Method for repairing and protecting iron cultural relics

Abstract

The invention discloses a method for repairing and protecting iron cultural relics, and belongs to the technical field of cultural relic protection. According to the method, cleaning, rust removal, desalination, corrosion inhibition and sealing protection are conducted on the iron cultural relics, a corrosion inhibition layer and a sealing protection layer are formed on the surfaces of the iron cultural relics, the corrosion inhibition layer is of a double-layer structure formed by a passivation film of sodium molybdate and a coordination film of BTA, the corrosion current density is remarkably reduced, the sealing protection layer isolates oxygen, water vapor and pollutants such as SO2 and Cl <-> in the environment, and the corrosion resistance of the iron cultural relics is improved. And moreover, the dense structure of the acrylate copolymer can effectively block liquid water permeation, so that the iron cultural relics can be protected from being corroded by acid gas pollutants in working and collection environments.

Description

Technical Field

[0001] This invention belongs to the field of cultural relic protection technology, specifically relating to a method for the restoration and protection of iron artifacts. Background Technology

[0002] Iron artifacts, buried deep underground or underwater for extended periods, undergo corrosion due to chemical and physical interactions with the surrounding environment, altering their composition, structure, and properties. While excavated iron artifacts are often stored in workshops or displayed in museums, the effectiveness of these protective layers is highly dependent on the air quality. Gaseous and solid pollutants in indoor air can form a water film on metal surfaces, leading to corrosion. Furthermore, with rapid socio-economic and industrial development, the types and amounts of pollutants in the atmosphere are constantly increasing, resulting in a corresponding increase in air pollutants in indoor working environments. Additionally, building materials, floors, display cases, and the adhesives and coatings used in museums release various organic acidic pollutants. These indoor air pollutants primarily include sulfur dioxide (SO2), hydrogen sulfide (H2S), and nitrogen oxides (NOx). X The substances involved include ozone (O3), formic acid (HCOOH), and acetic acid (CH3COOH). In high-humidity environments, SO2, H2S, NO2, HCOOH, and CH3COOH can all dissolve in the water film on the surface of iron artifacts, forming highly water-soluble and highly corrosive acids. Ozone and NO2 promote the oxidation of SO2 into sulfuric acid. These acids deposit on the metal surface and ionize to release H+. + The generated H + It will lower the pH value of the water film, accelerate the electrochemical corrosion process on the surface of iron artifacts, and may cause damage, failure and deterioration of the protective layer, thus exacerbating the corrosion of iron artifacts. Summary of the Invention

[0003] In view of the above-mentioned prior art, the present invention provides a method for the restoration and protection of iron artifacts, which protects iron artifacts from corrosion by acidic gaseous pollutants in working and museum environments.

[0004] This invention utilizes a composite solution of sodium molybdate and benzotriazole to provide multiple layers of protection through synergistic effects in the preservation of iron artifacts. Sodium molybdate acts as an anodic corrosion inhibitor, forming a passivation film of ferric molybdate (Fe2(MoO4)3) on the iron surface, thus inhibiting the electrochemical oxidation of iron (Fe→Fe). 2+ Its oxidizing properties can also promote the formation of a dense γ-Fe2O3 protective layer on the iron surface, because MoO4 2- The presence of [something] promotes the transformation of γ-FeOOH to Fe2O3, while stable oxides are formed, and MoO4 is adsorbed on the rust layer surface. 2- It can also react with the corrosion products Fe dissolved from the anode. 2+A reaction occurs within the rust layer, generating insoluble FeMoO4. The stable Fe2O3, MoO3, and FeMoO4 form a dense corrosion-inhibiting film, isolating the substrate from external corrosion and preventing further corrosion. Benzotriazole (BTA), as a cathodic corrosion inhibitor, reacts with Fe through nitrogen atoms... 2+ / Fe 3+ Coordination forms a [Fe(BTA)2] polymer film, covering the active sites and blocking redox reactions; because BTA forms N-Fe bonds with Fe, it is adsorbed on the substrate surface in the form of Fe-BTA complex, forming part of the corrosion inhibitor film.

[0005] Simultaneously, a 1wt% solution of ethyl methacrylate and methyl acrylate in ethyl acetate is used as a sealing liquid, which forms a transparent and continuous polymer film on the iron surface, reducing the damage of physical friction to the fragile rust layer. It is suitable for ironware with a loose surface or cultural relics with rust products.

[0006] To achieve the above objectives, the technical solution adopted by this invention is: to provide a method for the restoration and protection of iron artifacts, comprising the following steps: S1: Clean and remove rust from the surface of iron artifacts; S2: Desalination treatment is carried out on iron artifacts after cleaning and rust removal; S3: Apply corrosion inhibitor to the surface of iron artifacts after desalination treatment. After the surface of the iron artifacts dries naturally, apply corrosion inhibitor again. Then let the iron artifacts air dry naturally. The corrosion inhibitor is a composite solution of molybdenum salt and benzotriazole. S4: Apply a sealing liquid to the surface of the iron artifact that has been air-dried. After the surface of the iron artifact has dried naturally, apply another layer of sealing liquid and then let the iron artifact air-dry naturally.

[0007] Furthermore, the desalination process involves soaking the iron artifacts in deionized water and then drying the surface of the iron artifacts, with the soaking and drying steps being performed alternately.

[0008] Furthermore, the molybdenum salt is sodium molybdate.

[0009] Furthermore, the concentration of sodium molybdate in the corrosion inhibitor is 0.8~1.2wt%, and the concentration of benzotriazole is 0.4~0.6wt%.

[0010] Furthermore, the concentration of sodium molybdate in the corrosion inhibitor is 1 wt%, and the concentration of benzotriazole is 0.5 wt%.

[0011] Furthermore, the sealing solution is an ethyl acetate solution of ethyl methacrylate and methyl acrylate.

[0012] Furthermore, the mass ratio of ethyl methacrylate to methyl acrylate in the sealing solution is 34:66.

[0013] Furthermore, the concentration of the sealing solution is 1 wt%.

[0014] The beneficial effects of this invention are as follows: The method provided by this invention cleans, removes rust, desalinates, inhibits corrosion, and seals iron artifacts, forming an inhibitory layer and a sealing layer on the surface of the iron artifacts. The inhibitory layer is a bilayer structure formed by a passivation film of sodium molybdate and a coordination film of BTA, which significantly reduces the corrosion current density. The sealing layer is a transparent and continuous polymer film formed on the iron surface by an ethyl acetate solution of ethyl methacrylate and methyl acrylate, which isolates oxygen (O2), water vapor (H2O), and pollutants (such as SO2, Cl-) from the environment. - This polymer film slows down the oxidation and electrochemical corrosion of iron. Furthermore, its dense structure with low permeability effectively blocks liquid water penetration while allowing trace amounts of water vapor to pass through, preventing condensation buildup under the film. It also exhibits compatibility, adhering well to common corrosion products on iron surfaces (such as Fe2O3 and Fe3O4) without chemically reacting with the iron substrate, thus avoiding accelerated corrosion. In terms of wear resistance, this polymer film reduces the damage to fragile rust layers caused by physical friction, making it suitable for ironware with porous surfaces or artifacts with rust products. Attached Figure Description

[0015] Figure 1 XRD pattern of iron artifact a before rust removal, as shown in Example 1; Figure 2 XRD pattern of iron artifact a after rust removal, as shown in Example 1; Figure 3 XRD pattern of iron artifact a after desalination, as shown in Example 1; Figure 4 XRD pattern of iron artifact a after slow corrosion in Example 1; Figure 5 XRD pattern of iron artifact a after sealing in Example 1; Figure 6 pH values ​​of the surface microenvironment after corrosion inhibition, sealing, and corrosion inhibition + sealing treatments for glass slides; Figure 7 Example 1: pH changes in the surface microenvironment of iron artifact a. Figure 1 ; Figure 8 Example 1: pH changes in the surface microenvironment of iron artifact a. Figure 2 ; Figure 9 This is a diagram showing the pH changes in the microenvironment on the surface of iron artifact b, as shown in Example 2. Figure 10 This is a diagram showing the pH changes in the microenvironment on the surface of the iron artifact c in Example 3. Figure 11 This is a diagram showing the pH changes in the microenvironment of the iron artifact surface d in Example 4. Figure 12This is a diagram showing the pH changes in the microenvironment of the iron artifact e in Example 5. Figure 13 This is a diagram showing the pH changes in the microenvironment on the surface of the iron artifact f in Example 6. Detailed Implementation

[0016] The specific embodiments of the present invention will be described in detail below with reference to examples.

[0017] Example 1 A method for the restoration and preservation of iron artifacts includes the following steps: S1: Use tools such as scalpels, needles, and brushes to remove the crust and relatively loose rust layer on the surface of iron artifact a by picking, picking, peeling, and brushing. Then use a small grinder and dental scaler to clean the hard and stubborn rust on the surface of iron artifact a. S2: After soaking the cleaned and rust-removed iron artifact a in deionized water, dry the surface of iron artifact a. Repeat the soaking and drying steps 5 times to complete the desalination. S3: Use a brush to apply the corrosion inhibitor (a composite solution of sodium molybdate and benzotriazole, with the concentration of sodium molybdate in the corrosion inhibitor being 1 wt% and the concentration of benzotriazole being 0.5 wt%) to the surface of the desalinated iron artifact a. After the surface of the iron artifact a dries naturally, apply the corrosion inhibitor again and then let the iron artifact a air dry naturally. S4: Use a brush to apply the sealing solution (an ethyl acetate solution of ethyl methacrylate and methyl acrylate, with a mass ratio of ethyl methacrylate to methyl acrylate of 34:66 and a concentration of 1wt%) to the surface of the desalted iron artifact a. After the surface of iron artifact a dries naturally, apply the sealing solution again and then allow iron artifact a to air dry naturally.

[0018] Example 2 A method for the restoration and preservation of iron artifacts includes the following steps: S1: Use tools such as scalpels, needles, and brushes to remove the crust and relatively loose rust layer on the surface of iron artifact b by picking, picking, peeling, and brushing. Then use a small grinder and dental scaler to clean the hard and stubborn rust on the surface of iron artifact b. S2: After soaking the cleaned and rust-removed iron artifact b in deionized water, dry the surface of the iron artifact b. Repeat the soaking and drying steps 5 times to complete the desalination. S3: Use a brush to apply the corrosion inhibitor (a composite solution of sodium molybdate and benzotriazole, with the concentration of sodium molybdate in the corrosion inhibitor being 0.8wt% and the concentration of benzotriazole being 0.4wt%) to the surface of the desalinated iron artifact b. After the surface of the iron artifact b has dried naturally, apply the corrosion inhibitor again and then let the iron artifact b air dry naturally. S4: Use a brush to apply the sealing solution (an ethyl acetate solution of ethyl methacrylate and methyl acrylate, with a mass ratio of ethyl methacrylate to methyl acrylate of 34:66 and a concentration of 1wt%) to the surface of the desalinated iron artifact b. After the surface of iron artifact b has dried naturally, apply the sealing solution again and then allow iron artifact b to air dry naturally.

[0019] Example 3 S1: Use tools such as scalpels, needles, and brushes to remove the crust and relatively loose rust layer on the surface of the iron artifact c by picking, picking, peeling, and brushing. Then use a small grinder and dental scaler to clean the hard and stubborn rust on the surface of the iron artifact c. S2: After soaking the cleaned and rust-removed iron artifact c in deionized water, dry the surface of the iron artifact c. Repeat the soaking and drying steps 5 times to complete the desalination. S3: Use a brush to apply the corrosion inhibitor (a composite solution of sodium molybdate and benzotriazole, with the concentration of sodium molybdate in the corrosion inhibitor being 1.2wt% and the concentration of benzotriazole being 0.6wt%) to the surface of the desalinated iron artifact c. After the surface of the iron artifact c has dried naturally, apply the corrosion inhibitor again and then let the iron artifact c air dry naturally. S4: Use a brush to apply the sealing solution (an ethyl acetate solution of ethyl methacrylate and methyl acrylate, with a mass ratio of ethyl methacrylate to methyl acrylate of 34:66 and a concentration of 1wt%) to the surface of the desalinated iron artifact c. After the surface of iron artifact c has dried naturally, apply the sealing solution again and then allow iron artifact c to air dry naturally.

[0020] Example 4 A method for the restoration and preservation of iron artifacts includes the following steps: S1: Use tools such as scalpels, needles, and brushes to remove the crust and relatively loose rust layer on the surface of the iron artifact by picking, picking, peeling, and brushing. Then use a small grinder and dental scaler to clean the hard and stubborn rust on the surface of the iron artifact. S2: After soaking the cleaned and rust-removed iron artifact d in deionized water, dry the surface of the iron artifact d. Repeat the soaking and drying steps 5 times to complete the desalination. S3: Use a brush to apply the corrosion inhibitor (a composite solution of sodium molybdate and benzotriazole, with the concentration of sodium molybdate in the corrosion inhibitor being 1wt% and the concentration of benzotriazole being 0.5wt%) to the surface of the desalinated iron artifact d. After the surface of the iron artifact d has dried naturally, apply the corrosion inhibitor again and then let the iron artifact d air dry naturally. S4: Use a brush to apply the sealing solution (an ethyl acetate solution of ethyl methacrylate and methyl acrylate, with a mass ratio of ethyl methacrylate to methyl acrylate of 34:66 and a concentration of 1wt%) to the surface of the desalinated iron artifact d. After the surface of the iron artifact d has dried naturally, apply the sealing solution again and then allow the iron artifact d to air dry naturally.

[0021] Example 5 A method for the restoration and preservation of iron artifacts includes the following steps: S1: Use tools such as scalpels, needles, and brushes to remove the crust and relatively loose rust layer on the surface of the iron artifact e by picking, picking, peeling, and brushing. Then use a small grinder and dental scaler to clean the hard and stubborn rust on the surface of the iron artifact e. S2: After soaking the cleaned and rust-removed iron artifact e in deionized water, dry the surface of the iron artifact e. Repeat the soaking and drying steps 5 times to complete the desalination. S3: Use a brush to apply the corrosion inhibitor (a composite solution of sodium molybdate and benzotriazole, with the concentration of sodium molybdate in the corrosion inhibitor being 1wt% and the concentration of benzotriazole being 0.5wt%) to the surface of the desalinated iron artifact e. After the surface of the iron artifact e has dried naturally, apply the corrosion inhibitor again and then let the iron artifact e air dry naturally. S4: Use a brush to apply the sealing solution (an ethyl acetate solution of ethyl methacrylate and methyl acrylate, with a mass ratio of ethyl methacrylate to methyl acrylate of 34:66 and a concentration of 1wt%) to the surface of the desalinated iron artifact e. After the surface of the iron artifact e has dried naturally, apply the sealing solution again and then let the iron artifact e air dry naturally.

[0022] Example 6 A method for the restoration and preservation of iron artifacts includes the following steps: S1: Use tools such as scalpels, needles, and brushes to remove the crust and relatively loose rust layer on the surface of iron artifacts by picking, picking, peeling, and brushing. Then use a small grinder and dental scaler to clean the hard and stubborn rust on the surface of the iron artifacts. S2: After soaking the cleaned and rust-removed iron artifact f in deionized water, dry the surface of the iron artifact f. Repeat the soaking and drying steps 5 times to complete the desalination. S3: Use a brush to apply the corrosion inhibitor (a composite solution of sodium molybdate and benzotriazole, with the concentration of sodium molybdate in the corrosion inhibitor being 1wt% and the concentration of benzotriazole being 0.5wt%) to the surface of the desalinated iron artifact f. After the surface of the iron artifact f has dried naturally, apply the corrosion inhibitor again and then let the iron artifact f air dry naturally. S4: Use a brush to apply the sealing solution (an ethyl acetate solution of ethyl methacrylate and methyl acrylate, with a mass ratio of ethyl methacrylate to methyl acrylate of 34:66 and a concentration of 1wt%) to the surface of the desalinated iron artifact f. After the surface of the iron artifact f has dried naturally, apply the sealing solution again and then let the iron artifact f air dry naturally.

[0023] Experimental Example 1 XRD Analysis: XRD analysis was performed on the surface material of the iron artifact a from Example 1 before rust removal, after rust removal (i.e., before desalination), after desalination (i.e., before corrosion inhibition), after corrosion inhibition (i.e., before sealing), and after sealing. The results are as follows: Figures 1-5 As shown, by Figure 1 It is known that the surface composition of the iron samples before rust removal is mainly α-FeOOH, β-FeOOH, α-Fe2O3, and Fe3O4. Due to different structures, FeOOH can be divided into α-FeOOH, β-FeOOH, and γ-FeOOH. α-FeOOH is stalactite-like, with a dense structure, which can block harmful external factors and prevent moisture and oxygen from contacting the iron substrate, thus providing strong protection. Therefore, it is considered a harmless rust on the iron surface. The rust layer on the iron surface is usually a brown powder and does not need to be removed during protection. γ-FeOOH is highly reactive and tends to transform into the stable α-FeOOH or Fe3O4. γ-FeOOH has a cubic lattice and a loose structure, and cannot form a strong, stable, and dense protective film on the iron surface. It easily allows oxygen and moisture to penetrate, continuously generating rust under the action of electrochemical cycles, thickening the rust layer until it completely destroys the iron artifact. Therefore, it is an orange-yellow harmful rust and needs to be removed during protection. β-FeOOH is less dense than α-FeOOH and γ-FeOOH, mainly appearing as needles or rods, with a very loose structure. Its absorption capacity is comparable to that of γ-FeOOH. β-FeOOH, except for Cl in its crystal tunnel structure... - In addition, Cl is usually adsorbed on the crystal surface. - This provides highly favorable conditions for localized corrosion. The β-FeOOH crystal surface, besides adsorbing Cl... - In addition, it will also adsorb H + This process leads to partial protonation of the surface. The formation of β-FeOOH is accompanied by the formation of HCl. Some of the HCl enters the tunnel structure of β-FeOOH. When the HCl in the tunnel reaches saturation, the excess HCl is adsorbed on the surface of the β-FeOOH crystals, reducing the local dissolution of the rust layer and directly corroding the iron matrix. Therefore, β-FeOOH is a harmful rust on the surface of ironware, usually a brownish-yellow powder, and should be stabilized or removed during the storage of ironware.

[0024] Figure 2It can be seen that most of the harmful rust β-FeOOH was removed during the rust removal process of the iron sample, and the main surface components were α-FeOOH and Fe3O4; Figure 3 It can be seen that the surface composition of the iron sample after desalting is still α-FeOOH and Fe3O4, indicating that desalting did not cause significant changes to the surface of the iron sample. Figure 4 It can be seen that the surface composition of the iron sample after corrosion inhibition is α-FeOOH, Fe3O4, MoO3, and FeMoO4, with MoO4 being the most abundant component. 2- The presence of [something] promotes the transformation of γ-FeOOH to Fe2O3, while stable oxides are formed, and MoO4 is adsorbed on the rust layer surface. 2- It can also react with the corrosion products Fe dissolved from the anode. 2+ The reaction occurs in the rust layer, generating insoluble FeMoO4. The stable Fe2O3, MoO3, and FeMoO4 form a dense corrosion inhibitor film, which isolates the substrate from the external environment and inhibits further corrosion. Figure 5 It can be seen that the surface composition of the iron sample after sealing is α-FeOOH and Fe3O4, but the presence of MoO3 and FeMoO4 was not found. This may be because the content of MoO3 and FeMoO4 in the sample after sealing is too low to be detected.

[0025] Experimental Example 2 pH Testing of Corrosion Inhibitor and Sealing Solution: Glass slides were subjected to corrosion inhibition, sealing, and corrosion inhibition + sealing treatments, with pure water as a control group. The surface pH was tested under the same experimental conditions. First, the pH of the pure aqueous solution was measured to be 6.86, and the pH of the corrosion inhibitor solution was 6.93. This is because although the benzotriazole aqueous solution in the corrosion inhibitor is weakly acidic, the sodium molybdate solution is weakly alkaline. Excess sodium molybdate makes the combined solution nearly as weakly alkaline as pure water. The sealing agent is a copolymer of 34% ethyl methacrylate and 66% methyl acrylate directly dissolved in ethyl acetate solvent. For neutral ethyl acetate organic solvent, its pH cannot be accurately measured using a pH meter; therefore, the pH of the sealing agent solution was not directly measured. To determine the acidity or alkalinity of the surface microenvironment after the corrosion inhibitor and sealing agent films were formed, glass slides that would not react with the corrosion inhibitor and sealing agent were selected as the substrate. The slides were cleaned, and corrosion inhibition, sealing, and corrosion inhibition + sealing treatments were performed on their surfaces, respectively. The results are as follows: Figure 6Before etching and sealing, the pH of the slide was 6.85, which is relatively consistent with the pH of pure water (6.86). After etching treatment, the pH was 6.96, which is weakly alkaline, consistent with the theory that the etching inhibitor solution itself is weakly alkaline. After sealing treatment alone, the pH was 6.87, which is relatively consistent with the pH of pure water (6.86). The pH of the surface microenvironment after etching and sealing treatment was 7.01, which is higher than the pH of the surface microenvironment after etching or sealing treatment alone. The sealing agent itself does not contain alkaline components. When the sealing agent solution is applied, the residual alkaline etching inhibitor may partially dissolve in the solvent (ethyl acetate). When the solvent evaporates, capillary effect will cause the solute (alkaline substance) to migrate to the interface and deposit, resulting in a local increase in pH.

[0026] Experimental Example 3 pH Testing of Iron Surfaces: During the restoration and preservation of iron samples and artifacts, the pH of the surface microenvironment must be measured before and after each operational step, including before rust removal, after rust removal (i.e., before desalination), after desalination (i.e., before corrosion inhibition), after corrosion inhibition (i.e., before sealing), and after sealing. In Example 1, three areas of iron artifact a were selected for testing. 50 μL of pure water was pipetted onto the surface of each area, and the pH meter probe was fully immersed in contact with the area. Stable pH values ​​were read after 1 minute and recorded as pH1, pH2, and pH3. Similarly, the pH of the surface microenvironment of iron artifact a was measured before and after each operational step. The number of test areas can be selected according to the shape and size of the artifact, ensuring that the location of the test areas remains constant each time.

[0027] Table 1 shows the pH values ​​of the surface microenvironment in three areas during the restoration and conservation of iron artifact a, and plots them as a line graph. Figure 7 Before rust removal, the surface microenvironment of the iron artifacts was weakly acidic. Most iron artifacts unearthed, whether in coastal or inland areas, contain chlorides. In the burial environment, the main chloride corrosion product of iron artifacts is FeCl2, which is concentrated in the middle of the iron matrix and the rust layer, as well as in the pores and cracks of the rust layer, in the form of an acidic solution. After the iron artifacts are unearthed, FeCl2 is oxidized and hydrolyzed in the air to generate FeOOH and HCl, which causes the surface pH to decrease. XRD results also confirmed the presence of harmful rust β-FeOOH.

[0028] After rust removal, the pH of the microenvironment on the surface of the iron sample increased. As shown by the XRD results above, most of the harmful rust β-FeOOH was removed during the rust removal process. Acidic solutions concentrated in the rust layer, as well as acidic substances such as HCl adsorbed on the surface and internal tunnel structure of β-FeOOH crystals, were also removed. The iron surface mainly consists of harmless rust and iron matrix. Harmless rust Fe2O3 and Fe3O4 are stable oxides with inert chemical properties, almost insoluble or hydrolyzed in water, thus having little impact on pH. However, if Fe3O4 contains trace amounts of ferric hydroxide impurities, the surface microenvironment pH will become weakly alkaline after adding pure water. Adding pure water to the iron matrix surface may also form micro-batteries, generating Fe²⁺ in the anodic region and reducing O2 and H2O to OH⁻ in the cathode region, leading to a localized increase in pH.

[0029] The pH of the microenvironment on the surface of the iron samples was relatively lower after desalination compared to after rust removal. After rust removal, most of the harmful rust and Cl on the surface of the iron samples remained. - Cl has been removed, but it is still present inside the iron sample. - During the desalination process, the internal Cl... - (HCl) may be replaced by water or hydroxide ions, Cl - Released into free state Cl - That is, in the removal of Cl - At the same time H + It also removes salts in equal amounts; the desalting process is the conversion of β-FeOOH to α-FeOOH, during which HCl and H are released. + and Cl - Equal amounts enter and exit the β-FeOOH structure, so the pH of the microenvironment on the surface of the iron sample after desalination is relatively lower than that after rust removal, but the pH change is small and it does not show acidity.

[0030] The pH of the microenvironment on the surface of the iron sample was relatively higher after corrosion inhibition compared to after desalination. This is consistent with the pH change of the surface microenvironment after corrosion inhibition on the glass slide. Besides the fact that the corrosion inhibitor solution itself is weakly alkaline, the XRD results after corrosion inhibition of the iron sample indicate that an interfacial reaction occurred on the surface of the corrosion-inhibited layer, which may also have altered the pH. Benzotriazole (BTA) forms N-Fe bonds with Fe, adsorbing onto the substrate surface as a Fe-BTA complex, forming part of the corrosion inhibition film. The corrosion inhibitor can inhibit anodic dissolution and further inhibit Fe... 2+ The process of hydrolysis to produce acid may continue even after the cathode reaction, leading to the accumulation of OH⁻ and an increase in pH. At the same time, the hydrolysis of residual MoO₄²⁻ to produce OH⁻ can also cause an increase in pH.

[0031] The pH of the microenvironment on the surface of the iron sample was relatively higher after sealing than after corrosion inhibition, which is consistent with the pH change of the microenvironment on the surface of the glass slide after sealing. XRD results showed that no new substances were generated, indicating that the increase in pH was due to physical action. It is speculated that the alkaline corrosion inhibitor may have partially dissolved in the solvent (ethyl acetate), and the capillary effect caused the solute (alkaline substance) to migrate to the interface and deposit, resulting in a local increase in pH.

[0032] Table 1. pH of the surface microenvironment of iron artifacts (a)

[0033] Experiment Example 4 To further study the pH changes of the surface microenvironment of iron artifacts during the restoration and protection process, a pH5F flat pen pH meter was used to test and compare the pH of the surface microenvironment of 6 iron artifacts (a, b, c, d, e, f) in Examples 1 to 6 before rust removal (1), after rust removal (2), after desalination (3), after corrosion inhibition (4), and after sealing (5). The appropriate number of points were selected according to the shape and size of the artifacts and recorded as pH1, pH2, pH3, etc.

[0034] Depend on Figures 8-13 It can be seen that the pH of the surface microenvironment of the six iron artifacts and iron samples changed in a consistent manner after rust removal, desalination, corrosion inhibition, and sealing. Although there was a phenomenon that the pH of the surface microenvironment of the iron artifacts was lower after sealing than after corrosion inhibition, the pH of the surface microenvironment of the iron artifacts after sealing was always higher than that before rust removal, after rust removal, and after desalination, and was weakly alkaline.

[0035] In summary, after corrosion inhibition and sealing treatments, the surface microenvironment of iron artifacts exhibits a significantly increased pH level, becoming weakly alkaline. This protects iron artifacts from corrosion in acidic environments. Furthermore, in-situ monitoring of the pH changes in the surface microenvironment of iron artifacts using a pH meter reveals several possibilities. A significant decrease in pH, indicating increased acidity, could be due to the accumulation of acidic products (SO2, NO2, H2S, etc.) in the external atmosphere, damage, failure, or deterioration of the corrosion inhibition and sealing layers, or further corrosion leading to the generation and outward migration of acidic substances. Conversely, a significant increase in pH, indicating increased alkalinity, could cause alkaline corrosion. Regardless of the cause of a significant increase or decrease in the pH of the iron artifact's surface microenvironment, timely measures should be taken to strengthen its protection and prevent further damage.

[0036] Although specific embodiments of the present invention have been described in detail with reference to examples, they should not be construed as limiting the scope of protection of this patent. Various modifications and variations that can be made by those skilled in the art without inventive effort within the scope described in the claims are still within the scope of protection of this patent.

Claims

1. A method for the restoration and preservation of iron artifacts, characterized in that, Includes the following steps: S1: Clean and remove rust from the surface of iron artifacts; S2: Desalination treatment is carried out on iron artifacts after cleaning and rust removal; S3: Apply a corrosion inhibitor to the surface of the iron artifact after desalination treatment. After the surface of the iron artifact dries naturally, apply another layer of corrosion inhibitor. Then allow the iron artifact to air dry naturally. The corrosion inhibitor is a composite solution of molybdenum salt and benzotriazole. S4: Apply a sealing liquid to the surface of the iron artifact that has been air-dried. After the surface of the iron artifact has dried naturally, apply another layer of sealing liquid and then let the iron artifact air-dry naturally.

2. The method for protecting iron artifacts according to claim 1, characterized in that: The desalination process involves soaking the iron artifacts in deionized water and then drying the surface of the iron artifacts, with the soaking and drying steps being performed alternately.

3. The method for protecting iron artifacts according to claim 1, characterized in that: The molybdenum salt is sodium molybdate.

4. The method for protecting iron artifacts according to claim 3, characterized in that: The concentration of sodium molybdate in the corrosion inhibitor is 0.8~1.2wt%, and the concentration of benzotriazole is 0.4~0.6wt%.

5. The method for protecting iron artifacts according to claim 4, characterized in that: The concentration of sodium molybdate in the corrosion inhibitor is 1 wt%, and the concentration of benzotriazole is 0.5 wt%.

6. The method for protecting iron artifacts according to claim 1, characterized in that: The sealing solution is an ethyl acetate solution of ethyl methacrylate and methyl acrylate.

7. The method for protecting iron artifacts according to claim 6, characterized in that: The mass ratio of ethyl methacrylate to methyl acrylate in the sealing solution is 34:

66.

8. The method for protecting iron artifacts according to claim 6, characterized in that: The concentration of the sealing solution is 1 wt%.

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