Passivation solution as well as preparation method and application thereof

Abstract

The invention discloses a passivation solution as well as a preparation method and application thereof. The passivation solution is composed of the following components: 4.0-10.0% of a film-forming agent, 2.0-6.0% of an auxiliary film-forming agent, 1.0-10.0% of an oxidizing agent, 2.0-6.0% of boron powder, and the balance of deionized water. The effective components of the film-forming agent are a benzotriazole derivative and decamethylcyclopentasiloxane, the effective components of the auxiliary film-forming agent are sodium molybdate and sodium tungstate, and the effective component of the oxidizing agent is hydrogen peroxide. The method for passivating B30 cupronickel by using the passivation solution comprises the following steps: (1) carrying out surface pretreatment on a cupronickel sample to remove pollutants and an oxide layer on the surface of the cupronickel sample; (2) the pretreated cupronickel sample is put into a passivation solution, the passivation temperature ranges from 25 DEG C to 60 DEG C, the pH value ranges from 4 to 10, and the passivation treatment time ranges from 5 min to 60 min; and (3) the cupronickel sample treated in the step (2) is dried under the condition of 60-100 DEG C, and passivation is completed. The method has the characteristics that chromium-salt-free environment-friendly passivation of the B30 cupronickel is realized, and meanwhile, the corrosion-resistant effect of a passivation film in a long-term corrosion-resistant environment is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to a passivation solution and its preparation method and application, and belongs to the technical field of cupronickel surface treatment. BACKGROUND

[0002] Copper-nickel alloy has a long history of application in marine engineering. Its excellent corrosion resistance, ability to resist marine biofouling, and excellent cold workability make it an indispensable material in the field of marine engineering. With the development of technology, the research on the corrosion behavior and protection technology of copper-nickel alloy is also continuously deepened to improve its performance and service life in marine environment. Copper-nickel alloy can form a dense oxide film under scouring conditions, and has excellent resistance to seawater scouring corrosion. It is often used to manufacture seawater pipeline systems. However, the formation of a dense oxide film requires long-term scouring in clean low-speed seawater, which usually takes several months, greatly increasing the time cost. Direct use of the pipeline exposes the surface of the metal to high-speed seawater scouring, which can cause localized corrosion and reduce the reliability of the pipeline. Therefore, it is necessary to form a passivation film on the surface of copper-nickel alloy to replace the natural oxide film formed by immersion, and to play a transitional and protective role in the process of forming a dense oxide film under seawater scouring.

[0003] The passivation process in industrial production often uses chromic acid and chromate. Although its process is relatively simple and mature, and the passivation effect is excellent, the use of chromate in its aqueous solution contains hexavalent chromium, which is a strong carcinogen. Long-term contact and use can cause serious harm to the human body, and is extremely harmful to the environment, causing serious environmental pollution. In today's world, the promotion of environmental protection and green is advocated. The chromium-free passivation formula of copper and its alloy has great research value. SUMMARY

[0004] The purpose of the present application is to provide a passivation solution for cupronickel and its preparation method and application, aiming to solve the serious health hazards and environmental pollution problems caused by long-term contact and use of chromic acid and chromate in current industrial passivation processes.

[0005] To achieve the above-mentioned purpose, the following technical solutions are adopted in the present application:

[0006] The present application provides a passivation solution, which consists of the following components in mass percentage: 4.0-10.0% of film forming agent, 2.0-6.0% of auxiliary film forming agent, 1.0-10.0% of oxidizing agent, 2.0-6.0% of boron powder, and the rest is deionized water; the effective components of the film forming agent are benzotriazole derivatives and decamethylcyclopentasiloxane, the effective components of the auxiliary film forming agent are sodium molybdate and sodium tungstate, and the effective component of the oxidizing agent is hydrogen peroxide.

[0007] Preferably, the film-forming agent is a mixture of benzotriazole derivative, decamethylcyclopentasiloxane and deionized water, wherein the mass ratio of benzotriazole derivative and decamethylcyclopentasiloxane is 3-10:4-9.

[0008] Preferably, the mass ratio of sodium tungstate and sodium molybdate in the auxiliary film-forming agent is 1-2:1-2.

[0009] The application also provides a preparation method of the passivation solution, comprising the following steps:

[0010] (1) adding the formula amount of benzotriazole derivative and decamethylcyclopentasiloxane into deionized water, and stirring to form solution A;

[0011] (2) adding the formula amount of boron powder into solution A, heating the mixture to 50-60℃, stirring to dissolve the boron powder completely;

[0012] (3) mixing the formula amount of auxiliary film-forming agent and deionized water uniformly, then adding the uniform mixture and oxidizing agent into the solution after the boron powder is completely dissolved to form solution B, and stirring solution B at 50-60℃ to react fully to obtain the passivation solution.

[0013] The application also provides a passivation method for using the passivation solution for passivation of cupronickel, comprising the following steps:

[0014] (1) first, performing surface pretreatment on the cupronickel sample to remove contaminants and oxide layers on the surface of the cupronickel sample;

[0015] (2) placing the pretreated cupronickel sample into the passivation solution, and performing passivation at a temperature of 25-60℃ and a pH value of 4-10 for 5-60 min;

[0016] (3) drying the cupronickel sample treated in step (2) at a temperature of 60-100℃ to obtain a passivation film on the surface of the cupronickel sample, and completing the passivation.

[0017] Preferably, the step (2) requires complete immersion of the cupronickel sample during passivation and uses ultrasonic vibration stirring.

[0018] Preferably, the surface pretreatment comprises sanding and pickling.

[0019] Preferably, the pickling requires complete immersion of the cupronickel sample and constant swinging.

[0020] Preferably, the pickling uses a dilute sulfuric acid solution.

[0021] Preferably, in the dilute sulfuric acid solution, the mass ratio of sulfuric acid to water is 1-3:10-25.

[0022] Advantages of the present application:

[0023] 1. The passivation solution provided by the present application is composed of the following components in terms of mass percentage: 4.0-10.0% of film forming agent, 2.0-6.0% of auxiliary film forming agent, 1.0-10.0% of oxidizing agent, 2.0-6.0% of boron powder, and the rest of deionized water. The passivation solution replaces traditional chromate system passivation solution, chromium-free system passivation solution and traditional copper passivation solution, uses benzotriazole derivative and decamethylcyclopentasiloxane as the film forming agent, greatly improves the uniformity and compactness of the passivation film on the surface of cupronickel, thereby improving the high-temperature oxidation resistance and corrosion resistance of the surface of cupronickel, and is non-toxic and non-polluting. The passivation solution is easy to prepare, the passivation process is simple, and the passivation time is short, which is 5-60 minutes, and the effect is good. The speed requirement of the process generation process is met.

[0024] 2. The passivation solution provided by the present application is used for the passivation of cupronickel. The obtained passivation film layer structure is compact and uniform. Due to the addition of boron powder, the oxidation layer has excellent corrosion resistance and high-temperature oxidation resistance. In the artificial seawater immersion experiment, the corrosion rate is only 30% of the same series of passivation solutions on the market.

[0025] 3. The passivation solution provided by the present application is used for the passivation of cupronickel. The process flow is short, and multiple rinsing in the traditional passivation process is not required, thereby saving a large amount of water resources. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is the surface topography diagram of only surface treatment without passivation in Example 1 of the present application.

[0027] Figure 2 is the surface topography diagram of the passivation film after the treatment of B30 cupronickel sample in Example 1 of the present application. DETAILED DESCRIPTION

[0028] The principles and characteristics of the present application are described below in combination with the drawings. The examples are only used to explain the present application, and are not used to limit the scope of the present application. The specific conditions are not indicated in the examples, and are carried out according to the conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products that can be purchased on the market.

[0029] The present application provides a kind of passivation solution, which is composed of the following components according to the following mass percentage: 4.0-10.0% of film forming agent, 2.0-6.0% of auxiliary film forming agent, 1.0-10.0% of oxidizing agent, 2.0-6.0% of boron powder, and the rest of deionized water;The effective component of the film forming agent is benzotriazole derivative and decamethylcyclopentasiloxane, the effective component of auxiliary film forming agent is sodium molybdate and sodium tungstate, and the effective component of oxidizing agent is hydrogen peroxide.

[0030] Specifically, the Irgamet39 (benzotriazole derivative) and decamethylcyclopentasiloxane (D5) as film-forming agents, which react with the substrate to form a passivation film on the metal surface or form an adsorption film on the metal surface to achieve the corrosion inhibition effect; the sodium molybdate and sodium tungstate are auxiliary film-forming agents, which have a certain corrosion inhibition effect or complex effect with the film-forming agent to improve the passivation effect; the boron powder is attached to the inside of the oxide layer, and when the environment contains chloride ions, the dissolved boron can fix the chloride ions, thereby hindering the destruction of the passivation film. Hydrogen peroxide is an oxidizing agent, which mainly oxidizes copper to an ionic state to promote the passivation process. The above-mentioned several solvents jointly react with copper ions to form a dense and uniform passivation film, which has excellent corrosion resistance, high-temperature oxidation resistance and good conductivity. The passivation solution has the characteristics of non-toxicity, non-pollution and fewer types of additives.

[0031] The passivation mechanism of the passivation solution is as follows: first, the oxidation and dissolution of the copper substrate to generate CuO and Cu2O. Second, the film-forming agents of Irgamet39 (benzotriazole derivative) and decamethylcyclopentasiloxane (D5) react with copper ions to generate Cu polymer; at the same time, the acid ions in the auxiliary film-forming agents of sodium molybdate and sodium tungstate react with the remaining copper ions to generate compounds to improve the passivation effect; finally, the polymer film spontaneously reorganizes to reach the most stable state, and at the same time, CuO and Cu2O particles diffuse in the voids to form a dense passivation film.

[0032] Preferably, the film-forming agent is a mixed solution composed of benzotriazole derivative, decamethylcyclopentasiloxane and deionized water, and the mass ratio of benzotriazole derivative to decamethylcyclopentasiloxane is 3-10:4-9.

[0033] Preferably, the mass ratio of cerium nitrate to lanthanum nitrate is 1-2:1-2.

[0034] Specifically, the passivation film prepared in the above-mentioned optimized mass ratio range has excellent corrosion resistance and high-temperature oxidation resistance. When the content of the effective components of the above-mentioned passivation solution is lower than the above-mentioned content range, the reaction is incomplete and the oxidation film is incomplete. When the content of the effective components of the above-mentioned passivation solution is higher than the above-mentioned content range, the components of the solution itself will damage or corrode the oxidation film, resulting in uneven oxidation film. When the content of the effective components of the above-mentioned passivation solution is higher or lower than the above-mentioned content range, the passivation effect of copper and its alloy will be reduced, and the oxidation resistance and corrosion resistance will be affected. For example, when the content of decamethylcyclopentasiloxane is higher than the above-mentioned content range, the oxidation film will be uneven, the surface color of the sample will be uneven, and the oxidation resistance will decrease.

[0035] The preparation method of the passivation solution comprises the following steps:

[0036] (1) adding the formula amount of benzotriazole derivative and decamethylcyclopentasiloxane into deionized water, stirring to form solution A;

[0037] (2) adding the formula amount of boron powder into solution A, heating the mixture to a target temperature one, stirring to dissolve the boron powder completely; preferably, the target temperature one is 50-60℃;

[0038] (3) adding the formula amount of auxiliary film-forming agent and oxidizing agent into the solution after the boron powder is completely dissolved, forming solution B, stirring solution B at a target temperature two and allowing it to react completely to obtain the passivation solution.

[0039] Preferably, the target temperature two is 50-60℃, and solution B is stirred for 6-10 minutes at a frequency of 90Hz by ultrasonic vibration.

[0040] The passivation method for passivating B30 cupronickel using the passivation solution of the present application comprises the following steps:

[0041] (1) first, pre-treating the surface of the cupronickel sample to remove contaminants and oxide layers on the surface of the cupronickel sample;

[0042] (2) placing the pre-treated cupronickel sample into the passivation solution, with a passivation temperature of 25-60℃, a pH value of 4-10, and a passivation treatment time of 5-60 minutes;

[0043] (3) drying the cupronickel sample treated in step (2) at a temperature of 60-100℃ to obtain a passivation film on the surface of the cupronickel sample, completing the passivation.

[0044] Specifically, the cupronickel passivation film obtained by using the above passivation process has good quality, is uniform and dense, and has no surface defects such as cracks, bubbles and pores. If the values of the process parameters used are higher or lower than the above process parameter ranges, it will have a significant negative impact on the quality of the passivation film of the sample. For example, if the value of the passivation temperature exceeds the passivation temperature range of the above process, it will be difficult to adsorb and form a film, and if the value of the pH used exceeds or is lower than the pH range of the above solution, bubbles will appear on the surface of the passivation film.

[0045] The passivation treatment method of the present application has a short process flow and does not need to perform multiple rinsing in the traditional passivation process, thereby saving a large amount of water resources.

[0046] Preferably, step (2) requires complete immersion of the cupronickel sample during passivation and uses ultrasonic vibration stirring.

[0047] Specifically, complete immersion ensures sufficient acidification of the cupronickel sample, and ultrasonic vibration stirring improves the acidification efficiency.

[0048] Preferably, the surface pre-treatment includes sanding and pickling.

[0049] Preferably, the pickling requires the cupronickel sample to be fully immersed and constantly shaken.

[0050] Specifically, the surface of the sample needs to be pre-treated by pickling and sanding before passivation, a fully immersed passivation method is used, a heating furnace, a stirring rod and ultrasonic stirring are used to ensure that the reaction is fully carried out. The passivation solution forms a uniform and dense passivation film on the surface of the cupronickel sample, which plays an anti-oxidation and corrosion resistance role.

[0051] Preferably, the pickling uses a dilute sulfuric acid solution.

[0052] Specifically, dilute sulfuric acid pickling can effectively remove the oxide layer and rust on the surface of the metal, restore the metal surface to its original state, and ensure the quality and effect of subsequent processing.

[0053] Preferably, in the dilute sulfuric acid solution, the mass ratio of sulfuric acid to water is 1-3:10-25.

[0054] Specifically, the pickling effect is best with the dilute sulfuric acid solution in this range.

[0055] Example 1

[0056] A passivation solution is composed of the following components: 12g benzotriazole derivative, 8g decamethylcyclopentasiloxane, 3g sodium molybdate, 3g sodium tungstate, 7g boron powder, 20mL hydrogen peroxide with a concentration of 30%(22.2g), 200mL deionized water.

[0057] A preparation method of the passivation solution includes the following steps:

[0058] (1) 12g of benzotriazole derivative powder is added to 100mL of deionized water, and after stirring uniformly, 8g of decamethylcyclopentasiloxane powder is slowly added to the benzotriazole derivative solution, and mechanical stirring is used to fully mix them, obtaining solution A;

[0059] (2) A heating furnace is used to keep the temperature of solution A at 50-60℃, 7g of boron powder is added to solution A, and stirred uniformly and completely dissolved;

[0060] (3) 3g of sodium molybdate and 3g of sodium tungstate powder are added to 100mL of deionized water, and fully stirred to form a solution. 100mL of the solution and 20mL of hydrogen peroxide with a concentration of 30% are added to the solution after the boron powder is completely dissolved by using a flow rod to form solution B, the temperature is kept at 50-60℃, and the passivation solution is obtained by stirring at 90Hz for 6-10 minutes by ultrasonic vibration.

[0061] The passivation of B30 cupronickel using the passivation solution of the present embodiment includes the following steps:

[0062] (1) First, the B30 cupronickel sample is subjected to pickling in a dilute sulfuric acid solution with a concentration of 10% for 30 min. After pickling, the sample is cleaned by immersion in deionized water. Then, the cupronickel sample is thoroughly ground and observed to ensure that the contaminants and oxide layers on the surface of the sample are removed;

[0063] (2) The pretreated B30 cupronickel sample is placed in the passivation solution, TTA passivation solution 1 and BTA passivation solution 2 on the market, respectively. The passivation temperature is 60°C, the pH value is 4, and the passivation treatment time is 20 min;

[0064] (3) The cupronickel sample treated in step (2) is dried at a temperature of 100°C, and a passivation film is formed on the surface of the cupronickel sample, and the passivation is completed. The surface morphology diagram of the surface treatment without passivation and the surface morphology diagram after surface treatment passivation are shown in Figure 1 、 2 respectively.

[0065] Note: During the passivation process, the passivation solution of the present embodiment and the passivation process of TTA passivation solution 1 and BTA passivation solution 2 on the market are consistent, including the initial state of the sample, the passivation time, the passivation temperature and the passivation method.

[0066] The samples passivated by the three passivation solutions are subjected to salt water immersion experiment analysis. The salt water immersion experiment can relatively accurately and truly reflect the corrosion resistance of the passivation film itself. The steps are as follows: immerse the samples in a 3.5% NaCl solution for 28 days, rinse and dry the corrosion products of the samples, and then weigh them. The mass difference before and after the experiment is used to calculate the corrosion weight loss or corrosion weight loss rate of the samples. The specific values are shown in Table 1.

[0067] Table 1 Corrosion weight loss of B30 cupronickel sample

[0068] Formulation Mass before corrosion / g Mass after corrosion / g Corrosion weight loss / g Corrosion weight loss rate Surface treatment only, no passivation 5.2359 5.2290 0.0069 0.132％ TTA passivation liquid 1 from the market 5.2384 5.2342 0.0042 0.080％ BTA passivation liquid 2 from the market 5.2378 5.2354 0.0024 0.046％ Passivation liquid of example 3 5.2362 5.2354 0.0008 0.015％

[0069] As can be seen from the salt water immersion experiment, the corrosion resistance of the sample passivated by the passivation solution of the present embodiment is greatly improved when passivating B30 cupronickel. The corrosion weight loss rate is only 18% to 40% of the products on the market, which is better than the copper passivation solution on the market and almost reaches the effect of chromate passivation solution.

[0070] Example 2

[0071] A passivation solution is composed of the following components: 6g benzotriazole derivative, 8g decamethylcyclopentasiloxane, 3g sodium molybdate, 6g sodium tungstate, 10g boron powder, 20mL hydrogen peroxide with a concentration of 30% (22.2g), and 200mL deionized water.

[0072] A method for preparing a passivation solution, comprising the following steps:

[0073] (1) 6 g of benzotriazole derivative powder is added to 100 mL of deionized water, after stirring uniformly, 8 g of decamethylcyclopentasiloxane powder is slowly added to the benzotriazole derivative solution, and it is fully mixed using mechanical stirring to obtain solution A;

[0074] (2) The temperature of solution A is maintained at 50-60°C using a heating furnace, 10 g of boron powder is added to solution A, and it is stirred uniformly and fully dissolved;

[0075] (3) 3 g of sodium molybdate and 6 g of sodium tungstate powder are added to 100 mL of deionized water, and fully stirred to form a solution, 100 mL of the solution and 20 mL of 30% concentration hydrogen peroxide are added to the solution after the boron powder is fully dissolved by using a flow rod to form solution B, the temperature is maintained at 50-60°C, and it is stirred at 90 Hz for 6-10 minutes by ultrasonic vibration to obtain the required passivation solution.

[0076] The passivation of B30 cupronickel using the passivation solution of the present embodiment comprises the following steps:

[0077] (1) First, the B30 cupronickel sample is subjected to pickling, pickling in a 10% concentration dilute sulfuric acid solution for 30 min, after pickling, the sample is soaked and cleaned using deionized water, and then the cupronickel sample is fully ground and observed to ensure that the contaminants and oxide layers on the surface of the cupronickel sample are removed;

[0078] (2) The pretreated B30 cupronickel sample is placed in the passivation solution, TTA passivation solution 1 and BTA passivation solution 2 on the market, respectively, the passivation temperature is 60°C, the pH value is 7, and the passivation treatment time is 60 min;

[0079] (3) The cupronickel sample treated in step (2) is dried at a temperature of 60°C, and a passivation film is obtained on the surface of the cupronickel sample, and the passivation is completed.

[0080] Note: During the passivation process, the passivation processes of the passivation solution of the present embodiment and the TTA passivation solution 1 and the BTA passivation solution 2 on the market are consistent, including the initial state of the sample, the passivation time, the passivation temperature and the passivation method.

[0081] The samples passivated by the three passivation solutions are subjected to salt water immersion test analysis, respectively. The salt water immersion test can relatively accurately and truly reflect the corrosion resistance of the passivation film itself. The steps are to immerse them in a 3.5% NaCl solution for 28 days, rinse and dry the corrosion products of the samples, and then weigh them, and calculate the corrosion weight loss or corrosion weight loss rate of the samples by the difference in mass before and after the experiment. The specific values are shown in Table 2.

[0082] Table 2B Corrosion weight loss table of B30 cupronickel samples

[0083] Formulation Mass before corrosion / g Mass after corrosion / g Corrosion weight loss / g Corrosion weight loss rate Surface treatment only, no passivation 5.2354 5.2287 0.0067 0.128％ TTA passivation liquid 1 from the market 5.2343 5.2304 0.0039 0.075％ BTA passivation liquid 2 from the market 5.2365 5.2344 0.0021 0.040％ Passivation liquid of example 3 5.2388 5.2381 0.0007 0.013％

[0084] As can be seen from the salt water immersion experiment, the passivation liquid of the present embodiment greatly improves the corrosion resistance of the B30 cupronickel sample during passivation, and the corrosion weight loss rate is only 17% to 40% of the products on the market, which is better than the copper passivation liquid on the market, and almost reaches the effect of chromate passivation liquid.

[0085] Example 3

[0086] A passivation liquid is composed of the following components: 5g benzotriazole derivative, 6g decamethylcyclopentasiloxane, 6g sodium molybdate, 3g sodium tungstate, 6g boron powder, 20mL hydrogen peroxide with a concentration of 30% (22.2g), and 200mL deionized water.

[0087] A preparation method of a passivation liquid includes the following steps:

[0088] (1) 5g of benzotriazole derivative powder is added to 100mL of deionized water, and after stirring uniformly, 6g of decamethylcyclopentasiloxane powder is slowly added to the benzotriazole derivative solution, and mechanical stirring is used to fully mix them, obtaining solution A;

[0089] (2) A heating furnace is used to keep the temperature of solution A at 50-60℃, 6g of boron powder is added to solution A, and after stirring uniformly and completely dissolving the boron powder;

[0090] (3) 6g of sodium molybdate and 3g of sodium tungstate powder are added to 100mL of deionized water, and after fully stirring, a solution is prepared, 100mL of the solution and 20mL of hydrogen peroxide with a concentration of 30% are added to the solution after the boron powder is completely dissolved by using a flow rod to form solution B, the temperature is kept at 50-60℃, and by using ultrasonic vibration, stirring is performed at 90Hz for 6-10 minutes to obtain the required passivation liquid.

[0091] The passivation of B30 cupronickel using the passivation liquid of the present embodiment includes the following steps:

[0092] (1) First, the B30 cupronickel sample is subjected to pickling in a dilute sulfuric acid solution with a concentration of 10% for 30min, and after pickling, the sample is immersed and cleaned with deionized water, and then the cupronickel sample is fully ground and observed to ensure that the contaminants and oxide layers on the surface of the cupronickel sample are removed;

[0093] (2) The pretreated B30 cupronickel sample is respectively placed in the passivation liquid, the TTA passivation liquid 1 and the BTA passivation liquid 2 on the market, the passivation temperature is 50℃, the pH value is 10, and the passivation treatment time is 30min;

[0094] (3) The cupronickel sample treated in step (2) is dried at a temperature of 80℃, and a passivation film is formed on the surface of the cupronickel sample, and the passivation is completed.

[0095] Note: In the passivation process, the passivation liquid of the present embodiment and the passivation process of TTA passivation liquid 1 and BTA passivation liquid 2 on the market are consistent, including the initial state of the sample, the passivation time, the passivation temperature and the passivation mode.

[0096] The samples passivated by the three passivation liquids respectively are subjected to salt water immersion experiment analysis. The salt water immersion experiment can relatively accurately and truly reflect the corrosion resistance of the passivation film itself. The steps are as follows: the samples are immersed in 3.5% NaCl solution for 28 days, the corrosion products of the samples are washed and dried, and then weighed. The mass difference before and after the experiment is used to calculate the corrosion weight loss or the corrosion weight loss rate of the sample. The specific values are shown in Table 3.

[0097] Table 3 Corrosion weight loss table of B30 cupronickel sample

[0098] Formulation Mass before corrosion / g Mass after corrosion / g Corrosion weight loss / g Corrosion weight loss rate Surface treatment only, no passivation 5.2379 5.2308 0.0071 0.136％ TTA passivation liquid 1 from the market 5.2375 5.233 0.0045 0.086％ BTA passivation liquid 2 from the market 5.2368 5.2342 0.0026 0.050％ Passivation liquid of example 3 5.2368 5.2389 0.0009 0.017％

[0099] It can be seen from the salt water immersion experiment that the corrosion resistance of the sample passivated by the passivation liquid of the present embodiment is greatly improved when passivating B30 cupronickel. The corrosion weight loss rate is only 19% to 40% of the products on the market, and the effect is better than that of the copper passivation liquid on the market, and almost reaches the effect of chromate passivation liquid.

[0100] The above examples are only illustrative of the present application and do not constitute a limitation on the protection scope of the present application. Any design identical or similar to the present application falls within the protection scope of the present application.

Claims

1. A passivation solution, characterized in that, By weight percentage, it consists of the following components Composition: 4.0-10.0% film-forming agent, 2.0-6.0% auxiliary film-forming agent, 1.0-10.0% oxidant, 2.0-6.0% boron powder, and the remainder is deionized water; the active ingredients of the film-forming agent are benzotriazole derivatives and decamethylcyclopentasiloxane, the active ingredients of the auxiliary film-forming agent are sodium molybdate and sodium tungstate, and the active ingredient of the oxidant is hydrogen peroxide.

2. The passivation solution as described in claim 1, characterized in that, The film-forming agent is a mixture of benzotriazole derivative, decamethylcyclopentasiloxane and deionized water, wherein the mass ratio of benzotriazole derivative to decamethylcyclopentasiloxane is 3-10:4-9.

3. The passivation solution as described in claim 1, characterized in that, The mass ratio of sodium molybdate to sodium tungstate in the auxiliary film-forming agent is 1-2:1-2.

4. A method for preparing a passivation solution according to any one of claims 1-3, characterized in that, Includes the following steps: (1) Add the prescribed amount of benzotriazole derivative and decamethylcyclopentasiloxane to deionized water and stir until homogeneous to form solution A; (2) Add the boron powder of the formula amount to solution A, heat the mixture to 50-60℃, stir evenly and completely dissolve the boron powder; (3) Add the formulated amount of auxiliary film-forming agent and oxidant to the solution after the boron powder is completely dissolved to form solution B. Stir solution B at 50-60℃ until it is homogeneous and fully reacted to obtain passivation solution.

5. A passivation method for using the passivation solution according to any one of claims 1-3 for passivating cupronickel, characterized in that, Includes the following steps: (1) First, the surface of the cupronickel sample is pretreated to remove contaminants and oxide layer from the surface of the cupronickel sample; (2) Place the pretreated white copper sample into the passivation solution, with a passivation temperature of 25-60℃, a pH value of 4-10, and a passivation time of 5-60 min; (3) The cupronickel sample treated in step (2) is dried at a temperature of 60 to 100°C to obtain a passivation film on the surface of the cupronickel sample, thus completing the passivation.

6. The passivation method as described in claim 5, characterized in that, In step (2), the copper sample is required to be completely immersed during passivation and stirred using ultrasonic vibration.

7. The passivation method as described in claim 5, characterized in that, The surface pretreatment includes grinding and pickling.

8. The passivation method as described in claim 7, characterized in that, The pickling process requires the cupronickel sample to be completely immersed and continuously agitated.

9. The passivation method as described in claim 7, characterized in that, The pickling process uses a dilute sulfuric acid solution.

10. The passivation method as described in claim 9, characterized in that, In the dilute sulfuric acid solution, the mass ratio of sulfuric acid to water is 1-3:10-25.

Images