A thermally irreversible self-sensing color-changing anticorrosive coating for thermal fault detection and a preparation method thereof

Abstract

The application relates to a thermally irreversible self-sensing color-changing anticorrosive coating for thermal fault detection and a preparation method thereof, and relates to the field of anticorrosive materials. The application aims at solving the problems of unstable color-changing performance, poor stability and color-changing durability of existing thermal color-changing materials. The application comprises the following steps: (1) adding nickel ammonium sulfate hexahydrate into an organic solvent A to obtain a mixed solution; then adding a colorant and a chromogenic agent to form a colored mixed solution; finally adding ammonium ferrous sulfate hexahydrate, uniformly mixing through ultrasonic, and vacuum drying to obtain a color-changing filler in a gel state; (2) adding graphene oxide into a N,N-dimethylformamide dispersion solution of nano titanium dioxide, and then preparing a titanium dioxide modified graphene oxide anticorrosive filler through a hydrothermal method; and (3) adding the color-changing filler into an epoxy resin emulsion to form a colored emulsion; slowly adding the modified graphene oxide anticorrosive filler to obtain an anticorrosive emulsion; and adding a film-forming aid and a curing agent to obtain the thermally irreversible self-sensing color-changing anticorrosive coating.

Description

Technical Field

[0001] This invention relates to the field of anti-corrosion materials technology, and more specifically, to a thermo-induced irreversible self-sensing color-changing anti-corrosion coating for thermal fault detection and its preparation method. Background Technology

[0002] With the expansion of industrial scale, equipment such as metal pipelines and power transmission lines that bear high temperatures and pressures often fail due to corrosion, aging, and other factors during operation, with thermal failures being one of the most common. Currently, due to limitations in technology and environmental conditions, factories and power systems still rely primarily on manual methods for detecting thermal failures. Traditional manual detection methods suffer from high labor costs, limited detection range, and poor operating environments, making it difficult to reflect the temperature status of pipelines in a timely manner and posing certain safety hazards. Developing thermochromic anti-corrosion coatings can change color according to the temperature changes of pipelines, achieving the purpose of thermal failure detection and avoiding misjudgments and omissions caused by manual detection; at the same time, the coating can also provide corrosion protection for metal pipelines, extending their service life. The color-changing principle of irreversible thermochromic materials mainly includes: 1) The molecular structure of organic dyes changes after heating, resulting in a color change. Among these, benzoquinone dyes exhibit several color changes due to the oxidation of the quinone groups (-C=O) in their molecules, reducing them to alcohol groups (-CHOH). These dyes suffer from poor stability and color-changing durability. 2) Polymer color-changing materials undergo redox reactions upon heating, resulting in color changes. For example, thermochromic polyimide exhibits sensitive color-changing effects but suffers from poor environmental tolerance, being susceptible to chemicals, strong acids, and strong alkalis, which diminishes its color-changing performance. 3) Metal oxide color-changing materials such as chromium oxide, tungsten oxide, and iron oxide undergo color changes at higher temperatures due to the diffusion of metal ions and changes in their crystal structure. However, some metal oxides are toxic and harmful, causing environmental pollution. Furthermore, the development of thermochromic anti-corrosion coatings must consider the chemical reactions between the color-changing medium and the metal substrate beneath the coating to avoid exacerbating metal corrosion. Summary of the Invention

[0003] The technical problem to be solved by this invention is:

[0004] Existing thermochromic materials suffer from problems such as unstable color-changing performance, poor stability and color-changing durability, as well as the use of toxic and harmful metal oxides that easily cause environmental pollution.

[0005] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0006] This invention provides a method for preparing a thermo-induced irreversible self-sensing color-changing anti-corrosion coating for thermal fault detection, comprising the following steps:

[0007] (1) Preparation of thermo-induced irreversible self-sensing color-changing filler;

[0008] ① Add nickel ammonium sulfate hexahydrate to organic solvent A and stir until homogeneous to obtain a mixture;

[0009] ②Then add coloring agent and color-developing agent to the mixture to form a colored mixture;

[0010] ③ Add ferrous ammonium sulfate hexahydrate to the colored mixture, mix evenly by ultrasonication, and vacuum dry to a gel-like state to obtain the color-changing filler;

[0011] (2) Add graphene oxide to the N,N-dimethylformamide dispersion of nano-titanium dioxide, and then prepare titanium dioxide modified graphene oxide anticorrosive filler by hydrothermal method.

[0012] (3) Preparation of thermo-induced irreversible self-sensing color-changing anti-corrosion coating;

[0013] ① Add the color-changing filler prepared in step (1) to the epoxy resin emulsion and stir thoroughly to form a colored emulsion;

[0014] ② Slowly add the modified graphene oxide anticorrosive filler prepared in step (2) to the colored emulsion, and continue to stir and mix to obtain the anticorrosive emulsion;

[0015] ③ Add film-forming aid and curing agent to the anti-corrosion emulsion, mix well and obtain a thermo-induced irreversible self-sensing color-changing anti-corrosion coating.

[0016] Further, the organic solvent A mentioned in step (1)① is xylene, the colorant mentioned in step (1)② is cobalt oxide, and the colorant is crystal violet.

[0017] Furthermore, in step (1)②, the mass ratio of cobalt oxide to nickel ammonium sulfate hexahydrate is 0.5:2, and the mass ratio of crystal violet to nickel ammonium sulfate hexahydrate is 0.5:2; in step (1)③, the mass ratio of ferrous ammonium sulfate hexahydrate to nickel ammonium sulfate hexahydrate is (1~2.5):4.

[0018] Furthermore, the stirring time in step (1)① is 2 to 6 hours, the ultrasonic time in step (1)③ is 2 to 6 hours, and the vacuum drying time in step (1)③ is 2 to 6 hours.

[0019] Furthermore, the preparation of titanium dioxide-modified graphene oxide anticorrosion filler in step (2) includes the following process:

[0020] ① Graphene oxide was prepared using the Hummers method;

[0021] ② Add nano-titanium dioxide to N,N-dimethylformamide, stir and disperse evenly to obtain a dispersion of nano-titanium dioxide in N,N-dimethylformamide;

[0022] ③ Add graphene oxide to the N,N-dimethylformamide dispersion of nano-titanium dioxide to obtain a mixed dispersion;

[0023] ④ Pour the above mixed dispersion into a reaction vessel for hydrothermal reaction, then vacuum dry, ball mill, and wash to obtain modified graphene oxide anticorrosive filler.

[0024] Furthermore, in step (2)③, the mass ratio of graphene oxide to nano-titanium dioxide is (1.5~3):1.

[0025] Furthermore, the preparation of graphene oxide using the Hummers method described in step two① includes the following process:

[0026] Flake graphite and sodium nitrate were added to concentrated sulfuric acid according to the mass fraction. The mixture was allowed to stand and mix evenly under ice-water bath conditions. Phosphoric acid was added and stirred. Potassium permanganate was slowly added while controlling the temperature below 4°C. The reaction was allowed to proceed for 1 hour. Then, the reaction was continued at 40°C and 95°C for 1 hour each. Deionized water was added and the mixture was allowed to stand. Hydrogen peroxide was slowly added dropwise to obtain a suspension. After the reaction was completed, the mixture was centrifuged, and the precipitate was washed until neutral. The precipitate was then vacuum dried, ground, and sieved to obtain graphene oxide powder.

[0027] Further, in step (3), the mass ratio of the color-changing filler to the epoxy resin is 1 to 2.5:10, and the mass ratio of the modified graphene oxide to the epoxy resin is 0.1 to 0.5:10.

[0028] Furthermore, the film-forming aids in step (3)③ include defoamers and leveling agents, and the mass ratio of the film-forming aids to the epoxy resin is 0.1 to 1:10.

[0029] This invention provides a thermo-irreversible self-sensing color-changing anti-corrosion coating for thermal fault detection, wherein the thermo-irreversible self-sensing color-changing anti-corrosion coating is prepared by the preparation method described in any of the above technical solutions.

[0030] Compared with the prior art, the beneficial effects of the present invention are:

[0031] The thermally induced irreversible self-sensing color-changing anti-corrosion coating for thermal fault detection provided by this invention can self-sensitize and change color according to temperature changes. It starts as a deep blue color (at room temperature of 24℃) before heating, begins to change color at 258℃, and completely turns yellow at 264℃, with a color change time of approximately 3 minutes. The starting temperature for color change is moderate, meeting the warning requirements for actual abnormal temperatures, and the color change is obvious and highly recognizable. This invention uses nano-titanium dioxide modified graphene oxide anti-corrosion filler, which has superior physical strength and dispersibility in the resin, effectively resisting the intrusion of corrosive media such as water, sodium ions, and chloride ions, thus improving the coating's anti-corrosion ability. It is low in cost, has good environmental adaptability, and effectively enhances the coating's service life. Attached Figure Description

[0032] Figure 1 Images of the thermo-induced irreversible self-sensing color-changing anti-corrosion coating in an embodiment of the present invention at different temperatures;

[0033] Figure 2 The morphology of the thermo-induced irreversible self-sensory color-changing anti-corrosion coating in the embodiment of the present invention during the heating process;

[0034] Figure 3 Fourier transform infrared spectra of the thermo-induced irreversible self-sensory color-changing filler, nickel ammonium sulfate, crystal violet and ferrous ammonium sulfate in the embodiments of the present invention;

[0035] Figure 4 Raman spectra of the thermo-induced irreversible self-sensory color-changing filler, nickel ammonium sulfate, crystal violet and ferrous ammonium sulfate in the embodiments of the present invention;

[0036] Figure 5 The images show the XRD patterns of graphene oxide and modified graphene oxide anti-corrosion fillers used in the embodiments of the present invention. Detailed Implementation

[0037] To enable those skilled in the art to better understand the present invention, exemplary embodiments or examples of the present invention will be described below in conjunction with the accompanying drawings. Obviously, the described embodiments or examples are merely some, not all, of the embodiments or examples of the present invention. All other embodiments or examples obtained by those skilled in the art based on the embodiments or examples of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0038] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0039] Example 1: A method for preparing a thermo-induced irreversible self-sensing color-changing anti-corrosion coating for thermal fault detection, comprising the following steps:

[0040] (1) Preparation of thermo-induced irreversible self-sensing color-changing filler;

[0041] ① Place 50 mL of xylene in a 100 mL beaker, add 2 g of nickel ammonium sulfate hexahydrate, and stir magnetically for 2 h in a water bath at 60 °C to obtain a mixed solution;

[0042] ② Add 0.5g of cobalt oxide to the mixture and stir continuously with a glass rod; slowly add 0.5g of crystal violet and stir magnetically for 1 hour to form a colored mixture;

[0043] ③ Add 0.5g of ferrous ammonium sulfate hexahydrate to the colored mixture, sonicate for 2 hours, and then vacuum dry in a 60℃ oven for 2 hours until it becomes gel-like, forming a color-changing filler.

[0044] (2) Preparation of titanium dioxide modified graphene oxide anticorrosion filler;

[0045] ① Graphene oxide was prepared using a modified Hummers method, with the following steps: 2.5 g of flake graphite, 1.25 g of sodium nitrate, and 53 mL of concentrated sulfuric acid were placed in a beaker and mixed under ice-water bath conditions for 5 min. 6 mL of phosphoric acid was added, and the mixture was stirred for 10 min, maintaining the temperature below 4℃. 7.5 g of potassium permanganate was slowly added, and the mixture was stirred for 60 min. Then, the beaker was placed in a 40℃ water bath and magnetically stirred for 60 min. The mixture was then heated to 95℃ and magnetically stirred for another 60 min. Deionized water was added until the volume of the mixture increased to 400 mL. After standing for 10 min, 10 mL of hydrogen peroxide was slowly added dropwise to obtain a suspension, which was then centrifuged (5000 r / min, 5 min). The precipitate was repeatedly centrifuged and washed with deionized water and 5% hydrochloric acid solution until the washing solution was neutral. The sample was then vacuum dried at 80℃ for 6 h and sieved (400 mesh) to obtain graphene oxide powder.

[0046] ② Weigh 0.2g of nano-titanium dioxide and add it to 10mL of N,N-dimethylformamide (DMF) solution. Stir for 0.5h to obtain an N,N-dimethylformamide dispersion of nano-titanium dioxide.

[0047] ③ While adding 0.3g of graphene oxide to the N,N-dimethylformamide dispersion of nano-titanium dioxide, stir continuously with a glass rod and sonicate for 0.5h to obtain a mixed dispersion;

[0048] ④ Pour the mixed dispersion into the liner of the reactor, perform hydrothermal reaction at 280℃ for 6 hours, vacuum dry for 2 hours, ball mill for 3 hours, and wash repeatedly with deionized water to prepare the modified graphene oxide anticorrosive filler.

[0049] (3) Preparation of thermo-induced irreversible self-sensing color-changing anti-corrosion coating;

[0050] ① Add 1g of color-changing filler to 10g of epoxy resin emulsion and stir thoroughly to form a colored emulsion;

[0051] ② Slowly add 0.1g of modified graphene oxide anticorrosive filler and continue stirring to mix. The emulsion changes from light blue to dark blue, thus obtaining the anticorrosive emulsion.

[0052] ③ Add 0.1g of film-forming aid (defoamer and leveling agent in a mass ratio of 1:1) and 5g of curing agent, and ultrasonically mix to obtain a thermo-induced irreversible self-sensing color-changing anti-corrosion coating.

[0053] Example 2: A method for preparing a thermo-induced irreversible self-sensing color-changing anti-corrosion coating for thermal fault detection, comprising the following steps:

[0054] (1) Preparation of thermo-induced irreversible self-sensing color-changing filler;

[0055] ① Place 50 mL of xylene in a 100 mL beaker, add 2 g of nickel ammonium sulfate hexahydrate, and stir magnetically for 3 h in a water bath at 60 °C to obtain a mixed solution;

[0056] ② Add 0.5g of cobalt oxide to the mixture and stir continuously with a glass rod; slowly add 0.5g of crystal violet and stir magnetically for 1 hour to form a colored mixture;

[0057] ③ Add 0.5g of ferrous ammonium sulfate hexahydrate to the colored mixture, sonicate for 3 hours, and then vacuum dry in a 60℃ oven for 3 hours until it becomes gel-like, forming a color-changing filler.

[0058] (2) Preparation of titanium dioxide modified graphene oxide anticorrosion filler;

[0059] ① Graphene oxide was prepared using the modified Hummers method described in Example 1;

[0060] ② Weigh 0.2g of nano-titanium dioxide and add it to 10mL of N,N-dimethylformamide (DMF) solution. Stir for 1h to obtain N,N-dimethylformamide dispersion of nano-titanium dioxide.

[0061] ③ While adding 0.3g of graphene oxide to the N,N-dimethylformamide dispersion of nano-titanium dioxide, stir continuously with a glass rod and sonicate for 1 hour to obtain a mixed dispersion.

[0062] ④ Pour the mixed dispersion into the liner of the reactor, perform hydrothermal reaction at 280℃ for 6 hours, vacuum dry for 3 hours, ball mill for 3 hours, and wash repeatedly with deionized water to prepare the modified graphene oxide anticorrosion filler.

[0063] (3) Preparation of thermo-induced irreversible self-sensing color-changing anti-corrosion coating;

[0064] ① Add 1g of color-changing filler to 10g of epoxy resin emulsion and stir thoroughly to form a colored emulsion;

[0065] ② Slowly add 0.1g of modified graphene oxide anticorrosive filler and continue stirring to mix. The emulsion changes from light blue to dark blue, thus obtaining the anticorrosive emulsion.

[0066] ③ Add 0.1g of film-forming aid (defoamer and leveling agent in a mass ratio of 1:1) and 5g of curing agent, and ultrasonically mix to obtain a thermo-induced irreversible self-sensing color-changing anti-corrosion coating.

[0067] Example 3: A method for preparing a thermo-induced irreversible self-sensing color-changing anti-corrosion coating for thermal fault detection, comprising the following steps:

[0068] (1) Preparation of thermo-induced irreversible self-sensing color-changing filler;

[0069] ① Place 50 mL of xylene in a 100 mL beaker, add 2 g of nickel ammonium sulfate hexahydrate, and stir magnetically for 4 h in a water bath at 60 °C to obtain a mixed solution;

[0070] ② Add 0.5g of cobalt oxide to the mixture and stir continuously with a glass rod; slowly add 0.5g of crystal violet and stir magnetically for 1 hour to form a colored mixture;

[0071] ③ Add 0.5g of ferrous ammonium sulfate hexahydrate to the colored mixture, sonicate for 4 hours, and then vacuum dry in a 60℃ oven for 4 hours until it becomes gel-like, forming a color-changing filler.

[0072] (2) Preparation of titanium dioxide modified graphene oxide anticorrosion filler;

[0073] ① Graphene oxide was prepared using the modified Hummers method described in Example 1.

[0074] ② Weigh 0.2g of nano-titanium dioxide and add it to 10mL of N,N-dimethylformamide (DMF) solution. Stir for 1.5h to obtain an N,N-dimethylformamide dispersion of nano-titanium dioxide.

[0075] ③ While adding 0.3g of graphene oxide to the N,N-dimethylformamide dispersion of nano-titanium dioxide, stir continuously with a glass rod and sonicate for 1.5h to obtain a mixed dispersion;

[0076] ④ Pour the mixed dispersion into the liner of the reactor, perform hydrothermal reaction at 280℃ for 6 hours, vacuum dry for 4 hours, ball mill for 3 hours, and wash repeatedly with deionized water to prepare modified graphene oxide anticorrosive filler.

[0077] (3) Preparation of thermo-induced irreversible self-sensing color-changing anti-corrosion coating;

[0078] ① Add 1g of color-changing filler to 10g of epoxy resin emulsion and stir thoroughly to form a colored emulsion;

[0079] ② Slowly add 0.1g of modified graphene oxide anticorrosive filler and continue stirring to mix. The emulsion changes from light blue to dark blue, thus obtaining the anticorrosive emulsion.

[0080] ③ Add 0.1g of film-forming aid (defoamer and leveling agent in a mass ratio of 1:1) and 5g of curing agent, and ultrasonically mix to obtain a thermo-induced irreversible self-sensing color-changing anti-corrosion coating.

[0081] Example 4: A method for preparing a thermo-induced irreversible self-sensing color-changing anti-corrosion coating for thermal fault detection, comprising the following steps:

[0082] (1) Preparation of thermo-induced irreversible self-sensing color-changing filler;

[0083] ① Place 50 mL of xylene in a 100 mL beaker, add 2 g of nickel ammonium sulfate hexahydrate, and stir magnetically for 5 h in a water bath at 60 °C to obtain a mixed solution;

[0084] ② Add 0.5g of cobalt oxide to the mixture and stir continuously with a glass rod; slowly add 0.5g of crystal violet and stir magnetically for 1 hour to form a colored mixture;

[0085] ③ Add 0.5g of ferrous ammonium sulfate hexahydrate to the colored mixture, sonicate for 5 hours, and then vacuum dry in a 60℃ oven for 5 hours until it becomes gel-like, forming a color-changing filler.

[0086] (2) Preparation of titanium dioxide modified graphene oxide anticorrosion filler;

[0087] ① Graphene oxide was prepared using the modified Hummers method described in Example 1.

[0088] ② Weigh 0.2g of nano-titanium dioxide and add it to 10mL of N,N-dimethylformamide (DMF) solution. Stir for 2h to obtain N,N-dimethylformamide dispersion of nano-titanium dioxide;

[0089] ③ While adding 0.3g of graphene oxide to the N,N-dimethylformamide dispersion of nano-titanium dioxide, stir continuously with a glass rod and sonicate for 2 hours to obtain a mixed dispersion.

[0090] ④ Pour the mixed dispersion into the liner of the reactor, perform hydrothermal reaction at 280℃ for 6 hours, vacuum dry for 5 hours, ball mill for 3 hours, and wash repeatedly with deionized water to prepare modified graphene oxide anticorrosion filler.

[0091] (3) Preparation of thermo-induced irreversible self-sensing color-changing anti-corrosion coating;

[0092] ① Add 1g of color-changing filler to 10g of epoxy resin emulsion and stir thoroughly to form a colored emulsion;

[0093] ② Slowly add 0.1g of modified graphene oxide anticorrosive filler and continue stirring to mix. The emulsion changes from light blue to dark blue, thus obtaining the anticorrosive emulsion.

[0094] ③ Add 0.1g of film-forming aid (defoamer and leveling agent in a mass ratio of 1:1) and 5g of curing agent, and ultrasonically mix to obtain a thermo-induced irreversible self-sensing color-changing anti-corrosion coating.

[0095] Example 5: A method for preparing a thermo-induced irreversible self-sensing color-changing anti-corrosion coating for thermal fault detection, comprising the following steps:

[0096] (1) Preparation of thermo-induced irreversible self-sensing color-changing filler;

[0097] ① Place 50 mL of xylene in a 100 mL beaker, add 2 g of nickel ammonium sulfate hexahydrate, and stir magnetically for 6 h in a water bath at 60 °C to obtain a mixed solution;

[0098] ② Add 0.5g of cobalt oxide to the mixture and stir continuously with a glass rod; slowly add 0.5g of crystal violet and stir magnetically for 1 hour to form a colored mixture;

[0099] ③ Add 0.5g of ferrous ammonium sulfate hexahydrate to the colored mixture, sonicate for 6 hours, and then vacuum dry in a 60℃ oven for 6 hours until it becomes gel-like, forming a color-changing filler.

[0100] (2) Preparation of titanium dioxide modified graphene oxide anticorrosion filler;

[0101] ① Graphene oxide was prepared using the modified Hummers method described in Example 1.

[0102] ② Weigh 0.2g of nano-titanium dioxide and add it to 10mL of N,N-dimethylformamide (DMF) solution. Stir for 2.5h to obtain an N,N-dimethylformamide dispersion of nano-titanium dioxide.

[0103] ③ While adding 0.3g of graphene oxide to the N,N-dimethylformamide dispersion of nano-titanium dioxide, stir continuously with a glass rod and sonicate for 2.5h to obtain a mixed dispersion;

[0104] ④ Pour the mixed dispersion into the liner of the reactor, perform hydrothermal reaction at 280℃ for 6 hours, vacuum dry for 6 hours, ball mill for 3 hours, and wash repeatedly with deionized water to prepare the modified graphene oxide anticorrosive filler.

[0105] (3) Preparation of thermo-induced irreversible self-sensing color-changing anti-corrosion coating;

[0106] ① Add 1g of color-changing filler to 10g of epoxy resin emulsion and stir thoroughly to form a colored emulsion;

[0107] ② Slowly add 0.1g of modified graphene oxide anticorrosive filler and continue stirring to mix. The emulsion changes from light blue to dark blue, thus obtaining the anticorrosive emulsion.

[0108] ③ Add 0.1g of film-forming aid (defoamer and leveling agent in a mass ratio of 1:1) and 5g of curing agent, and ultrasonically mix to obtain a thermo-induced irreversible self-sensing color-changing anti-corrosion coating.

[0109] Example 6: A method for preparing a thermo-induced irreversible self-sensing color-changing anti-corrosion coating for thermal fault detection, comprising the following steps:

[0110] (1) Preparation of thermo-induced irreversible self-sensing color-changing filler;

[0111] ① Place 50 mL of xylene in a 100 mL beaker, add 2 g of nickel ammonium sulfate hexahydrate, and stir magnetically for 5 h in a water bath at 60 °C to obtain a mixed solution;

[0112] ② Add 0.5g of cobalt oxide to the mixture and stir continuously with a glass rod; slowly add 0.5g of crystal violet and stir magnetically for 1 hour to form a colored mixture;

[0113] ③ Add 0.5g of ferrous ammonium sulfate hexahydrate to the colored mixture, sonicate for 5 hours, and then vacuum dry in a 60℃ oven for 5 hours until it becomes gel-like, forming a color-changing filler.

[0114] (2) Preparation of titanium dioxide modified graphene oxide anticorrosion filler;

[0115] ① Graphene oxide was prepared using the modified Hummers method described in Example 1.

[0116] ② Weigh 0.2g of nano-titanium dioxide and add it to 10mL of N,N-dimethylformamide (DMF) solution. Stir for 2h to obtain N,N-dimethylformamide dispersion of nano-titanium dioxide;

[0117] ③ While adding 0.3g of graphene oxide to the N,N-dimethylformamide dispersion of nano-titanium dioxide, stir continuously with a glass rod and sonicate for 2 hours to obtain a mixed dispersion.

[0118] ④ Pour the mixed dispersion into the liner of the reactor, perform hydrothermal reaction at 280℃ for 6 hours, vacuum dry for 5 hours, ball mill for 3 hours, and wash repeatedly with deionized water to prepare modified graphene oxide anticorrosion filler.

[0119] (3) Preparation of thermo-induced irreversible self-sensing color-changing anti-corrosion coating;

[0120] ① Add 1g of color-changing filler to 10g of epoxy resin emulsion and stir thoroughly to form a colored emulsion;

[0121] ② Slowly add 0.1g of modified graphene oxide anticorrosive filler and continue stirring to mix. The emulsion changes from light blue to dark blue, thus obtaining the anticorrosive emulsion.

[0122] ③ Add 0.1g of film-forming aid (defoamer and leveling agent in a mass ratio of 1:1) and 5g of curing agent, and ultrasonically mix to obtain a thermo-induced irreversible self-sensing color-changing anti-corrosion coating.

[0123] Example 7: A method for preparing a thermo-induced irreversible self-sensing color-changing anti-corrosion coating for thermal fault detection, comprising the following steps:

[0124] (1) Preparation of thermo-induced irreversible self-sensing color-changing filler;

[0125] ① Place 50 mL of xylene in a 100 mL beaker, add 2 g of nickel ammonium sulfate hexahydrate, and stir magnetically for 5 h in a water bath at 60 °C to obtain a mixed solution;

[0126] ② Add 0.5g of cobalt oxide to the mixture and stir continuously with a glass rod; slowly add 0.5g of crystal violet and stir magnetically for 1 hour to form a colored mixture;

[0127] ③ Add 1g of ferrous ammonium sulfate hexahydrate to the colored mixture, sonicate for 5 hours, and then vacuum dry in a 60℃ oven for 5 hours until it becomes gelatinous, forming a color-changing filler.

[0128] (2) Preparation of titanium dioxide modified graphene oxide anticorrosion filler;

[0129] ① Graphene oxide was prepared using the modified Hummers method described in Example 1.

[0130] ② Weigh 0.2g of nano-titanium dioxide and add it to 10mL of N,N-dimethylformamide (DMF) solution. Stir for 2h to obtain N,N-dimethylformamide dispersion of nano-titanium dioxide;

[0131] ③ While adding 0.5g of graphene oxide to the N,N-dimethylformamide dispersion of nano-titanium dioxide, stir continuously with a glass rod and sonicate for 2 hours to obtain a mixed dispersion.

[0132] ④ Pour the mixed dispersion into the liner of the reactor, perform hydrothermal reaction at 280℃ for 6 hours, vacuum dry for 5 hours, ball mill for 3 hours, and wash repeatedly with deionized water to prepare modified graphene oxide anticorrosion filler.

[0133] (3) Preparation of thermo-induced irreversible self-sensing color-changing anti-corrosion coating;

[0134] ① Add 1g of color-changing filler to 10g of epoxy resin emulsion and stir thoroughly to form a colored emulsion;

[0135] ② Slowly add 0.1g of modified graphene oxide anticorrosive filler and continue stirring to mix. The emulsion changes from light blue to dark blue, thus obtaining the anticorrosive emulsion.

[0136] ③ Add 0.1g of film-forming aid (defoamer and leveling agent in a mass ratio of 1:1) and 5g of curing agent, and ultrasonically mix to obtain a thermo-induced irreversible self-sensing color-changing anti-corrosion coating.

[0137] Example 8: A method for preparing a thermo-induced irreversible self-sensing color-changing anti-corrosion coating for thermal fault detection, comprising the following steps:

[0138] (1) Preparation of thermo-induced irreversible self-sensing color-changing filler;

[0139] ① Place 50 mL of xylene in a 100 mL beaker, add 2 g of nickel ammonium sulfate hexahydrate, and stir magnetically for 5 h in a water bath at 60 °C to obtain a mixed solution;

[0140] ② Add 0.5g of cobalt oxide to the mixture and stir continuously with a glass rod; slowly add 0.5g of crystal violet and stir magnetically for 1 hour to form a colored mixture;

[0141] ③ Add 1.25g of ferrous ammonium sulfate hexahydrate to the colored mixture, sonicate for 5 hours, and then vacuum dry in a 60℃ oven for 5 hours until it becomes gel-like, forming a color-changing filler.

[0142] (2) Preparation of titanium dioxide modified graphene oxide anticorrosion filler;

[0143] ① Graphene oxide was prepared using the modified Hummers method described in Example 1.

[0144] ② Weigh 0.2g of nano-titanium dioxide and add it to 10mL of N,N-dimethylformamide (DMF) solution. Stir for 2h to obtain N,N-dimethylformamide dispersion of nano-titanium dioxide;

[0145] ③ While adding 0.6g of graphene oxide to the N,N-dimethylformamide dispersion of nano-titanium dioxide, stir continuously with a glass rod and sonicate for 2 hours to obtain a mixed dispersion.

[0146] ④ Pour the mixed dispersion into the liner of the reactor, perform hydrothermal reaction at 280℃ for 6 hours, vacuum dry for 5 hours, ball mill for 3 hours, and wash repeatedly with deionized water to prepare modified graphene oxide anticorrosion filler.

[0147] (3) Preparation of thermo-induced irreversible self-sensing color-changing anti-corrosion coating;

[0148] ① Add 1g of color-changing filler to 10g of epoxy resin emulsion and stir thoroughly to form a colored emulsion;

[0149] ② Slowly add 0.1g of modified graphene oxide anticorrosive filler and continue stirring to mix. The emulsion changes from light blue to dark blue, thus obtaining the anticorrosive emulsion.

[0150] ③ Add 0.1g of film-forming aid (defoamer and leveling agent in a mass ratio of 1:1) and 5g of curing agent, and ultrasonically mix to obtain a thermo-induced irreversible self-sensing color-changing anti-corrosion coating.

[0151] Example 9: A method for preparing a thermo-induced irreversible self-sensing color-changing anti-corrosion coating for thermal fault detection, comprising the following steps:

[0152] (1) Preparation of thermo-induced irreversible self-sensing color-changing filler;

[0153] ① Place 50 mL of xylene in a 100 mL beaker, add 2 g of nickel ammonium sulfate hexahydrate, and stir magnetically for 5 h in a water bath at 60 °C to obtain a mixed solution;

[0154] ② Add 0.5g of cobalt oxide to the mixture and stir continuously with a glass rod; slowly add 0.5g of crystal violet and stir magnetically for 1 hour to form a colored mixture;

[0155] ③ Add 1g of ferrous ammonium sulfate hexahydrate to the colored mixture, sonicate for 5 hours, and then vacuum dry in a 60℃ oven for 5 hours until it becomes gelatinous, forming a color-changing filler.

[0156] (2) Preparation of titanium dioxide modified graphene oxide anticorrosion filler;

[0157] ① Graphene oxide was prepared using the modified Hummers method described in Example 1.

[0158] ② Weigh 0.2g of nano-titanium dioxide and add it to 10mL of N,N-dimethylformamide (DMF) solution. Stir for 2h to obtain N,N-dimethylformamide dispersion of nano-titanium dioxide;

[0159] ③ While adding 0.5g of graphene oxide to the N,N-dimethylformamide dispersion of nano-titanium dioxide, stir continuously with a glass rod and sonicate for 2 hours to obtain a mixed dispersion.

[0160] ④ Pour the mixed dispersion into the liner of the reactor, perform hydrothermal reaction at 280℃ for 6 hours, vacuum dry for 5 hours, ball mill for 3 hours, and wash repeatedly with deionized water to prepare modified graphene oxide anticorrosion filler.

[0161] (3) Preparation of thermo-induced irreversible self-sensing color-changing anti-corrosion coating;

[0162] ① Add 1g of color-changing filler to 10g of epoxy resin emulsion and stir thoroughly to form a colored emulsion;

[0163] ② Slowly add 0.1g of modified graphene oxide anticorrosive filler and continue stirring to mix. The emulsion changes from light blue to dark blue, thus obtaining the anticorrosive emulsion.

[0164] ③ Add 0.1g of film-forming aid (defoamer and leveling agent in a mass ratio of 1:1) and 5g of curing agent, and ultrasonically mix to obtain a thermo-induced irreversible self-sensing color-changing anti-corrosion coating.

[0165] Example 10: A method for preparing a thermo-induced irreversible self-sensing color-changing anti-corrosion coating for thermal fault detection, comprising the following steps:

[0166] (1) Preparation of thermo-induced irreversible self-sensing color-changing filler;

[0167] ① Place 50 mL of xylene in a 100 mL beaker, add 2 g of nickel ammonium sulfate hexahydrate, and stir magnetically for 5 h in a water bath at 60 °C to obtain a mixed solution;

[0168] ② Add 0.5g of cobalt oxide to the mixture and stir continuously with a glass rod; slowly add 0.5g of crystal violet and stir magnetically for 1 hour to form a colored mixture;

[0169] ③ Add 1g of ferrous ammonium sulfate hexahydrate to the colored mixture, sonicate for 5 hours, and then vacuum dry in a 60℃ oven for 5 hours until it becomes gelatinous, forming a color-changing filler.

[0170] (2) Preparation of titanium dioxide modified graphene oxide anticorrosion filler;

[0171] ① Graphene oxide was prepared using the modified Hummers method described in Example 1.

[0172] ② Weigh 0.2g of nano-titanium dioxide and add it to 10mL of N,N-dimethylformamide (DMF) solution. Stir for 2h to obtain N,N-dimethylformamide dispersion of nano-titanium dioxide;

[0173] ③ While adding 0.5g of graphene oxide to the N,N-dimethylformamide dispersion of nano-titanium dioxide, stir continuously with a glass rod and sonicate for 2 hours to obtain a mixed dispersion.

[0174] ④ Pour the mixed dispersion into the liner of the reactor, perform hydrothermal reaction at 280℃ for 6 hours, vacuum dry for 5 hours, ball mill for 3 hours, and wash repeatedly with deionized water to prepare modified graphene oxide anticorrosion filler.

[0175] (3) Preparation of thermo-induced irreversible self-sensing color-changing anti-corrosion coating;

[0176] ① Add 2g of color-changing filler to 10g of epoxy resin emulsion and stir thoroughly to form a colored emulsion;

[0177] ② Slowly add 0.3g of modified graphene oxide anticorrosive filler and continue stirring to mix. The emulsion changes from light blue to dark blue, thus obtaining the anticorrosive emulsion.

[0178] ③ Add 0.8g of film-forming aid (defoamer and leveling agent in a mass ratio of 1:1) and 5g of curing agent, and ultrasonically mix to obtain a thermo-induced irreversible self-sensing color-changing anti-corrosion coating.

[0179] Example 11: A method for preparing a thermo-induced irreversible self-sensing color-changing anti-corrosion coating for thermal fault detection, comprising the following steps:

[0180] (1) Preparation of thermo-induced irreversible self-sensing color-changing filler;

[0181] ① Place 50 mL of xylene in a 100 mL beaker, add 2 g of nickel ammonium sulfate hexahydrate, and stir magnetically for 5 h in a water bath at 60 °C to obtain a mixed solution;

[0182] ② Add 0.5g of cobalt oxide to the mixture and stir continuously with a glass rod; slowly add 0.5g of crystal violet and stir magnetically for 1 hour to form a colored mixture;

[0183] ③ Add 1g of ferrous ammonium sulfate hexahydrate to the colored mixture, sonicate for 5 hours, and then vacuum dry in a 60℃ oven for 5 hours until it becomes gelatinous, forming a color-changing filler.

[0184] (2) Preparation of titanium dioxide modified graphene oxide anticorrosion filler;

[0185] ① Graphene oxide was prepared using the modified Hummers method described in Example 1.

[0186] ② Weigh 0.2g of nano-titanium dioxide and add it to 10mL of N,N-dimethylformamide (DMF) solution. Stir for 2h to obtain N,N-dimethylformamide dispersion of nano-titanium dioxide;

[0187] ③ While adding 0.5g of graphene oxide to the N,N-dimethylformamide dispersion of nano-titanium dioxide, stir continuously with a glass rod and sonicate for 2 hours to obtain a mixed dispersion.

[0188] ④ Pour the mixed dispersion into the liner of the reactor, perform hydrothermal reaction at 280℃ for 6 hours, vacuum dry for 5 hours, ball mill for 3 hours, and wash repeatedly with deionized water to prepare modified graphene oxide anticorrosion filler.

[0189] (3) Preparation of thermo-induced irreversible self-sensing color-changing anti-corrosion coating;

[0190] ① Add 2.5g of color-changing filler to 10g of epoxy resin emulsion and stir thoroughly to form a colored emulsion;

[0191] ② Slowly add 0.5g of modified graphene oxide anticorrosive filler and continue stirring to mix. The emulsion changes from light blue to dark blue, thus obtaining the anticorrosive emulsion.

[0192] ③ Add 1g of film-forming aid (defoamer and leveling agent in a mass ratio of 1:1) and 5g of curing agent, and mix with ultrasound to obtain a thermo-induced irreversible self-sensing color-changing anti-corrosion coating.

[0193] The performance of the thermo-induced irreversible self-sensing color-changing anti-corrosion coatings obtained in each embodiment was tested, and the results are shown in Table 1.

[0194] Table 1

[0195]

[0196] The thermotropic, irreversible, self-sensory color-changing anti-corrosion coating of Example 10 was applied to a Q235 tinplate sheet (60mm × 100mm) and subjected to a temperature rise test. The heating process and the coating morphology before and after heating were photographed and recorded. Figure 1 and Figure 2 As shown, the coating is dark blue at room temperature (24℃) before heating. It begins to change color when heated to 258℃ and turns completely yellow at 264℃. The color change takes about 3 minutes and the color change effect is obvious.

[0197] Infrared spectroscopy and Raman spectroscopy were performed on nickel ammonium sulfate, crystal violet, ferrous ammonium sulfate, and the thermo-induced irreversible self-sensory color-changing filler of Example 10, respectively. Figure 3 As shown, in the infrared spectrum of nickel ammonium sulfate, 2048 cm⁻¹ -1 The absorption peak at this location corresponds to the stretching vibration of the Ni-S bond, while the infrared absorption peak at this position disappears, indicating that the Ni-S bond is opened and the vibration disappears. In the infrared spectra of crystal violet and the thermally induced irreversible self-sensory color-changing filler, the absorption peak at 1721 cm⁻¹ corresponds to the stretching vibration of the Ni-S bond. -1 The absorption peak at 1582 cm⁻¹ corresponds to the stretching vibration of the C=O bond. The presence of this absorption peak at this position in the thermochromic irreversible color-changing material indicates that the C=O bond is retained. -1 The absorption peak at 1286 cm⁻¹ corresponds to the stretching vibration of the C=C bond on the aromatic ring. -1 The absorption peak at 622 cm⁻¹ is due to the stretching vibration of the CO bond. -1 The absorption peak at that location may be due to the bending vibration of the CH bonds on the aromatic ring. For example... Figure 4 As shown, in Raman spectroscopy, ferrous ammonium sulfate and nickel ammonium sulfate can only be detected at 980 cm⁻¹. -1The Raman peak at 1163 cm⁻¹ corresponds to the SO bond symmetric stretching vibration. In the Raman spectra of crystal violet and thermo-induced irreversible autochromic materials, the peak at 1163 cm⁻¹ corresponds to this vibration. -1 The absorption peak at 2787 cm⁻¹ represents the vibration of the CN bond. -1 The absorption peak at [location] corresponds to the stretching vibration of the NH bond, indicating that a chemical reaction occurred during the preparation process of the thermo-induced irreversible self-sensory color-changing filler, resulting in the disappearance of SO bonds and an increase in NH groups. XRD analysis of graphene oxide and modified graphene oxide fillers showed [further details needed]. Figure 5 As shown, at 2θ = 11.6°, the typical characteristic peak with narrow peak width and high intensity corresponds to the (001) crystal plane of GO, and the absence of other shaped impurities indicates that the structure of GO is stable and complete. The peaks of the modified graphene oxide anticorrosion filler at 2θ = 25.28°, 37.80°, 48.05°, 53.89°, 55.06°, and 62.69° correspond to the (101), (004), (200), (105), (211), and (204) crystal planes in the TiO2 standard card, indicating that an effective composite grafting reaction has occurred between the two. After testing multiple physical indicators, it was found that the physical indicators of the thermotropic irreversible self-sensory color-changing anticorrosion coating were improved compared with epoxy resin.

[0198] Based on the characterization results above, it is evident that the addition of modified GO material to the epoxy resin coating enhances its corrosion resistance by creating a labyrinth effect through the two-dimensional lamellar structure of GO, which blocks corrosive media. Furthermore, the irreversible thermochromic material imparts excellent temperature indication capabilities to the epoxy resin coating. Microscopic morphology analysis of the irreversible thermochromic material reveals numerous pores after color change, with the granular components recombining to form an integrated porous structure. Combined with XRD and FTIR results, it is observed that the interplanar spacing of the material increases, exhibiting lattice expansion, and the color-changing filler integrates. This explains the appearance of numerous pores and the generation of new CH and CN peaks during the color-changing process.

[0199] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and all such changes and modifications will fall within the scope of protection of the present invention.

Claims

1. A method for preparing a thermo-induced irreversible self-sensing color-changing anti-corrosion coating for thermal fault detection, characterized in that, Includes the following steps: (1) Preparation of thermo-induced irreversible self-sensing color-changing filler; ① Add nickel ammonium sulfate hexahydrate to organic solvent A and stir until homogeneous to obtain a mixture; ②Then add coloring agent and color-developing agent to the mixture to form a colored mixture; ③ Add ferrous ammonium sulfate hexahydrate to the colored mixture, mix evenly by ultrasonication, and vacuum dry to a gel-like state to obtain the color-changing filler; (2) Add graphene oxide to the N,N-dimethylformamide dispersion of nano-titanium dioxide, and then prepare titanium dioxide modified graphene oxide anticorrosion filler by hydrothermal method. (3) Preparation of thermo-induced irreversible self-sensing color-changing anti-corrosion coating; ① Add the color-changing filler prepared in step (1) to the epoxy resin emulsion and stir thoroughly to form a colored emulsion; ② Slowly add the modified graphene oxide anticorrosive filler prepared in step (2) to the colored emulsion, and continue to stir and mix to obtain the anticorrosive emulsion; ③ Add film-forming aid and curing agent to the anti-corrosion emulsion, mix well and obtain thermo-induced irreversible self-sensing color-changing anti-corrosion coating; The colorant mentioned in step (1) ② is cobalt oxide, and the colorant is crystal violet.

2. The method for preparing a thermo-induced irreversible self-sensing color-changing anti-corrosion coating for thermal fault detection according to claim 1, characterized in that: The organic solvent A mentioned in step (1) ① is xylene.

3. The method for preparing a thermo-induced irreversible self-sensing color-changing anti-corrosion coating for thermal fault detection according to claim 2, characterized in that: In step (1) ②, the mass ratio of cobalt oxide to nickel ammonium sulfate hexahydrate is 0.5:2, and the mass ratio of crystal violet to nickel ammonium sulfate hexahydrate is 0.5:2; in step (1) ③, the mass ratio of ferrous ammonium sulfate hexahydrate to nickel ammonium sulfate hexahydrate is (1~2.5):

4.

4. The method for preparing a thermo-induced irreversible self-sensing color-changing anti-corrosion coating for thermal fault detection according to claim 1, characterized in that: The stirring time in step (1)① is 2~6 hours, the ultrasonic time in step (1)③ is 2~6 hours, and the vacuum drying time in step (1)③ is 2~6 hours.

5. The method for preparing a thermo-induced irreversible self-sensing color-changing anti-corrosion coating for thermal fault detection according to claim 1, characterized in that: The preparation of titanium dioxide-modified graphene oxide anticorrosion filler in step (2) includes the following processes: ① Graphene oxide was prepared using the Hummers method; ② Add nano-titanium dioxide to N,N-dimethylformamide, stir and disperse evenly to obtain a dispersion of nano-titanium dioxide in N,N-dimethylformamide; ③ Add graphene oxide to the N,N-dimethylformamide dispersion of nano-titanium dioxide to obtain a mixed dispersion; ④ Pour the above mixed dispersion into a reaction vessel for hydrothermal reaction, then vacuum dry, ball mill, and wash to obtain modified graphene oxide anticorrosive filler.

6. The method for preparing a thermo-induced irreversible self-sensing color-changing anti-corrosion coating for thermal fault detection according to claim 5, characterized in that: In step (2) ③, the mass ratio of graphene oxide to nano-titanium dioxide is (1.5~3):

1.

7. The method for preparing a thermo-induced irreversible self-sensing color-changing anti-corrosion coating for thermal fault detection according to claim 5, characterized in that: Step 2① describes the preparation of graphene oxide using the Hummers method, which includes the following processes: Flake graphite and sodium nitrate were added to concentrated sulfuric acid according to the mass fraction. The mixture was allowed to stand and mix evenly under ice-water bath conditions. Phosphoric acid was added and stirred. Potassium permanganate was slowly added while controlling the temperature below 4 °C. The reaction was allowed to proceed for 1 hour. Then, the reaction was continued at 40 °C and 95 °C for 1 hour each. Deionized water was added and the mixture was allowed to stand. Hydrogen peroxide was slowly added dropwise to obtain a suspension. After the reaction was completed, the mixture was centrifuged, and the precipitate was washed until neutral. The precipitate was then vacuum dried, ground, and sieved to obtain graphene oxide powder.

8. The method for preparing a thermo-induced irreversible self-sensing color-changing anti-corrosion coating for thermal fault detection according to claim 1, characterized in that: In step (3), the mass ratio of color-changing filler to epoxy resin is 1~2.5:10, and the mass ratio of modified graphene oxide to epoxy resin is 0.1~0.5:

10.

9. The method for preparing a thermo-induced irreversible self-sensing color-changing anti-corrosion coating for thermal fault detection according to claim 1, characterized in that: The film-forming aids in step (3) ③ include defoamers and leveling agents, and the mass ratio of the film-forming aids to epoxy resin is 0.1~1:

10.

10. A thermo-induced irreversible self-sensing color-changing anti-corrosion coating for thermal fault detection, characterized in that: The thermo-induced irreversible self-sensing color-changing anti-corrosion coating is prepared by the preparation method described in any one of claims 1 to 9.

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