Corrosion and wear resistant polyurethane-silicone oil composite coating on carbon steel surface and preparation method thereof

Abstract

The application discloses a kind of carbon steel surface corrosion-resistant wear-resistant polyurethane-silicone oil composite coating and preparation method, aniline oligomer is used to functionalize graphene oxide and obtain aniline oligomer functionalized graphene oxide, then silicone oil is added to polyurethane to obtain polyurethane-silicone oil composite slurry, then aniline oligomer functionalized graphene oxide is added to polyurethane-silicone oil composite slurry, fully mixed and then sprayed on the surface of substrate, and dried and cured to obtain corrosion-resistant wear-resistant polyurethane-silicone oil composite coating.The application can improve the dispersibility and compatibility of graphene oxide in the polyurethane matrix, improve the permeability of the graphene oxide layer, thereby enhancing the friction and corrosion resistance of the carbon steel surface corrosion-resistant wear-resistant polyurethane-silicone oil composite coating.

Description

Technical Field

[0001] This invention belongs to the field of metal surface treatment and corrosion and protection, and relates to a corrosion-resistant and wear-resistant polyurethane-silicone oil composite coating for carbon steel surface and its preparation method. Background Technology

[0002] Carbon steel is widely used in industries such as machinery, construction, and transportation. Due to its low alloy content, this material has relatively low corrosion resistance. Applying a corrosion-resistant coating to its surface can effectively improve corrosion resistance and significantly extend its corrosion life. Polyurethane (PU) is widely used in the field of metal corrosion and wear protection due to its excellent anti-corrosion and wear-resistant properties. However, with increasingly harsh application areas and service environments, it is necessary to modify polyurethane coatings to further improve their anti-corrosion and wear-resistant properties.

[0003] Graphene oxide (GO), a derivative of graphene, is a typical two-dimensional material with excellent mechanical properties, low weight, and superior barrier, shielding, and chemical stability, making it suitable for polymer-based reinforced coatings to improve corrosion resistance. However, the inherent van der Waals forces and π-π interactions of GO can lead to stacking and agglomeration, causing material degradation and hindering the achievement of expected performance. Furthermore, the performance of GO largely depends on the quality of the matrix-metal interface, which determines the load transfer mechanism and the blocking of corrosive agents. Existing technologies utilize GO to modify polyurethane coatings, but the improvement in corrosion resistance is limited. Moreover, due to the encapsulation of other film-forming substances or fillers, the extremely low surface tension of GO makes it difficult to integrate with other materials, causing it to lose its unique advantages and its significance in the field of anti-corrosion coatings. In some cases, the corrosion resistance of coatings with added GO is even inferior to that of the original coating. In addition, Liu Xiao et al. prepared graphene oxide / polyimide composites, and their research found that graphene oxide effectively improved the mechanical and tribological properties of the material, with the optimal polyimide ratio being 3 wt.%. Ramezanzadeh et al. prepared functionalized graphene using aromatic diamines and p-phenylenediamine, which exhibited good dispersibility and tight bonding with the matrix, significantly improving the coating's density, barrier properties, and further enhancing its corrosion resistance. Therefore, it is foreseeable that the combined use of silicone oil and graphene oxide can simultaneously meet the requirements of lubrication and corrosion protection.

[0004] In view of the above, there is an urgent need to develop a polyurethane composite coating with high corrosion and wear resistance. Polyurethane composite coatings can be prepared using graphene oxide, which can improve the wear and corrosion resistance of the coating and increase the service life of carbon steel. Summary of the Invention

[0005] To address the aforementioned deficiencies in existing technologies, the present invention aims to provide a corrosion-resistant and wear-resistant polyurethane-silicone oil composite coating for carbon steel surfaces and its preparation method. Silicone oil (TSOs) is introduced as a liquid lubricant into polyurethane (PU), and graphene oxide functionalized with aniline oligomers is added. This improves the dispersibility and compatibility of graphene oxide in the polyurethane matrix, enhances the impermeability of the graphene oxide layer, and thereby strengthens the friction and corrosion resistance of the corrosion-resistant and wear-resistant polyurethane-silicone oil composite coating on carbon steel surfaces.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] The first aspect of this invention provides a method for preparing a corrosion-resistant and wear-resistant polyurethane-silicone oil composite coating on a carbon steel surface, comprising the following steps:

[0008] S1: Graphene oxide is functionalized using aniline oligomers to obtain aniline oligomer-functionalized graphene oxide;

[0009] S2: Add silicone oil to polyurethane to obtain polyurethane-silicone oil composite slurry;

[0010] S3: The aniline oligomer functionalized graphene oxide is added to the polyurethane-silicone oil composite slurry, mixed thoroughly, sprayed onto the substrate surface, and dried and cured to obtain a corrosion-resistant and wear-resistant polyurethane-silicone oil composite coating.

[0011] Preferably, the preparation process of aniline oligomer-functionalized graphene oxide in step S1 is as follows:

[0012] S11, aniline is added to sodium dodecyl sulfonate solution, mechanically mixed evenly, ammonium persulfate solution is added dropwise, stirred evenly, and then filtered, washed and dried to obtain aniline oligomers;

[0013] S12, dispersing graphene oxide in deionized water to obtain a graphene oxide suspension;

[0014] S13, add hydrochloric acid and aniline oligomer to deionized water, and drip sodium nitrite, and treat with ice bath to obtain a mixed solution. Then, ultrasonically disperse the graphene oxide suspension and mix it with the mixed solution. After filtration, washing and drying, aniline oligomer-functionalized graphene oxide is obtained.

[0015] Preferably, in step S11:

[0016] The sodium dodecyl sulfonate solution has a molar concentration of 0.006–0.008 mol / L and a usage volume of 1–3 ml; the aniline used is 0.25–0.35 g; and / or

[0017] The mechanical mixing time is 10–30 min; and / or

[0018] The amount of ammonium persulfate solution used is 1–3 ml, and the molar concentration is 0.2–0.8 mol / L; and / or

[0019] The stirring time is 15–30 min; and / or

[0020] The washing process uses deionized water and acetone.

[0021] Preferably, in step S12, the mass concentration of the graphene oxide suspension is 0.05–0.10 wt%.

[0022] Preferably, in step S13:

[0023] The amount of deionized water used is 50-100 ml; the amount of hydrochloric acid used is 0.5-1 ml, and the molar concentration of the hydrochloric acid is 1-2 mol / L; the amount of aniline oligomer used is 50-80 mg; and / or

[0024] The amount of sodium nitrite used is 3-5 ml, and the molar concentration is 0.14-0.25 mol / L; and / or

[0025] The ice bath treatment time is 25–60 min; and / or

[0026] The ultrasonic dispersion time of the graphene oxide suspension is 20–30 min; and / or

[0027] When the graphene oxide suspension is ultrasonically dispersed and then mixed with the mixed solution, the mixing temperature is 60–90°C and the stirring time is 3–4 hours; and / or

[0028] The washing process involves washing with deionized water and acetone 6 to 10 times.

[0029] Preferably, the polyurethane preparation process in step S2 is as follows: after the polyhydroxy compound is mixed evenly with toluene and dehydrated isophorone diisocyanate, it is stirred at 50-70°C in a nitrogen atmosphere for 4-8 hours.

[0030] Preferably, the mass ratio of the polyhydroxy compound to toluene and dehydrated isophorone diisocyanate is 100:(120-300):(60-88).

[0031] Preferably, in the preparation process of the polyurethane-silicone oil composite slurry in step S2:

[0032] The silicone oil is one of methyl-terminated silicone oil, hydroxyl-terminated silicone oil, and vinyl-terminated silicone oil; and / or

[0033] The amount of silicone oil used is 5 to 50 wt% of the mass of the polyurethane.

[0034] Preferably, in the preparation process of the corrosion-resistant and wear-resistant polyurethane-silicone oil composite coating in step S3:

[0035] The amount of aniline oligomer-functionalized graphene oxide used is 2.5 to 7.5 wt% of the mass of the polyurethane-silicone oil composite slurry; and / or

[0036] When the aniline oligomer-functionalized graphene oxide is mixed with the polyurethane-silicone oil composite slurry, the mixing temperature is 60–80°C, the atmosphere is nitrogen, and the stirring time is 1–4 hours; and / or

[0037] During the drying and curing process, the drying temperature is 120-150℃ and the curing time is 1-3 hours.

[0038] The second aspect of the present invention provides a corrosion-resistant and wear-resistant polyurethane-silicone oil composite coating for carbon steel surface obtained by the preparation method of the corrosion-resistant and wear-resistant polyurethane-silicone oil composite coating for carbon steel surface as described in the first aspect of the present invention.

[0039] The corrosion-resistant and wear-resistant polyurethane-silicone oil composite coating for carbon steel surfaces and its preparation method provided by this invention have the following beneficial effects:

[0040] 1. Silicone oil (TSOs) is introduced into polyurethane (PU) as a liquid lubricant and supplemented with graphene oxide functionalized with aniline oligomers, thereby improving the dispersibility and compatibility of graphene oxide in the polyurethane matrix, enhancing the impermeability of the graphene oxide layer, and thus enhancing the friction resistance and corrosion resistance of the corrosion-resistant and wear-resistant polyurethane-silicone oil composite coating on the carbon steel surface.

[0041] 2. Silicone oil at different ends is introduced as a liquid lubricant into the polyurethane spatial matrix, and aniline oligomers (with their unique proton doping reaction) are used to improve the dispersion and compatibility of graphene oxide in the polyurethane matrix, thereby improving the anti-permeability of the graphene oxide layer. This results in a corrosion-resistant and wear-resistant polyurethane-silicone oil composite coating on carbon steel surfaces with ultra-low friction and corrosion resistance.

[0042] 3. In this invention, the aniline oligomers in the graphene oxide functionalized with aniline oligomers crosslink with the polyurethane resin coating skeleton, which can make the corrosion-resistant and wear-resistant polyurethane-silicone oil composite coating on the carbon steel surface more dense and stronger. Therefore, the corrosion-resistant and wear-resistant polyurethane-silicone oil composite coating on the carbon steel surface has the best anti-corrosion performance. Attached Figure Description

[0043] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0044] Figure 1A comparison chart of the friction coefficients of the corrosion-resistant and wear-resistant polyurethane-silicone oil composite coatings on carbon steel surfaces prepared according to the present invention.

[0045] Figure 2 This is a comparison chart of the wear life of the corrosion-resistant and wear-resistant polyurethane-silicone oil composite coating on carbon steel surface prepared according to the present invention. Detailed Implementation

[0046] To better understand the above-mentioned technical solutions of the present invention, the technical solutions of the present invention will be further described below in conjunction with embodiments.

[0047] The present invention provides a corrosion-resistant and wear-resistant polyurethane-silicone oil composite coating for carbon steel surfaces and its preparation method. The method involves functionalizing graphene oxide with aniline oligomers to obtain aniline oligomer-functionalized graphene oxide, then adding silicone oil to polyurethane to obtain a polyurethane-silicone oil composite slurry. Subsequently, the aniline oligomer-functionalized graphene oxide is added to the polyurethane-silicone oil composite slurry, thoroughly mixed, and then sprayed onto the substrate surface, followed by drying and curing to obtain the corrosion-resistant and wear-resistant polyurethane-silicone oil composite coating. The specific steps are as follows:

[0048] (1) Aniline oligomer functionalized graphene oxide (hereinafter referred to as AFOG)

[0049] Specifically, the process involves first preparing aniline oligomers, then preparing a graphene oxide suspension, and finally functionalizing the graphene oxide suspension with the aniline oligomers to obtain AFOG; the specific steps include:

[0050] S11, aniline is added to sodium dodecyl sulfate solution (hereinafter referred to as SDS), mechanically mixed for 10-30 min until homogeneous, then ammonium persulfate solution (hereinafter referred to as APS) is added dropwise, stirred until homogeneous, filtered, washed, and dried to obtain aniline oligomer (a blackish-yellow powder); in specific embodiments, the molar concentration of sodium dodecyl sulfate solution is 0.006-0.008 mol / L, the amount used is 1-3 ml, the amount of aniline used is 0.25-0.35 g; the mechanical mixing time is 10-30 min; the amount of ammonium persulfate solution used is 1-3 ml, the molar concentration is 0.2-0.8 mol / L; the stirring time is 15-30 min; the washing process uses deionized water and acetone.

[0051] S12, dispersing graphene oxide in deionized water to obtain a graphene oxide suspension; wherein the mass concentration of the graphene oxide suspension is 0.05-0.1 wt%.

[0052] S13: Add hydrochloric acid and the aniline oligomer prepared in step S11 to deionized water, and add sodium nitrite dropwise. Treat in an ice bath for 25–60 min to obtain a mixed solution. In a specific embodiment, the amount of deionized water used is: 0.5–1 ml of hydrochloric acid with a molar concentration of 1–2 mol / L; the amount of aniline oligomer used is 50–80 mg; and the amount of sodium nitrite used is 3–5 ml with a molar concentration of 0.14–0.25 mol / L. Subsequently, the graphene oxide suspension is ultrasonically dispersed for 20–30 min and then mixed with the mixed solution at a mixing temperature of 60–90 °C for 3–4 h. After filtration, washing, and drying, AOFG is obtained. The washing process involves washing with deionized water and acetone 6–10 times.

[0053] (2) Polyurethane-silicone oil composite slurry (hereinafter referred to as X-TSO / PU)

[0054] Specifically, the polyurethane is first prepared by mixing a polyhydroxy compound (such as glycerol) with toluene and dehydrated isophorone diisocyanate, and then stirring at 50-70°C under a nitrogen atmosphere for 4-8 hours. The mass ratio of the polyhydroxy compound to toluene and dehydrated isophorone diisocyanate is 100:(120-300):(60-88). For example, 100g of the polyhydroxy compound is mixed with 120-300g of toluene and 60-88g of dehydrated isophorone diisocyanate to prepare the polyurethane. The silicone oil is then added to the polyurethane to obtain a polyurethane-silicone oil composite slurry, denoted as X-TSO / PU. Different silicone oils with different functional groups produce different polyurethane-silicone oil composite slurries. The silicone oil can be one of methyl-terminated silicone oil (hereinafter referred to as CH3-TSO), hydroxyl-terminated silicone oil (hereinafter referred to as OH-TSO), or vinyl-terminated silicone oil (hereinafter referred to as C2H4-TSO). The amount of silicone oil used is 5 to 50 wt% of the mass of the polyurethane. In a further preferred embodiment, the amount of silicone oil used is 40 to 50 wt% of the mass of the polyurethane.

[0055] (3) Corrosion-resistant and wear-resistant polyurethane-silicone oil composite coating

[0056] Specifically, aniline oligomer-functionalized graphene oxide (AFOG) is added to polyurethane-silicone oil composite slurry X-TSO / PU. After thorough mixing at 60-80℃ under a nitrogen atmosphere for 1-4 hours, the mixture is sprayed onto the surface of a substrate (such as plain carbon steel) and dried and cured at 120-150℃ for 1-3 hours to obtain a corrosion-resistant and wear-resistant polyurethane-silicone oil composite coating, denoted as AOFG / X-TSO / PU ternary composite coating. The amount of aniline oligomer-functionalized graphene oxide used is 2.5-7.5 wt% of the mass of the polyurethane-silicone oil composite slurry.

[0057] The performance of the corrosion-resistant and wear-resistant polyurethane-silicone oil composite coating prepared above was evaluated: the tribological properties of the coating were evaluated using a CSM tribological testing machine: the coefficient of friction and wear life were measured and automatically recorded under maximum linear velocity and a load of 15 N; for specific results, please refer to [link to relevant documentation]. Figure 1 , Figure 2 Under the same conditions, the friction coefficient and wear life of corrosion-resistant and wear-resistant polyurethane-silicone oil composite coatings obtained by using silicone oils with different functional groups and with different mass ratios of silicone oils with different functional groups to polyurethane are different; combined with Figure 1 As shown, when the mass ratio of silicone oil to polyurethane is the same, the corrosion-resistant and wear-resistant polyurethane-silicone oil composite coating prepared with hydroxyl-terminated silicone oil has the highest coefficient of friction; combined with Figure 2 As shown, when the mass ratio of silicone oil to polyurethane is ≤12.5wt%, the corrosion-resistant and wear-resistant polyurethane-silicone oil composite coating prepared with methyl-terminated silicone oil has the longest wear life. When the mass ratio of silicone oil to polyurethane is ≥17.5%, the corrosion-resistant and wear-resistant polyurethane-silicone oil composite coating prepared with hydroxyl-terminated silicone oil has the longest wear life. Electrochemical testing was used to evaluate the corrosion performance of the coating: specifically, potentiodynamic polarization curves were used for testing. Polarization curves of coating samples of equal area were measured under the same conditions. The reference electrode was a saturated calomel electrode (SCE), the scanning range was -0.35 to -0.25 V, and the scanning rate was 1 mV / s. The results showed that the corrosion current density on the surface of the corrosion-resistant and wear-resistant polyurethane-silicone oil composite coating remained at a low level, specifically not exceeding 2.5 μA / cm². 2 Therefore, it can be seen that the surface of the corrosion-resistant and wear-resistant polyurethane-silicone oil composite coating hardly corrodes.

[0058] The preparation method of the corrosion-resistant and wear-resistant polyurethane-silicone oil composite coating on carbon steel surface of the present invention will be further described below with specific examples.

[0059] Example 1

[0060] In this embodiment, Q345B carbon steel was selected as the metal substrate coating sample;

[0061] Preparation of aniline oligomers: 0.25 g aniline was added to 2 mL of SDS (0.0069 mol / L) solution and mechanically mixed for 10 minutes until homogeneous. Then, 1 mL of APS solution (0.2 mol / L) was added dropwise, stirred for 15 minutes, filtered, washed with deionized water and acetone, and dried to obtain a blackish-yellow powder of aniline oligomers. Then, 0.5 mL of HCl (1 mol / L) and 50 mg of aniline oligomers were added to 50 mL of deionized water, followed by the addition of 3 mL of sodium nitrite (0.14 mol / L). The mixture was in an ice bath for 30 minutes to obtain a mixed solution. Subsequently, 80 mL of graphene oxide suspension (0.05 wt.%) was ultrasonically dispersed for 20 minutes and mixed with the above mixed solution. The mixture was stirred at 60 °C for 3 hours. After filtration, washing with deionized water and acetone six times, and drying, AOFG was finally obtained.

[0062] Polyurethane was obtained by mixing 100g of a polyhydroxy compound with 120-300g of toluene and 60-88g of dehydrated isophorone diisocyanate at 50-70°C under a nitrogen atmosphere for 4-8 hours; then 40-50g of CH3-TSO was added to 100g of polyurethane to obtain CH3-TSO / PU.

[0063] 0.025 g of aniline oligomer-functionalized graphene oxide (AOFG) was added to the above CH3-TSO / PU mixture and stirred with a slow nitrogen flow at 60 °C for 1 hour, then sprayed onto a substrate. The mixture was then cured at 120 °C for 1 hour to obtain an AOFG / CH3-TSO / PU ternary composite coating.

[0064] The tribological properties of the coating were evaluated using a CSM tribological testing machine: the coefficient of friction and wear life were measured and automatically recorded under a maximum linear velocity of 3 cm / s and a load of 15 N. Electrochemical testing was performed using potentiodynamic polarization curves. Polarization curves of coating samples of equal area were measured under the same conditions. The reference electrode was a saturated calomel electrode (SCE), the scan range was -0.35 to -0.25 V, and the scan rate was 1 mV / s. Specific results are shown in Table 1.

[0065] Example 2

[0066] In this embodiment, Q345B carbon steel was selected as the metal substrate coating sample;

[0067] Preparation of aniline oligomers: 0.26 g aniline was added to 2.5 mL of SDS (0.0069 mol / L) solution and mechanically mixed for 15 minutes until homogeneous. Then, 1.5 mL of APS solution (0.2 mol / L) was added dropwise, stirred for 18 minutes, filtered, washed with deionized water and acetone, and dried to obtain a blackish-yellow powder of aniline oligomers. Then, 0.6 mL of HCl (1 mol / L) and 50–80 mg of aniline oligomers were added to 60 mL of deionized water, followed by dropwise addition of 3.5 mL of sodium nitrite (0.14 mol / L), and the mixture was in an ice bath for 38 minutes to obtain a mixed solution. Subsequently, 85 mL of graphene oxide suspension (0.05 wt.%) was ultrasonically dispersed for 20–30 minutes and mixed with the above mixed solution, and stirred at 60 °C for 3.2 h. After filtration, washing with deionized water and acetone seven times, and drying, AOFG was finally obtained.

[0068] Polyurethane was obtained by mixing 100g of a polyhydroxy compound with 120-300g of toluene and 60-88g of dehydrated isophorone diisocyanate at 50-70°C under a nitrogen atmosphere for 4-8 hours; then 40-50g of CH3-TSO was added to 100g of polyurethane to obtain CH3-TSO / PU.

[0069] 0.05 g of the prepared AOFG was added to the above CH3-TSO / PU and stirred with a slow nitrogen flow at 65 °C for 1.5 hours, then sprayed onto the substrate. It was then cured at 125 °C for 1 hour to obtain the AOFG / CH3-TSO / PU ternary composite coating.

[0070] The tribological properties of the coating were evaluated using a CSM tribological testing machine: the coefficient of friction and wear life were measured and automatically recorded under a maximum linear velocity of 7 cm / s and a load of 15 N. Electrochemical testing was performed using potentiodynamic polarization curves. Polarization curves of coating samples of equal area were measured under the same conditions. The reference electrode was a saturated calomel electrode (SCE), the scan range was -0.35 to -0.25 V, and the scan rate was 1 mV / s. Specific results are shown in Table 1.

[0071] Example 3

[0072] In this embodiment, 45 carbon steel was selected as the metal substrate coating sample;

[0073] Preparation of aniline oligomers: 0.30 g aniline was added to 2 mL of SDS (0.0069 mol / L) solution and mechanically mixed for 20 minutes until homogeneous. Then, 2 mL of APS solution (0.2 mol / L) was added dropwise, and the mixture was stirred for 20 minutes. After filtration, the mixture was washed with deionized water and acetone and dried to obtain a blackish-yellow powder of aniline oligomers. Then, 0.7 mL of HCl (1 mol / L) and 50–80 mg of aniline oligomers were added to 70 mL of deionized water, followed by the addition of 4 mL of sodium nitrite (0.14 mol / L). The mixture was in an ice bath for 45 minutes to obtain a mixed solution. Subsequently, 60 mL of graphene oxide suspension (0.05 wt.%) was ultrasonically dispersed for 25 minutes and mixed with the above mixed solution. The mixture was stirred at 60 °C for 3.4 h. After filtration, washing with deionized water and acetone eight times, and drying, AOFG was finally obtained.

[0074] Polyurethane was obtained by mixing 100g of a polyhydroxy compound with 120-300g of toluene and 60-88g of dehydrated isophorone diisocyanate at 50-70°C under a nitrogen atmosphere for 4-8 hours; then 40-50g of CH3-TSO was added to 100g of polyurethane to obtain CH3-TSO / PU.

[0075] 0.055 g of the prepared AOFG was added to the above CH3-TSO / PU and stirred with a slow nitrogen flow at 65 °C for 2 hours, then sprayed onto the substrate. It was then cured at 130 °C for 3 hours to obtain the AOFG / CH3-TSO / PU ternary composite coating.

[0076] The tribological properties of the coating were evaluated using a CSM tribological testing machine: the coefficient of friction and wear life were measured and automatically recorded under a maximum linear velocity of 7 cm / s and a load of 15 N. Electrochemical testing was performed using potentiodynamic polarization curves. Polarization curves of coating samples of equal area were measured under the same conditions. The reference electrode was a saturated calomel electrode (SCE), the scan range was -0.35 to -0.25 V, and the scan rate was 1 mV / s. Specific results are shown in Table 1.

[0077] Example 4

[0078] In this embodiment, T9 carbon steel was selected as the metal substrate coating sample;

[0079] Preparation of aniline oligomers: 0.28 g aniline was added to 2 mL of SDS (0.0069 mol / L) solution and mechanically mixed for 22 minutes until homogeneous. Then, 1–3 mL of APS solution (0.2 mol / L) was added dropwise, and the mixture was stirred for 26 minutes. After filtration, the mixture was washed with deionized water and acetone and dried to obtain a blackish-yellow powder of aniline oligomers. Then, 0.8 mL of HCl (1 mol / L) and 75 mg of aniline oligomers were added to 80 mL of deionized water, followed by the dropwise addition of 4.5 mL of sodium nitrite (0.14 mol / L). The mixture was in an ice bath for 50 minutes to obtain a mixed solution. Subsequently, 95 mL of graphene oxide suspension (0.05 wt.%) was ultrasonically dispersed for 28 minutes and mixed with the above mixed solution. The mixture was stirred at 60 °C for 3.6 h. After filtration, washing with deionized water and acetone nine times, and drying, AOFG was finally obtained.

[0080] Polyurethane was obtained by mixing 100g of a polyhydroxy compound with 120-300g of toluene and 60-88g of dehydrated isophorone diisocyanate at 50-70°C under a nitrogen atmosphere for 4-8 hours; then 40-50g of CH3-TSO was added to 100g of polyurethane to obtain CH3-TSO / PU.

[0081] 0.07 g of aniline oligomer-functionalized graphene oxide (AOFG) was added to the above CH3-TSO / PU and stirred with a slow nitrogen flow at 80 °C for 3 hours, then sprayed onto the substrate. It was then cured at 140 °C for 3 hours to obtain an AOFG / CH3-TSO / PU ternary composite coating.

[0082] The tribological properties of the coating were evaluated using a CSM tribological testing machine: the coefficient of friction and wear life were measured and automatically recorded under a maximum linear velocity of 7 cm / s and a load of 15 N. Electrochemical testing was performed using potentiodynamic polarization curves. Polarization curves of coating samples of equal area were measured under the same conditions. The reference electrode was a saturated calomel electrode (SCE), the scan range was -0.35 to -0.25 V, and the scan rate was 1 mV / s. Specific results are shown in Table 1.

[0083] Example 5

[0084] In this embodiment, T9 carbon steel was selected as the metal substrate coating sample;

[0085] Preparation of aniline oligomers: 0.33 g aniline was added to 2 mL of SDS (0.0069 mol / L) solution and mechanically mixed for 19 minutes until homogeneous. Then, 1–3 mL of APS solution (0.2 mol / L) was added dropwise, stirred for 27 minutes, filtered, washed with deionized water and acetone, and dried to obtain a blackish-yellow powder of aniline oligomers. Then, 0.9 mL of HCl (1 mol / L) and 50–80 mg of aniline oligomers were added to 50–100 mL of deionized water, followed by dropwise addition of 4.7 mL of sodium nitrite (0.14 mol / L), and the mixture was in an ice bath for 55 minutes to obtain a mixed solution. Subsequently, 98 mL of graphene oxide suspension (0.05 wt.%) was ultrasonically dispersed for 29 minutes and mixed with the above mixed solution, and stirred at 60 °C for 3.8 h. After filtration, washing 10 times with deionized water and acetone, and drying, AOFG was finally obtained.

[0086] Polyurethane was obtained by mixing 100g of a polyhydroxy compound with 120-300g of toluene and 60-88g of dehydrated isophorone diisocyanate at 50-70°C under a nitrogen atmosphere for 4-8 hours; then 40-50g of CH3-TSO was added to 100g of polyurethane to obtain CH3-TSO / PU.

[0087] 0.075 g of the prepared AOFG was added to the above CH3-TSO / PU and stirred with a slow nitrogen flow at 80 °C for 3.8 hours, then sprayed onto the substrate. It was then cured at 130 °C for 3 hours to obtain the AOFG / CH3-TSO / PU ternary composite coating.

[0088] The tribological properties of the coating were evaluated using a CSM tribological testing machine: the coefficient of friction and wear life were measured and automatically recorded under a maximum linear velocity of 6 cm / s and a load of 15 N. Electrochemical testing was performed using potentiodynamic polarization curves. Polarization curves of coating samples of equal area were measured under the same conditions. The reference electrode was a saturated calomel electrode (SCE), the scan range was -0.35 to -0.25 V, and the scan rate was 1 mV / s. Specific results are shown in Table 1.

[0089] Example 6

[0090] In this embodiment, Q345B carbon steel was selected as the metal substrate coating sample;

[0091] Preparation of aniline oligomers: 0.35 g aniline was added to 2 mL of SDS (0.0069 mol / L) solution and mechanically mixed for 19 minutes until homogeneous. Then, 1–3 mL of APS solution (0.2 mol / L) was added dropwise, stirred for 30 minutes, filtered, washed with deionized water and acetone, and dried to obtain a blackish-yellow powder of aniline oligomers. Then, 1 mL of HCl (1 mol / L) and 50–80 mg of aniline oligomers were added to 100 mL of deionized water, followed by the dropwise addition of 5 mL of sodium nitrite (0.14 mol / L). The mixture was in an ice bath for 60 minutes to obtain a mixed solution. Subsequently, 100 mL of graphene oxide suspension (0.05 wt.%) was ultrasonically dispersed for 30 minutes and mixed with the above mixed solution. The mixture was stirred at 60 °C for 4 hours. After filtration, washing 10 times with deionized water and acetone, and drying, AOFG was finally obtained.

[0092] Polyurethane was obtained by mixing 100g of a polyhydroxy compound with 120-300g of toluene and 60-88g of dehydrated isophorone diisocyanate at 50-70°C under a nitrogen atmosphere for 4-8 hours; then 40-50g of CH3-TSO was added to 100g of polyurethane to obtain CH3-TSO / PU.

[0093] 0.075 g of the prepared AOFG was added to the above CH3-TSO / PU and stirred with a slow nitrogen flow at 80 °C for 3 hours, then sprayed onto the substrate. It was then cured at 125 °C for 3 hours to obtain the AOFG / CH3-TSO / PU ternary composite coating.

[0094] The tribological properties of the coating were evaluated using a CSM tribological testing machine: the coefficient of friction and wear life were measured and automatically recorded under a maximum linear velocity of 6 cm / s and a load of 15 N. Electrochemical testing was performed using potentiodynamic polarization curves. Polarization curves of coating samples of equal area were measured under the same conditions. The reference electrode was a saturated calomel electrode (SCE), the scan range was -0.35 to -0.25 V, and the scan rate was 1 mV / s. Specific results are shown in Table 1.

[0095] Table 1 shows the performance of the AAFG / X-TSO / PU ternary composite coating in the examples.

[0096]

[0097]

[0098] As shown in Table 1, the corrosion-resistant and wear-resistant polyurethane-silicone oil composite coatings prepared in Examples 1-6 have a dense structure. No pores or cracks were observed under 800x magnification, and the wear loss during the wear test did not exceed 45 mg. This was compared with the corrosion potential (-0.55 to -0.7 V) and corrosion current (10 to 50 μA / cm) of ordinary carbon steel surfaces. 2 In electrochemical tests, the corrosion current density on the surface of the corrosion-resistant and wear-resistant polyurethane-silicone oil composite coating in this embodiment does not exceed 2.5 μA / cm². 2 The corrosion current density on the coating surface generally remains low, indicating that the coating provides good protection for the substrate. In terms of specific values, it can be considered that almost no corrosion occurs on the metal surface. In addition, the corrosion potential of the coating surface in this embodiment is between -0.31 and -0.86V, which is comparable to the corrosion potential of the plain carbon steel surface, and is closer to the upper limit and closer to 0. Considering both the corrosion current density and corrosion potential of the coating surface, it can be seen that the coating surface has a low tendency to corrode, which is also due to the good protective properties of the coating.

[0099] Those skilled in the art should recognize that the above embodiments are merely illustrative of the present invention and are not intended to limit the present invention. Any variations or modifications to the above embodiments that are within the spirit and essence of the present invention will fall within the scope of the claims of the present invention.

Claims

1. A method for preparing a corrosion and wear resistant polyurethane-silicone composite coating on a carbon steel surface, characterized by, The method comprises the following steps: S1: functionalizing graphene oxide with aniline oligomers to obtain aniline oligomer functionalized graphene oxide, The preparation process of the aniline oligomer functionalized graphene oxide in step S1 is as follows: S11: aniline is added to a sodium dodecyl sulfonate solution, mechanically mixed uniformly, then ammonium persulfate solution is added dropwise, stirred uniformly, and then filtered, washed, and dried to obtain aniline oligomers; S12: disperse graphene oxide in deionized water to obtain a graphene oxide suspension; S13: add hydrochloric acid and aniline oligomers to deionized water, and drop sodium nitrite to obtain a mixed solution, then ultrasonically disperse the graphene oxide suspension and mix it with the mixed solution, and then filter, wash, and dry to obtain aniline oligomer functionalized graphene oxide; S2: add silicone oil to polyurethane to obtain a polyurethane-silicone oil composite slurry, The preparation process of the polyurethane in step S2 is as follows: mix polyhydroxy compound with toluene and dehydrated isophorone diisocyanate uniformly, then stir at 50-70°C under a nitrogen atmosphere for 4-8h; The preparation process of the polyurethane-silicone oil composite slurry in step S2 is as follows: The silicone oil is one of methyl-terminated silicone oil, hydroxyl-terminated silicone oil, and vinyl-terminated silicone oil; The amount of silicone oil used is 5-50wt% of the mass of the polyurethane; S3: add the aniline oligomer functionalized graphene oxide to the polyurethane-silicone oil composite slurry, mix thoroughly, then spray on the surface of a substrate, and dry and cure to obtain a corrosion-resistant and wear-resistant polyurethane-silicone oil composite coating, The preparation process of the corrosion-resistant and wear-resistant polyurethane-silicone oil composite coating in step S3 is as follows: The amount of aniline oligomer functionalized graphene oxide used is 2.5-7.5wt% of the mass of the polyurethane-silicone oil composite slurry; When mixing the aniline oligomer functionalized graphene oxide with the polyurethane-silicone oil composite slurry, the mixing temperature is 60-80°C, the atmosphere is a nitrogen atmosphere, and the stirring time is 1-4h; In the drying and curing process, the drying temperature is 120-150°C, and the curing time is 1-3h, The corrosion current density of the corrosion-resistant and wear-resistant polyurethane-silicone oil composite coating surface is not more than 2.5 μA / cm 2 .

2. A process for the preparation of corrosion and wear resistant polyurethane-silicone oil composite coating on carbon steel surface as claimed in claim 1, wherein In step S11: The molar concentration of the sodium dodecyl sulfonate solution is 0.006-0.008mol / L, the amount used is 1-3ml, and the amount of aniline used is 0.25-0.35g; and / or The mechanical mixing time is 10-30min; and / or The amount of ammonium persulfate solution used is 1-3ml, and the molar concentration is 0.2-0.8mol / L; and / or The stirring time is 15-30min; and / or The washing process uses deionized water and acetone.

3. The process for the preparation of corrosion and wear resistant polyurethane-silicone oil composite coating on carbon steel surface as claimed in claim 1, wherein In step S12, the mass concentration of the graphene oxide suspension is 0.05-0.10wt%.

4. The process for the preparation of corrosion and wear resistant polyurethane-silicone composite coating on carbon steel surface as claimed in claim 1, wherein In step S13: The amount of deionized water used is 50-100ml; the amount of hydrochloric acid used is 0.5-1ml, and the molar concentration of the hydrochloric acid is 1-2mol / L; the amount of aniline oligomers used is 50-80mg; and / or The sodium nitrite is used in an amount of 3-5 ml and has a molar concentration of 0.14-0.25 mol / L; and / or The ice bath treatment time is 25-60 min; and / or The ultrasonic dispersion time of the graphene oxide suspension is 20-30 min; and / or When the ultrasonic dispersed graphene oxide suspension is mixed with the mixed solution, the mixing temperature is 60-90 DEG C, and the stirring time is 3-4 h; and / or The deionized water and acetone are used for washing 6-10 times in the washing process.

5. The process for the preparation of corrosion and wear resistant polyurethane-silicone composite coating on carbon steel surface as claimed in claim 1, wherein The mass ratio of the polyhydroxy compound, toluene and dehydrated isophorone diisocyanate is 100:(120-300):(60-88).

6. The process for preparation of corrosion and wear resistant polyurethane-silicone composite coating on carbon steel surface as claimed in claim 1 wherein, In the step S2, the amount of the silicone oil used is 40-50 wt% of the mass of the polyurethane.

7. A carbon steel surface corrosion and wear resistant polyurethane-silicone composite coating obtained by the method according to any one of claims 1 to 6, wherein the corrosion and wear resistant polyurethane-silicone composite coating has a corrosion current density of not more than 2.5 μA / cm2. 2 .

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