Self-sacrifice nanoparticle reinforced chemical deposition process for pitting corrosion inhibition of B30 copper-nickel alloy

Abstract

The invention provides a self-sacrifice nano-particle reinforced chemical deposition process for pitting corrosion inhibition of a B30 copper-nickel alloy, and belongs to the technical field of material surface protection. According to the method, the B30 copper-nickel alloy pipe is subjected to alkali washing and acid washing and then subjected to ultrasonic-assisted chemical nickel plating, the inner wall of the B30 copper-nickel alloy pipe is plated with a nano-particle reinforced composite plating layer, self-sacrifice nano-particle reinforcement of B30 copper-nickel alloy pitting corrosion inhibition is achieved, and a chemical plating solution used in the ultrasonic-assisted chemical nickel plating process is an acidic chemical nickel plating solution. According to the method, the potential of the coating is increased by adding the nanoparticles, and meanwhile, the potential of the coating is slightly lower than that of a B30 copper-nickel alloy substrate, so that the protection aging of the self-sacrifice coating is effectively prolonged, and the corrosion resistance of the coating is improved; according to the process, the consumption rate of the plating layer is obviously reduced, the wear resistance is greatly improved, and the process has important significance on pitting corrosion inhibition of the B30 copper-nickel alloy pipeline.

Description

Technical Field

[0001] The invention belongs to the technical field of material surface protection, and in particular relates to a self-sacrificial nanoparticle enhanced chemical deposition process for inhibiting pitting corrosion of B30 copper-nickel alloy. Background Art

[0002] B30 copper-nickel alloy pipe has the advantages of good seawater erosion corrosion resistance, high heat transfer coefficient and excellent anti-fouling performance. At present, with the continuous development of marine engineering, B30 alloy is widely used. However, with the reports of early damage accidents of B30 alloy pipelines, many studies have conducted in-depth research on the original surface film defects and organizational structure defects of the alloy. A large number of studies have found that when B30 copper-nickel alloy pipelines are in use, their erosion self-passivation performance creates excellent anti-corrosion performance, but there are pitting corrosion, crevice corrosion and other corrosion during the period of static water immersion, which has a great impact and harm.

[0003] The most effective way to solve alloy corrosion is to perform surface treatment on the material. This method can not only effectively improve the surface performance of the material and thus increase its service life, but also will not lead to a substantial increase in the cost of material and machinery manufacturing. It is a very economical and effective method to improve material performance. At present, the most widely used methods for alloy surface treatment are electroplating and chemical plating. Compared with electroplating, chemical plating does not require the use of electrodes or related power-on equipment. It is cheaper and more practical. Therefore, chemical plating has also become one of the important surface treatment methods for metal corrosion protection.

[0004] At present, the surface protection of copper-nickel alloy has changed from the chemical nickel-phosphorus plating process in the 1960s to the 1980s to the development of diversified chemical nickel plating, composite plating, multi-layer chemical layer, etc., and self-sacrificial plating has also become one of the main anti-corrosion measures. However, traditional self-sacrificial plating such as zinc plating and nickel plating has problems such as short protection life, great environmental impact on protection performance, not very ideal wear resistance of the plating, and manufacturing cost. In particular, if the electrochemical activity difference between the plating and the base metal is large, it may cause galvanic corrosion near the contact point, causing accelerated corrosion of the plating. Summary of the invention

[0005] In order to solve the above technical problems, the present invention proposes a self-sacrificial nanoparticle enhanced chemical deposition process for inhibiting pitting corrosion of B30 copper-nickel alloy, which adopts a self-sacrificial electrochemical corrosion protection strategy to effectively inhibit the pitting corrosion of copper-nickel alloy pipes.

[0006] To achieve the above object, the present invention provides a self-sacrificial nanoparticle enhanced chemical deposition process for inhibiting pitting corrosion of B30 copper-nickel alloy, comprising the following steps:

[0007] After alkaline and acid washing, the B30 copper-nickel alloy pipe is subjected to ultrasonic-assisted chemical nickel plating, and a nanoparticle-reinforced composite coating is plated on the inner wall of the B30 copper-nickel alloy pipe to achieve self-sacrificial nanoparticle reinforcement for pitting corrosion inhibition of the B30 copper-nickel alloy;

[0008] The chemical plating solution used in the ultrasonic-assisted chemical nickel plating process is an acidic chemical nickel plating solution, which contains a metal salt, a reducing agent, sodium acetate, ammonium citrate, nanoparticles and a stabilizer. The nanoparticles are a mixture of two or more of nano Y2O3 (yttrium oxide), nano La2O3 (lanthanum oxide), nano Gd2O3 (gadolinium oxide) and nano Nd2O3 (neodymium oxide).

[0009] The metal salt is used to alloy and regulate the intrinsic toughness of the coating to prevent cracking of the coating. The reducing agent is used to reduce H embrittlement (hydrogen embrittlement) and at the same time reduce the plating temperature by the temperature of the water bath. The addition of nanoparticles is used to reduce the overall corrosion current of the film layer and enhance wear resistance.

[0010] Furthermore, the acidic chemical nickel plating solution contains a metal salt with a concentration of 35 to 40 g / L, a reducing agent with a concentration of 10 to 20 g / L, sodium acetate with a concentration of 10 to 30 g / L, ammonium citrate with a concentration of 10 to 30 g / L, nanoparticles with a concentration of 2 to 3 g / L, and a stabilizer with a concentration of 0.5 to 5 g / L.

[0011] Furthermore, the metal salt is one or more of NiSO4 (nickel sulfate), CuSO4 (copper sulfate) and ZnSO4 (zinc sulfate), the reducing agent is one or more of NaH2PO2 (sodium hypophosphite), DMAB (dimethylaminoborane) and NaBH4 (sodium borohydride), and the stabilizer is thiourea.

[0012] Furthermore, the pH value of the acidic chemical nickel plating solution is adjusted to 4-6 with acetic acid.

[0013] Furthermore, the ultrasonic-assisted chemical nickel plating is specifically as follows: under ultrasonic-assisted conditions, the B30 copper-nickel alloy tube is immersed in deionized water, and an acidic chemical nickel plating solution flows in the tube, so as to plate a uniform nanoparticle-reinforced composite coating on the inner wall of the tube.

[0014] Furthermore, the flow rate of the acidic chemical nickel plating solution in the tube is 0.1-0.5 m / s, the temperature of the deionized water is 70-85° C., the ultrasonic frequency is 30-40 kHz, and the plating time is 60-90 min.

[0015] The role of ultrasound is to ensure the dispersion of the acidic chemical nickel plating solution without affecting the deposition of metal ions.

[0016] Furthermore, the alkaline solution for alkali washing comprises NaOH with a concentration of 100 to 120 g / L and a surfactant with a concentration of 0.1 to 0.5 g / L.

[0017] Furthermore, the purpose of the alkaline washing is to remove oil, grease and dirt on the inner surface of the pipe, specifically, the pipe is immersed in an alkaline solution at a temperature of 60 to 80°C for 8 to 10 minutes, and ultrasonic cleaning is assisted at a frequency of 20 to 30 kHz and a duration of 8 to 10 minutes.

[0018] High concentration alkali and low frequency ultrasound are mainly used to better remove dirt from the inner wall of the pipe.

[0019] Furthermore, the pickling acid solution contains phosphoric acid with a concentration of 12 to 25 g / L and nitric acid with a concentration of 20 to 40 mL / L.

[0020] Furthermore, the acid solution for pickling also includes a pickling slow-release agent, a complexing agent and a brightener.

[0021] Furthermore, the pickling is to use an acidic solution to circulate and flush the inner wall of the pipe at a high speed, the flow rate of the pickling solution in the pipe is 4 to 6 m / s, and the flushing time is 1 to 2 minutes.

[0022] The purpose of flushing with high-flow acidic solution is to quickly clean the inner surface of the pipe and reduce damage to the substrate.

[0023] The present invention also provides a self-sacrificial nanoparticle reinforced B30 copper-nickel alloy prepared by the chemical deposition process.

[0024] Compared with the prior art, the present invention has the following advantages and technical effects:

[0025] (1) The present invention uses an acidic chemical plating solution to obtain a chemical plating layer with good wear resistance, and increases the potential of the plating layer by adding nanoparticles, while keeping the potential of the plating layer slightly lower than the potential of the B30 copper-nickel alloy substrate, thereby reducing the corrosion current, playing a protective role of the sacrificial anode, effectively extending the protection period of the self-sacrificial plating layer, and improving the corrosion resistance of the plating layer; the addition of an ultrasonic process in ultrasonic-assisted chemical nickel plating makes the plating solution evenly dispersed and obtains a denser plating layer. The nanoparticle-enhanced chemical deposition process provided by the present invention significantly reduces the consumption rate of the plating layer and greatly improves the wear resistance, which is of great significance for inhibiting pitting corrosion of B30 copper-nickel alloy pipelines.

[0026] (2) The present invention utilizes the low stress of low hydrogen chemical plating to solve the problem of the bonding force between the coating and the B30 copper-nickel alloy substrate, and utilizes the addition of nanoparticles and the use of ultrasonic technology to improve the density and wear resistance of the coating. The process is cleverly designed, easy to operate, and easy to implement on pipe workpieces, ensuring that the consumption rate of the coating is significantly reduced on the basis of achieving the self-sacrificial protection effect, while giving the coating excellent wear resistance. Through this technology, not only the anti-corrosion performance of the pipe is optimized, but also its long-term reliability and economy are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0028] Figure 1 This is a SEM image of the nanoparticle-reinforced coating in the self-sacrificial nanoparticle-reinforced B30 copper-nickel alloy prepared in Example 1;

[0029] Figure 2 This is a SEM image of the self-sacrificial nickel-phosphorus-zinc layer in the common self-sacrificial nickel-phosphorus-zinc layer B30 copper-nickel alloy tube prepared in Comparative Example 10;

[0030] Figure 3 The figure is a comparison of TAF curves of Example 1(a) reinforced with nanoparticles and Comparative Example 1(b) without nanoparticles. DETAILED DESCRIPTION

[0031] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0032] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0033] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0034] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0035] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0036] The embodiment of the present invention provides a self-sacrificial nanoparticle enhanced chemical deposition process for inhibiting pitting corrosion of B30 copper-nickel alloy, comprising the following steps:

[0037] After alkaline and acid washing, the B30 copper-nickel alloy pipe is subjected to ultrasonic-assisted chemical nickel plating, and a nanoparticle-reinforced composite coating is plated on the inner wall of the B30 copper-nickel alloy pipe to achieve self-sacrificial nanoparticle reinforcement for pitting corrosion inhibition of the B30 copper-nickel alloy;

[0038] The chemical plating solution used in the ultrasonic-assisted chemical nickel plating process is an acidic chemical nickel plating solution, which contains a metal salt, a reducing agent, sodium acetate, ammonium citrate, nanoparticles and a stabilizer. The nanoparticles are a mixture of two or more of nano Y2O3, nano La2O3, nano Gd2O3 and nano Nd2O3.

[0039] In a preferred embodiment of the present invention, the acidic chemical nickel plating solution contains a metal salt with a concentration of 35 to 40 g / L, a reducing agent with a concentration of 10 to 20 g / L, sodium acetate with a concentration of 10 to 30 g / L, ammonium citrate with a concentration of 10 to 30 g / L, nanoparticles with a concentration of 2 to 3 g / L, and a stabilizer with a concentration of 0.5 to 5 g / L.

[0040] In a preferred embodiment of the present invention, the metal salt is one or more of NiSO4, CuSO4 and ZnSO4, the reducing agent is one or more of NaH2PO2, DMAB and NaBH4, and the stabilizer is thiourea.

[0041] In a preferred embodiment of the present invention, the acidic chemical nickel plating solution is adjusted to 4-6 with acetic acid.

[0042] In a preferred embodiment of the present invention, the ultrasonic assisted chemical nickel plating is specifically as follows: under ultrasonic assisted conditions, the B30 copper-nickel alloy pipe is immersed in deionized water, an acidic chemical nickel plating solution flows in the pipe, and a uniform nanoparticle reinforced composite coating is plated on the inner wall of the pipe.

[0043] In a preferred embodiment of the present invention, the flow rate of the acidic chemical nickel plating solution in the tube is 0.1-0.5 m / s, the deionized water immersion temperature is 70-85° C., the ultrasonic frequency is 30-40 kHz, and the plating time is 60-90 min.

[0044] In a preferred embodiment of the present invention, the alkaline solution for alkali washing comprises NaOH with a concentration of 100 to 120 g / L and a surfactant with a concentration of 0.1 to 0.5 g / L; preferably, the surfactant is an OP-emulsifier.

[0045] In a preferred embodiment of the present invention, the purpose of the alkaline washing is to remove oil, grease and dirt on the inner surface of the pipe, specifically, the pipe is immersed in an alkaline solution at a temperature of 60 to 80°C for 8 to 10 minutes, and ultrasonic cleaning is performed at a frequency of 20 to 30 kHz and a duration of 8 to 10 minutes.

[0046] In a preferred embodiment of the present invention, the pickling acid solution contains phosphoric acid with a concentration of 12 to 25 g / L and nitric acid with a concentration of 20 to 40 mL / L.

[0047] In a preferred embodiment of the present invention, the acidic solution for pickling may further include a pickling slow-release agent, a complexing agent and a brightener. In the embodiment of the present invention, the pickling slow-release agent used is specifically Lan-826, the complexing agent used is specifically sodium tripolyphosphate, sodium pyrophosphate, and sodium hexametaphosphate, and the brightener used can be purchased from the market without any requirements.

[0048] In a preferred embodiment of the present invention, the pickling is to use an acidic solution to circulate and flush the inner wall of the pipe at a high speed, the flow rate of the pickling solution in the pipe is 4 to 6 m / s, and the flushing time is 1 to 2 min.

[0049] The present invention also provides a self-sacrificial nanoparticle reinforced B30 copper-nickel alloy prepared by the chemical deposition process.

[0050] All raw materials used in the examples of the present invention are commercially available.

[0051] The technical solution of the present invention is further illustrated by the following embodiments.

[0052] Example 1

[0053] (1) Alkaline washing

[0054] Prepare an alkaline cleaning solution, which contains: 120 g / L NaOH and 0.1 g / L OP-emulsifier (surfactant); soak the B30 copper-nickel alloy pipe in the alkaline cleaning solution at a temperature of 70°C, and perform 20kHz ultrasonic cleaning for 10 minutes to remove dirt on the inner wall of the pipe;

[0055] (2) Pickling

[0056] Prepare a pickling solution, the pickling solution contains: 15 g / L phosphoric acid and 40 g / L nitric acid; heat deionized water to 60° C., place the pipe after alkali washing in step (1) therein, and flush the inside of the pipe with the pickling solution through a rubber ring at a high speed, the pickling solution flow rate is 4 m / s, and the flushing time is 2 min;

[0057] (3) Preparation of acidic chemical nickel plating solution

[0058] Sodium acetate, ammonium citrate and thiourea are dissolved in water and mixed uniformly to obtain a mixed solution, nickel sulfate, copper sulfate and zinc sulfate are weighed and mixed at a molar ratio of 5:2:1, respectively, and water is added to dissolve them, and then slowly poured into the mixed solution under stirring, and deionized water is added to 1 L to obtain a mixed solution (a);

[0059] The mixed solution (a) is stirred evenly and heated to 70° C., dimethylaminoborane and sodium hypophosphite are mixed at a molar ratio of 1:3, water is added to dissolve, and then the mixture is slowly poured into the mixed solution (a) under stirring to obtain a mixed solution (b), wherein the mixed solution (b) comprises: 35 g / L of metal salts (nickel sulfate, copper sulfate and zinc sulfate), 3 g / L of dimethylaminoborane, 13.5 g / L of sodium hypophosphite, 20 g / L of sodium acetate, 15 g / L of ammonium citrate, 1 g / L of thiourea, and 30 mL of lactic acid, wherein the lactic acid acts as a complexing agent to stabilize the pH value of the plating solution;

[0060] 1 g of nano-yttrium oxide and 1 g of nano-gadolinium oxide were mixed and added to the mixed solution (b) to obtain a mixed solution (c), and the mixed solution (c) was placed in a magnetic stirrer, the speed was set to 40 r / min, and the processing time was 5 min to obtain a uniformly dispersed nano-composite chemical nickel plating solution (nanoparticle concentration was 2 g / L); the pH value of the solution was adjusted to 4.5 with acetic acid to obtain an acidic chemical nickel plating solution, and the plating solution temperature was always maintained at 70° C.;

[0061] (4) Ultrasonic assisted chemical nickel plating

[0062] The B30 copper-nickel alloy pipe that has been alkali washed, acid washed and dried is placed in deionized water at a temperature of 70°C, and the acidic chemical nickel plating solution is slowly flowed into the inner wall of the pipe through a rubber tube at a flow rate of 0.3 m / s, and an ultrasonic frequency of 30 kHz is applied for plating for 1.5 hours. After the plating is completed, the pipe is taken out, rinsed with deionized water and dried to obtain a self-sacrificial nanoparticle reinforced B30 copper-nickel alloy pipe.

[0063] The SEM image of the nanoparticle-reinforced coating in the self-sacrificial nanoparticle-reinforced B30 copper-nickel alloy tube prepared in Example 1 is shown in FIG. Figure 1 .

[0064] Comparative Example 1

[0065] The same as Example 1, except that the acidic chemical nickel plating solution does not contain nanoparticles. The specific preparation method is as follows:

[0066] Sodium acetate, ammonium citrate and thiourea are dissolved in water and mixed uniformly to obtain a mixed solution, nickel sulfate, copper sulfate and zinc sulfate are weighed and mixed at a molar ratio of 5:2:1, respectively, and water is added to dissolve them, and then slowly poured into the mixed solution under stirring, and deionized water is added to 1 L to obtain a mixed solution (a);

[0067] The mixed solution (a) is stirred evenly and heated to 70° C., dimethylaminoborane and sodium hypophosphite are mixed at a molar ratio of 1:3, water is added to dissolve, and then the mixture is slowly poured into the mixed solution (a) under stirring to obtain a mixed solution (b), wherein the mixed solution (b) comprises: 35 g / L of metal salts (nickel sulfate, copper sulfate and zinc sulfate), 3 g / L of dimethylaminoborane, 13.5 g / L of sodium hypophosphite, 20 g / L of sodium acetate, 15 g / L of ammonium citrate, 1 g / L of thiourea, and 30 mL of lactic acid;

[0068] The pH value of the mixed solution (b) was adjusted to 4.5 with acetic acid to obtain an acidic chemical nickel plating solution, and the plating solution temperature was always maintained at 70°C.

[0069] The remaining steps are the same as in Example 1.

[0070] Through XRD and SEM tests, it can be known that the average grain size of the nano-composite coating of Example 1 is 40nm, which is one order of magnitude finer than the grain size of the general coating. Through electrochemical testing, the corrosion potential of the coating without nanoparticles (Comparative Example 1) is -0.74V, while the corrosion potential of the original B30 copper-nickel alloy pipe is -0.2V. The coating plays a protective role as a sacrificial anode, but it is consumed too quickly and the protection period is short. The corrosion potential of the composite coating with added nanoparticles (Example 1) is increased to -0.31V, which effectively extends the protection period of the coating while playing a self-sacrificial protection.

[0071] Wear resistance tests were carried out under the conditions of a sliding speed of 12 cm / s, a sliding distance of 200 m, and a pressure of 10 N. The results showed that the mass loss of the nano-composite coating of Example 1 was 0.16%, which effectively improved the wear resistance of the coating. In the static water immersion experiment, the nano-composite coating of Example 1 showed good protective performance. The coating was consumed after 6 months, exposing an uncorroded silver-gray matrix, which proved that the addition of nanoparticles and the use of ultrasonic technology effectively improved the life of the coating and played a corrosion protection effect.

[0072] The TAF curve comparison diagram of the coating of Example 1 and Comparative Example 1 is shown in Figure 3 , wherein (a) is Example 1, (b) is Comparative Example 1, Figure 3 It can be seen that after electrochemical testing, the corrosion potential of the basic coating (Comparative Example 1) is -0.83V, while the potential of the nanoparticle enhanced composite coating is -0.25V. While the nanoparticle enhanced composite coating plays the protective role of a sacrificial anode, its corrosion tendency is lower than that of the basic coating, and its corrosion current is increased by an order of magnitude compared to the basic coating, which can prove that its protection life is extended.

[0073] Example 2

[0074] (1) Alkaline washing

[0075] Prepare an alkaline cleaning solution, wherein the solution contains: NaOH 100g / L, OP-emulsifier 0.5g / L; soak the B30 copper-nickel alloy pipe in the alkaline cleaning solution at a temperature of 75°C, and perform 25kHz ultrasonic cleaning for 10 minutes to peel off the dirt on the inner wall of the pipe;

[0076] (2) Pickling

[0077] Prepare an acid pickling solution, wherein the solution contains: 25 g / L phosphoric acid and 35 g / L nitric acid; heat deionized water to 60° C., place the pipe after alkali cleaning in step (1) into the water, and flush the inside of the pipe with the acid pickling solution through a rubber ring at a high speed, with a flow rate of 6 m / s and a flushing time of 1 min;

[0078] (3) Preparation of acidic chemical nickel plating solution

[0079] Sodium acetate, ammonium citrate and thiourea are dissolved in water and mixed to obtain a mixed solution, nickel sulfate, copper sulfate and zinc sulfate are weighed and mixed at a molar ratio of 7:3:1, respectively, and water is added to dissolve them, and then slowly poured into the mixed solution under stirring, and deionized water is added to 1 L to obtain a mixed solution (a);

[0080] The mixed solution (a) is stirred evenly and heated to 75° C., dimethylaminoborane and sodium borohydride are mixed at a molar ratio of 2:3, water is added to dissolve, and then the mixture is slowly poured into the mixed solution (a) under stirring to obtain a mixed solution (b), wherein the mixed solution (b) comprises: 38 g / L of metal salts (nickel sulfate, copper sulfate and zinc sulfate), 5 g / L of dimethylaminoborane, 11.5 g / L of sodium borohydride, 25 g / L of sodium acetate, 20 g / L of ammonium citrate, 2 g / L of thiourea, and 30 mL of lactic acid;

[0081] 1 g of nano-yttrium oxide and 1 g of nano-gadolinium oxide were mixed and added to the mixed solution (b) to obtain a mixed solution (c), and the mixed solution (c) was placed in a magnetic stirrer, the speed was set to 40 r / min, and the processing time was 5 min to obtain a uniformly dispersed nano-composite chemical nickel plating solution (nanoparticle concentration was 2 g / L); the pH value of the solution was adjusted to 5 with acetic acid to obtain an acidic chemical nickel plating solution, and the plating solution temperature was always maintained at 75° C.;

[0082] (4) Ultrasonic assisted chemical nickel plating

[0083] The B30 copper-nickel alloy pipe that has been acid-washed, alkali-washed and dried is placed in deionized water at a temperature of 75°C, and the acidic chemical nickel plating solution is slowly circulated through the inner wall of the pipe through a rubber tube at a flow rate of 0.2 m / s, and an ultrasonic frequency of 35 kHz is applied for plating for 1.5 hours. After the plating is completed, the pipe is taken out, rinsed with deionized water and dried to obtain a self-sacrificial nanoparticle reinforced B30 copper-nickel alloy.

[0084] Comparative Example 2

[0085] The same as Example 2, except that the acidic chemical nickel plating solution does not contain nanoparticles. The specific preparation method is as follows:

[0086] Sodium acetate, ammonium citrate and thiourea are dissolved in water and mixed to obtain a mixed solution, nickel sulfate, copper sulfate and zinc sulfate are weighed and mixed at a molar ratio of 7:3:1, respectively, and water is added to dissolve them, and then slowly poured into the mixed solution under stirring, and deionized water is added to 1 L to obtain a mixed solution (a);

[0087] The mixed solution (a) is stirred evenly and heated to 75° C., dimethylaminoborane and sodium borohydride are mixed at a molar ratio of 2:3, water is added to dissolve, and then the mixture is slowly poured into the mixed solution (a) under stirring to obtain a mixed solution (b), wherein the mixed solution (b) comprises: 38 g / L of metal salts (nickel sulfate, copper sulfate and zinc sulfate), 5 g / L of dimethylaminoborane, 11.5 g / L of sodium borohydride, 25 g / L of sodium acetate, 20 g / L of ammonium citrate, 2 g / L of thiourea, and 30 mL of lactic acid;

[0088] The pH value of the mixed solution (b) was adjusted to 5 with acetic acid to obtain an acidic chemical nickel plating solution, and the plating solution temperature was always maintained at 75°C.

[0089] The remaining steps are the same as in Example 2.

[0090] Comparative Example 3

[0091] The same as Example 2, except that the ultrasonic process is not used, and step (4) is as follows:

[0092] The B30 copper-nickel alloy pipe that has been acid-washed, alkali-washed and dried is placed in deionized water at a temperature of 75°C, and the acidic chemical nickel plating solution is slowly circulated through the inner wall of the pipe through a rubber tube at a flow rate of 0.2 m / s. The plating is performed for 1.5 hours. After the plating is completed, the pipe is taken out, rinsed with deionized water and dried to obtain a nanoparticle-reinforced B30 copper-nickel alloy.

[0093] Through XRD and SEM tests, it can be known that the average grain size of the nano-composite coating of Example 2 is 47nm, which is one order of magnitude finer than the grain size of the general coating; the wear resistance of the coating of Example 2 of the present invention is effectively improved. At the same time, through electrochemical testing, the corrosion current of the nano-composite coating of Example 2 is lower than that of the coating without the assistance of nanoparticles (Comparative Example 2) and the coating without the application of ultrasonic process (Comparative Example 3), which theoretically proves that the addition of nanoparticles and the assistance of ultrasonic process effectively extend the protection period of the coating; the static water immersion experiment shows that the nano-composite coating of Example 2 shows good protective performance. The coating is consumed after 173 days, exposing the silver-gray matrix, which actually proves that the addition of nanoparticles and the use of ultrasonic process effectively improve the life of the coating, and at the same time have the effect of corrosion protection.

[0094] Example 3

[0095] (1) Alkaline washing

[0096] Prepare an alkaline cleaning solution, wherein the solution contains: NaOH 110g / L, OP-emulsifier 0.3g / L; soak the B30 copper-nickel alloy pipe in the alkaline cleaning solution at a temperature of 80°C, and perform 20kHz ultrasonic cleaning for 10 minutes to remove dirt on the inner wall of the pipe;

[0097] (2) Pickling

[0098] Prepare an acid pickling solution, wherein the solution contains: 25 g / L phosphoric acid and 40 g / L nitric acid; heat deionized water to 60° C., place the pipe after alkali cleaning in step (1) into the water, and flush the inside of the pipe with the acid pickling solution through a rubber ring at a high speed, with a flow rate of 6 m / s and a flushing time of 1 min;

[0099] (3) Preparation of acidic chemical nickel plating solution

[0100] Sodium acetate, ammonium citrate and thiourea are dissolved in water and mixed to obtain a mixed solution, nickel sulfate, copper sulfate and zinc sulfate are weighed and mixed at a molar ratio of 6:1:1, respectively, and water is added to dissolve them, and then slowly poured into the mixed solution under stirring, and deionized water is added to 1 L to obtain a mixed solution (a);

[0101] The mixed solution (a) is stirred evenly and heated to 80° C., sodium borohydride and sodium hypophosphite are mixed at a molar ratio of 4:5, water is added to dissolve, and then the mixture is slowly poured into the mixed solution (a) under stirring to obtain a mixed solution (b), wherein the mixed solution (b) comprises: 35 g / L of metal salts (nickel sulfate, copper sulfate and zinc sulfate), 6 g / L of sodium borohydride, 11.5 g / L of sodium hypophosphite, 20 g / L of sodium acetate, 15 g / L of ammonium citrate, 1.5 g / L of thiourea, and 30 mL of lactic acid;

[0102] 1 g of each of nano-yttrium oxide, nano-lanthanum oxide and nano-gadolinium oxide were mixed and added to the mixed solution (b) to obtain a mixed solution (c), and the mixed solution (c) was placed in a magnetic stirrer, the speed was set to 50 r / min, and the processing time was 5 min to obtain a uniformly dispersed nano-composite chemical nickel plating solution (nanoparticle concentration was 3 g / L); the pH value of the solution was adjusted to 4.7 with acetic acid to obtain an acidic chemical nickel plating solution, and the plating solution temperature was always maintained at 70° C.;

[0103] (4) Ultrasonic assisted chemical nickel plating

[0104] The B30 copper-nickel alloy pipe that has been acid-washed, alkali-washed and dried is placed in deionized water at a temperature of 70°C, and the acidic chemical nickel plating solution is slowly circulated through the inner wall of the pipe through a rubber tube at a flow rate of 0.1 m / s, and an ultrasonic frequency of 40 kHz is applied for plating for 1.5 hours. After the plating is completed, the pipe is taken out, rinsed with deionized water and dried to obtain a self-sacrificial nanoparticle reinforced B30 copper-nickel alloy.

[0105] Comparative Example 4

[0106] The same as Example 3, except that the acidic chemical nickel plating solution does not contain nanoparticles. The specific preparation method is as follows:

[0107] Sodium acetate, ammonium citrate and thiourea are dissolved in water and mixed to obtain a mixed solution, nickel sulfate, copper sulfate and zinc sulfate are weighed and mixed at a molar ratio of 6:1:1, respectively, and water is added to dissolve them, and then slowly poured into the mixed solution under stirring, and deionized water is added to 1 L to obtain a mixed solution (a);

[0108] The mixed solution (a) is stirred evenly and heated to 80° C., sodium borohydride and sodium hypophosphite are mixed at a molar ratio of 4:5, water is added to dissolve, and then the mixture is slowly poured into the mixed solution (a) under stirring to obtain a mixed solution (b), wherein the mixed solution (b) comprises: 35 g / L of metal salts (nickel sulfate, copper sulfate and zinc sulfate), 6 g / L of sodium borohydride, 11.5 g / L of sodium hypophosphite, 20 g / L of sodium acetate, 15 g / L of ammonium citrate, 1.5 g / L of thiourea, and 30 mL of lactic acid;

[0109] The pH value of the mixed solution (b) was adjusted to 4.7 with acetic acid to obtain an acidic chemical nickel plating solution, and the plating solution temperature was always maintained at 70°C.

[0110] The remaining steps are the same as in Example 3.

[0111] Comparative Example 5

[0112] The same as Example 3, except that the ultrasonic process is not used, and step (4) is as follows:

[0113] The B30 copper-nickel alloy pipe that has been acid-washed, alkali-washed and dried is placed in deionized water at a temperature of 70°C, and the acidic chemical nickel plating solution is slowly circulated through the inner wall of the pipe through a rubber tube at a flow rate of 0.1 m / s. The plating is performed for 1.5 hours. After the plating is completed, the pipe is taken out, rinsed with deionized water and dried to obtain a nanoparticle-reinforced B30 copper-nickel alloy.

[0114] Through XRD and SEM tests, it can be learned that the average grain size of the nano-composite coating of Example 3 is 60nm, which is one order of magnitude finer than the grain size of the general coating, but slightly coarser than the double nanoparticle system (Examples 1 and 2); the wear resistance of the coating of Example 3 of the present invention is effectively improved. At the same time, through electrochemical testing, the corrosion current of the nano-composite coating is lower than that of the coating without the assistance of nanoparticles (Comparative Example 4) and the coating without the ultrasonic process (Comparative Example 5), which theoretically proves that the addition of nanoparticles and the assistance of ultrasonic process effectively extend the protection period of the coating; in the static water immersion experiment, the nano-composite coating of Example 3 shows good protection performance. The coating is consumed after 194 days, exposing the silver-gray matrix, which actually proves that the addition of nanoparticles and the use of ultrasonic process effectively improve the life of the coating, and at the same time play a corrosion protection effect.

[0115] Example 4

[0116] (1) Alkaline washing

[0117] Prepare an alkaline cleaning solution, wherein the solution contains: NaOH 120g / L, OP-emulsifier 0.5g / L; immerse the B30 copper-nickel alloy pipe in the alkaline cleaning solution at a temperature of 85°C, and perform 20kHz ultrasonic cleaning for 8 minutes to remove dirt on the inner wall of the pipe;

[0118] (2) Pickling

[0119] Prepare an acid pickling solution, wherein the solution contains: 30 g / L phosphoric acid and 40 g / L nitric acid; heat deionized water to 60° C., place the pipe after alkali cleaning in step (1) into the water, and flush the inside of the pipe with the acid pickling solution through a rubber ring at a high speed, with a flow rate of 8 m / s and a flushing time of 1 min;

[0120] (3) Preparation of acidic chemical nickel plating solution

[0121] Sodium acetate, ammonium citrate and thiourea are dissolved in water and mixed to obtain a mixed solution, nickel sulfate, copper sulfate and zinc sulfate are weighed and mixed at a molar ratio of 7:3:2, respectively, and water is added to dissolve them, and then slowly poured into the mixed solution under stirring, and deionized water is added to 1 L to obtain a mixed solution (a);

[0122] The mixed solution (a) is stirred evenly and heated to 85° C., dimethylaminoborane and sodium hypophosphite are mixed at a molar ratio of 1:1, water is added to dissolve, and then the mixture is slowly poured into the mixed solution (a) under stirring to obtain a mixed solution (b), wherein the mixed solution (b) comprises: 35 g / L of metal salts (nickel sulfate, copper sulfate and zinc sulfate), 6 g / L of dimethylaminoborane, 9 g / L of sodium hypophosphite, 25 g / L of sodium acetate, 25 g / L of ammonium citrate, 3 g / L of thiourea, and 30 mL of lactic acid;

[0123] 1 g of each of nano-yttrium oxide, nano-gadolinium oxide and nano-neodymium oxide are mixed and added to the mixed solution (b) to obtain a mixed solution (c), and the mixed solution (c) is placed in a magnetic stirrer, the speed is set to 50 r / min, and the processing time is 5 min to obtain a uniformly dispersed nano-composite chemical nickel plating solution (nanoparticle concentration is 3 g / L); the pH value of the solution is adjusted to 4.0 with acetic acid to obtain an acidic chemical nickel plating solution, and the plating solution temperature is always maintained at 85° C.;

[0124] (4) Ultrasonic assisted chemical nickel plating

[0125] The B30 copper-nickel alloy pipe that has been acid-washed, alkali-washed and dried is placed in deionized water at a temperature of 85°C, and the acidic chemical nickel plating solution is slowly circulated through the inner wall of the pipe through a rubber tube at a flow rate of 0.1 m / s, and an ultrasonic frequency of 40 kHz is applied for plating for 1.5 hours. After the plating is completed, the pipe is taken out, rinsed with deionized water and dried to obtain a self-sacrificial nanoparticle reinforced B30 copper-nickel alloy.

[0126] Comparative Example 6

[0127] The same as Example 4, except that the acidic chemical nickel plating solution does not contain nanoparticles. The specific preparation method is as follows:

[0128] Sodium acetate, ammonium citrate and thiourea are dissolved in water and mixed to obtain a mixed solution, nickel sulfate, copper sulfate and zinc sulfate are weighed and mixed at a molar ratio of 7:3:2, respectively, and water is added to dissolve them, and then slowly poured into the mixed solution under stirring, and deionized water is added to 1 L to obtain a mixed solution (a);

[0129] The mixed solution (a) is stirred evenly and heated to 85° C., dimethylaminoborane and sodium hypophosphite are mixed at a molar ratio of 1:1, water is added to dissolve, and then the mixture is slowly poured into the mixed solution (a) under stirring to obtain a mixed solution (b), wherein the mixed solution (b) comprises: 35 g / L of metal salts (nickel sulfate, copper sulfate and zinc sulfate), 6 g / L of dimethylaminoborane, 9 g / L of sodium hypophosphite, 25 g / L of sodium acetate, 25 g / L of ammonium citrate, 3 g / L of thiourea, and 30 mL of lactic acid;

[0130] The pH value of the mixed solution (b) was adjusted to 4.0 with acetic acid to obtain an acidic chemical nickel plating solution, and the plating solution temperature was always maintained at 85°C.

[0131] The remaining steps are the same as in Example 4.

[0132] Comparative Example 7

[0133] The same as Example 4, except that the ultrasonic process is not used, and step (4) is as follows:

[0134] The B30 copper-nickel alloy pipe that has been acid-washed, alkali-washed and dried is placed in deionized water at a temperature of 85°C, and the acidic chemical nickel plating solution is slowly circulated through the inner wall of the pipe through a rubber tube at a flow rate of 0.1 m / s. The plating is performed for 1.5 hours. After the plating is completed, the pipe is taken out, rinsed with deionized water and dried to obtain a nanoparticle-reinforced B30 copper-nickel alloy.

[0135] Through XRD and SEM tests, it can be known that the average grain size of the nano-composite coating of Example 4 is 67nm, which is one order of magnitude finer than the grain size of the general coating, but slightly coarser than the double nanoparticle system (Examples 1 and 2); the wear resistance of the coating of Example 4 of the present invention is effectively improved. At the same time, through electrochemical testing, the corrosion current of the nano-composite coating is lower than that of the coating without the assistance of nanoparticles (Comparative Example 6) and the coating without ultrasonic process (Comparative Example 7), which theoretically proves that the addition of nanoparticles and the assistance of ultrasonic process effectively extend the protection period of the coating; in the static water immersion experiment, the nano-composite coating of Example 4 shows good protection performance. The coating is consumed after 189 days, exposing the silver-gray matrix, which actually proves that the addition of nanoparticles and the use of ultrasonic process effectively improve the life of the coating, and at the same time play a corrosion protection effect.

[0136] Example 5

[0137] (1) Alkaline washing

[0138] Prepare an alkaline cleaning solution, wherein the solution contains: NaOH 115g / L, OP-emulsifier 0.3g / L; soak the B30 copper-nickel alloy pipe in the alkaline cleaning solution at a temperature of 70°C, and perform 25kHz ultrasonic cleaning for 10 minutes to remove dirt on the inner wall of the pipe;

[0139] (2) Pickling

[0140] Prepare an acid pickling solution, wherein the solution contains: 15 g / L phosphoric acid and 35 g / L nitric acid; heat deionized water to 70° C., place the pipe after alkali cleaning in step (1) into the water, and flush the inside of the pipe with the acid pickling solution through a rubber ring at a high speed, with a flow rate of 6 m / s and a flushing time of 2 min;

[0141] (3) Preparation of acidic chemical nickel plating solution

[0142] Sodium acetate, ammonium citrate and thiourea are dissolved in water and mixed uniformly to obtain a mixed solution, nickel sulfate, copper sulfate and zinc sulfate are weighed and mixed at a molar ratio of 9:4:2, respectively, and water is added to dissolve them, and then slowly poured into the mixed solution under stirring, and deionized water is added to 1 L to obtain a mixed solution (a);

[0143] The mixed solution (a) is stirred evenly and heated to 70° C., dimethylaminoborane and sodium hypophosphite are mixed at a molar ratio of 2:1, water is added to dissolve, and then the mixture is slowly poured into the mixed solution (a) under stirring to obtain a mixed solution (b), wherein the mixed solution (b) comprises: 35 g / L of metal salts (nickel sulfate, copper sulfate and zinc sulfate), 9 g / L of dimethylaminoborane, 6 g / L of sodium hypophosphite, 30 g / L of sodium acetate, 30 g / L of ammonium citrate, 5 g / L of thiourea, and 30 mL of lactic acid;

[0144] 1 g of each of nano-yttrium oxide, nano-gadolinium oxide and nano-neodymium oxide are mixed and added to the mixed solution (b) to obtain a mixed solution (c), and the mixed solution (c) is placed in a magnetic stirrer, the rotation speed is set to 50 r / min, and the processing time is 5 min to obtain a uniformly dispersed nano-composite chemical nickel plating solution (nanoparticle concentration is 3 g / L); the pH value of the solution is adjusted to 5.5 with acetic acid to obtain an acidic chemical nickel plating solution, and the plating solution temperature is always maintained at 80° C.;

[0145] (4) Ultrasonic assisted chemical nickel plating

[0146] The B30 copper-nickel alloy pipe that has been acid-washed, alkali-washed and dried is placed in deionized water at a temperature of 80°C, and the acidic chemical nickel plating solution is slowly circulated through the inner wall of the pipe through a rubber tube at a flow rate of 0.1 m / s, and an ultrasonic frequency of 40 kHz is applied for plating for 1.5 hours. After the plating is completed, the pipe is taken out, rinsed with deionized water and dried to obtain a self-sacrificial nanoparticle reinforced B30 copper-nickel alloy.

[0147] Comparative Example 8

[0148] The same as Example 5, except that the acidic chemical nickel plating solution does not contain nanoparticles. The specific preparation method is as follows:

[0149] Sodium acetate, ammonium citrate and thiourea are dissolved in water and mixed uniformly to obtain a mixed solution, nickel sulfate, copper sulfate and zinc sulfate are weighed and mixed at a molar ratio of 9:4:2, respectively, and water is added to dissolve them, and then slowly poured into the mixed solution under stirring, and deionized water is added to 1 L to obtain a mixed solution (a);

[0150] The mixed solution (a) is stirred evenly and heated to 70° C., dimethylaminoborane and sodium hypophosphite are mixed at a molar ratio of 2:1, water is added to dissolve, and then the mixture is slowly poured into the mixed solution (a) under stirring to obtain a mixed solution (b), wherein the mixed solution (b) comprises: 35 g / L of metal salts (nickel sulfate, copper sulfate and zinc sulfate), 9 g / L of dimethylaminoborane, 6 g / L of sodium hypophosphite, 30 g / L of sodium acetate, 30 g / L of ammonium citrate, 5 g / L of thiourea, and 30 mL of lactic acid;

[0151] The pH value of the mixed solution (b) was adjusted to 5.5 with acetic acid to obtain an acidic chemical nickel plating solution, and the plating solution temperature was always maintained at 80°C.

[0152] The remaining steps are the same as in Example 5.

[0153] Comparative Example 9

[0154] The same as Example 5, except that the ultrasonic process is not used, and step (4) is as follows:

[0155] The B30 copper-nickel alloy pipe that has been acid-washed, alkali-washed and dried is placed in deionized water at a temperature of 80°C, and the acidic chemical nickel plating solution is slowly circulated through the inner wall of the pipe through a rubber tube at a flow rate of 0.1 m / s. The plating is performed for 1.5 hours. After the plating is completed, the pipe is taken out, rinsed with deionized water and dried to obtain a nanoparticle-reinforced B30 copper-nickel alloy.

[0156] Through XRD and SEM tests, it can be known that the average grain size of the nano-composite coating of Example 5 is 64nm, which is one order of magnitude finer than the grain size of the general coating, but slightly coarser than the double nanoparticle system (Examples 1 and 2); the wear resistance of the coating of Example 5 of the present invention is effectively improved. At the same time, after electrochemical testing, the corrosion current of the nano-composite coating of Example 5 is lower than that of the coating without the assistance of nanoparticles (Comparative Example 8) and the coating without ultrasonic process (Comparative Example 9), which theoretically proves that the addition of nanoparticles and the assistance of ultrasonic process effectively extend the protection period of the coating; in the static water immersion experiment, the nano-composite coating of Example 5 shows good protection performance, and the coating is consumed after 191 days, exposing the silver-gray matrix, which actually proves that the addition of nanoparticles and the use of ultrasonic process effectively improve the life of the coating, and at the same time have the effect of corrosion protection.

[0157] Comparative Example 10

[0158] A common self-sacrificial anti-corrosion coating for metal pipes, the preparation method of which comprises the following steps:

[0159] (1) The same as Example 1, except that the B30 copper-nickel alloy pipe is not subjected to the auxiliary ultrasonic process and the pipe flushing cleaning process, and the pipe is directly cleaned after alkali washing, acid washing, water washing and drying for standby use;

[0160] (2) Dissolve citric acid, aminoacetic acid, nickel sulfate and zinc sulfate in water and stir to obtain a mixed solution, dissolve sodium hypophosphite in water, and then slowly pour it into the mixed solution while stirring, finally add lactic acid and stir to obtain a mixed solution (a). The mixed solution (a) contains: 27 g / L nickel sulfate, 8 g / L zinc sulfate, 25 g / L sodium hypophosphite, 15 g / L citric acid, 15 g / L aminoacetic acid, and 10 mL lactic acid; adjust the pH value of the solution to 7.5 with concentrated ammonia water, and heat the plating solution to 80°C;

[0161] (3) The B30 copper-nickel alloy tube pre-treated in step (1) is placed in the mixed solution (a) for plating for 1.5 hours, taken out, rinsed with deionized water, and dried to obtain a commonly used self-sacrificial nickel-phosphorus-zinc layer B30 copper-nickel alloy tube.

[0162] The SEM image of the self-sacrificial nickel-phosphorus-zinc layer in the common self-sacrificial nickel-phosphorus-zinc layer B30 copper-nickel alloy pipe prepared in comparative example 10 is shown in Figure 2 .

[0163] Through XRD and SEM tests, it can be known that the average grain of the self-sacrificial nickel-phosphorus-zinc layer of comparative example 10 is 200nm, the unit cell particles are large, and the density of the coating is low; when the sliding speed is 12cm / s, the sliding distance is 200m, and the wear test is carried out under the wear resistance test of 10N, the mass loss of the nickel-phosphorus-zinc coating is 0.59%, and the wear resistance and bonding strength are worse than those of Example 1. After electrochemical testing, the corrosion potential of the coating is -0.65V, and the substrate potential is -0.2V. The coating plays the protective role of a sacrificial anode, but the corrosion current is greater than that of the coating in Example 1. Theoretical analysis shows that the comparative coating is consumed too quickly and the protection period is short. In the static water immersion experiment, the comparative coating was completely consumed within 30 days, and the anti-corrosion performance was much lower than that of the nanoparticle enhanced coating in Example 1.

[0164] Comparative Example 11

[0165] A self-sacrificial anti-corrosion coating of a commonly used multi-primary salt reducing agent system, the preparation method of which comprises the following steps:

[0166] (1) The same as Example 1, except that the B30 copper-nickel alloy pipe is not subjected to the auxiliary ultrasonic process and the pipe flushing cleaning process, and the pipe is directly cleaned after alkali washing, acid washing, water washing and drying for standby use;

[0167] (2) Sodium acetate, ammonium citrate and thiourea are dissolved in water and mixed to obtain a mixed solution; nickel sulfate, copper sulfate and zinc sulfate are weighed and mixed at a molar ratio of 7:3:1, dissolved in water, and then slowly poured into the mixed solution under stirring; deionized water is added to 1L to obtain a mixed solution (a); the mixed solution (a) is stirred and heated to 85°C; dimethylaminoborane and sodium borohydride are mixed at a molar ratio of 2:1, dissolved in water, and then slowly poured into the mixed solution (a) under stirring to obtain a mixed solution (b); the mixed solution (b) contains: 35 g / L of metal salts (nickel sulfate, copper sulfate and zinc sulfate), 9 g / L of dimethylaminoborane, 6 g / L of sodium borohydride, 30 g / L of sodium acetate, 30 g / L of ammonium citrate, 5 g / L of thiourea, and 30 mL of lactic acid; the pH value of the solution is adjusted to 5.5 with concentrated ammonia water, and the plating solution temperature is heated to 85°C;

[0168] (3) Plating the B30 copper-nickel alloy pipe pre-treated in step (1) in the mixed solution (b) for 1.5 hours, taking it out, rinsing it with deionized water, and drying it to obtain a B30 copper-nickel alloy pipe with a self-sacrificial anti-corrosion coating of a multi-main salt reducing agent system.

[0169] Through XRD and SEM tests, it can be known that the average grain of the coating of Comparative Example 2 is 150nm, the unit cell particles are large, and the density of the coating is low; under the wear resistance test of 10N with a sliding speed of 12cm / s and a sliding distance of 200m, the mass loss of the nickel-phosphorus-zinc coating is 0.71%, and the wear resistance and bonding strength are worse than those of Example 1. After electrochemical testing, the corrosion potential of the coating is -0.51V, and the substrate potential is -0.2V. The coating plays the protective role of a sacrificial anode, but the corrosion current is greater than that of the coating in Example 1. Theoretical analysis shows that the comparative coating is consumed too quickly and the protection period is short. In the static water immersion experiment, the comparative coating was completely consumed within 90 days, and the anti-corrosion performance was much lower than that of the nanoparticle-enhanced coating in Example 1.

[0170] The above are only preferred specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A self-sacrificial nanoparticle enhanced chemical deposition process for pitting inhibition of B30 copper-nickel alloy, characterized in that: The following steps are involved: After alkaline and acid washing, the B30 copper-nickel alloy pipe is subjected to ultrasonic-assisted chemical nickel plating, and a nanoparticle-reinforced composite coating is plated on the inner wall of the B30 copper-nickel alloy pipe to achieve self-sacrificial nanoparticle reinforcement for pitting corrosion inhibition of the B30 copper-nickel alloy; The chemical plating solution used in the ultrasonic-assisted chemical nickel plating process is an acidic chemical nickel plating solution, which contains a metal salt, a reducing agent, sodium acetate, ammonium citrate, nanoparticles and a stabilizer. The nanoparticles are a mixture of two or more of nano-yttrium oxide, nano-lanthanum oxide, nano-gadolinium oxide and nano-neodymium oxide.

2. The self-sacrificial nanoparticle enhanced chemical deposition process for pitting inhibition of B30 copper-nickel alloy according to claim 1, characterized in that: The acidic chemical nickel plating solution contains a metal salt with a concentration of 35 to 40 g / L, a reducing agent with a concentration of 10 to 20 g / L, sodium acetate with a concentration of 10 to 30 g / L, ammonium citrate with a concentration of 10 to 30 g / L, nanoparticles with a concentration of 2 to 3 g / L, and a stabilizer with a concentration of 0.5 to 5 g / L.

3. The self-sacrificial nanoparticle enhanced chemical deposition process for pitting inhibition of B30 copper-nickel alloy according to claim 2, characterized in that: The metal salt is one or more of nickel sulfate, copper sulfate and zinc sulfate, the reducing agent is one or more of sodium hypophosphite, dimethylaminoborane and sodium borohydride, and the stabilizer is thiourea.

4. The self-sacrificial nanoparticle enhanced chemical deposition process for pitting inhibition of B30 copper-nickel alloy according to claim 2, characterized in that: The pH value of the acidic chemical nickel plating solution is adjusted to 4-6 with acetic acid.

5. The self-sacrificial nanoparticle enhanced chemical deposition process for pitting inhibition of B30 copper-nickel alloy according to claim 1, characterized in that: The ultrasonic-assisted chemical nickel plating is specifically as follows: under ultrasonic-assisted conditions, a B30 copper-nickel alloy tube is immersed in deionized water, and an acidic chemical nickel plating solution flows in the tube, so that a uniform nanoparticle-reinforced composite coating is plated on the inner wall of the tube.

6. The self-sacrificial nanoparticle enhanced chemical deposition process for pitting inhibition of B30 copper-nickel alloy according to claim 5, characterized in that: The flow rate of the acidic chemical nickel plating solution in the tube is 0.1-0.5 m / s, the temperature of the deionized water is 70-85° C., the ultrasonic frequency is 30-40 kHz, and the plating time is 60-90 min.

7. The self-sacrificial nanoparticle enhanced chemical deposition process for pitting inhibition of B30 copper-nickel alloy according to claim 1, characterized in that: The alkaline solution for alkali washing comprises NaOH with a concentration of 100 to 120 g / L and a surfactant with a concentration of 0.1 to 0.5 g / L.

8. The self-sacrificial nanoparticle enhanced chemical deposition process for pitting inhibition of B30 copper-nickel alloy according to claim 1, characterized in that: The pickling acid solution contains phosphoric acid with a concentration of 12 to 25 g / L and nitric acid with a concentration of 20 to 40 mL / L.

9. A self-sacrificial nanoparticle reinforced B30 copper-nickel alloy prepared by the chemical deposition process according to any one of claims 1 to 8.

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