A salt spray resistant, high temperature resistant, chromium-free passivating agent for copper parts and its preparation method.

Abstract

This invention relates to the technical field of metal surface treatment, and more particularly to a chromium-free passivating agent for copper parts that is resistant to salt spray and high temperature, and its preparation method. The passivating agent is prepared from raw materials including aminated boron nitride nanosheets, a silane coupling agent, an isohydroxamic acid-functionalized silsesquioxane hybrid film-forming corrosion inhibitor, a triazole derivative, a repair agent, a nonionic surfactant, and a pH adjuster. Using this passivating agent to treat copper workpieces results in good passivation performance, enabling the passivated copper workpieces to exhibit good resistance to salt spray and high-temperature oxidation.

Description

Technical Field

[0001] This invention relates to the technical field of metal surface treatment, and in particular to a salt spray resistant, high temperature resistant, chromium-free passivating agent for copper parts and its preparation method. Background Technology

[0002] Copper and its alloys are among the earliest utilized metallic materials, and their excellent electrical and thermal conductivity, as well as ductility, make them important in fields such as power electronics, communication equipment, and high-end equipment manufacturing. However, copper is chemically reactive and readily undergoes electrochemical corrosion and oxidation discoloration in humid atmospheres, chloride-containing environments, and high temperatures, severely affecting its performance. Traditional copper purification processes often employ chromate treatment, which forms a dense chromate conversion film on the copper surface, providing excellent protection. However, hexavalent chromium is highly toxic and carcinogenic, posing a significant threat to the environment and human health, thus its use is strictly limited. Therefore, developing efficient and environmentally friendly chromium-free passivating agents has become a key research focus.

[0003] Currently, commonly used chromium-free passivation technologies mainly include silane treatment, molybdate treatment, and organic corrosion inhibitor treatment. Among them, organic corrosion inhibitors can form polymeric coordination compounds with copper ions and adsorb onto the copper surface, thus playing a role in corrosion inhibition. Chinese Patent No. CN108796489B discloses a chromium-free passivation agent suitable for copper and copper alloys with nano-self-healing multi-level dense structure and its preparation process. The chromium-free passivation agent is prepared using raw materials including inorganic salts, organic corrosion inhibitors, nano-film-forming agents, film-forming promoters, and wetting agents, which can form a multi-level dense passivation layer on the surface of copper and its alloys to achieve the purpose of corrosion inhibition. Chinese patent application CN103556142A discloses an environmentally friendly passivation solution and method for copper and copper alloy surfaces. The solvent is water or ethanol, and the solute contains NC heterocyclic compounds and pyrophosphates. This solute can undergo a self-assembly reaction with copper and copper alloys, forming a dense monolayer film on the surface, thus achieving passivation. However, single organic corrosion inhibitors have limited protective effects under harsh salt spray or high-temperature environments, often exhibiting problems such as insufficient film density, poor adhesion, and poor high-temperature resistance. Therefore, developing an environmentally friendly passivating agent that can form multiple protective functions and has superior overall performance is a technical challenge urgently needing to be solved by those skilled in the art. Summary of the Invention

[0004] To solve at least one of the above problems, the present invention provides a method for preparing a salt spray resistant and high temperature resistant chromium-free passivating agent for copper parts, comprising the following steps: S100, a premixed solution is obtained by mixing raw materials including aminated boron nitride nanosheets and silane coupling agents; S200. Add raw materials including isohydroxamic acid-functionalized silsesquioxane hybrid film-forming corrosion inhibitor and triazole derivative to the premixed solution and mix to obtain a mixed solution; S300. Add raw materials including a repair agent, a nonionic surfactant, and a pH adjuster to the mixture to prepare the passivating agent.

[0005] Further, the preparation method of the isohydroxamic acid functionalized silsesquioxane hybrid film-forming corrosion inhibitor is as follows: Under a nitrogen atmosphere, aminopropyl heptaisobutyl cage-like polysilsesquioxane is added to anhydrous tetrahydrofuran, mixed evenly, and then placed in an ice-water bath to cool to 0-5°C. Triethylamine is added to it while stirring, and then a mixed solution of isobutyryl chloride and anhydrous tetrahydrofuran is added dropwise. After the dropwise addition is completed, the temperature is raised to room temperature and the reaction is continued to be stirred for 12-16 hours to obtain a crude product. After purification, a white solid is obtained. After mixing with hydroxylamine methanol suspension, the temperature is raised to 60-65°C and refluxed for 6-8 hours. After secondary purification, the isohydroxamic acid functionalized silsesquioxane hybrid film-forming corrosion inhibitor is obtained.

[0006] Furthermore, the preparation method of the hydroxylamine methanol suspension is as follows: hydroxylamine hydrochloride is added to methanol and stirred until dissolved, then placed in an ice-water bath, and a methanol solution containing sodium hydroxide is added dropwise. After the addition is completed, the hydroxylamine methanol suspension is obtained.

[0007] Furthermore, the triazole derivative is one or more of benzotriazole, methylbenzotriazole, and carboxybenzotriazole.

[0008] Further, the preparation method of the repair agent is as follows: Mg(NO3)2·6H2O and Al(NO3)3·9H2O are added to deionized water and stirred until dissolved. Under nitrogen atmosphere and stirring, a sodium hydroxide solution containing Na2MoO4 is added to the solution, and the pH is controlled at 10±0.2. After the addition is complete, the solution is crystallized at 60-70℃ for 24 hours. After centrifugation, washing and drying, a white powder is obtained, which is the repair agent.

[0009] Furthermore, the nonionic surfactant is one or more of alkylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, and polyether-modified siloxane.

[0010] Furthermore, the silane coupling agent is an aminosilane coupling agent or an epoxysilane coupling agent.

[0011] The present invention also includes a salt spray resistant and high temperature resistant chromium-free passivating agent for copper parts, which is prepared by the preparation method of a salt spray resistant and high temperature resistant chromium-free passivating agent for copper parts as described in any of the above technical solutions.

[0012] This invention also includes the application of a salt spray resistant, high temperature resistant, chromium-free passivating agent for copper parts in the treatment of copper workpieces, comprising the following steps: A1. The copper workpiece is degreased, washed with water, acid-washed and activated, and then washed a second time to obtain a clean workpiece. A2. Immerse the cleaned workpiece in the passivating agent and treat it at 40-50℃ for 6-10 minutes; A3. Remove the workpiece, wash it with water, and dry it at 90-120℃ for 20-30 minutes.

[0013] The present invention has the following beneficial effects: In this invention, the aminated boron nitride nanosheets possess excellent chemical inertness and high-temperature stability, effectively dispersing the thermal stress of the film. The isohydroxamic acid-functionalized silsesquioxane, with its cage-like polysilsesquioxane structure, provides a rigid framework, endowing the film with excellent hardness, thermal stability, and dimensional stability. The isohydroxamic acid group is a strong metal chelating group, exhibiting extremely high coordination ability for copper ions, and can form a robust chemisorption layer on the copper substrate surface. The triazole derivative can rapidly adsorb onto the copper surface to form a polymer film, synergistically working with the isohydroxamic acid-functionalized silsesquioxane hybrid film-forming corrosion inhibitor to form a denser and more complete chemisorption layer on the copper surface. Compared with the use of triazole derivatives alone in the prior art, the present invention combines triazole derivatives with components such as isohydroxamic acid-functionalized silsesquioxane and amino boron nitride nanosheets to successfully construct a multifunctional composite protective film on the surface of copper workpieces. This film not only has a good corrosion inhibition effect, but also improves the high temperature resistance of the passivation film, thus solving the problem of insufficient high temperature resistance of existing triazole corrosion inhibitors. Detailed Implementation

[0014] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the embodiments of this application. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0015] Copper and copper alloys are widely used in electronics and electrical fields due to their excellent electrical and thermal conductivity and ductility. However, copper is prone to corrosion and oxidation discoloration in humid, salt spray, or high-temperature environments, affecting its performance. Therefore, passivation treatment of copper parts to improve their corrosion resistance is crucial. Traditional copper passivation processes often use chromates, but their use is limited due to their significant environmental hazards. Therefore, this invention provides a chromium-free passivating agent for copper parts that is resistant to salt spray and high temperatures, and its preparation method, comprising the following steps: S100, a premixed solution is obtained by mixing raw materials including aminated boron nitride nanosheets and silane coupling agents; S200. Add raw materials including isohydroxamic acid-functionalized silsesquioxane hybrid film-forming corrosion inhibitor and triazole derivative to the premixed solution and mix to obtain a mixed solution; S300. Add raw materials including a repair agent, a nonionic surfactant, and a pH adjuster to the mixture to prepare the passivating agent.

[0016] Specifically, the process involves: S100. Add 5-8 parts by weight of aminated boron nitride nanosheets, 1.2-2 parts by weight of silane coupling agent and 65-80 parts by weight of water to the reactor, raise the temperature to 35-45℃, and stir at 300-500 r / min for 20-40 min to obtain a premixed solution. S200. Add 8-15 parts by weight of isohydroxamic acid-functionalized silsesquioxane hybrid film-forming corrosion inhibitor and 2-5 parts by weight of triazole derivative to 100 parts by weight of premixed solution, raise the temperature to 30-40℃, and stir at 400-600 r / min for 40-60 min to obtain the mixture. S300: Add 3-6 parts by weight of repair agent and 0.3-0.8 parts by weight of nonionic surfactant to 100 parts by weight of the mixture, raise the temperature to 35-45℃, stir at 300-500 r / min for 60-80 min, add pH adjuster to adjust the pH value of the system to 3.5-5.5, and stir evenly to obtain the passivating agent.

[0017] In step S100, aminated boron nitride (particle size 50-100 nm) can be purchased commercially or prepared. The preparation method is as follows: Dissolve 50 g of urea in 500 mL of deionized water, stir and mix thoroughly to obtain a urea solution. Add 0.8 g of 3 mm diameter zirconia grinding beads and 1.5 g of hexagonal boron nitride powder to the solution, stir thoroughly, and then ball mill under ultrasonic conditions for 40 h. After ball milling, centrifuge the milling liquid, remove the supernatant, wash three times with water, and vacuum dry the washed product at 80 °C for 24 h to obtain the final product.

[0018] In this step, the aminated boron nitride nanosheets exhibit excellent chemical inertness and high-temperature stability, laying the foundation for the salt spray resistance and high-temperature resistance of the subsequent passivation film. Their surface contains a large number of amino groups, and the silane coupling agent molecules contain alkoxy groups and active functional groups. Under the action of water, the silane coupling agent undergoes hydrolysis, and the alkoxy groups are converted into hydrophilic silanol groups, which interact with the amino groups on the surface of the aminated boron nitride nanosheets through hydrogen bonding and other interactions, so that they are uniformly dispersed in the silane system and their aggregation is avoided.

[0019] In step S200, the cage-like polysilsesquioxane provides a rigid framework, imparting excellent hardness, thermal stability, and dimensional stability to the film. The isohydroxamic acid group is a strong metal chelating group with extremely high coordination ability for copper ions, forming a robust chemisorption layer on the copper substrate surface. The presence of the long organic chain imparts a certain degree of flexibility to the film and enhances its compatibility with subsequent organic systems. The triazole derivative can rapidly adsorb onto the copper surface to form a polymeric film, synergistically working with the isohydroxamic acid-functionalized silsesquioxane hybrid film-forming corrosion inhibitor to form a denser and more complete chemisorption layer on the copper surface.

[0020] In step S300, the repair agent has a layered structure and ion exchange capacity. When the passivation film experiences minor damage, the MoO4 in the repair agent... 2- It will release slowly, reacting with Cu on the copper surface. 2+ A stable molybdate precipitate is formed, filling in the damaged areas and enabling the passivation film to self-repair. The nonionic surfactant reduces the surface tension of the system, improves the wettability of the passivating agent on the copper workpiece surface, and ensures that the passivating agent can be evenly coated on the copper surface, avoiding incomplete plating or localized insufficient passivation.

[0021] The preparation method of the isohydroxamic acid-functionalized silsesquioxane hybrid film-forming corrosion inhibitor is as follows: Under a nitrogen atmosphere, 7-12 parts by weight of aminopropylheptaisobutyl cage-like polysilsesquioxane are added to 100 parts by weight of anhydrous tetrahydrofuran. After mixing evenly, the mixture is placed in an ice-water bath and cooled to 0-5°C. The mixture is stirred at a speed of 200-300 r / min. While stirring, 8-12 parts by weight of triethylamine are added. After stirring for 10-15 min, the mixture is slowly added dropwise. A mixed solution consisting of 8-15 parts by weight of isobutyryl chloride and 35-45 parts by weight of anhydrous tetrahydrofuran was added dropwise. After the addition was complete, the temperature was raised to room temperature and the reaction was continued with stirring for 12-16 hours to obtain a crude product. After purification, a white solid was obtained. This solid was mixed with 55-65 parts by weight of hydroxylamine methanol suspension and the temperature was raised to 60-65℃. The mixture was refluxed for 6-8 hours. After the reaction was completed, the isohydroxamic acid functionalized silsesquioxane hybrid film-forming corrosion inhibitor was obtained through secondary purification.

[0022] In this step, the aminopropyl heptaisobutyl cage-like polysilsesquioxane (purity ≥98%) molecule contains an amino group, and the isobutyryl chloride molecule contains an acyl chloride group. Under the conditions of triethylamine as a catalyst and anhydrous tetrahydrofuran as a solvent, the two undergo a nucleophilic substitution reaction to form an amide bond. The ice-water bath condition helps control the reaction temperature, preventing the reaction from becoming too vigorous and avoiding hydrolysis of the isobutyryl chloride; the presence of triethylamine promotes the reaction in the forward direction. The purified white solid molecule contains an amide group. The hydroxylamine in the hydroxylamine methanol suspension is nucleophilic; under reflux conditions, the amide group reacts with the hydroxylamine to form an isohydroxamic acid group. After secondary purification, an isohydroxamic acid-functionalized silsesquioxane hybrid film-forming corrosion inhibitor is obtained. The cage-like structure of the silsesquioxane exhibits excellent high-temperature resistance and structural stability, maintaining its structure unchanged under high-temperature environments and preventing the decomposition of the passivation film. The hydroxamic acid group has a strong chelating ability and can form a stable chelate with copper ions to build a dense film layer, effectively blocking the intrusion of corrosive media. At the same time, the silanol groups in the silsesquioxane molecule can undergo condensation reactions with silane coupling agents and amino boron nitride nanosheets, improving the density and adhesion of the passivation film and achieving a synergistic effect of film formation and corrosion inhibition.

[0023] The preparation method of the hydroxylamine methanol suspension is as follows: 12-16 parts of hydroxylamine hydrochloride are added to 100 parts by weight of methanol and stirred until dissolved. The solution is placed in an ice-water bath, and a methanol solution containing sodium hydroxide (12-18 parts by weight of sodium hydroxide are added to 35-45 parts by weight of methanol solution) is added dropwise while stirring. After the addition is completed, stirring is continued for 6-10 minutes to obtain the hydroxylamine methanol suspension.

[0024] In this process, ice-water bath conditions can prevent the decomposition of hydroxylamine, while reducing the solubility of sodium chloride in methanol, promoting the precipitation of sodium chloride, and improving the purity of hydroxylamine.

[0025] The triazole derivative is one or more of benzotriazole, methylbenzotriazole, and carboxybenzotriazole. A synergistic corrosion inhibition effect exists between the triazole derivative and the isohydroxamic acid-functionalized silsesquioxane hybrid film-forming corrosion inhibitor. The isohydroxamic acid group forms a chelate with copper ions to construct a film layer. The triazole derivative adsorbs on the surface of the film layer, further filling the micropores of the film layer, while simultaneously inhibiting localized corrosion on the copper surface. The synergistic effect of both significantly improves the corrosion inhibition performance and stability of the passivation film.

[0026] The preparation method of the repair agent is as follows: Mg(NO3)2·6H2O and Al(NO3)3·9H2O are added to deionized water and stirred until dissolved. Under nitrogen atmosphere and stirring, sodium hydroxide solution containing Na2MoO4 is added to the solution, and the pH is controlled at 10±0.2. After the addition is completed, the solution is crystallized at 60-70℃ for 24 hours. After centrifugation, washing and drying, a white powder is obtained, which is the repair agent.

[0027] In this process, under alkaline conditions, layered bimetallic hydroxides are formed via co-precipitation, while molybdate anions are simultaneously embedded in the interlayer to form a complex hydroxide precipitate. A nitrogen atmosphere prevents Al from being deposited. 3+ Oxidation ensures product purity; controlling the pH within a certain range ensures the purity of Mg. 2+ Al 3+ Complete precipitation, while ensuring MoO4 2- It can be successfully embedded in the interlayer to form a stable layered structure. When the passivation film suffers minor damage, corrosive media can penetrate the damaged area, causing a change in the pH value at the damaged site. This triggers interlayer ion exchange in the repair agent, and the MoO4 in the repair agent... 2- It will slowly release Cu, which dissolves on the copper surface. 2+ A stable copper molybdate precipitate is formed, filling the damaged areas of the passivation film and forming a new protective layer, thereby achieving self-repair of the passivation film and preventing further corrosion.

[0028] The nonionic surfactant is one or more of alkylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, and polyether-modified siloxane. The addition of the nonionic surfactant reduces the surface tension of the system, improves the wetting properties of the passivating agent, and allows the passivating agent to quickly and uniformly cover the surface of the copper workpiece, especially in complex areas such as gaps and grooves, avoiding incomplete plating or localized insufficient passivation, and ensuring the integrity of the passivation film. Simultaneously, due to the amphiphilic nature of the nonionic surfactant, it can improve the compatibility of the components, thereby enhancing the density and stability of the passivation film.

[0029] The silane coupling agent is an aminosilane coupling agent or an epoxysilane coupling agent. Preferably, it is one or more of KH-550, KH-560, KH-540, and KH-570.

[0030] A salt spray resistant and high temperature resistant chromium-free passivating agent for copper parts is prepared by the preparation method of a salt spray resistant and high temperature resistant chromium-free passivating agent for copper parts as described in any of the above technical solutions.

[0031] The application of a salt spray resistant, high-temperature resistant, chromium-free passivating agent for copper parts in the treatment of copper workpieces includes the following steps: A1. The copper workpiece is degreased, washed with water, acid-washed and activated, and then washed a second time to obtain a clean workpiece. Degreasing involves using an alkaline degreasing agent at 50-60℃ for 6-10 minutes with a stirring speed of 150-200 rpm to remove oil and dust from the surface. Washing involves rinsing with running water for 1-2 minutes to remove residual degreasing agent. Acid-washing and activation involves using 5% dilute sulfuric acid at 25-35℃ for 1-3 minutes with a stirring speed of 100-150 rpm to remove the oxide layer from the surface. Secondary washing involves rinsing with running water for 2-3 minutes to remove residual dilute sulfuric acid and prevent the acid from affecting the subsequent passivation reaction. The alkaline degreasing agent is prepared by adding 6-10 parts by weight of sodium hydroxide, 3-5 parts by weight of sodium carbonate, 2-4 parts by weight of trisodium phosphate, and 0.5-1 parts by weight of a nonionic surfactant to 100 parts by weight of water and mixing thoroughly. A2. Immerse the cleaned workpiece in the passivating agent and treat it at 40-50℃ for 6-10 minutes; A3. Remove the workpiece, rinse it with running water for 1-2 minutes to remove any residual passivating agent from the workpiece surface, and then place it in an oven and dry it at 90-120℃ for 20-30 minutes.

[0032] Preparation Example 1-1 The preparation method of the isohydroxamic acid-functionalized silsesquioxane hybrid film-forming corrosion inhibitor is as follows: Under a nitrogen atmosphere, 10 parts by weight of aminopropylheptaisobutyl cage-like polysilsesquioxane are added to 100 parts by weight of anhydrous tetrahydrofuran. After mixing evenly, the mixture is placed in an ice-water bath and cooled to 0°C. The mixture is stirred at a speed of 300 r / min. While stirring, 10 parts by weight of triethylamine are added. After stirring for 15 min, a mixed solution obtained by mixing 12 parts by weight of isobutyryl chloride and 42 parts by weight of anhydrous tetrahydrofuran is slowly added dropwise. After the addition is complete... Then, the temperature was raised to room temperature and the reaction was stirred for 14 hours to obtain a crude product. Most of the solvent in the crude product was removed by vacuum distillation. 100 mL of ethanol was added to the residue, and the mixture was stirred and filtered. The filter cake was washed three times with ethanol and dried under vacuum at 60 °C to obtain a white solid. The solid was mixed with 60 parts by weight of hydroxylamine methanol suspension and the temperature was raised to 65 °C and refluxed for 8 hours. After the reaction was completed, methanol was removed by vacuum distillation. The residue was washed with deionized water, filtered, and dried under vacuum at 60 °C to obtain isohydroxamic acid functionalized silsesquioxane hybrid film-forming corrosion inhibitor.

[0033] The preparation method of hydroxylamine methanol suspension is as follows: 14 parts of hydroxylamine hydrochloride are added to 100 parts by weight of methanol and stirred until dissolved. The solution is placed in an ice-water bath, and a methanol solution containing sodium hydroxide (14 parts by weight of sodium hydroxide are added to 42 parts by weight of methanol solution) is added dropwise while stirring. After the addition is completed, stirring is continued for 8 minutes to obtain hydroxylamine methanol suspension.

[0034] Preparation Examples 1-2 The preparation method of the isohydroxamic acid-functionalized silsesquioxane hybrid film-forming corrosion inhibitor is as follows: Under a nitrogen atmosphere, 7 parts by weight of aminopropylheptaisobutyl cage-like polysilsesquioxane are added to 100 parts by weight of anhydrous tetrahydrofuran. After mixing evenly, the mixture is placed in an ice-water bath and cooled to 0°C. The mixture is stirred at a speed of 200 r / min. While stirring, 8 parts by weight of triethylamine are added. After stirring for 10 min, a mixed solution obtained by mixing 8 parts by weight of isobutyryl chloride and 35 parts by weight of anhydrous tetrahydrofuran is slowly added dropwise. After the addition is complete... The mixture was heated to room temperature and stirred for 12 hours to obtain a crude product. Most of the solvent was removed by vacuum distillation of the crude product. 100 mL of ethanol was added to the residue, and the mixture was stirred and filtered. The filter cake was washed three times with ethanol and dried under vacuum at 60 °C to obtain a white solid. The solid was mixed with 55 parts by weight of hydroxylamine methanol suspension and the temperature was raised to 60 °C and refluxed for 6 hours. After the reaction was completed, methanol was removed by vacuum distillation. The residue was washed with deionized water, filtered, and dried under vacuum at 60 °C to obtain an isohydroxyoxime-functionalized silsesquioxane hybrid film-forming corrosion inhibitor.

[0035] The preparation method of hydroxylamine methanol suspension is as follows: 12 parts of hydroxylamine hydrochloride are added to 100 parts by weight of methanol and stirred until dissolved. The solution is placed in an ice-water bath, and a methanol solution containing sodium hydroxide (12 parts by weight of sodium hydroxide are added to 35 parts by weight of methanol solution) is added dropwise while stirring. After the addition is completed, stirring is continued for 6 minutes to obtain hydroxylamine methanol suspension.

[0036] Preparation Examples 1-3 The preparation method of the isohydroxamic acid-functionalized silsesquioxane hybrid film-forming corrosion inhibitor is as follows: Under a nitrogen atmosphere, 12 parts by weight of aminopropylheptaisobutyl cage-like polysilsesquioxane are added to 100 parts by weight of anhydrous tetrahydrofuran. After mixing evenly, the mixture is placed in an ice-water bath and cooled to 5°C. The mixture is stirred at 300 r / min. While stirring, 12 parts by weight of triethylamine are added. After stirring for 15 min, a mixed solution obtained by mixing 15 parts by weight of isobutyryl chloride and 45 parts by weight of anhydrous tetrahydrofuran is slowly added dropwise. After the addition is complete... Then, the temperature was raised to room temperature and the reaction was stirred for 16 hours to obtain a crude product. Most of the solvent in the crude product was removed by vacuum distillation. 100 mL of ethanol was added to the residue, and the mixture was stirred and filtered. The filter cake was washed three times with ethanol and dried under vacuum at 60 °C to obtain a white solid. The solid was mixed with 65 parts by weight of hydroxylamine methanol suspension and the temperature was raised to 65 °C and refluxed for 8 hours. After the reaction was completed, methanol was removed by vacuum distillation. The residue was washed with deionized water, filtered, and dried under vacuum at 60 °C to obtain isohydroxamic acid functionalized silsesquioxane hybrid film-forming corrosion inhibitor.

[0037] The preparation method of hydroxylamine methanol suspension is as follows: 16 parts of hydroxylamine hydrochloride are added to 100 parts by weight of methanol and stirred until dissolved. The solution is placed in an ice-water bath, and a methanol solution containing sodium hydroxide (18 parts by weight of sodium hydroxide are added to 45 parts by weight of methanol solution) is added dropwise while stirring. After the addition is completed, stirring is continued for 10 minutes to obtain hydroxylamine methanol suspension.

[0038] Preparation Example 2-1 The preparation method of the repair agent is as follows: Add 10 parts by weight of Mg(NO3)2·6H2O and 12 parts by weight of Al(NO3)3·9H2O to 100 parts by weight of deionized water and stir until dissolved. Under nitrogen atmosphere and stirring, add sodium hydroxide solution containing Na2MoO4 (add 5 parts by weight of Na2MoO4 to 25 parts by weight of 5% sodium hydroxide solution), control the pH to 10±0.2. After the addition is complete, crystallize at 65℃ for 24h, centrifuge at 4000r / min for 12min to obtain the precipitate, wash with deionized water until the washing solution is neutral, and then dry at 80℃ for 4h to obtain a white powder, which is the repair agent.

[0039] Preparation Example 2-2 The preparation method of the repair agent is as follows: Add 8 parts by weight of Mg(NO3)2·6H2O and 10 parts by weight of Al(NO3)3·9H2O to 100 parts by weight of deionized water and stir until dissolved. Under nitrogen atmosphere and stirring, add sodium hydroxide solution containing Na2MoO4 (add 3 parts by weight of Na2MoO4 to 20 parts by weight of 5% sodium hydroxide solution), control the pH to 10±0.2. After the addition is complete, crystallize at 65℃ for 24h, centrifuge at 4000r / min for 12min to obtain the precipitate, wash with deionized water until the washing solution is neutral, and then dry at 80℃ for 4h to obtain a white powder, which is the repair agent.

[0040] Preparation Examples 2-3 The preparation method of the repair agent is as follows: Add 15 parts by weight of Mg(NO3)2·6H2O and 18 parts by weight of Al(NO3)3·9H2O to 100 parts by weight of deionized water and stir until dissolved. Under nitrogen atmosphere and stirring, add sodium hydroxide solution containing Na2MoO4 (8 parts by weight of Na2MoO4 added to 28 parts by weight of 5% sodium hydroxide solution), control the pH to 10±0.2. After the addition is complete, crystallize at 65℃ for 24h, centrifuge at 4000r / min for 12min to obtain precipitate, wash with deionized water until the washing solution is neutral, and then dry at 80℃ for 4h to obtain white powder, which is the repair agent.

[0041] Example 1 A method for preparing a salt spray resistant and high-temperature resistant chromium-free passivating agent for copper parts includes the following steps: S100, add 7.2 parts by weight of aminated boron nitride nanosheets, 1.8 parts by weight of silane coupling agent KH560 and 72 parts by weight of water to the reactor, raise the temperature to 40°C, and stir at 400 r / min for 30 min to obtain a premixed solution; S200. Add 12 parts by weight of the isohydroxamic acid-functionalized silsesquioxane hybrid film-forming corrosion inhibitor prepared in Preparation Example 1-1 and 4.2 parts by weight of benzotriazole to 100 parts by weight of the premixed solution. Raise the temperature to 35°C and stir at 500 r / min for 50 min to obtain the mixture. S300. Add 4.5 parts by weight of the repair agent prepared in Preparation Example 2-1 and 0.6 parts by weight of fatty alcohol polyoxyethylene ether AEO-7 to 100 parts by weight of the mixture, raise the temperature to 40°C, stir at 400 r / min for 70 min, add citric acid as a pH adjuster to adjust the pH value of the system to 4.5, and stir evenly to obtain the passivating agent.

[0042] The application of the above passivating agent in the treatment of copper workpieces includes the following steps: A1. The copper workpiece is degreased, washed with water, acid-washed and activated, and then washed a second time to obtain a clean workpiece. Degreasing involves using an alkaline degreasing agent at 55℃ for 8 minutes with a stirring speed of 180 rpm to remove oil and dust from the surface of the copper workpiece. Washing involves rinsing with running water for 2 minutes to remove residual degreasing agent from the workpiece surface. Acid-washing and activation involves using 5% dilute sulfuric acid at 30℃ for 2 minutes with a stirring speed of 120 rpm to remove the oxide layer from the surface of the copper workpiece. The second water wash involves rinsing with running water for 3 minutes to remove residual dilute sulfuric acid from the workpiece surface, preventing the acid from affecting the subsequent passivation reaction. The alkaline degreasing agent is prepared by adding 8 parts by weight of sodium hydroxide, 4 parts by weight of sodium carbonate, 3 parts by weight of trisodium phosphate, and 0.8 parts by weight of fatty alcohol polyoxyethylene ether AEO-7 to 100 parts by weight of water and mixing thoroughly. A2. Immerse the cleaned workpiece in the prepared passivating agent and treat it at 45°C for 8 minutes; A3. Remove the workpiece, rinse it with running water for 2 minutes to remove the passivating agent remaining on the surface of the workpiece, and then place it in an oven and dry it at 100℃ for 25 minutes.

[0043] Example 2 A method for preparing a salt spray resistant and high-temperature resistant chromium-free passivating agent for copper parts includes the following steps: S100. Add 5 parts by weight of aminated boron nitride nanosheets, 1.2 parts by weight of silane coupling agent KH560 and 65 parts by weight of water to the reactor, raise the temperature to 35°C, and stir at 300 r / min for 20 min to obtain a premixed solution. S200. Add 8 parts by weight of the isohydroxamic acid-functionalized silsesquioxane hybrid film-forming corrosion inhibitor prepared in Preparation Example 1-1 and 2 parts by weight of benzotriazole to 100 parts by weight of the premixed solution. Raise the temperature to 30°C and stir at 400 r / min for 40 min to obtain the mixture. S300. Add 3 parts by weight of the repair agent prepared in Preparation Example 2-1 and 0.3 parts by weight of fatty alcohol polyoxyethylene ether AEO-7 to 100 parts by weight of the mixture, raise the temperature to 35°C, stir at 300 r / min for 60 min, add citric acid as a pH adjuster, adjust the pH value of the system to 4.5, and stir evenly to obtain the passivating agent.

[0044] The application of passivating agents in the treatment of copper workpieces refers to the relevant steps in Example 1.

[0045] Example 3 A method for preparing a salt spray resistant and high-temperature resistant chromium-free passivating agent for copper parts includes the following steps: S100. Add 8 parts by weight of aminated boron nitride nanosheets, 2 parts by weight of silane coupling agent KH560 and 80 parts by weight of water to the reactor, raise the temperature to 45°C, and stir at 500 r / min for 40 min to obtain a premixed solution. S200. Add 15 parts by weight of the isohydroxamic acid-functionalized silsesquioxane hybrid film-forming corrosion inhibitor prepared in Preparation Example 1-1 and 5 parts by weight of benzotriazole to 100 parts by weight of the premixed solution. Raise the temperature to 40°C and stir at 600 r / min for 60 min to obtain the mixture. S300. Add 6 parts by weight of the repair agent prepared in Preparation Example 2-1 and 0.8 parts by weight of fatty alcohol polyoxyethylene ether AEO-7 to 100 parts by weight of the mixture, raise the temperature to 45°C, stir at 500 r / min for 80 min, add citric acid as a pH adjuster to adjust the pH value of the system to 4.5, and stir evenly to obtain the passivating agent.

[0046] The application of passivating agents in the treatment of copper workpieces refers to the relevant steps in Example 1.

[0047] Example 4 A method for preparing a salt spray resistant and high-temperature resistant chromium-free passivating agent for copper parts includes the following steps: S100, add 6.5 parts by weight of aminated boron nitride nanosheets, 1.4 parts by weight of silane coupling agent KH560 and 68 parts by weight of water to the reactor, raise the temperature to 40°C, and stir at 400 r / min for 30 min to obtain a premixed solution; S200. Add 10 parts by weight of the isohydroxamic acid-functionalized silsesquioxane hybrid film-forming corrosion inhibitor prepared in Preparation Example 1-1 and 3.5 parts by weight of benzotriazole to 100 parts by weight of the premixed solution. Raise the temperature to 35°C and stir at 500 r / min for 50 min to obtain the mixture. S300. Add 3.5 parts by weight of the repair agent prepared in Preparation Example 2-1 and 0.4 parts by weight of fatty alcohol polyoxyethylene ether AEO-7 to 100 parts by weight of the mixture, raise the temperature to 40°C, stir at 400 r / min for 70 min, add citric acid as a pH adjuster to adjust the pH value of the system to 4.5, and stir evenly to obtain the passivating agent.

[0048] The application of passivating agents in the treatment of copper workpieces refers to the relevant steps in Example 1.

[0049] Comparative Example 1 Compared with Example 1, this comparative example does not add aminated boron nitride nanosheets in the preparation of the passivating agent, while all other aspects are the same as in Example 1.

[0050] The application of passivating agents in the treatment of copper workpieces refers to the relevant steps in Example 1.

[0051] Comparative Example 2 Compared with Example 1, this comparative example does not add isohydroxamic acid-functionalized silsesquioxane hybrid film-forming corrosion inhibitor during the preparation of the passivating agent; all other aspects are the same as in Example 1.

[0052] The application of passivating agents in the treatment of copper workpieces refers to the relevant steps in Example 1.

[0053] Comparative Example 3 Compared with Example 1, in the preparation of the passivating agent, the isohydroxamic acid-functionalized silsesquioxane hybrid film-forming corrosion inhibitor was replaced with aminopropyl heptaisobutyl cage-like polysilsesquioxane, and the rest were the same as in Example 1.

[0054] The application of passivating agents in the treatment of copper workpieces refers to the relevant steps in Example 1.

[0055] Comparative Example 4 Compared with Example 1, this comparative example does not add benzotriazole in the preparation of the passivating agent, while all other aspects are the same as in Example 1.

[0056] The application of passivating agents in the treatment of copper workpieces refers to the relevant steps in Example 1.

[0057] Comparative Example 5 Compared with Example 1, this comparative example does not add a repair agent during the preparation of the passivating agent, while all other aspects are the same as in Example 1.

[0058] The application of passivating agents in the treatment of copper workpieces refers to the relevant steps in Example 1.

[0059] Related tests: The copper workpiece used for the test sample was T3 copper (99.7% Cu, the rest being impurities), and the sample size was 100mm×100mm×1mm.

[0060] Neutral salt spray test: Referring to the relevant standards in GB / T10125-2021, the copper workpieces of each embodiment and comparative example after being treated with passivation solution were continuously sprayed, and the time (h) consumed for corrosion to appear on the sample surface was observed and recorded.

[0061] High-temperature oxidation resistance test: The copper workpieces of each embodiment and comparative example after being treated with passivation solution were placed in a forced-air oven at 200°C and heated for 2 hours. After being taken out and cooled to room temperature, the color change was observed and compared with that before treatment. The ΔE value was measured with a colorimeter to evaluate the degree of color change.

[0062] Film adhesion test: Refer to the relevant standards in GB / T 9286-2021, use a cross-cutting tool to draw 1mm×1mm squares on the surface of each sample, apply 3M tape and quickly peel it off, observe the film peeling in the square area, and evaluate the adhesion level (0 is the best, 5 is the worst).

[0063] The test data is shown in Table 1.

[0064] Table 1 Results of each performance test The salt spray resistance test results show that the salt spray resistance time of the samples prepared in Examples 1 to 4 is much longer than that of Comparative Examples 1 to 5, especially the sample prepared in Example 1, which exhibits the best salt spray resistance. This indicates that the amino-modified boron nitride nanosheets, isohydroxamic acid-functionalized silsesquioxane hybrid film-forming corrosion inhibitor, benzotriazole, and the repair agent synergistically enhance the salt spray resistance. A comparison of the test results of Example 1 and Comparative Example 2 (without the addition of isohydroxamic acid-functionalized silsesquioxane hybrid film-forming corrosion inhibitor) shows that the strong chelating effect of the isohydroxamic acid groups is key to constructing a dense anti-corrosion film. A comparison of the test results of Example 1 and Comparative Example 5 (without the addition of the repair agent) shows that the presence of the repair agent can effectively extend the long-term anti-corrosion capability of the film and prevent the spread of localized corrosion. The high-temperature oxidation resistance test results show that the samples prepared in each embodiment exhibit better high-temperature oxidation resistance than those in the comparative examples. This indicates that the cage-like structure of the isohydroxamic acid-functionalized silsesquioxane hybrid film-forming corrosion inhibitor provides high-temperature structural stability, while the high thermal conductivity of the aminated boron nitride nanosheets effectively disperses the thermal stress of the film. The film adhesion test results show that the samples prepared in each embodiment exhibit superior adhesion performance, indicating that the passivating agents prepared in each embodiment have strong adhesion to the copper substrate surface.

[0065] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0066] Although embodiments of this application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a chromium-free passivating agent resistant to salt spray and high temperature for copper parts, characterized in that, Includes the following steps: S100, a premixed solution is obtained by mixing raw materials including aminated boron nitride nanosheets and silane coupling agents; S200. Add raw materials including isohydroxamic acid-functionalized silsesquioxane hybrid film-forming corrosion inhibitor and triazole derivative to the premixed solution and mix to obtain a mixed solution; S300. Add raw materials including a repair agent, a nonionic surfactant, and a pH adjuster to the mixture to prepare the passivating agent.

2. The preparation method of a salt spray resistant and high temperature resistant chromium-free passivating agent for copper parts according to claim 1, characterized in that, The preparation method of the isohydroxamic acid-functionalized silsesquioxane hybrid film-forming corrosion inhibitor is as follows: Under a nitrogen atmosphere, aminopropyl heptaisobutyl cage-like polysilsesquioxane is added to anhydrous tetrahydrofuran. After mixing evenly, it is placed in an ice-water bath and cooled to 0-5°C. Triethylamine is added to it while stirring, and then a mixed solution of isobutyryl chloride and anhydrous tetrahydrofuran is added dropwise. After the dropwise addition is completed, the temperature is raised to room temperature and the reaction is continued to be stirred for 12-16 hours to obtain a crude product. After purification, a white solid is obtained. After mixing with hydroxylamine methanol suspension, the temperature is raised to 60-65°C and refluxed for 6-8 hours. After secondary purification, the isohydroxamic acid-functionalized silsesquioxane hybrid film-forming corrosion inhibitor is obtained.

3. The method for preparing a salt spray resistant and high-temperature resistant chromium-free passivating agent for copper parts according to claim 2, characterized in that, The preparation method of the hydroxylamine methanol suspension is as follows: add hydroxylamine hydrochloride to methanol and stir until dissolved, place it in an ice-water bath, and add a methanol solution containing sodium hydroxide dropwise. After the addition is completed, the hydroxylamine methanol suspension is obtained.

4. The method for preparing a salt spray resistant and high-temperature resistant chromium-free passivating agent for copper parts according to claim 1, characterized in that, The triazole derivative is one or more of benzotriazole, methylbenzotriazole, and carboxybenzotriazole.

5. The method for preparing a salt spray resistant and high-temperature resistant chromium-free passivating agent for copper parts according to claim 1, characterized in that, The preparation method of the repair agent is as follows: Mg(NO3)2·6H2O and Al(NO3)3·9H2O are added to deionized water and stirred until dissolved. Under nitrogen atmosphere and stirring, sodium hydroxide solution containing Na2MoO4 is added to the solution, and the pH is controlled at 10±0.

2. After the addition is complete, the solution is crystallized at 60-70℃ for 24 hours. After centrifugation, washing and drying, a white powder is obtained, which is the repair agent.

6. The method for preparing a salt spray resistant and high-temperature resistant chromium-free passivating agent for copper parts according to claim 1, characterized in that, The nonionic surfactant is one or more of alkylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, and polyether-modified siloxane.

7. The method for preparing a salt spray resistant and high-temperature resistant chromium-free passivating agent for copper parts according to claim 1, characterized in that, The silane coupling agent is an aminosilane coupling agent or an epoxysilane coupling agent.

8. A chromium-free passivating agent for copper parts, characterized in that, It is prepared by the method described in any one of claims 1-7 for a chromium-free passivating agent for copper parts that is resistant to salt spray and high temperature.

9. The application of the salt spray resistant and high temperature resistant chromium-free passivating agent for copper parts according to claim 8 in the treatment of copper workpieces, characterized in that, The application includes the following steps: A1. The copper workpiece is degreased, washed with water, acid-washed and activated, and then washed a second time to obtain a clean workpiece. A2. Immerse the cleaned workpiece in the passivating agent and treat it at 40-50℃ for 6-10 minutes; A3. Remove the workpiece, wash it with water, and dry it at 90-120℃ for 20-30 minutes.

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