A micro-electrolysis process for accelerating rust layer formation on steel surfaces

Abstract

This invention relates to a micro-electrolysis process for accelerating the formation of rust on steel surfaces, comprising: 1) uniformly activating the steel surface; 2) placing the steel as the anode in the anodic electrolysis zone and an inert electrode as the cathode in the cathodic electrolysis zone; connecting the steel and the inert electrode to a DC adjustable voltage power supply; 3) introducing oxygen into the bottom of the electrolyte in the anodic electrolysis zone through a flow meter and a gas guide pipe; 4) turning on the DC adjustable voltage power supply to electrolyze the steel at the anode until an anti-corrosion rust layer is formed on the steel surface; 5) removing the micro-electrolyzed steel. This invention employs a uniform surface activation treatment before electrolysis combined with a micro-electrolysis process to achieve rapid formation of a rust layer on the steel surface. The resulting rust layer is uniform and compact, thus achieving superior corrosion resistance. It fundamentally solves the maintenance problems encountered during steel application, reduces application costs, enhances the international competitiveness of steel, and yields significant economic and environmental benefits.

Description

Technical Field

[0001] This invention relates to the field of steel surface treatment technology, and in particular to a micro-electrolysis process for accelerating the formation of rust on steel surfaces. Background Technology

[0002] The most prominent advantage of steel is that it can be used without painting. The concept of using it bare is "rust prevention with rust". That is, under long-term exposure, a dense and continuous protective rust layer can be formed between the loose external corrosion product layer on its surface and the substrate. This rust layer has good stability and fine and dense structure, which can effectively isolate the contact between the corrosive medium and the steel substrate, inhibit the corrosion of the internal steel, and thus effectively block the penetration and diffusion of the corrosive medium.

[0003] However, it takes at least 3 to 5 years for steel to form a stable rust layer in the natural environment. Furthermore, in the initial stages of use, rust dripping and spreading can pollute the environment (commonly referred to as "running rust"), significantly affecting the uniformity of the steel's color and polluting the surrounding environment. Therefore, it is necessary to accelerate rust formation on the steel surface through electrolysis or to apply an electroplating coating. Electroplating, however, requires heavy metals such as Ni, Cr, and Co, which is not only costly but also prone to environmental pollution, failing to meet production and environmental protection requirements. In contrast, using micro-electrolysis to accelerate rust formation on the steel surface is not only cost-effective and environmentally friendly but also hinders the intrusion of corrosive ions, reduces the formation of unstable and loose phases, and promotes the formation of dense and stable phases, rapidly forming a protective rust layer on the steel surface. This allows the steel to be used for extended periods in industrial atmospheric environments.

[0004] However, since steel is covered with an oxide layer when it leaves the factory, if surface pretreatment is not performed before electrolytic treatment to accelerate rust formation, the electrolytic process will be uneven and incomplete, severely affecting the quality of the steel surface stabilization treatment and seriously impacting the subsequent industrial application of the steel. Existing surface pretreatment technologies before electrolysis mostly involve removing iron oxide scale from the steel surface. Methods include pickling and sandblasting, which are complex processes, increase costs, and can easily cause environmental pollution.

[0005] Chinese invention patent CN102925884B discloses a "method for spraying pretreatment to accelerate the stabilization of rust layer on steel surfaces." The method involves mixing 0.6% NaCl, 0.9% FeSO4, 0.6% CuSO4, and 0.9% NaHSO4 by weight with water to obtain a surface treatment agent, which is then sprayed onto the steel surface. The chemical substances in the solution react with the steel substrate to form a uniform and dense protective rust layer, making the steel more aesthetically pleasing during use and preventing rust solution runoff, thus protecting the environment from pollution. However, the spraying cost is high, and the spraying solution easily clogs the spraying equipment, making widespread adoption difficult.

[0006] Chinese patent application CN115386867A discloses a "method for stabilizing the rust layer of bridge steel with a semi-permeable coating." The method involves immersing steel with removed surface oxide scale in a prepared stabilizer for 3 days, then applying an 80μm semi-permeable coating to the stabilized rust layer surface, followed by natural drying at room temperature for 24 hours. This method employs a rapid formation of a stable rust layer through a semi-permeable coating on the steel surface, accelerating the formation of a stable rust layer while avoiding the problems of initial rust dripping and atmospheric pollution. However, this method is difficult to apply to large areas, and the coating thickness is insufficient. Furthermore, it suffers from complex production processes, long workflows, and poor continuous production capacity, making large-scale mass production impossible.

[0007] Chinese patent application CN115044280A discloses "A rust-colored coating material suitable for oxide scale coating of hot-rolled steel and its application method." This novel rust-colored coating material eliminates the need for pre-treatment to remove iron oxide scale from the steel surface, simplifies the coating process, and promotes the accelerated formation and stabilization of the rust layer within the coating. Furthermore, during the subsequent peeling process, the coating and rust layer maintain a uniform color, preserving visual appeal. However, the method causes severe environmental pollution when using the composite treatment liquid and introduces numerous impurities into the steel surface, making large-scale application difficult.

[0008] Currently, there are no reports on methods for solving steel surface corrosion problems by using micro-electrolysis to accelerate rust formation on steel surfaces. Therefore, there is an urgent need for a micro-electrolysis process to accelerate rust formation on steel surfaces to compensate for the shortcomings of existing steel surface corrosion protection technologies. Summary of the Invention

[0009] This invention provides a micro-electrolysis process to accelerate the formation of rust on steel surfaces. It employs a uniform surface activation treatment before electrolysis combined with a micro-electrolysis process to achieve rapid formation of a rust layer on the steel surface. The resulting rust layer is uniform and compact, thus achieving superior corrosion resistance. This fundamentally solves the maintenance problems in the application of steel, reduces application costs, enhances the international competitiveness of steel, and yields significant economic and environmental benefits.

[0010] To achieve the above objectives, the present invention employs the following technical solution:

[0011] A micro-electrolysis process for accelerating the formation of rust on steel surfaces includes the following steps:

[0012] 1) Clean the steel surface and dry it. Place the steel in an activator filled with nano-ceramic particles. Inject high-pressure acidic activation liquid into the activator. The acidic activation liquid causes the polygonal nano-ceramic particles to vibrate and scour the steel surface, thus uniformly activating the steel surface.

[0013] 2) The electrolytic cell is filled with electrolyte, and the ion exchange membrane is placed vertically in the middle of the electrolytic cell, dividing the electrolytic cell into an anode electrolysis zone and a cathode electrolysis zone; the surface of the uniformly activated steel is cleaned and dried, and placed in the anode zone as the anode, and the inert electrode is placed in the cathode zone as the cathode; the steel and the inert electrode are connected to a DC adjustable voltage power supply through wires, and both the steel and the inert electrode are submerged in the electrolyte;

[0014] 3) The anode electrolysis zone is equipped with a gas guide pipe. The top end of the gas guide pipe extends above the electrolyte surface and is connected to a flow meter. The bottom end of the gas guide pipe extends to the bottom of the electrolytic cell. Oxygen is introduced into the bottom of the electrolyte through the flow meter and the gas guide pipe.

[0015] 4) Turn on the DC adjustable power supply to electrolyze the steel at the anode until an anti-corrosion rust layer is formed on the surface of the steel;

[0016] 5) Remove the steel after micro-electrolysis, clean the surface and blow it dry.

[0017] Furthermore, in step 1), the acidic activation solution comprises, by weight percentage: 4%–8% metal ion coagulant, 0.25%–1.2% Na2CO3, 0.7%–1.5% CuSO4, and 0.1%–0.8% NaHSO3, with the balance being deionized water; wherein, the metal ion coagulant comprises, by weight percentage of the acidic activation solution: 2%–4% sodium carboxymethyl cellulose and 2%–4% sodium hexametaphosphate.

[0018] Furthermore, in step 2), the inert electrode is a high-purity graphite electrode or a lead electrode.

[0019] Furthermore, in step 2), the electrolyte comprises, by weight percentage: 2%–6% potassium chloride, 0.25%–1.0% citric acid, 0.2%–0.6% sodium citrate, and 0.5%–1.5% sodium bicarbonate, with the remainder being deionized water.

[0020] Furthermore, the electrolyte has a pH value of 2 to 3 and an operating temperature of 25 to 35°C.

[0021] Furthermore, in step 3), the purity of the introduced oxygen is 60% to 80%, and the oxygen flow rate is 30 to 40 ml / min.

[0022] Furthermore, in step 4), the current density of the DC adjustable power supply is 60–90 mA / cm². 3 The micro-electrolysis time is 3 to 5 hours.

[0023] Furthermore, during the electrolysis process in step 4), the pH value of the electrolyte is monitored periodically. If the pH value of the electrolyte is higher than 3, an acidic pH adjuster is added to adjust the pH value to within 2 to 3.

[0024] Furthermore, the pH value of the electrolyte was monitored every 3 to 5 minutes.

[0025] Furthermore, the acidic pH adjuster is a white powder of superior purity NaHSO4.

[0026] Compared with the prior art, the beneficial effects of the present invention are:

[0027] 1) The rapid generation of rust layer on the steel surface is achieved by using a uniform surface activation treatment before electrolysis + micro-electrolysis process. Specifically, the uniformly activated steel is clamped on the anode and immersed in the electrolyte for micro-electrolysis. At the same time, oxygen is introduced into the flow meter. The continuous oxygen supply can accelerate the generation of rust layer on the steel surface and reduce the electrolysis time.

[0028] 2) The pre-electrolysis surface uniform activation treatment described in this invention involves introducing an acidic activation solution into the activator at high pressure and speed, causing polygonal nano-ceramic particles to continuously impact, rub, and scour the steel surface. While removing the hot-rolled oxide layer from the steel surface, this process uniformly activates the steel surface, allowing the particles to gain sufficient energy, causing their electrons to transition from lower ground state energy levels to higher energy levels. This makes the steel surface particles more active, creating favorable conditions for subsequent electrolysis processes.

[0029] 3) An acidic electrolyte composed of potassium chloride, citric acid, sodium citrate, baking soda and deionized water can slightly corrode the steel surface and further accelerate the micro-electrolysis efficiency, promoting the formation of a uniform anti-corrosion rust layer on the steel surface.

[0030] 3) During the micro-electrolysis process, the acidic electrolyte will undergo a slight reaction on the steel surface when stimulated by a micro-current to generate gases such as CO2, which can accelerate the formation of rust on the steel surface and improve the micro-electrolysis effect.

[0031] 4) When steel is used directly without surface treatment, the rust layer forms slowly. Conventional surface treatment processes such as coating and plating are costly and prone to causing pollution. The micro-electrolysis process described in this invention accelerates the formation of rust layer on the surface of steel. Through uniform surface activation treatment before electrolysis combined with micro-electrolysis, a uniform and dense rust layer can be rapidly formed on the surface of steel. This fundamentally solves the maintenance problem during the application of steel, reduces application costs, improves the international competitiveness of steel, and has significant economic and environmental benefits. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the structure of a steel surface uniform activation treatment device according to the present invention.

[0033] Figure 2 This is a schematic diagram of the activator described in this invention.

[0034] Figure 3 This is a schematic diagram of the micro-electrolysis device described in this invention.

[0035] Figure 4 This is a comparison diagram of the effects of micro-electrolysis in the embodiments and comparative examples of the present invention.

[0036] In the diagram: 1. Activator 101. Activator body 102. Top cover 103. Activation solution inlet 104. Activation solution outlet 2. Steel 3. Activation solution storage tank 4. Valve 5. Transfer pump 6. Filter screen 7. Check valve 8. Filter 9. Nano-ceramic particles 10. Steel clamping mechanism 11. Electrolytic cell 12. Ion exchange membrane 13. Electrolyte 14. Inert electrode 15. DC adjustable voltage power supply 16. Gas delivery pipe 17. Flow meter Detailed Implementation

[0037] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings:

[0038] The micro-electrolysis process for accelerating rust formation on steel surfaces as described in this invention includes the following steps:

[0039] 1) Clean the steel surface and dry it. Place the steel in an activator filled with nano-ceramic particles. Inject high-pressure acidic activation liquid into the activator. The acidic activation liquid causes the polygonal nano-ceramic particles to vibrate and scour the steel surface, thus uniformly activating the steel surface.

[0040] 2) The electrolytic cell is filled with electrolyte, and the ion exchange membrane is placed vertically in the middle of the electrolytic cell, dividing the electrolytic cell into an anode electrolysis zone and a cathode electrolysis zone; the surface of the uniformly activated steel is cleaned and dried, and placed in the anode zone as the anode, and the inert electrode is placed in the cathode zone as the cathode; the steel and the inert electrode are connected to a DC adjustable voltage power supply through wires, and both the steel and the inert electrode are submerged in the electrolyte;

[0041] 3) The anode electrolysis zone is equipped with a gas guide pipe. The top end of the gas guide pipe extends above the electrolyte surface and is connected to a flow meter. The bottom end of the gas guide pipe extends to the bottom of the electrolytic cell. Oxygen is introduced into the bottom of the electrolyte through the flow meter and the gas guide pipe.

[0042] 4) Turn on the DC adjustable power supply to electrolyze the steel at the anode until an anti-corrosion rust layer is formed on the surface of the steel;

[0043] 5) Remove the steel after micro-electrolysis, clean the surface and blow it dry.

[0044] Furthermore, in step 1), the acidic activation solution comprises, by weight percentage: 4%–8% metal ion coagulant, 0.25%–1.2% Na2CO3, 0.7%–1.5% CuSO4, and 0.1%–0.8% NaHSO3, with the balance being deionized water; wherein, the metal ion coagulant comprises, by weight percentage of the acidic activation solution: 2%–4% sodium carboxymethyl cellulose and 2%–4% sodium hexametaphosphate.

[0045] Furthermore, in step 2), the inert electrode is a high-purity graphite electrode or a lead electrode.

[0046] Furthermore, in step 2), the electrolyte comprises, by weight percentage: 2%–6% potassium chloride, 0.25%–1.0% citric acid, 0.2%–0.6% sodium citrate, and 0.5%–1.5% sodium bicarbonate, with the remainder being deionized water.

[0047] Furthermore, the electrolyte has a pH value of 2 to 3 and an operating temperature of 25 to 35°C.

[0048] Furthermore, in step 3), the purity of the introduced oxygen is 60% to 80%, and the oxygen flow rate is 30 to 40 ml / min.

[0049] Furthermore, in step 4), the current density of the DC adjustable power supply is 60–90 mA / cm². 3 The micro-electrolysis time is 3 to 5 hours.

[0050] Furthermore, during the electrolysis process in step 4), the pH value of the electrolyte is monitored periodically. If the pH value of the electrolyte is higher than 3, an acidic pH adjuster is added to adjust the pH value to within 2 to 3.

[0051] Furthermore, the pH value of the electrolyte was monitored every 3 to 5 minutes.

[0052] Furthermore, the acidic pH adjuster is a white powder of superior purity NaHSO4.

[0053] The steel surface uniform activation treatment described in this invention refers to the use of a steel surface uniform activation treatment device (patent filed on the same day in a separate application) and a matching acidic activation liquid (patent filed on the same day in a separate application). By introducing a high-speed flowing (pressure of 100-140 bar) acidic activation liquid into the activator, polygonal nano-ceramic particles are continuously impacted and washed against the steel surface. This removes the hot-rolled oxide layer on the steel surface while uniformly activating the steel surface, allowing the particles on the steel surface to obtain sufficient energy. Electrons on the steel surface transition from lower ground state energy levels to higher energy levels, thereby making the steel surface particles more active and creating favorable conditions for subsequent electrolysis processes.

[0054] like Figure 1 , Figure 2 As shown, the steel surface uniform activation treatment device includes an activator 1, a steel clamping mechanism 10, and nano-ceramic particles 9. The activator 1 is a sealed container composed of an activator body 101 and a top cover 102, and the activator body 101 and the top cover 102 are detachably and sealed together. The steel clamping mechanism 9 is located inside the activator body 101 for clamping the steel 2. The activator body 101 is filled with several nano-ceramic particles 9 on the upper and lower sides of the steel 1. Several activation liquid inlets 103 are opened on the top and sides of the activator 1. The activator 1 is connected to the activator storage tank 3 via an activator delivery pipeline. A delivery pump 5 and a valve 4 are installed on the activator delivery pipeline near the activator storage tank 3. Several activator outlets 104 are provided at the bottom of the activator body 101. The activator outlets 104 are connected to the activator storage tank 3 via activator recovery pipelines. Filter screens 6 are provided in the activator 1 corresponding to the activator inlet 103 and the activator outlet 104. One-way valves 7 are respectively installed on the activator delivery pipeline near the activator inlet 103 and the activator recovery pipeline near the activator outlet 104. A filter 8 is installed on the activator recovery pipeline. After cleaning and drying the steel surface, open the top cover 102 and fill a portion of the nano-ceramic particles 9 into the activator body 101; use the steel clamping mechanism 10 to fix the steel 2 into the activator body 101; fill the remaining portion of the nano-ceramic particles 9 on top of the steel 2, and then seal the activator body 101 through the top cover 102; connect the activator 1 to the activation liquid storage tank 3 through the activation liquid delivery pipe and the activation liquid recovery pipe, start the delivery pump 5, and inject high-pressure acidic activation liquid into the activator 1; the acidic activation liquid drives the polygonal nano-ceramic particles 9 to vibrate and scour the surface of the steel 2, and uniformly activate the surface of the steel 2.

[0055] In the acidic activation solution, components such as Na2CO3, CuSO4, and NaHSO3 can create favorable conditions for the subsequent electrolysis process. The metal ion coagulant composed of sodium carboxymethyl cellulose and sodium hexametaphosphate can polymerize and coagulate metal element ions such as Cu and Na in the acidic activation solution, wrapping them around polygonal nano-ceramic particles, thereby improving the uniform activation effect.

[0056] like Figure 3 As shown, the apparatus used in the micro-electrolysis process of this invention includes an electrolytic cell, an ion exchange membrane, an inert electrode, a DC adjustable voltage power supply, a gas delivery pipe, and a flow meter. The electrolytic cell contains electrolyte. The ion exchange membrane is placed vertically in the middle of the electrolytic cell, dividing it into an anodic electrolysis zone and a cathodic electrolysis zone. The ion exchange membrane can only be used for ion exchange; water molecules cannot pass through. The surface of uniformly activated steel is cleaned and dried, and it is placed in the anodic electrolysis zone as the anode. The inert electrode is placed in the cathodic electrolysis zone as the cathode. The steel and inert electrode are connected to the DC adjustable voltage power supply via wires, and both are submerged in the electrolyte. A gas delivery pipe is provided in the anodic electrolysis zone. The top end of the gas delivery pipe extends above the electrolyte surface and is connected to the flow meter, while the bottom end extends to the bottom of the electrolytic cell. Oxygen is introduced to the bottom of the electrolyte through the flow meter and the gas delivery pipe.

[0057] To further describe the present invention, the following description is in conjunction with the accompanying drawings. Figure 1-4 The present invention will be specifically illustrated by the embodiments, and the advantages and various effects of the invention will be more clearly presented therein. Those skilled in the art will understand that these specific embodiments are for illustrative purposes only and are not intended to limit the invention.

[0058] Throughout this specification, unless otherwise specified, the terminology used herein should be understood as having the meaning commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In the event of any conflict, this specification shall prevail.

[0059] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0060] The following comparisons show the effects of micro-electrolysis on steel in Comparative Example 1 and Examples 1-3. Figure 4 As shown.

[0061] Comparative Example 1

[0062] A uniform activation treatment process is used to uniformly activate the steel surface. After activation, the steel is placed outdoors in an unobstructed environment to allow a rust layer to form naturally. After 2-3 months, a slight yellowish rust color appears on the steel surface. The time required for a uniform rust layer to form is 1-2 years, with a thickness of 20 micrometers, adhesion level 1, impact resistance of 150cm, and a color difference value ΔE of 7 between different parts of the steel surface. Issues affecting aesthetics include uneven color and rust runoff.

[0063]

Example 1

[0064] The uniformly activated steel is subjected to micro-electrolysis treatment using a micro-electrolysis process, as detailed below:

[0065] 1. Clean and dry the steel surface, then place the steel in an activator filled with nano-ceramic particles; inject high-pressure acidic activation solution into the activator; the acidic activation solution causes the polygonal nano-ceramic particles to vibrate and scour the steel surface, uniformly activating the steel surface; the acidic activation solution, by weight percentage, includes: sodium carboxymethyl cellulose 2.6%, sodium hexametaphosphate 2.4%, Na2CO3 0.82%, CuSO4 1.05%, and NaHSO3 0.66%, with the balance being deionized water;

[0066] 2. Rinse the uniformly activated steel surface with deionized water and dry it. Use the steel as the anode and immerse it in the electrolyte in the anodic electrolysis zone. Immerse the high-purity graphite electrode as the cathode in the electrolyte in the cathodic electrolysis zone. Connect the steel and the high-purity graphite electrode to a DC adjustable voltage power supply via wires. The electrolyte, by weight percentage, comprises: 2wt% potassium chloride, 0.25wt% citric acid, 0.2wt% sodium citrate, and 0.5wt% sodium bicarbonate, with the balance being deionized water. The pH of the electrolyte is 2.5; the operating temperature is 25℃.

[0067] 3. Oxygen is introduced into the gas tube through the flow meter. The oxygen flows out from the bottom of the electrolyte. The oxygen purity is 60% and the oxygen flow rate is 30 ml / min.

[0068] 4. Turn on the DC adjustable power supply to electrolyze the anode (steel). This accelerates the formation of an anti-corrosion rust layer on its surface; the power supply current density is 60 mA / cm². 3 The electrolysis time is 3 hours. During the electrolysis process, the pH value of the electrolyte is monitored every 3 minutes. If the pH value of the electrolyte is higher than 3, an acidic pH adjuster (white powder, high-purity NaHSO4) is added to adjust the pH value to 2-3.

[0069] 5. Remove the steel after micro-electrolysis, clean the surface with deionized water and then blow it dry.

[0070] The rust layer formed on the steel surface after micro-electrolysis is 70 micrometers thick. It takes 3 hours for the rust layer to evenly cover the steel surface. The adhesion is grade 0, the impact resistance is 250cm, and the color difference value ΔE of different parts of the steel surface is 5. No problems affecting the appearance, such as uneven color or rust water flow, were found.

[0071]

Example 2

[0072] The uniformly activated steel is subjected to micro-electrolysis treatment using a micro-electrolysis process, as detailed below:

[0073] 1. Clean and dry the steel surface, then place the steel in an activator filled with nano-ceramic particles; inject high-pressure acidic activation solution into the activator; the acidic activation solution causes the polygonal nano-ceramic particles to vibrate and scour the steel surface, uniformly activating the steel surface; the acidic activation solution, by weight percentage, includes: sodium carboxymethyl cellulose 3.3%, sodium hexametaphosphate 2.8%, Na2CO3 0.9%, CuSO4 1.3%, and NaHSO3 0.35%, with the remainder being deionized water;

[0074] 2. Rinse the uniformly activated steel surface with deionized water and dry it. Use the steel as the anode and immerse it in the electrolyte in the anodic electrolysis zone. Immerse the high-purity graphite electrode as the cathode in the electrolyte in the cathodic electrolysis zone. Connect the steel and the high-purity graphite electrode to a DC adjustable voltage power supply via wires. The electrolyte, by weight percentage, comprises: 6 wt% potassium chloride, 1.0 wt% citric acid, 0.6 wt% sodium citrate, and 1.5 wt% sodium bicarbonate, with the balance being deionized water. The pH of the electrolyte is 2.8; the operating temperature is 35℃.

[0075] 3. Oxygen is introduced into the gas tube through the flow meter. The oxygen flows out from the bottom of the electrolyte. The oxygen purity is 80% and the oxygen flow rate is 40 ml / min.

[0076] 4. Turn on the DC adjustable power supply to electrolyze the anode (steel). This accelerates the formation of an anti-corrosion rust layer on its surface; the power supply current density is 90 mA / cm². 3 The electrolysis time is 5 hours. During the electrolysis process, the pH value of the electrolyte is monitored every 5 minutes. If the pH value of the electrolyte is higher than 3, an acidic pH adjuster (white powder, high-purity NaHSO4) is added to adjust the pH value to 2-3.

[0077] 5. Remove the steel after micro-electrolysis, clean the surface with deionized water and then blow it dry.

[0078] The rust layer formed on the surface of the steel after micro-electrolysis is 75 micrometers thick. It takes 3.5 hours for the rust layer to evenly cover the steel surface. The adhesion is grade 0, the impact resistance is 300cm, and the color difference value ΔE of different parts of the steel surface is 4. There are no problems affecting the appearance, such as uneven color or rust water flowing.

[0079]

Example 3

[0080] The uniformly activated steel is subjected to micro-electrolysis treatment using a micro-electrolysis process, as detailed below:

[0081] 1. Clean and dry the steel surface, then place the steel in an activator filled with nano-ceramic particles; inject high-pressure acidic activation liquid into the activator; the acidic activation liquid causes the polygonal nano-ceramic particles to vibrate and scour the steel surface, uniformly activating the steel surface; the acidic activation liquid, by weight percentage, includes: sodium carboxymethyl cellulose 3.4%, sodium hexametaphosphate 3.2%, Na2CO3 0.55%, CuSO4 0.86%, and NaHSO3 0.27%, with the balance being deionized water;

[0082] 2. Rinse the uniformly activated steel surface with deionized water and dry it. Use the steel as the anode and immerse it in the electrolyte in the anodic electrolysis zone. Immerse the high-purity graphite electrode as the cathode in the electrolyte in the cathodic electrolysis zone. Connect the steel and the high-purity graphite electrode to a DC adjustable voltage power supply via wires. The electrolyte, by weight percentage, comprises: 4wt% potassium chloride, 0.6wt% citric acid, 0.4wt% sodium citrate, and 0.9wt% sodium bicarbonate, with the balance being deionized water. The pH of the electrolyte is 2.2; the operating temperature is 30℃.

[0083] 3. Oxygen is introduced into the gas tube through the flow meter. The oxygen flows out from the bottom of the electrolyte. The oxygen purity is 70% and the oxygen flow rate is 35 ml / min.

[0084] 4. Turn on the DC adjustable power supply to electrolyze the anode (steel). This accelerates the formation of an anti-corrosion rust layer on its surface; the power supply current density is 75 mA / cm². 3 The electrolysis time is 4 hours. During the electrolysis process, the pH value of the electrolyte is monitored every 4 minutes. If the pH value of the electrolyte is higher than 3, an acidic pH adjuster (white powdered high-purity NaHSO4) is added to adjust the pH value to 2-3.

[0085] 5. Remove the steel after micro-electrolysis, clean the surface with deionized water and then blow it dry.

[0086] The rust layer formed on the surface of the steel after micro-electrolysis is 68 micrometers thick. It takes 2.7 hours for the rust layer to evenly cover the steel surface. The adhesion is grade 0, the impact resistance is 230cm, and the color difference value ΔE of different parts of the steel surface is 6. No problems such as uneven appearance color or rust water flow that affect the appearance have been found.

[0087] The above comparison demonstrates that the micro-electrolysis process for accelerating rust formation on steel surfaces, as described in this invention, can overcome the shortcomings of existing steel surface corrosion protection technologies, eliminate the negative impacts of traditional electroplating processes that require heavy metals such as Ni, Cr, and Co, and significantly reduce the application and maintenance costs of steel. This has significant engineering application value for steel used in industrial atmospheric environments. It is also of great importance for saving resources and energy and improving the international competitiveness of steel.

[0088] Those skilled in the art should recognize that the above embodiments are merely illustrative of the present invention and are not intended to limit the present invention. For example, the composition of the electrolyte, the magnitude of the power supply current, the micro-electrolysis time, the oxygen flow rate, etc., are also limited to the essential scope of the present invention. Any changes or modifications to the above embodiments will fall within the protection scope of the claims of the present invention.

[0089] The present invention also includes the following embodiments, wherein the electrolyte composition (weight percentage) in each embodiment is shown in Table 1, and the process parameters of the micro-electrolysis process are shown in Table 2.

[0090] Table 1

[0091] Example 4 2.6 0.87 0.39 0.81 margin Example 5 2.2 0.28 0.57 0.64 margin Example 6 4.7 0.32 0.44 0.72 margin Example 7 5.3 0.85 0.51 1.22 margin Example 8 3.6 0.77 0.27 1.36 margin Example 9 3.1 0.65 0.25 1.47 margin Example 10 5.8 0.94 0.33 1.08 margin

[0092] Table 2

[0093]

[0094] It should be understood that the endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0095] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A process for accelerating the formation of rust layer on the surface of steel material by micro-electrolysis, characterized in that, Includes the following steps: 1) Clean the steel surface and dry it. Place the steel in an activator filled with nano-ceramic particles. Inject high-pressure acidic activation liquid into the activator. The acidic activation liquid causes the polygonal nano-ceramic particles to vibrate and scour the steel surface, thus uniformly activating the steel surface. The acidic activation solution comprises, by weight percentage: 4%–8% metal ion coagulant, 0.25%–1.2% Na2CO3, 0.7%–1.5% CuSO4, and 0.1%–0.8% NaHSO3, with the balance being deionized water; wherein, the metal ion coagulant comprises, by weight percentage, 2%–4% sodium carboxymethyl cellulose and 2%–4% sodium hexametaphosphate. 2) The electrolytic cell is filled with electrolyte. The ion exchange membrane is placed vertically in the middle of the electrolytic cell, dividing the cell into an anode electrolysis zone and a cathode electrolysis zone. The surface of the uniformly activated steel is cleaned and dried, and placed in the anode zone as the anode. The inert electrode is placed in the cathode zone as the cathode. The steel and the inert electrode are connected to a DC adjustable voltage power supply through wires, and both the steel and the inert electrode are submerged in the electrolyte. The electrolyte, by weight percentage, includes: potassium chloride 2%–6%, citric acid 0.25%–1.0%, sodium citrate 0.2%–0.6%, and sodium bicarbonate 0.5%–1.5%, with the remainder being deionized water. 3) The anode electrolysis zone is equipped with a gas guide pipe. The top end of the gas guide pipe extends above the electrolyte surface and is connected to a flow meter. The bottom end of the gas guide pipe extends to the bottom of the electrolytic cell. Oxygen is introduced into the bottom of the electrolyte through the flow meter and the gas guide pipe. 4) Turn on the DC adjustable power supply to electrolyze the steel at the anode until an anti-corrosion rust layer is formed on the surface of the steel; 5) Remove the steel after micro-electrolysis, clean the surface and blow it dry.

2. A process for accelerating the formation of rust layer on the surface of steel material by micro-electrolysis as claimed in claim 1 wherein, In step 2), the inert electrode is a high-purity graphite electrode or a lead electrode.

3. The process as claimed in claim 1, wherein the process for accelerating the formation of rust layer on the surface of steel material is characterized by, The electrolyte has a pH value of 2 to 3 and an operating temperature of 25 to 35°C.

4. The process as claimed in claim 1, wherein the process for accelerating the formation of rust layer on the surface of steel material is characterized by, In step 3), the purity of the introduced oxygen is 60% to 80%, and the oxygen flow rate is 30 to 40 ml / min.

5. The process as claimed in claim 1, wherein the process for accelerating the formation of rust layer on the surface of steel material by micro electrolysis is characterized by, The current density of the direct current adjustable voltage power supply in the step 4) is 60-90 mA / cm 3 , and the micro-electrolysis time is 3-5 h.

6. The micro-electrolysis process for accelerating rust formation on steel surfaces according to claim 1, characterized in that, During the electrolysis process in step 4), the pH value of the electrolyte is monitored periodically. If the pH value of the electrolyte is higher than 3, an acidic pH adjuster is added to adjust the pH value to within 2 to 3.

7. The micro-electrolysis process for accelerating rust formation on steel surfaces according to claim 6, characterized in that, Monitor the pH value of the electrolyte every 3 to 5 minutes.

8. The micro-electrolysis process for accelerating rust formation on steel surfaces according to claim 6, characterized in that, The acidic pH adjuster is a white powder of superior grade NaHSO4.

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