Self-release composite corrosion inhibitor and preparation method thereof
The self-releasing composite corrosion inhibitor, which combines inorganic composite rust inhibitors with carbon nanotubes, solves the problem of steel corrosion in marine environments and achieves a highly efficient multi-layered protective effect.
Patent Information
- Application Number
- CN202610098738.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-26
- Publication Date
- 2026-05-15
AI Technical Summary
Existing inorganic rust inhibitors and organic corrosion inhibitors are difficult to provide long-term protection in marine environments and cannot effectively prevent steel reinforcement corrosion, especially in high-chloride salt environments.
An inorganic composite corrosion inhibitor is combined with carbon nanotubes to form a self-releasing framework structure. This structure is then combined with the organic corrosion inhibitor ethylenediaminetetramethylenephosphonic acid via a hydrothermal reaction to form a stable protective film, enabling rapid diffusion of inorganic ions and effective adsorption of the organic corrosion inhibitor.
In a high chloride ion environment, it effectively isolates steel bars from the corrosive environment, forms an oxide film layer to prevent rust, has high corrosion inhibition efficiency and few limitations in application.
Smart Images
Figure CN122039063A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the technical field of corrosion inhibitors for reinforced concrete, specifically a self-releasing composite corrosion inhibitor and its preparation method. Background Technology
[0002] Reinforced concrete structures are indispensable supporting components in marine engineering; however, during their long-term service, the Cl- in the marine environment... - Ions gradually diffuse into the steel-concrete interface, causing the passivation film on the steel surface to rupture and inducing steel corrosion. Their volume expansion effect leads to cracking and spalling of the concrete cover, resulting in the failure and deterioration of the reinforced concrete structure. Currently, inorganic corrosion inhibitors and organic corrosion inhibitors are commonly used to slow down the corrosion rate of reinforced concrete and extend its service life. However, these methods still suffer from limitations such as single function and limited corrosion inhibition effect, making it difficult to achieve long-term protection in high-chloride environments like those in the marine environment.
[0003] Therefore, in order to achieve rapid diffusion of inorganic rust inhibitor ions and effective support of organic corrosion inhibitors, designing a synergistic anti-corrosion skeleton structure of inorganic rust inhibitor ions and organic corrosion inhibitors is of great significance for the durability of reinforced concrete in marine environments. Summary of the Invention
[0004] To address the aforementioned technical problems, this invention provides a method for preparing a self-releasing composite corrosion inhibitor, comprising the following steps: S1. An inorganic composite rust inhibitor solution is prepared by mixing sodium dihydrogen phosphate and disodium hydrogen phosphate, wherein the mass ratio of sodium dihydrogen phosphate to disodium hydrogen phosphate in the inorganic composite rust inhibitor solution is (1:3) to (3:1), and the concentration of phosphorus in the inorganic composite rust inhibitor is 22wt% to 25wt%. S2. Disperse carbon nanotubes in the inorganic composite rust inhibitor solution to obtain a self-releasing framework solution. The mass ratio of the carbon nanotubes to the inorganic composite rust inhibitor solution is 2:1. The content of carbon nanotubes with a length greater than or equal to 50 nm is greater than or equal to 60 vol%. S3. Ethylenediaminetetramethylenephosphonic acid and the self-releasing skeleton solution are mixed at a mass ratio of (1:3) to (3:1) and subjected to a hydrothermal reaction to obtain a self-releasing composite corrosion inhibitor.
[0005] Furthermore, the mass ratio of sodium dihydrogen phosphate to disodium hydrogen phosphate in the inorganic composite rust inhibitor solution is any one of 1:1, 1:2, 1:3, 2:1, 2:3, 3:1, 3:2 or a range between the two. Furthermore, ethylenediaminetetramethylenephosphonic acid and the self-releasing skeleton solution are mixed in a mass ratio of any one or a range between two of 1:1, 1:2, 1:3, 2:1, 2:3, 3:1, and 3:2.
[0006] In step S2, the carbon nanotubes are prepared by chemical vapor deposition on a metal catalyst using methane as the carbon source.
[0007] In step S2, the chemical vapor deposition reaction temperature is 700~900℃, the reaction pressure is 1 atm, the reaction time is 1~5h, the methane flow rate is 100~300 sccm, and the metal catalyst is a cobalt-molybdenum alloy. Furthermore, the reaction temperature of the chemical vapor deposition is any one of 700°C, 800°C, and 900°C, or a range between two of them. Furthermore, the reaction time for the chemical vapor deposition is any one of 1h, 2h, 3h, 4h, 5h, or a range between two of them.
[0008] Specifically, step S2 involves dispersing carbon nanotubes in the inorganic composite rust inhibitor solution and subjecting them to ultrasonic vibration to obtain a self-releasing skeleton solution. The ultrasonic vibration power is 200-300W, the frequency is 40-50Hz, the time is 1-5h, and the temperature is 20-25℃.
[0009] In step S3, the hydrothermal reaction is carried out at a temperature of 100°C for 12 hours and at a pressure of 1 MPa.
[0010] To address the aforementioned technical problems, the present invention also provides a self-releasing composite corrosion inhibitor, which is prepared by the above-described preparation method.
[0011] The corrosion inhibitor has a release rate of 45% or greater after being soaked in a 3.5 wt% NaCl solution for 24 hours.
[0012] Among them, a solution containing 3.5wt% NaCl was prepared and mixed with the self-releasing composite corrosion inhibitor at a mass ratio of 9:1. After immersing HBP300 steel bars in the solution for 30 days, there was no obvious rust, and the pitting potential was greater than or equal to 400mV.
[0013] This invention combines inorganic and organic components. Inorganic ions can form precipitates on the surface of steel bars, isolating them from the service environment and preventing corrosion. The organic components have strong adsorption properties and can form a stable protective film on the surface of the steel bars, which is effective against high-Cl environments such as marine environments. - Multiple protections for steel bars in ion service environments; the corrosion inhibitor of this invention, through a carbon nanotube support structure, can achieve rapid diffusion of the corrosion inhibitor, resulting in high corrosion inhibition efficiency and minimal limitations in application. Attached Figure Description
[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.
[0015] Figure 1 The images show the morphology of the reinforcing bars after corrosion inhibition tests in Example 1 and Comparative Example 1. Figure 2 The images show the potentiodynamic polarization curves obtained from corrosion inhibition tests on reinforcing bars in some embodiments and comparative examples.
[0016] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation
[0017] The technical solutions described below in conjunction with the embodiments will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0018] This invention provides a method for preparing a self-releasing composite corrosion inhibitor, comprising the following steps: S1. An inorganic composite rust inhibitor solution is prepared by mixing sodium dihydrogen phosphate and disodium hydrogen phosphate, wherein the mass ratio of sodium dihydrogen phosphate to disodium hydrogen phosphate in the inorganic composite rust inhibitor solution is (1:3) to (3:1), and the concentration of phosphorus in the inorganic composite rust inhibitor is 22wt% to 25wt%. The inventors of this invention have discovered that mixing sodium dihydrogen phosphate and disodium hydrogen phosphate in a specific ratio can achieve a synergistic interaction of inorganic composite rust inhibitors and ensure the environment required for effective surface film growth.
[0019] S2. Carbon nanotubes are dispersed in the inorganic composite rust inhibitor solution to obtain a self-releasing skeleton solution, wherein the mass ratio of carbon nanotubes to the inorganic composite rust inhibitor solution is 2:1; S3. Ethylenediaminetetramethylenephosphonic acid and the self-releasing skeleton solution are mixed at a mass ratio of (1:3) to (3:1) and subjected to a hydrothermal reaction to obtain a self-releasing composite corrosion inhibitor.
[0020] The inventors of this invention discovered that by using ethylenediaminetetramethylenephosphonic acid as an organic corrosion inhibitor and mixing it with a self-releasing skeleton solution in a specific ratio, the organic corrosion inhibitor can be effectively attached to the surface of the self-releasing skeleton. If the ratio is too small, it is difficult to meet the slow-release effect, and if the ratio is too large, it will cause the skeleton to collapse.
[0021] Due to its three-dimensional support framework, the carbon nanotube structure provides diffusion channels for inorganic ion corrosion inhibitors, enabling rapid diffusion and formation of an oxide film. Simultaneously, the multi-point support structure of carbon nanotubes effectively provides support sites for organic corrosion inhibitors, allowing them to form a film on the steel reinforcement surface through adsorption, thus blocking contact between the corrosive medium and the steel reinforcement and meeting the requirements of complex marine corrosion environments such as high-chlorine environments.
[0022] The inventors of this invention discovered through research that using carbon nanotubes with a length greater than or equal to 50 nm and a content exceeding 60 vol% significantly improves the corrosion inhibition rate of the corrosion inhibitor in this invention. Therefore, the inventors of this invention chose a chemical vapor deposition method to prepare carbon nanotubes with the length meeting the above requirements.
[0023] This invention combines inorganic composite corrosion inhibitors (sodium dihydrogen phosphate and disodium hydrogen phosphate) with carbon nanotubes to achieve rapid diffusion of inorganic ions within the carbon nanotubes. When applied as a corrosion inhibitor to the surface of marine steel reinforcement, it forms an oxide layer on the steel reinforcement surface, effectively isolating the steel reinforcement from the corrosive environment. Subsequently, through a hydrothermal reaction, organic ethylenediaminetetramethylenephosphonic acid is combined with the framework structure to achieve effective adsorption and support of the organic corrosion inhibitor. In a high chloride ion corrosive environment, the organic corrosion inhibitor will adsorb at the corrosion site, effectively preventing further corrosion.
[0024] In this embodiment of the invention, the steel bar used for corrosion inhibition testing was HPB300 steel bar. A solution containing 3.5wt% NaCl was prepared and mixed with the self-releasing composite corrosion inhibitor of the present invention at a mass ratio of 9:1. After immersing the HBP300 steel bar in the solution for 30 days, there was no obvious corrosion, and its pitting potential was measured to be greater than or equal to 400mV.
[0025] Example 1 A method for preparing a self-releasing composite corrosion inhibitor includes the following steps: S1. An inorganic composite rust inhibitor solution is prepared by mixing sodium dihydrogen phosphate and disodium hydrogen phosphate, wherein the mass ratio of sodium dihydrogen phosphate to disodium hydrogen phosphate in the inorganic composite rust inhibitor solution is 1:1, and the concentration of phosphorus in the inorganic composite rust inhibitor is 22%. S2. Carbon nanotubes are dispersed in the inorganic composite rust inhibitor solution to obtain a self-releasing framework solution. The mass ratio of the carbon nanotubes to the inorganic composite rust inhibitor solution is 2:1. The content of carbon nanotubes with a length greater than or equal to 50 nm is 64 wt%. The carbon nanotubes are prepared by chemical vapor deposition on a metal catalyst using methane as the carbon source. The methane flow rate is 100 sccm, the chemical vapor deposition temperature is 700℃, the pressure is 1 atm, and the time is 1 h. The metal catalyst is a cobalt-molybdenum alloy. S3. Ethylenediaminetetramethylenephosphonic acid and the self-releasing framework solution are mixed at a mass ratio of 1:1 and subjected to a hydrothermal reaction to obtain a self-releasing composite corrosion inhibitor; wherein the hydrothermal reaction temperature is 100℃, the time is 12h, and the pressure is 1MPa.
[0026] The concentration of corrosion-inhibiting ions in the solution was measured after soaking in 3.5% NaCl solution for 24 hours. By calculating the ratio of the concentration of corrosion-inhibiting ions in the solution to the concentration of corrosion-inhibiting ions in the self-releasing composite corrosion inhibitor, the corrosion inhibition rate was calculated to be 53%. Corrosion inhibition test: A solution containing 3.5 wt% NaCl was prepared and mixed with the self-releasing composite corrosion inhibitor prepared in Example 1 at a mass ratio of 9:1. HBP300 steel bars were immersed in the solution for 30 days. No obvious corrosion was observed, and the pitting potential was measured to be 486 mV.
[0027] Example 2 Unlike Example 1, in step S1, the mass ratio of sodium dihydrogen phosphate to disodium hydrogen phosphate in the inorganic composite rust inhibitor solution is 1:2; and the concentration of phosphorus in the inorganic composite rust inhibitor is 22%. In step S2, carbon nanotubes are dispersed in the inorganic composite rust inhibitor solution and subjected to ultrasonic oscillation to obtain a self-releasing framework solution; wherein the ultrasonic oscillation power is 200W, the frequency is 40Hz, the time is 2h, and the temperature is 20℃; the chemical vapor deposition temperature is 900℃. In step S3, ethylenediaminetetramethylenephosphonic acid and the self-releasing framework solution are mixed at a mass ratio of 1:2 and subjected to a hydrothermal reaction to obtain a self-releasing composite corrosion inhibitor.
[0028] The concentration of corrosion-inhibiting ions in the solution was measured after soaking in 3.5% NaCl solution for 24 hours. By calculating the ratio of the concentration of corrosion-inhibiting ions in the solution to the concentration of corrosion-inhibiting ions in the self-releasing composite corrosion inhibitor, the corrosion inhibition rate was calculated to be 48%. Corrosion inhibition test: A solution containing 3.5 wt% NaCl was prepared and mixed with the self-releasing composite corrosion inhibitor prepared in Example 2 at a mass ratio of 9:1. HBP300 steel bars were immersed in the solution for 30 days. No obvious corrosion was observed, and the pitting potential was measured to be 420 mV.
[0029] Example 3 Unlike Example 2, in step S1, the mass ratio of sodium dihydrogen phosphate to disodium hydrogen phosphate in the inorganic composite rust inhibitor solution is 2:1. In step S3, ethylenediaminetetramethylenephosphonic acid and the self-releasing framework solution are mixed at a mass ratio of 2:1 and subjected to a hydrothermal reaction to obtain a self-releasing composite corrosion inhibitor.
[0030] The concentration of corrosion-inhibiting ions in the solution was measured after soaking in 3.5% NaCl solution for 24 hours. The corrosion inhibition rate was calculated to be 50.7% by calculating the ratio of the concentration of corrosion-inhibiting ions in the solution to the concentration of corrosion-inhibiting ions in the self-releasing composite corrosion inhibitor.
[0031] Example 4 Unlike Example 2, in step S3, ethylenediaminetetramethylenephosphonic acid and the self-releasing framework solution are mixed at a mass ratio of 2:1 and subjected to a hydrothermal reaction to obtain a self-releasing composite corrosion inhibitor.
[0032] The concentration of corrosion-inhibiting ions in the solution was measured after soaking in 3.5% NaCl solution for 24 hours. The corrosion inhibition rate was calculated to be 56% by calculating the ratio of the concentration of corrosion-inhibiting ions in the solution to the concentration of corrosion-inhibiting ions in the self-releasing composite corrosion inhibitor.
[0033] Example 5 Unlike Example 2, in step S1, the mass ratio of sodium dihydrogen phosphate to disodium hydrogen phosphate in the inorganic composite rust inhibitor solution is 1:3; and the concentration of phosphorus in the inorganic composite rust inhibitor is 22%. In step S2, the temperature for chemical vapor deposition is 700°C; In step S3, ethylenediaminetetramethylenephosphonic acid and the self-releasing framework solution are mixed at a mass ratio of 1:3 and subjected to a hydrothermal reaction to obtain a self-releasing composite corrosion inhibitor.
[0034] The concentration of corrosion-inhibiting ions in the solution was measured after soaking in 3.5% NaCl solution for 24 hours. The corrosion inhibition rate was calculated to be 51% by calculating the ratio of the concentration of corrosion-inhibiting ions in the solution to the concentration of corrosion-inhibiting ions in the self-releasing composite corrosion inhibitor.
[0035] Example 6 Unlike Example 2, in step S1, the mass ratio of sodium dihydrogen phosphate to disodium hydrogen phosphate in the inorganic composite rust inhibitor solution is 3:1. In step S3, ethylenediaminetetramethylenephosphonic acid and the self-releasing framework solution are mixed at a mass ratio of 3:1 and subjected to a hydrothermal reaction to obtain a self-releasing composite corrosion inhibitor.
[0036] The concentration of corrosion-inhibiting ions in the solution was measured after soaking in 3.5% NaCl solution for 24 hours. The corrosion inhibition rate was calculated to be 57% by calculating the ratio of the concentration of corrosion-inhibiting ions in the solution to the concentration of corrosion-inhibiting ions in the self-releasing composite corrosion inhibitor.
[0037] Comparative Example 1 Unlike Example 2, in step S2, the length of the carbon nanotubes is less than 50 nm. The carbon nanotubes are prepared by an arc discharge method with a discharge current of 100 A, an electrode spacing of 2 mm, a discharge time of 90 min, and an electrode rotation speed of 5 r / min. The concentration of corrosion-inhibiting ions in the solution was measured after soaking in 3.5% NaCl solution for 24 hours. The corrosion inhibition rate was calculated to be 21% by calculating the ratio of the concentration of corrosion-inhibiting ions in the solution to the concentration of corrosion-inhibiting ions in the self-releasing composite corrosion inhibitor.
[0038] Corrosion inhibition test: A solution containing 3.5 wt% NaCl was prepared and mixed with the corrosion inhibitor prepared in Comparative Example 1 at a mass ratio of 9:1. HBP300 steel bars were immersed in the solution for 30 days and obvious corrosion occurred. The pitting potential was measured to be 336 mV.
[0039] Comparative Example 2 Unlike Example 2, in step S1, only disodium hydrogen phosphate is used as an inorganic rust inhibitor, wherein the concentration of phosphorus is 25%; The concentration of corrosion-inhibiting ions in the solution was measured after soaking in 3.5% NaCl solution for 24 hours. By calculating the ratio of the concentration of corrosion-inhibiting ions in the solution to the concentration of corrosion-inhibiting ions in the self-releasing composite corrosion inhibitor, the corrosion inhibition rate was calculated to be 34%. Corrosion inhibition test: A solution containing 3.5 wt% NaCl was prepared and mixed with the corrosion inhibitor prepared in Comparative Example 2 at a mass ratio of 9:1. HBP300 steel bars were immersed in the solution for 30 days. No obvious passivation range was found, indicating that its corrosion resistance was poor.
[0040] Comparative Example 3 Unlike Example 2, in step S1, only sodium dihydrogen phosphate is used as an inorganic rust inhibitor, wherein the concentration of phosphorus is 21%; The concentration of corrosion-inhibiting ions in the solution was measured after soaking in 3.5% NaCl solution for 24 hours. The corrosion inhibition rate was calculated to be 32% by calculating the ratio of the concentration of corrosion-inhibiting ions in the solution to the concentration of corrosion-inhibiting ions in the self-releasing composite corrosion inhibitor.
[0041] Comparative Example 4 Unlike Example 2, in step S1, the mass ratio of sodium dihydrogen phosphate and disodium hydrogen phosphate in the inorganic composite rust inhibitor solution is 1:4. The concentration of corrosion-inhibiting ions in the solution was measured after soaking in 3.5% NaCl solution for 24 hours. The corrosion inhibition rate was calculated to be 36% by calculating the ratio of the concentration of corrosion-inhibiting ions in the solution to the concentration of corrosion-inhibiting ions in the self-releasing composite corrosion inhibitor.
[0042] Comparative Example 5 Unlike Example 2, in step S1, the mass ratio of sodium dihydrogen phosphate to disodium hydrogen phosphate in the inorganic composite rust inhibitor solution is 5:1. The concentration of corrosion-inhibiting ions in the solution was measured after soaking in 3.5% NaCl solution for 24 hours. The corrosion inhibition rate was calculated to be 27% by calculating the ratio of the concentration of corrosion-inhibiting ions in the solution to the concentration of corrosion-inhibiting ions in the self-releasing composite corrosion inhibitor.
[0043] Comparative Example 6 Unlike Example 2, no inorganic composite rust inhibitor solution was prepared; instead, the corrosion inhibitor was directly prepared hydrothermally using carbon nanotubes and ethylenediaminetetramethylenephosphonic acid. The concentration of corrosion-inhibiting ions in the solution was measured after soaking in 3.5% NaCl solution for 24 hours. The corrosion inhibition rate was calculated to be 15% by calculating the ratio of the concentration of corrosion-inhibiting ions in the solution to the concentration of corrosion-inhibiting ions in the self-releasing composite corrosion inhibitor.
[0044] Comparative Example 7 Unlike Example 2, step S3 is omitted, resulting in a self-releasing skeleton solution; The concentration of corrosion-inhibiting ions in the solution was measured after soaking in 3.5% NaCl solution for 24 hours. The corrosion inhibition rate was calculated to be 20% by calculating the ratio of the concentration of corrosion-inhibiting ions in the solution to the concentration of corrosion-inhibiting ions in the self-releasing composite corrosion inhibitor.
[0045] Comparative Example 8 Unlike Example 2, in step S2, the mass ratio of the carbon nanotubes to the inorganic composite rust inhibitor solution is 4:1.
[0046] The concentration of corrosion-inhibiting ions in the solution was measured after soaking in 3.5% NaCl solution for 24 hours. The corrosion inhibition rate was calculated to be 13.7% by calculating the ratio of the concentration of corrosion-inhibiting ions in the solution to the concentration of corrosion-inhibiting ions in the self-releasing composite corrosion inhibitor.
[0047] Comparative Example 9 Unlike Example 2, in step S2, the mass ratio of the carbon nanotubes to the inorganic composite rust inhibitor solution is 1:2.
[0048] The concentration of corrosion-inhibiting ions in the solution was measured after soaking in 3.5% NaCl solution for 24 hours. The corrosion inhibition rate was calculated to be 15.4% by calculating the ratio of the concentration of corrosion-inhibiting ions in the solution to the concentration of corrosion-inhibiting ions in the self-releasing composite corrosion inhibitor.
[0049] Comparative Example 10 Unlike Example 2, in step S3, ethylenediaminetetramethylenephosphonic acid and the self-releasing framework solution are mixed at a mass ratio of 1:4 and subjected to a hydrothermal reaction to obtain a self-releasing composite corrosion inhibitor. The concentration of corrosion-inhibiting ions in the solution was measured after soaking in 3.5% NaCl solution for 24 hours. The corrosion inhibition rate was calculated to be 34% by calculating the ratio of the concentration of corrosion-inhibiting ions in the solution to the concentration of corrosion-inhibiting ions in the self-releasing composite corrosion inhibitor.
[0050] Comparative Example 11 Unlike Example 2, in step S3, ethylenediaminetetramethylenephosphonic acid and the self-releasing framework solution are mixed at a mass ratio of 4:1 and subjected to a hydrothermal reaction to obtain a self-releasing composite corrosion inhibitor. The concentration of corrosion-inhibiting ions in the solution was measured after soaking in 3.5% NaCl solution for 24 hours. The corrosion inhibition rate was calculated to be 32% by calculating the ratio of the concentration of corrosion-inhibiting ions in the solution to the concentration of corrosion-inhibiting ions in the self-releasing composite corrosion inhibitor.
[0051] Please see Figure 1 , Figure 1 The images show the morphology of the reinforcing bars after corrosion inhibition tests in Example 1 and Comparative Example 1. It can be seen that the reinforcing bars in Example 1 showed no obvious corrosion, while the reinforcing bars in Comparative Example 1 showed obvious corrosion. Please refer to further details. Figure 2 , Figure 2 The figures show the potentiodynamic polarization curves obtained from corrosion inhibition tests on reinforcing steel bars in some embodiments and comparative examples. Figure 2 It can be concluded that the pitting potential of the steel bars after corrosion inhibition tests in Examples 1 and 2 is significantly higher than that in Comparative Example 1, while Comparative Example 2 has no obvious passivation range, indicating that its corrosion resistance is poor.
[0052] This invention utilizes a combination of inorganic and organic components. The inorganic ions form precipitates on the surface of the reinforcing steel, isolating it from the service environment and preventing corrosion. The organic components have strong adsorption properties and can form a stable protective film on the surface of the reinforcing steel, effectively addressing the high Cl- content of marine environments. - Multiple protections for steel bars in ion service environments; the corrosion inhibitor of this invention, through a carbon nanotube support structure, can achieve rapid diffusion of the corrosion inhibitor, resulting in high corrosion inhibition efficiency and minimal limitations in application.
[0053] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.
Claims
1. A method for preparing a self-releasing composite corrosion inhibitor, characterized in that, Includes the following steps: S1. An inorganic composite rust inhibitor solution is prepared by mixing sodium dihydrogen phosphate and disodium hydrogen phosphate, wherein the mass ratio of sodium dihydrogen phosphate to disodium hydrogen phosphate in the inorganic composite rust inhibitor solution is (1:3) to (3:1), and the concentration of phosphorus in the inorganic composite rust inhibitor solution is 22wt% to 25wt%. S2. Disperse carbon nanotubes in the inorganic composite rust inhibitor solution to obtain a self-releasing framework solution. The mass ratio of the carbon nanotubes to the inorganic composite rust inhibitor solution is 2:
1. The content of carbon nanotubes with a length greater than or equal to 50 nm is greater than or equal to 60 vol%. S3. Ethylenediaminetetramethylenephosphonic acid and the self-releasing skeleton solution are mixed at a mass ratio of (1:3) to (3:1) and subjected to a hydrothermal reaction to obtain a self-releasing composite corrosion inhibitor.
2. The method for preparing a self-releasing composite corrosion inhibitor according to claim 1, characterized in that, In step S2, the carbon nanotubes are prepared by chemical vapor deposition on a metal catalyst using methane as the carbon source.
3. The method for preparing a self-releasing composite corrosion inhibitor according to claim 2, characterized in that, In step S2, the reaction temperature of the chemical vapor deposition is 700~900℃, the reaction pressure is 1 atm, the reaction time is 1~5h, the methane flow rate is 100~300 sccm, and the metal catalyst is a cobalt-molybdenum alloy.
4. The method for preparing a self-releasing composite corrosion inhibitor according to claim 1, characterized in that, Specifically, step S2 involves dispersing carbon nanotubes in the inorganic composite rust inhibitor solution and subjecting them to ultrasonic vibration to obtain a self-releasing skeleton solution. The ultrasonic vibration power is 200-300W, the frequency is 40-50Hz, the time is 1-5h, and the temperature is 20-25℃.
5. The method for preparing a self-releasing composite corrosion inhibitor according to claim 1, characterized in that, In step S3, the hydrothermal reaction is carried out at a temperature of 100°C for 12 hours and at a pressure of 1 MPa.
6. A self-releasing composite corrosion inhibitor, characterized in that, The self-releasing composite corrosion inhibitor is prepared by the preparation method described in any one of claims 1 to 5.
7. The self-releasing composite corrosion inhibitor according to claim 6, characterized in that, The corrosion inhibitor has a release rate of greater than or equal to 45% after being soaked in a 3.5 wt% NaCl solution for 24 hours.
8. The self-releasing composite corrosion inhibitor according to claim 6, characterized in that, A solution containing 3.5 wt% NaCl was prepared and mixed with the self-releasing composite corrosion inhibitor at a mass ratio of 9:
1. After immersing HBP300 steel bars in the solution for 30 days, no obvious rust was observed, and the pitting potential was greater than or equal to 400 mV.