CN103882484B - High-speed tin plating plating solution - Google Patents

Abstract

The invention discloses a plating solution for high-speed tin plating. The plating solution comprises the following components: 5-100g/L tin methanesulfonate, 10-100mL/L methanesulfonic acid, 0.1-20ml/L sulfuric acid, 0.1 -200mg/L defoamer, 0.1-50g/L fine crystal agent, 0.01-20g/L walking agent, 0.1-40g/L antioxidant. The plating solution of the present invention has excellent dispersion and deep plating ability, can meet various technical requirements of a high-speed tin plating production line, and can further reduce the amount of tin plating (≈0.7g/m ² ) to save resources. In addition, iron ions and chlorine in the plating solution The highest ion tolerance limits can reach 20g/L and 1000ppm respectively. The plating solution obtained by the invention is more stable than the plating solution without crystal finer agent added, and a good plating layer can still be obtained after the plating solution is used and placed for several weeks.

Description

Plating solution for high-speed tin plating

technical field

The invention belongs to the technical field of electrochemical deposition of metals and alloys, and relates to a plating solution for high-speed electroplating tin.

Background technique

High-speed electroplating tin is widely used in plate, wire and electronic electroplating. As far as electroplated tin sheet steel (commonly known as tinplate) is concerned, it is a functional material with high strength, good weldability, corrosion resistance and non-toxicity. It has been used as the main packaging material in the food industry for a long time, and is widely used in medicine, light industry, automobile and other industries. It is one of the most popular steel products.

The current electroplating tin process mostly adopts phenol sulfonic acid (PSA)-based florostane electroplating process, the electroplating line of this process accounts for 65.7% of the world's electroplating tin line, but PSA contains very toxic phenolic compounds, and the produced Waste liquid treatment costs are also relatively high. The limiting current density of this plating solution is low, so that the actual operating speed of domestic units is about 175m/min (the design line speed of the unit is generally ~600m/min), and there is still a lot of room for improvement in production efficiency. High-speed electroplating tin has high requirements on the performance of additives and plating solutions. The material to be plated must overcome the effects of parallel electric fields, gas fields, temperature fields, flow fields, and concentration fields to obtain high-quality coatings within 10s. In addition, a large part of domestic tinning units use tin blocks as soluble anodes, which need to be shut down regularly to replace the anodes. The production efficiency is low, the output of tin sludge is large, and the labor intensity of workers is high; insoluble anodes such as iridium dioxide and platinum plating are future applications. trend. During the production process, a large amount of active oxygen is precipitated from the insoluble anode, and some tin plating additives are easily aged. Therefore, the additives for high-speed tin plating and their baths are particularly urgent.

CN101922026A discloses a methanesulfonic acid-based matt pure tin electroplating additive and its plating solution. The additive contains heterocyclic compounds and amine compounds that are unfriendly to the environment. In addition, the plating solution also contains 100-150g/L of Organic solvents, organic solvents evaporate rapidly in high-speed motion and strong convection, the amount of tin sludge is not well controlled, and the plating solution is easily invalidated, which increases production costs and pollutes the environment of the production workshop. CN1570219 discloses an electroplating composition and an electroplating method. The composition contains thiourea and amine compounds, which are decomposed by heat to release oxides of nitrogen and sulfur, which is not conducive to the health of operators. CN1733977A discloses a tin-plating additive and a preparation method thereof. The additive contains polyoxyethylene aniline ether, naphthalene sulfonic acid and other environmentally unfriendly chemical substances.

US7517443B2 discloses a kind of electroplating tin bath, main component is the additive of tin sulfamic acid, sulfuric acid and N-containing ethylene oxide and propylene oxide block copolymer; Considering the hydrolysis behavior of sulfamic acid and stannous ion Stable strong acid conditions required for high-speed tin plating need further verification. USRE39476E discloses a tin electroplating solution composition, which contains polyalkylene oxide homopolymer and ethylene oxide and propylene oxide copolymer components, and the plating solution needs to be optimized in terms of foaming and defoaming capabilities; at the same time, the patent The medium antioxidant is only one or more of catechol, resorcinol and hydroquinone, which cannot effectively inhibit the black ash brought by the reflow process to tin-plated products.

Contents of the invention

The main purpose of the present invention is to provide a plating solution that can be used for high-speed electroplating tin, which is mainly used to improve the performance of the plating solution, improve the quality of the coating, and meet the requirements of high-speed electroplating; Consumption, reduce production costs, and at the same time realize the localization of high-speed tin plating additives and their plating solutions.

The purpose of the present invention is achieved through the following technical solutions:

A plating solution for high-speed tin plating, comprising the following components: tin methanesulfonate 5-100g/L, methanesulfonic acid 10-100mL/L, sulfuric acid 0.1-20ml/L, additives: 0.1-200mg/L Defoamer, 10-50g/L fine crystal agent, 0.01-20g/L moving agent, 0.1-40g/L antioxidant.

In the present invention, the defoamer is a type of compound of polyoxyethylene oxypropylene glycerol with a molecular weight of 500-15000.

In the present invention, the fine crystal agent is a mixture of one or more of formaldehyde, ethylene oxide and propylene oxide copolymer. It is preferably a mixture of one, two or three random copolymers of formaldehyde, ethylene oxide and propylene oxide block copolymers and random copolymers.

In the present invention, the said block polymer of crystal finer agent is MO _x -EO _y , PO _x -EO _y , MO _x -EO _y -MO _z , EO _x -MO _y -EO _z , MO _x -EO _y -PO _z , EO _x -MO _y -PO _z , EO _x -PO _y -MO _z , PO _x -EO _y -PO _z , EO _x -PO _y -EO _z and random copolymers are MO _m EO _n PO _t . Among them, MO is methoxy, EO is ethoxy, PO is propoxy; x, y, z are the degree of polymerization of MO, EO, PO of block copolymer, x, y, z, m, n and The range of t is 1-60.

In the present invention, the mass content of the crystal finer agent EO is 5-90%, the polymer molecular weight is between 2000-10000, the density is 1.10±0.10g/cm ³ , and the cloud point is 55-95°C.

In the present invention, the displacement agent is a kind of alkyl alcohol polyoxyethylene ether, which can increase the limiting current density value of the plating solution. Its structural formula is RO-(CH ₂ CH ₂ O)nH, R is a saturated C7~13 branched hydrocarbon group, and n is within 60-280.

In the present invention, the antioxidant is any two of hydroquinone, catechol, resorcinol, ascorbic acid, malic acid, citric acid, and tartaric acid, mixed in a molar ratio of 1:0.1-5 .

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

1. The additives for high-speed tin plating provided by the present invention do not contain anion, cation, and amphoteric surfactants, polyoxymethylene, polyethylene oxide, and polypropylene oxide homopolymers, aldehydes, heterocyclic compounds, and amines compounds, polyaminocarboxylic acids, sulfur amino acids, and any organic solvents.

2. The water used in the present invention to configure the concentrated additive solution and the plating solution is deionized water with a conductivity of <20 μS/cm; the obtained coating is a gray-white matte coating.

3. The working temperature range of the plating solution composed of the additives of the present invention is 10-70°C; under high-speed conditions, the limiting current density of the plating solution containing the additives of the present invention can reach 60-120A/dm ² .

4. The plating solution composed of additives of the present invention has excellent dispersion and deep plating ability, can meet various technical requirements of high-speed tin plating production line, and can further reduce the amount of tin plating (≈0.7g/m ² ) to save resources. In addition, the plating solution The tolerance limits of iron ions and chloride ions can reach up to 20g/L and 1000ppm respectively.

5. The plating solution composed of additives of the present invention can obtain a finely crystallized and evenly covered coating under the condition of a line speed of 0-800m/min.

6. The additive of the present invention and the plating bath composed thereof do not contain biodegradable substances and environmentally unfriendly chemicals, and the sewage treatment is simple and meets the requirements of environmental protection. It is worthy of popularization and use in the high-speed tin plating industry.

7. The plating solution obtained in the present invention is more stable than the plating solution without crystal finer agent added, and a good plating layer can still be obtained after the plating solution is used and placed for several weeks.

Description of drawings

Fig. 1 is the photograph of the Hall cell sample of embodiment 1, and experimental condition is 45 ℃, 2A, 2min, without convective stirring;

Fig. 2 is the photograph of the Hall cell sample of embodiment 2, the experimental condition is 45 ℃, 2A, 2min, without convective stirring;

Fig. 3 is the photograph of the Hall cell sample of embodiment 3, the experimental condition is 45 ℃, 2A, 2min, without convective stirring;

Fig. 4 is the SEM photograph of the 0.7g/m ² tinplate that embodiment 1 obtains under 15.0A/dm ² different current density conditions;

Figure 5 is the local energy spectrum analysis of the SEM photo of the 0.7g/ ^m2 coated tinplate obtained in Example 1 at 15.0A/dm2 (spectrum ² );

Figure 6 is the local energy spectrum analysis of the SEM photo of the 0.7g/ ^m2 coated tinplate obtained at 15.0A/dm2 in Example ¹ (spectrum 3);

Fig. 7 is the SEM photograph of the 1.1g/m ² tinplate obtained under the condition of 6.75A/dm ² in Example 1;

Fig. 8 is the SEM photograph of the 1.1g/m ² tinplate obtained under the condition of 15.0A/dm ² in Example 1;

Fig. 9 is the SEM photograph of the 1.1g/m ² tinplate obtained under the condition of 24.75A/dm ² in Example 1;

Figure 10 is the local energy spectrum analysis of the SEM photo of the 1.1g/ ^m2 coated tinplate obtained at 15.0A/dm2 in Example ¹ (spectrum 3);

Figure 11 is the local energy spectrum analysis of the SEM photo of the 1.1g/ ^m2 coated tinplate obtained at 15.0A/dm2 in Example ¹ (spectrum 4);

Fig. 12 is a 6000 times SEM photo of the 1.1g/m ² tin-plated plate obtained under the condition of 15.0A/dm ² in Example 1;

Figure 13 is a 6000 times SEM photo of the 1.1g/m ² tin-plated plate obtained under the condition of 15.0A/dm ² in Example 2;

Fig. 14 is a 6000 times SEM photograph of a 1.1 g/m ² tinned plate obtained in Example 3 under the condition of 15.0 A/dm ² .

detailed description

The technical solution of the present invention will be further described below in conjunction with the examples, and the composition of the plating solution and the process conditions can be adjusted according to product requirements. Any modification or equivalent replacement of the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention shall be included in the protection scope of the present invention.

Example 1

Tin methanesulfonate 45g/L

Methanesulfonic acid 45ml/L

Sulfuric acid 10ml/L

Polyoxyethylene oxypropylene glycerin (molecular weight 4000) 0.1mg/L

MO ₁₅ -EO ₂₁ -PO ₃₀ 10g/L

Octyl alcohol polyoxyethylene ether (molecular weight 8000) 0.6g/L

Hydroquinone + malic acid 15g/L

Temperature 45°C

Example 2

Tin methanesulfonate 15g/L

Methanesulfonic acid 30ml/L

Sulfuric acid 10ml/L

Polyoxyethylene oxypropylene glycerin (molecular weight 8000) 0.1mg/L

PO ₁₀ -EO ₄₂ -PO ₁₀ 30g/L

Octyl alcohol polyoxyethylene ether (molecular weight 2000) 0.01g/L

Hydroquinone + malic acid 10g/L

Temperature 25°C

Example 3

Tin methanesulfonate 75g/L

Methanesulfonic acid 100ml/L

Sulfuric acid 15ml/L

Polyoxyethylene oxypropylene glycerin (molecular weight 12000) 0.1mg/L

EO ₃₀ -PO ₃₀ 15g/L

Octyl alcohol polyoxyethylene ether (molecular weight 8000) 15g/L

Hydroquinone + tartaric acid 20g/L

Temperature 45°C

Plating solution performance test

1) Hull groove test piece test. 267mL of plating solution is used for testing, and the test piece is made of cold-rolled steel plate with a length of 100mm and a height of 70mm. The experimental conditions are 45°C, 2A, 2min, without convective stirring. After the sample is electroplated, take out the deionized water, wash and dry it, and measure the width of the burnt area of the coating. The photos of the Hull test piece of the formulations of Examples 1, 2, and 3 are shown in Figures 1-3. Under static conditions, the limiting current density of the plating solution is as high as 8.5A/dm ² , and there is no unqualified coating in the entire current density area, which can meet the current tin plating process.

2) Deep plating ability test. Using the inner hole method, the test piece adopts a copper tube with an inner diameter of 10mm and a length of 50mm. When plating, the tube hole is used to face the anode plate vertically, and the tube opening is ^100mm away from the anode. Take out the cathode of the round tube, wash and dry it, cut it along the axial direction, measure the plating depth of the tube hole, and evaluate the deep plating ability.

Use the copper tube that the additive formula of embodiment 1 formula is made into the copper pipe plated to form to cut open and find, all go up tin metal in the inner hole of copper tube, illustrate that the plating solution that the additive formula that embodiment 1 provides is made into has good deep-plating ability.

3) Dispersion ability test. Measured by the far and near cathode method, the plating tank uses a transparent plexiglass rectangular tank (the inner cavity size is 150mm×50mm×70mm), and five small slots are evenly opened on both sides of the tank for inserting the cathode, and the cathode adopts a 0.17mm thickness Cold-rolled steel plate with a size of 5.5mm×110mm, the non-working surface is sealed with insulating tape, and a perforated anode with the same size as the cathode is used to facilitate the flow of the plating solution. The test current density is 1.0A/dm ² , the anode is placed between the two cathode test pieces, the distance ratio between the far cathode and the near cathode and the anode is 2:1, after electroplating at 45°C for 10 minutes, the cathode is taken out and cleaned, weighed Measure the increment of deposited metal on the far and near cathode, and calculate the dispersion ability of the plating solution according to the following formula.

,

In the formula: T——dispersion ability, %;

K——the distance ratio between the far cathode and the near cathode and the anode;

m1——the mass of metal deposited near the cathode, g;

m2—the mass of metal deposited on the far cathode, g.

The additive that embodiment 1 provides tests throwing ability 3 times, and data is as table 1:

surface Example 1 Parallel dispersive ability test result for 3 times

Coating performance test

The cold-rolled steel plate using the wet-tempering process is the research object. There are not only rolling lines but also rolling pits on the surface, which has extremely high requirements on the performance of the additives and baths for high-speed electroplating tin. Figures 4-6 are the SEM photos of the 0.7 g/m ² tinplate obtained in Example 1 under the condition of a current density of 15.0 A/dm ² and the local energy spectrum analysis data of the SEM photos. The results show that: under the condition of ^15.0A /dm2, the atomic percentages of tin in the rolling direction of the tin plate and the pit part are 25.44% and 35.88%, respectively, and the tin plating amount at the pit is 0.7g/ ^m2 . If it is higher than the rolling line, the plating solution has a certain leveling ability, which is conducive to further reducing the amount of tin plating and saving tin resources.

Figures 8-11 are the SEM photos of the 1.1g/ ^m2 tinplate obtained under different current densities in Example 1 and the local energy spectra of the SEM photos of the 1.1g/ ^m2 coated tinplate obtained at ^15.0A /dm2 analyze data. The results showed that under the conditions of three current densities, the coating was uniform and fine, without exposed plating, and the tin grains were fine. The 1.1g/m2 tin ^- plated steel sheet obtained under the condition of ^15.0A /dm2 has tin atomic percentages of 62.25% and Sn62.17% in the rolling direction of the tin plate and in the pit, respectively, which is significantly higher than that of the 0.7g/ ^m2 coating , the difference between the tin atomic percentage at the pit and the rolling line is further reduced, and the thickness is uniform. It can be concluded that the plating solution provided by Example 1 has excellent performance, uniform and fine plating, and is suitable for a high-speed tinning process.

Figures 12-14 are 6000 times SEM photos of 1.1g/m ² tinplate obtained in Examples 1, 2, and 3 under the condition of 15.0A/dm ² ; according to the electron microscope photos, it can be seen that the crystal structure of the coating is regular and uniform without defects .

Claims (6)

1. one kind is used for high-speed tin plating plating solution, it is characterized in that described plating solution includes following composition: 5-100g/L tin methane sulfonate, 10-100mL/L pyrovinic acid, 0.1-20ml/L sulphuric acid, 0.1-200mg/L defoamer, 10-50g/L carefully brilliant agent, 0.01-20g/L walk agent, 0.1-40g/L antioxidant, and described defoamer is polyoxyethylene oxypropylene glycerol；Described thin brilliant agent is MO_x-EO_y、PO_x-EO_y、MO_x-EO_y-MO_z、EO_x-MO_y-EO_z、MO_x-EO_y-PO_z、EO_x-MO_y-PO_z、EO_x-PO_y-MO_zOr PO_x-EO_y-PO_z, wherein MO to be methoxyl group, EO be ethyoxyl, PO are propoxyl group；X, y, z is the degree of polymerization of MO, EO, PO of block copolymer；X, y, z range for 1-60；The described agent that walks is alkyl alcohol ethoxylates.

2. according to claim 1 for high-speed tin plating plating solution, it is characterised in that the molecular weight of described polyoxyethylene oxypropylene glycerol is 500-15000.

3. according to claim 1 for high-speed tin plating plating solution, it is characterised in that described thin brilliant agent is MO_mEO_nPO_tRandom copolymer, wherein MO to be methoxyl group, EO be ethyoxyl, PO are propoxyl group, and m, n, t are the unit number of MO, EO, PO of random copolymer, m, n and t range for 1-60.

4. according to claim 1 or 3 for high-speed tin plating plating solution, it is characterised in that described thin brilliant agent EO mass content is at 5-90%, and polymer molecular weight is between 2000-10000, and density is at 1.10 ± 0.10g/cm³, cloud point is at 55-95 DEG C.

5. according to claim 1 for high-speed tin plating plating solution, it is characterised in that described in the agent structural formula that walks be R-O-(CH₂CH₂O) n-H, R are the branched hydrocarbyl of saturated C7 ~ 13, and n is within 60-280.

6. according to claim 1 for high-speed tin plating plating solution, it is characterised in that described antioxidant is any two kinds in hydroquinone, catechol, resorcinol, ascorbic acid, malic acid, citric acid, tartaric acid.