Preparation method of metal surface protective film

Abstract

The invention relates to the technical field of plating of metal materials, and discloses a metal surface protective film preparation method which comprises the steps that S1, raw materials are prepared, specifically, chromium, nickel and aluminum are prepared and can form a protective film, the corrosion resistance of metal is remarkably improved, meanwhile, copper is added, the corrosion resistance is improved by changing the electrode potential of the copper, and the corrosion resistance is improved; a graphene protective agent and hexagonal boron nitride are added, the graphene protective agent and the hexagonal boron nitride have good permeability resistance, oxalic acid and chromic acid solutions are prepared and used for conducting anodic oxidation on aluminum, micropores and defects of a film layer are filled with a sealing agent, the compactness and corrosion resistance of the film layer are improved, and the corrosion resistance of the film layer is improved. Oxidation of the protective film solution has a good protection effect on some metal materials with poor corrosion resistance, the situation that surface protective films of the metal materials are abraded after the metal materials are used for a long time, and consequently the corrosion resistance of the metal materials becomes poor is avoided, and practical benefits are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of plating of metal materials, in particular to a method for preparing a metal surface protective film. Background Art

[0002] Metals and alloys such as zinc, copper, aluminum, and steel are widely used in many fields, but due to their active chemical properties, they are prone to corrosion during use. In order to effectively inhibit the corrosion of these metals and extend their service life, they usually need to undergo certain surface treatments, such as chemical conversion and anodizing, which are commonly used metal surface treatment methods.

[0003] A protective film can be formed on the metal surface to provide protection for the metal substrate and can also effectively improve the adhesion between the coating and the alloy surface. However, in applications with harsh environments, a large amount of rainwater and dust will be deposited on the metal surface and it is not easy to clean and remove it in time. Rainwater mixed with dust will become a highly corrosive medium that corrodes and damages the metal and cause major accidents.

[0004] In the prior art, the publication (announcement) number is CN101440510A. Although the fatty acid salt super-hydrophobic surface is used for metal corrosion protection and self-cleaning, the metal material will wear out during use. Long-term use and severe wear will affect the protectiveness of the metal material. Therefore, there is an urgent need for a method for preparing a metal surface protective film with better texture. Summary of the invention

[0005] 1. Technical issues to be resolved

[0006] In view of the deficiencies of the prior art, the present invention provides a method for preparing a metal surface protective film, which solves the problem of poor protective performance of the protective film in the prior art.

[0007] (II) Technical solution

[0008] To achieve the above-mentioned purpose, the present invention provides the following technical scheme: a method for preparing a metal surface protective film, which is prepared according to the following weight ratio: chromium, nickel and aluminum account for 5-15 parts, 10-35 parts and 35-50 parts respectively, copper accounts for 15-30 parts, graphene protective agent accounts for 3-9 parts, hexagonal boron nitride accounts for 12-25 parts, oxalic acid solution accounts for 5 parts, and hydrochloric acid solution accounts for 4 parts.

[0009] A method for preparing a metal surface protective film comprises the following steps:

[0010] S1: raw material preparation: preparing chromium, nickel, aluminum and copper, preparing graphene protective agent and hexagonal boron nitride, preparing oxalic acid and chromic acid solution, oxalic acid and chromic acid solution are used for anodizing aluminum, metal materials, metal materials are the original parts for preparing protective film;

[0011] Prepare 5 parts of alkaline solution and 5 parts of acidic solution, the pH value of alkaline solution is 7.5, the pH value of acidic solution is 2.5, prepare sealing agent and distilled water, prepare lead plate;

[0012] S2: Pretreatment of metal material surface: First, clean the surface of the metal material to be protected to ensure that the surface of the metal material is clean;

[0013] S3: Mixing: The chromium in S1 is put into 1 part of hydrochloric acid solution for mixing reaction, the nickel is put into 1 part of hydrochloric acid solution for mixing reaction and the aluminum is put into 1 part of hydrochloric acid solution for mixing reaction to obtain a chromium metal salt solution, a nickel metal salt solution and an aluminum metal salt solution. Sodium hypophosphite needs to be added to the chromium metal salt solution, the nickel metal salt solution and the aluminum metal salt solution. The chromium metal salt solution, the nickel metal salt solution and the aluminum metal salt solution mixed with sodium hypophosphite are mixed by a stirring device. When the chromium metal salt solution, the nickel metal salt solution and the aluminum metal salt solution mixed with sodium hypophosphite are mixed, copper is added and stirred for 30 minutes to obtain a protective film solution.

[0014] S4: Electrolytic oxidation: Pour 5 parts of oxalic acid solution into the protective film solution described in S3 and mix and stir, place the metal material in the protective film solution mixed with oxalic acid solution, use the treated metal material as the anode, and then put the lead plate in as the cathode to form an oxide film by electrolysis;

[0015] S5: Post-oxidation treatment of oxide film: prepare sealing agent and distilled water. The sealing agent is composed of organic corrosion inhibitor, inorganic nanomaterial, water-soluble high molecular polymer and water. The sealing agent and distilled water are mixed in a ratio of 1:5, and the treated metal material is placed in it to obtain a sealed metal material;

[0016] S6: Protective film preparation and molding: Grind the metal material sealed in S5.

[0017] Preferably, in S2, the treated metal material is wiped, and then 5 parts of an acidic solution are used to remove alkaline residues and impurities on the metal surface, and then the chemical residual components on the metal surface are removed by water washing, and the treated metal material is set aside.

[0018] Preferably, the stirring time in S3 is 20-30 minutes, and 15-30 parts of copper are added when the chromium metal salt solution, nickel metal salt solution and aluminum metal salt solution mixed with sodium hypophosphite are mixed. At the same time, 12-25 parts of hexagonal boron nitride are added during the stirring process, and then after standing for 10 minutes, 3-9 parts of graphene protective agent are added. After mixing, a protective film solution mixed with graphene protective agent is obtained, which is taken out and placed in a container for standby use.

[0019] Preferably, at the anode in the S4 process, the metal material loses electrons to form cations, which then combine with oxygen in water to form an oxide film.

[0020] Preferably, the pH value of the sealant mixed in S5 is between 6.5 and 7.5, and the metal material with the oxide film is placed in the solution and allowed to stand for 2 to 5 minutes to seal the metal surface.

[0021] Preferably, the grinding time in S6 is 1-3 minutes, and the grinding is performed with a grinding wheel.

[0022] (III) Beneficial effects

[0023] Compared with the prior art, the present invention provides a method for preparing a metal surface protective film, which has the following beneficial effects:

[0024] 1. The method for preparing a metal surface protective film fills the micropores and defects of the film layer with a sealing agent to improve the density and corrosion resistance of the film layer. The oxidation of the protective film solution has a good protective effect on some metal materials with poor corrosion resistance, thereby avoiding the wear of the surface protective film of these metal materials under long-term use, which leads to the deterioration of the corrosion resistance of the metal materials. The method has practical benefits. At the same time, the method for preparing a metal surface protective film has the characteristics of low cost and green environmental protection, and the process is simple, the operation is convenient, and it is easy to large-scale industrial production.

[0025] 2. The method for preparing the metal surface protective film is to oxidize the protective film solution. When used for some metal materials that are not often worn, a thin layer of the protective film solution is set to reflect the original texture of the metal material. DETAILED DESCRIPTION

[0026] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0027] A method for preparing a metal surface protective film: the following is prepared in proportions by weight: chromium, nickel and aluminum account for 5-15 parts, 10-35 parts and 35-50 parts respectively, copper accounts for 15-30 parts, graphene protective agent accounts for 3-9 parts, hexagonal boron nitride accounts for 12-25 parts, oxalic acid solution accounts for 5 parts, and hydrochloric acid solution accounts for 4 parts.

[0028] Embodiment 1:

[0029] A method for preparing a metal surface protective film comprises the following steps:

[0030] S1: Raw material preparation: prepare chromium, nickel and aluminum, which can form a protective film and significantly improve the corrosion resistance of the metal. At the same time, copper is added to improve the corrosion resistance by changing the electrode potential of copper. Graphene protective agent and hexagonal boron nitride are added. Graphene protective agent and hexagonal boron nitride have good anti-permeability. Prepare oxalic acid and chromic acid solutions. Oxalic acid and chromic acid solutions are used for anodizing aluminum. Prepare hydrochloric acid solution with a concentration of 12 mol / L. Reducing agent, including sodium hypophosphite. Prepare 5 parts of alkaline solution and 5 parts of acidic solution. The pH value of the alkaline solution is 7.5 and the pH value of the acidic solution is 2.5. Prepare sealing agent and distilled water. Prepare lead plate;

[0031] Chromium, nickel and aluminum account for 15 parts, 35 parts and 50 parts respectively, copper accounts for 30 parts, graphene protective agent accounts for 9 parts, hexagonal boron nitride accounts for 25 parts, oxalic acid solution accounts for 5 parts, and hydrochloric acid solution accounts for 4 parts.

[0032] S2: Surface pretreatment of metal materials: First, clean the surface of the metal material that needs to be protected to remove grease, dirt and other impurities, use 5 parts of alkaline solution to remove the natural oxide film and impurities on the metal surface, wipe the treated metal material, and then use 5 parts of acidic solution to remove the alkaline residues and impurities on the metal surface, and then remove the chemical residual components on the metal surface by water washing, and set the treated metal material aside.

[0033] S3: Mixing: Put the chromium in S1 into 1 part of hydrochloric acid solution for mixing reaction, put the nickel into 1 part of hydrochloric acid solution for mixing reaction and put the aluminum into 1 part of hydrochloric acid solution for mixing reaction to obtain chromium metal salt solution, nickel metal salt solution and aluminum metal salt solution. Sodium hypophosphite needs to be added to the chromium metal salt solution, nickel metal salt solution and aluminum metal salt solution. The chromium metal salt solution, nickel metal salt solution and aluminum metal salt solution mixed with sodium hypophosphite are mixed by a stirring equipment for 20-30 minutes. When the chromium metal salt solution, nickel metal salt solution and aluminum metal salt solution mixed with sodium hypophosphite are mixed, 30 parts of copper are added, and 25 parts of hexagonal boron nitride are added during the stirring process. After standing for 10 minutes, 9 parts of graphene protective agent are added to obtain a protective film solution mixed with graphene protective agent, which is taken out and placed in a container for standby use.

[0034] S4: Electrolytic oxidation: Pour 5 parts of oxalic acid solution into the protective film solution mixed with graphene protective agent in S3 and mix and stir. Place the metal material in the protective film solution mixed with oxalic acid solution. The treated metal material is used as the anode. Then put the lead plate in as the cathode and perform electrolysis to form an oxide film. At the anode in this process, the metal material loses electrons to form cations, which are then combined with oxygen in the water to form an oxide film. The oxide film covers the surface of the metal material to obtain a metal material with an oxide film. Since chromium and nickel are mixed in the solution, the oxide film formed is very hard and can protect the metal from further corrosion. It is also wear-resistant.

[0035] S5: Post-oxidation treatment of oxide film: prepare sealant and distilled water. The sealant is composed of organic corrosion inhibitor, inorganic nanomaterial, water-soluble polymer and water. The sealant and distilled water are mixed in a ratio of 1:5 to make the pH value between 6.5-7.5. Place the metal material with oxide film in the solution and let it stand for 2-5 minutes. Place the treated metal material in it to obtain a sealed metal material.

[0036] S6: Preparation and molding of protective film: Grind the metal material sealed in S5 to make the surface of the sealed metal material smooth and tidy. The grinding time is 1-3 minutes, and then it can be molded.

[0037] In the above steps, the micropores and defects of the film layer are filled with a sealing agent to improve the density and corrosion resistance of the film layer. The oxidation of the protective film solution has a good protective effect on some metal materials with poor corrosion resistance, thereby avoiding the wear of the surface protective film of these metal materials under long-term use, which leads to the deterioration of the corrosion resistance of the metal materials. It has practical benefits. At the same time, the method for preparing the metal surface protective film is low in cost and green and environmentally friendly, and has a simple process, convenient operation, and is easy to large-scale industrial production.

[0038] Embodiment 2:

[0039] A method for preparing a metal surface protective film comprises the following steps:

[0040] S1: Raw material preparation: prepare chromium, nickel and aluminum, which can form a protective film and significantly improve the corrosion resistance of the metal. At the same time, copper is added to improve the corrosion resistance by changing the electrode potential of copper. Graphene protective agent and hexagonal boron nitride are added. Graphene protective agent and hexagonal boron nitride have good anti-permeability. Oxalic acid and chromic acid solutions are prepared. Oxalic acid and chromic acid solutions are used for anodizing aluminum. Hydrochloric acid solution is prepared. The concentration of hydrochloric acid solution is 12 mol / L. Reducing agent, including sodium hypophosphite;

[0041] Chromium, nickel and aluminum account for 5 parts, 10 parts and 35 parts respectively, copper accounts for 15 parts, graphene protective agent accounts for 3 parts, hexagonal boron nitride accounts for 12 parts, oxalic acid solution accounts for 5 parts, and hydrochloric acid solution accounts for 4 parts.

[0042] S2: Surface pretreatment of metal materials: First, clean the surface of the metal material that needs to be protected to remove grease, dirt and other impurities to ensure that the surface of the metal material is clean. Use 5 parts of alkaline solution to remove the natural oxide film and impurities on the metal surface. Wipe the treated metal material, then use 5 parts of acidic solution to remove the alkaline residues and impurities on the metal surface. Then remove the chemical residual components on the metal surface by washing with water, and set the treated metal material aside.

[0043] S3: Mixing: Put the chromium in S1 into 1 part of hydrochloric acid solution for mixing reaction, put the nickel into 1 part of hydrochloric acid solution for mixing reaction and put the aluminum into 1 part of hydrochloric acid solution for mixing reaction to obtain chromium metal salt solution, nickel metal salt solution and aluminum metal salt solution. Sodium hypophosphite needs to be added to the chromium metal salt solution, nickel metal salt solution and aluminum metal salt solution. The chromium metal salt solution, nickel metal salt solution and aluminum metal salt solution mixed with sodium hypophosphite are mixed by a stirring equipment for 20-30 minutes. When the chromium metal salt solution, nickel metal salt solution and aluminum metal salt solution mixed with sodium hypophosphite are mixed, 15 parts of copper are added, and 12 parts of hexagonal boron nitride are added during the stirring process. After standing for 10 minutes, 3 parts of graphene protective agent are added. After mixing, a protective film solution mixed with graphene protective agent is obtained, which is taken out and placed in a container for standby use.

[0044] S4: Electrolytic oxidation: Pour 5 parts of oxalic acid solution into the protective film solution mixed with graphene protective agent in S3 and mix and stir. Place the metal material in the solution, use the treated metal material as the cathode, and then put the graphite plate in as the anode for electrolysis to form an oxide film. In this process, the cathode combines with oxygen in the water to form an oxide. Since chromium and nickel are mixed in the solution, the oxide film formed is very hard and can protect the metal from further corrosion. It is also wear-resistant.

[0045] S5: Post-oxidation treatment of oxide film: prepare sealant and distilled water. The sealant is composed of organic corrosion inhibitor, inorganic nanomaterials, water-soluble high molecular polymer and water. The sealant and distilled water are mixed in a ratio of 1:5 so that the pH value is between 6.5-7.5. Place the metal material with oxide film in the solution and let it stand for 2-5 minutes to seal the metal surface.

[0046] S6: Preparation and molding of protective film: Grind the metal material sealed in S5 to make the surface of the sealed metal material smooth and tidy. The grinding time is 1-3 minutes, and then it can be molded. After the oxide film is formed, it can be dyed to make the metal surface present different colors.

[0047] In the above steps, when the protective film solution oxidation is used for some metal materials that are not often worn, a thin layer of the protective film solution is set to reflect the original texture of the metal material. At the same time, step S6 is added to ensure the aesthetics of the metal material.

[0048] Embodiment three:

[0049] A method for preparing a metal surface protective film comprises the following steps:

[0050] S1: Raw material preparation: prepare chromium, nickel and aluminum, which can form a protective film and significantly improve the corrosion resistance of the metal. At the same time, copper is added to improve the corrosion resistance by changing the electrode potential of copper. Graphene protective agent and hexagonal boron nitride are added. Graphene protective agent and hexagonal boron nitride have good anti-permeability. Oxalic acid and chromic acid solutions are prepared. Oxalic acid and chromic acid solutions are used for anodizing aluminum. Hydrochloric acid solution is prepared. The concentration of hydrochloric acid solution is 12 mol / L. Reducing agent, including sodium hypophosphite;

[0051] Chromium, nickel and aluminum account for 8 parts, 12 parts and 35 parts respectively, copper accounts for 20 parts, graphene protective agent accounts for 6 parts, hexagonal boron nitride accounts for 20 parts, oxalic acid solution accounts for 5 parts and hydrochloric acid solution accounts for 4 parts.

[0052] S2: Surface pretreatment of metal materials: First, clean the surface of the metal material that needs to be protected to remove grease, dirt and other impurities to ensure that the surface of the metal material is clean. Use 5 parts of alkaline solution to remove the natural oxide film and impurities on the metal surface. Wipe the treated metal material, then use 5 parts of acidic solution to remove the alkaline residues and impurities on the metal surface. Then remove the chemical residual components on the metal surface by washing with water, and set the treated metal material aside.

[0053] S3: Mixing: Put the chromium in S1 into 1 part of hydrochloric acid solution for mixing reaction, put the nickel into 1 part of hydrochloric acid solution for mixing reaction and put the aluminum into 1 part of hydrochloric acid solution for mixing reaction to obtain chromium metal salt solution, nickel metal salt solution and aluminum metal salt solution. Sodium hypophosphite needs to be added to the chromium metal salt solution, nickel metal salt solution and aluminum metal salt solution. The chromium metal salt solution, nickel metal salt solution and aluminum metal salt solution mixed with sodium hypophosphite are mixed by a stirring equipment for 20-30 minutes. When the chromium metal salt solution, nickel metal salt solution and aluminum metal salt solution mixed with sodium hypophosphite are mixed, 20 parts of copper are added, and 20 parts of hexagonal boron nitride are added during the stirring process. After standing for 10 minutes, 6 parts of graphene protective agent are added. After mixing, a protective film solution mixed with graphene protective agent is obtained, which is taken out and placed in a container for standby use.

[0054] S4: Electrolytic oxidation: Pour 5 parts of oxalic acid solution into the protective film solution mixed with graphene protective agent in S3 and mix and stir. Place the metal material in the solution, use the treated metal material as the anode, and then put the lead plate in as the cathode for electrolysis to form an oxide film. At the anode in this process, the metal material loses electrons to form cations, which are then combined with oxygen in the water to form an oxide film. Since chromium and nickel are mixed in the solution, the oxide film formed is very hard and can protect the metal from further corrosion. It is also wear-resistant.

[0055] S5: Post-oxidation treatment of oxide film: prepare sealant and distilled water. The sealant is composed of organic corrosion inhibitor, inorganic nanomaterials, water-soluble high molecular polymer and water. The sealant and distilled water are mixed in a ratio of 1:5 so that the pH value is between 6.5-7.5. Place the metal material with oxide film in the solution and let it stand for 2-5 minutes to seal the metal surface.

[0056] S6: Preparation and molding of protective film: Grind the metal material sealed in S5 to make the surface of the sealed metal material smooth and tidy. The grinding time is 1-3 minutes, and then it can be molded.

[0057] Embodiment 4:

[0058] A method for preparing a metal surface protective film comprises the following steps:

[0059] S1: Raw material preparation: prepare chromium, nickel and aluminum, which can form a protective film and significantly improve the corrosion resistance of the metal. At the same time, copper is added to improve the corrosion resistance by changing the electrode potential of copper. Graphene protective agent and hexagonal boron nitride are added. Graphene protective agent and hexagonal boron nitride have good anti-permeability. Oxalic acid and chromic acid solutions are prepared. Oxalic acid and chromic acid solutions are used for anodizing aluminum. Hydrochloric acid solution is prepared. The concentration of hydrochloric acid solution is 12 mol / L. Reducing agent, including sodium hypophosphite;

[0060] Chromium, nickel and aluminum account for 13 parts, 20 parts and 40 parts respectively, copper accounts for 25 parts, graphene protective agent accounts for 7 parts, hexagonal boron nitride accounts for 18 parts, oxalic acid solution accounts for 5 parts, and hydrochloric acid solution accounts for 4 parts.

[0061] S2: Surface pretreatment of metal materials: First, clean the surface of the metal material that needs to be protected to remove grease, dirt and other impurities to ensure that the surface of the metal material is clean. Use 5 parts of alkaline solution to remove the natural oxide film and impurities on the metal surface. Wipe the treated metal material, then use 5 parts of acidic solution to remove the alkaline residues and impurities on the metal surface. Then remove the chemical residual components on the metal surface by washing with water, and set the treated metal material aside.

[0062] S3: Mixing: Put the chromium in S1 into 1 part of hydrochloric acid solution for mixing reaction, put the nickel into 1 part of hydrochloric acid solution for mixing reaction and put the aluminum into 1 part of hydrochloric acid solution for mixing reaction to obtain chromium metal salt solution, nickel metal salt solution and aluminum metal salt solution. Sodium hypophosphite needs to be added to the chromium metal salt solution, nickel metal salt solution and aluminum metal salt solution. The chromium metal salt solution, nickel metal salt solution and aluminum metal salt solution mixed with sodium hypophosphite are mixed by a stirring equipment for 20-30 minutes. When the chromium metal salt solution, nickel metal salt solution and aluminum metal salt solution mixed with sodium hypophosphite are mixed, 25 parts of copper are added, and 12 parts of hexagonal boron nitride are added during the stirring process. After standing for 10 minutes, 3 parts of graphene protective agent are added. After mixing, a protective film solution mixed with graphene protective agent is obtained, which is taken out and placed in a container for standby use.

[0063] S4: Electrolytic oxidation: Pour 5 parts of oxalic acid solution into the protective film solution mixed with graphene protective agent in S3 and mix and stir. Place the metal material in the solution, use the treated metal material as the anode, and then put the lead plate in as the cathode for electrolysis to form an oxide film. At the anode in this process, the metal material loses electrons to form cations, which are then combined with oxygen in the water to form an oxide film. Since chromium and nickel are mixed in the solution, the oxide film formed is very hard and can protect the metal from further corrosion. It is also wear-resistant.

[0064] S5: Post-oxidation treatment of oxide film: prepare sealant and distilled water. The sealant is composed of organic corrosion inhibitor, inorganic nanomaterials, water-soluble high molecular polymer and water. The sealant and distilled water are mixed in a ratio of 1:5 so that the pH value is between 6.5-7.5. Place the metal material with oxide film in the solution and let it stand for 2-5 minutes to seal the metal surface.

[0065] S6: Preparation and molding of protective film: Grind the metal material sealed in S5 to make the surface of the sealed metal material smooth and tidy. The grinding time is 1-3 minutes, and then it can be molded.

[0066] Embodiment five:

[0067] A method for preparing a metal surface protective film comprises the following steps:

[0068] S1: Raw material preparation: prepare chromium, nickel and aluminum, which can form a protective film and significantly improve the corrosion resistance of the metal. At the same time, copper is added to improve the corrosion resistance by changing the electrode potential of copper. Graphene protective agent and hexagonal boron nitride are added. Graphene protective agent and hexagonal boron nitride have good anti-permeability. Oxalic acid and chromic acid solutions are prepared. Oxalic acid and chromic acid solutions are used for anodizing aluminum. Hydrochloric acid solution is prepared. The concentration of hydrochloric acid solution is 12 mol / L. Reducing agent, including sodium hypophosphite;

[0069] Chromium, nickel and aluminum account for 5 parts, 10 parts and 45 parts respectively, copper accounts for 20 parts, graphene protective agent accounts for 3 parts, hexagonal boron nitride accounts for 22 parts, oxalic acid solution accounts for 5 parts, and hydrochloric acid solution accounts for 4 parts.

[0070] S2: Surface pretreatment of metal materials: First, clean the surface of the metal material that needs to be protected to remove grease, dirt and other impurities to ensure that the surface of the metal material is clean. Use 5 parts of alkaline solution to remove the natural oxide film and impurities on the metal surface. Wipe the treated metal material, then use 5 parts of acidic solution to remove the alkaline residues and impurities on the metal surface. Then remove the chemical residual components on the metal surface by washing with water, and set the treated metal material aside.

[0071] S3: Mixing: Put the chromium in S1 into 1 part of hydrochloric acid solution for mixing reaction, put the nickel into 1 part of hydrochloric acid solution for mixing reaction and put the aluminum into 1 part of hydrochloric acid solution for mixing reaction to obtain chromium metal salt solution, nickel metal salt solution and aluminum metal salt solution. Sodium hypophosphite needs to be added to the chromium metal salt solution, nickel metal salt solution and aluminum metal salt solution. The chromium metal salt solution, nickel metal salt solution and aluminum metal salt solution mixed with sodium hypophosphite are mixed by a stirring equipment for 20-30 minutes. When the chromium metal salt solution, nickel metal salt solution and aluminum metal salt solution mixed with sodium hypophosphite are mixed, 20 parts of copper are added, and 22 parts of hexagonal boron nitride are added during the stirring process. After standing for 10 minutes, 3 parts of graphene protective agent are added. After mixing, a protective film solution mixed with graphene protective agent is obtained, which is taken out and placed in a container for standby use.

[0072] S4: Electrolytic oxidation: Pour 5 parts of oxalic acid solution into the protective film solution mixed with graphene protective agent in S3 and mix and stir. Place the metal material in the solution, use the treated metal material as the anode, and then put the lead plate in as the cathode for electrolysis to form an oxide film. At the anode in this process, the metal material loses electrons to form cations, which are then combined with oxygen in the water to form an oxide film. Since chromium and nickel are mixed in the solution, the oxide film formed is very hard and can protect the metal from further corrosion. It is also wear-resistant.

[0073] S5: Post-oxidation treatment of oxide film: prepare sealant and distilled water. The sealant is composed of organic corrosion inhibitor, inorganic nanomaterials, water-soluble high molecular polymer and water. The sealant and distilled water are mixed in a ratio of 1:5 so that the pH value is between 6.5-7.5. Place the metal material with oxide film in the solution and let it stand for 2-5 minutes to seal the metal surface.

[0074] S6: Preparation and molding of protective film: Grind the metal material sealed in S5 to make the surface of the sealed metal material smooth and tidy. The grinding time is 1-3 minutes, and then it can be molded.

[0075] The following table shows the raw material ratios used in the actual experiment of a metal surface protective film:

[0076]

[0077]

[0078] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a metal surface protective film, characterized in that: The following is prepared according to the weight ratio: chromium, nickel and aluminum are 5-15 parts, 10-35 parts and 35-50 parts respectively, copper is 15-30 parts, graphene protective agent is 3-9 parts, hexagonal boron nitride is 12-25 parts, oxalic acid solution is 5 parts, and hydrochloric acid solution is 4 parts.

2. A method for preparing a metal surface protective film according to claim 1, characterized in that: The following steps are involved: S1: raw material preparation: preparing chromium, nickel, aluminum and copper, preparing graphene protective agent and hexagonal boron nitride, preparing oxalic acid and chromic acid solutions, metal materials, preparing hydrochloric acid solution, the concentration of the hydrochloric acid solution is 12 mol / L, and reducing agent, the reducing agent includes sodium hypophosphite; Prepare 5 parts of alkaline solution and 5 parts of acidic solution, the pH value of alkaline solution is 7.5, the pH value of acidic solution is 2.5, prepare sealing agent and distilled water, prepare lead plate; S2: Pretreatment of metal material surface: Clean the surface of the metal material that needs to be protected to ensure that the surface of the metal material is clean; S3: Mixing: The chromium in S1 is put into 1 part of hydrochloric acid solution for mixing reaction, the nickel is put into 1 part of hydrochloric acid solution for mixing reaction and the aluminum is put into 1 part of hydrochloric acid solution for mixing reaction to obtain a chromium metal salt solution, a nickel metal salt solution and an aluminum metal salt solution. Sodium hypophosphite needs to be added to the chromium metal salt solution, the nickel metal salt solution and the aluminum metal salt solution. The chromium metal salt solution, the nickel metal salt solution and the aluminum metal salt solution mixed with sodium hypophosphite are mixed by a stirring device. When the chromium metal salt solution, the nickel metal salt solution and the aluminum metal salt solution mixed with sodium hypophosphite are mixed, copper is added and stirred for 30 minutes to obtain a protective film solution. S4: Electrolytic oxidation: Pour 5 parts of oxalic acid solution into the protective film solution described in S3 and mix and stir, place the metal material in the protective film solution mixed with oxalic acid solution, use the treated metal material as the anode, and then put the lead plate in as the cathode to form an oxide film by electrolysis; S5: Post-oxidation treatment of oxide film: prepare sealing agent and distilled water. The sealing agent is composed of organic corrosion inhibitor, inorganic nanomaterial, water-soluble high molecular polymer and water. The sealing agent and distilled water are mixed in a ratio of 1:5, and the treated metal material is placed in it to obtain a sealed metal material; S6: Protective film preparation and molding: Grind the metal material sealed in S5.

3. A method for preparing a metal surface protective film according to claim 2, characterized in that: In S2, the treated metal material is wiped, and then 5 parts of an acidic solution are used to remove alkaline residues and impurities on the metal surface, and then chemical residual components on the metal surface are removed by water washing, and the treated metal material is set aside.

4. The method for preparing a metal surface protective film according to claim 2, characterized in that: The stirring time in S3 is 20-30 minutes. When the chromium metal salt solution, nickel metal salt solution and aluminum metal salt solution mixed with sodium hypophosphite are mixed, 15-30 parts of copper are added, and 12-25 parts of hexagonal boron nitride are added during the stirring process. Then, after standing for 10 minutes, 3-9 parts of graphene protective agent are added. After mixing, a protective film solution mixed with graphene protective agent is obtained, which is taken out and placed in a container for standby use.

5. The method for preparing a metal surface protective film according to claim 2, characterized in that: At the anode in the S4 process, the metal material loses electrons to form cations, which then combine with oxygen in water to form an oxide film.

6. The method for preparing a metal surface protective film according to claim 2, characterized in that: The pH value of the sealant mixed in S5 is between 6.5 and 7.

5. The metal material with the oxide film is placed in the solution and allowed to stand for 2 to 5 minutes to seal the metal surface.

7. The method for preparing a metal surface protective film according to claim 2, characterized in that: The grinding time in S6 is 1-3 minutes, and the grinding is performed using a grinding wheel.

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