Preparation method of anti-ultraviolet corrosion inhibition film on surface of metal cultural relic

Abstract

The invention discloses a preparation method of an anti-ultraviolet corrosion inhibition film on the surface of a metal cultural relic, which comprises the following steps: firstly, pretreating the surface of a metal cultural relic sample by using gamma-aminopropyltriethoxysilane, and then immersing the metal cultural relic sample into a vinyl trimethoxy silane doped nano CeO2 precursor solution; a compact and flat anti-ultraviolet corrosion inhibition film with the thickness of about 20 microns is formed on the surface of a metal cultural relic sample through regulation and control, the corrosion inhibition efficiency can reach 92.4% at most, after a 60-day ultraviolet accelerated aging experiment, the corrosion inhibition efficiency still reaches 80.7%, and excellent weather resistance is shown. The anti-ultraviolet corrosion inhibition film provides important technical support and key reference data for building a long-acting corrosion inhibition film for metal cultural relics such as museum collection bronze ware, and can be applied to the fields of metal cultural relic protection, metal handicraft protection, industrial metal corrosion prevention and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of cultural relics protection, and particularly relates to a method for preparing a weather-resistant corrosion inhibition film on the surface of metal cultural relics by utilizing a nano inorganic light stabilizer and a low-energy surface material. Background Art

[0002] The corrosion process of bronze is a complex phenomenon, which is affected by multiple factors such as material composition, environmental medium and corrosion products. Light may affect the corrosion behavior of metals by changing the semiconductor properties of corrosion products. For example, common corrosion products on the surface of weathering steel, such as γ-FeOOH and β-FeOOH, have been shown to promote the corrosion process of weathering steel in NaCl solution under the photovoltaic effect of visible light (see the papers "The Role of the Photovoltaic Effect of γ-FeOOH and β-FeOOH on the Corrosion of 09CuPCrNi Weathering Steel under Visible Light" and "The Role of UV Illumination on the Initial Atmospheric Corrosion of 09CuPCrNi Weathering Steel in the Presence of NaCl Particles"). There are also studies (see the paper "Preparation of Cuprous Oxides with Different Sizes and Their Behaviors of Adsorption, Visible-Light Driven Photocatalysis"). and Photocorrosion》) shows that ultraviolet light irradiation accelerates the formation of Cu2O on the surface of pure copper. The photoresponse characteristics of the main corrosion products Cu2O and SnO2 on the bronze surface directly determine the influence mechanism of light. Ultraviolet light can promote the corrosion of bronze due to its high-energy photons (see the master's thesis "Corrosion Behavior and Mechanism of Bronze in Aqueous Solutions under Visible and Ultraviolet Light").

[0003] In addition, metal cultural relics using organic corrosion inhibition and sealing materials are also prone to photodegradation (see the master's thesis "Research on Photoaging Modification of Commonly Used Organic Polymer Cultural Relics Protection Materials"), which is also an area of ​​increasing concern for cultural relic protection materials. Therefore, the use of light stabilizers to increase the weather resistance of cultural relic protection materials has become an important research direction. Among them, the ultraviolet absorber UV-328 has been used in cultural relic protection to resist the photoaging of common organic materials such as propylene epoxy resin (see the papers "Application of Light Stabilizers in the Modification of Organic Polymer Cultural Relics Protection Materials" and "Research on Light Stabilizers for Epoxy Resins Used in Cultural Relic Protection").

[0004] Therefore, the construction of a corrosion-inhibiting film with UV resistance on the surface of metal cultural relics is not only beneficial to the anti-photooxidation of the metal cultural relics themselves, but also helps to improve the corrosion-inhibiting film's own resistance to UV aging. In theory, it can greatly improve the stability of the corrosion-inhibiting film and thus prolong its protective effect. Cerium dioxide (CeO2) has a wide range of uses and can be used as a pigment, corrosion inhibitor and light stabilizer. Among them, CeO2 is often added to epoxy coatings and will release CeO2. 3+ The -OH groups in the particle capture coating form dense Ce(OH)3 and Ce(OH)4 passivation layers on the metal surface, inhibiting corrosion (see the paper "Preparation and Properties of CeO2-GO / EP Anticorrosion Composite Coatings"). Alternatively, they can directly form an oxide anticorrosion film on the metal surface. However, preventing the decomposition of CeO2 and the formation of Ce(OH)3 and Ce(OH)4 passivation layers from affecting the appearance of cultural relics, while fully utilizing the CeO2 light stabilizer function, has become an important research direction for the application of this type of material in the demanding field of cultural relic preservation. Summary of the Invention

[0005] The purpose of the present invention is to provide a simple and efficient method for preparing a corrosion inhibition film on the surface of a metal cultural relic with strong adhesion, uniform thickness, dense structure and UV resistance.

[0006] The method for preparing the anti-ultraviolet corrosion-inhibiting film on the surface of metal cultural relics provided by the present invention comprises the following steps:

[0007] Step 1: Surface pretreatment of metal artifact samples

[0008] The degreased metal artifact sample is immersed in a γ-aminopropyltriethoxysilane hydrolyzate for 10 to 30 minutes, taken out and placed in an oven for curing at 80 to 120° C. for 0.5 to 2 hours to obtain a surface-pretreated metal artifact sample.

[0009] Step 2: Vinyltrimethoxysilane doped nano-CeO2 precursor solution treatment

[0010] Nano-CeO2 particles are added to vinyltrimethoxysilane hydrolyzate and ultrasonically dispersed for 0.5 to 1 hour to obtain a vinyltrimethoxysilane-doped nano-CeO2 precursor solution; a surface-pretreated metal cultural relic sample is placed in the vinyltrimethoxysilane-doped nano-CeO2 precursor solution and immersed for 20 to 40 minutes, taken out and placed in an oven for curing at 60 to 90°C for 5 to 20 minutes to obtain a metal cultural relic sample with an anti-ultraviolet corrosion inhibition film formed on the surface.

[0011] In step 1 above, the γ-aminopropyltriethoxysilane hydrolyzate is prepared by mixing γ-aminopropyltriethoxysilane, anhydrous ethanol, and deionized water, uniformly dispersing the mixture through ultrasonication, adjusting the pH of the mixture to 4-6 with aqueous ammonia, and hydrolyzing the mixture in a constant temperature water bath at 30-50° C. for 4-8 hours to obtain the γ-aminopropyltriethoxysilane hydrolyzate. Preferably, the volume ratio of the γ-aminopropyltriethoxysilane, anhydrous ethanol, and deionized water is 2-5:8-12:83-90.

[0012] In the above step 1, curing is further preferably performed at 100° C. for 1 hour.

[0013] In the above step 2, the particle size of the nano-CeO2 particles is 75 to 150 nm.

[0014] In step 2 above, the vinyltrimethoxysilane hydrolyzate is prepared by mixing vinyltrimethoxysilane, anhydrous ethanol, and deionized water, uniformly dispersing the mixture with ultrasonic waves, adjusting the pH of the mixture to 3-5 with glacial acetic acid, and hydrolyzing the mixture in a constant temperature water bath at 20-30° C. for 1-3 hours to obtain the vinyltrimethoxysilane hydrolyzate. Preferably, the volume ratio of the vinyltrimethoxysilane, anhydrous ethanol, and deionized water is 4-8:4-8:85-92.

[0015] In the above step 2, the preferred addition ratio of the nano-CeO2 particles to the vinyltrimethoxysilane hydrolyzate is 50-250 mg:1 L.

[0016] In the above step 2, curing is further preferably performed at 80° C. for 10 minutes.

[0017] The beneficial effects of the present invention are as follows:

[0018] 1. The present invention utilizes the -OCH3CH4 in the γ-aminopropyltriethoxysilane (APTES) molecule to condense with the -OH on the metal surface to form M-Si-O, while the terminal amino group (-NH2) can form a strong coordination bond with the metal ions of the metal surface oxide, thereby improving the surface properties of the metal and increasing the adhesion of the corrosion inhibition film. An aqueous solution containing vinyltrimethoxysilane (VTMS) and CeO2 is used as a precursor solution. The vinyl group (-CH=CH2) in VTMS is easily grafted and polymerized with the hydrogen-containing group in APTES when irradiated with light, thereby bonding with the APTES pre-treated surface when fixing the CeO2 nanoparticles through the M-Si-O bond to form a dense corrosion inhibition film. The present invention is based on the coating of CeO2 nanoparticles by VTMS and its super hydrophobic properties to effectively avoid Ce 3+ and Ce 4+ At the same time, the APTES modification layer is used to increase the adhesion of the corrosion inhibition layer and prevent CeO2 from forming an oxide layer due to direct contact with the metal surface, providing a solid isolation layer for stabilizing the presence of CeO2 and exerting its anti-ultraviolet function.

[0019] 2. The method of the present invention can form a dense and smooth UV-resistant corrosion-inhibiting film approximately 20 μm thick on the surface of metal artifacts, with a corrosion inhibition efficiency of up to 92.4%. After 60 days of UV-accelerated aging, the corrosion inhibition efficiency remained as high as 80.7%, demonstrating excellent weather resistance. This weather-resistant corrosion-inhibiting film provides important technical support and key reference data for the establishment of long-lasting corrosion-inhibiting films on metal artifacts such as bronze artifacts in museum collections, and can be used in the fields of metal artifact conservation, metal craft protection, and industrial metal corrosion prevention. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 These are the contact angle diagrams of the surface film layer of the bronze sample treated with different contents of nano-CeO2+VTMS precursor solution in Comparative Example 1 (a is 0g, b is 0.005g, c is 0.015g, and d is 0.025g).

[0021] Figure 2 These are the electrochemical test diagrams of the bronze samples treated with different contents of nano-CeO2+VTMS precursor solution in 3.5% NaCl corrosion medium in Comparative Example 1 (a is the Tafel polarization curve, b is the impedance Nyquist diagram, c and d are Bode diagrams).

[0022] Figure 3 These are the SEM morphology (left) and cross-sectional view (right) of the corrosion inhibition film of the bronze sample treated with 0.015g nano-CeO2+VTMS precursor solution in Comparative Example 1.

[0023] Figure 4These are the contact angle diagrams of the surface film layer of the bronze sample pretreated with APTES in Example 1 after being treated with different contents of nano-CeO2+VTMS precursor solution (a is 0g, b is 0.005g, c is 0.015g, and d is 0.025g).

[0024] Figure 5 This is the Tafel polarization curve of bronze samples treated under different conditions in 3.5% NaCl corrosive medium.

[0025] Figure 6 These are SEM morphologies of the bronze samples treated under different conditions (a is 0g, b is 0.005g, c is 0.015g, and d is 0.025g).

[0026] Figure 7 This is the element mapping diagram of the surface film layer of the bronze sample pretreated with APTES in Example 1 after being treated with different contents of nano-CeO2+VTMS precursor solution (a is 0.005g, b is 0.015g, and c is 0.025g).

[0027] Figure 8 This is the SEM morphology (left) and cross-sectional view (right) of the surface film layer of the bronze sample pretreated with APTES in Example 1 after being treated with 0.015g of nano-CeO2+VTMS precursor solution.

[0028] Figure 9 This is a histogram of color difference data of the surface film layer of the bronze sample pretreated with APTES in Example 1 after being treated with nano-CeO2+VTMS precursor solutions with different contents.

[0029] Figure 10 These are morphologies of bronze samples with different UV aging times, where a is bare bronze irradiated with UV for 7 days, b, c, d, and e are the corrosion inhibition films formed after the bronze sample pretreated with APTES in Example 1 was treated with 0.015 g of nano-CeO2 + VTMS precursor solution without UV aging, UV aging for 7 days, UV aging for 30 days, and UV aging for 60 days, respectively.

[0030] Figure 11 These are the electrochemical test graphs of the corrosion inhibition film formed on bare bronze (KB) after UV aging for 7 days and the bronze sample pretreated with APTES in Example 1 and treated with 0.015g nano-CeO2+VTMS precursor solution in 3.5% NaCl corrosion medium at different UV aging times (a is the Tafel polarization curve, b is the impedance Nyquist diagram, c and d are Bode diagrams). DETAILED DESCRIPTION

[0031] The present invention will be further described in detail below with reference to the accompanying drawings and examples, but the protection scope of the present invention is not limited to these examples.

[0032] The nano-CeO particles used in the embodiment were prepared by a precipitation method. The specific preparation method is as follows: 40 mL of a 0.25 mol / L aqueous cerium nitrate solution was placed in a three-necked flask, followed by the slow addition of a 0.375 mol / L aqueous ammonium carbonate solution, with continuous and vigorous stirring during the addition process. After the solution was uniformly mixed, the reaction was maintained at a constant temperature for 30 minutes. After the reaction was completed, the mixed solution was transferred to a reflux reactor and stirred at 100°C for 12 hours. After stopping the reaction, the solution was naturally cooled to room temperature and centrifuged. The supernatant was discarded, and the precipitate was washed twice with deionized water and twice with anhydrous ethanol to remove impurities. After washing, the precipitate was dried in a 70°C constant temperature drying oven. The dried sample was ground, placed in a muffle furnace, and calcined at 500°C for 4 hours to obtain milky yellow, fine, and loose nano-CeO particles with a particle size of 75 to 150 nm.

[0033] Comparative Example 1

[0034] VTMS, anhydrous ethanol, and deionized water were mixed in a volume ratio of 6:6:88 and ultrasonically dispersed. The mixture was then adjusted to pH 4 with glacial acetic acid and hydrolyzed in a 25°C water bath for 2 hours to obtain a VTMS hydrolyzate. 0g, 0.005g, 0.015g, and 0.025g of nano-CeO2 particles with a particle size of 75-150nm were added to 100mL of the VTMS hydrolyzate and ultrasonically dispersed for 1 hour to obtain nano-CeO2+VTMS precursor solutions with different contents. Degreased bronze samples were placed in the precursor solutions, suspended and soaked for 30 minutes, then removed and cured in an oven at 80°C for 10 minutes to obtain bronze samples with a corrosion-inhibiting film formed on the surface.

[0035] Figure 1 This is the contact angle of the bronze sample surface after treatment with different contents of nano-CeO2+VTMS precursor solution, which shows that the addition of nano-CeO2 can enhance the hydrophobicity of the corrosion inhibition film. Among them, the corrosion inhibition film with 0.015g nano-CeO2 added exhibits the best hydrophobicity, with a contact angle value of 94.8°. Figure 2 The electrochemical test diagram of bronze samples after being treated with different contents of nano-CeO2+VTMS precursor solution shows that the bronze sample with an addition amount of nano-CeO2 of 0.015g exhibits the best electrochemical performance, with a corrosion inhibition efficiency of up to 92.2%. Figure 3 This is the SEM morphology of the surface and cross-section of the bronze sample treated with 0.015g CeO2+VTMS precursor solution. It can be observed that there is a contact gap between the corrosion inhibition film and the underlying layer, and the thickness is uneven, and there is local damage.

[0036] Example 1

[0037] Step 1: Surface pretreatment of metal artifact samples

[0038] APTES, anhydrous ethanol, and deionized water were mixed in a volume ratio of 2:8:90 and ultrasonically dispersed. The mixture was then adjusted to pH 5 with aqueous ammonia and hydrolyzed in a 40°C water bath for 6 hours to obtain an APTES hydrolyzate. Degreased bronze specimens were then placed in the APTES hydrolyzate, suspended and immersed for 15 minutes. The specimens were then removed and cured in an oven at 100°C for 1 hour to obtain APTES-pretreated bronze specimens.

[0039] Step 2: VTMS doped nano-CeO2 precursor solution treatment

[0040] VTMS, anhydrous ethanol, and deionized water were mixed in a volume ratio of 6:6:88, ultrasonically dispersed, and the pH of the mixture was adjusted to 4 with glacial acetic acid. The mixture was hydrolyzed in a constant temperature water bath at 25°C for 2 hours to obtain a VTMS hydrolyzate. 0g, 0.005g, 0.015g, and 0.025g of nano-CeO2 particles with a particle size of 75-150nm were added to 100mL of the VTMS hydrolyzate and ultrasonically dispersed for 1 hour to obtain nano-CeO2+VTMS precursor solutions with different contents. The bronze samples pretreated with APTES in step 1 were placed in the precursor solution, suspended and soaked for 30 minutes, and then removed and placed in an oven for curing at 80°C for 10 minutes to obtain bronze samples with an anti-UV corrosion inhibition film formed on the surface.

[0041] Figure 4 This is a video contact angle diagram of the surface film layer of the bronze sample pretreated with APTES after being treated with different contents of nano-CeO2+VTMS precursor solution. It shows that the hydrophobicity of the corrosion inhibition film after treatment with CeO2+VTMS precursor solution is significantly increased after the APTES pretreatment process, and the film with 0.025g of nano-CeO2 is as high as 114.8°. Figure 5 This is the Tafel polarization curve of bronze samples treated under different conditions in a 3.5% NaCl corrosion medium, showing that the corrosion inhibition efficiency of the corrosion inhibition film formed by adding 0.025g of nano-CeO2 is the highest at 92.4%, indicating that the APTES pretreatment induces the film formation process to reduce the agglomeration of nanoparticles (see the maximum corrosion inhibition efficiency shown by the addition of 0.015g of nano-CeO2 in Comparative Example 1). Figure 6 The SEM morphology of the bronze sample surface treated under different conditions shows that the addition of 0.015g nano-CeO2 forms the smoothest corrosion inhibition film, in which the element distribution is also very uniform. Figure 7 . Figure 8 It shows that the corrosion inhibition film formed by adding 0.015g nano-CeO2 has uniform thickness, dense structure, and close contact with the bronze substrate. Their color difference is less than 5, which meets the requirements of cultural relics protection. Figure 9 . Figure 10The surface morphology of bronze samples with different UV aging times shows that the corrosion inhibition film formed after the bronze sample pretreated with APTES and treated with 0.015g nano-CeO2+VTMS precursor solution still maintains a complete surface morphology after 7 days of UV aging. When the aging time is extended to 30 days, the corrosion inhibition film begins to wrinkle. After continuing to age for 60 days, a small number of holes appear in the film layer, and the coating ability of the corrosion inhibition film decreases. Figure 11 This is the electrochemical test diagram of bronze samples in NaCl corrosive medium after different UV aging times (days), showing that the corrosion inhibition efficiency is still as high as 80.7% after 60 days of UV aging, indicating that the corrosion inhibition film formed by adding 0.015g nano-CeO2 has better UV resistance.

Claims

1. A method for preparing an anti-ultraviolet corrosion inhibitor film on the surface of a metal cultural relic, characterized in that It consists of the following steps: Step 1: Surface pretreatment of metal artifact samples The degreased metal artifact sample is immersed in a γ-aminopropyltriethoxysilane hydrolyzate for 10 to 30 minutes, taken out and placed in an oven for curing at 80 to 120° C. for 0.5 to 2 hours to obtain a surface-pretreated metal artifact sample; Step 2: Vinyltrimethoxysilane doped nano-CeO2 precursor solution treatment Nano-CeO2 particles are added to vinyltrimethoxysilane hydrolyzate and ultrasonically dispersed for 0.5 to 1 hour to obtain a vinyltrimethoxysilane-doped nano-CeO2 precursor solution; a metal cultural relic sample with surface pretreatment is placed in the vinyltrimethoxysilane-doped nano-CeO2 precursor solution and immersed for 20 to 40 minutes, taken out and placed in an oven for curing at 60 to 90°C for 5 to 20 minutes to obtain a metal cultural relic sample with an anti-ultraviolet corrosion inhibition film formed on the surface.

2. The method for preparing the anti-ultraviolet corrosion-inhibiting film on the surface of metal cultural relics according to claim 1, characterized in that: In step 1, the preparation method of the γ-aminopropyltriethoxysilane hydrolyzate is as follows: γ-aminopropyltriethoxysilane, anhydrous ethanol, and deionized water are mixed, ultrasonically dispersed, and the pH of the mixture is adjusted to 4-6 with ammonia water, and hydrolyzed in a constant temperature water bath at 30-50° C. for 4-8 hours to obtain a γ-aminopropyltriethoxysilane hydrolyzate.

3. The method for preparing the anti-ultraviolet corrosion-inhibiting film on the surface of metal cultural relics according to claim 2, characterized in that: In step 1, the volume ratio of the γ-aminopropyltriethoxysilane, anhydrous ethanol, and deionized water is 2-5:8-12:83-90.

4. The method for preparing the anti-ultraviolet corrosion-inhibiting film on the surface of metal cultural relics according to claim 1, characterized in that: In step 1, curing was performed at 100°C for 1 hour.

5. The method for preparing the anti-ultraviolet corrosion-inhibiting film on the surface of metal cultural relics according to claim 1, characterized in that: In step 2, the particle size of the nano-CeO2 particles is 75 to 150 nm.

6. The method for preparing the anti-ultraviolet corrosion-inhibiting film on the surface of metal cultural relics according to claim 1, characterized in that: In step 2, the preparation method of the vinyltrimethoxysilane hydrolyzate is as follows: vinyltrimethoxysilane, anhydrous ethanol, and deionized water are mixed, ultrasonically dispersed, and the pH of the mixture is adjusted to 3-5 with glacial acetic acid, and hydrolyzed in a constant temperature water bath at 20-30° C. for 1-3 hours to obtain a vinyltrimethoxysilane hydrolyzate.

7. The method for preparing an anti-ultraviolet corrosion-inhibiting film on the surface of a metal cultural relic according to claim 6, characterized in that: In step 2, the volume ratio of the vinyltrimethoxysilane, anhydrous ethanol, and deionized water is 4-8:4-8:85-92.

8. The method for preparing an anti-ultraviolet corrosion-inhibiting film on the surface of a metal cultural relic according to claim 1, characterized in that: In step 2, the addition ratio of the nano-CeO2 particles to the vinyltrimethoxysilane hydrolyzate is 50-250 mg:1 L.

9. The method for preparing an anti-ultraviolet corrosion-inhibiting film on the surface of a metal cultural relic according to claim 1, characterized in that: In step 2, curing was performed at 80°C for 10 minutes.

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