Fluxing agent suitable for methanesulfonic acid system tin plating solution and manufacturing method of electroplated tin plate

Abstract

The invention discloses a fluxing agent suitable for a methanesulfonic acid system tin plating solution. The fluxing agent contains benzene hydroxyl-containing sulfonic acid, sulfosalicylic acid and an alkyl glycoside surfactant. The invention further discloses a manufacturing method of the electroplated tin plate. The manufacturing method comprises the steps that the cold-rolled strip steel base plate is pretreated; the pretreated cold-rolled strip steel substrate is subjected to electrotinning through a methanesulfonic acid system tinning solution; the fluxing agent suitable for the methanesulfonic acid system tin plating solution is adopted for fluxing a substrate subjected to electrotinning; and softening and melting the tin-plated plate. According to the fluxing agent, the leveling effect of molten tin can be improved to fill plating layer pores, so that a tin layer is flatly and uniformly laid on an intermetallic compound (a tin-iron alloy layer), grain refinement is facilitated, and the corrosion resistance of a low-tin-content tin plate is improved.

Description

Technical Field

[0001] This invention relates to a method for manufacturing a flux and a steel plate, and more particularly to a method for manufacturing a flux for tin plating solution and an electroplated tin plate. Background Technology

[0002] Tin-plated steel sheets are products with complex production technology, long manufacturing processes, and high product quality requirements. Their main principle is the use of Sn in the tin plating solution. 2+ Under the influence of an electric field, the metal is adsorbed onto a substrate that serves as the cathode, where it is reduced, crystallized, and forms a metallic tin layer. Tin-plated sheet steel is widely used in food cans, packaging materials, beverage cans, and other fields due to its corrosion resistance and good weldability.

[0003] Traditional tin plating solutions use systems such as sulfuric acid, fluoroboric acid, halogenated agents, and phenol sulfonic acid (PSA). In recent years, with the increasing environmental protection requirements, tin plating solutions have gradually shifted from phenol sulfonic acid (PSA) plating solutions to environmentally friendly methanesulfonate (MSA) systems.

[0004] However, in actual production, compared with the PSA plating solution system, the MSA plating solution has no fluxing effect. A fluxing process needs to be added before soft melting to prevent uneven distribution of the surface alloy layer and coarse grains, thereby reducing the corrosion resistance of the tinplate. Summary of the Invention

[0005] One of the objectives of this invention is to provide a flux suitable for tin plating solutions in a methanesulfonic acid system. This flux can increase the leveling effect of molten tin to fill the pores of the plating layer, so that the tin layer is evenly and smoothly spread on the intermetallic compound (tin-iron alloy layer), which helps to refine the grains and improve the corrosion resistance of tin-plated plates with low tin content.

[0006] To achieve the above objectives, the present invention proposes a flux suitable for tin plating solutions in a methanesulfonic acid system, which contains phenyl hydroxy sulfonic acid, sulfosalicylic acid and alkyl glycoside (APG) surfactants.

[0007] Furthermore, in the flux suitable for tin plating solutions in a methanesulfonic acid system as described in this invention, its effective components consist of the following: phenyl hydroxyl sulfonic acid; sulfosalicylic acid; and alkyl glycoside surfactants.

[0008] In the flux for tin plating baths in a methanesulfonic acid system described in this invention, the phenylhydroxy sulfonic acid contains hydrophilic groups. After wetting, the wettability of the tin-plated plate surface improves, allowing for maximum contact with and penetration into the tin-plated plate surface, thus achieving the best fluxing effect. Furthermore, it exhibits antioxidant properties, controlling the formation of tin oxides. Sulfonic acid and salicylic acid can enhance the leveling effect of molten tin to fill plating pores, resulting in a smooth and uniform tin layer spread on the intermetallic compound (tin-iron alloy layer). In addition, APG-type surfactants are mainly used to control the growth orientation of the tin-iron alloy layer.

[0009] Furthermore, in the flux suitable for tin plating solutions in a methanesulfonic acid system as described in this invention, the concentration of the phenyl hydroxy sulfonic acid is 10-50 ml / L, the concentration of the sulfosalicylic acid is 5-15 ml / L, and the concentration of the alkyl glycoside surfactant is 1-5 ml / L.

[0010] Furthermore, in the flux suitable for tin plating solutions in a methanesulfonic acid system described in this invention, the phenyl hydroxy sulfonic acid is selected from at least one of: phenol sulfonic acid solution and 2-hydroxybenzene sulfonic acid.

[0011] Furthermore, in the flux suitable for tin plating solutions in a methanesulfonic acid system described in this invention, the alkyl glycoside surfactant is selected from at least one of alkyl glucosinolate solution and decyl glucosinolate solution.

[0012] Another object of the present invention is to provide a method for manufacturing an electroplated tin sheet, comprising the steps of: pretreating a cold-rolled strip steel substrate; electroplating the pretreated cold-rolled strip steel substrate with tin using a methanesulfonic acid system tin plating solution; using the above-mentioned flux suitable for the methanesulfonic acid system tin plating solution to flux the tin-plated substrate; and remelting the tin-plated sheet.

[0013] Furthermore, in the method for manufacturing tin-plated plates according to the present invention, the Sn in the methanesulfonic acid system tin plating solution... 2+ The concentration is 20-25 g / L.

[0014] Furthermore, in the method for manufacturing the tin-plated plate according to the present invention, the current for tin plating is 8-12 A / dm. 2 .

[0015] Furthermore, in the method for manufacturing the electroplated tin plate according to the present invention, the temperature of the methanesulfonic acid system tin plating solution is 35-45°C.

[0016] Furthermore, in the method for manufacturing tin-plated plates according to the present invention, the methanesulfonic acid system tin plating solution contains additives and antioxidants, wherein the concentration of the additives is 25-30 ml / L and the concentration of the antioxidants is 35-50 ml / L.

[0017] Adding a novel antioxidant during the tin plating process can effectively inhibit the formation of tin oxide, reduce the oxide content on the plating surface, improve the formation speed and quality of the passivation film, reduce tin sludge production, and ensure that the corrosion resistance of the tin-plated sheet meets the standards. This solves the problems of substandard corrosion resistance, waste of tin resources, and high costs in the actual production of tin-plated sheets.

[0018] Furthermore, in the method for manufacturing tin-plated plates according to the present invention, the additives include at least one of polyoxypropylene ether and polyoxyethylene alkyl alcohol ether; the antioxidants include at least one of resorcinol and phloroglucinol.

[0019] Furthermore, in the method for manufacturing the tin-plated plate according to the present invention, the fluxing temperature is room temperature.

[0020] Furthermore, in the method for manufacturing tin-plated sheet according to the present invention, the pretreatment includes alkaline washing of cold-rolled strip steel substrate with an alkaline solution and acid washing of cold-rolled strip steel substrate with an acidic solution.

[0021] Compared with the prior art, the flux suitable for tin plating solution in methanesulfonic acid system and the manufacturing method of tin-plating plate described in this invention have the following advantages and beneficial effects:

[0022] The flux of this invention, applicable to tin plating solutions in a methanesulfonic acid system, improves the wettability of the tin-plated sheet surface, allowing for maximum contact and penetration to the tin-plated sheet surface, thus achieving the best fluxing effect. Simultaneously, this flux enhances the leveling effect of molten tin to fill plating pores, resulting in a smooth and uniform tin layer spread on the intermetallic compound (tin-iron alloy layer). Furthermore, this flux promotes uniform grain growth, aiding in grain refinement and ultimately yielding a dense and fine plating layer, improving the corrosion resistance of low-tin-content tin-plated sheets. Therefore, this flux solves the problems of uneven surface alloy layer distribution, coarse grains, and poor corrosion resistance of tin-plated sheets.

[0023] The manufacturing method of the electroplated tin plate described in this invention is highly versatile, the production process complies with environmental protection standards, the manufacturing method is simple, green, environmentally friendly, economical and practical, and has low cost, meeting market demand. Attached Figure Description

[0024] Figure 1 The SEM topography image of Example 1 is shown.

[0025] Figure 2 The SEM topography image of Example 2 is shown.

[0026] Figure 3 The SEM topography image of Example 3 is shown.

[0027] Figure 4The SEM topography image of Example 4 is shown.

[0028] Figure 5 The polarization curves of Examples 1-4 are shown schematically.

[0029] Figure 6 The XRD test spectra of Examples 1 and 2 are shown schematically.

[0030] Figure 7 The XRD test spectra of Examples 3 and 4 are shown schematically. Detailed Implementation

[0031] The following will further explain and illustrate the flux suitable for tin plating solution in methanesulfonic acid system and the manufacturing method of tin-plating plate according to the present invention with reference to specific embodiments. However, this explanation and illustration do not constitute an improper limitation on the technical solution of the present invention.

[0032] Examples 1-6

[0033] The tin-plated plates of Examples 1-6 were prepared using the following steps:

[0034] (1) Pre-treatment of cold-rolled strip steel substrate.

[0035] In some embodiments, for example, a chemical degreasing method can be used first to degrease the cold-rolled strip substrate to remove residual oil stains from its surface. The alkaline washing solution for the chemical degreasing method is a 40 g / L NaOH solution, the temperature is room temperature, and the washing time is 20 min. Then, the cold-rolled strip substrate is pickled with a 28 ml / L sulfuric acid solution for 9 s to remove the oxide film from its surface.

[0036] (2) The pretreated cold-rolled strip steel substrate was electroplated with tin using a methanesulfonic acid system tin plating solution. The specific process parameters are shown in Table 1, and the specific types and concentrations of additives and antioxidants in the tin plating solution are shown in Table 2.

[0037] Table 1.

[0038]

[0039] Table 2.

[0040]

[0041]

[0042] It should be noted that although the additives used in Examples 1-6 above are either polyoxypropylene ether or polyoxyethylene alkyl alcohol ether, it is also feasible to use a combination of these two substances in other embodiments.

[0043] Similarly, although the antioxidants used in Examples 1-6 above are either resorcinol or phloroglucinol, it is also feasible to use a combination of these two substances in other embodiments.

[0044] (3) At room temperature, the flux of the present invention, which is suitable for tin plating solution in a methanesulfonic acid system, is used to flux the cold-rolled strip steel substrate after electroplating. After fluxing, the substrate is cleaned and dried to produce a tin-plated sheet. The composition and concentration of the flux in Examples 1-6 are shown in Table 3.

[0045] Table 3.

[0046]

[0047] It should be noted that although the benzene-containing hydroxyl sulfonic acid in Examples 1-6 above used either phenol sulfonic acid solution or 2-hydroxybenzene sulfonic acid as a single substance, it is also feasible to use a combination of these two substances in other embodiments.

[0048] Similarly, although the APG surfactants in Examples 1-6 above used a single product of alkyl glucoside solution and decyl glucoside solution, it is also feasible to use a combination of these two substances in other embodiments.

[0049] (4) The prepared tin-plated plate is softened to form an alloy layer, and then passivated and oiled.

[0050] The performance tests of the electroplated tin plates obtained in Examples 1-4 included SEM, polarization curves, and XRD tests. The test results are shown in the attached figures. The specific test methods are as follows:

[0051] (1) SEM: The instrument used was a Quanta 250 field emission scanning electron microscope (SEM) manufactured by FEI GmbH in the Czech Republic. The current emitted by the electron gun excites the sample surface to generate secondary electrons, which are collected and converted to reach the screen. Thus, a synchronous scanning image of the sample surface can be seen, enabling observation of the morphology of the sample surface.

[0052] (2) Polarization curves: The Tafel curve test used a three-electrode system. The reference electrode was a saturated calomel electrode, the auxiliary electrode was a graphite electrode, and the working electrode was the tin-plated plate to be tested (working area 1 cm2). The test solution was a 3.5 wt.% NaCl solution. The test scan range was -0.2 V to -0.75 V, and the scan rate was 1 mV / s.

[0053] (3) XRD testing: X-ray diffraction phase analysis is a technique that uses the diffraction effect of X-rays in crystalline materials to analyze the material structure. Different crystalline materials have their specific crystal structures, including parameters such as lattice type and interplanar spacing. The sample is excited under X-ray irradiation and produces secondary fluorescent X-rays (identifying X-rays).

[0054] Figure 1 The SEM topography image of Example 1 is shown.

[0055] Figure 2 The SEM topography image of Example 2 is shown.

[0056] Figure 3 The SEM topography image of Example 3 is shown.

[0057] Figure 4 The SEM topography image of Example 4 is shown.

[0058] Depend on Figures 1 to 4 It can be seen that the dendrite growth of the alloy layer obtained by the tin-plated plate flux in Example 1 is uniform; the dendrite distribution of the alloy layer obtained by the tin-plated plate flux in Example 2 is dense; the dendrite growth of the alloy layer obtained by the tin-plated plate flux in Example 3 is uniform; the dendrite distribution of the alloy layer obtained by the tin-plated plate flux in Example 4 is uniform and dense, the growth direction is relatively regular, the dendrites are well angular, and the dendrite size is larger than that of the alloy layer obtained under other conditions, indicating a good fluxing effect.

[0059] Figure 5 The polarization curves of Examples 1-4 are schematically shown. Among them, A is the polarization curve of Example 1, B is the polarization curve of Example 2, C is the polarization curve of Example 3, and D is the polarization curve of Example 4.

[0060] Depend on Figure 5 It can be seen that the tin-plated plates of Examples 1-4 all have better corrosion resistance than the tin-plated plates obtained without the use of flux. Among them, the tin-plated plate of Example 4 has the lowest corrosion current density and the most positive corrosion potential, so the tin-plated plate has the best corrosion resistance.

[0061] Figure 6 The XRD test spectra of Examples 1 and 2 are shown schematically. Figure 7 The XRD test curves of Examples 3 and 4 are schematically shown. Among them, A is the XRD test curve of Example 1, B is the XRD test curve of Example 2, C is the XRD test curve of Example 3, and D is the XRD test curve of Example 4.

[0062] Depend on Figure 6 and Figure 7It can be seen that Sn (101, 200, 220) and Fe (110) orientation diffraction peaks were detected on the surface of the low-tin-content tinplate before softening. After fluxing and softening, the tinplate surface phase increased to include a tin-iron alloy layer phase (FeSn2), with FeSn2 exhibiting diffraction peaks at the 200, 211, and 220 orientations. The grain orientation of Sn changed; after softening, the 101 orientation diffraction peak disappeared, and only the 200 and 220 orientation diffraction peaks were detected. With increasing flux concentration, the crystal plane orientations of each substance remained basically unchanged, but significant changes occurred in the intensity of the diffraction peaks. It is evident from the spectra that the flux concentration had almost no effect on the 220 orientation of Sn; the position and intensity of this orientation peak were almost identical under various conditions. The 200 orientation diffraction peak of Sn in the electroplated tin plates of Examples 1-4 is obvious and has a large peak intensity. At the same time, the FeSn2(211) intensity is high. Overall, the tin plated in Example 4 has the best corrosion resistance.

[0063] It should be noted that the combination of the technical features in this case is not limited to the combination methods described in the claims of this case or the combination methods described in the specific embodiments. All technical features described in this case can be freely combined or combined in any way, unless they contradict each other.

[0064] It should also be noted that the embodiments listed above are merely specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments, and similar changes or modifications made thereto are those that can be directly derived or easily conceived by those skilled in the art from the content disclosed in the present invention, and should all fall within the protection scope of the present invention.

Claims

1. A flux suitable for tin plating baths in a methanesulfonic acid system, characterized in that, It contains: phenyl hydroxyl sulfonic acid, sulfosalicylic acid and alkyl glycoside surfactants.

2. The flux as described in claim 1, characterized in that, Its active ingredients consist of the following components: Contains benzene hydroxy sulfonic acid; Sulfosalicylic acid; Alkyl glycoside surfactants.

3. The flux as described in claim 1 or 2, characterized in that, The concentration of the phenyl hydroxy sulfonic acid is 10-50 ml / L, the concentration of the sulfosalicylic acid is 5-15 ml / L, and the concentration of the alkyl glycoside surfactant is 1-5 ml / L.

4. The flux as described in claim 1 or 2, characterized in that, The phenyl hydroxyl sulfonic acid is selected from at least one of: phenol sulfonic acid solution and 2-hydroxybenzene sulfonic acid.

5. The flux as described in claim 1 or 2, characterized in that, The alkyl glycoside surfactant is selected from at least one of alkyl glucosinolate solution and decyl glucosinolate solution.

6. A method for manufacturing an electroplated tin plate, characterized in that, Including the following steps: Pretreatment of cold-rolled strip steel substrate; Tin plating was performed on the pretreated cold-rolled strip steel substrate using a methanesulfonic acid-based tin plating solution. The flux as described in any one of claims 1-5 is used to flux the tin-plated substrate. The tin-plated sheet is softened and melted.

7. The manufacturing method as described in claim 6, characterized in that, Sn in the methanesulfonic acid system tin plating solution 2+ The concentration is 20-25 g / L.

8. The manufacturing method as described in claim 6, characterized in that, The current for tin plating is 8-12 A / dm. 2 .

9. The manufacturing method as described in claim 6, characterized in that, The temperature of the tin plating solution in the methanesulfonic acid system is 35-45℃.

10. The manufacturing method as described in claim 6, characterized in that, The methanesulfonic acid system tin plating solution contains additives and antioxidants, wherein the concentration of the additives is 25-30 mL / L and the concentration of the antioxidants is 35-50 mL / L.

11. The manufacturing method as described in claim 10, characterized in that, The additives include at least one of polyoxypropylene ether and polyoxyethylene alkyl alcohol ether; the antioxidants include at least one of resorcinol and phloroglucinol.

12. The manufacturing method as described in claim 6, characterized in that, The fluxing temperature is room temperature.

13. The manufacturing method as described in claim 6, characterized in that, The pretreatment includes alkaline washing of the cold-rolled strip steel substrate with an alkaline solution and acid washing of the cold-rolled strip steel substrate with an acidic solution.

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