Metal zinc sheet with zinc molybdate anticorrosive coating and preparation method thereof

Abstract

The invention provides a preparation method of a metal zinc sheet with a zinc molybdate anticorrosive coating, which comprises the following steps: S1, dissolving a zinc salt and a molybdenum salt in a deionized water solution to obtain a mixed solution; s2, a metal zinc sheet is placed in the mixed solution at the room temperature, and after standing reaction, the metal zinc sheet with a zinc molybdate anti-corrosion film is obtained; and S3, the metal zinc sheet with the zinc molybdate anti-corrosion film is washed and dried, and the metal zinc sheet with the zinc molybdate anti-corrosion coating is obtained. And when the molar ratio of zinc nitrate to sodium molybdate is 1: 1 and the standing reaction time is 3h, the prepared metal zinc sheet with the zinc molybdate anticorrosive coating has the best protection effect in a 2mol / L ZnSO4 solution, the corrosion current density is only 2.66 * 10 <-6 > A / cm < 2 >, and the protection efficiency is 99.9%. The zinc molybdate anti-corrosion coating prepared by adopting a normal-temperature co-precipitation method has good adhesive force to the substrate, and the corrosion resistance of the metal zinc substrate is greatly improved.

Description

Technical Field

[0001] The invention belongs to the technical field of metal material corrosion and protection, and specifically relates to a metal zinc sheet with a zinc molybdate anti-corrosion coating and a preparation method thereof. Background Art

[0002] As a promising energy storage system, aqueous zinc-ion batteries (ZIBs) will become a strong candidate for large-scale energy storage system deployment due to their high safety, low cost and environmental friendliness, as well as high theoretical specific capacity and appropriate redox potential. In terms of parasitic reactions, the highly chemically active zinc anode reacts with the aqueous electrolyte, resulting in the formation of Zn4SO4(OH)6·nH2O byproducts and the release of H2. The slow corrosion reaction of the zinc anode can lead to rapid capacity decay and cycle instability of the battery. Among them, interface modification is one of the most effective strategies to regulate the chemical reaction at the metal / electrolyte solution interface. The corrosion of metallic zinc in ZnSO4 solution can be greatly reduced by simple in-situ coating of the metal surface.

[0003] Mixed transition metal oxides have attracted more and more attention from researchers due to their high theoretical capacity and environmental friendliness. Among them, molybdate treatment has many advantages, including its environmental acceptability and thermal and chemical stability. Due to its strong oxidizing properties, its reduction product is stable and can form a passivation film and provide multi-metal protection for the substrate. It is worth exploring how to treat metallic zinc with molybdate to obtain more effective protection. Summary of the invention

[0004] The present invention is made to solve the above problems, and aims to provide a metal zinc sheet with a zinc molybdate anticorrosion coating and a preparation method thereof.

[0005] The present invention provides a method for preparing a metal zinc sheet having a zinc molybdate anti-corrosion coating, which has the following characteristics and comprises the following steps:

[0006] Step S1, dissolving zinc salt and molybdenum salt in a deionized water solution to obtain a mixed solution;

[0007] Step S2, placing the metal zinc sheet in the mixed solution at room temperature, and allowing it to stand for reaction to obtain a metal zinc sheet having a zinc molybdate anticorrosive film;

[0008] Step S3, washing and drying the metal zinc sheet with the zinc molybdate anti-corrosion film to obtain a metal zinc sheet with the zinc molybdate anti-corrosion coating.

[0009] Wherein, in step S1, the molar ratio of zinc salt to molybdenum salt is 1:1-1:0.1, and the obtained mixed solution is a zinc salt and molybdenum salt solution with a concentration of 0.1 mol / L to 0.3 mol / L.

[0010] The method for preparing the metal zinc sheet with zinc molybdate anticorrosive coating provided by the present invention may also have the following characteristics: wherein the zinc salt is zinc nitrate, zinc chloride or zinc acetate.

[0011] In the method for preparing the metal zinc sheet with zinc molybdate anti-corrosion coating provided by the present invention, it can also have the following characteristics: wherein the molybdenum salt is ammonium molybdate, sodium molybdate, molybdenum chloride or molybdenum nitrate.

[0012] The method for preparing the metal zinc sheet with zinc molybdate anti-corrosion coating provided by the present invention may also have the following characteristics: wherein, in step S2, the duration of the static reaction is 1 h to 5 h.

[0013] The method for preparing the metal zinc sheet with zinc molybdate anti-corrosion coating provided by the present invention may also have the following characteristics: wherein, in step S3, during rinsing and drying, the metal zinc sheet with zinc molybdate anti-corrosion film is rinsed with deionized water and then dried in an oven at 60°C.

[0014] The present invention also provides a metal zinc sheet with a zinc molybdate anti-corrosion coating, which has the following characteristics: the metal zinc sheet is prepared by the above-mentioned method for preparing the metal zinc sheet with a zinc molybdate anti-corrosion coating.

[0015] Functions and Effects of the Invention

[0016] According to the preparation method of the metal zinc sheet with zinc molybdate anticorrosion coating involved in the present invention, the zinc molybdate coating is prepared on the surface of the metal zinc sheet by a simple room temperature immersion coprecipitation method, which has good adhesion to the substrate and greatly improves the anticorrosion performance of the metal zinc sheet, and can overcome the corrosion problem caused by the contact between the zinc negative electrode and the electrolyte in the aqueous zinc ion battery and the influence of the coating material and inactive material added to the zinc anode by the squeeze casting technology on the battery performance. In addition, the preparation method of the present invention is simple, environmentally friendly, meets the needs of the concept of sustainable development, and provides strong support for the industrial application of zinc molybdate anticorrosion coatings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a polarization curve diagram of a blank metal zinc sheet in an embodiment of the present invention and a metal zinc sheet with a zinc molybdate anticorrosion coating prepared under different static reaction times in a 2 mol / L ZnSO4 solution;

[0018] Figure 2 It is an XRD scan of the zinc molybdate anticorrosion coating prepared when the molar ratio of zinc salt to molybdenum salt is 1:1 and the static reaction time is 3 hours in the embodiment of the present invention;

[0019] Figure 3This is a SEM image of the zinc molybdate anti-corrosion coating prepared when the molar ratio of zinc salt to molybdenum salt is 1:1 and the static reaction time is 3 hours in an embodiment of the present invention. DETAILED DESCRIPTION

[0020] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the following examples and drawings specifically describe the metal zinc sheet with zinc molybdate anti-corrosion coating and the preparation method thereof.

[0021] <Example>

[0022] A metal zinc sheet with a zinc molybdate anti-corrosion coating according to this embodiment comprises the following steps:

[0023] Step S1, dissolving zinc salt and molybdenum salt in a deionized water solution to obtain a mixed solution, the specific process is as follows:

[0024] According to the molar ratio of zinc salt to molybdenum salt of 1:1, 0.594g zinc nitrate hexahydrate and 0.484g sodium molybdate dihydrate solid were weighed and dissolved in 10ml of deionized water to obtain a mixed solution. In this embodiment, the mixed solution is a zinc nitrate and sodium molybdate solution with a concentration of 0.2mol / L.

[0025] Step S2, placing the metal zinc sheet in the mixed solution at room temperature, and allowing it to stand for reaction to obtain a metal zinc sheet with a zinc molybdate anticorrosive film.

[0026] In this embodiment, the metal zinc sheet is also polished, as follows:

[0027] The metal zinc sheet was polished on different grades of silicon carbide sandpaper, such as 80#, 400#, 600#, 1000#, 1500# and 2000#, respectively, and then cleaned with acetone and deionized water for 5 minutes, respectively, and finally dried in air.

[0028] Step S3, washing and drying the metal zinc sheet with the zinc molybdate anti-corrosion film to obtain the metal zinc sheet with the zinc molybdate anti-corrosion coating, the specific process is as follows:

[0029] The metal zinc sheet with the zinc molybdate anti-corrosion film was rinsed with deionized water, and then dried in an oven at 60° C. to obtain the metal zinc sheet with the zinc molybdate anti-corrosion coating.

[0030] In this embodiment, the prepared metal zinc sheet with zinc molybdate anti-corrosion coating is also tested, and the test method is as follows:

[0031] A classic three-electrode system was used, with the working electrode being a metal zinc sheet, the auxiliary electrode being a platinum electrode, and the reference electrode being a saturated calomel electrode (SCE). The potentials shown in this embodiment were all relative to the saturated calomel electrode.

[0032] The equipment used for the determination of AC impedance and polarization curves is Shanghai Chenhua electrochemical workstation CHI660e, the AC impedance measurement frequency range is 100.00kHz~10.00mHz, the AC excitation signal is 5mV, and the scanning rate of the polarization curve is 5mV / s.

[0033] In this embodiment, the metal zinc sheets used in the test include blank zinc sheets without coating and metal zinc sheets with zinc molybdate anti-corrosion coatings prepared at standing reaction times of 1 h, 2 h, 3 h, and 5 h, respectively.

[0034] Figure 1 It is a polarization curve diagram of a blank metal zinc sheet in an embodiment of the present invention and a metal zinc sheet with a zinc molybdate anti-corrosion coating prepared under different static reaction times in a 2 mol / L ZnSO4 solution.

[0035] like Figure 1 As shown in the figure, curves (1), (2), (3), (4), and (5) are polarization curves of blank zinc sheets and metal zinc sheets with zinc molybdate anticorrosive coatings prepared at standing reaction times of 1 h, 2 h, 3 h, and 5 h in 2 mol / L ZnSO4 solution, respectively. Table 1 is obtained based on the curve data as follows:

[0036] Table 1 Electrochemical parameters and protection efficiency of each sample in 2 mol / L ZnSO4 solution

[0037]

[0038] According to Table 1, the corrosion current density of the bare Zn sample without coating is 2.75×10 -3 A / cm 2 When the metal zinc sheet with zinc molybdate anticorrosion coating was prepared by coprecipitation reaction at room temperature for 3 h, the corrosion current density was reduced to 2.66×10 -6 A / cm 2 , the protection efficiency is 99.90%.

[0039] The results show that the reaction time has a certain degree of influence on the corrosion resistance of the zinc molybdate coating formed on the surface of the metal zinc sheet. When the reaction time is 3h, the corresponding zinc molybdate coating has the best protective effect on the Zn substrate in the solution.

[0040] Figure 2 This is an XRD scan of the zinc molybdate anti-corrosion coating prepared when the molar ratio of zinc salt to molybdenum salt is 1:1 and the static reaction time is 3 hours in an embodiment of the present invention.

[0041] like Figure 2As shown, compared with the JADE standard card of zinc molybdate, it is proved that the zinc molybdate coating is successfully synthesized.

[0042] Figure 3 This is a SEM image of the zinc molybdate anti-corrosion coating prepared when the molar ratio of zinc salt to molybdenum salt is 1:1 and the static reaction time is 3 hours in an embodiment of the present invention. Figure 3 (a) and (b) are SEM images of zinc molybdate anti-corrosion coating at different magnifications.

[0043] like Figure 3 As shown in the figure, the sample surface presents densely stacked wedges, and each wedge is connected to each other. The results show that the in-situ synthesized zinc molybdate coating can effectively close the pores and thus prevent the corrosive ions from corroding the substrate.

[0044] Functions and Effects of the Embodiments

[0045] According to the preparation method of the metal zinc sheet with zinc molybdate anticorrosion coating involved in this embodiment, the zinc molybdate coating is prepared on the surface of the metal zinc sheet by a simple room temperature immersion coprecipitation method, which has good adhesion to the substrate and greatly improves the anticorrosion performance of the metal zinc sheet, and can overcome the corrosion problem caused by the contact between the zinc negative electrode and the electrolyte in the aqueous zinc ion battery and the influence of the coating material and inactive material added to the zinc anode by the squeeze casting technology on the battery performance. In addition, the preparation method of the present invention is simple, environmentally friendly, meets the needs of the concept of sustainable development, and provides strong support for the industrial application of zinc molybdate anticorrosion coatings.

[0046] Moreover, when the molar ratio of zinc nitrate to sodium molybdate is 1:1 and the static reaction time is 3 h, the prepared metal zinc sheet with zinc molybdate anticorrosion coating has the best protection effect in 2 mol / L ZnSO4 solution, and the corrosion current density is only 2.66×10 -6 A / cm 2 , the protection efficiency is 99.9%.

[0047] The above-mentioned embodiments are preferred examples of the present invention and are not intended to limit the protection scope of the present invention.

Claims

1. A method for preparing a metal zinc sheet having a zinc molybdate anti-corrosion coating, characterized in that: The following steps are involved: Step S1, dissolving zinc salt and molybdenum salt in a deionized water solution to obtain a mixed solution; Step S2, placing the metal zinc sheet in the mixed solution at room temperature, and allowing it to stand for reaction to obtain a metal zinc sheet having a zinc molybdate anticorrosive film; Step S3, washing and drying the metal zinc sheet with the zinc molybdate anti-corrosion film to obtain a metal zinc sheet with the zinc molybdate anti-corrosion coating. Wherein, in step S1, the molar ratio of the zinc salt to the molybdenum salt is 1:1-1:0.

1.

2. The method for preparing a metal zinc sheet having a zinc molybdate anticorrosion coating according to claim 1, characterized in that: in, The zinc salt is zinc nitrate, zinc chloride or zinc acetate.

3. The method for preparing a metal zinc sheet having a zinc molybdate anticorrosion coating according to claim 1, characterized in that: in, The molybdenum salt is ammonium molybdate, sodium molybdate, molybdenum chloride or molybdenum nitrate.

4. The method for preparing a metal zinc sheet having a zinc molybdate anticorrosion coating according to claim 1, characterized in that: in, In step S2, the reaction is allowed to stand for 1 h to 5 h.

5. The method for preparing a metal zinc sheet having a zinc molybdate anticorrosion coating according to claim 1, characterized in that: in, In step S3, during the rinsing and drying, the metal zinc sheet having the zinc molybdate anticorrosive film is rinsed with deionized water and then dried in an oven at 60°C.

6. A metal zinc sheet with a zinc molybdate anti-corrosion coating, characterized in that: The zinc sheet is prepared by the method for preparing a metal zinc sheet having a zinc molybdate anti-corrosion coating as described in any one of claims 1 to 5.

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