CN111167686A

CN111167686A - Long-acting anticorrosive coating on copper alloy surface and preparation method thereof

Info

Publication number: CN111167686A
Application number: CN201910778297.7A
Authority: CN
Inventors: 刘少通; 高磊; 郭为民; 邱日; 马力; 彭文山
Original assignee: 725th Research Institute of CSIC
Current assignee: 725th Research Institute of CSIC
Priority date: 2019-08-22
Filing date: 2019-08-22
Publication date: 2020-05-19

Abstract

The invention provides a long-acting anticorrosive coating on the surface of a copper alloy and a preparation method thereof, wherein the long-acting anticorrosive coating comprises a substrate and an anticorrosive coating on the surface of the substrate, the anticorrosive coating comprises a Cu pre-oxidation coating deposited on the surface of the substrate and an oleic acid layer filled in the Cu pre-oxidation coating and on the surface of the Cu pre-oxidation coating, and the preparation method of the anticorrosive coating comprises the following steps: 1) preparing a copper electrode sample; 2) surface pretreatment of a copper electrode sample; 3) pre-oxidizing and depositing oleic acid on the surface of a copper electrode sample to prepare a copper alloy anticorrosive coating, wherein the step 3) is as follows: a copper electrode sample is taken as a substrate, firstly, a nano Cu structure is electrodeposited on a bare copper substrate, secondly, the nano Cu structure is oxidized, and finally, oleic acid is injected into the surface of the oxidized substrate, and the surface is placed in an oven to be kept at a constant temperature for 8-12 h to form a copper alloy anticorrosive coating. The surface contact angle of the anticorrosive coating is 100.2 degrees, the coating shows super-hydrophobicity, and meanwhile, the coating has good mechanical property, and even if the coating is damaged to a certain degree, the coating still can keep good corrosion resistance.

Description

Long-acting anticorrosive coating on copper alloy surface and preparation method thereof

Technical Field

The invention belongs to the field of metal corrosion protection, and particularly relates to a preparation method of an oxide film on the surface of a copper alloy and a method for realizing long-term corrosion prevention of the copper alloy by using the oxide film as an anticorrosive layer.

Background

Copper and copper alloy have good seawater corrosion resistance and marine biofouling resistance, and are widely applied to marine engineering. However, if the copper alloy equipment is not subjected to surface treatment, accidents can be caused by corrosion problems in the service process of the seawater environment. The normal use of equipment is seriously influenced by seawater corrosion, the attendance rate of ship equipment is reduced, and accident potential is caused. In addition, the copper alloy surface is subjected to physical abrasion in a marine environment, so that the surface coating is damaged, and the marine condenser pipe is severely corroded when used in a seawater environment with high sand content in the east sea area. Therefore, there is a need to design a corrosion-resistant and wear-resistant copper alloy surface treatment technology to provide a technical support for solving the environmental corrosion problem of the copper alloy.

Disclosure of Invention

The technical task of the invention is to provide a corrosion-resistant copper alloy anticorrosive coating aiming at the corrosion problem of copper in seawater in the prior art, and simultaneously, in order to avoid the physical damage of the coating in the using process, the coating is designed to have good mechanical property; ensures that the coating can still maintain good corrosion resistance even if the coating is damaged to a certain degree.

The technical scheme adopted by the invention for solving the technical problems is as follows:

1. the invention provides a long-acting anticorrosive coating on the surface of a copper alloy, which comprises a substrate and an anticorrosive coating on the surface of the substrate, wherein the anticorrosive coating comprises a Cu pre-oxidation coating deposited on the surface of the substrate and an oleic acid layer filled in the Cu pre-oxidation coating and on the surface of the Cu pre-oxidation coating,

the preparation method of the anticorrosive coating comprises the following steps: 1) preparing a copper electrode sample; 2) surface pretreatment of a copper electrode sample; 3) pre-oxidizing and depositing oleic acid on the surface of a copper electrode sample to prepare a copper alloy anticorrosive coating, wherein the step 3) is as follows: a copper electrode sample is taken as a substrate, firstly, a nano Cu structure is electrodeposited on a bare copper substrate, secondly, the nano Cu structure is oxidized, and finally, oleic acid is injected into the surface of the oxidized substrate, and the surface is placed in an oven to be kept at a constant temperature for 8-12 h to form a copper alloy anticorrosive coating.

2. The invention also provides a preparation method of the long-acting anticorrosive coating on the surface of the copper alloy, which comprises the following steps: 1) preparing a copper electrode sample; 2) surface pretreatment of a copper electrode sample; 3) pre-oxidizing and depositing oleic acid on the surface of a copper electrode sample to prepare a copper alloy anticorrosive coating,

wherein step 3) means: a copper electrode sample is taken as a substrate, firstly, a nano Cu structure is electrodeposited on a bare copper substrate, secondly, the nano Cu structure is oxidized, and finally, oleic acid is injected into the surface of the oxidized substrate, and the surface is placed in an oven and kept at a constant temperature for 10 hours to form a copper alloy anticorrosive coating.

Preferably, the step 3) specifically comprises the following steps:

3.1) carrying out electrochemical deposition by adopting an electrochemical testing system, wherein a three-electrode system is adopted in the experiment, and the electrolyte is 0.05-0.15M CuCl₂•6H₂O and 0.05-0.15M Na₂SO₄Electrodepositing the mixed solution for 500-700 s under the voltage of-500 to-700 mV to form a dendritic structure on the surface of the sample;

3.2) immediately taking out the sample after the electrodeposition is finished, cleaning the surface by using deionized water and ethanol in sequence, and placing the sample in an oven to be dried at the temperature of 30-45 ℃;

3.3) then soaking the sample prepared in the step 3.2) in NaOH with the concentration of 2-4M and 0.05-0.15M (NH4)₂S₂O₈Oxidizing the sample in the oxidizing solution for 400-600 s to form a loose nano needle-like structure on the surface of the sample, then slightly washing the surface of the oxidized sample by ethanol, and placing the sample in an oven at 30-45 DEG^oC, drying;

3.4) dropwise adding a proper amount of oleic acid on the surface of the sample until the surface is completely covered, and then inclining the sample to enable the redundant oleic acid to freely flow out under the action of gravity;

3.5) finally placing the sample in an oven, adjusting to 50-90 DEG^oAnd C, drying for 10 h to obtain the copper alloy anticorrosive coating.

Preferably, the step 1) specifically comprises the following steps:

1.1) welding a copper block by using a copper wire and detecting conductivity, then vertically placing a working surface of a sample with the size of 10 mm multiplied by 10 mm along a phi 20PVC pipe, ensuring that the bottom surface is level, and sealing the working surface by using GOET-1080RL transparent tough epoxy resin pouring sealant (the proportion of AB components is 5: 2) to ensure that the working surface is not contacted with the epoxy resin;

and 1.2) placing the sealed sample in an oven, keeping the temperature of 60 ℃ constant for 6 h, naturally cooling to room temperature, and completely curing resin to obtain the copper electrode sample.

Preferably, the step 2) specifically comprises the following steps:

and taking out the cured sample, and polishing the exposed working surface by using 240-mesh, 500-mesh to 800-mesh silicon carbide sand paper step by step. Cleaning the surface of the polished sample with ultrapure water and ethanol in sequence, and placing the sample in an oven at 30-45 DEG^oAnd C, drying.

Preferably, in step 3), the three-electrode system uses a pure copper sample as a working electrode, a saturated potassium chloride calomel electrode as a reference electrode and a platinum wire as a counter electrode.

Preferably, in step 3.1), during electrochemical deposition, the electrolytic device is placed in a shielding box for deposition experiment.

Compared with the prior art, the long-acting anticorrosive coating on the surface of the copper alloy and the preparation method thereof have the beneficial effects that:

the method takes a copper electrode sample as a substrate, firstly electrodeposits a nano Cu structure on a bare copper substrate, secondly oxidizes the nano Cu structure, and finally injects oleic acid into the surface of the oxidized substrate to keep the temperature of an oven constant for 10 hours to form a complete coating, wherein the surface contact angle of the anticorrosive coating is 100.2^oShows super-hydrophobicity, and simultaneously has good mechanical property, even if certain damage occurs, the coating still canAnd good corrosion resistance is maintained.

Drawings

FIG. 1 is a schematic diagram of a method for preparing a coating by combining electrodeposition, oxidation and oleic acid injection steps according to the present invention;

fig. 2 is a two-dimensional (b) and three-dimensional (c) image of the height difference of the joint region between the original Cu and the electrodeposited Cu surface of the present invention. (d) Height maps of the original Cu and electrodeposited metal Cu surface cross sections;

FIG. 3 is an electron microscope image (d-f) of the oxidized form of the nano dendritic copper after the nano dendritic copper is electrodeposited on the surface of the metal copper in the invention (a-c);

FIG. 4 shows the elements and contents before and after the oxidation of (a) the metal copper surface electrodeposition nano dendritic copper and the oxidation XRD (b and c) nano dendritic copper;

FIG. 5 shows the size of the contact angle during the coating preparation process of the present invention (a) bare copper (b) surface electrodeposited nano dendritic copper (c) contact angle after oxidation of nano dendritic copper (d) contact angle after oxidation of nano dendritic copper in combination with oleic acid after reaction at high temperature;

FIG. 6 shows the change law of (a) electrochemical impedance spectrum and (b) polarization curve of copper hydroxide and oleic acid coating prepared at different temperatures;

FIG. 7 shows copper hydroxide and oleic acid at 80 deg.C^oAnd (C) the electrochemical impedance spectrum (a) and the polarization curve (b) of the coating prepared under the condition of mechanical property test.

Detailed Description

The long-acting anticorrosive coating on the surface of copper alloy and the preparation method thereof are described in detail below with reference to the accompanying drawings 1 to 7.

Example one

1. Long-acting anticorrosive coating on copper alloy surface and preparation thereof

The invention discloses a long-acting anticorrosive coating on the surface of a copper alloy, which comprises a substrate and an anticorrosive coating on the surface of the substrate, wherein the anticorrosive coating comprises a Cu pre-oxidation coating deposited on the surface of the substrate and an oleic acid layer filled in the Cu pre-oxidation coating and on the surface of the Cu pre-oxidation coating, and the preparation method of the anticorrosive coating comprises the following steps:

1) preparation of copper electrode samples

Welding a copper block by using a copper wire and detecting conductivity, vertically placing a working surface of a sample with the size of 10 mm multiplied by 10 mm along a phi 20PVC pipe, ensuring that the bottom surface is level, and sealing the working surface by using a GOET-1080RL transparent tough epoxy resin pouring sealant (the AB component distribution ratio is 5: 2) so that the working surface is not contacted with epoxy resin;

and (3) placing the sealed sample in an oven, keeping the working temperature at 60 ℃ for 6 h, naturally cooling to room temperature, and completely curing the resin to obtain the copper electrode sample.

2) Surface pretreatment of copper electrode samples

And taking out the cured sample, and polishing the exposed working surface by using 240-mesh, 500-mesh to 800-mesh silicon carbide sand paper step by step. And cleaning the surface of the polished sample by ultrapure water and ethanol in sequence, and drying the sample in an oven at 40 ℃.

3) Copper alloy anticorrosive coating prepared by preoxidation deposition of oleic acid on surface of copper electrode sample

An electrochemical testing system is adopted for carrying out chemical deposition to prepare the coating, a three-electrode system is adopted in the experiment, a pure copper sample is taken as a working electrode, a saturated potassium chloride calomel electrode is taken as a reference electrode, and a platinum wire is taken as a counter electrode. The electrolyte is 0.1M CuCl₂.6H₂O and 0.1M Na₂SO₄The solution was mixed and the electrolytic device was placed in a shielded box for deposition experiments. Electrodepositing for 600 s at-600 mV,

and (3) immediately taking out the sample when the deposition is finished, cleaning the surface by using deionized water and ethanol in sequence, and drying the sample in an oven at 40 ℃.

The prepared sample was then soaked in 2.5M NaOH and 0.1M (NH4)₂S₂O₈The surface of the sample is oxidized for 500 s from dark red to blue in the oxidation process, and then the oxidized surface is lightly washed by ethanol and is dried in an oven at 40 ℃.

Then, a proper amount of oleic acid is dripped on the surface of the sample until the surface is completely covered, then the sample is inclined for 45 degrees, so that the redundant oleic acid freely flows out under the action of gravity,

and finally, placing the sample in an oven, and drying for 10 hours by distributing and adjusting to different temperatures (50 ℃, 60 ℃, 70 ℃, 80 ℃ and 90 ℃). The prepared samples were stored in a drying dish for further experiments.

Material structural testing and characterization

Observing the original Cu and the surface micro-topography characteristics after oxidation by adopting a field emission scanning electron microscope; analyzing the surface components of the oxidized Cu by adopting an energy scattering spectrum; analyzing the oxidized surface product by using X-ray diffraction; an optical three-dimensional microscope is used for revealing the shape change of the Cu surface and the electrodeposited nano Cu. FIG. 1 a is a schematic diagram showing the steps of preparing a coating, firstly electrodepositing a nano Cu structure on a bare copper substrate, secondly oxidizing the nano Cu structure, and finally injecting oleic acid on the surface of the oxidized substrate, placing the substrate in an oven, and keeping the temperature for 10 hours to form a complete coating; FIG. 2b is a two-dimensional image with the black portion being the prepared coating and the yellow-earth portion being the bare copper substrate; fig. 2 c shows a three-dimensional image of the coating structure, which can visually see the three-dimensional structure of the coating surface and what variation trend of the boundary, wherein the blue part is the right half part of the bare copper substrate 2b, the red yellow part is the coating part, and the boundary is caused by the adhesive tape bonding effect, so that the growth of the nano structure is not uniform; fig. 2 d, shows that the thickness of the coating is about 50 μm. As can be seen from FIGS. 3 a-d, the deposited nano-copper on the copper substrate is very uniform and dense, and the deposited nano-copper is shown to be dendritic when the thickness is enlarged to 1 μm. As shown in fig. 3 d-e, the oxidized morphology becomes nanosphere-like, and the nanospheres are composed of smaller-scale nanoneedles extending from the inside and having a length on the order of about 1-10 microns. Compared with a dendritic structure before oxidation, the nano needle-shaped structure is more loose, and the gap between the needles is larger, so that favorable conditions are further provided for injecting more oleic acid, and the oil storage capacity is greatly improved. FIG. 4 a is an XRD diffraction spectrum of an oxidation product of the electrodeposited nano dendritic copper oxidation liquid. The electro-deposited nano dendritic copper is gradually changed into grayish blue from dark red in the oxidizing solution, and the Cu (OH) on the surface of the original Cu can be preliminarily judged according to the phenomenon₂And (4) forming. The resultant was analyzed by X-ray diffraction to reveal Cu (OH)₂Physical phaseCharacteristic peaks (020), (021), (002), (111), (022), (130), (150) and (171) of (g), and at the same time peaks of Cu metal can also be found. (JCPDS No. 12-420) As can be seen from FIGS. 3b and 3 c, the change in the elemental content before and after oxidation is most pronounced O, Cu, with an increase in the elemental content of O from about 4.2% to about 35.0% and a corresponding decrease in the elemental content of Cu of about 64.4%, as compared to Cu (OH)₂The close ratio of Cu to O in the material (about 65.1 and 32,.8, respectively) indirectly indicates that Cu (OH) is formed during the oxidation process₂。

Material performance testing and characterization

The surface wettability was measured at room temperature (25 ℃) using a static contact angle measuring instrument (contact angle measurement was performed with the platform kept level with the sample surface, contact angle test was performed at random portions of bare Cu and oxidized surface, 10 or more times per data, fig. 5 shows wettability of the surface at different stages in the coating preparation process, fig. 5 a shows that the static contact angle of the surface with a water drop is about 98.5 ° for bare copper, after electrodeposition of a nano dendritic copper surface on a metallic Cu surface, the contact angle is reduced to 27.8 ° (fig. 5 b) because the deposited nano dendritic, multi-slit (fig. 3 b) makes the water molecules easily immerse, resulting in a more pronounced hydrophilic effect and thus a correspondingly greater increase in wettability than bare copper, fig. 5C shows the surface wettability after nano dendritic oxidation, when the water drop is on the surface, the water drop can be completely spread and covered on the matrix, the super-hydrophilic contact angle is 0 degrees, the complete wetting is shown, because the surface appearance after oxidation is in a loose needle point shape (figure 3 f), and the pores are further increased compared with the dendritic shape. Fig. 5 (d) is a contact angle of 100.2 ° after injecting oleic acid into the oxidized surface and heating at a high temperature, because oleic acid replaces air stored in the nanoporous structure, and the binding force of oleic acid with water molecules is weak, making it difficult for water molecules to enter the voids.

Open Circuit Potential (OCP), Electrochemical Impedance (EIS) and polarization curve (Tafel) tests were performed on coatings prepared at different temperatures using an electrochemical testing system. The electrochemical test uses a standard three-electrode system, the prepared coating sample is a working electrode, and saturated chlorination is carried outThe potassium calomel electrode (SCE) was used as a reference electrode and the platinum/niobium wire as an auxiliary electrode, except where specifically noted, the electrochemical standards of this patent were tested based on SCE. The electrolyte solution used in the electrochemical test experiment was natural seawater (Qingdao N36)^o19^”E120^o41') before testing the electrochemical data, firstly, placing the sample in seawater to soak for 20 min, detecting whether the open-circuit potential is stable, and testing the impedance and polarization curve under the condition that the open-circuit potential is stable. EIS adopted 10⁵-10^-2Hz frequency range, amplitude is + -10 mV relative to open circuit potential, and 51 measurement record points are recorded. And analyzing the data result obtained by the test by using fitting software ZsimpWin. When the potentiodynamic polarization test is carried out, the scanning range is +/-250 mV relative to the open circuit potential, and the scanning speed is 1.667 mV/s. The corrosion resistance effect of the coatings prepared at different temperatures was compared using Electrochemical Impedance Spectroscopy (EIS). As shown in FIG. 5 a, the resistance of bare copper is about 1.62X 10³Ω·cm^-2Z at 50 ℃ and 60 ℃ as the reaction temperature of copper hydroxide and oleic acid increases_0.01HZThe impedance is about 1.14 × 10⁴Ω·cm^-2And 1.86X 10⁴Ω·cm^-2The low-frequency impedance value is improved by 1 order of magnitude; the resistance of the coating was about 1.32X 10 at a temperature of 70 DEG C⁶Ω·cm^-2The impedance is improved by about 3 orders of magnitude compared with that of bare copper; the temperature is 80 ℃, and the impedance value is as high as 8.81 multiplied by 10⁷Ω·cm^-2The low frequency impedance is improved by 4 orders of magnitude compared with that of bare copper. But increases with temperature to 90 ℃ (Z)_0.01HzAbout 1.51X 10⁷Ω·cm^-2) The impedance does not increase all the time, but instead decreases by a factor of 5.8 from 80 ℃. Reveals that the coating prepared at 80 ℃ has good anti-corrosion effect.

The corrosion protection effect is further illustrated by comparing the corrosion potential and the corrosion current density using the polarization curve technique, as shown in FIG. 6 b and Table 1, the self-corrosion current density is found to be 9.68X 10 during the temperature range from 50 ℃ to 70 ℃^-3mA/cm²Gradually decreases to 1.58 × 10^-5mA/cm²When the temperature is increased to 80 ℃ (2.88X 10)^-7mA/cm²) And 90 ℃ (4.54 × 10)^-6mA/cm²) The former is found to have the most obvious decrease of self-corrosion current density, which is respectively compared with bare copper (2.36 multiplied by 10)^-2mA/cm²) And 5 and 4 orders of magnitude smaller, as shown in fig. 6a, the low frequency impedance of the coating prepared at 80 ℃ is the largest, and the self-corrosion current density is the smallest.

TABLE 1 FIG. 6 polarization curve fitting results

	E_corr(mV)	I_corr(mA/cm²)	β_a(mV/decade)	-β_c(mV/decade)
					Bare copper	-237.19	9.36×10^-2	454.45	203.90
50°C	-182.33	9.68×10^-3	630.06	119.31
					60°C	-243.58	1.34×10^-4	147.34	209.64
70°C	-176.59	1.58×10^-5	111.39	854.61
					80°C	-94.737	2.88×10^-7	602.87	189.97
90°C	-119.69	4.54×10^-6	258.96	258.94

The mechanical property test adopts a coating sample prepared under the condition of constant temperature of 80 ℃, each sample is repeated for at least three times to ensure the accuracy of data, the manual cutting experiment is respectively carried out on the samples, and the cutting experiments are respectively carried out for 10, 20, 30, 40 and 50 times on different samples. Electrochemical impedance and polarization curve tests were then performed. The electrochemical test still adopts a three-electrode system, and the electrolyte solution used in the electrochemical test experiment is natural seawater under the same conditions. As shown in fig. 7 a, we performed mechanical property tests on the coating, and performed different knife-cut mechanical failure tests on the coating, at least three times per test. Specimen Z before testing_{0.01 Hz}About 1.50X 10⁷Ω·cm^-2The impedance gradually decreased with the knife cut damage to the coating, and we found that the low frequency impedance remained at 9.55 x 10 despite 40 knife cut failures⁵Ω·cm^-2Still lower frequency impedance than bare copper (1.62X 10, FIG. 6 a)³Ω·cm^-2) Approximately two orders of magnitude. FIG. 7 b and Table 2 show polarization curves with increasing self-etching current density from 1.78X 10^-4mA/cm²Increased to 9.90 × 10^-2mA/cm². The self-corrosion current density after 35 times of manual cutting is about 1/5 of that of the bare copper.

TABLE 2 FIG. 7 polarization curve fitting results

	E_corr(mV)	I_corr(mA/cm²)	β_a(mV/decade)	-β_c(mV/decade)
					0	-72.56	1.87×10^-5	362.46	403.81
14	-199.70	1.78×10^-4	456.77	394.92
					28	-204.82	5.90×10^-3	251.92	569.15
35	-208.58	1.90×10^-2	275.72	369.43

Example two

1) preparation of copper electrode samples

2) Surface pretreatment of copper electrode samples

And taking out the cured sample, and polishing the exposed working surface by using 240-mesh, 500-mesh to 800-mesh silicon carbide sand paper step by step. And cleaning the surface of the polished sample by ultrapure water and ethanol in sequence, and drying the sample in an oven at 30 ℃.

3) Surface coating preparation of copper electrode sample

An electrochemical testing system is adopted for carrying out chemical deposition to prepare the coating, a three-electrode system is adopted in the experiment, a pure copper sample is taken as a working electrode, a saturated potassium chloride calomel electrode is taken as a reference electrode, and a platinum wire is taken as a counter electrode. Electrolyte is 0.05M CuCl₂.6H₂O and 0.05M Na₂SO₄The solution was mixed and the electrolytic device was placed in a shielded box for deposition experiments. Electrodepositing for 700 s at a voltage of-500 mV,

and (3) immediately taking out the sample when the deposition is finished, cleaning the surface by using deionized water and ethanol in sequence, and drying the sample in an oven at the temperature of 30 ℃. The prepared sample was then soaked in NaOH solution at a concentration of 2M and 0.05M (NH4)₂S₂O₈The surface of the sample is oxidized for 400 s from dark red to blue in the oxidation process, and then the oxidized surface is lightly washed by ethanol and is dried in an oven at 30 ℃.

and finally, placing the sample in an oven, and drying for 8 hours by distributing and adjusting to different temperatures (50 ℃, 60 ℃, 70 ℃, 80 ℃ and 90 ℃). The prepared samples were stored in a drying dish for further experiments.

The material structure test and characterization, and the material performance test and characterization are the same as the examples.

EXAMPLE III

1) preparation of copper electrode samples

2) Surface pretreatment of copper electrode samples

And taking out the cured sample, and polishing the exposed working surface by using 240-mesh, 500-mesh to 800-mesh silicon carbide sand paper step by step. And cleaning the surface of the polished sample by ultrapure water and ethanol in sequence, and drying the sample in an oven at 45 ℃.

3) Surface coating preparation of copper electrode sample

An electrochemical testing system is adopted for carrying out chemical deposition to prepare the coating, a three-electrode system is adopted in the experiment, a pure copper sample is taken as a working electrode, a saturated potassium chloride calomel electrode is taken as a reference electrode, and a platinum wire is taken as a counter electrode. The electrolyte is 0.15M CuCl₂.6H₂O and 0.15M Na₂SO₄The solution was mixed and the electrolytic device was placed in a shielded box for deposition experiments. Electrodepositing for 500 s at a voltage of-700 mV,

and (3) immediately taking out the sample when the deposition is finished, cleaning the surface by using deionized water and ethanol in sequence, and drying the sample in an oven at the temperature of 45 ℃. The prepared sample was then soaked in NaOH solution at a concentration of 4M and 0.15M (NH4)₂S₂O₈The surface of the sample is changed from dark red to blue in the oxidation process for 600 s, and then the oxidized surface is lightly washed by ethanol and is dried in an oven at 45 ℃.

and finally, placing the sample in an oven, and drying for 12 h by distributing and adjusting to different temperatures (50 ℃, 60 ℃, 70 ℃, 80 ℃ and 90 ℃). The prepared samples were stored in a drying dish for further experiments.

Example four

1) preparation of copper electrode samples

2) Surface pretreatment of copper electrode samples

And taking out the cured sample, and polishing the exposed working surface by using 240-mesh, 500-mesh to 800-mesh silicon carbide sand paper step by step. And cleaning the surface of the polished sample by ultrapure water and ethanol in sequence, and placing the sample in an oven to be dried at 35 ℃.

3) Surface coating preparation of copper electrode sample

An electrochemical testing system is adopted for carrying out chemical deposition to prepare the coating, a three-electrode system is adopted in the experiment, a pure copper sample is taken as a working electrode, a saturated potassium chloride calomel electrode is taken as a reference electrode, and a platinum wire is taken as a counter electrode. The electrolyte is 0.12M CuCl₂.6H₂O and 0.12M Na₂SO₄The solution was mixed and the electrolytic device was placed in a shielded box for deposition experiments. Electrodepositing for 500 s at a voltage of-650 mV,

and (3) immediately taking out the sample when the deposition is finished, cleaning the surface by using deionized water and ethanol in sequence, and drying the sample in an oven at 35 ℃. The prepared sample was then soaked in 2.2M NaOH and 0.12M (NH4)₂S₂O₈Oxidizing the surface of the sample from dark red to blue in the oxidizing solution for 450 s, then slightly washing the oxidized surface with ethanol and placing the surfaceDrying in an oven at 35 ℃.

and finally, placing the sample in an oven, and drying for 9 h by distributing and adjusting to different temperatures (50 ℃, 60 ℃, 70 ℃, 80 ℃ and 90 ℃). The prepared samples were stored in a drying dish for further experiments.

While the preferred embodiments of the present application have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all alterations and modifications as fall within the scope of the application.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present application without departing from the spirit and scope of the application. Thus, if such modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is intended to include such modifications and variations as well.

In addition to the technical features described in the specification, the technology is known to those skilled in the art.

Claims

1. A long-acting anticorrosive coating on the surface of a copper alloy comprises a substrate and an anticorrosive coating on the surface of the substrate, and is characterized in that the anticorrosive coating comprises a Cu pre-oxidation coating deposited on the surface of the substrate and an oleic acid layer filled in the Cu pre-oxidation coating and on the surface of the Cu pre-oxidation coating;

2. A preparation method of a long-acting anticorrosive coating on the surface of a copper alloy is characterized by comprising the following steps: 1) preparing a copper electrode sample; 2) surface pretreatment of a copper electrode sample; 3) pre-oxidizing and depositing oleic acid on the surface of a copper electrode sample to prepare a copper alloy anticorrosive coating,

3. The preparation method of the long-acting anti-corrosion coating on the surface of the copper alloy as claimed in claim 2, wherein the step 3) specifically comprises the following steps:

3.2) immediately taking out the sample when the electrodeposition is finished, cleaning the surface by using deionized water and ethanol in sequence, and placing the sample in an oven at 30-45 DEG^oC, drying;

3.5) finally placing the sample in an oven, adjusting to 50-90 DEG^oAnd C, drying for 8-12 h to obtain the copper alloy anticorrosive coating.

4. The preparation method of the long-acting anti-corrosion coating on the surface of the copper alloy as claimed in claim 2 or 3, wherein the step 1) specifically comprises the following steps:

5. The preparation method of the long-acting anti-corrosion coating on the surface of the copper alloy as claimed in claim 2 or 3, wherein the step 2) specifically comprises the following steps:

and taking out the solidified sample, polishing the exposed working surface by using 240-mesh, 500-mesh to 800-mesh silicon carbide abrasive paper step by step, cleaning the surface of the polished sample by using ultrapure water and ethanol in sequence, and placing the sample in an oven to be dried at the temperature of 30-45 ℃.

6. The method for preparing the long-acting anticorrosive coating on the surface of the copper alloy according to claim 2 or 3, wherein in the step 3), the three-electrode system uses a pure copper sample as a working electrode, a saturated potassium chloride calomel electrode as a reference electrode and a platinum wire as a counter electrode.

7. The method for preparing the long-acting anti-corrosion coating on the surface of the copper alloy as claimed in claim 2 or 3, wherein in the step 3.1), an electrolytic device is placed in a shielding box for deposition experiments during electrochemical deposition.