1 time faster than that of the conventional divalent copper plating solution, and the crystallization is fine and bright and is equivalent to the deposition speed of cyanide copper plating.

(3) Deep plating ability

TABLE 3

The results in Table 3 show that the copper plating solution provided by the invention has stronger deep plating capability than the conventional divalent copper plating solution and cyanide copper plating solution.

(4) Copper anodic dissolution

TABLE 4

	Anodic dissolution
		Example 1	Normal dissolution of anode
Example 3	Normal dissolution of anode
		Comparative example 6	The anode is not normally dissolved and has powdery cuprous oxide on the surface
Comparative example 7	The anode is not normally dissolved and has powdery cuprous oxide on the surface
		Comparative example 8	The anode is not normally dissolved and has powdery cuprous oxide on the surface

Therefore, when the complexing agent is a reducing agent and a non-reducing agent, the anode can be effectively dissolved, and the copper plating effect is ensured.

After completion of the plating, the copper plating solutions of examples 1 to 4 were treated as follows: collecting waste water, carrying out copper precipitation on the waste water, and enabling the waste water reaching the standard to enter a comprehensive pool; the copper plating solution of comparative example 1 was treated as follows: collecting waste water, carrying out complex breaking and phosphorus precipitation on the waste water, then carrying out copper precipitation, and enabling the waste water reaching the standard to enter a comprehensive pool; the copper plating solution of comparative example 2 was treated as follows: collecting waste water, breaking cyanogen in the waste water, then carrying out copper precipitation, and enabling the waste water reaching the standard to enter a comprehensive pool

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.