阅读说明：本技术 一种彩色钝化镀锌钢板及其制作方法 (Colorful passivated galvanized steel sheet and manufacturing method thereof ) 是由 安龙龙 于 2020-12-30 设计创作，主要内容包括：本发明的技术方案公开了一种彩色钝化镀锌钢板包括基板、镀锌层和彩色钝化层；基板的表面依次覆盖镀锌层和彩色钝化层；镀锌层是由基板在镀液中通过电镀得到,镀液原料组成包括ZnCl-2、AlCl-3、KCl、硼酸、光亮剂和柔软剂,彩色钝化层是由表面覆盖镀锌层的基板在彩色钝化液中通过钝化得到,彩色钝化液的原料组成包括硅酸钠、双氧水、氟化物、羟基乙叉二膦酸、硅烷偶联剂、磷酸、聚乙烯醚和硫酸镍,其余为去离子水；得到耐腐蚀性好、膜层附着性好的彩色钝化镀锌钢板。(The technical scheme of the invention discloses a colorful passivated galvanized steel sheet, which comprises a substrate, a galvanized layer and a colorful passivated layer; the surface of the substrate is sequentially covered with a zinc coating and a colorful passivation layer; the zinc coating is obtained by electroplating a substrate in a plating solution, and the plating solution comprises ZnCl 2 、AlCl 3 The color passivation layer is obtained by passivating a substrate covered with a zinc coating layer on the surface in a color passivation solution, and the color passivation solution comprises raw materials of sodium silicate, hydrogen peroxide, fluoride, hydroxy ethylidene diphosphonic acid, a silane coupling agent, phosphoric acid, polyvinyl ether and nickel sulfate, and the balance of deionized water; the obtained colorful passivated galvanized steel sheet with good corrosion resistance and good film adhesion。)

1. A colorful passivated galvanized steel sheet is characterized in that: comprises a substrate, a zinc coating and a colorful passivation layer; the surface of the substrate is sequentially covered with a zinc coating and a colorful passivation layer;

the zinc coating is obtained by electroplating a substrate in a plating solution, and the plating solution comprises ZnCl as a raw material₂ 65～75g/L、AlCl₃0.8-1.1 mg/L, KCl 160-180 g/L, 26-32 g/L boric acid, 0.3-0.6 ml/L brightener and 15-18 ml/L softener, wherein the pH value is 5.0-5.5;

the color passivation layer is obtained by passivating a substrate with a zinc coating covering the surface in a color passivation solution, and the color passivation solution comprises 26-32 g/L of sodium silicate, 8-12 mL/L of hydrogen peroxide, 3-6 g/L of fluoride, 3-6 mL/L of hydroxyl ethylidene diphosphonic acid, 6-8 g/L of silane coupling agent, 6-10 mL/L of phosphoric acid, 2-5 mL/L of polyvinyl ether and 1-1.5 g/L of nickel sulfate, the balance of deionized water, and the pH value is 2.0-2.5.

2. A color passivated galvanized steel sheet according to claim 1 characterized in that: the substrate is a low-carbon steel plate.

3. A color passivated galvanized steel sheet according to claim 1 characterized in that: the fluoride is potassium fluoride or sodium fluoride.

4. A color passivated galvanized steel sheet according to claim 1 characterized in that: the silane coupling agent is aminosilane.

5. The method for manufacturing the color passivated galvanized steel sheet according to claim 1, characterized in that: the method comprises the following steps:

s1, performing alkali washing, electrolytic degreasing, rinsing and drying treatment on the substrate to obtain a pretreated substrate;

s2, preparing plating solution, and mixing ZnCl₂、AlCl₃The KCl, the brightening agent and the softening agent are uniformly mixed, and the pH value of the plating solution is adjusted through boric acid to obtain the plating solution;

s3, putting the pretreated substrate into a plating solution for electroplating treatment, wherein the current density is1.5A/dm²At room temperature and for 20-30 min, obtaining a substrate with a surface covered with a zinc coating;

s4, preparing a brightening solution and adding chemically pure HNO₃Preparing HNO with 3 percent of mass concentration with water₃Obtaining a brightening solution;

s5, preparing a color passivation solution, adding 50ml of deionized water into a beaker, then respectively adding sodium silicate, hydrogen peroxide, fluoride, hydroxyethylidene diphosphonic acid, a silane coupling agent, polyvinyl ether and nickel sulfate into the deionized water, stirring uniformly until the sodium silicate, the hydrogen peroxide, the fluoride, the hydroxyethylidene diphosphonic acid, the silane coupling agent, the polyvinyl ether and the nickel sulfate are completely dissolved, adding phosphoric acid, stirring uniformly, finally supplementing the deionized water, adding dilute nitric acid to adjust the pH value to 2.0-2.5, and obtaining the color passivation solution with the total volume of 1L;

and S6, cleaning the substrate covered with the zinc coating layer in the S3, immersing the substrate into a bright dipping solution, standing at room temperature for 3-5S, taking out the substrate, cleaning, immersing the substrate into a color passivation solution, immersing the substrate in the color passivation solution for 30-50S at room temperature, taking out the substrate, cleaning, and drying to obtain the color passivated galvanized steel sheet.

6. The method for manufacturing the colorful passivated galvanized steel sheet according to claim 5, characterized in that: the cleaning method in S6 is to wash the substrate with tap water or rinse the substrate in a tank or a pool filled with clean water until the substrate surface covered with the zinc plating layer is cleaned.

7. The method for manufacturing the colorful passivated galvanized steel sheet according to claim 5, characterized in that: and the drying method in the S6 comprises the steps of naturally airing, drying by a blower or drying by a constant temperature oven at 60 ℃.

Technical Field

The invention relates to the technical field of galvanized steel sheet processing, in particular to a colorful passivated galvanized steel sheet and a manufacturing method thereof.

Background

The color passivation technology is a chemical conversion film processing method, after hot-dip plating or electroplating process, the zinc layer with surface activation state is changed into passivation state, so that the metal dissolution is slowed down, and the corrosion resistance of the plated piece is improved.

The color passivation technology generally adopts chromate solution for passivation and chromium-free passivation, the chromate solution has certain toxicity when being passivated, and the chromium-free passivation adopts titanium salt, silicate, molybdate, tungstate, rare earth metal and the like for passivation, so that the color passivation technology has the advantages of being green and environment-friendly. But the film layers generated by chromium-free passivation have poor binding force, the passivation layer is thin and is easy to become fluffy and peel off, and the corrosion resistance of the film layers is poor. The color coating is usually carried out after the passivation, the treatment process is complex and tedious, a large amount of waste water and waste liquid can be generated in the treatment process, and the environment is greatly polluted. Among them, silicate passivation has a good application prospect, but stability and corrosion resistance need to be improved.

Disclosure of Invention

In order to solve the technical problems in the prior art, the invention provides a colorful passivated galvanized steel sheet and a manufacturing method thereof.

The technical scheme of the invention is as follows: a colorful passivated galvanized steel sheet comprises a substrate, a galvanized layer and a colorful passivation layer; the surface of the substrate is sequentially covered with a zinc coating and a colorful passivation layer;

the substrate is a low-carbon steel plate;

the zinc coating is obtained by electroplating a substrate in a plating solution, and the plating solution comprises ZnCl as a raw material₂ 65～75g/L、AlCl₃0.8-1.1 mg/L, KCl 160-180 g/L, 26-32 g/L boric acid, 0.3-0.6 ml/L brightener and 15-18 ml/L softener, wherein the pH value is 5.0-5.5;

the color passivation layer is obtained by passivating a substrate with a zinc coating covering the surface in a color passivation solution, and the color passivation solution comprises 26-32 g/L of sodium silicate, 8-12 mL/L of hydrogen peroxide, 3-6 g/L of fluoride, 3-6 mL/L of hydroxyl ethylidene diphosphonic acid, 6-8 g/L of silane coupling agent, 6-10 mL/L of phosphoric acid, 2-5 mL/L of polyvinyl ether and 1-1.5 g/L of nickel sulfate, the balance of deionized water, and the pH value is 2.0-2.5;

the fluoride is potassium fluoride or sodium fluoride;

the silane coupling agent is aminosilane;

a manufacturing method of a colorful passivated galvanized steel sheet comprises the following steps:

s1, performing alkali washing, electrolytic degreasing, rinsing and drying treatment on the substrate to obtain a pretreated substrate;

s2, preparing plating solution, and mixing ZnCl₂、AlCl₃The KCl, the brightening agent and the softening agent are uniformly mixed, and the pH value of the plating solution is adjusted through boric acid to obtain the plating solution;

s3, putting the pretreated substrate into a plating solution for electroplating treatment, wherein the current density is 1.5A/dm²At room temperature and for 20-30 min, obtaining a substrate with a surface covered with a zinc coating;

s4, preparing a brightening solution and adding chemically pure HNO₃Preparing HNO with 3 percent of mass concentration with water₃Obtaining a brightening solution;

s5, preparing a color passivation solution, adding 50ml of deionized water into a beaker, then respectively adding sodium silicate, hydrogen peroxide, fluoride, hydroxyethylidene diphosphonic acid, a silane coupling agent, polyvinyl ether and nickel sulfate into the deionized water, stirring uniformly until the sodium silicate, the hydrogen peroxide, the fluoride, the hydroxyethylidene diphosphonic acid, the silane coupling agent, the polyvinyl ether and the nickel sulfate are completely dissolved, adding phosphoric acid, stirring uniformly, finally supplementing the deionized water, adding dilute nitric acid to adjust the pH value to 2.0-2.5, and obtaining the color passivation solution with the total volume of 1L;

and S6, cleaning the substrate covered with the zinc coating layer in the S3, immersing the substrate into a bright dipping solution, standing at room temperature for 3-5S, taking out the substrate, cleaning, immersing the substrate into a color passivation solution, immersing the substrate in the color passivation solution for 30-50S at room temperature, taking out the substrate, cleaning, and drying to obtain the color passivated galvanized steel sheet.

Further, the cleaning method in S6 is to wash the substrate surface covered with the zinc plating layer with tap water, or rinse the substrate surface in a tank or a pool filled with clean water until the substrate surface is cleaned.

Further, the drying method in S6 is natural drying, drying by a blower, or drying at a constant temperature of 60 ℃ in a constant temperature oven.

The sodium silicate reacts with hydroxy ethylidene diphosphonic acid and phosphoric acid in the colorful passivated galvanized steel sheet to form a layer of titanium dioxide which is difficult to dissolve in water on the surface of a galvanized layer, and the radical energy in the hydroxy ethylidene diphosphonic acid can be neutralizedThe zinc ions in the zinc coating are complexed to form a compact intermediate film with strong viscosity, and the intermediate film and the titanium dioxide hinge form a compact passive film which is the main body of the passive layer. Hydrogen peroxide is a main oxidant, so that zinc ions are quickly generated on the surface of the zinc coating to participate in film formation, the film formation process is accelerated, and the passivation efficiency is improved. The potassium fluoride or sodium fluoride can control the film forming rate and the film thickness, and improve the stability of the color passivation solution. The silane coupling agent is respectively combined with inorganic matters and zinc ion hybrids on the surface of the zinc coating, and the silane coupling agent is between an inorganic interface and an organic interface, so that a bonding layer of an organic matrix, the silane coupling agent and an inorganic matrix can be formed, the adhesion performance and the film strength are improved, the surface property of the passive film is improved, and the corrosion resistance is further improved. Phosphoric acid as main solvent and H required for film-forming reaction⁺The main source of the zinc-plating solution and the zinc-plating layer generate a phosphating reaction simultaneously, and a continuous water-insoluble firm phosphating film, namely 3Zn, is generated on the surface of the zinc-plating layer²⁺+2PO₃ ⁴—+4H₂O＝Zn₃(PO₄)₂·4H₂And O ↓andthe generated phosphate conversion film further improve the adhesive force and the anti-corrosion capability of the color passivation layer. The polyvinyl ether prevents the sodium silicate from being excessively aggregated and plays a role of a bridge chain in the generation process of the silicon dioxide; and prevents the aggregation of silicon dioxide molecules, thereby producing silicon dioxide with better dispersity and leading the corrosion resistance of the colorful passivation film to be more stable. Nickel sulfate is a colorant that affects the color of the color passivation layer. In addition, the content of aluminum ions added into the plating solution is strictly regulated, and if the amount of the aluminum ions is too large, the corrosion resistance is reduced, and by adding a small amount of aluminum ions into the plating solution, the fluidity of the plating solution is improved, the wetting of the plating solution on a substrate is increased, the binding force between a zinc coating and the substrate is improved, and in addition, the zinc ions are promoted to be more uniformly distributed in the zinc coating, so that the generated passivation film is more uniformly dispersed on the surface of a color passivation layer; and the aluminum ions react with the hydroxyethylidene diphosphonic acid to be combined with the intermediate film formed by the zinc ions, so that the intermediate film has more uniform and stronger viscosity, and a passive film formed by a titanium dioxide hinge is more compact and interacts with a silane coupling agent to form an organic matrix-silane coupling agentIn the agent-inorganic matrix binding layer, aluminum ions and zinc ions are uniformly dispersed, the resistance to the external environment is improved compared with that of a pure zinc ion state, the adhesion performance and the film strength are improved, and the corrosion resistance is further improved.

By adopting the technical scheme, the invention has the following beneficial effects:

(1) the method comprises the steps of passivating an electroplated substrate with a zinc coating on the surface in a colorful passivating solution to obtain a colorful passivating layer; the color passivation solution does not contain chromium and other toxic substances, and the color passivation layer is uniform and bright in color due to the cooperation of sodium silicate and other components, so that the film layer is good in corrosion resistance, high in passivation efficiency and good in adhesion.

(2) The adhesion performance and the film strength of the color passivation layer are improved through the silane coupling agent in the color passivation solution, so that the surface of the passivation layer is more compact, and the corrosion resistance effect is better; the polyvinyl ether prevents the sodium silicate from being excessively gathered, and the generated silicon dioxide is more uniformly dispersed on the surface of the colorful passivation layer, so that the corrosion resistance of the colorful passivation film is more stable.

(3) The operation method is simple, the steps of color coating after passivation are reduced, the effect of color coating the steel plate can be realized, the generation of waste water is reduced, and the environmental pollution is reduced.

Detailed Description

The present invention will be described in further detail with reference to specific examples.

Example 1

A colorful passivated galvanized steel sheet comprises a substrate, a galvanized layer and a colorful passivation layer; the surface of the substrate is sequentially covered with a zinc coating and a colorful passivation layer;

the substrate is a low-carbon steel plate;

the zinc coating is obtained by electroplating a substrate in a plating solution, and the plating solution comprises ZnCl as a raw material₂ 70g/L、AlCl₃1mg/L, KCl 175g/L, boric acid 30g/L, brightener DK-SXG 0.5ml/L and softener DK-SXR 17ml/L, and the pH value is 5.4;

the color passivation layer is obtained by passivating a substrate with a zinc coating covered on the surface in a color passivation solution, wherein the color passivation solution comprises 26g/L of sodium silicate, 8mL/L of hydrogen peroxide, 3g/L of potassium fluoride, 3mL/L of hydroxy ethylidene diphosphonic acid, 6-8 g/L of aminosilane KH, 6mL/L of phosphoric acid, 2mL/L of polyvinyl ether and 1g/L of nickel sulfate, the balance of deionized water, and the pH value is 2.5;

a manufacturing method of a colorful passivated galvanized steel sheet comprises the following steps:

s1, performing alkali washing, electrolytic degreasing, rinsing and drying treatment on the substrate to obtain a pretreated substrate;

s2, preparing plating solution, and mixing ZnCl₂、AlCl₃The KCl, the brightening agent and the softening agent are uniformly mixed, and the pH value of the plating solution is adjusted through boric acid to obtain the plating solution;

s3, putting the pretreated substrate into a plating solution for electroplating treatment, wherein the current density is 1.5A/dm²At room temperature for 30min to obtain a substrate with a zinc coating on the surface;

s4, preparing a brightening solution and adding chemically pure HNO₃Preparing HNO with 3 percent of mass concentration with water₃Obtaining a brightening solution;

s5, preparing a color passivation solution, adding 500ml of deionized water into a beaker, then respectively adding sodium silicate, hydrogen peroxide, potassium fluoride, hydroxyethylidene diphosphonic acid, aminosilane KH-550, polyvinyl ether and nickel sulfate into the deionized water, uniformly stirring until the sodium silicate, the hydrogen peroxide, the potassium fluoride, the hydroxyethylidene diphosphonic acid, the aminosilane KH-550, the polyvinyl ether and the nickel sulfate are completely dissolved, adding phosphoric acid, uniformly stirring, finally supplementing the deionized water, adding dilute nitric acid to adjust the pH value to 2.5, and obtaining the color passivation solution with the total volume of 1L;

and S6, washing the substrate with the surface covered with the zinc coating obtained in the step S3 clean by tap water, immersing the substrate into a bright liquid, staying for 3S at room temperature, taking out the substrate, washing the substrate clean by tap water, immersing the substrate into a color passivation solution, immersing the substrate into the color passivation solution for 30S at room temperature, taking out the substrate, washing the substrate clean by tap water, and drying the substrate by a blower to obtain the color passivated galvanized steel sheet.

Example 2

A colorful passivated galvanized steel sheet comprises a substrate, a galvanized layer and a colorful passivation layer; the surface of the substrate is sequentially covered with a zinc coating and a colorful passivation layer;

the substrate is a low-carbon steel plate;

the zinc coating is obtained by electroplating a substrate in a plating solution, and the plating solution comprises ZnCl as a raw material₂ 75g/L、AlCl₃0.8mg/L, KCl 180g/L, 32g/L boric acid, 0.6ml/L brightener DK-SXG and 18ml/L softener DK-SXR, and the pH value is 5.0;

the color passivation layer is obtained by passivating a substrate with a zinc coating covered on the surface in a color passivation solution, and the color passivation solution comprises 32g/L of sodium silicate, 12mL/L of hydrogen peroxide, 6g/L of sodium fluoride, 6mL/L of hydroxy ethylidene diphosphonic acid, KH-5508 g/L of aminosilane, 10mL/L of phosphoric acid, 5mL/L of polyvinyl ether and 1.5g/L of nickel sulfate, the balance of deionized water, and the pH value is 2.0;

a manufacturing method of a colorful passivated galvanized steel sheet comprises the following steps:

s1, performing alkali washing, electrolytic degreasing, rinsing and drying treatment on the substrate to obtain a pretreated substrate;

s2, preparing plating solution, and mixing ZnCl₂、AlCl₃The KCl, the brightening agent and the softening agent are uniformly mixed, and the pH value of the plating solution is adjusted through boric acid to obtain the plating solution;

s3, putting the pretreated substrate into a plating solution for electroplating treatment, wherein the current density is 1.5A/dm²At room temperature and for 20min, obtaining a substrate with the surface covered with a zinc coating;

s4, preparing a brightening solution and adding chemically pure HNO₃Preparing HNO with 3 percent of mass concentration with water₃Obtaining a brightening solution;

s5, preparing a color passivation solution, adding 500ml of deionized water into a beaker, then respectively adding sodium silicate, hydrogen peroxide, sodium fluoride, hydroxyethylidene diphosphonic acid, aminosilane KH-550, polyvinyl ether and nickel sulfate into the deionized water, uniformly stirring until the sodium silicate, the hydrogen peroxide, the sodium fluoride, the hydroxyethylidene diphosphonic acid, the aminosilane KH-550, the polyvinyl ether and the nickel sulfate are completely dissolved, adding phosphoric acid, uniformly stirring, finally supplementing the deionized water, adding dilute nitric acid to adjust the pH value to 2.0, and obtaining the color passivation solution with the total volume of 1L;

and S6, rinsing the substrate covered with the zinc coating layer in the groove with clean water in the step S3, immersing the substrate into a bright dipping solution, staying for 5S at room temperature, taking out the substrate, rinsing the substrate in the groove with clean water, immersing the substrate into a color passivation solution, soaking the substrate in the color passivation solution for 50S at room temperature, taking out the substrate, rinsing the substrate in the groove with clean water, and naturally airing the substrate to obtain the color passivated galvanized steel sheet.

Comparative example 1

The difference from example 1 is that the color passivating solution is free of polyvinyl ether.

Comparative example 2

The difference from example 1 is that the color passivating solution is free of aminosilane.

Comparative example 3

The difference from example 1 is that the bath is free of AlCl₃。

The neutral salt spray corrosion test is carried out on the color passivated galvanized steel sheets prepared in the examples 1-2 and the comparative examples 1-3, the test conditions are that the mass percent of the sodium chloride salt solution is 5%, the pH value is 6.5-7.0, the spraying amount (in the area of 80cm 2) is 1-2 ml/h, the spraying pressure is 90-100 KPa, the spraying temperature is 35 ℃, the duration is 600h, and obvious corrosion marks appear after the surface of the color passivated galvanized steel sheet is detected for a long time, and the results are shown in the table 1.

TABLE 1 time to white rust in neutral salt spray test

Group of	Example 1	Example 2	Comparative example 1	Comparative example 2	Comparative example 3
						Time	Over 600h	Over 600h	98h	72h	92h

As can be seen from the results in Table 1, the time for obvious corrosion of examples 1 and 2 is much longer than that of comparative examples 1 to 3, which shows that the color passivated galvanized steel sheets of examples 1 and 2 have good corrosion resistance, and the corrosion resistance of comparative examples 1 to 3 is poor, which shows that polyvinyl ether and aminosilane are added into the color passivation solution, and AlCl is added into the plating solution₃And the corrosion resistance of the film layer is improved.

The performance of the color passivated galvanized steel sheets prepared in the examples 1-2 and the comparative examples 1-3 is detected by the following method:

pencil hardness: mitsubishi pencil, 2H does not break.

Gloss: gloss meter, standard: 80 +/-5.

Adhesion force: the blade has no drop-off in hundreds of cases.

Impact resistance: the impact instrument is used for impacting 50KG. CM, and the surface does not crack or fall paint.

The results are shown in Table 2.

TABLE 2 Performance test results

The hardness and gloss of the color passivated galvanized steel sheets of examples 1, 2 and comparative examples 1-3 were good, the adhesion and impact resistance of examples 1-2 and comparative example 1 were good, and the adhesion and impact resistance of comparative example 2 and comparative example 3 were poor, indicating that the film layer adhesion of examples 1-2 was good.