Fluorescent carbon fiber reinforced corrosion resistant zinc-rich coating for identifying extent of damage and method of making

Abstract

The application discloses a fluorescent carbon fiber reinforced corrosion-resistant zinc-rich coating and a preparation method thereof. The fluorescent carbon fiber reinforced corrosion-resistant zinc-rich coating is prepared by uniformly doping fluorescent carbon fibers into an inorganic zinc-rich anticorrosion coating; and the fluorescent carbon fibers are prepared by growing rare earth organic complexes on the surface of the carbon fibers through a hydrothermal reaction in a reaction kettle. The application endows the carbon fibers with strong fluorescence emission characteristics, and the carbon fibers doped into the inorganic zinc-rich anticorrosion coating can not only improve the corrosion resistance and adhesion, but also intelligently identify the damage degree of the coating through the change of the fluorescence intensity, so that the coating can be used for protecting the steel surface from corrosion and prolonging the service life, and the damage degree of the coating can be accurately and quickly found out through the change of the fluorescence intensity.

Description

Technical Field

[0001] This invention relates to green and environmentally friendly anti-corrosion coating technology, and in particular to a fluorescent carbon fiber reinforced corrosion-resistant zinc-rich coating for identifying the degree of damage and its preparation method. Background Technology

[0002] Currently, water-based anti-corrosion primers, represented by single water-based potassium silicate, sodium silicate, and water-based silica sol, have been applied to some large steel structures. However, these water-based inorganic silica coatings still have some performance problems, mainly in the following aspects: (1) Primers formulated with low-modulus potassium silicate or low-modulus sodium silicate have high brittleness and poor toughness. High-modulus potassium silicate or high-modulus sodium silicate is prone to self-polymerization. The coating storage period is too short, and the transportation and storage process can easily cause the coating to fail and become unusable. (2) The coating construction time is too short. When preparing the coating, a large amount of zinc powder is added. Zinc is a heavy metal, and after the coating is prepared, it is easy to precipitate and cake, causing the coating to fail. Construction is required in a short time, which makes it difficult to achieve high-quality and high-efficiency construction of the coating. (3) Microscopic porosity and poor shielding performance. In typical water-based inorganic zinc-rich coatings, the zinc powder content is as high as 70-80%, far exceeding the critical volume concentration (CPVC) of the filler. At this point, the amount of inorganic silicate binder is insufficient to fill the gaps between the zinc powder particles, resulting in a porous coating. If other topcoats are applied on top of the primer, the probability of bubble formation in the topcoat increases. When the coating is applied in confined spaces or inside materials (such as inside power transmission line steel pipe poles), the difficulty in determining the extent of coating damage increases significantly, making it impossible to assess the coating damage quickly and effectively in a timely manner.

[0003] Prior art document 1 (CN106700680A) discloses a method for preparing a modified waterborne zinc-rich coating. The method involves taking 20-40 parts by weight of potassium silicate, 10-20 parts by weight of potassium methylsilicate, 10-20 parts by weight of emulsified asphalt, 0.5-1 parts by weight of sodium bentonite, 0.2-0.5 parts by weight of tributyl phosphate, 0.2-0.5 parts by weight of sodium polyacrylate, and 28.6-38.6 parts by weight of water. Water and sodium bentonite are added to a mixing tank and stirred until homogeneous. Then, potassium silicate and potassium methylsilicate are added and stirred until homogeneous. Next, emulsified asphalt is added and stirred until homogeneous. Finally, tributyl phosphate and sodium polyacrylate are added and stirred until homogeneous. Finally, flake zinc powder is added and stirred until homogeneous to obtain the coating product. However, the shortcomings of this prior art document 1 are as follows: although adding emulsified asphalt to zinc-rich coatings can improve the overall hydrophobic and waterproof performance and prevent water from penetrating into the coating, emulsified asphalt itself does not have electrical conductivity. This will affect the conductive connection between zinc powder and steel substrate, and some zinc powder cannot completely form a galvanic cell with the substrate, so the cathodic protection effect cannot be fully exerted. Secondly, emulsified asphalt has poor durability and is prone to cracking or even peeling under harsh weather conditions. Most importantly, once this zinc-rich coating fails, the protected metal substrate is often already severely corroded. During the service life of the coating, it is impossible to directly assess its damage level through effective means, and it is also impossible to achieve early warning of coating failure. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a fluorescent carbon fiber-reinforced corrosion-resistant zinc-rich coating for identifying the degree of damage and its preparation method. The carbon fiber is carboxylated, and rare earth complexes are grafted onto the surface of the carbon fiber through a hydrothermal reaction to impart fluorescent properties to the carbon fiber. These properties are then incorporated into the zinc-rich coating to improve its corrosion resistance and simultaneously enable efficient and rapid assessment of the coating's damage level.

[0005] This invention adopts the following technical solution. This invention provides a fluorescent carbon fiber reinforced corrosion-resistant zinc-rich coating for identifying the degree of damage and its preparation method, comprising the following steps:

[0006] Step 1, carbon fiber pretreatment: Polyacrylonitrile-based carbon fiber, acetone and deionized water are added to a reaction vessel to obtain pretreated carbon fiber.

[0007] Step 2, modified carbon fiber: The pretreated carbon fiber obtained in Step 1 is placed in a reaction vessel, titrated with concentrated nitric acid, heated in a water bath, washed and dried to obtain carboxylated carbon fiber.

[0008] Step 3, fluorescent carbon fiber: The carboxylated carbon fiber obtained in step 2, 1,10-phenanthroline, and terephthalic acid are placed in anhydrous ethanol and stirred. Europium nitrate hexahydrate is then fully dissolved in anhydrous ethanol and stirred until dissolved. The two are mixed, heated, stirred, centrifuged, and dried to obtain fluorescent carbon fiber.

[0009] Step 4, preparation of coating: A certain molar ratio of high modulus potassium silicate solution, silicone acrylic emulsion, sodium polyacrylate, fluorescent carbon fiber, hydroxyethyl cellulose, flaky zinc powder, additives (rheology thickener, defoamer, coupling agent) and distilled water are stirred and mixed in a reaction vessel, and filtered to obtain a fluorescent carbon fiber reinforced corrosion-resistant zinc-rich coating with intelligent damage recognition.

[0010] Preferably, step 1 includes:

[0011] Step 1.1: Weigh polyacrylonitrile-based carbon fibers, wash the short-cut carbon fibers with a mixed solution of acetone and deionized water at a volume ratio of 4:1, ultrasonically vibrate for 20-30 minutes, dry at 80-90℃, and keep warm for 6-8 hours.

[0012] Step 1.2: Place the dried carbon fiber into an alumina crucible and hold it in a box furnace heated to 300-500℃ for 4-6 hours.

[0013] Step 1.3: Clean the carbon fiber with a mixed solution of acetone and deionized water, and dry it at 80-90℃ for 8-10 hours.

[0014] Preferably, the carbon fiber in step 1 has a length of 3-4 mm.

[0015] Preferably, step 2 specifically includes:

[0016] The pretreated carbon fiber obtained in step 1 was placed in a beaker and titrated with concentrated nitric acid at a concentration of 60-65%. The mixture was heated in a water bath at 60-80°C for 3-4 hours. The carbon fiber was then washed with a mixed solution of acetone and deionized water until the pH reached 6.9-7.2. The mixture was then dried at 60-80°C for 8-10 hours to obtain carboxylated carbon fiber.

[0017] Preferably, step 3 specifically includes:

[0018] Step 3.1: Weigh the materials according to the molar ratio of carboxylated carbon fiber: 1,10-phenanthroline: terephthalic acid: europium nitrate hexahydrate = 2:3:2:2, and place the carboxylated carbon fiber, terephthalic acid and 1,10-phenanthroline in anhydrous ethanol and stir thoroughly.

[0019] Step 3.2: Dissolve europium nitrate hexahydrate thoroughly in anhydrous ethanol and stir until dissolved. Pour the mixed solution of carboxylated carbon fibers obtained in step 3.1 into the ethanol solution of europium nitrate hexahydrate. Stir with a magnetic stirrer for 6-8 hours under water bath heating at 60-80℃ and centrifuge 3 times at a centrifugation rate of 4000-6000 r / min.

[0020] Step 3.3: Pour the mixed solution obtained in step 3.2 into a polytetrafluoroethylene reactor and keep it in an oven at 80-100℃ for 20-30 hours to obtain carbon fiber with fluorescent properties.

[0021] Preferably, step 4 specifically includes:

[0022] Step 4.1: Add 0.2-0.6% fluorescent carbon fiber and 1.9-3.2% hydroxyethyl cellulose to a container and stir slowly until the hydroxyethyl cellulose is completely dissolved in water. The stirring speed is 700-1000 r / min and the stirring time is 25-35 min to obtain a fluorescent carbon fiber mixed solution.

[0023] Step 4.2: Add 12.3-18.2% high-modulus potassium silicate and 6.9-11.4% silicone-acrylic emulsion to the fluorescent carbon fiber mixed solution obtained in step 4.1, and stir at 1800-2000 r / min for 25-30 min to obtain the base material;

[0024] Step 4.3: Add 0.15-0.62% sodium polyacrylate, 0.15-0.35% defoamer, 0.35-0.85% rheology thickener, and 0.6-1.1% coupling agent to the base material obtained in step 4.2 in sequence, add 40-60% flake zinc powder, stir the obtained mixture at 1800-2000 r / min for 25-35 min, adjust the viscosity of the coating with distilled water, and filter through an 80-mesh standard sieve to obtain a fluorescent carbon fiber reinforced corrosion-resistant zinc-rich coating with intelligent damage identification function;

[0025] Step 4.4: After sandblasting the cleaned metal sample (degreased and derusted), spray the above coating at 293K. Let the coating film dry at room temperature for 20 minutes. After self-curing for 10-15 hours, the coating film will be fully dry, forming a fluorescent carbon fiber reinforced corrosion-resistant zinc-rich coating with high luminescence intensity, strong adhesion, salt spray resistance, water resistance, high temperature resistance, and intelligent damage identification.

[0026] Preferably, the zinc powder in step 4 has a sheet thickness of 0.1-0.3 μm and a sheet diameter of 5-8 μm.

[0027] Preferably, in step 4, hydroxyethyl cellulose (HEC) is used as a dispersant for fluorescent carbon fibers in aqueous solution. When the HEC mass concentration is 1.2-1.8 g / L, the stirring speed is 700-1000 r / min, and the stirring time is 25-35 min, the dispersion rate of fluorescent carbon fibers reaches 95%-98%.

[0028] Preferably, the defoamer in step 4 is an organosilicon defoamer, the main component of which is an organosilicon compound, namely polydimethylsiloxane (PDMS).

[0029] Preferably, the main component of the rheology thickener in step 4 is an aqueous layered aluminosilicate mineral.

[0030] Preferably, the coupling agent in step 4 is a silane coupling agent containing amino and ethoxy functional groups.

[0031] Preferably, the fluorescent carbon fiber reinforced corrosion-resistant zinc-rich coating is prepared by mixing the following components in the following weight ratios, wherein the components and contents are expressed as weight percentages:

[0032]

[0033] Preferably, the fluorescent carbon fiber reinforced corrosion-resistant zinc-rich coating for intelligently identifying the degree of damage is prepared by doping fluorescent carbon fiber into a zinc-rich coating; the fluorescent carbon fiber is prepared by hydrothermal reaction of carbon fiber and rare earth organic complex in a reaction vessel.

[0034] The beneficial effects of this invention are compared with those of the prior art:

[0035] (1) This composite coating can not only improve mechanical properties, but also connect zinc powder particles into a conductive path. This means that carbon fiber can reduce the amount of zinc powder particles used, increase the utilization rate of zinc powder particles, and enhance the adhesion and corrosion resistance of the coating, just like other carbon materials.

[0036] (2) Under ultraviolet excitation, fluorescent carbon fiber has strong fluorescence emission. There is an energy competition absorption relationship between iron ions in the corrosion products and rare earth complexes of fluorescent carbon fiber. The fluorescent carbon fiber will undergo obvious fluorescence quenching, and its fluorescence intensity will decrease or even quench. Fluorescent carbon fiber coating utilizes this characteristic to effectively assess the degree of coating failure after coating damage. Attached Figure Description

[0037] Figure 1 This is a flowchart of a method for preparing a fluorescent carbon fiber reinforced corrosion-resistant zinc-rich coating for identifying the degree of damage, provided by the present invention.

[0038] Figure 2 This is a scanning electron microscope and energy dispersive spectroscopy (EDS) image of a fluorescent carbon fiber reinforced corrosion-resistant zinc-rich coating. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of this invention. The embodiments described in this application are merely some embodiments of this invention, and not all embodiments. Based on the spirit of this invention, other embodiments obtained by those skilled in the art without creative effort are all within the protection scope of this invention.

[0040] like Figure 1 As shown, an embodiment of the present invention provides a method for preparing a fluorescent carbon fiber reinforced corrosion-resistant zinc-rich coating that identifies the degree of damage, comprising the following steps:

[0041] Step 1, carbon fiber pretreatment: Polyacrylonitrile-based carbon fibers, acetone and deionized water are added to a reaction vessel to obtain pretreated carbon fibers.

[0042] In a preferred but non-limiting embodiment of the present invention, step 1 specifically includes:

[0043] Step 1.1: Weigh polyacrylonitrile-based carbon fibers, wash the short-cut carbon fibers with a mixed solution of acetone and deionized water at a volume ratio of 4:1, ultrasonically vibrate for 20-30 minutes, dry at 80-90℃, and keep warm for 6-8 hours.

[0044] Step 1.2: Place the dried carbon fiber into an alumina crucible and hold it in a box furnace heated to 300-500℃ for 4-6 hours.

[0045] Step 1.3: Clean the carbon fiber with a mixed solution of acetone and deionized water, and dry it at 80-90℃ for 8-10 hours.

[0046] In a preferred but non-limiting embodiment of the present invention, the carbon fiber in step 1 has a length of 3-4 mm.

[0047] Step 2, modified carbon fiber: The pretreated carbon fiber obtained in Step 1 is placed in a reaction vessel, titrated with concentrated nitric acid, heated in a water bath, and then washed with a mixed solution of acetone and deionized water. After drying, carboxylated carbon fiber is obtained.

[0048] In a preferred but non-limiting embodiment of the present invention, step 2 specifically includes:

[0049] The pretreated carbon fiber obtained in step 1 was placed in a beaker and titrated with concentrated nitric acid at a concentration of 60-65%. It was then heated in a water bath at 60-80℃ for 3-4 hours. The carbon fiber was then washed with a mixed solution of acetone and deionized water until the pH was 6.9-7.2. It was then dried at 60-80℃ for 8-10 hours for later use, thus obtaining carboxylated carbon fiber.

[0050] Step 3, Fluorescent Carbon Fiber: Carboxylated carbon fiber, 1,10-phenanthroline, and terephthalic acid were placed in anhydrous ethanol and stirred. Europium nitrate hexahydrate was fully dissolved in anhydrous ethanol and stirred until dissolved. Then, the mixed solution of carboxylated carbon fiber was poured into the ethanol solution of dissolved europium nitrate hexahydrate. After heating, stirring, centrifugation, and drying, carbon fiber with fluorescent properties was obtained, and its surface morphology was as follows: Figure 2 As shown.

[0051] In a preferred but non-limiting embodiment of the present invention, step 3 specifically includes:

[0052] Step 3.1: Weigh the materials according to the molar ratio of carboxylated carbon fiber: 1,10-phenanthroline: terephthalic acid: europium nitrate hexahydrate = 2:3:2:2, and place the carboxylated carbon fiber, terephthalic acid and 1,10-phenanthroline in anhydrous ethanol and stir thoroughly.

[0053] Step 3.2: Dissolve europium nitrate hexahydrate thoroughly in anhydrous ethanol and stir until dissolved. Then, pour the mixed solution of carboxylated carbon fibers obtained in step 3.1 into the ethanol solution of europium nitrate hexahydrate. Stir with a magnetic stirrer for 6-8 hours under water bath heating at 60-80℃, and then centrifuge 3 times at a centrifugation rate of 4000-6000 r / min.

[0054] Step 3.3: Pour the mixed solution obtained in step 3.2 into a polytetrafluoroethylene reactor and keep it in an oven at 80-100℃ for 20-30 hours to obtain carbon fiber with fluorescent properties.

[0055] Step 4, preparation of coating: High modulus potassium silicate solution, silicone acrylic emulsion, sodium polyacrylate, fluorescent carbon fiber, hydroxyethyl cellulose, flake zinc powder, additives (rheology thickener, defoamer, coupling agent) and distilled water are stirred and mixed in a reaction vessel, and filtered to obtain fluorescent carbon fiber reinforced corrosion-resistant zinc-rich coating with intelligent damage recognition.

[0056] In a preferred but non-limiting embodiment of the present invention, the sheet thickness of the zinc powder in step 4 is 0.1-0.3 μm and the sheet diameter is 5-8 μm.

[0057] In a preferred but non-limiting embodiment of the present invention, the hydroxyethyl cellulose (HEC) in step 4 is used as a dispersant for fluorescent carbon fibers in an aqueous solution. When the HEC mass concentration is 1.2-1.8 g / L, the stirring speed is 700-1000 r / min, and the stirring time is 25-35 min, the dispersion rate of fluorescent carbon fibers reaches 95%-98%.

[0058] In a preferred but non-limiting embodiment of the present invention, step 4 specifically includes:

[0059] Step 4.1: Add 0.2-0.6% fluorescent carbon fiber and 1.9-3.2% hydroxyethyl cellulose to a container and stir slowly until the hydroxyethyl cellulose is completely dissolved in water. The stirring speed is 700-1000 r / min and the stirring time is 25-35 min to obtain a fluorescent carbon fiber mixed solution.

[0060] Step 4.2: Add 12.3-18.2% high-modulus potassium silicate and 6.9-11.4% silicone-acrylic emulsion to the fluorescent carbon fiber mixed solution obtained in step 4.1, and stir at 1800-2000 r / min for 25-30 min to obtain the base material;

[0061] Step 4.3: Add 0.15-0.62% sodium polyacrylate, 0.15-0.35% defoamer, 0.35-0.85% rheology thickener, and 0.6-1.1% coupling agent to the base material obtained in step 4.2 in sequence, add 40-60% flake zinc powder, stir the obtained mixture at 1800-2000 r / min for 25-35 min, adjust the viscosity of the coating with distilled water, and filter through an 80-mesh standard sieve to obtain a fluorescent carbon fiber reinforced corrosion-resistant zinc-rich coating with intelligent damage identification function;

[0062] Step 4.4: After sandblasting the cleaned metal sample (degreased and derusted), spray the above coating at 293K. The coating will be surface dry after 20 minutes at room temperature and fully dry after 10-15 hours of self-curing. This will form a fluorescent carbon fiber reinforced corrosion-resistant zinc-rich coating with high luminescence intensity, strong adhesion, salt spray resistance, water resistance, and high temperature resistance, which can intelligently identify the degree of damage.

[0063] The implementation of the present invention will be described in detail below with reference to specific embodiments.

[0064] Example 1: Preparation of a fluorescent carbon fiber reinforced corrosion-resistant zinc-rich coating with intelligent damage identification function

[0065] 1. Carbon fiber pretreatment: First, a certain amount of polyacrylonitrile-based carbon fiber is immersed in a mixed solution of acetone and deionized water with a volume ratio of 4:1, ultrasonically vibrated for 25 minutes, and then dried at 85℃ for 7 hours; then the dried carbon fiber is kept at 300℃ in a box furnace for 4 hours; finally, the carbon fiber is washed with acetone aqueous solution and dried at 85℃ for 10 hours.

[0066] 2. Modified carbon fiber: First, the pretreated carbon fiber is titrated with concentrated nitric acid at a concentration of 60-65% and heated in a water bath at 75°C for 3 hours; then the carbon fiber is washed with acetone aqueous solution until pH=7 and dried at 80°C for 10 hours to obtain carboxylated carbon fiber.

[0067] 3. Fluorescent carbon fiber: First, carboxylated carbon fiber, 1,10-phenanthroline, terephthalic acid, and europium nitrate hexahydrate were weighed and dissolved in anhydrous ethanol at a molar ratio of 2:3:2:2. Then, the mixed solution of carboxylated carbon fiber, 1,10-phenanthroline, and terephthalic acid was poured into the ethanol solution of europium nitrate hexahydrate. The mixture was stirred for 8 hours under water bath heating at 80°C, and then centrifuged three times at a centrifuge rate of 5000 r / min. Finally, the above mixed solution was placed in a reaction vessel and kept in an oven at 80°C for 24 hours to obtain fluorescent carbon fiber.

[0068] 4. Coating preparation: 0.2% by weight of fluorescent carbon fiber and 1.9% by weight of hydroxyethyl cellulose were added to a container and stirred slowly until the hydroxyethyl cellulose was completely dissolved in water. Then the stirring speed was increased to 800 r / min and the stirring time was 30 min to obtain a fluorescent carbon fiber mixed solution. 13% high modulus potassium silicate and 7% silicone acrylic emulsion were added to the fluorescent carbon fiber mixed solution and stirred at 2000 r / min for 30 min to obtain the base material. 0.2% sodium polyacrylate, 0.18% defoamer, 0.45% rheology thickener, and 0.87% coupling agent were added to the base material in sequence. Finally, 50% flake zinc powder was added. The obtained mixture was stirred at 2000 r / min for 30 min. The viscosity of the coating was adjusted with distilled water. After filtration through an 80-mesh standard sieve, the fluorescent carbon fiber reinforced corrosion-resistant zinc-rich coating with intelligent damage identification function was obtained.

[0069] The coating is surface dry at room temperature for 20 minutes after application and fully dry after 10 hours. The coating thickness is approximately 15 μm. After a cross-cut adhesion test, the adhesion strength reaches Grade 1. Furthermore, the coating exhibits salt spray resistance for up to 600 hours and remains intact for 24 hours at 400℃. Fluorescence spectroscopy analysis showed the composite coating to have a fluorescence intensity of 780 a.u., which decreased to 526 a.u. after neutral salt spray corrosion.

[0070] Example 2: Preparation of a fluorescent carbon fiber reinforced corrosion-resistant zinc-rich coating with intelligent damage identification function

[0071] 1. Carbon fiber pretreatment: First, a certain amount of polyacrylonitrile-based carbon fiber is immersed in a mixed solution of acetone and deionized water with a volume ratio of 4:1, ultrasonically vibrated for 25 minutes, and then dried at 85℃ for 7 hours; then the dried carbon fiber is kept at 300℃ in a box furnace for 4 hours; finally, the carbon fiber is washed with acetone aqueous solution and dried at 85℃ for 10 hours.

[0072] 2. Modified carbon fiber: First, the pretreated carbon fiber is titrated with concentrated nitric acid at a concentration of 60-65% and heated in a water bath at 75°C for 3 hours; then the carbon fiber is washed with acetone aqueous solution until pH=7 and dried at 80°C for 10 hours to obtain carboxylated carbon fiber.

[0073] 3. Fluorescent carbon fiber: First, carboxylated carbon fiber, 1,10-phenanthroline, terephthalic acid, and europium nitrate hexahydrate were weighed and dissolved in anhydrous ethanol at a molar ratio of 2:3:2:2. Then, the mixed solution of carboxylated carbon fiber, 1,10-phenanthroline, and terephthalic acid was poured into the ethanol solution of europium nitrate hexahydrate. The mixture was stirred for 8 hours under water bath heating at 80°C, and then centrifuged three times at a centrifuge rate of 5000 r / min. Finally, the above mixed solution was placed in a reaction vessel and kept in an oven at 80°C for 24 hours to obtain fluorescent carbon fiber.

[0074] 4. Coating preparation: 0.4% by weight of fluorescent carbon fiber and 2.2% by weight of hydroxyethyl cellulose were added to a container and stirred slowly until the hydroxyethyl cellulose was completely dissolved in water. Then the stirring speed was increased to 800 r / min and the stirring time was 30 min to obtain a fluorescent carbon fiber mixed solution. 15% high-modulus potassium silicate and 9% silicone-acrylic emulsion were added to the fluorescent carbon fiber mixed solution and stirred at 2000 r / min for 30 min to obtain the base material. 0.4% sodium polyacrylate, 0.28% defoamer, 0.65% rheology thickener, and 0.87% coupling agent were added to the base material in sequence. Finally, 45% flake zinc powder was added. The obtained mixture was stirred at 2000 r / min for 30 min. The viscosity of the coating was adjusted with distilled water. After filtration through an 80-mesh standard sieve, the fluorescent carbon fiber reinforced corrosion-resistant zinc-rich coating with intelligent damage identification function was obtained.

[0075] The coating is surface dry at room temperature for 20 minutes after application and fully dry after 10.5 hours. The coating thickness is approximately 20 μm. After a cross-cut adhesion test, the adhesion strength reaches grade 0. Furthermore, the coating is resistant to salt spray for up to 1000 hours and remains intact for 24 hours at 400°C. Fluorescence spectroscopy analysis showed that the composite coating exhibited a fluorescence intensity of 852 a.u., which decreased to 412 a.u. after neutral salt spray corrosion.

[0076] Example 3: Preparation of a fluorescent carbon fiber reinforced corrosion-resistant zinc-rich coating with intelligent damage identification function

[0077] 1. Carbon fiber pretreatment: First, a certain amount of polyacrylonitrile-based carbon fiber is immersed in a mixed solution of acetone and deionized water with a volume ratio of 4:1, ultrasonically vibrated for 25 minutes, and then dried at 85℃ for 7 hours; then the dried carbon fiber is kept at 300℃ in a box furnace for 4 hours; finally, the carbon fiber is washed with acetone aqueous solution and dried at 85℃ for 10 hours.

[0078] 2. Modified carbon fiber: First, the pretreated carbon fiber is titrated with concentrated nitric acid at a concentration of 60-65% and heated in a water bath at 75°C for 3 hours; then the carbon fiber is washed with acetone aqueous solution until pH=7 and dried at 80°C for 10 hours to obtain carboxylated carbon fiber.

[0079] 3. Fluorescent carbon fiber: First, carboxylated carbon fiber, 1,10-phenanthroline, terephthalic acid, and europium nitrate hexahydrate were weighed and dissolved in anhydrous ethanol at a molar ratio of 2:3:2:2. Then, the mixed solution of carboxylated carbon fiber, 1,10-phenanthroline, and terephthalic acid was poured into the ethanol solution of europium nitrate hexahydrate. The mixture was stirred for 8 hours under water bath heating at 80°C, and then centrifuged three times at a centrifuge rate of 5000 r / min. Finally, the above mixed solution was placed in a reaction vessel and kept in an oven at 80°C for 24 hours to obtain fluorescent carbon fiber.

[0080] 4. Coating preparation: 0.6% by weight of fluorescent carbon fiber and 2.8% by weight of hydroxyethyl cellulose were added to a container and stirred slowly until the hydroxyethyl cellulose was completely dissolved in water. Then the stirring speed was increased to 800 r / min and the stirring time was 30 min to obtain a fluorescent carbon fiber mixed solution. 18% high modulus potassium silicate and 11% silicone acrylic emulsion were added to the fluorescent carbon fiber mixed solution and stirred at 2000 r / min for 30 min to obtain the base material. 0.6% sodium polyacrylate, 0.32% defoamer, 0.8% rheology thickener, and 1.08% coupling agent were added to the base material in sequence. Finally, 40% flake zinc powder was added. The obtained mixture was stirred at 2000 r / min for 30 min. The viscosity of the coating was adjusted with distilled water. After filtration through an 80-mesh standard sieve, the fluorescent carbon fiber reinforced corrosion-resistant zinc-rich coating with intelligent damage identification function was obtained.

[0081] The coating is surface dry at room temperature for 20 minutes after application and fully dry after 10.5 hours. The coating thickness is approximately 40 μm. After a cross-cut adhesion test, the adhesion strength reaches grade 0. Furthermore, the coating exhibits salt spray resistance for up to 1440 hours and remains intact for 24 hours at 400°C. Fluorescence spectroscopy analysis showed the composite coating to have a fluorescence intensity of 903 a.u., which decreased to 375 a.u. after neutral salt spray corrosion.

[0082] The beneficial effects of this invention are compared with those of the prior art:

[0083] (1) This composite coating can not only improve mechanical properties, but also connect zinc powder particles into a conductive path. This means that carbon fiber can reduce the amount of zinc powder particles used, increase the utilization rate of zinc powder particles, and enhance the adhesion and corrosion resistance of the coating, just like other carbon materials.

[0084] (2) Under ultraviolet excitation, fluorescent carbon fiber has strong fluorescence emission. There is an energy competition absorption relationship between iron ions in the corrosion products and rare earth complexes of fluorescent carbon fiber. The fluorescent carbon fiber will undergo obvious fluorescence quenching, and its fluorescence intensity will decrease or even quench. Fluorescent carbon fiber coating utilizes this characteristic to effectively assess the degree of coating failure after coating damage.

[0085] This disclosure can be a system, method, and / or computer program product. A computer program product may include a computer-readable storage medium having computer-readable program instructions loaded thereon for causing a processor to implement various aspects of this disclosure.

[0086] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the protection scope of the claims of the present invention.

Claims

1. A method for producing a fluorescent carbon fiber-reinforced corrosion-resistant zinc-rich coating layer that identifies the degree of damage, characterized by, The method comprises the following steps: Step 1: polyacrylonitrile-based carbon fiber, acetone and deionized water are put into a reaction container to obtain pretreated carbon fiber; Step 2: the pretreated carbon fiber obtained in step 1 is placed in a reaction container, titrated with concentrated nitric acid, heated in a water bath, washed and dried to obtain carboxylated carbon fiber; Step 3: the carboxylated carbon fiber obtained in step 2, 1, 10-phenanthroline and terephthalic acid are stirred in anhydrous ethanol, and europium nitrate hexahydrate is fully dissolved in anhydrous ethanol and stirred, then the two are mixed, heated, stirred, centrifuged and dried to obtain fluorescent carbon fiber; Step 4: high modulus potassium silicate solution, silicone-acrylic emulsion, sodium polyacrylate, fluorescent carbon fiber, hydroxyethyl cellulose, flaky zinc powder, additives and distilled water are stirred and mixed in a reaction container, and then filtered to obtain a fluorescent carbon fiber reinforced corrosion resistant zinc-rich coating for intelligent identification of damage degree, wherein the components of the fluorescent carbon fiber reinforced corrosion resistant zinc-rich coating are mixed and prepared in the following weight ratio, and the components and contents are calculated by weight percentage:

2. The preparation method of the fluorescent carbon fiber reinforced corrosion resistant zinc-rich coating for identification of damage degree according to claim 1, wherein Step 1 comprises: Step 1.1: polyacrylonitrile-based carbon fiber is weighed, and the chopped carbon fiber is washed with a mixed solution of acetone and deionized water in a volume ratio of 4:1, ultrasonic oscillation is performed for 20-30 min, and drying is performed at 80-90 ℃ for 6-8 h; Step 1.2: the dried carbon fiber is placed in an alumina crucible and heated to 300-500 ℃ in a box furnace for 4-6 h; Step 1.3: the carbon fiber is washed with a mixed solution of acetone and deionized water, and dried at 80-90 ℃ for 8-10 h.

3. The preparation method of the fluorescent carbon fiber reinforced corrosion resistant zinc-rich coating for identification of damage degree according to claim 2, wherein The length of the carbon fiber in step 1 is 3-4 mm.

4. The preparation method of the fluorescent carbon fiber reinforced corrosion resistant zinc-rich coating for identification of damage degree according to claim 1, wherein Step 2 specifically comprises: The pretreated carbon fiber obtained in step 1 is placed in a beaker, titrated with concentrated nitric acid with a concentration of 60-65%, heated with a water bath at 60-80 ℃ for 3-4 h, then washed with a mixed solution of acetone and deionized water with pH=6.9-7.2, and dried at 60-80 ℃ for 8-10 h to obtain carboxylated carbon fiber.

5. The preparation method of the fluorescent carbon fiber reinforced corrosion resistant zinc-rich coating for identification of damage degree according to claim 1, wherein Step 3 specifically comprises: Step 3.1: carboxylated carbon fiber, terephthalic acid and 1, 10-phenanthroline are weighed according to the molar ratio of carboxylated carbon fiber: 1, 10-phenanthroline: terephthalic acid: europium nitrate hexahydrate = 2:3:2:2, and are fully stirred in anhydrous ethanol; Step 3.2, the europium nitrate hexahydrate is fully dissolved in anhydrous ethanol with sufficient stirring, the mixed solution of carboxylated carbon fiber obtained in step 3.1 is poured into the ethanol solution of dissolved europium nitrate hexahydrate, and the mixture is stirred with a magnetic stirrer at 60-80℃ water bath heating condition for 6-8 h, and centrifuged at a centrifugal speed of 4000-6000 r / min for 3 times; Step 3.3, pour the mixed solution obtained in step 3.2 into a polytetrafluoroethylene reaction kettle, and incubate in an 80-100℃ oven for 20-30 h to obtain carbon fibers with fluorescence properties.

6. The preparation method of the corrosion-resistant zinc-rich coating reinforced by the fluorescent carbon fiber for identifying damage degree according to claim 1, characterized in that, Step 4 specifically comprises: Step 4.1, pour 0.2-0.6% of the fluorescent carbon fiber and 1.9-3.2% of the hydroxyethyl cellulose into a container, and slowly stir until the hydroxyethyl cellulose is completely dissolved in water, the stirring speed is 700-1000 r / min, and the stirring time is 25-35 min to obtain a mixed solution of the fluorescent carbon fiber; Step 4.2, add 12.3-18.2% of the high modulus potassium silicate and 6.9-11.4% of the silicone-acrylate emulsion into the mixed solution of the fluorescent carbon fiber obtained in step 4.1, and stir at a speed of 1800-2000 r / min for 25-30 min to obtain a base material; Step 4.3, sequentially add 0.15-0.62% of the sodium polyacrylate, 0.15-0.35% of the defoaming agent, 0.35-0.85% of the rheological thickening agent, 0.6-1.1% of the coupling agent, and 40-60% of the flaky zinc powder into the base material obtained in step 4.2, stir the obtained mixture at a speed of 1800-2000 r / min for 25-35 min, adjust the viscosity of the coating with distilled water, and filter through an 80-mesh standard sieve to obtain the corrosion-resistant zinc-rich coating reinforced by the fluorescent carbon fiber for identifying damage degree; Step 4.4, spray sand the metal sample cleaned of oil and rust, spray the coating on the metal sample at 293K, let the paint film air dry for 20 min, and let the coating film self-cure for 10-15 h to form the corrosion-resistant zinc-rich coating layer reinforced by the fluorescent carbon fiber for identifying damage degree.

7. The preparation method of the corrosion-resistant zinc-rich coating layer reinforced by the fluorescent carbon fiber for identifying damage degree according to claim 6, characterized in that, the defoaming agent is an organic silicon defoaming agent, and the component of the defoaming agent is an organic silicon compound, i.e., polydimethylsiloxane.

8. The preparation method of the corrosion-resistant zinc-rich coating layer reinforced by the fluorescent carbon fiber for identifying damage degree according to claim 6, characterized in that, the component of the rheological thickening agent is a hydrous layered aluminosilicate mineral.

9. The preparation method of the corrosion-resistant zinc-rich coating layer reinforced by the fluorescent carbon fiber for identifying damage degree according to claim 6, characterized in that, the coupling agent is a silane coupling agent containing amino and ethoxy functional groups.

10. The preparation method of the corrosion-resistant zinc-rich coating layer reinforced by the fluorescent carbon fiber for identifying damage degree according to claim 6, characterized in that, The flaky zinc powder in step 4 has a flake thickness of 0.1-0.3 μm and a flake diameter of 5-8 μm.

11. The method for preparing the fluorescent carbon fiber reinforced corrosion-resistant zinc-rich coating for identifying damage degree according to claim 6, characterized in that, The hydroxyethyl cellulose in step 4 is used as a dispersant for the fluorescent carbon fiber in an aqueous solution, the mass concentration of the HEC is 1.2-1.8 g / L, the stirring speed is 700-1000 r / min, the stirring time is 25-35 min, and the dispersion rate of the fluorescent carbon fiber reaches 95%-98%.

12. A fluorescent carbon fiber reinforced corrosion-resistant zinc-rich coating for identifying damage degree, which is prepared by performing any one of the methods for preparing the fluorescent carbon fiber reinforced corrosion-resistant zinc-rich coating for identifying damage degree according to claims 1-11. The fluorescent carbon fiber reinforced corrosion-resistant zinc-rich coating for identifying damage degree is prepared by doping fluorescent carbon fiber into a zinc-rich coating; the fluorescent carbon fiber is prepared by hydrothermal reaction of carbon fiber and a rare earth organic complex in a reaction kettle.

Images