Metal early corrosion warning filler, preparation method and corrosion-resistant coating prepared by the same

Abstract

The application belongs to the field of material science, and discloses a metal early corrosion early warning filler, a preparation method and a corrosion-resistant coating prepared from the metal early corrosion early warning filler. Compared with organic fluorescent fillers, the filler has the advantages of not being easy to age and long service life; emits near-infrared light, the light in the wavelength range has strong penetration ability on organic matters; the fluorescent filler also has afterglow emission performance, gets rid of the limitation that corrosion detection needs real-time excitation, and solves the problem of excitation light noise. 12 O 40 The solid strong acid is very sensitive to alkaline environment, and has a greater ultraviolet absorption capacity than ZnO. 12 O 40 As a shell, the filler can respond in an environment with pH=8, and realize metal early corrosion early warning. By compounding the filler with epoxy resin polyaniline organic paint, the corrosion resistance of magnesium alloy can be tested, and the early corrosion early warning of magnesium alloy can also be tested.

Description

Technical Field

[0001] This invention relates to the field of materials science, and in particular to a metal early corrosion warning filler, its preparation method, and the corrosion-resistant coating prepared therefrom. Background Technology

[0002] Mg resources account for 2.7% of the total weight of the Earth's crust and 0.13% of seawater; the density of Mg is 1.7 g / cm³. 3 Magnesium alloys are the lightest metallic structural materials used in engineering applications, possessing advantages such as low density, low elastic modulus, high specific strength, and good noise and vibration reduction. With the rapid development of low-cost production, purification, and efficient processing technologies for magnesium alloys, and the urgent need for lightweighting and energy conservation, magnesium alloy research and application have received significant attention in industries such as aerospace and 3C (computers, communications, and consumer electronics). Despite the superior and unique properties and enormous application prospects of magnesium alloys, their poor corrosion resistance limits their large-scale application. Magnesium alloys can be stored in pure water for many years without corrosion, but in Cl... - Rapid corrosion occurs in solution. The thin oxide film formed by Mg in air is loose and porous, with a density coefficient of α=0.79<1, failing to protect the magnesium matrix. Traditional methods have limitations in monitoring the corrosion of small workpieces and are unsuitable for monitoring early corrosion of inaccessible or large workpieces. Therefore, a simple, visual, non-destructive, accurate, sensitive, and real-time fluorescent corrosion monitoring technology is urgently needed. This detection technology uses fluorescent materials as fillers, relying on the property of fluorescence intensity changes caused by the combination of the fluorescent filler with metal ions generated during metal corrosion or by changes in the pH value of the environment due to corrosion to monitor the metal corrosion status. (Metal corrosion generally produces an alkaline or acidic environment. For example, when magnesium and its alloys react: Mg + 2H₂O = Mg(OH)₂ + H₂; when aluminum and its alloys react: Al + 3H₂O = Al(OH)₃ + 3H₂O) + Currently, there is a wide variety of fluorescent fillers available, but they generally suffer from the following shortcomings: fluorescent corrosion fillers are all organic materials, which are prone to aging, have short lifespans, and are not sensitive enough; fluorescence is all visible light, which has limited penetration ability into organic coatings; real-time excitation is required for detection, resulting in excitation light noise and certain limitations; the sensitivity of fluorescent fillers to pH changes is crucial to the sensitivity of monitoring technology.

[0003] There are many diverse and high-performance luminescent materials among inorganic materials, such as ZnGa2O4:0.5Cr. 3+ This luminescent material emits near-infrared light upon ultraviolet excitation and exhibits afterglow emission. It also demonstrates good chemical stability. A fluorescent filler, patent number ZL 202110666866.6, exists, which is based on ZnGa2O4:0.5Cr...3+ The surface is coated with a layer of pH-sensitive ZnO that can block ultraviolet light, forming a fluorescent filler ZnGa2O4:0.5Cr. 3+ @ZnO; However, this fluorescent filler only responds in environments with a pH greater than or equal to 12, and its outer shell dissolves under ultraviolet light to emit near-infrared light. Its pH sensitivity is weak, and there is an urgent need for a simple, visual, non-destructive, accurate, sensitive, and real-time method for monitoring early metal corrosion. A new technology now exists that, if in ZnGa2O4:0.5Cr... 3+ The surface is coated with a layer of H3PW that is pH sensitive and blocks ultraviolet light. 12 O 40 (Its ultraviolet absorption capacity is greater than that of ZnO), the coated composite material ZnGa2O4:0.5Cr 3+ @H3PW 12 O 40 When used as a fluorescent filler, it can overcome the shortcomings of the aforementioned fluorescent fillers. This fluorescent filler is entirely inorganic, making it resistant to aging and long-lasting; it emits near-infrared light, a wavelength range with strong penetrating power into organic materials (fluorescent fillers are typically used dispersed in organic coatings); it also possesses afterglow emission properties, eliminating the need for real-time excitation in corrosion detection and solving the problem of excitation light noise. Furthermore, H3PW... 12 O 40 It is a solid strong acid and is highly sensitive to alkaline environments, which is crucial for improving the sensitivity of the filler. Currently, commonly used corrosion-resistant coatings for magnesium alloys include epoxy resin and polyaniline, etc., using ZnGa2O4:0.5Cr... 3+ @ H3PW 12 O 40 When combined with epoxy resin and polyaniline to prepare coatings, it can improve the corrosion resistance of the coating and also enable early corrosion warning. Summary of the Invention

[0004] To address the shortcomings of existing fluorescent fillers, this invention proposes a metal early corrosion warning filler, its preparation method, and the corrosion-resistant coating prepared therefrom.

[0005] The technical solution of this invention is as follows: A metal early corrosion warning filler has a coating structure, wherein the core material is an inorganic luminescent material that emits light or afterglow when excited by ultraviolet light, and the shell material is H3PW. 12 O 40 .

[0006] The core material is ZnGa2O4:0.5Cr 3+ .

[0007] A method for preparing a metal early corrosion warning filler, wherein the shell material is H3PW.12 O 40 The steps include the following:

[0008] Step 1: Add 4n mol H3PW 12 O 40 Add to deionized water and stir until the solution becomes transparent. Then add 7680 ng PVA to the solution, seal, and heat and stir in a water bath to obtain a sol solution.

[0009] Step 2: Weigh n mol of core material, grind it until it is uniform and fine, disperse it in deionized water, stir and sonicate it to ensure that the core material particles are uniformly dispersed in the deionized water without sedimentation; finally, add the solution to the sol solution in step 1, mix and stir for 1~3 h to obtain a suspension.

[0010] Step 3: Centrifuge, wash, and dry the suspension obtained in Step 2 to obtain powder; after calcination and grinding, prepare the early warning filler for metal corrosion.

[0011] Step 3: The drying temperature is 50~60℃, and the time is 24~48 h.

[0012] Step 3: The calcination atmosphere is air, the temperature is 25~400℃, and the time is 0.5~24 h.

[0013] The preparation process of the core material is as follows:

[0014] Step 1: Weigh 6 nmol of citric acid complexing agent and add it to deionized water, stirring until the solution becomes transparent;

[0015] Step 2: Add Zn(NO3)2 solution, Ga(NO3)3 solution and Cr(NO3)3 solution to the solution obtained in Step 1. The amounts of Zn(NO3)2, Ga(NO3)3 and Cr(NO3)3 added are n mol, 2n mol and 0.01n mol, respectively. Mix the solution and stir until it becomes transparent. Heat it in a water bath and stir until it becomes gel-like.

[0016] Step 3: Place the gelatinous substance obtained in Step 2 into a drying oven and keep it at a certain temperature for 1-5 hours until it is completely carbonized;

[0017] Step 4: Calcine the carbonized material obtained in Step 3 at a certain temperature for 1-8 hours to obtain powder, and then grind it.

[0018] Step 5: Calcine the powder obtained in Step 4 for 1-8 hours at a temperature higher than that in Step 4, and then grind it to obtain the filler core material.

[0019] The water bath heating temperature is room temperature to 90℃.

[0020] Step 3: The heat preservation temperature is room temperature to 400℃.

[0021] The calcination temperature in step four is room temperature to 1000℃.

[0022] A corrosion-resistant coating prepared by a metal early corrosion warning filler is composed of a metal early corrosion warning filler and an epoxy resin polyaniline organic coating.

[0023] Compared with existing technologies, the beneficial effects of this invention are: the early corrosion warning filler for metals is inorganic, and compared with organic fluorescent fillers, it has the advantages of being less prone to aging and having a longer lifespan; the fluorescent filler emits near-infrared light, and light in this wavelength range has strong penetrating power into organic materials, allowing it to be dispersed in organic coatings; the fluorescent filler also possesses afterglow emission performance, overcoming the limitation of real-time excitation required for corrosion detection and solving the problem of excitation light noise. Furthermore, H3PW 12 O 40 It is a solid strong acid and is highly sensitive to alkaline environments, which is crucial for improving the sensitivity of the packing material. H3PW is used. 12 O 40 As the outer shell, ZnGa2O4:0.5Cr 3+ The filler prepared for the core can respond in an environment with pH=8. Combined with epoxy resin polyaniline, it can both improve the corrosion resistance of magnesium alloys and provide early warning of corrosion. However, because H3PW... 12 O 40 It is a solid strong acid, and the core material in this invention is ZnGa2O4:0.5Cr. 3+ Because it is not resistant to strong acids, we use PVA as a binder to bond the two materials, while PVA also provides excellent barrier properties. The existing invention is ZnGa2O4:0.5Cr. 3+ @ZnO, patent number ZL 202110666866.6, is synthesized under alkaline conditions, making it insensitive to alkaline environments. This invention, however, synthesizes it under acidic conditions, exhibiting high sensitivity to alkaline environments. The fluorescent filler synthesized by this method has high coating degree, good density, and easily controllable coating thickness. It is also simple to operate, low in cost, and environmentally friendly. Traditional methods for monitoring metals have many drawbacks, such as being unsuitable for real-time monitoring, low sensitivity, high cost, health hazards, low accuracy, and unsuitability for monitoring large workpieces. Compared to traditional methods, the corrosion-resistant coating for early corrosion warning of magnesium alloys synthesized by this method is simple, visual, non-destructive, accurate, sensitive, and real-time! Attached Figure Description

[0024] Figure 1 is a schematic diagram of the principle of the present invention. Figure 1(a) shows only ZnGa2O4:0.5Cr3+ Under illumination, Figure 1(b) shows ZnGa2O4:0.5Cr3 + H3PW outer coating 12 O 40 Lighting conditions.

[0025] Figure 2(a) shows the existing ZnGa2O4:0.5Cr in Embodiment 1 of the present invention. 3+ SEM scan image.

[0026] Figure 2(b) shows the ZnGa2O4:0.5Cr prepared in Example 1 of this invention. 3+ @ H3PW 12 O 40 SEM scan image.

[0027] Figure 2(c) ZnGa2O4:0.5Cr prepared in Example 1 of the present invention 3+ @ H3PW 12 O 40 Figure 2(c-1) is a SEM scan image; Figure 2(c-2) is a W element distribution map; Figure 2(c-3) is a Zn element distribution map; Figure 2(c-4) is a Ga element distribution map; Figure 2(c-5) is an O element distribution map; Figure 2(c-6) is a P element distribution map.

[0028] Figure 3 The ZnGa2O4:0.5Cr prepared in Example 1 of this invention is... 3+ XRD patterns.

[0029] Figure 4 The ZnGa2O4:0.5Cr prepared in Example 1 of this invention is... 3+ @ H3PW 12 O 40 XRD patterns.

[0030] Figure 5 The ZnGa2O4:0.5Cr prepared in Example 1 of this invention is... 3+ @ H3PW 12 O 40 The excitation and emission spectra.

[0031] Figure 6 The ZnGa2O4:0.5Cr prepared in Example 1 of this invention is... 3+ @ H3PW 12 O 40 The afterglow curve diagram.

[0032] Figure 7 The ZnGa2O4:0.5Cr prepared in Example 1 of this invention is... 3+@ H3PW 12 O 40 Soaking at pH=8 for 20 min and using ZnGa2O4:0.5Cr prepared in Example 2 of this invention. 3+ Real-time near-infrared afterglow images of ZnO soaked for 1 day at pH=9, 10, and 11 under night vision.

[0033] Figure 8 The ZnGa2O4:0.5Cr prepared in Example 1 of this invention is... 3+ @ H3PW 12 O 40 The ZnGa2O4:0.5Cr prepared in Example 2 of this invention 3+ UV absorption spectrum of ZnO.

[0034] Figure 9 The ZnGa2O4:0.5Cr prepared in Example 1 of this invention is... 3+ @ H3PW 12 O 40 The ZnGa2O4:0.5Cr prepared in Example 2 of this invention 3+ The afterglow curve of ZnO after soaking at pH=8 for 20 min and then excitation under 254 nm UV light for 5 min.

[0035] Figure 10 shows the in-situ fluorescence monitoring of magnesium alloy containing fluorescent filler at the pit location. Figure 10(a) is a macroscopic photograph; Figure 10(b) shows the luminescence under real-time excitation by ultraviolet lamp; Figure 10(c) shows the near-infrared afterglow after the ultraviolet lamp is turned off.

[0036] Figure 11 This is a schematic diagram showing the penetration of near-infrared light through epoxy resin polyaniline.

[0037] Figure 12 This is a diagram showing the penetration of near-infrared light through epoxy resin polyaniline films of different thicknesses.

[0038] Figure 13 This is a schematic diagram of an experiment showing the penetration of ultraviolet light through an epoxy resin polyaniline film.

[0039] Figure 14 To enable ultraviolet light to penetrate epoxy resin polyaniline films of varying thicknesses and excite ZnGa2O4:0.5Cr... 3+ The near-infrared afterglow image was then observed.

[0040] Figure 15 For those containing different ZnGa2O4:0.5Cr 3+ The near-infrared luminescence of the epoxy resin film.

[0041] Figure 16For those containing different ZnGa2O4:0.5Cr 3+ The afterglow decay curve of the epoxy resin film.

[0042] Figure 17 shows the cross-sectional scanning morphology of the epoxy resin film. Figure 17(a) shows the epoxy resin polyaniline film; Figure 17(b) shows the film containing 3% ZnGa2O4:0.5Cr. 3+ Epoxy resin polyaniline film.

[0043] Figure 18 shows a mixture containing 3% ZnGa2O4:0.5Cr. 3+ Figure 18(a) shows the cross-sectional morphology of the epoxy resin film and its elemental distribution diagram; Figure 18(b) shows the C elemental distribution diagram; Figure 18(c) shows the O elemental distribution diagram; Figure 18(d) shows the Zn elemental distribution diagram; Figure 18(e) shows the Ga elemental distribution diagram.

[0044] Figure 19 Contains ZnGa2O4:0.5Cr 3+ @ H3PW 12 O 40 Near-infrared luminescence of epoxy resin polyaniline film.

[0045] Figure 20 Contains ZnGa2O4:0.5Cr 3+ @ H3PW 12 O 40 Afterglow decay curve of epoxy resin polyaniline film.

[0046] Figure 21 Contains ZnGa2O4:0.5Cr 3+ @ H3PW 12 O 40 Afterglow photograph of epoxy resin polyaniline film after soaking in an environment of pH=8 for 1 hour.

[0047] Figure 22 shows a structure containing ZnGa2O4:0.5Cr. 3+ @ H3PW 12 O 40 Figure 22(a) shows the cross-sectional morphology and elemental distribution of an epoxy resin polyaniline film after immersion in an environment at pH=8 for 1 hour. Figures 22(b)-22(d) This is a distribution map of elements. Detailed Implementation

[0048] The specific embodiments of the present invention are described in detail below with reference to the technical solutions and accompanying drawings.

[0049] The core materials include, but are not limited to, ZnGa2O4:0.5Cr 3+ .

[0050] Mechanism of action (core material is ZnGa2O4:0.5Cr) 3+ For example): ZnGa2O4:0.5Cr 3+ @ H3PW 12 O 40 It is a fluorescent filler with a coated structure, consisting of a core material ZnGa2O4:0.5Cr. 3+ and shell material H3PW 12 O 40 Composition, H3PW 12 O 40 It is a solid strong acid, extremely potent, and readily reacts with alkalis; simultaneously, this substance can block ultraviolet light. When no corrosion occurs, ultraviolet light excites the fluorescent filler, due to the shell material H3PW... 12 O 40 The shell effectively blocks ultraviolet light, allowing only a small portion of it to penetrate and affect the core material ZnGa2O4:0.5Cr. 3+ Excitation occurs, resulting in weak or even undetectable near-infrared light intensity. When corrosion occurs, the pH value of the environment surrounding the metal changes, affecting the shell material H3PW. 12 O 40 Dissolution occurs; the core material is ZnGa2O4:0.5Cr. 3+ As the material is gradually exposed, it emits strong near-infrared light under ultraviolet excitation, and this near-infrared light can still be observed after the excitation source is turned off. Light in this wavelength range has strong penetrating power to organic matter, allowing fluorescent fillers to be dispersed within organic coatings. Therefore, the corrosion status of magnesium alloys can be detected by monitoring changes in the fluorescence intensity of the fluorescent filler. Epoxy resin polyaniline functional coatings are traditional corrosion-resistant coatings for magnesium alloys and can prevent corrosion. Combining these two methods can effectively achieve early corrosion warning for magnesium alloys. When the magnesium alloy is not corroded, after ultraviolet excitation, due to H3PW... 12 O 40 The coating shields against ultraviolet radiation, so it does not generate near-infrared warning signals. However, when early corrosion occurs in the magnesium alloy, the pitting environment beneath the coating becomes alkaline, producing OH-. - This will dissolve the H3PW of the probe. 12 O 40 The outer shell exposes ZnGa2O4:0.5Cr. 3+ Therefore, when excited by ultraviolet light, near-infrared warning signals will appear at the location of the corrosion pit, thus realizing early warning of corrosion of magnesium alloy.

[0051] All chemical reagents used in the examples of this invention are analytical grade products; XRD phase analysis was performed using an X'Pert Pro X-ray diffractometer (model PW3040 / 60); morphology observation and analysis were performed using a JSM-7001F JEOL field emission scanning electron microscope; emission spectra were measured using an FP8600 fluorescence spectrophotometer; and afterglow performance was measured using a Fluorolog modular fluorescence spectrophotometer.

[0052] Example 1

[0053] 2.52168 g of citric acid complexing agent was added to 20 mL of purified water and stirred for 30 min until the solution became transparent. 2 mL of 1 mol / L Zn(NO3)2 solution, 10 mL of 0.4 mol / L Ga(NO3)3 solution, and 0.2 mL of 0.1 mol / L Cr(NO3)3 solution were weighed and added to the previously transparent solution. The solution was mixed and stirred until transparent. The resulting solution was then placed in a water bath at 90°C and heated with stirring for 2 h to evaporate the water to a certain extent. The solution was then transferred to a small crucible and evaporated to dryness until it became gelatinous. The resulting gelatinous substance was then placed in a drying oven and kept at 200°C for 2 h until completely carbonized. The resulting carbonized substance was calcined at 1000°C with oxygen for 4 h, then ground, and then calcined at 1200°C for 4 h. After grinding, the filler core material ZnGa2O4:0.5Cr was obtained. 3+ .

[0054] Dissolve 5.35g of phosphotungstic acid in 45mL of purified water to prepare a phosphotungstic acid solution; stir for 30min until the solution becomes transparent, then add 3.57g of PVA to the solution, seal with plastic wrap, and heat and stir in a water bath (temperature 60℃) for 2h to obtain a mixed sol solution; weigh out the core material ZnGa2O4:0.5Cr 3+ 0.1 g was ground until uniform and fine; then it was dispersed in 5 mL of deionized water, stirred and sonicated to ensure uniform dispersion of the core material particles in the solution without sedimentation; finally, this solution was added to the prepared mixed sol solution, and mixed and stirred for 2 h to obtain a suspension; after stirring, the suspension was centrifuged to obtain the bottom precipitate, dried at 60℃ for 24 h, and then the obtained powder was calcined at 400℃ for 8 h in air atmosphere. Finally, the fluorescent filler ZnGa2O4:0.5Cr was obtained. 3+ @ H3PW 12 O 40 .

[0055] Figure 2(a) shows the core material ZnGa2O4:0.5Cr. 3+ The scanning morphology of the particles, with a size ranging from 0.5 to 4.0 μm and a smooth surface, is shown in the XRD pattern. Figure 3 As shown in Figure 2(b), the fluorescent filler ZnGa2O4:0.5Cr is shown. 3+ @ H3PW 12 O 40 The scanning morphology image shows that, due to ZnGa2O4:0.5Cr 3+ H3PW 12 O 40 The coating results in a rough surface. Figure 2(c) shows the fluorescent filler ZnGa2O4:0.5Cr. 3+ @ H3PW 12 O 40 The elemental distribution diagram shows that W is distributed in ZnGa2O4:0.5Cr. 3+ The surface of ZnGa2O4:0.5Cr was confirmed. 3+ H3PW 12 O 40 Encapsulation. Its XRD pattern is as follows: Figure 4 As shown, it is proven to be ZnGa2O4:0.5Cr 3+ and H3PW 12 O 40 Biphasic. Figure 5 ZnGa2O4:0.5Cr 3+ and ZnGa2O4:0.5Cr 3+ @ H3PW 12 O 40 The excitation and emission spectra under 254 nm ultraviolet light irradiation, due to H3PW 12 O 40 The effect of blocking ultraviolet rays, ZnGa2O4:0.5Cr 3+ @ H3PW 12 O 40 The emission intensity of near-infrared light is significantly reduced. Figure 6 ZnGa2O4:0.5Cr 3+ and ZnGa2O4:0.5Cr 3+ @ H3PW 12 O 40 The afterglow curve after irradiation with 254 nm ultraviolet light for 5 minutes is also due to H3PW. 12 O 40 The effect of blocking ultraviolet rays, ZnGa2O4:0.5Cr 3+ @ H3PW 12 O 40 The intensity of the near-infrared afterglow is reduced.

[0056] Example 2

[0057] Dissolve 0.68 g of zinc acetate dihydrate in 100 mL of anhydrous ethanol to prepare a zinc acetate ethanol solution; add 0.25 g of sodium hydroxide to a mixed solution of anhydrous ethanol and deionized water (25 mL of anhydrous ethanol and 10 mL of deionized water) to prepare a sodium hydroxide solution. Weigh out the available ZnGa₂O₄:0.5Cr... 3+ 0.11 g of particles were ground until uniform and fine; then dispersed in the above zinc acetate ethanol solution, stirred and sonicated to achieve a ZnGa2O4:0.5Cr content. 3+ The particles are uniformly dispersed in the solution without sedimentation. The solution contains ZnGa2O4:0.5Cr. 3+ The suspension was heated and stirred in a water bath (60℃), and then the prepared sodium hydroxide solution was slowly added. After the addition was complete, the container containing the suspension was sealed, and heating and stirring continued for 4 hours. After heating and stirring, the suspension was centrifuged to obtain the bottom precipitate, which was washed twice with anhydrous ethanol and dried at 50℃ for 24 hours. The resulting powder was then calcined at 200℃ for 2 hours in air. Finally, the fluorescent probe ZnGa2O4:0.5Cr was obtained. 3+ @ZnO.

[0058] Example 3

[0059] Add an appropriate amount of ammonia water to a beaker containing deionized water, and adjust the pH by adding ammonia water while stirring. Prepare 50 mL alkaline solutions with pH values ​​of 8, 9, 10, and 11 respectively. Take the ZnGa2O4:0.5Cr prepared in Example 1 of this invention... 3+ @ H3PW 12 O 40 The ZnGa2O4:0.5Cr prepared in Example 2 of this invention 3+ 1g of each of ZnO was added to alkaline solutions of different pH values ​​and soaked and stirred. The resulting suspension was sealed in a container and stirred evenly for 20 min. The suspension was centrifuged at 500 r / min to obtain the bottom precipitate, washed twice with anhydrous ethanol, and dried at 50℃ for 24 h. The resulting powder was then ground evenly.

[0060] Figure 7 ZnGa2O4:0.5Cr 3+ @ H3PW 12 O 40 Soaking at pH=8 for 20 min with ZnGa2O4:0.5Cr 3+ Near-infrared real-time afterglow images of ZnO soaked for 1 day at pH=9, 10, and 11 under night vision, ZnGa2O4:0.5Cr 3+@ZnO, when soaked for one day at a pH of 12 or less, shows almost no near-infrared emission. However, ZnGa2O4:0.5Cr... 3+ @H3PW 12 O 40 Immersion at pH=8 for 20 minutes will result in noticeable near-infrared light emission; Figure 8 The ZnGa2O4:0.5Cr prepared in Example 1 of this invention 3+ @ H3PW 12 O 40 The ZnGa2O4:0.5Cr prepared in Example 2 of this invention 3+ The UV absorption spectrum of ZnO clearly shows H3PW. 12 O 40 Its ultraviolet absorption capacity is much greater than that of ZnO; Figure 9 The ZnGa2O4:0.5Cr prepared in Example 1 of this invention 3+ @ H3PW 12 O 40 The ZnGa2O4:0.5Cr prepared in Example 2 of this invention 3+ The afterglow curve of ZnO after soaking at pH=8 for 20 min and then excitation under 254 nm UV light for 5 min is shown. The ZnGa2O4:0.5Cr composition can be observed. 3+ @ H3PW 12 O 40 After soaking for 20 minutes at pH=8, obvious afterglow emission could be observed under 254nm ultraviolet light, while ZnGa2O4:0.5Cr 3+ @ZnO is almost non-existent; this further illustrates the relationship between ZnGa2O4:0.5Cr 3+ @H3PW 12 O 40 The filler is highly sensitive to alkaline environments, much more so than ZnGa2O4:0.5Cr. 3+ @ZnO.

[0061] Example 4

[0062] Weigh 0.9 g of n-butanol and 2.1 g of xylene into a beaker, then weigh 10 g of epoxy resin polyaniline into the beaker. Stir evenly for 10 min. Place the mixture in a drying oven and keep it at 50℃ for 10 min to remove bubbles generated by stirring. Add ZnGa2O4:0.5Cr 3+ @ H3PW 12 O 40 Particles and ZnGa2O4:0.5Cr 3+The granules (1.5%, 3%, 5%, 7%, 10%) were used as fillers and ultrasonically stirred for 15 min to uniformly disperse the fillers in the epoxy resin polyaniline. The mixture was then placed in a drying oven and kept at 50℃ for 10 min to remove air bubbles generated during stirring. 6 g of curing agent was then added and stirred for 10 min. The mixture was again placed in a drying oven and kept at 50℃ for 15 min to remove air bubbles. The gel-like mixture was then coated onto a non-woven fabric and dried in a drying oven at 50℃ for 24 h. Approximately 2 ml of NaCl solution containing 1% filler was directly added to the surface of a magnesium alloy after the oxide film had been removed using a dropper. Since magnesium alloy is highly corroded in NaCl solution, obvious black pits appeared on the surface of the magnesium alloy within just one day. Real-time excitation with a UV lamp revealed bright near-infrared emission at the pits, and a bright near-infrared afterglow remained at the location after the UV lamp was turned off, as shown in Figure 10.

[0063] ZnGa2O4:0.5Cr 3+ The material is loaded into a circular mold, and ZnGa2O4:0.5Cr is first excited using a UV lamp. 3+ The material is then covered with an epoxy resin polyaniline film over a circular mold containing the material. Figure 11 (As shown in the schematic diagram), it was found that even after covering with approximately 4 layers (4 mm thick) of epoxy resin film, the near-infrared light could still be observed, as... Figure 12 As shown, this indicates that near-infrared light can penetrate the epoxy resin polyaniline film. The epoxy resin polyaniline film was used to coat a substrate containing ZnGa2O4:0.5Cr. 3+ On the circular mold of the material, it is then excited with an ultraviolet lamp ( Figure 13 (See schematic diagram) Excitation was performed on it, and observation revealed that in ZnGa2O4:0.5Cr... 3+ Even after covering the material with approximately four layers (4 mm thick) of epoxy resin polyaniline film, a UV lamp can still excite ZnGa2O4:0.5Cr. 3+ Materials, such as Figure 14 As shown, near-infrared light signals can be observed.

[0064] To explore the optimal doping concentration of the probe in the coating, the following experiment was conducted: first, ZnGa2O4:0.5Cr... 3+ ZnGa2O4 was added to epoxy resin polyaniline as a filler, and the near-infrared afterglow signal was observed to determine the ZnGa2O4:0.5Cr content. 3+ The optimal doping amount was determined, and then the optimal doping ratio was ZnGa2O4:0.5Cr. 3+ Based on the amount of ZnGa2O4:0.5Cr, then determine the ZnGa2O4:0.5Cr content. 3+ @ H3PW 12 O 40The amount. For example... Figure 15 For samples containing different amounts of ZnGa2O4:0.5Cr 3+ The near-infrared luminescence of epoxy resin polyaniline films was observed, specifically in films containing 1.5% ZnGa2O4:0.5Cr. 3+ The epoxy resin polyaniline film exhibits very weak near-infrared afterglow, while the film containing 3% ZnGa2O4:0.5Cr... 3+ and containing 5% ZnGa2O4:0.5Cr 3+ The epoxy resin polyaniline exhibits uniform and distinct near-infrared luminescence, but due to excessive filler content, including 7% ZnGa2O4:0.5Cr... 3+ and containing 10% ZnGa2O4:0.5Cr 3+ Although epoxy resin polyaniline emits strong near-infrared light, it also leads to uneven light emission. Figure 16 For those containing different ZnGa2O4:0.5Cr 3+ The afterglow decay curve of the epoxy resin polyaniline film showed that as the afterglow decay of ZnGa2O4:0.5Cr increased, the afterglow decay of ZnGa2O4:0.5Cr decreased. 3+ With increasing content, the afterglow gradually increases, consistent with the near-infrared afterglow phenomenon observed above. Figure 17 shows the cross-sectional scanning morphology of epoxy resin polyaniline film, (a) epoxy resin polyaniline film, (b) film containing 3% ZnGa2O4:0.5Cr 3+ Epoxy resin polyaniline film. Figure 18 shows a film containing 3% ZnGa2O4:0.5Cr. 3+ Cross-sectional morphology diagram and elemental distribution diagram of epoxy resin film.

[0065] Example 5

[0066] ZnGa2O4:0.5Cr coated with different concentrations 3+ @ H3PW 12 O 40 The composite materials (samples S2, S4, and S5) were doped into the epoxy resin polyaniline of Example 4. Figure 19 As shown, it contains ZnGa2O4:0.5Cr 3+ @ H3PW 12 O 40 Near-infrared afterglow image of epoxy resin polyaniline film composite material, due to H3PW of sample S2 12 O 40 The coating effect was poor, so weak near-infrared light could still be observed when it was incorporated into epoxy resin polyaniline. However, in samples S4 and S5, due to H3PW... 12 O 40 The coating effect is good, so almost no near-infrared light is visible after incorporating epoxy resin polyaniline. For example... Figure 20As shown, it contains ZnGa2O4:0.5Cr 3+ @ H3PW 12 O 40 The afterglow decay curve of the epoxy resin polyaniline film of the composite material shows a pattern consistent with that observed in near-infrared afterglow luminescence photographs.

[0067] To explore the presence of ZnGa2O4:0.5Cr 3+ @ H3PW 12 O 40 The epoxy resin film is sensitive to pH conditions. The coating containing sample S4 was immersed in a NaCl solution at pH 8, and the presence of near-infrared light signals was observed. The results showed that the near-infrared afterglow signal gradually increased with immersion time. Figure 21 As shown. This may be due to the functional coating being treated with OH... - After soaking in the solution, OH - Diffusion occurs within the membrane, and when the membrane reaches saturation with water, a large amount of OH- will be released. - Entering, at this time, the OH- enters - It will dissolve the H3PW probe. 12 O 40 The outer shell exposes ZnGa2O4:0.5Cr. 3+ The core then generates a near-infrared light warning signal. Figure 22 shows a structure containing ZnGa2O4:0.5Cr. 3+ @ H3PW 12 O 40 Cross-sectional morphology and elemental distribution of epoxy resin polyaniline film after immersion in pH=8 environment for 1 hour.

Claims

1. A metal early corrosion warning filler, characterized in that, The early corrosion warning filler for metals has a coating structure, wherein the core material is an inorganic luminescent material that emits light or afterglow when excited by ultraviolet light, and the shell material is H3PW. 12 O 40 The core material is ZnGa2O4:0.5Cr. 3+ PVA is used as the binder for both the core and shell materials.

2. A method for preparing the early warning packing for metal corrosion as described in claim 1, characterized in that, The shell material is H3PW. 12 O 40 Its characteristic is that it includes the following steps: Step 1: Add 4n mol H3PW 12 O 40 Add to deionized water and stir until the solution becomes transparent. Then add 7680n g of PVA to the solution, seal, and heat and stir in a water bath to obtain a sol solution. Step 2: Weigh n mol of core material, grind it until it is uniform and fine, disperse it in deionized water, stir and sonicate it to ensure that the core material particles are uniformly dispersed in the deionized water without sedimentation; finally, add the solution to the sol solution in step 1, mix and stir for 1~3 h to obtain a suspension. Step 3: Centrifuge, wash, and dry the suspension obtained in Step 2 to obtain powder; after calcination and grinding, prepare the early warning filler for metal corrosion.

3. The method for preparing the early warning packing for metal corrosion according to claim 2, characterized in that, Step 3: The drying temperature is 50~60℃, and the time is 24~48 h.

4. The method for preparing the early warning packing for metal corrosion according to claim 2, characterized in that, Step 3: The calcination atmosphere is air, the temperature is 25~400℃, and the time is 0.5~24 h.

5. The method for preparing the early warning packing for metal corrosion according to any one of claims 2-4, characterized in that, The preparation process of the core material is as follows: Step 1: Weigh 6 nmol of citric acid complexing agent and add it to deionized water, stirring until the solution becomes transparent; Step 2: Add Zn(NO3)2 solution, Ga(NO3)3 solution and Cr(NO3)3 solution to the solution obtained in Step 1. The amounts of Zn(NO3)2, Ga(NO3)3 and Cr(NO3)3 added are n mol, 2n mol and 0.01n mol, respectively. Mix the solution and stir until it becomes transparent. Heat it in a water bath and stir until it becomes gel-like. Step 3: Place the gelatinous substance obtained in Step 2 into a drying oven and keep it at a certain temperature for 1-5 hours until it is completely carbonized; Step 4: Calcine the carbonized material obtained in Step 3 at a certain temperature for 1-8 hours to obtain powder, and then grind it. Step 5: Calcine the powder obtained in Step 4 for 1-8 hours at a temperature higher than that in Step 4, and then grind it to obtain the filler core material.

6. The method for preparing the early warning packing for metal corrosion according to claim 5, characterized in that, The water bath heating temperature is room temperature to 90℃.

7. The method for preparing the early warning packing for metal corrosion according to claim 6, characterized in that, Step 3: The heat preservation temperature is room temperature to 400℃.

8. The method for preparing the early warning packing for metal corrosion according to claim 7, characterized in that, The calcination temperature in step four is room temperature to 1000℃.

9. A corrosion-resistant coating prepared from the early warning filler for metal corrosion as described in claim 1, characterized in that, The corrosion-resistant coating consists of a metal early corrosion warning filler and an epoxy resin polyaniline organic coating.

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