Cage type silsesquioxane treating fluid and method for preparing conversion film on metal surface

Abstract

The invention belongs to the technical field of metal surface pretreatment, and relates to a polyhedral oligomeric silsesquioxane treating fluid and a method for preparing a conversion film on a metal surface. The treatment liquid for treating the surface of the copper alloy contains octamercaptopropyl silsesquioxane with the mass concentration of 0.05-5%. The treating fluid for treating the surface of the steel alloy contains octa-aminopropyl silsesquioxane with the mass concentration of 0.05-5%. Meanwhile, the pH value of the treating fluid is adjusted to be acidic by adopting organic acid. The polyhedral oligomeric silsesquioxane treating fluid provided by the invention can form a conversion film layer on the surface of metal, so that the corrosion resistance of the metal can be improved, and the binding force of the film layer can be improved.

Description

Technical Field

[0001] The invention belongs to the technical field of metal surface pretreatment, and relates to a cage-type silsesquioxane treatment liquid and a method for preparing a conversion film on a metal surface. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance understanding of the overall background of the invention and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to those skilled in the art.

[0003] Inorganic passivation technologies for metal surfaces (such as phosphating and chromating) have long been widely used in the metal surface pretreatment industry due to their ability to provide excellent corrosion protection and outstanding adhesion to metal surfaces. However, the high toxicity and carcinogenicity of inorganic chromates and inorganic phosphating sludge seriously harm the ecological environment and affect people's health. In the past two decades, a large number of scientific researchers have turned their research to exploring organic self-assembled films on metal surfaces. However, new organic self-assembled films often face problems such as self-assembled film failure caused by organic-inorganic interface effects, thin self-assembled films, poor wear resistance, or difficulty in providing good adhesion.

[0004] And novel cage type silsesquioxane (POSS) has been applied to coating additives or modified coating fields as a kind of intramolecular organic-inorganic hybrid material, to improve the wear resistance of coating, strengthen aspects such as corrosion resistance.This cage type silsesquioxane has the silicon-oxygen-silicon three-dimensional network structure of peripheral organic chain structure and inner silicon dioxide-like silicon dioxide to form, has the advantages such as the high reactivity of organic material and the high hardness, hydrophobicity of inorganic material concurrently.But POSS material is still imperfect as metal surface pretreatment technology at present.Through the inventor's research discovery, only after metal surface is processed with POSS material, still have the problems such as poor metal corrosion and poor coating adhesion, thereby be difficult to replace phosphating, chromization etc. to the inorganic passivation technology of metal surface. Summary of the Invention

[0005] In order to address the deficiencies of the prior art, the present invention aims to provide a cage-type silsesquioxane treatment liquid and a method for preparing a conversion film on a metal surface. The cage-type silsesquioxane treatment liquid provided by the present invention can form a conversion film layer on the metal surface, which can not only improve the corrosion resistance of the metal, but also improve the bonding strength of the film layer.

[0006] In order to achieve the above object, the technical solution of the present invention is:

[0007] In a first aspect, a cage-type silsesquioxane treatment solution is provided for treating a copper alloy surface. The treatment solution contains octamercaptopropyl silsesquioxane (POSS-SH) at a mass concentration of 0.05 to 5%. The pH value of the treatment solution is adjusted to acidic using an organic acid.

[0008] The present invention adopts a cage-type silsesquioxane containing multiple sulfhydryl groups (-SH). Under acidic conditions, the strong adsorption capacity of the sulfhydryl groups on the copper surface and the adsorption of chloride ions by the cage structure make the chloride ions in the treatment solution affected by the negative charge of the membrane, causing changes in the double electric layer, preventing further adsorption of chloride ions in the treatment solution, and significantly improving its corrosion resistance. At the same time, POSS-SH, as an intramolecular organic-inorganic hybrid material, can provide the film layer with stronger wear resistance and adhesion. At the same time, the use of organic acid to adjust the pH is conducive to closing the active sites on the copper alloy surface through complexation, which is conducive to further improving the corrosion resistance.

[0009] Some embodiments also include a rare earth salt additive at a concentration of 1 to 10 g / L. Studies have shown that the addition of a rare earth salt can synergistically enhance the corrosion resistance of copper alloys with octamercaptopropylsilsesquioxane. This is primarily due to the rare earth metal ions being enriched in the film through coordination and forming rare earth metal oxides during the corrosion process, increasing the film's density and thus preventing further attack by corrosive species.

[0010] In a second aspect, a method for preparing a conversion film on a metal surface comprises pickling a copper alloy with a nitric acid solution, and then immersing the pickled copper alloy in the cage-type silsesquioxane treatment solution described in the first aspect of the present invention for film-forming treatment, so that a chemical conversion film is formed on the surface of the pickled copper alloy.

[0011] In a third aspect, a cage-type silsesquioxane treatment liquid is provided for treating the surface of a steel alloy. The treatment liquid contains octaaminopropyl silsesquioxane (POSS-NH2) at a mass concentration of 0.05 to 5%. The pH value of the treatment liquid is adjusted to acidic using an organic acid.

[0012] The present invention adopts a plurality of primary amino groups (-NH2) in a cage-type silsesquioxane. Under acidic conditions, the strong adsorption capacity of the primary amino group on the iron surface and the cage structure adsorption of chloride ions make the chloride ions in the treatment solution subject to the negative charge of the membrane, and the double electric layer changes, preventing the further adsorption of chloride ions in the treatment solution, thereby significantly improving its corrosion resistance. At the same time, POSS-NH2, as an intramolecular organic-inorganic hybrid material, can provide stronger wear resistance and adhesion for the film layer. At the same time, organic acid is used to adjust the pH, which is conducive to closing the active sites on the surface of the steel alloy by complexation, and is conducive to further improving the corrosion resistance.

[0013] In some embodiments, an additive having a mass concentration of 0.2 to 1.0% is also included, wherein the additive is tetraethyl orthosilicate and / or aminopropyl triethoxysilane. Studies have shown that when tetraethyl orthosilicate or aminopropyl triethoxysilane is further added (especially when tetraethyl orthosilicate or aminopropyl triethoxysilane is added at the same time), it can synergistically enhance the corrosion resistance of steel alloys with octaaminopropyl silsesquioxane. This synergistic effect is mainly reflected in the following: the silanol formed after the hydrolysis of tetraethyl orthosilicate is anchored on the steel surface through chemical adsorption, and further forms a silicon-oxygen network cross-linked structure with the hydrolyzed aminosilanol through dehydration condensation, and finally combines with octaaminopropyl silsesquioxane through hydrogen bonding to provide a chemical conversion film with multiple properties.

[0014] In a fourth aspect, a method for preparing a conversion film on a metal surface comprises pickling a steel alloy with a nitric acid solution, and then immersing the pickled steel alloy in the cage-type silsesquioxane treatment solution described in the third aspect of the present invention for film-forming treatment, so that a chemical conversion film is formed on the surface of the pickled steel alloy.

[0015] The steel alloy described in the present invention refers to steel or alloy steel.

[0016] The beneficial effects of the present invention are:

[0017] The present invention adopts different groups to modify POSS material for different metals. The affinity of sulfydryl group to copper is higher and the affinity of amino group to iron is higher, so that POSS material can form conversion film on metal surface self-assembly. At the same time, the organic-inorganic hybrid structure in POSS molecule can reduce the interface effect of organic self-assembled film on metal surface, thereby improving the bonding force of film layer. POSS material has higher hardness, improves the wear resistance of self-assembled film, and reduces the film layer failure problem caused by mechanical damage. The silicon-oxygen silicon and incidental carbon chain structure of POSS material naturally possess good hydrophobicity and have waterproof and dirt-proof effect. Compared with the conversion film formed by other self-assembly, the present invention prepares conversion film on metal surface and has better corrosion resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0019] Figure 1 The H-NMR spectrum of POSS-SH prepared in Example 1 of the present invention;

[0020] Figure 2 This is a graph showing the immersion impedance results of Examples 1-2 and Comparative Example 1 of the present invention;

[0021] Figure 3AFM mechanical property test results of Examples 1-2 and Comparative Example 2 of the present invention are shown;

[0022] Figure 4 The nanoindentation test results of Examples 1-2 and Comparative Example 2 of the present invention are shown;

[0023] Figure 5 The contact angle test results of Examples 1-2 and Comparative Example 1 of the present invention are shown below:

[0024] Figure 6 This is a graph showing the immersion impedance results of Examples 3-6 of the present invention and Comparative Example 3. DETAILED DESCRIPTION

[0025] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention belongs.

[0026] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0027] Since the existing technology still suffers from problems such as poor metal corrosion and poor coating adhesion after using only POSS materials to treat metal surfaces, the present invention proposes a cage-type silsesquioxane treatment liquid and a method for preparing a conversion film on a metal surface.

[0028] A typical embodiment of the present invention provides a cage-type silsesquioxane treatment solution for treating the surface of a copper alloy, wherein the treatment solution contains octamercaptopropyl silsesquioxane at a mass concentration of 0.05 to 5%; and an organic acid is used to adjust the pH value of the treatment solution to an acidic state.

[0029] The present invention utilizes the chemical adsorption and dehydration condensation of POSS-based cage-type organic-inorganic hybrid materials on the metal surface to improve the corrosion resistance of the metal and at the same time give the conversion film multiple additional functions, such as high wear resistance and high hydrophobicity. At the same time, since it weakens the interface effect of the organic self-assembled film on the inorganic metal interface, it also enhances the bonding force of the film layer.

[0030] The preparation method of octamercaptopropylsilsesquioxane is as follows: 3-mercaptopropyltrimethoxysilane is heated to 90-95° C. in a mixed solution of hydrochloric acid and methanol for reaction, and the octamercaptopropylsilsesquioxane is obtained after the reaction.

[0031] In some embodiments, the mass concentration of octamercaptopropylsilsesquioxane in the treatment solution is 0.05 to 1.0%, preferably 0.05 to 0.5%, and more preferably 0.1 to 0.5%.

[0032] In some embodiments, an additive is further included at a concentration of 1 to 10 g / L, wherein the additive is a rare earth salt. Specifically, the concentration of the additive in the treatment solution is 2 to 6 g / L, preferably 3 to 5 g / L. Specifically, the rare earth salt is a rare earth nitrate, preferably one of lanthanum nitrate, yttrium nitrate, neodymium nitrate, cerium nitrate, and zirconium nitrate. Nitrates have higher solubility and are conducive to a synergistic effect with octamercaptopropylsilsesquioxane on the copper alloy surface. Studies have shown that neodymium nitrate is more effective as an additive.

[0033] In some embodiments, the organic acid is acetic acid, which has less steric hindrance and better effect.

[0034] In some embodiments, the pH value of the treatment solution is adjusted to 4-6.

[0035] In some embodiments, the solvent of the treatment liquid is a mixture of tetrahydrofuran and water, specifically, the volume ratio of tetrahydrofuran to water is 1:0.9-1.1.

[0036] Another embodiment of the present invention provides a method for preparing a conversion film on a metal surface, wherein a copper alloy is pickled with a nitric acid solution, and then the pickled copper alloy is immersed in the above-mentioned cage-type silsesquioxane treatment solution for film-forming treatment, so that a chemical conversion film is formed on the surface of the pickled copper alloy.

[0037] In some embodiments, the copper alloy is polished with an acidic polishing solution before pickling. Specifically, the acidic polishing solution contains phosphoric acid, sulfuric acid, nitric acid, and hydrochloric acid. Specifically, the polishing time is 3 to 10 seconds. Specifically, the polishing is followed by water washing.

[0038] In some embodiments, the pickling treatment lasts for 30 to 60 seconds. Specifically, the pickling treatment is followed by water washing. More specifically, the water washing is followed by drying.

[0039] In some embodiments, during the pickling process, the mass concentration of the nitric acid solution is 30-50%.

[0040] In some embodiments, the film forming process is performed at a temperature of 20 to 80° C. for 10 to 120 minutes, and then dried.

[0041] A third embodiment of the present invention provides a cage-type silsesquioxane treatment liquid for treating the surface of a steel alloy, wherein the treatment liquid contains octaaminopropyl silsesquioxane at a mass concentration of 0.05 to 5%. The pH value of the treatment liquid is adjusted to acidic using an organic acid.

[0042] In some embodiments, the mass concentration of octaaminopropylsilsesquioxane in the treatment solution is 0.05 to 1.0%, preferably 0.05 to 0.5%, and more preferably 0.1 to 0.5%.

[0043] In some embodiments, the invention further comprises an additive at a mass concentration of 0.2 to 1.0%, wherein the additive is tetraethyl orthosilicate and / or aminopropyl triethoxysilane. Specifically, the additive is tetraethyl orthosilicate and aminopropyl triethoxysilane; preferably, the mass ratio of tetraethyl orthosilicate to aminopropyl triethoxysilane is 1:0.9 to 1.1.

[0044] In some embodiments, the organic acid is acetic acid, which has less steric hindrance and better effect.

[0045] In some embodiments, the pH value of the treatment solution is adjusted to 4-8.

[0046] In some embodiments, the solvent of the treatment liquid is a mixture of ethanol and water, specifically, the volume ratio of ethanol to water is 1:3.5-4.5.

[0047] A fourth embodiment of the present invention provides a method for preparing a conversion film on a metal surface, wherein a steel alloy is pickled with a nitric acid solution, and then the pickled steel alloy is immersed in the above-mentioned cage-type silsesquioxane treatment solution for film-forming treatment, so that a chemical conversion film is formed on the surface of the pickled steel alloy.

[0048] In some embodiments, the steel alloy is degreased before pickling. Specifically, the degreasing process involves immersing the steel alloy in a solution containing a degreasing agent and then scrubbing the steel alloy until the surface becomes hydrophilic. Specifically, the immersion time is 5 to 15 minutes.

[0049] In some embodiments, the film forming process is performed at a temperature of 20 to 80° C. for 3 to 30 minutes, and then dried.

[0050] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments and comparative examples.

[0051] Example 1

[0052] Synthesis of 3-mercaptopropylsilsesquioxane (octamercaptopropylsilsesquioxane): 3-mercaptopropyltrimethoxysilane (30 mL) and 38% concentrated hydrochloric acid (60 mL) were mixed with methanol (500 mL) and then stirred at 90°C. A white precipitate was formed after 24 hours. Finally, POSS-(SH)8 (abbreviated as POSS-SH) was isolated and purified. Figure 1 shown.

[0053] A cage-type silsesquioxane treatment liquid is prepared by using a mixture of tetrahydrofuran and water in a volume ratio of 1:1 as a solvent, adding octamercaptopropyl silsesquioxane to the solvent so that the mass concentration of octamercaptopropyl silsesquioxane in the treatment liquid is 0.3% and mixing the mixture evenly, and then adjusting the pH value of the solution to 4 using an acetic acid solution to obtain the obtained solution.

[0054] A method for preparing a conversion film on a copper metal surface comprises the following steps:

[0055] (1) A commercial copper sheet was immersed in a polishing solution (85% concentrated phosphoric acid, 98% concentrated sulfuric acid, 68% concentrated nitric acid, industrial water, and 38% concentrated hydrochloric acid in a mass ratio of 25:30:20:24:1) and polished at room temperature for 4 seconds, and then immediately rinsed with plenty of water.

[0056] (2) Immerse the polished copper sheet in a pickling solution (68% concentrated nitric acid and industrial water in a mass ratio of 50:50) at room temperature for 30 seconds to 1 minute, and immediately rinse with plenty of water. Blow dry the pickled copper sheet with a fan.

[0057] (3) The copper sheet prepared in step (3) was immersed in the cage-type silsesquioxane treatment solution prepared in this example, treated at 60° C. for 30 min, rinsed with the corresponding solvent (tetrahydrofuran and water in a volume ratio of 1:1), and then blown dry.

[0058] Example 2

[0059] A cage-type silsesquioxane treatment liquid is prepared by using a mixture of tetrahydrofuran and water in a volume ratio of 1:1 as a solvent, adding octamercaptopropyl silsesquioxane and neodymium nitrate to the solvent so that the mass concentration of octamercaptopropyl silsesquioxane in the treatment liquid is 0.3% and the concentration of neodymium nitrate is 4 g / L, and mixing the mixture uniformly. Then, an acetic acid solution is used to adjust the pH value of the solution to 4, thereby obtaining the obtained solution.

[0060] A method for preparing a conversion film on a copper metal surface comprises the following steps:

[0061] (1) Immerse a commercial copper sheet in a polishing solution (25% phosphoric acid, 30% sulfuric acid, 20% nitric acid, 24% industrial water, 1% hydrochloric acid) and polish it at room temperature for 4 seconds, and immediately rinse it with plenty of water.

[0062] (2) Immerse the polished copper sheet in a pickling solution (50% nitric acid, 50% industrial water) at room temperature for 30 seconds to 1 minute, and immediately rinse with plenty of water. Blow dry the pickled copper sheet with a fan.

[0063] (3) The copper sheet prepared in step (3) was immersed in the cage-type silsesquioxane treatment solution prepared in this example, treated at 60° C. for 30 min, rinsed with the corresponding solvent (tetrahydrofuran and water in a volume ratio of 1:1), and then blown dry.

[0064] Comparative Example 1

[0065] A method for preparing a conversion film on a copper metal surface comprises the following steps:

[0066] (1) Immerse a commercial copper sheet in a polishing solution (25% phosphoric acid, 30% sulfuric acid, 20% nitric acid, 24% industrial water, 1% hydrochloric acid) and polish it at room temperature for 4 seconds, and immediately rinse it with plenty of water.

[0067] (2) Immerse the polished copper sheet in a pickling solution (50% nitric acid, 50% industrial water) at room temperature for 30 seconds to 1 minute, and immediately rinse with plenty of water. Blow dry the pickled copper sheet with a fan.

[0068] Comparative Example 2

[0069] (1) The copper sheet obtained in Comparative Example 1 was immersed in a 0.3% pentaerythritol tetrathioglycolate solution at 60° C. for 30 min, rinsed with a corresponding solvent (the volume ratio of tetrahydrofuran to water was 1:1) and then blown dry.

[0070] The open circuit potential of the copper sheets after treatment in Examples 1, 2 and Comparative Example 1 was tested, and the AC impedance was further measured. The results are as follows: Figure 2 As shown, the capacitance arc radius of Example 2 is significantly larger than that of Example 1 and Comparative Example 1, which indicates that rare earth metal-doped octamercaptopropyl silsesquioxane has much greater corrosion resistance than bare copper and single octamercaptopropyl silsesquioxane.

[0071] AFM mechanical properties test Figure 3 As shown, the results show that the adhesion of Example 1 and Example 2 are similar, both around 60nN, and are higher than that of Comparative Example 2, which is 40nN of common carbon-based thiol materials, indicating that the presence of octamercaptopropyl silsesquioxane improves the adhesion of the film layer.

[0072] Nanoindentation test results are as follows Figure 4 As shown, the experimental results show that the hardness and elastic modulus of the film layers of Examples 1 and 2 are much higher than those of the conventional carbon-based thiol material of Comparative Example 2, and the hardness of the film layer is positively correlated with the wear resistance, indicating that the presence of octamercaptopropyl silsesquioxane greatly improves the hardness and wear resistance of the film layer.

[0073] The contact angle test results are as follows Figure 5 As shown, the experimental results show that the contact angle of comparative example 1 is 27.8°, which has good wettability, while the contact angles of embodiment 1 and embodiment 2 are both above 100°, indicating that the formation of the POSS layer improves the hydrophobicity of the film layer and realizes the construction of a hydrophobic surface.

[0074] Example 3

[0075] A cage-type silsesquioxane treatment liquid is prepared by using a mixture of ethanol and water in a volume ratio of 2:8 as a solvent, adding octaaminopropyl silsesquioxane to the solvent so that the mass concentration of octaaminopropyl silsesquioxane in the treatment liquid is 0.3% and mixing the mixture evenly, and then adjusting the pH value of the solution to 4 using an acetic acid solution to obtain the obtained solution.

[0076] A method for preparing a conversion coating on a steel plate surface comprises the following steps:

[0077] (1) Degrease the commercial steel plate in a degreasing agent and soak it at room temperature for 10 minutes. Scrub the steel plate with a sponge until the surface of the steel plate becomes hydrophilic.

[0078] (2) The steel plate treated in step (1) was immersed in the cage-type silsesquioxane treatment solution prepared in this example, treated at room temperature for 10 minutes, rinsed with the corresponding solvent (ethanol to water volume ratio of 2:8) and then blown dry.

[0079] Example 4

[0080] A cage-type silsesquioxane treatment liquid is prepared by using a mixture of ethanol and water in a volume ratio of 2:8 as a solvent, adding octaaminopropyl silsesquioxane and tetraethyl orthosilicate into the solvent so that the mass concentration of octaaminopropyl silsesquioxane and the mass concentration of tetraethyl orthosilicate in the treatment liquid are 0.3% and the mixture is uniformly mixed, and then adjusting the pH value of the solution to 4 using an acetic acid solution to obtain the treatment liquid.

[0081] A method for preparing a conversion coating on a steel plate surface comprises the following steps:

[0082] (1) Degrease the commercial steel plate in a degreasing agent and soak it at room temperature for 10 minutes. Scrub the steel plate with a sponge until the surface of the steel plate becomes hydrophilic.

[0083] (2) The steel plate treated in step (1) was immersed in the cage-type silsesquioxane treatment solution prepared in this example, treated at room temperature for 10 minutes, rinsed with the corresponding solvent (ethanol to water volume ratio of 2:8) and then blown dry.

[0084] Example 5

[0085] A cage-type silsesquioxane treatment liquid is prepared by using a mixture of ethanol and water in a volume ratio of 2:8 as a solvent, adding octaaminopropyl silsesquioxane and aminopropyl triethoxysilane into the solvent so that the mass concentration of octaaminopropyl silsesquioxane and the mass concentration of aminopropyl triethoxysilane in the treatment liquid are 0.3% and the mixture is uniformly mixed, and then adjusting the pH value of the solution to 4 using an acetic acid solution to obtain the treatment liquid.

[0086] A method for preparing a conversion coating on a steel plate surface comprises the following steps:

[0087] (1) Degrease the commercial steel plate in a degreasing agent and soak it at room temperature for 10 minutes. Scrub the steel plate with a sponge until the surface of the steel plate becomes hydrophilic.

[0088] (2) The steel plate treated in step (1) was immersed in the cage-type silsesquioxane treatment solution prepared in this example, treated at room temperature for 10 minutes, rinsed with the corresponding solvent (ethanol to water volume ratio of 2:8) and then blown dry.

[0089] Example 6

[0090] A cage-type silsesquioxane treatment liquid is prepared by using a mixture of ethanol and water in a volume ratio of 2:8 as a solvent, adding octaaminopropyl silsesquioxane, tetraethyl orthosilicate and aminopropyl triethoxysilane into the solvent so that the mass concentration of octaaminopropyl silsesquioxane, the mass concentration of tetraethyl orthosilicate and the mass concentration of aminopropyl triethoxysilane in the treatment liquid are 0.3%, mixing them uniformly, and then adjusting the pH value of the solution to 4 using an acetic acid solution to obtain the treatment liquid.

[0091] A method for preparing a conversion coating on a steel plate surface comprises the following steps:

[0092] (1) Degrease the commercial steel plate in a degreasing agent and soak it at room temperature for 10 minutes. Scrub the steel plate with a sponge until the surface of the steel plate becomes hydrophilic.

[0093] (2) The steel plate treated in step (1) was immersed in the cage-type silsesquioxane treatment solution prepared in this example, treated at room temperature for 10 minutes, rinsed with the corresponding solvent (ethanol to water volume ratio of 2:8) and then blown dry.

[0094] Comparative Example 1

[0095] A method for preparing a conversion film on a steel plate surface comprises degreasing a commercial steel plate in a degreasing agent, soaking the steel plate at room temperature for 10 minutes, and scrubbing the steel plate with a sponge until the surface of the steel plate becomes hydrophilic.

[0096] The open circuit potential of the steel sheets after treatment in Examples 3 to 6 and Comparative Example 2 was tested, and the AC impedance was further measured. The results are as follows: Figure 6As shown, the size of the capacitance arc radius reflects the strength of the corrosion resistance of the film layer. The sizes of the capacitance arc radius are Example 6 > Example 5 > Example 3 > Example 4 > Comparative Example 2. This shows that when aminopropyltriethoxysilane and tetraethyl orthosilicate are added to the solution at the same time, the synergistic effect of the three plays a key role in improving the corrosion protection ability of the conversion film, so that the three-component chemical conversion film can provide the best anti-corrosion effect.

[0097] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A cage-type silsesquioxane treatment liquid, characterized in that: The method is used for treating the surface of copper alloy. The treatment liquid contains octamercaptopropylsilsesquioxane with a mass concentration of 0.05-5%. The pH value of the treatment liquid is adjusted to be acidic by using organic acid.

2. The cage-type silsesquioxane treatment solution according to claim 1, wherein The mass concentration of octamercaptopropylsilsesquioxane in the treatment liquid is 0.05 to 1.0%, preferably 0.05 to 0.5%, and more preferably 0.1 to 0.5%; Or, it further includes an additive with a concentration of 1 to 10 g / L, wherein the additive is a rare earth salt; preferably, in the treatment liquid, the concentration of the additive is 2 to 6 g / L, preferably 3 to 5 g / L; preferably, the rare earth salt is a rare earth nitrate, preferably one of lanthanum nitrate, yttrium nitrate, neodymium nitrate, cerium nitrate, and zirconium nitrate.

3. The cage-type silsesquioxane treatment solution according to claim 1, wherein: The organic acid is acetic acid; Or, the pH value of the treatment liquid is adjusted to 4 to 6; Alternatively, the solvent of the treatment liquid is a mixture of tetrahydrofuran and water; preferably, the volume ratio of tetrahydrofuran to water is 1:0.9-1.

1.

4. A method for preparing a conversion film on a metal surface, characterized in that: The copper alloy is pickled with a nitric acid solution, and then immersed in the cage-type silsesquioxane treatment solution according to any one of claims 1 to 3 for film-forming treatment, so that a chemical conversion film is formed on the surface of the pickled copper alloy.

5. The method according to claim 4, wherein: Before the pickling treatment, the copper alloy is polished with an acidic polishing liquid; preferably, the acidic polishing liquid contains phosphoric acid, sulfuric acid, nitric acid and hydrochloric acid; preferably, the polishing time is 3 to 10 seconds; Alternatively, the pickling treatment time is 30 to 60 seconds; Alternatively, during the pickling treatment, the mass concentration of the nitric acid solution is 30-50%; Alternatively, the film forming treatment is performed at a temperature of 20 to 80° C. and for a time of 10 to 120 minutes.

6. A cage-type silsesquioxane treatment solution, characterized in that: The invention is used for treating the surface of steel alloy. The treatment liquid contains octaaminopropyl silsesquioxane with a mass concentration of 0.05-5%. The pH value of the treatment liquid is adjusted to be acidic by using organic acid.

7. The cage-type silsesquioxane treatment solution according to claim 6, wherein: The mass concentration of octaaminopropylsilsesquioxane in the treatment liquid is 0.05 to 1.0%, preferably 0.05 to 0.5%, and more preferably 0.1 to 0.5%; Alternatively, the invention further comprises an additive with a mass concentration of 0.2 to 1.0%, wherein the additive is tetraethyl orthosilicate and / or aminopropyltriethoxysilane; preferably, the additive is tetraethyl orthosilicate and aminopropyltriethoxysilane; preferably, the mass ratio of tetraethyl orthosilicate to aminopropyltriethoxysilane is 1:0.9 to 1.

1.

8. The cage-type silsesquioxane treatment solution according to claim 6, wherein: The organic acid is acetic acid; Or, the pH value of the treatment liquid is adjusted to 4 to 8; Alternatively, the solvent of the treatment liquid is a mixture of ethanol and water; preferably, the volume ratio of ethanol to water is 1:3.5-4.

5.

9. A method for preparing a conversion film on a metal surface, characterized in that: The steel alloy is pickled with a nitric acid solution, and then immersed in the cage-type silsesquioxane treatment solution according to any one of claims 6 to 8 for film-forming treatment, so that a chemical conversion film is formed on the surface of the pickled steel alloy.

10. The method according to claim 9, wherein: Before pickling, the steel alloy is degreased; preferably, the degreasing treatment is: adding the steel alloy to a solution containing a degreasing agent and soaking it, and then scrubbing it until the surface of the steel alloy becomes hydrophilic; preferably, the soaking time is 5 to 15 minutes; Alternatively, the film forming treatment is performed at a temperature of 20 to 80° C. for 3 to 30 minutes.

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