Method for producing corrosion-resistant conductive material and its use in automotive basecoat

Abstract

This invention belongs to the field of conductive material preparation technology, specifically relating to a method for preparing a corrosion-resistant conductive material and its application in automotive primers. The method uses rutile titanium dioxide as a base, reduces the band gap of titanium dioxide by coating it with modified alumina, then composites it with graphene using an ultrasonic method, and finally centrifuges, dries, and grinds the resulting product. In automotive primer applications, a slurry is prepared by stirring polyvinylidene fluoride and N-methylpyrrolidone in a constant-temperature water bath. The corrosion-resistant conductive material is dispersed in the slurry and stirred to obtain a slurry, which is then uniformly sprayed onto a nickel foam substrate for automotive applications using a spray gun. This invention is simple to operate, low in cost, has a long service life, can suppress electrostatic discharge hazards, prevent environmental pollution, and solves the problem of easy corrosion of the material surface while improving the conductivity of the material.

Description

Technical Field

[0001] This invention belongs to the field of conductive material preparation technology, specifically relating to a method for preparing a corrosion-resistant conductive material and its application in automotive primers. This method helps improve the conductivity of the material while solving the problem of easy corrosion of the material surface, thereby reducing the hazards of electrostatic discharge and mitigating environmental pollution caused by material corrosion. Background Technology

[0002] Conductive materials are functional materials used on non-conductive substrates to enable them to conduct current and dissipate static charge. Most commercially available materials have improved conductivity through modifications, but their performance is unstable, easily affected by temperature and humidity, and suffers from significant drawbacks such as high manufacturing costs, complex processes, susceptibility to corrosion, and insufficient environmental friendliness. As an important inorganic raw material, rutile TiO2 possesses excellent properties such as high and low temperature resistance, corrosion resistance, high strength, and low specific gravity, and is widely used in military, aerospace, marine, machinery, chemical, and seawater desalination industries. However, pure rutile TiO2 as a conductive coating not only has poor light absorption and stability but also relatively weak antibacterial properties.

[0003] Conductive fillers are the conductive carriers of composite conductive coatings. In the 1990s, countries such as the United States, Japan, and Germany developed metal oxide-based conductive fillers, mainly including antimony-doped tin oxide, zinc oxide, and antimony trioxide. Some of these products have been commercialized. However, these traditional conductive fillers not only have unstable conductivity and are easily affected by temperature and humidity, but also have significant drawbacks such as high preparation costs and insufficient environmental friendliness.

[0004] Electrical conductivity refers to a material's ability to conduct electric current, usually described by conductivity or resistivity. High conductivity means the material can effectively conduct current, which is crucial in many applications, such as electronic devices, circuit boards, and antistatic coatings. Corrosion resistance refers to a material's ability to resist erosion by corrosive environments such as chemicals, moisture, and salt water. Materials with strong corrosion resistance can maintain the stability of their performance and appearance, extend their service life, and reduce maintenance costs. Summary of the Invention

[0005] The present invention aims to overcome the shortcomings of the prior art and provide a method for preparing a corrosion-resistant conductive material that is simple to operate, low in cost, has a long service life, can suppress the hazards of electrostatic discharge, prevent environmental pollution, improve the conductivity of the material, and solve the problem of easy corrosion of the material surface.

[0006] Another objective of this invention is to provide an application of the product obtained from a method for preparing a corrosion-resistant conductive material in automotive primers.

[0007] To solve the above-mentioned technical problems, the present invention is implemented as follows:

[0008] A method for preparing a corrosion-resistant conductive material involves using rutile phase titanium dioxide as a base, coating the rutile phase titanium dioxide with modified alumina, then ultrasonically combining it with graphene, and finally centrifuging, washing, drying, and grinding to obtain the desired product.

[0009] As a preferred embodiment, the method for preparing the corrosion-resistant conductive material includes the following specific steps:

[0010] (1) Alumina, boric acid and nanodiamond were mixed and then ball-milled to obtain modified alumina powder;

[0011] (2) The product obtained in step (1) is mixed with rutile titanium dioxide and then ball-milled again to obtain modified alumina-coated titanium dioxide powder.

[0012] (3) The product obtained in step (2) is added to a hexadecyltrimethylammonium bromide solution under stirring;

[0013] (4) Add the ultrasonically dispersed graphene to the product obtained in step (3) and perform ultrasonic dispersion again.

[0014] (5) Centrifuge the product obtained in step (4), then wash it twice with anhydrous ethanol and distilled water respectively and centrifuge it again. After that, dry and grind the centrifuged product to obtain the target product.

[0015] Further, in step (1), 2g of alumina, 4g of nanodiamond and 2g of boric acid are put into a ball mill for ball milling. The ball mill speed is set to 5000 / min and the ball milling time is set to 5h.

[0016] Further, in step (2), the modified alumina powder with a mass ratio of 1:1 to 3 is mixed with rutile phase titanium dioxide and then put into a ball mill for ball milling again. The ball mill speed is set to 300 r / min and the ball milling time is set to 3 h.

[0017] Further, in step (3), 0.2g of hexadecyltrimethylammonium bromide is dissolved in 30mL of deionized water under a constant temperature water bath at 40℃, and 1g of the product obtained in step (2) is weighed and slowly added to the above hexadecyltrimethylammonium bromide solution under constant temperature stirring.

[0018] Further, in step (4), 0.06-0.07g of graphene is dissolved in 20mL of deionized water and ultrasonically dispersed for 1h to obtain a graphene suspension; the solution obtained in step (3) is slowly added dropwise to the graphene suspension, and then ultrasonically dispersed again for 1h.

[0019] Further, in step (5), the product obtained in step (4) is centrifuged, then washed twice with anhydrous ethanol and deionized water respectively, and dried in an 80°C oven for 12 hours. After grinding the dried product, the target product is obtained.

[0020] The application of the product obtained by the above-mentioned method for preparing corrosion-resistant conductive materials in automotive primers involves preparing a slurry by stirring polyvinylidene fluoride and N-methylpyrrolidone under constant temperature water bath conditions; dispersing the corrosion-resistant conductive material into the above slurry and stirring to obtain a slurry; and then uniformly spraying the slurry onto automotive substrate nickel foam using a spray gun.

[0021] Alumina, as a commonly used material, can effectively improve the stability, optical properties, catalytic activity, and weather resistance of coatings by coating titanium dioxide. Furthermore, using ultrasonic composite graphene as a conductive agent not only enhances the conductivity of the composite material but also significantly improves the corrosion resistance of the coating, thus enhancing its protective efficiency. This invention primarily uses planetary ball milling as the main experimental method, supplemented by ultrasonic composite methods to prepare the composite material. Commercially available alumina has low activity; after ball milling at appropriate speeds and times, it can be modified. This not only changes the crystal form of the alumina, transforming it into α-alumina, which is more suitable for modifying titanium dioxide, but also increases the number of active sites on its surface. The above material treatment method involves preparing the composite material using a ball mill. However, ball mill parameter settings are complex; ball milling time and speed are single factors that must be considered, and the ratio of alumina to titanium dioxide, as well as their ball milling time and speed, cannot be ignored.

[0022] This invention uses rutile titanium dioxide as a base material. The band gap of titanium dioxide is reduced by coating modified alumina, followed by ultrasonic composite with graphene. Finally, centrifugation, drying, and grinding are performed to obtain the target product. Experiments have shown that this invention not only significantly improves the conductivity of the composite material, reducing the hazards of electrostatic discharge, but also solves the problem of easy corrosion of the material surface in air, reducing the probability of environmental pollution after corrosion. This invention not only significantly improves the conductivity of the composite material, reducing the resistivity to below 0.1 Ω·cm, but also greatly improves the protective efficiency of the coating, increasing it to over 95%. Even after immersion in salt water for 10 days, the protective efficiency remains above 85%. Furthermore, the preparation method of this invention does not generate highly toxic intermediate products, providing a high-performance material for the application of composite conductive coatings.

[0023] Compared with the prior art, the present invention has the following characteristics:

[0024] 1. This invention mainly adopts the ball milling method, specifically the planetary ball mill, which can quickly and effectively achieve pulverization and mixing, making it more suitable for large-scale applications in laboratories and industrial production; the modified titanium dioxide alumina used is inexpensive and compatible with industrial production.

[0025] 2. This invention employs ultrasonic methods, which help remove surface deposits, oxides, etc., improving the cleanliness and activity of the material surface. Furthermore, it can break down and disperse particles, contributing to improved material uniformity and stability.

[0026] 3. The operation method of this invention is simple and the conductivity and corrosion resistance are excellent. It not only has the advantages of low price, simple operation and long service life, but can also be used in photovoltaic power generation brackets, petrochemical equipment and aerospace equipment and other fields. The application range of the product is relatively wide.

[0027] 4. The present invention uses ball milling to pretreat alumina, which can not only improve the surface activity and specific surface area of ​​alumina, improve particle morphology and dispersibility, but also enhance the chemical stability and improve the mechanical properties of alumina.

[0028] 5. This invention can be widely applied in fields such as electronic information, aerospace, marine engineering, automotive industry, and chemical industry. Attached Figure Description

[0029] The present invention will now be described in detail through specific embodiments. These embodiments are provided to enable a more thorough understanding of the invention and to fully convey the scope of the invention to those skilled in the art. As used throughout the specification and claims, the terms "comprising" or "including" are open-ended and are interpreted as "comprising but not limited to". The following description is a preferred embodiment for carrying out the invention; however, this description is intended to illustrate the general principles of the specification and is not intended to limit the scope of the invention. The scope of protection of the invention is determined by the appended claims. Unless otherwise specified, all reagents and materials used in the present invention are commercially available.

[0030] Figure 1 This is a SEM image of the alumina-coated titanium dioxide composite graphene material of the present invention.

[0031] Figure 2 This is a test of the sedimentation effect of the modified alumina of the present invention.

[0032] Figure 3 Tafel corrosion curve test of the alumina-coated titanium dioxide composite graphene material of this invention. Detailed Implementation

[0033] Example 1

[0034] (1) Take 2g of alumina, 2g of nanodiamond and 2g of boric acid, put them into a planetary ball mill and ball mill to obtain modified alumina; the ball milling speed is set to 500r / min and the ball milling time is set to 5h.

[0035] (2) XRD tests were performed on the ball milled product, and it was found that the alumina was not successfully modified.

[0036] Example 2

[0037] (1) Take 2g of alumina, 6g of nanodiamond and 2g of boric acid, put them into a planetary ball mill and ball mill to obtain modified alumina; the ball milling speed is set to 500r / min and the ball milling time is set to 5h.

[0038] (2) XRD tests and dispersibility analysis of the ball-milled product revealed that the alumina modification effect was not good. Figure 2 As shown, excessive diamond can actually reduce the dispersibility of modified alumina.

[0039] Example 3

[0040] (1) Take 2g of alumina, 4g of nanodiamond and 2g of boric acid, put them into a planetary ball mill and ball mill to obtain modified alumina; the ball milling speed is set to 500r / min and the ball milling time is set to 5h.

[0041] (2) XRD tests were performed on the ball milled product, and the alumina modification was found to be successful.

[0042] (3) Collect the product from step (1), take 1g of rutile phase titanium dioxide and 4g of modified alumina obtained in step (1), and put them back into the planetary ball mill. The ball milling speed is 300r / min and the ball milling time is set to 3h.

[0043] (4) Collect the product from step (3), weigh 0.2g of CTAB and add it to 30mL of deionized water, dissolve it in a water bath at 40℃, and add 1g of the product from step (3) to it while stirring to obtain solution (4).

[0044] (5) Take 0.06g of graphene, dissolve it in 20mL of deionized water and sonicate it for 1 hour to obtain a graphene suspension. Then slowly add solution (4) dropwise into the graphene suspension and sonicate the resulting solution for 1 hour.

[0045] (6) The obtained solid product was centrifuged and washed twice with anhydrous ethanol and distilled water, and then placed in an oven to dry at 80°C for 12 hours. The dried product was then ground to obtain titanium dioxide-doped alumina composite graphene composite coating.

[0046] (7) Press the product collected in step (6) into tablets and measure its resistivity using a four-probe tester. Then, make the sample into a slurry and coat it onto nickel foam. Measure its Tafel curve using an electrochemical workstation. The protective efficiency of the coating can be calculated based on the Tafel curve.

[0047] Experimental results show that the prepared Al2O3@T / G composite material has good coating state, fast electrochemical response speed, and uniform graphene composite. The resistivity of the prepared Al2O3@T / G composite material was measured to be 1.59 Ω·cm using a four-probe analyzer. Figure 1 As shown, the corrosion current of Al2O3@T / G composite material was measured to be -4.044 A / cm2 and the corrosion potential was -0.037 V using an electrochemical workstation. The calculated protection efficiency is 85.78%.

[0048] Example 4

[0049] (1) Take 2g of alumina, 4g of nanodiamond and 2g of boric acid, put them into a planetary ball mill and ball mill to obtain modified alumina; the ball milling speed is set to 5000 / min and the ball milling time is set to 5h.

[0050] (2) Collect the product from step (1), take 3g of rutile phase titanium dioxide and 4g of modified alumina obtained in step (1), and put them back into the planetary ball mill. The ball milling speed is 300r / min and the ball milling time is set to 3h.

[0051] (3) Collect the product from step (2), weigh 0.2g of CTAB and add it to 30mL of deionized water, dissolve it in a water bath at 40℃, and add 1g of the product from step (2) to it while stirring to obtain solution (3).

[0052] (4) Take 0.06g of graphene, dissolve it in 20mL of deionized water and sonicate it for 1 hour to obtain a graphene suspension. Then slowly add solution (3) dropwise into the graphene suspension and sonicate the resulting solution for 1 hour.

[0053] (5) The obtained solid product was centrifuged and washed twice with anhydrous ethanol and distilled water, and then placed in an oven to dry at 80°C for 12 hours. The dried product was then ground to obtain titanium dioxide-doped alumina composite graphene composite coating.

[0054] Table 1 Comparison of component contents in Examples 3 and 4

[0055] Example 3 Example 4 Alumina : Nanodiamond : Boric acid = 1 : 2 : 1 Alumina : Nanodiamond : Boric acid = 1 : 2 : 1 Titanium dioxide : modified aluminum oxide = 1 : 1 Titanium dioxide : modified aluminum oxide = 3 : 1 Graphene addition amount 6% Graphene addition amount 6%

[0056] (6) Press the product collected in step (5) into tablets and measure its resistivity using a four-probe tester. Then, make the sample into a slurry and coat it onto nickel foam. Measure its Tafel curve using an electrochemical workstation. The protective efficiency of the coating can be calculated based on the Tafel curve.

[0057] Table 2 Comparison of Effects of Examples 3 and 4

[0058] Example 3 Example 4 Average resistivity: 1.59 Ω·cm Average resistivity: 1.01 Ω·cm Protection efficiency: 89.8% Protection efficiency: 90.9%

[0059] Example 5

[0060] (1) Take 2g of alumina, 4g of nanodiamond and 2g of boric acid, put them into a planetary ball mill and ball mill to obtain modified alumina; the ball milling speed is set to 500r / min and the ball milling time is set to 5h.

[0061] (2) Collect the product from step (1), take 2g of rutile phase titanium dioxide and 4g of modified alumina obtained in step (1), and put them back into the planetary ball mill. The ball milling speed is 300r / min and the ball milling time is set to 3h.

[0062] (3) Collect the product from step (2), weigh 0.2g of CTAB and add it to 30mL of deionized water, dissolve it in a water bath at 40℃, and add 1g of the product from step (2) to it while stirring to obtain solution (3).

[0063] (4) Take 0.06g of graphene, dissolve it in 20mL of deionized water and sonicate it for 1 hour to obtain a graphene suspension. Then slowly add solution (3) dropwise into the graphene suspension and sonicate the resulting solution for 1 hour.

[0064] (5) The obtained solid product was centrifuged and washed twice with anhydrous ethanol and distilled water, and then placed in an oven to dry at 80°C for 12 hours. The dried product was then ground to obtain titanium dioxide-doped alumina composite graphene composite coating.

[0065] Table 3 Comparison of component contents in Examples 3-5

[0066]

[0067] (6) Press the product collected in step (5) into tablets and measure its resistivity using a four-probe tester. Then, make the sample into a slurry and coat it onto nickel foam. Measure its Tafel curve using an electrochemical workstation. The protective efficiency of the coating can be calculated based on the Tafel curve.

[0068] Table 4 Comparison of Effects of Examples 3-5

[0069]

[0070] Example 6

[0071] (1) Take 2g of alumina, 4g of nanodiamond and 2g of boric acid, put them into a planetary ball mill and ball mill to obtain modified alumina; the ball milling speed is set to 500r / min and the ball milling time is set to 5h.

[0072] (2) Collect the product from step (1), take 2g of rutile phase titanium dioxide and 4g of modified alumina obtained in step (1), and put them back into the planetary ball mill. The ball milling speed is 300r / min and the ball milling time is set to 3h.

[0073] (3) Collect the product from step (2), weigh 0.2g of CTAB and add it to 30mL of deionized water, dissolve it in a water bath at 40℃, and add 1g of the product from step (2) to it while stirring to obtain solution (3).

[0074] (4) Take 0.07g of graphene, dissolve it in 20mL of deionized water and sonicate it for 1 hour to obtain a graphene suspension. Then slowly add solution (3) dropwise into the graphene suspension and sonicate the resulting solution for 1 hour.

[0075] (5) The obtained solid product was centrifuged and washed twice with anhydrous ethanol and distilled water, and then placed in an oven to dry at 80°C for 12 hours. The dried product was then ground to obtain titanium dioxide-doped alumina composite graphene composite coating.

[0076] Table 5 Comparison of component contents in Examples 3-6

[0077]

[0078]

[0079] (6) Press the product collected in step (5) into tablets and measure its resistivity using a four-probe tester. Then, make the sample into a slurry and coat it onto nickel foam. Measure its Tafel curve using an electrochemical workstation. The protective efficiency of the coating can be calculated based on the Tafel curve.

[0080] Table 6 Comparison of Effects of Examples 3-6

[0081]

[0082] Example 7

[0083] (1) Take 2g of alumina, 4g of nanodiamond and 2g of boric acid, put them into a planetary ball mill and ball mill to obtain modified alumina; the ball milling speed is set to 500r / min and the ball milling time is set to 5h.

[0084] (2) Collect the product from step (1), take 2g of rutile phase titanium dioxide and 4g of modified alumina obtained in step (1), and put them back into the planetary ball mill. The ball milling speed is 500r / min and the ball milling time is set to 5h.

[0085] (3) Collect the product from step (2), weigh 0.2g of CTAB and add it to 30mL of deionized water, dissolve it in a water bath at 40℃, and add 1g of the product from step (2) to it while stirring to obtain solution (3).

[0086] (4) Take 0.07g of graphene, dissolve it in 20mL of deionized water and sonicate it for 1 hour to obtain a graphene suspension. Then slowly add solution (3) dropwise into the graphene suspension and sonicate the resulting solution for 1 hour.

[0087] (5) The obtained solid product was centrifuged and washed twice with anhydrous ethanol and distilled water, and then placed in an oven to dry at 80°C for 12 hours. The dried product was then ground to obtain titanium dioxide-doped alumina composite graphene composite coating.

[0088] Table 7 Comparison of component contents in Examples 3-7

[0089]

[0090] (6) The product collected in step (5) is pressed into a tablet, and its resistivity is measured using a four-probe analyzer. The sample is then made into a slurry and coated onto nickel foam, and its impedance spectrum is measured using an electrochemical workstation. Figure 3 The protective efficiency of the coating can be calculated based on the Tafel curve.

[0091] Table 8 Comparison of Effects of Examples 3-7

[0092]

[0093] Experimental results

[0094] The alumina-coated titanium dioxide composite graphene material prepared in Example 7 was examined by scanning electron microscopy, and the results are as follows: Figure 1 As shown in the figure, the prepared composite material contains graphene sheet structure and titanium dioxide particles coated with metal oxide, and the degree of metal oxide coating is relatively good.

[0095] A comparison of the electrical conductivity and corrosion resistance of the materials in Examples 3-7 revealed that Example 5 exhibited the highest electrical conductivity and corrosion resistance. Furthermore, after immersion in 3.5% wt sodium chloride for 10 days, the protective efficiency of the coating remained above 85%, indicating that the coating's corrosion resistance remained excellent even after prolonged immersion in concentrated salt water.

[0096] It is understood that the above specific description of the present invention is only for illustrating the present invention and is not limited to the technical solutions described in the embodiments of the present invention. Those skilled in the art should understand that modifications or equivalent substitutions can still be made to the present invention to achieve the same technical effect; as long as the use needs are met, they are all within the protection scope of the present invention.

Claims

1. The application of the product obtained from the preparation method of corrosion-resistant conductive material in automotive primer, characterized in that, Its preparation method includes the following steps: (1) 2g of alumina, 4g of nano diamond and 2g of boric acid were put into a ball mill and ball milled. The ball mill speed was set to 500r / min and the ball milling time was set to 3-5h to obtain modified alumina powder. (2) After mixing the modified alumina powder with a mass ratio of 1:1 to 3 with rutile phase titanium dioxide, the mixture is put into a ball mill for ball milling again. The ball mill speed is set to 300 r / min and the ball milling time is set to 3 h to obtain the modified alumina-coated titanium dioxide powder. (3) Dissolve 0.2g of hexadecyltrimethylammonium bromide in 30mL of deionized water at a constant temperature of 40℃, weigh 1g of the product obtained in step (2), and slowly add it to the above hexadecyltrimethylammonium bromide solution under constant temperature stirring. (4) Dissolve 0.06-0.07g of graphene in 20mL of deionized water and sonicate for 1h to obtain a graphene suspension; slowly add the solution obtained in step (3) to the graphene suspension, and then sonicate again for 1h. (5) The product obtained in step (4) is centrifuged, then washed twice with anhydrous ethanol and deionized water respectively, and dried in an 80°C oven for 12 hours. The dried product is then ground to obtain the corrosion-resistant conductive material. A slurry is prepared by stirring polyvinylidene fluoride and N-methylpyrrolidone under constant temperature water bath conditions; the corrosion-resistant conductive material is dispersed into the slurry and stirred to obtain a slurry, which is then uniformly sprayed onto automotive substrate nickel foam using a spray gun.

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