Corrosion-resistant hastelloy-steel composite plate and preparation method thereof

Abstract

The invention belongs to the technical field of metal explosive welding, and particularly relates to a corrosion-resistant hastelloy-steel composite plate and a preparation method thereof.The corrosion-resistant hastelloy-steel composite plate structurally comprises a carbon steel base layer, a nickel-based composite transition layer and a hastelloy layer which are sequentially arranged from bottom to top; the contact surface of the carbon steel base layer and the nickel-based composite transition layer is subjected to laser micro-etching treatment; the nickel-based composite transition layer is composed of a nickel-chromium alloy matrix and a corrosion inhibitor nanocapsule; the corrosion inhibitor nanocapsule is prepared by loading a compound corrosion inhibitor of sodium molybdate and benzotriazole on a mesoporous silica carrier; the corrosion-resistant hastelloy-steel composite plate structure is manufactured through an explosive welding process. The nickel-based composite transition layer containing the mesoporous silica loaded compound corrosion inhibitor nanocapsule is arranged on the carbon steel base layer subjected to laser micro-etching treatment, and then the nickel-based composite transition layer and the hastelloy layer are subjected to explosive welding, so that the binding force is improved; and stable transition and interface corrosion inhibition of the carbon steel base layer and the hastelloy layer are achieved through the nickel-based composite transition layer, and the corrosion resistance of the composite board is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of metal explosive welding, and particularly relates to a corrosion-resistant hastelloy-steel composite plate and a preparation method thereof. BACKGROUND

[0002] Hastelloy has excellent corrosion resistance, especially in strong corrosive media such as hydrochloric acid, sulfuric acid, nitric acid and the like, and steel has good strength and economy, so the hastelloy-steel composite plate has a wide application prospect in the fields of chemical industry, petroleum, marine engineering and the like. At present, there are various methods for preparing the conventional hastelloy-steel composite plate, such as vacuum rolling, gas shielded welding and the like. However, the existing hastelloy-steel composite plate has some problems in the traditional welding process, such as insufficient interface bonding strength, limited corrosion resistance improvement and the like. In the disclosed literature patents, the performance of the composite plate is improved by simply performing surface treatment on the substrate and the hastelloy plate, but the structure design of the composite plate, the optimization of the interface layer and the welding method are relatively less studied, and it is difficult to meet the higher requirements of corrosion resistance and mechanical properties.

[0003] Therefore, it is urgent to explore and study a new structure design of the hastelloy-steel composite plate and a new preparation method for improving the corrosion resistance and mechanical properties of the hastelloy-steel composite plate. SUMMARY

[0004] To solve the above technical problems, the application provides a corrosion-resistant hastelloy-steel composite plate and a preparation method thereof. The nickel-based composite transition layer containing mesoporous silica loaded with compounded corrosion inhibitor nanocapsules is arranged on the carbon steel base layer treated by laser micro-etching, and then the hastelloy layer is prepared by explosive welding and low-temperature annealing, so as to improve the bonding force of the composite plate. The nickel-based composite transition layer realizes the stable transition and interface corrosion inhibition of the carbon steel base layer and the hastelloy layer, and relies on the excellent corrosion resistance of the hastelloy layer and the effect of the corrosion inhibitor nanocapsules in the nickel-based composite transition layer on inhibiting the corrosion of the composite plate to improve the corrosion resistance of the composite plate.

[0005] To achieve the above purposes, the application adopts the following technical solutions:

[0006] In a first aspect, the application provides a corrosion-resistant hastelloy-steel composite plate, which comprises a carbon steel base layer, a nickel-based composite transition layer and a hastelloy layer arranged in sequence from bottom to top. The surface of the carbon steel base layer in contact with the nickel-based composite transition layer is treated by laser micro-etching. The nickel-based composite transition layer is composed of a nickel-chromium alloy matrix and corrosion inhibitor nanocapsules. The corrosion inhibitor nanocapsules are uniformly dispersed in the nickel-chromium alloy matrix. The corrosion inhibitor nanocapsules are prepared by loading a compounded corrosion inhibitor of sodium molybdate and benzotriazole on a mesoporous silica carrier. The structure of the corrosion-resistant hastelloy-steel composite plate is prepared by an explosive welding process.

[0007] In the present application, laser micro-etching treatment forms micron-level grooves and protrusions on the surface of carbon steel, increasing the contact area with the nickel-based composite transition layer, while removing the oxide film layer on the surface of the carbon steel to provide a bonding site for welding and form a mechanical interlocking structure, thereby improving the bonding force. Subsequently, a nickel-based composite transition layer is prepared on the etched surface of the carbon steel, which incorporates mesoporous silica nanocapsules loaded with a compounded corrosion inhibitor (MoO4 2- and BTA). During explosive welding, the mesoporous silica nanocapsules are broken due to the action of shock wave pressure and instantaneous high temperature, releasing the compounded corrosion inhibitor. At the same time, the explosion drives the plastic flow of the hastelloy clad plate and the nickel-based composite transition layer through instantaneous high pressure, causing the Cr and Mo atoms in the hastelloy to diffuse with the Ni atoms in the transition layer to form a metallurgical bonding layer.

[0008] When the corrosion medium (such as Cl - ) in the environment penetrates into the clad plate, it will cause electrochemical corrosion and form a corrosion microcell. On the one hand, the MoO4 2- released by the corrosion inhibitor nanocapsules reacts with the Fe 2+ activated by laser etching on the surface of the carbon steel to form FeMoO4 attached to the concave-convex parts of the carbon steel micro-etching, forming a dense precipitate film that blocks the anodic dissolution of Fe (Fe→Fe 2+ + 2e - ), thereby inhibiting the corrosion of carbon steel; at the same time, Mo 6+ as a cathodic corrosion inhibitor, diffuses to the cathode area of the corrosion microcell and undergoes a reduction reaction, and the reduction product deposits on the cathode surface to form a dense protective film, increasing the cathode polarization and thus reducing the corrosion current. On the other hand, the synchronously released BTA molecules contain N atoms with lone pairs of electrons that form stable five-membered ring chelates (Ni-BTA) with oxidized Ni 2+ in the nickel-chromium alloy matrix, forming a hydrophobic organic film at the interface between the nickel-based composite transition layer and the hastelloy, which not only prevents the penetration of corrosion ions but also prevents the preferential corrosion of Cr and Mo.

[0009] Preferably, the hastelloy layer is any one of Hastelloy C-276, C-22 and B-3 alloys.

[0010] Preferably, the mass percentage of chromium in the nickel-chromium alloy matrix is 15%-25%, and the balance is nickel and unavoidable trace elements: the thickness of the nickel-based composite transition layer is 50-150 μm.

[0011] Preferably, the mass percentage of corrosion inhibitor nanocapsules in the nickel-based composite transition layer is 5%-20%.

[0012] Preferably, the incorporation amount of the mesoporous silica is 5%-15% of the total mass of the nickel-chromium alloy; the pore size of the mesoporous silica is 2-50nm, and the specific surface area is 500-1000m² / g; and the mass ratio of the sodium molybdate to the benzotriazole is 1:(0.5-2).

[0013] In a second aspect, the application provides a preparation method of a corrosion-resistant hastelloy-steel composite plate structure, comprising the following steps:

[0014] S1: performing laser micro-etching treatment on the surface of the carbon steel base layer in contact with the nickel-based composite transition layer;

[0015] S2: dissolving sodium molybdate and benzotriazole in a solvent in a certain proportion to obtain a compounded corrosion inhibitor, adding the compounded corrosion inhibitor into mesoporous silica by an equal-volume immersion method, drying to obtain corrosion inhibitor nanocapsules; and mixing the corrosion inhibitor nanocapsules with nickel-chromium alloy powder to obtain composite spraying powder;

[0016] S3: depositing the composite spraying powder on the surface of the carbon steel base layer treated in S1 by a plasma spraying process to form a nickel-based composite transition layer;

[0017] S4: covering a hastelloy plate as a cladding plate on the surface of the nickel-based composite transition layer, laying explosive on the surface of the cladding plate, and realizing explosion welding of each layer by detonation through a detonator to obtain a corrosion-resistant hastelloy-steel composite plate;

[0018] S5: performing surface cleaning and low-temperature annealing stress relief on the corrosion-resistant hastelloy-steel composite plate.

[0019] Preferably, the laser power in the laser micro-etching treatment in S1 is 100-300W, the scanning speed is 50-200mm / s, and the pulse frequency is 20-50kHz.

[0020] Preferably, the solvent in S2 comprises at least one of anhydrous ethanol, acetone and ethyl acetate; the immersion temperature is 25-50℃, and the immersion time is 12-24h; and the drying temperature is 40-60℃, and the drying time is 6-12h.

[0021] Preferably, the detonation velocity of the explosive in S4 is 2000-4000m / s, and the thickness of the explosive is 5-20mm.

[0022] Preferably, the annealing temperature in S5 is 200-300℃, and the holding time is 1-2h.

[0023] Compared with the prior art, the application has the following beneficial effects:

[0024] The application provides a kind of corrosion-resistant hastelloy-steel composite plate, first, laser micro-etching treatment makes carbon steel surface micron-level groove and protrusion, increase the contact area with nickel-based composite transition layer, at the same time, carbon steel surface oxide film layer can be removed, to provide bonding site for welding, form mechanical interlocking structure, to improve the bonding force. Subsequently, nickel-based composite transition layer is prepared on the etched carbon steel surface, the transition layer is incorporated with mesoporous silica nanocapsules loaded with compound corrosion inhibitor (MoO4 2- And BTA), during explosive welding, due to the effect of shock wave pressure and instantaneous high temperature, the mesoporous silica nanocapsules are broken, releasing the compound corrosion inhibitor. At the same time, the explosion drives the hastelloy composite plate and the nickel-based composite transition layer to occur plastic rheology by instantaneous high pressure, so that the Cr and Mo atoms in the hastelloy diffuse with the Ni atoms in the transition layer to form a metallurgical bonding layer.

[0025] When the corrosion medium (such as Cl - ) in the environment penetrates into the composite plate, it will cause electrochemical corrosion and form a corrosion microcell. On the one hand, MoO4 2- released by the corrosion inhibitor nanocapsule reacts with Fe 2+ activated by laser etching on the surface of carbon steel to form FeMoO4 attached to the concave-convex parts of carbon steel micro-etching, forming a dense precipitate film to block the anodic dissolution of Fe (Fe→Fe 2+ +2e - ), thereby inhibiting the corrosion of carbon steel; at the same time, Mo 6+ acts as a cathodic corrosion inhibitor, diffuses to the cathode area of the corrosion microcell and undergoes a reduction reaction, and the reduction product deposits on the cathode surface to form a dense protective film, thereby increasing the cathode polarization and reducing the corrosion current. On the other hand, the N atom with a lone pair of electrons in the synchronously released BTA molecule forms a stable five-membered ring chelate (Ni-BTA) with the oxidized Ni 2+ in the nickel-chromium alloy matrix, forming a hydrophobic organic film at the interface between the nickel-based composite transition layer and the hastelloy, which not only prevents the penetration of corrosion ions, but also prevents the preferential corrosion of Cr and Mo. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a flowchart of a method for preparing a corrosion-resistant hastelloy-steel composite plate;

[0027] Figure 2 is a SEM image of the rough surface of the carbon steel base layer after laser micro-etching treatment;

[0028] Figure 3 is an electrochemical corrosion polarization curve graph of Example 2 and Comparative Examples 1-4. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the embodiments of this application. Obviously, the embodiments described below are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0030] In this application, the terminology used is for the purpose of describing particular embodiments only and is not intended to be limiting of this application.

[0031] The singular forms “for,” “or,” “a,” “any,” and “the” used in this application are intended to include the plural forms unless the context clearly indicates otherwise.

[0032] Furthermore, the terms "first" and "second" appearing in this application are for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0033] The following will describe in detail, with reference to specific embodiments, a method for preparing a corrosion-resistant Hastelloy-steel composite plate provided in this application.

[0034] Example 1

[0035] like Figure 1 The method for preparing a corrosion-resistant Hastelloy-steel composite plate includes the following steps:

[0036] S1: Laser micro-etching treatment with a power of 100W, a scanning speed of 50mm / s, and a pulse frequency of 20kHz is performed on the surface where the carbon steel base layer and the nickel-based composite transition layer are in contact.

[0037] S2: Sodium molybdate and benzotriazole were dissolved in anhydrous ethanol at a mass ratio of 1:0.5 to obtain a compound corrosion inhibitor. At 25°C, the compound corrosion inhibitor was added to 5% (by mass) of mesoporous silica (with a pore size of 2 nm and a specific surface area of ​​500 m² / g) of the total mass of the nickel-chromium alloy using an equal-volume impregnation method, and impregnated for 12 h. Subsequently, it was dried at 40°C for 6 h to obtain corrosion inhibitor nanocapsules. 5% (by mass) of the corrosion inhibitor nanocapsules of the total mass of the nickel-based composite transition layer were mixed with nickel-chromium alloy powder (15% chromium by mass, with the remainder being nickel and trace elements) to obtain a composite spray powder.

[0038] S3: A 50μm thick nickel-based composite transition layer is formed by depositing composite powder onto the surface of a carbon steel substrate treated with S1 using a plasma spraying process.

[0039] S4: C-276 Hastelloy plate is covered as a clad plate on the surface of the nickel-based composite transition layer, and an explosive with a detonation velocity of 2000 m / s and a thickness of 5 mm is laid on the surface of the clad plate, and explosion welding is realized by detonation of a detonator to obtain a corrosion-resistant Hastelloy-steel clad plate.

[0040] S5: The surface of the corrosion-resistant Hastelloy-steel clad plate is cleaned, and low-temperature annealing is performed at 200°C for 1h to eliminate stress.

[0041] Example 2

[0042] As shown in a method for preparing a corrosion-resistant Hastelloy-steel clad plate, comprising the following steps: Figure 1

[0043] S1: The surface of the carbon steel base layer in contact with the nickel-based composite transition layer is subjected to laser micro-etching treatment with a power of 200W, a scanning speed of 130mm / s, and a pulse frequency of 30kHz.

[0044] S2: Sodium molybdate and benzotriazole are dissolved in acetone at a mass ratio of 1:1 to obtain a compounded corrosion inhibitor. Under the condition of 35°C, the compounded corrosion inhibitor is added to 10% of the total mass of the nickel-chromium alloy mesoporous silica with a pore size of 20nm and a specific surface area of 800m 2 / g by equal-volume immersion method, and is immersed for 18h. Subsequently, it is dried at 50°C for 10h to obtain corrosion inhibitor nanocapsules. The corrosion inhibitor nanocapsules account for 15% of the total mass of the nickel-based composite transition layer, and are mixed with the nickel-chromium alloy powder to obtain a composite spraying powder. The mass percentage of chromium in the nickel-chromium alloy powder is 20%, and the balance is nickel and trace elements.

[0045] S3: The composite spraying powder is deposited on the surface of the carbon steel base layer treated by S1 by using plasma spraying process to form a nickel-based composite transition layer with a thickness of 100μm.

[0046] S4: C-22 Hastelloy plate is covered as a clad plate on the surface of the nickel-based composite transition layer, and an explosive with a detonation velocity of 3000 m / s and a thickness of 15 mm is laid on the surface of the clad plate, and explosion welding is realized by detonation of a detonator to obtain a corrosion-resistant Hastelloy-steel clad plate.

[0047] S5: The surface of the corrosion-resistant Hastelloy-steel clad plate is cleaned, and low-temperature annealing is performed at 250°C for 1.5h to eliminate stress.

[0048] Example 3

[0049] As shown in a method for preparing a corrosion-resistant Hastelloy-steel clad plate, comprising the following steps: Figure 1

[0050] ​​S1: The surface of the carbon steel base layer in contact with the nickel-based composite transition layer is subjected to laser micro-etching treatment with a power of 300 W, a scanning speed of 200 mm / s, and a pulse frequency of 50 kHz.

[0051] S2: A compound corrosion inhibitor is obtained by dissolving sodium molybdate and benzotriazole in ethyl acetate at a mass ratio of 1:2. The compound corrosion inhibitor is added to 15% of the total mass of mesoporous silica in the nickel-chromium alloy by the equal-volume immersion method at 50°C, the mesoporous silica has a pore size of 50 nm and a specific surface area of 1000 m² / g, and the immersion lasts for 24 h. Subsequently, the mesoporous silica is dried at 60°C for 12 h to obtain corrosion inhibitor nanocapsules. The corrosion inhibitor nanocapsules are mixed with 20% of the total mass of the nickel-chromium alloy powder in the nickel-based composite transition layer to obtain a composite spraying powder, wherein the mass percentage of chromium in the nickel-chromium alloy powder is 25%, and the balance is nickel and trace elements.

[0052] S3: The composite spraying powder is deposited on the surface of the carbon steel base layer treated by S1 by plasma spraying to form a nickel-based composite transition layer with a thickness of 150 μm.

[0053] S4: A B-3 Hastelloy plate is used as a cladding plate to cover the surface of the nickel-based composite transition layer, and an explosive with a detonation velocity of 4000 m / s and a thickness of 20 mm is laid on the surface of the cladding plate to realize explosive welding by detonation of a detonator to obtain a corrosion-resistant Hastelloy-steel composite plate.

[0054] S5: The composite plate is subjected to surface cleaning and low-temperature annealing at 300°C for 2 h to eliminate stress.

[0055] Comparative Example 1

[0056] A method for preparing a corrosion-resistant Hastelloy-steel composite plate, which is different from Example 2 in that there is no laser micro-etching in the step.

[0057] Comparative Example 2

[0058] A method for preparing a corrosion-resistant Hastelloy-steel composite plate, which is different from Example 2 in that there is no mesoporous silica loading in the step.

[0059] Comparative Example 3

[0060] A method for preparing a corrosion-resistant Hastelloy-steel composite plate, which is different from Example 2 in that the nickel-based composite transition layer is a nickel-chromium alloy matrix in the step.

[0061] Comparative Example 4

[0062] A method for preparing a corrosion-resistant Hastelloy-steel composite plate, which is different from Example 2 in that the corrosion inhibitor nanocapsules are prepared by loading sodium molybdate on a mesoporous silica carrier in the step.

[0063] Performance test:

[0064] (1) Shear strength test: The composite board samples prepared in Examples 1-3 and Comparative Examples 1-4 were subjected to single lap shear test using a universal testing machine. The composite board samples were processed into a size of 50 mm x 20 mm. During the test, a constant rate of 1 mm / min was applied to shear force until the composite board sample failed, and the maximum load was recorded. The shear strength (τ) was calculated according to the formula: τ = Fmax / A, where Fmax is the maximum load, and A is the lap area.

[0065] (2) Corrosion resistance test: The composite board samples prepared in Examples 1-3 and Comparative Examples 1-4 were immersed in boiling hydrochloric acid solution. The composite board samples were completely immersed in boiling (about 110°C) hydrochloric acid solution with a concentration of 20wt%. The samples were periodically taken out and dried for weighing. The weight loss of the sample before and after the test was measured using a precision balance. The corrosion rate (CR) was calculated according to the formula: CR = (K x ΔW) / (S x T x p), where K is a constant, ΔW is the weight loss (g), S is the area (cm 2 ), T is the time (h), and p is the material density (g / cm 3 ). The corrosion depth per unit time was calculated by the weight loss method.

[0066] (3) Salt spray test: The composite board samples prepared in Examples 1-3 and Comparative Examples 1-4 were placed in a salt spray test chamber. The spray solution was a 5% mass concentration of NaCl solution, with a pH value of 6.5-7.2 and a temperature of 35°C ± 1°C. After 500h and 1000h, the surface rust condition was observed and the rust area ratio was calculated to evaluate the surface corrosion resistance of the material.

[0067] (4) Electrochemical corrosion test: The composite board samples prepared in Examples 1-3 and Comparative Examples 1-4 were subjected to a three-electrode system (working electrode: sample, reference electrode: saturated calomel electrode, auxiliary electrode: platinum plate) in the same boiling hydrochloric acid solution as the corrosion resistance test. The polarization curve and electrochemical impedance spectrum were measured.

[0068] The performance test results are shown in Table 1.

[0069] Table 1 Performance test data of Examples 1-3 and Comparative Examples 1-4

[0070]

[0071] According to Table 1, in the shear strength test, the shear strength of Examples 1-3 (245-268 MPa) was higher than that of Comparative Examples 1-4 (182-221 MPa). This is attributed to the mechanical interlocking effect after laser etching and the synergistic effect of the transition layer. All examples involved laser micro-etching of the carbon steel substrate, resulting in a micron-level rough surface structure on the carbon steel after etching. Figure 2 As shown, this not only increases the contact area between the nickel-based composite transition layer and the carbon steel substrate, but also hinders relative sliding between layers through mechanical interlocking, thus enhancing interfacial bonding. In Comparative Example 1, due to the absence of laser etching, the carbon steel surface is smooth, and the transition layer relies solely on physical adsorption for bonding, resulting in a shear strength of only 182 MPa, directly demonstrating that laser etching is key to interfacial strengthening. Furthermore, in the examples, the corrosion inhibitor nanocapsules loaded with mesoporous silica in the transition layer are uniformly dispersed within the nickel-chromium alloy matrix, avoiding interfacial defects caused by component agglomeration. In contrast, Comparative Example 2, lacking mesoporous silica loading, suffers from micropores due to corrosion inhibitor agglomeration, resulting in lower shear strength compared to the examples. Comparative Examples 3 and 4, with their pure nickel-chromium transition layers lacking the filling effect of corrosion inhibitor capsules, also exhibit lower shear strengths than the examples.

[0072] In an environment of 20wt% boiling hydrochloric acid (approximately 110°C), the corrosion rates of Examples 1-3 (0.05-0.08 mm / a) were significantly lower than those of the comparative example (0.15-0.23 mm / a). This advantage stems from the corrosion resistance mechanism of the composite corrosion inhibitor supported on mesoporous silica. In these examples, mesoporous silica (pore size 2-50 nm, specific surface area 500-1000 m² / g) serves as a carrier, controlling the release rates of sodium molybdate (anodic corrosion inhibitor) and benzotriazole (cathode corrosion inhibitor). Sodium molybdate forms an oxide film on the carbon steel surface, blocking anodic dissolution, while benzotriazole inhibits hydrogen evolution at the cathode through adsorption. Together, they construct a stable passivation film, thereby reducing the corrosion reaction rate. Comparative Example 2, lacking mesoporous silica loading, showed rapid dissolution of the corrosion inhibitor in boiling hydrochloric acid, becoming ineffective within 12 hours, with a corrosion rate of 0.19 mm / a. Comparative Example 4 (single sodium molybdate corrosion inhibitor) could only inhibit the anodic reaction, while hydrogen evolution continued at the cathode, with a corrosion rate of 0.15 mm / a. Comparative Example 3 (without corrosion inhibitor) relied solely on the physical isolation of the nickel-chromium transition layer, allowing hydrochloric acid to easily penetrate the carbon steel through micro-gap, resulting in a corrosion rate of 0.21 mm / a.

[0073] In salt spray tests, during 500h and 1000h salt spray tests (5% NaCl solution, 35℃±1℃), the rust area percentage (0.1%-0.8%) in Examples 1-3 was lower than that in the comparative example. The key difference lies in the fact that the laser etching in the examples created a mechanically interlocking structure between the carbon steel and the transition layer interface, reducing the channels for salt spray penetration by more than 40% and preventing interface corrosion due to Cl. - Electrochemical corrosion induced by erosion; simultaneously, corrosion inhibitors are slowly released from the transition layer, forming an anti-corrosion film at the interface, further preventing Cl- corrosion. -The carbon steel was damaged. Comparative Example 1 had no laser etching, and micro gaps existed in the interface, so salt spray easily penetrated and caused rust, and the rust area accounted for 8.2% after 1000h; Comparative Example 3 had no corrosion inhibitor interface, and had no additional corrosion protection, and the rust area accounted for 3.1% after 500h.

[0074] The electrochemical corrosion performance test data of Examples 1-3 and Comparative Examples 1-4 are shown in Table 2.

[0075] Table 2: Electrochemical corrosion performance test data of Examples 1-3 and Comparative Examples 1-4

[0076]

[0077] From the analysis of the polarization curve graphs in Table 2 and Figure 3 , the corrosion current density of Examples 1-3 was only 0.15-0.21 μA / cm 2 , which was better than 0.58-0.89 μA / cm 2 of the comparative group, which was due to the synergistic effect of laser micro-etching and mesoporous silica loaded complex corrosion inhibitor. Laser etching formed a mechanical interlocking interface between the carbon steel base layer and the nickel-based composite transition layer, reducing the penetration channel of corrosion medium; after the compounding of sodium molybdate (anodic corrosion inhibitor) and benzotriazole (cathodic corrosion inhibitor) loaded by mesoporous silica, the corrosion inhibitor was released slowly, and a dense passivation film was formed at the interface, which inhibited the anode and cathode of the corrosion electrochemical reaction. Comparative Example 1 had many interface gaps due to no laser etching, and the corrosion current was as high as 0.89 μA / cm 2 ; Comparative Example 2 had no mesoporous silica loading, which caused the corrosion inhibitor to be easily lost, Comparative Example 3 had no corrosion inhibitor and only relied on physical isolation, and Comparative Example 4 had a single corrosion inhibitor that lacked synergistic effect, all of which caused the corrosion current to increase significantly.

[0078] The charge transfer resistance reflects the resistance of charge transfer on the electrode surface in the corrosion reaction, and the larger the value, the lower the corrosion rate, which is opposite to the trend of change of corrosion current density. The charge transfer resistance of Examples 1-3 was 285-352 kΩ·cm², which was higher than 92-168 kΩ·cm² of the comparative group, which was due to the laser etching strengthening the interface bonding and the mesoporous silica loading complex corrosion inhibitor continuously forming a dense passivation film, which increased the charge transfer resistance; Comparative Example 1 had many interface gaps due to no laser etching, which caused the charge to be easily transferred, and the charge transfer resistance was only 92 kΩ·cm². Although Comparative Example 4 used a single corrosion inhibitor to increase the charge transfer resistance to 168 kΩ·cm², it was still much lower than the examples, further confirming the synergistic effect of the complex corrosion inhibitor and the mesoporous loading.

[0079] The above results show and describe the basic principles and main features of the present application and the advantages of the present application.

[0080] Those skilled in the art should understand that the present application is not limited by the above-mentioned embodiments, the above-mentioned embodiments and descriptions in the specification are only to illustrate the principles of the present application, and various changes and improvements can be made to the present application without departing from the spirit and scope of the present application, and these changes and improvements all fall within the scope of the claimed present application. The scope of protection of the present application is defined by the equivalents of the appended claims.

Claims

1. A corrosion-resistant Hastelloy-steel composite plate, characterized in that, The structure comprises, from bottom to top, a carbon steel base layer, a nickel-based composite transition layer, and a Hastelloy layer; the surfaces of the carbon steel base layer and the nickel-based composite transition layer in contact are treated with laser micro-etching; the nickel-based composite transition layer is composed of a nickel-chromium alloy matrix and corrosion inhibitor nanocapsules; the corrosion inhibitor nanocapsules are uniformly dispersed in the nickel-chromium alloy matrix; the corrosion inhibitor nanocapsules are prepared by loading a compound corrosion inhibitor of sodium molybdate and benzotriazole onto a mesoporous silica carrier; the corrosion-resistant Hastelloy-steel composite plate structure is prepared by explosive welding.

2. The corrosion-resistant Hastelloy-steel composite plate according to claim 1, characterized in that, The Hastelloy alloy layer is any one of Hastelloy C-276, C-22 and B-3 alloys.

3. The corrosion-resistant Hastelloy-steel composite plate according to claim 1, characterized in that, The mass percentage of chromium in the nickel-chromium alloy matrix is ​​15%-25%; the thickness of the nickel-based composite transition layer is 50-150 μm.

4. The corrosion-resistant Hastelloy-steel composite plate according to claim 1, characterized in that, The corrosion inhibitor nanocapsules in the nickel-based composite transition layer have a mass percentage of 5%-20%.

5. The corrosion-resistant Hastelloy-steel composite plate according to claim 1, characterized in that, The amount of mesoporous silica incorporated is 5%-15% of the total mass of the nickel-chromium alloy; the pore size of the mesoporous silica is 2-50 nm, and the specific surface area is 500-1000 m² / g; the mass ratio of sodium molybdate to benzotriazole is 1:(0.5-2).

6. A method for preparing a corrosion-resistant Hastelloy-steel composite plate according to any one of claims 1-5, characterized in that, Includes the following steps: S1: Laser micro-etching is performed on the surface where the carbon steel base layer and the nickel-based composite transition layer are in contact. S2: Dissolve sodium molybdate and benzotriazole in a solvent in a certain proportion to obtain a compound corrosion inhibitor. Add the compound corrosion inhibitor to mesoporous silica using an equal volume impregnation method and dry to obtain corrosion inhibitor nanocapsules. Mix the corrosion inhibitor nanocapsules with nickel-chromium alloy powder to obtain a composite spray powder. S3: The composite powder is deposited on the surface of the carbon steel base layer treated by S1 using a plasma spraying process to form a nickel-based composite transition layer. S4: Hastelloy plate is used as a cladding plate to cover the surface of nickel-based composite transition layer. Explosives are laid on the surface of the cladding plate and detonated by detonators to achieve explosive welding composite of each layer, thus obtaining a corrosion-resistant Hastelloy-steel composite plate. S5: Perform surface cleaning and annealing on the corrosion-resistant Hastelloy-steel composite plate.

7. The method for preparing a corrosion-resistant Hastelloy-steel composite plate according to claim 6, characterized in that, The laser power in the laser micro-etching process described in S1 is 100-300W, the scanning speed is 50-200mm / s, and the pulse frequency is 20-50kHz.

8. The method for preparing a corrosion-resistant Hastelloy-steel composite plate according to claim 6, characterized in that, The solvent in S2 includes at least one of anhydrous ethanol, acetone and ethyl acetate; the impregnation temperature is 25-50℃ and the time is 12-24h; the drying temperature is 40-60℃ and the drying time is 6-12h.

9. The method for preparing a corrosion-resistant Hastelloy-steel composite plate according to claim 6, characterized in that, The explosive described in S4 has a detonation velocity of 2000-4000 m / s and an explosive thickness of 5-20 mm.

10. The method for preparing a corrosion-resistant Hastelloy-steel composite plate according to claim 6, characterized in that, The annealing temperature described in S5 is 200-300℃, and the holding time is 1-2 hours.

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