CN-122013190-A - Method for removing nickel plating layer on copper and copper alloy substrate

Abstract

The invention belongs to the technical field of metal surface treatment, and particularly relates to a method for removing a nickel plating layer on a copper and copper alloy substrate. In order to reduce the use of anti-staining salt and cyanide in the nickel stripping liquid, the main components of the nickel stripping liquid disclosed by the invention are a composite nickel stripping agent composed of ethylenediamine, ethylenediamine tetraacetic acid, ammonium persulfate and citric acid, a composite corrosion inhibitor composed of benzotriazole and sodium molybdate, the pH value of the nickel stripping liquid is 3-6, the nickel stripping temperature is 50-85 ℃, the nickel stripping speed is 1-2 mu m/h, and the surface of a copper alloy substrate is very bright and clean after a nickel layer is stripped, and the defects such as bloom and pitting are avoided.

Inventors

• Huan Yanchang
• YU SIYUAN
• WEI JIAO
• ZHAO YANG
• LIU TING
• LIU JIAOYANG
• ZHU YANAN
• LI WEI
• CHEN YUCONG
• SHI XIAOTONG

Assignees

• 沈阳瑞特热表动力科技有限公司

Dates

Publication Date

20260512

Application Date

20260204

Claims (7)

1. 1. A method for removing nickel coating on copper and copper alloy substrate is characterized by comprising the following steps of removing nickel coating on copper and copper alloy substrate by adopting nickel removing liquid, wherein the main components of the nickel removing liquid are ethylenediamine, ethylenediamine tetraacetic acid, a composite nickel stripping agent and a composite corrosion inhibitor, the composite nickel stripping agent is ammonium persulfate and citric acid, and the composite corrosion inhibitor is benzotriazole and sodium molybdate.
2. 2. The method for removing nickel plating on copper and copper alloy substrates according to claim 1, wherein the concentration of each component in the nickel removing liquid is 100ml/L-200ml/L of ethylenediamine, 10g/L-20g/L of ethylenediamine tetraacetic acid, 35g/L-115g/L of composite nickel stripping agent and 1.2g/L-6.5g/L of composite corrosion inhibitor.
3. 3. The method for removing nickel plating on a copper and copper alloy substrate according to claim 2, wherein the ammonium persulfate concentration in the composite nickel stripping agent is 20g/L-80g/L, and the citric acid concentration is 15g/L-35g/L.
4. 4. The method for removing nickel plating on a copper and copper alloy substrate according to claim 2, wherein the concentration of the benzotriazole in the composite corrosion inhibitor is 0.2g/L-1.5g/L, and the concentration of sodium molybdate is 1g/L-5g/L.
5. 5. The method for removing nickel plating from a copper and copper alloy substrate according to claim 1, wherein the pH of the nickel removing solution is 3-6.
6. 6. The method for removing nickel coating from copper and copper alloy substrate according to claim 5, wherein acetic acid is used to adjust the pH of the nickel removing solution.
7. 7. The method for removing nickel coating from copper and copper alloy substrate according to claim 1, wherein the nickel removal temperature is 50 ℃ to 85 ℃ and the nickel removal speed is 1 μm/min to 2 μm/min.

Description

Method for removing nickel plating layer on copper and copper alloy substrate Technical Field The invention belongs to the technical field of metal surface treatment, and particularly relates to a method for removing a nickel plating layer on a copper and copper alloy substrate. Background The nickel plating on the surface of the metal matrix has many advantages, and has the core characteristics that ① plating layers have excellent uniformity, no external electric field effect, deposition by virtue of chemical reduction reaction, the thickness of the plating layers is not influenced by the shape of parts, and uniform plating layers can be obtained for complex parts, deep cavity parts and blind hole parts. ② Hardness and wear resistance, the hardness in the plating state is about 400-500 HV, and the hardness after heat treatment can reach 500-900 HV. ③ The non-magnetic/low-magnetic high-phosphorus nickel coating (phosphorus content is more than 10%) is of an amorphous structure, is non-magnetic, and meets the non-magnetic requirement in the field of aerospace and electronics. ④ The plating solution has better environmental protection, does not contain cyanide, hexavalent chromium and other extremely toxic substances, accords with environmental protection standards such as RoHS and the like, can replace part of pollution plating process, and is widely applied to various fields. And when the nickel plating layer is not qualified, the nickel plating layer needs to be removed. At present, most of military enterprises in the aviation and aerospace fields also use cyanide-containing and salt-staining prevention chemical methods to remove unqualified nickel layers, and the method is mainly divided into copper alloy matrix nickel layer removal and steel matrix nickel layer removal, and the method of removing unqualified nickel layers by using extremely toxic substances such as cyanide-containing and salt-staining prevention is most commonly used, and the main formula of the nickel layer removal is shown in table 1. TABLE 1 Main solution formulation for removing Nickel layer In the process of stripping unqualified nickel layers of copper and copper alloy matrixes, the matrixes often have defects of bloom, pitting, rough surface and the like, and along with the increasing environmental protection requirements and the forbidden use of anti-dye salt and cyanide, the development of a nickel stripping method with small pollution and good environmental protection effect is urgently needed. Disclosure of Invention The invention provides a method for removing nickel coating on copper and copper alloy substrate, which comprises removing nickel coating on copper and copper alloy substrate by nickel removing liquid, wherein the nickel removing liquid comprises ethylenediamine, ethylenediamine tetraacetic acid, compound nickel stripping agent and compound corrosion inhibitor, the compound nickel stripping agent comprises ammonium persulfate and citric acid, and the compound corrosion inhibitor comprises benzotriazole and sodium molybdate; The nickel stripping solution comprises the following components of 100ml/L-200ml/L of ethylenediamine, 10g/L-20g/L of ethylenediamine tetraacetic acid, 35g/L-115g/L of composite nickel stripping agent and 1.2g/L-6.5g/L of composite corrosion inhibitor; further, in the composite nickel stripping agent, 20g/L to 80g/L of ammonium persulfate and 15g/L to 35g/L of citric acid are adopted; further, in the composite corrosion inhibitor, 0.2g/L to 1.5g/L of benzotriazol and 1g/L to 5g/L of sodium molybdate; The pH of the nickel removing liquid is 3-6, acetic acid can be used for fine adjustment of pH, the nickel removing temperature is 50-85 ℃, and the nickel removing speed is 1-2 μm/min The invention has the following beneficial effects: The invention does not contain extremely toxic substances such as anti-staining salt, chromic anhydride, cyanide and the like, and is an environment-friendly nickel removing method, wherein ammonium persulfate is a strong oxidant, the oxidation mechanism of the ammonium persulfate is closely related to the pH value of a solution, and the decomposition mechanism of the ammonium persulfate is mainly as follows when the pH value is less than 7: S 2O82-+H+→HSO4-+SO4-, the generated sulfuric acid free radical has extremely high oxidation-reduction potential (2.5V-3.1V), simple substance nickel in the chemical nickel layer can be oxidized into Ni 2+, the crystal structure of the nickel layer is damaged, the nickel layer is peeled off from the surface of a substrate, ethylenediamine can be used as a pH regulator, ethylenediamine tetraacetic acid can be used as a stabilizer, simultaneously, ethylenediamine and ethylenediamine tetraacetic acid can also be used as complexing agents, both have extremely strong complexing ability with nickel ions, and stable water-soluble complex is formed through coordination, ni 2+ is prevented from redeposition on the surface of a workpiece,