CN112160002B

CN112160002B - Method for carrying out surface activation treatment on copper alloy surface

Info

Publication number: CN112160002B
Application number: CN202010970739.0A
Authority: CN
Inventors: 郑建国; 罗小平
Original assignee: Shenzhen Chonghui Surface Technology Development Co ltd
Current assignee: Chonghui semiconductor (Shenzhen) Co.,Ltd.
Priority date: 2020-09-15
Filing date: 2020-09-15
Publication date: 2021-05-28
Anticipated expiration: 2040-09-15
Also published as: CN112160002A

Abstract

The application discloses a method for carrying out surface activation treatment on a copper alloy surface. The method comprises the following steps: 1) carrying out electrolytic degreasing and water washing on a copper alloy part to be electroplated; 2) conveying the copper alloy to-be-electroplated part subjected to electrolytic degreasing and water washing into an activating solution and activating at room temperature; the activating solution is prepared from the following components: agent A, agent B and sulfuric acid; wherein the agent A is prepared from the following components: the agent A is prepared from the following components in percentage by volume: 70-90% of sodium persulfate, 0.5-5% of sodium chloride, 5-15% of citric acid and 4-10% of urea; the agent B is prepared from the following components: nonionic surfactant, ferric oxide and deionized water; 3) the method has the advantages that insufficient activation or excessive etching of the copper and copper alloy materials is improved, the production process is stable, and the method can adapt to the copper and copper alloy materials with different components.

Description

Method for carrying out surface activation treatment on copper alloy surface

Technical Field

The application relates to the technical field of activation in the LED electroplating industry, in particular to a method for carrying out surface activation treatment on a copper alloy surface.

Background

The electroplating is a processing process of taking a piece to be electroplated as a cathode in an electrolyte solution containing certain metal ions, and applying a certain waveform of low-voltage current to reduce the metal ions on the surface of the cathode into a metal simple substance by electrons and continuously depositing the metal simple substance as a metal coating. In the processes of processing, transporting, storing and the like, the surface of the part to be electroplated often has an oxide layer, microscopic salient points, rusty matters or other dirt, and the oxide layer, the microscopic salient points, the rusty matters or other dirt on the surface of the part to be electroplated made of copper alloy makes the surfaces of different copper or copper alloy materials rough and uneven, so that the surface roughness of the surfaces of different copper or copper alloy materials is different, and the surface roughness of different positions of the surface of the same copper or copper alloy material is also different. The surface roughness refers to the small pitch and the micro-valley unevenness of the surface of the copper or copper alloy material, and the distance between two peaks or two valleys (wave distance) is small (below 1 mm) and is difficult to distinguish by naked eyes, so that the surface roughness belongs to the micro-geometric shape error. The oxide layer, microscopic salient points, rusty matters or other matters on the surface of the copper alloy piece to be electroplated, which cause the roughness of the surface of the copper alloy piece to be electroplated, are collectively called as the oxide layer. If the plating layer is to be firmly attached to the surface of the copper or copper alloy material, the copper or copper alloy material needs to be subjected to a pretreatment for electroplating, which is generally carried out by degreasing → washing with water → etching/activation → washing with water.

At present, a great amount of sulfuric acid is generally adopted as an electrochemical etching or activating mode after an electroplated workpiece is degreased, the invention refers to the invention patent with the publication number of CN105568337A, the invention discloses a method for preprocessing in the electroplating process, a workpiece to be plated is subjected to degreasing and etching procedures, and bright etching solution adopted in the etching procedure comprises sulfuric acid with the mass fraction of 98%, concentrated nitric acid and hydrochloric acid with the mass fraction of 37%; the bright etching solution comprises the following components: 750g/L of sulfuric acid, 550g/L of concentrated nitric acid and 3-8g/L of hydrochloric acid.

With respect to the related art in the above, the inventors consider that there are the following drawbacks: with the development of the technology and the excavation of the cost, the components of the copper and copper alloy materials used as electroplating workpieces are changed continuously, the prior mode of using sulfuric acid as an electrochemical etching or activating mode can not meet the activating requirement of the existing materials, and the phenomenon of insufficient activation or excessive etching frequently occurs in the actual production process, namely, oxide layers, microscopic salient points, rusty substances or other dirt on the surfaces of the copper and copper alloy materials are not completely removed or the dirt is etched into the copper and copper alloy materials, so that the bonding force between the copper/copper alloy materials and a plating layer is difficult to ensure, the quality of products is seriously influenced, and the improvement of the production efficiency is restricted.

At present, some activated acids mainly comprising strong oxidizers are used in the market to solve the phenomenon of insufficient activation or excessive etching of copper and copper alloy materials, but the activated acids are very unstable in the production process, the activated acids need to be replaced when the actual production process is continuously carried out for 2 to 3 hours, the continuous production is very unfavorable, and the activated acids are not suitable for some copper materials and copper alloy materials and still have the phenomenon of insufficient activation or excessive etching.

Disclosure of Invention

The application provides a method for carrying out surface activation treatment on the surface of copper alloy, which has the advantages of improving insufficient activation or excessive etching of copper and copper alloy materials, stabilizing the production process and adapting to copper and copper alloy materials with different components.

In order to achieve the purpose, the application provides the following technical scheme:

a method for carrying out surface activation treatment on a copper alloy surface comprises the following steps: 1) carrying out electrolytic degreasing and water washing on a copper alloy part to be electroplated; 2) conveying the copper alloy to-be-electroplated part subjected to electrolytic degreasing and water washing into an activating solution and activating at room temperature; the activating solution is prepared from the following components: agent A, agent B and sulfuric acid; wherein the agent A is prepared from the following components: the agent A is prepared from the following components in percentage by volume: 70-90% of sodium persulfate, 0.5-5% of sodium chloride, 5-15% of citric acid and 4-10% of urea; the agent B is prepared from the following components: nonionic surfactant, ferric oxide and deionized water; 3) and (4) washing and drying the copper alloy to-be-electroplated part after activation to obtain an electroplated product.

Preferably, the agent B is prepared from the following components in percentage by volume: 2-6% of nonionic surfactant, 35-54% of ferric oxide and 40-60% of deionized water.

Preferably, the dosage of the agent A is 45-50g/L, B, the dosage is 0.2-0.8mL/L, and the dosage of the sulfuric acid is 2-8 mL/L.

Preferably, the pH of the activation solution is 1 to 4.

Preferably, the activation time is 3 to 45 s.

Preferably, the temperature required for activation is 25-50 ℃.

Preferably, the copper alloy part to be electroplated is subjected to electrolytic degreasing in degreasing liquid, the degreasing liquid comprises degreasing powder with the concentration of 60-90g/L, and the baume degree of the degreasing liquid is 4-12 DEG Be.

Preferably, the current required for electrolytic degreasing is 20-60A.

Preferably, the electrolytic degreasing time is 10-60 s.

Preferably, the electrolytic degreasing is performed at room temperature.

In summary, the present application includes at least one of the following beneficial technical effects:

1. the nonionic surfactant drives other components to permeate inwards together, so that the oxide layer is self-stripped, the removal of the oxide layer, microscopic salient points, rusty objects and the like on the surface of the copper alloy part to be electroplated is accelerated by the synergistic action of a small amount of chloride ions, sulfuric acid and sodium persulfate, the corrosion speed in a metal corrosion medium is reduced by urea, so that the copper material and the copper alloy material are not seriously corroded, the metal surface of the copper alloy part to be electroplated is in an activated state by the synergistic action of a small amount of citric acid and sulfuric acid, the bonding force between a plating layer and metal is ensured, the metal surface of the copper alloy part to be electroplated is smoother by the synergistic action of sodium persulfate, iron oxide and the nonionic surfactant, the brightening, grinding and leveling effects are achieved, the purpose of quickly removing the oxide layer is finally achieved, the plating layer bonding force of an electroplated product is improved, and the quality of the electroplated product is ensured, the method can adapt to copper or copper alloy materials with different components, improves the phenomenon of insufficient activation or excessive etching, is very stable in the production process, has the replacement period of the activation solution as long as 36 hours, and improves the production efficiency.

2. The non-ionic surfactant can reduce the volatilization of the activating solution, the concentration of sulfuric acid is slowly reduced by combining with sodium persulfate, the adopted non-ionic surfactant has good biodegradability and is environment-friendly, and through the synergistic effect with other various anions and cations in the activating solution, the consumption of the non-ionic surfactant is greatly reduced while an oxide layer and residual oil stains on the surface of a copper alloy workpiece to be electroplated are washed away, the accumulation and harm of harmful chemicals in the environment are reduced, and the non-ionic surfactant is energy-saving and environment-friendly.

3. The method increases the chemical polishing function of the copper material and the copper alloy material, achieves the polishing, grinding and activating functions of the copper material and the copper alloy material at the same time in the activation link, avoids the need of polishing, grinding and activating surface pretreatment step by step, and improves the production efficiency of a production line;

4. the method can remove the copper or copper alloy materials with different surface roughness, and has good activation effect even if the copper or copper alloy materials are seriously oxidized;

5. the method has a good activation effect for the material with serious skin explosion, and solves the problem that the copper or copper alloy material is difficult to produce due to serious skin explosion;

6. the method has the advantages of low production cost, contribution to popularization and application, and high economic benefit and industrial development value.

Drawings

FIG. 1 is an enlarged view of the copper alloy plated article of examples 1 to 10 and example 16 before activation.

FIG. 2 is a microscopic enlarged view of the plated products of examples 1 to 16 and comparative examples 7 to 8.

FIG. 3 is a microscopic enlarged view of the plated product of comparative examples 1 to 2.

FIG. 4 is a microscopic enlarged view of the plated products of comparative examples 3 to 6.

FIG. 5 is a microscopic enlarged view of the plated product of comparative example 9.

FIG. 6 is a microscopic magnification of the plated products of examples 1 to 16 after the adhesion test.

FIG. 7 is a microscopic enlarged view of the plated products of comparative examples 1 to 30 after adhesion test.

Description of reference numerals: 1. the surface is rough; 2. the surface is smooth; 3. marking lines of the marking test; 4. the plating layer does not fall off; 5. the plating layer comes off.

Detailed Description

The present application is described in further detail below with reference to figures 1-7.

Example 1

A method for carrying out surface activation treatment on a copper alloy surface comprises the following steps:

the first step is as follows: the method comprises the steps of conveying a copper alloy workpiece to be electroplated into degreasing solution, and carrying out electrolytic degreasing at room temperature, wherein the degreasing solution is strong in alkalinity, the current required by electrolytic degreasing is 45A, and the electrolytic degreasing time is 10s, so that the purpose of degreasing is achieved. And after the electrolytic degreasing step is finished, carrying out tertiary washing on the copper alloy part to be electroplated subjected to electrolytic degreasing at room temperature to clean the residual degreasing solution. The degreasing powder is purchased from Wenzhou Zhengbang chemical Co., Ltd, and is CF-W318, and the degreasing powder is obtained from a commercial channel and is not limited to the source of the degreasing powder.

The second step is that: and (3) conveying the copper alloy to-be-electroplated part subjected to electrolytic degreasing and water washing into an activating solution, and activating at room temperature, wherein the pH value of the activating solution is 3, the activating time is 15s, and the activating temperature is 45 ℃.

The activating solution is prepared from the following components: 0.2mL/L of the agent A (45 g/L, B agent) and 5mL/L of sulfuric acid. Wherein the agent A is prepared from the following components in percentage by volume: 78.5% of sodium persulfate, 2.5% of sodium chloride, 10% of citric acid and 9% of urea; the agent B is prepared from the following components in percentage by volume: 3% of nonionic surfactant, 37% of ferric oxide and 60% of deionized water.

The nonionic surfactant is purchased from BASF (China) GmbH, model AEO-9, and is available from commercial sources, and the source of the nonionic surfactant is not limited.

The third step: and after the activation step is finished, carrying out three-stage water washing on the copper alloy to-be-electroplated member after activation at room temperature to clean the residual activation solution. And then, drying the activated copper alloy part to be electroplated to dry the moisture on the surface of the copper alloy part to be electroplated at the drying temperature of 150 ℃, and finally obtaining an electroplated product.

The copper alloy to-be-electroplated part before electrolytic degreasing and activation is observed under a microscope under the condition of 20 times magnification, the related microscope magnified image is shown in figure 1, the dried copper alloy to-be-electroplated part is observed under the microscope under the condition of 20 times magnification, the related microscope magnified image is shown in figure 2, and the copper alloy to-be-electroplated part has a very good activation effect as can be seen from figure 2.

Examples 2 to 5

Examples 2-5 differ from example 1 in the parameters of each step. See table 1 for relevant detailed parameters. The effects of the copper alloy to-be-plated members used in examples 2 to 5 after activation are also shown in FIG. 2 (since the activation effects of the plated products obtained in examples 2 to 5 are slightly different from those of example 1, the plated products obtained in examples 2 to 5 are observed under a microscope of the same magnification to obtain images with high similarity, and FIG. 2 is used as an illustration of the activation effects for the sake of simplicity of reading).

1. TABLE 1 summary of parameters for each step of examples 1-5

Referring to table 1, as can be seen from fig. 1, the copper alloy to-be-electroplated member has a thick oxide layer on the surface thereof, the measured surface roughness Ra is 2.5-5 μm, the electroplated product shown in fig. 2 is obtained under the action of the activation solution, the measured surface roughness Ra is 0.08-0.16 μm, the rough and uneven surface of the different copper alloy to-be-electroplated members is greatly improved due to the oxide layer, micro-protruded points, rusts or other dirt on the surface of the copper alloy to-be-electroplated member, the micro-uneven surface of the copper alloy to-be-electroplated member is leveled, the copper alloy to-be-electroplated member without activation has dull luster, and is bright luster after activation, the effects of polishing, grinding and activating the copper alloy to-be-electroplated member are achieved simultaneously in the activation step, the product quality is greatly improved, and the production line efficiency is also greatly improved; and the activation temperature can also have good activation effect at room temperature, and the method is energy-saving and environment-friendly.

The oil removing step mainly removes oil stains and dirt on the surface of the copper alloy part to be electroplated, and the oil removing powder adopts an environment-friendly phosphorus-free formula, so that water eutrophication and ecological balance damage caused by phosphorus-containing wastewater generated by a commercially available phosphorus-containing formula are avoided, and meanwhile, the oil removing effect is good, and the oil removing efficiency is as high as 98.8%; the oil removing step is carried out at room temperature, so that the energy consumption defect that heating is needed to improve the oil removing effect and efficiency is avoided, and the oil removing method is energy-saving and environment-friendly.

The activation step mainly comprises the steps of corroding an oxide layer or impurities on the surface of the copper alloy part to be electroplated and activating the surface of the copper alloy part to be electroplated so as to enable the metal plating layer to have good bonding force. The surface tension of water can be obviously reduced by the nonionic surfactant at a very low concentration, the nonionic surfactant can quickly permeate between the metal surface and an oxide layer of a copper alloy part to be electroplated, other components are driven to permeate to the metal surface together, the oxide layer is self-stripped, the removal of the oxide layer, microscopic salient points, rusty substances and the like on the surface of the copper alloy part to be electroplated is accelerated by the synergistic action of a small amount of chloride ions, sulfuric acid and sodium persulfate, the corrosion speed in a metal corrosion medium is reduced by urea, so that the copper material and the copper alloy material are prevented from being seriously corroded, the metal surface of the copper alloy part to be electroplated is in an activated state by the synergistic action of a small amount of citric acid and sulfuric acid, the bonding force between a plating layer and metal is ensured, and the metal surface of the copper alloy part to be electroplated is smoother by the synergistic action of the sodium persulfate, the iron oxide and the nonionic surfactant, so that, Grinding and leveling to finally achieve the purpose of efficiently removing the oxide layer.

The nonionic surfactant can reduce the volatilization of the activating solution, and the concentration of the sulfuric acid is slowly reduced by combining with the sodium persulfate, so that the oxidation layer is ensured to quickly react with other components, the film formation is promoted, the loss of the activating solution is reduced, and the efficiency of removing the oil and the oxidation layer is improved. The adopted nonionic surfactant has good biodegradability and is environment-friendly, and through the synergistic effect with other anions and cations in the activation solution, the consumption of the nonionic surfactant is greatly reduced while oxide layers and residual oil stains on the surface of a copper alloy workpiece to be electroplated are washed away, the accumulation and harm of harmful chemicals in the environment are reduced, and the nonionic surfactant is energy-saving and environment-friendly.

Polar groups with opposite properties exist in the activating solution, for example, hydroxyl and carboxyl contained in citric acid are hydrophilic groups, amide groups of urea are hydrophilic groups, chloride ions are lipophilic groups and the like, the two polar groups with opposite properties in the activating solution can be adsorbed on the surface of a clean copper alloy workpiece to be electroplated to form a monomolecular film, and the two polar groups with opposite properties can form a film at an anode and a film at a cathode; the sodium persulfate prevents the diffusion of dissolved oxygen in water and water to the surface of the copper alloy part to be electroplated, so that a corrosion inhibition effect is achieved, the oxidation of the sodium persulfate enables the sodium persulfate to react with the metal of the copper alloy part to be electroplated without the help of the dissolved oxygen in water, a compact oxidation film is formed on the metal surface, and a small amount of nonionic surfactant can help the activating solution to form an oxidation film with a good effect on the metal surface. The formula is environment-friendly, the performance of the activating solution is stable, and the activating solution has higher economic benefit and industrial development value.

Examples 6 to 10

The difference between examples 6-10 and example 1 is that the parts to be electroplated of copper alloy come from different manufacturers, the components of the parts to be electroplated of copper alloy of different manufacturers and the mixture ratio of the components are different, and the parts to be electroplated of copper alloy related to examples 6-10 come from manufacturer a, manufacturer B, manufacturer C, manufacturer D and manufacturer E respectively and are only exemplary illustrations, and only for the purpose of explaining that the application can adapt to different copper materials and copper alloy materials. The copper alloy members to be plated used in examples 6 to 10 were activated. The effects of the copper alloys used in examples 6-10 after activation of the plated parts are also shown in FIG. 2. See table 2 for relevant detailed parameters.

TABLE 2 main components and proportions of copper alloy parts to be electroplated of examples 6-10 of different manufacturers

Referring to table 2, it can be seen from fig. 2 that the activation effect for different components and different proportions of the components is also very excellent for the copper alloy to-be-electroplated member, and the copper alloy can adapt to different copper materials and copper alloy materials.

Examples 11 to 15

Examples 11 to 15 differ from example 1 in the surface roughness of the copper alloy to be plated and the other steps, parameters and formulations are in agreement. The surface roughness of the copper alloy plating workpiece used in examples 11 to 15 is not limited to the surface roughness of the examples shown, and the surface roughness of the copper alloy plating workpiece according to the present invention is not limited to this surface roughness. The effects of the copper alloys used in examples 11-15 after activation of the plated parts are also shown in FIG. 2. See table 3 for relevant details.

TABLE 3 surface roughness of copper alloy to be plated for examples 11 to 16

Referring to table 3, after the copper and copper alloy materials are subjected to heat treatment, a very thick oxide layer is formed on the surface, and the maximum thickness can be as high as 10 μm or even more than 10 μm, and the existence of the surface state brings great difficulty to the surface treatment of the copper and copper alloy materials. The effects of the copper alloys used in examples 11-15 after activation of the plated parts are also shown in FIG. 2. As can be seen from Table 3 and FIG. 2, after the surface activation treatment is performed by the method of the present application, the activation effect is very excellent for different surface roughness of the surface of the copper alloy to-be-plated part, the removal effect for copper and copper alloy materials with thin oxide layers is even less than 0.1 μm, and the method can be adapted to the copper alloy to-be-plated parts with different surface roughness.

Comparative examples 1 to 10

Comparative examples 1 to 10 are different from example 1 in the parameters of the activation step and the composition of the activation solution, and the state of the copper alloy member to be plated used in comparative examples 1 to 2 after the surface activation treatment is shown in FIG. 3, the state of the copper alloy member to be plated used in comparative examples 3 to 6 after the surface activation treatment is shown in FIG. 4, the state of the copper alloy member to be plated used in comparative examples 7 to 8 after the surface activation treatment is shown in FIG. 2, and the state of the copper alloy member to be plated used in comparative example 9 after the surface activation treatment is shown in FIG. 5. See table 4 for relevant detailed parameters and results.

TABLE 4 comparison of results for comparative examples 1-10 and example 1

Referring to table 4, the electroplating industry of comparative examples 1-9 using strong acid based activation solutions typically also requires electrical energization to perform the activation step. Under the conditions of the same current and the same activation time adopted in the comparative examples 1 and 2, although the removal of the oxide layer can be accelerated by increasing the sulfuric acid concentration, as can be seen from fig. 3, the change of the sulfuric acid concentration has a small influence on the activation effect, which may be the adverse effect that the increase of the sulfuric acid concentration corrodes the metal surface of the copper alloy plated part to increase the surface roughness of the copper alloy plated part.

Compared with the comparative example 2, the comparative example 3 and the comparative example 4 respectively increase the current and prolong the activation time, and as can be seen from fig. 4, the change of the current has certain influence on the activation effect, the current intensity is increased, the activation speed of the copper alloy part to be electroplated is higher, but the plating layer in the high-current region is thick, rough and easy to scorch, so that the material with large surface roughness can not be normally produced; the activation time is prolonged, the current intensity is not changed, the copper alloy part to be electroplated is easy to plate uniformly, the copper alloy part to be electroplated with large surface roughness can be better, but the work efficiency is influenced by the extension of the activation time of the copper alloy part to be electroplated, and the production line is difficult to apply.

The hydrochloric acid has excellent activation effect on the copper alloy to-be-electroplated part, so the hydrochloric acid is added in small amount in comparative examples 5-7 to improve the activation effect, referring to fig. 4 and 5, after the hydrochloric acid is added in small amount, the activation effect is enhanced, but the addition amount is only within 2ml/l, the production line operation is difficult to control, the corrosion degree is increased along with the increase of the hydrochloric acid dosage, the smoothness of the electroplated product is reduced, the surface roughness of the electroplated product is increased, probably because the hydrochloric acid is easy to form dezincification over corrosion on the copper alloy to-be-electroplated part, and the metal surface of the copper alloy to-be-electroplated part is easy to excessively corrode, so that the surface roughness of.

Comparative example 8 adopts the mixed acid mode to carry out the activation step to copper alloy waiting to electroplate piece, refer to fig. 5, the mixed acid activation mode has better activation effect, but nitric acid can produce nitrogen oxide yellow smoke, seriously pollutes the air, and production line verification is unstable simultaneously, and the product interval nature appears the phenomenon of activation inadequately or etching is excessive.

Comparative example 9, in which sodium bisulfate is used as a main component for activation and sodium bisulfate is a strong electrolyte, can make the metal surface of a copper alloy member to be plated exhibit a stable activated state, see fig. 5, and the removal effect of an oxide layer is not ideal due to insufficient acidity of sodium bisulfate.

Comparative examples 10 to 28

Comparative examples 10 to 22 differ from examples 1 to 5 in that: comparative examples 10 and 11 used less or more sodium persulfate in the agent a than in the agents a used in examples 1-5, respectively; the agents A used in comparative examples 12 and 13 have the amount of sodium chloride less than or more than the amount of sodium chloride in the agents A used in examples 1 to 5, respectively; the agents A used in comparative examples 14 and 15 have the citric acid amount less than or more than the citric acid amount used in the agents A used in examples 1 to 5, respectively; see table 5 for relevant detailed parameters for comparative examples 10-15;

comparative examples 16 and 17 used agents A in which the amount of urea was less or more than that of the agents A used in examples 1 to 5, respectively; the amount of the nonionic surfactant in the agent B used in comparative examples 18 and 19 was less than or more than that in the agent B used in examples 1 to 5, respectively; comparative examples 20 and 21 used agents B in which the amount of iron oxide was less or more than that of the agents B used in examples 1 to 5, respectively; see table 6 for relevant detailed parameters for comparative examples 16-21;

the agents A used in comparative examples 22 and 23 are used in amounts less than or more than the agents A used in examples 1 to 5, respectively; comparative examples 24 and 25 used less or more of the agent B than those used in examples 1 to 5, respectively; comparative examples 26 and 27 used less or more sulfuric acid than examples 1 to 5, respectively; the activation time of comparative example 28 was longer than that of examples 1-5; the relevant detailed parameters for comparative examples 22-28 are given in table 7.

TABLE 5 summary of relevant detailed parameters for comparative examples 10-15

TABLE 6 detailed parameters relating to comparative examples 16 to 21

TABLE 7 detailed parameters relating to comparative examples 22-28

The plated products obtained in comparative examples 10 to 28 exhibited flow marks, oxidation, deformation, color difference, bubbling, peeling, plating unevenness, rust, and the like to various degrees. Referring to Table 5, the amount of sodium persulfate in the agent A used in comparative examples 10 and 11 is less than or more than the amount of sodium persulfate in the agent A used in examples 1 to 5, respectively, sodium persulfate, in combination with iron oxide and a nonionic surfactant, can efficiently remove an oxide layer from the surface of a copper alloy article to be plated, sodium persulfate can increase the metal surface roughness of the copper alloy article to be plated, thereby improving the metal surface binding force of the plating layer and the copper alloy part to be electroplated, the sodium persulfate is too little to be beneficial to removing the oxide layer, the sodium persulfate has strong oxidizing property, therefore, too much sodium persulfate can corrode the metal surface of the copper alloy part to be electroplated, but the metal surface roughness of the copper alloy part to be electroplated is too large, therefore, the binding force of the plating layer and the metal surface of the copper alloy part to be electroplated is not increased, and the phenomena of peeling, color difference and the like are easy to occur.

The dosage of the sodium chloride in the agent A used in the comparative examples 12 and 13 is respectively less than or more than that in the agent A used in the examples 1 to 5, the removal of an oxide layer, a microscopic protrusion point, a rusty substance and the like on the surface of a copper alloy part to be electroplated can be accelerated by matching chloride ions with sulfuric acid and sodium persulfate, after the oxide layer of the copper alloy part to be electroplated is removed, metal on the surface of the copper alloy part to be electroplated is in a naked state and is relatively easy to oxidize, a compact oxide film is formed on the surface of the metal by matching with a non-ionic surfactant due to the existence of a small amount of chloride ions, the rapid formation of the oxide film is not facilitated by too much chloride ions, the formed oxide film is destroyed and decomposed by too much chloride ions, and the purpose of efficiently removing the oxide scale, the microscopic protrusion point, the rusty substance or other dirt on the surface of the copper alloy part to be.

The dosage of citric acid in the agent A used in the comparative examples 14 and 15 is respectively less than or more than that of citric acid in the agent A used in the examples 1 to 5, the metal surface of the copper alloy electroplated part is in an activated state by the synergistic action of a small amount of citric acid and sulfuric acid, so that the bonding force of a plating layer and metal is ensured, the maintenance of the activated state of the metal surface is not facilitated by too little citric acid, the activation is insufficient, the surface roughness of the copper alloy electroplated part is increased, the citric acid is easily corroded to the metal surface too much, and the surface roughness of the copper alloy electroplated part is also easily increased.

Referring to table 6, the dosage of urea in the agent a used in comparative example 16 and comparative example 17 is respectively less than or more than that in the agent a used in examples 1 to 5, and urea is used for reducing the corrosion rate in a metal corrosion medium, so as to ensure that the copper material and the copper alloy material are not seriously corroded, and too little dosage of urea aggravates the corrosion rate of acid in the activation solution on the metal surface, so that the corrosion is excessive, the surface roughness of the copper alloy part to be electroplated is increased, the activation time is prolonged too much, the removal efficiency of the oxide layer is poor, and the practical application and production are not facilitated.

The dosage of the nonionic surfactant in the agents B used in the comparative examples 18 and 19 is respectively less than or more than that of the nonionic surfactant in the agents B used in the examples 1 to 5, the nonionic surfactant is used for reducing the surface tension of water and can rapidly penetrate between the metal surface and the oxide layer of the copper alloy part to be electroplated, other components are driven to penetrate to the metal surface together to enable the oxide layer to be self-stripped, the removal of the oxide layer, microscopic salient points, rusty objects and the like on the surface of the copper alloy part to be electroplated is accelerated by the synergistic effect of a small amount of chloride ions, sulfuric acid and sodium persulfate, the removal efficiency of the oxide layer is reduced by too little nonionic surfactant, and the corrosion to the metal surface is caused by too much nonionic surfactant, so that the surface roughness of the copper alloy part to be electroplated is increased.

The dosage of the iron oxide in the agent B used in the comparative examples 20 and 21 is respectively less than or more than that of the iron oxide in the agent B used in the examples 1 to 5, the iron oxide is matched with sodium persulfate and a nonionic surfactant to enable the metal surface of a copper alloy part to be electroplated to be smoother, so that the effects of brightening, grinding and leveling are achieved, and the insufficient iron oxide is not beneficial to leveling the metal surface, so that the activation is insufficient; excessive iron oxide generates excessive metal surface grinding, and the surface roughness of the copper alloy part to be electroplated is increased.

Referring to Table 7, the dosage of the agent A used in comparative examples 22 and 23 is less than or more than that used in examples 1 to 5, respectively, the dosage of the agent A is too small to facilitate the removal of the oxide layer, and the dosage of the agent A is too large to corrode the metal surface and erode excessively, which results in the electroplated part of the copper alloy.

The dosage of the agent B used in the comparative examples 24 and 25 is respectively less than or more than that of the agent B used in the examples 1-5, the dosage of the agent B is too small to affect the effect of the agent A, and the excessive grinding of the excessive dosage of the agent B can cause the problem of excessive corrosion of the metal surface, so that the surface roughness of the electroplated product is not in accordance with the production requirement.

The amount of sulfuric acid used in comparative examples 26 and 27 was less than or more than that used in examples 1 to 5, respectively, and the higher the sulfuric acid content, the faster the reaction speed, and the better the brightness, but too high an amount was less effective in dissolving the oxide layer; when the content of sulfuric acid is low, the reaction speed is reduced, so that the electroplated product is dark, and the production requirements are not met.

The activation time of the comparative example 28 is longer than that of the examples 1 to 5, the activation time is too long, not only can the metal surface be corroded, but also the consumption of the agent A, the agent B and the sulfuric acid is a waste of resources, meanwhile, the working efficiency is influenced by too long activation time, and the production line is difficult to apply.

Example 16

Poor crust breaking of an electroplated layer of an electroplated product is a common fault and has many reasons, such as oil stains on the surface of a copper alloy part to be electroplated are not completely removed during washing, oil removing powder is remained on the surface of the copper alloy part to be electroplated, or the activation effect is not ideal, so that the crust breaking phenomenon of the electroplated product can occur during a bending test or a grid drawing test, namely, the electroplated product cannot bear certain stress and crust breaking occurs.

Example 16 differs from example 1 in that: the copper alloy to-be-electroplated part can generate a plating layer skin cracking phenomenon when a bending test or a lattice test is carried out. The effect of the copper alloy used in example 16 after activation of the article to be plated is also shown in FIG. 2. See table 8 for relevant detailed parameters and results.

Comparative examples 29 to 30

Comparative examples 29 to 30 differ from example 16 in that: the copper alloy to be electroplated member used has different components of the activating solution used in the activating step. That is, the activating solution used in comparative example 29 contains sulfuric acid at a volume concentration of 100mL/L, the activating solution used in comparative example 30 is commercially available, and the main components of the activating solution used in comparative example 30 are ammonium bifluoride, sodium persulfate, potassium permanganate, and sodium bisulfate. See table 8 for relevant detailed parameters and results.

TABLE 8 comparative results of comparative examples 29 to 30 and example 17 for peeled copper alloy workpieces to be electroplated

Referring to table 8, in example 16, the activating solution of the present application has a good prevention effect on the plated products which are prone to the peeling phenomenon, successfully solves the problem that the copper material or the copper alloy material is prone to peeling, can be stably and continuously produced for more than 36 hours without replacing the activating solution, and is low in production cost and beneficial to popularization and application. The comparative example 29 and the comparative example 30 adopting the other activating solution have the defects that the problem that the copper material or the copper alloy material is easy to peel is difficult to improve, particularly the comparative example 30 has the defects that the production process is very unstable, the activating solution needs to be replaced every 4 hours to ensure the activating effect, the quality of the electroplated product is unstable, and the phenomenon of insufficient activation or excessive etching appears at intervals of the electroplated product.

Performance test

1. Adhesion test

(1) The plated products obtained in examples 1 to 16 and comparative examples 1 to 30 were subjected to a cross-hatch test: step one, placing a plated product in an environment with the temperature of 260 +/-10 ℃ for baking for 5 minutes, cooling, and then respectively scribing hundreds of grids on two sides of an electroplating material belt by using a cutter;

step two, pasting the hundred-grid-scribed part in a manner of laminating one layer by using masking tape, and pressing the hundred-grid-scribed part with force after pasting;

and step three, pressing the plated product with one hand, and quickly tearing off the masking tape with the other hand. And repeating the second step and the third step and observing the coating falling phenomenon under a microscope.

(2) Bending test: firstly, a copper sheet with the same thickness as a terminal to be detected is padded at a position, needing to be bent, of an electroplating product, a sample is bent to 180 degrees by using flat tongs, and whether a plating layer on a bent surface peels off or not is observed under a microscope.

After the cross cut test and the bending test, the results of the adhesion test of the plated products of examples 1 to 16 are shown in FIG. 6, and the results of the adhesion test of the plated products of comparative examples 1 to 30 are shown in FIG. 7. As can be seen from FIG. 6, the copper alloy objects to be plated of examples 1 to 16 are excellent in the bonding force with the plating layer. As can be seen from FIG. 7, the copper alloy objects to be plated of comparative examples 1 to 30 had poor adhesion to the plating layer and had a plating layer peeling phenomenon.

2. Baking test

The plated products obtained in examples 1 to 16 and comparative examples 1 to 30 were each baked for 3H in an environment at a temperature of 180 ℃, and after baking was completed, it was observed under a microscope whether or not there was a blister or discoloration. The test results showed that the plated products of examples 1 to 16, comparative examples 4, 7, 12 and 29 were free from bubbles and discoloration, while the plated products of comparative examples 1 to 3, 5 to 6, 8 to 11, 13 to 29 and comparative example 30 were variously foamed, whitened and peeled, and the quality of the plated products was greatly reduced.

3. Immersion tin test

The plated products obtained in examples 1 to 16 and comparative examples 1 to 30 were placed in tin solutions in a tin furnace at a temperature of 260. + -. 5 ℃ for 3 to 5 seconds, taken out, and the tin-stained areas of the plating layers were observed under a microscope and recorded.

The test results show that the tin-adhering surface area of the electroplated products of examples 1-16 is not less than 95%, i.e., the bonding force between the copper alloy to-be-plated parts and the plating layers of examples 1-16 is excellent. The tin-sticking surface areas of the electroplated products of the comparative examples 1 to 30 are less than 90%, namely the bonding force between the copper alloy to-be-plated piece and the plating layer of the comparative examples 1 to 30 is poor.

The above embodiments are preferred embodiments of the present application, and the protection scope of the present application is not limited by the above embodiments, so: all equivalent changes made according to the structure, shape and principle of the present application shall be covered by the protection scope of the present application.

Claims

1. A method for carrying out surface activation treatment on the surface of a copper alloy is characterized by comprising the following steps: the method comprises the following steps: 1) carrying out electrolytic degreasing and water washing on a copper alloy part to be electroplated; 2) conveying the copper alloy to-be-electroplated part subjected to electrolytic degreasing and water washing into an activating solution and activating at room temperature; the activating solution is prepared from the following components: the dosage of the agent A is 45-50g/L, B, the dosage is 0.2-0.8mL/L, and the dosage of the sulfuric acid is 2-8 mL/L; wherein the agent A is prepared from the following components in percentage by volume: 70-90% of sodium persulfate, 0.5-5% of sodium chloride, 5-15% of citric acid and 4-10% of urea; the agent B is prepared from the following components in percentage by volume: 2-6% of nonionic surfactant, 35-54% of ferric oxide and 40-60% of deionized water; 3) and (4) washing and drying the copper alloy to-be-electroplated part after activation to obtain an electroplated product.

2. The method of claim 1, wherein the surface activation treatment is performed on the surface of the copper alloy by: the pH value of the activating solution is 1-4.

3. The method of claim 2, wherein the step of performing surface activation treatment on the copper alloy surface comprises: the activation time is 3-45 s.

4. The method of claim 3, wherein the step of performing surface activation treatment on the copper alloy surface comprises: the temperature required for activation is 25-50 ℃.

5. The method of claim 4, wherein the step of activating the surface of the copper alloy further comprises: electrolytic degreasing is carried out on a copper alloy part to be electroplated in degreasing liquid, the degreasing liquid comprises degreasing powder with the concentration of 60-90g/L, and the baume degree of the degreasing liquid is 4-12 DEG Be.

6. The method of claim 5, wherein the step of performing surface activation treatment on the copper alloy surface comprises: the current required by electrolytic degreasing is 20-60A.

7. The method of claim 1, wherein the surface activation treatment is performed on the surface of the copper alloy by: the electrolytic degreasing time is 10-60 s.

8. The method of claim 7, wherein the step of activating the surface of the copper alloy further comprises: electrolytic degreasing is carried out at room temperature.