A cleaning tank for cleaning a metal surface, a system including the same, a method of cleaning a metal surface, and applications

Abstract

The present application belongs to the technical field of metal surface cleaning, and specifically discloses a cleaning tank for cleaning metal surfaces, a system comprising the same, a method for cleaning metal surfaces and applications. The method of the present application simultaneously introduces a micro-nano bubble generator, a plasma generating device and an ultrasonic wave generating device, and uses a triple coupling mode to clean the metal surface. The method of the present application can be applied to five types of cleaning conditions, namely, conventional alkaline cleaning, conventional acid cleaning, alkaline electrolysis, acid electrolysis and neutral salt electrolysis, and can cover the whole process of pre-treatment soaking cleaning and precision electrolysis cleaning, thereby greatly improving the cleanliness of workpieces, shortening the cleaning time, reducing the consumption of chemicals and electric energy, reducing the corrosion of the substrate, and being suitable for industrial batch cleaning of precision parts such as carbon steel, stainless steel and aluminum alloy.

Description

Technical Field

[0001] This invention belongs to the field of metal surface cleaning technology, specifically relating to a cleaning tank for cleaning metal surfaces, a system thereof, a method for cleaning metal surfaces, and its application. Background Technology

[0002] Metal workpieces typically undergo a pre-treatment immersion cleaning process before a subsequent precision electrolytic cleaning. The pre-treatment process includes conventional alkaline washing for degreasing and conventional acid washing for removing oxidation and rust. The subsequent process mainly includes three types of precision cleaning: alkaline electrolysis, acid electrolysis, and neutral salt electrolysis. These five types of processes are flexibly selected based on the workpiece material and cleanliness requirements, covering a wide range of needs from general hardware to aerospace components.

[0003] Conventional alkaline washing relies on the saponification and emulsification of greases by alkaline solutions. However, mass transfer mainly depends on natural molecular diffusion, which is inefficient. It results in insufficient wetting of dead corners such as micropores, threads, and crevices in the workpiece, making it difficult to remove thick, hardened oil stains. To achieve the cleaning requirements, it is often necessary to increase the alkali concentration, raise the temperature, and extend the soaking time, leading to high reagent consumption and slow production cycle. Conventional acid washing relies on acid to dissolve metal oxides. However, the dense oxide scale and rust layer formed by heat treatment or rolling hinder mass transfer at the solid-liquid interface, resulting in slow acid penetration. Local accumulation of reaction products reduces acid activity, leading to uneven workpiece surface condition and significant color differences after cleaning. Furthermore, inconsistent surface conditions affect the adhesion of subsequent electroplating or coating.

[0004] While alkaline electrolysis, acid electrolysis, and neutral salt electrolysis can compensate for the insufficient precision of conventional cleaning, each has its own drawbacks. In alkaline electrolysis, the oil film on the workpiece surface hinders ion migration, resulting in delayed film renewal, incomplete removal of stubborn oil stains, and high energy and chemical consumption. Acid electrolysis is prone to localized acid enrichment, leading to over-corrosion of the substrate and surface discoloration. Neutral salt electrolysis has low ion mobility and poor conductivity, resulting in weak electrochemical reactions and limited ability to remove stubborn oil stains and dense passivation layers. It is difficult to remove trace amounts of oil stains and passivation layers, and cannot meet the cleanliness requirements of high-precision parts. Summary of the Invention

[0005] This invention addresses the aforementioned problems in existing technologies by proposing a cleaning tank, a system containing the tank, a method for cleaning metal surfaces, and its application. It utilizes a triple-coupling mode of micro / nano bubble generator, plasma generator, and ultrasonic generator to clean metal surfaces. The method of this invention can be applied to five types of cleaning processes: conventional alkaline washing, conventional acid washing, alkaline electrolysis, acid electrolysis, and neutral salt electrolysis. It covers the entire process from pretreatment immersion cleaning to precision electrolytic cleaning, significantly improving workpiece cleanliness, shortening cleaning time, reducing chemical and energy consumption, and minimizing substrate corrosion. It is suitable for industrial-scale batch cleaning of precision parts made of carbon steel, stainless steel, aluminum alloys, and other materials.

[0006] Specifically, one aspect of the present invention provides a cleaning tank for cleaning metal surfaces, comprising: The tank is used to hold the workpiece to be cleaned. A plasma generator, installed on the side wall of the tank, for introducing active species into the cleaning medium within the tank; and An ultrasonic generator is installed on the side wall and / or bottom of the tank.

[0007] In one or more embodiments, the working gas of the plasma generator is air, oxygen, or nitrogen; the working gas is excited by plasma to generate one or more active species, the active species including one or more of free radicals, atoms, excited-state molecules, ions, and ozone.

[0008] In one or more embodiments, the discharge power of the plasma generator is 30-320W.

[0009] In one or more embodiments, the ultrasonic generator is an ultrasonic titanium alloy vibrating plate.

[0010] In one or more embodiments, the ultrasonic frequency of the ultrasonic generator is 20-40 kHz.

[0011] In one or more embodiments, the ultrasonic power density of the ultrasonic generator is 10-30 W / L.

[0012] Another aspect of the present invention provides a system for cleaning metal surfaces, the system comprising: A mixing tank is used to store cleaning media; A circulating pump is used to transport the cleaning medium from the liquid preparation tank to the micro / nano bubble generator; Micro / nano bubble generator, used to generate micro / nano bubbles; The cleaning tank described in any embodiment of the present invention; A circulating filtration device is used to receive the cleaning medium carrying stripped contaminants flowing out of the cleaning tank and to remove scum from it; and The return pipeline is used to return the cleaning medium filtered by the circulating filter to the liquid preparation tank, so that the cleaning medium is in a state of circulation. The liquid preparation tank, circulating pump, micro-nano bubble generator, cleaning tank, circulating filter device and return pipeline are connected in sequence to form a cleaning medium circulation loop. The system also includes a DC power supply and electrodes, the electrodes including the workpiece to be cleaned and an auxiliary electrode; the DC power supply and the electrodes are connected to form an electrolysis circuit.

[0013] In one or more embodiments, the system further includes a plasma generator disposed in a return line.

[0014] In one or more embodiments, the micro / nano bubble generator produces bubbles with an average particle size of 50 nm-50 μm and a gas flow rate of 0.3-2 m³ / h. 3 / h.

[0015] In one or more embodiments, the DC voltage of the DC power supply is 3-15V.

[0016] Another aspect of the present invention provides a method for cleaning a metal surface using the system described in any embodiment of the present invention, the method comprising: fixing a workpiece to be cleaned in a cleaning tank, providing a cleaning medium in a liquid preparation tank, and activating a plasma generator, an ultrasonic generator, and optionally a micro / nano bubble generator to clean the workpiece.

[0017] In one or more embodiments, the cleaning medium does not include surfactants, emulsifiers, and defoamers.

[0018] In one or more embodiments, the cleaning medium is an alkaline solution, an acidic solution, or a neutral salt solution.

[0019] In one or more embodiments, the alkaline solution has a mass fraction of 4%-15%, and the solute in the alkaline solution is preferably selected from one or more of sodium hydroxide, sodium carbonate, and trisodium phosphate.

[0020] In one or more embodiments, the acid solution has a mass fraction of 3%-10%, and the solute in the acid solution is preferably selected from one or more of hydrochloric acid, sulfuric acid, and citric acid.

[0021] In one or more embodiments, the neutral salt solution has a mass fraction of 4%-12%, and the solute in the neutral salt solution is preferably selected from one or both of sodium sulfate and sodium nitrate.

[0022] In one or more embodiments, the temperature of the cleaning medium is 20-60°C; In one or more embodiments, the method further includes a pretreatment process, which includes dust removal and high-pressure coarse washing.

[0023] In one or more embodiments, the method further includes post-processing, which includes pure water spraying, neutralization passivation, and low-temperature drying.

[0024] In one or more embodiments, the cleaning medium is an alkaline solution, wherein the solute in the alkaline solution is selected from one or more of sodium hydroxide, sodium carbonate, and trisodium phosphate; the mass fraction of the alkaline solution is 4%-12%; and the temperature of the cleaning medium is 30-60°C.

[0025] In one or more embodiments, the gas source for the micro / nano bubble generator is air.

[0026] In one or more embodiments, the micro / nano bubble generator produces bubbles with an average particle size of 50 nm-50 μm and a gas flow rate of 0.5-2 m³ / h. 3 / h.

[0027] In one or more embodiments, the working gas of the plasma generator is air.

[0028] In one or more embodiments, the discharge power of the plasma generator is 50-300W.

[0029] In one or more embodiments, the method further includes turning on a DC power supply, wherein the electrolysis temperature is 30-60°C and the DC voltage is 5-12V.

[0030] In one or more embodiments, the cleaning medium is an alkaline solution, wherein the solute in the alkaline solution is selected from one or more of sodium hydroxide, sodium carbonate, and trisodium phosphate; and the mass fraction of the alkaline solution is 5%-15%.

[0031] In one or more embodiments, the gas source for the micro / nano bubble generator is air.

[0032] In one or more embodiments, the micro / nano bubble generator produces bubbles with an average particle size of 50 nm-50 μm and a gas flow rate of 0.5-2 m³ / h. 3 / h.

[0033] In one or more embodiments, the working gas of the plasma generator is air.

[0034] In one or more embodiments, the discharge power of the plasma generator is 60-320W.

[0035] In one or more embodiments, the cleaning medium is an acid solution, wherein the solute in the acid solution is selected from one or more of hydrochloric acid, sulfuric acid, and citric acid; the mass fraction of the acid solution is 3%-9%; and the temperature of the cleaning medium is 25-45°C.

[0036] In one or more embodiments, the gas source for the micro / nano bubble generator is oxygen.

[0037] In one or more embodiments, the micro / nano bubble generator produces bubbles with an average particle size of 50 nm-50 μm and a gas flow rate of 0.3-1.5 m³ / s. 3 / h.

[0038] In one or more embodiments, the working gas of the plasma generator is oxygen.

[0039] In one or more embodiments, the discharge power of the plasma generator is 40-250W.

[0040] In one or more embodiments, the method further includes turning on a DC power supply, wherein the electrolysis temperature is 25-45°C and the DC voltage is 3-8V.

[0041] In one or more embodiments, the cleaning medium is an acid solution, wherein the solute in the acid solution is selected from one or more of hydrochloric acid, sulfuric acid, and citric acid; and the mass fraction of the acid solution is 3%-10%.

[0042] In one or more embodiments, the gas source for the micro / nano bubble generator is oxygen.

[0043] In one or more embodiments, the micro / nano bubble generator produces bubbles with an average particle size of 50 nm-50 μm and a gas flow rate of 0.3-1.5 m³ / s. 3 / h.

[0044] In one or more embodiments, the working gas of the plasma generator is oxygen.

[0045] In one or more embodiments, the discharge power of the plasma generator is 50-280W.

[0046] In one or more embodiments, the method further includes turning on a DC power supply, wherein the electrolysis temperature is 20-50°C and the DC voltage is 6-15V.

[0047] In one or more embodiments, the cleaning medium is a neutral salt solution, wherein the solute in the neutral salt solution is selected from one or both of sodium sulfate and sodium nitrate; and the mass fraction of the neutral salt solution is 4%-12%.

[0048] In one or more embodiments, the gas source for the micro / nano bubble generator is nitrogen.

[0049] In one or more embodiments, the micro / nano bubble generator produces bubbles with an average particle size of 50 nm-50 μm and a gas flow rate of 0.4-1.8 m³ / s. 3 / h.

[0050] In one or more embodiments, the working gas of the plasma generator is nitrogen.

[0051] In one or more embodiments, the discharge power of the plasma generator is 30-200W.

[0052] Another aspect of the present invention provides the application of the cleaning tank, the system, and the method described in any embodiment of the present invention in the industrial batch cleaning of precision parts.

[0053] In one or more embodiments, the precision component is made of carbon steel, stainless steel, or aluminum alloy.

[0054] The system of this invention covers multiple optional implementation methods and can be applied to five types of cleaning conditions: conventional alkaline washing, conventional acid washing, alkaline electrolysis, acid electrolysis, and neutral salt electrolysis. It is easy to configure according to cleaning needs, adapting to different budgets and cleanliness requirements, and significantly reducing overall energy and material consumption (for example, the total electrical energy consumption of cleaning agents and electrolysis / ultrasound can be reduced by 35%-60% compared to traditional processes). Furthermore, the system of this invention is highly versatile, requiring only the addition of corresponding equipment to existing production lines, resulting in low modification costs. Moreover, the cleaning media suitable for the system of this invention preferably does not include organic additives such as surfactants, emulsifiers, and defoamers, further reducing foam and the burden on subsequent rinsing.

[0055] The method of this invention utilizes plasma to generate active species, oxidizing and decomposing organic oil stains and softening the oxide layer; it utilizes micro-nano bubbles for forced mass transfer and cavitation effects to renew the interfacial liquid film and penetrate dead corners; and it utilizes ultrasonic cavitation to generate instantaneous high-energy microjets to precisely break up stubborn deposits. Furthermore, the method of this invention achieves a triple coupling of active species generated by a plasma generator, micro-nano bubbles, and ultrasound. Micro-nano bubbles provide nucleation sites for ultrasonic cavitation, reducing ultrasonic energy consumption and carrying active species deep into crevices, thus achieving synergistic enhancement of global mass transfer, chemical degradation, and localized high-energy impact. This further improves the cleanliness level that is difficult to achieve with traditional processes, increasing workpiece cleanliness by 15%-30% compared to schemes using only two of these devices. The forced mass transfer through micro-nano bubbles and the ultrasonic cavitation effect promotes uniform interfacial concentration, effectively inhibiting matrix over-corrosion and surface blooming caused by localized acid enrichment. The ultrasonic cavitation effect continuously strips deposits from the electrode surface, reducing electrode contamination and extending the maintenance cycle of electrodes connected to a DC power supply in the cleaning tank to form an electrolytic electric field to more than twice the original period. Attached Figure Description

[0056] Figure 1 This is a schematic diagram of the system according to some embodiments of the present invention.

[0057] The following are the annotations in the attached diagram: 1-Liquid mixing tank; 2-Circulation pump; 3-Micro-nano bubble generator; 4-Low-temperature plasma generator; 5-Ultrasonic titanium alloy vibrating plate; 6-Cleaning tank; 7-Electrode; 71-Workpiece; 72-Auxiliary electrode; 8-DC power supply; 9-Circulation filtration device; 10-Return pipeline. Detailed Implementation

[0058] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used herein are explained and defined in general terms below. Unless otherwise specified, all technical and scientific terms used herein have the common meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0059] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0060] In this document, the terms “contains,” “includes,” “containing,” and similar terms encompass the meanings of “basically composed of” and “composed of.” For example, when this document discloses “A contains B and C,” “A is basically composed of B and C” and “A is composed of B and C” should be considered as having been disclosed in this document.

[0061] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0062] Unless otherwise specified, percentages refer to mass percentages and proportions refer to mass ratios in this article.

[0063] In this article, the sum of the percentages of all components in the composition is 100%.

[0064] In this document, when describing embodiments or examples, it should be understood that it is not intended to limit the invention to those embodiments or examples. Rather, all alternatives, modifications, and equivalents of the methods and materials described herein are covered within the scope of this invention.

[0065] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0066] The cleaning tank for cleaning metal surfaces according to the present invention includes: The tank is used to hold the workpiece to be cleaned. A plasma generator, installed on the side wall of the tank, for introducing active species into the cleaning medium within the tank; and An ultrasonic generator is installed on the side wall and / or bottom of the tank.

[0067] In some implementations, the plasma generating device is a cryogenic plasma generating device. In this document, a cryogenic plasma generating device refers to a device that inputs energy into the working gas through an electric field, radio frequency, microwave, or other energy forms, causing the working gas to ionize, excite, and / or dissociate, thereby forming a non-thermal plasma and generating one or more active species. The cryogenic plasma is a non-thermal plasma, in which electrons have high energy while the overall temperature of the gas components is relatively low.

[0068] In some embodiments, the working gas of the plasma generator is air, oxygen, or nitrogen; the working gas is excited by plasma to generate one or more active species, including one or more of free radicals, atoms, excited-state molecules, ions, and ozone.

[0069] In some implementations, the discharge power of the plasma generator is 30-320W, for example, 30W, 40W, 50W, 60W, 80W, 100W, 120W, 140W, 150W, 160W, 180W, 200W, 220W, 240W, 250W, 260W, 280W, 300W, 320W, or any range between two values. Controlling the discharge power within this range helps ensure that the amount of active species generated meets the cleaning requirements, while avoiding increased energy consumption and electrode wear due to excessive power. In this invention, the plasma generator is located inside the side wall of the cleaning tank, which facilitates shortening the transport path of the active species. The generated active species come into contact with the cleaning medium through a gas-liquid contact unit (e.g., a microporous aerator), and are uniformly diffused to the workpiece surface with the circulating cleaning medium, which is beneficial for achieving full-area mass transfer and improving gas-liquid contact efficiency.

[0070] In this invention, the ultrasonic generator is preferably made of corrosion-resistant titanium alloy, such as an ultrasonic titanium alloy vibrating plate. In some embodiments, the ultrasonic generator is an ultrasonic titanium alloy vibrating plate, which is placed on the side wall and / or bottom of the cleaning tank. This improves the ultrasonic energy transmission efficiency and is resistant to acid and alkali corrosion, making it suitable for various cleaning conditions. In some embodiments, the ultrasonic frequency of the ultrasonic titanium alloy vibrating plate is 20-40kHz, such as 20kHz, 22kHz, 24kHz, 26kHz, 28kHz, 30kHz, 32kHz, 34kHz, 35kHz, 36kHz, 38kHz, 40kHz, or any range between two values. The ultrasonic power density of the titanium alloy ultrasonic transducer plate is 10-30 W / L, for example, 10 W / L, 12 W / L, 14 W / L, 15 W / L, 16 W / L, 18 W / L, 20 W / L, 22 W / L, 24 W / L, 25 W / L, 26 W / L, 28 W / L, 30 W / L, or any range between two values. Controlling the ultrasonic frequency and power density within this range is beneficial for generating a stable cavitation effect in the cleaning medium, while also meeting the cleaning needs of workpieces made of different materials, balancing cleaning effectiveness with substrate protection.

[0071] The system for cleaning metal surfaces of the present invention includes: A mixing tank is used to store cleaning media; A circulating pump is used to transport the cleaning medium from the liquid preparation tank to the micro / nano bubble generator; Micro / nano bubble generator, used to generate micro / nano bubbles; The cleaning tank described in any embodiment of the present invention is used to fix the workpiece to be cleaned; A circulating filter device is used to receive the cleaning medium carrying stripped contaminants flowing out of the cleaning tank and remove the scum therein; The return pipeline is used to return the cleaning medium filtered by the circulating filter to the liquid preparation tank, so that the cleaning medium is in a state of circulation. The liquid preparation tank, circulating pump, micro-nano bubble generator, cleaning tank, circulating filter device and return pipeline are connected in sequence to form a cleaning medium circulation loop. A DC power supply and electrodes, wherein the electrodes include a workpiece to be cleaned and an auxiliary electrode; the DC power supply and the electrodes are connected to form an electrolytic circuit.

[0072] In some implementations, the system also includes a plasma generator located in the return line.

[0073] In this invention, the gas source for the micro / nano bubble generator is air, oxygen, or nitrogen. The gas source is matched according to the acid-base properties of the cleaning medium: air for alkaline media, oxygen for acidic media, and nitrogen for neutral precision cleaning. This facilitates achieving optimal cleaning results and avoiding adverse reactions under each working condition. In some embodiments, the micro / nano bubbles are generated using a media circulation generator, with the bubbles remaining in the liquid phase for at least 30 minutes, which is beneficial for the bubbles to fully adhere to the workpiece surface and crevices and exert their effect. In this invention, the media circulation generator utilizes a circulating pump to pass the cleaning medium through a Venturi mixer or gas-liquid mixing chamber, forming micro / nano-scale bubbles under negative pressure suction, shearing, and dissolved gas release, and continuously returning the bubble-containing cleaning medium to the cleaning tank. In some embodiments, the micro / nano bubble generator is a Venturi-type micro / nano bubble generator.

[0074] In this invention, the average particle size of the bubbles generated by the micro / nano bubble generator is 50 nm to 50 μm, for example, 50 nm, 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, 1 μm, 2 μm, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, or any range between two values. Controlling the average particle size of the micro / nano bubbles within the above range is beneficial for the bubbles to maintain sufficient retention time and gas-liquid interface area in the liquid phase, thereby enhancing interfacial mass transfer and permeation effects.

[0075] In this invention, the gas phase flow rate of the micro / nano bubble generator is 0.3-2 m³ / s. 3 / h, for example 0.3m 3 / h, 0.4m 3 / h, 0.5m 3 / h, 0.6m 3 / h, 0.7m 3 / h, 0.8m 3 / h, 0.9m 3 / h、1m 3 / h, 1.1m 3 / h, 1.2m 3 / h, 1.3m 3 / h, 1.4m 3 / h, 1.5m 3 / h, 1.6m 3 / h, 1.7m 3 / h, 1.8m 3 / h, 1.9m 3 / h、2m 3 / h or any range between two values. Controlling the gas flow rate within the above range helps ensure the bubble generation density per unit volume of cleaning medium, while avoiding temperature drop and increased energy consumption of the cleaning medium due to excessive flow rate.

[0076] In this invention, the DC voltage of the DC power supply is 3-15V, such as 3V, 4V, 5V, 6V, 7V, 8V, 9V, 10V, 11V, 12V, 13V, 14V, 15V, or any range between two values.

[0077] In some embodiments, the system of the present invention is as follows: Figure 1 As shown, the system includes a liquid preparation tank (1), a circulation pump (2), a micro / nano bubble generator (3), a low-temperature plasma generator (4), an ultrasonic titanium alloy vibrating plate (5), a cleaning tank (6), electrodes (7) (including workpiece (71); auxiliary electrode (72)), a DC power supply (8), a circulation filter (9), and a return pipeline (10). Its working process includes: the liquid preparation tank (1) prepares the cleaning medium; the circulation pump (2) sends the cleaning medium into the micro / nano bubble generator (3), generating micro / nano bubbles and injecting them into the cleaning tank (6); the low-temperature plasma generator (4) introduces active species into the circulating cleaning medium through its internal gas-liquid contact unit; the ultrasonic titanium alloy vibrating plate (5) synchronously generates ultrasonic waves; and the DC power supply (8) is connected under electrolysis conditions. The plasma field, micro / nano bubble field, ultrasonic cavitation field, and electric field work together to clean the medium. After removing scum through the circulation filter (9), the cleaning medium returns through the return pipeline (10), achieving continuous and stable cleaning.

[0078] The method for cleaning metal surfaces according to the present invention includes: fixing the workpiece to be cleaned in a cleaning tank using the system described in any embodiment of the present invention, providing a cleaning medium in a liquid preparation tank, and turning on a plasma generator, an ultrasonic generator, and optionally a micro / nano bubble generator to clean the workpiece.

[0079] In some embodiments, the method of the present invention further includes a pretreatment process, which includes dust removal and high-pressure rough cleaning. The high-pressure rough cleaning refers to a pre-cleaning step in which the workpiece surface is sprayed with water or a cleaning medium at 0.3-0.8 MPa before entering the fine cleaning tank to remove loose dust, scum, and large particulate contaminants.

[0080] In some embodiments, the method of the present invention further includes a post-treatment process, which includes pure water spraying, neutralization passivation, and low-temperature drying. In some preferred embodiments, the post-treatment includes multiple pure water spraying processes. The low-temperature drying temperature is preferably 50-80°C, for example, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, or any range between two values, preferably 60°C, until no visible water film remains on the workpiece surface.

[0081] In some preferred embodiments, the cleaning medium does not include surfactants, emulsifiers, and defoamers. By not adding any organic additives to the cleaning medium, it is beneficial to reduce foam generation during the cleaning process, reduce the burden on subsequent rinsing, and avoid interference from organic additives on plasma discharge characteristics.

[0082] In this invention, the cleaning medium can be an alkaline solution, an acidic solution, or a neutral salt solution, depending on the specific cleaning process requirements. The cleaning can be performed using a flowing rinse method, an immersion method, or a combination of both. In some embodiments, when using a flowing rinse method, the cleaning medium flows over the surface of the workpiece to be cleaned in a flowing state, with a flow rate of 1.0 m / s to 1.5 m / s. In some embodiments, when using an immersion method, the workpiece to be cleaned is submerged in the cleaning medium, which is either stationary or in a low-speed circulating state. In some embodiments, a combination of immersion and flowing rinse is used.

[0083] When the cleaning medium is an alkaline solution, the solute in the alkaline solution is preferably selected from one or more of sodium hydroxide, sodium carbonate, and trisodium phosphate; the mass fraction of the alkaline solution is 4%-15%, for example, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 11%, 11.5%, 12%, 12.5%, 13%, 13.5%, 14%, 14.5%, 15%, or any range between two values. Controlling the mass fraction of the alkaline solution within the above range helps to reduce the consumption of alkaline agents and reduce the risk of substrate corrosion while ensuring the saponification and emulsification degreasing effects. In some preferred embodiments, the solute in the alkaline solution is selected from sodium hydroxide and sodium carbonate, and the mass ratio of sodium hydroxide to sodium carbonate is 1:1-3:1, preferably 2:1.

[0084] When the cleaning medium is an acid solution, the solute in the acid solution is selected from one or more of hydrochloric acid, sulfuric acid, and citric acid; the mass fraction of the acid solution is 3%-10%, for example, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, or any range between two values. Controlling the mass fraction of the acid solution within the above range is beneficial for inhibiting over-corrosion of the substrate while ensuring the rust and oxide scale removal effect. In some preferred embodiments, the solute in the acid solution is selected from citric acid and sulfuric acid, and the mass ratio of citric acid to sulfuric acid is 1:1-3:1, preferably 2:1, wherein the source of the sulfuric acid as a solute can be dilute sulfuric acid with a mass fraction of 5%-10%.

[0085] When the cleaning medium is a neutral salt solution, the solute in the neutral salt solution is selected from one or both of sodium sulfate and sodium nitrate; the mass fraction of the neutral salt solution is 4%-12%, for example, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 11%, 11.5%, 12%, or any range between two values. Controlling the mass fraction of the neutral salt solution within the above range helps to ensure electrolytic conductivity while reducing the risk of salt crystallization, making it suitable for non-destructive cleaning of highly reactive and easily corroded workpieces such as aluminum alloys.

[0086] In the system of this invention, the cleaning temperature (i.e., the temperature of the cleaning medium) during the cleaning of metal surfaces is 20-60℃, for example, 20℃, 22℃, 24℃, 26℃, 28℃, 30℃, 32℃, 34℃, 36℃, 38℃, 40℃, 42℃, 44℃, 46℃, 48℃, 50℃, 52℃, 54℃, 56℃, 58℃, 60℃, or any range between two values. Controlling the temperature of the cleaning medium within the above range is beneficial for promoting the chemical reaction rate and improving the activity of the cleaning medium, while avoiding increased energy consumption and the risk of workpiece thermal deformation caused by excessively high temperatures.

[0087] In the method of the present invention, the average particle size of the bubbles generated by the micro-nano bubble generator is preferably 50nm-50μm, the ultrasonic frequency of the ultrasonic generator is preferably 20-40kHz, and the ultrasonic power density of the ultrasonic generator is preferably 10-30W / L.

[0088] Furthermore, for different cleaning conditions, the parameters in the method of this invention are set as follows: In conventional alkaline washing processes, a DC power supply is not activated. The cleaning medium is an alkaline solution with a mass fraction of 4%-12%, for example, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 11%, 11.5%, 12%, or any range of two values. The temperature of the cleaning medium is 30-60℃, for example, 30℃, 32℃, 34℃, 36℃, 38℃, 40℃, 42℃, 44℃, 46℃, 48℃, 50℃, 52℃, 54℃, 56℃, 58℃, 60℃, or any range of two values. The gas source for the micro / nano bubble generator is air, with a gas flow rate of 0.5-2 m³ / h. 3 / h, for example 0.5m 3 / h, 0.6m 3 / h, 0.7m 3 / h, 0.8m 3 / h, 0.9m 3 / h、1m3 / h, 1.1m 3 / h, 1.2m 3 / h, 1.3m 3 / h, 1.4m 3 / h, 1.5m 3 / h, 1.6m 3 / h, 1.7m 3 / h, 1.8m 3 / h, 1.9m 3 / h、2m 3 / h or any range between two values. The working gas of the plasma generator is air, and the discharge power is 50-300W, for example, 50W, 60W, 80W, 100W, 120W, 140W, 150W, 160W, 180W, 200W, 220W, 240W, 250W, 260W, 280W, 300W or any range between two values.

[0089] In the alkaline electrolysis process, the DC power supply is turned on, and the electrolysis temperature (i.e., the temperature of the cleaning medium (electrolyte) under electrolysis conditions) is 30-60℃, for example, 30℃, 32℃, 34℃, 36℃, 38℃, 40℃, 42℃, 44℃, 46℃, 48℃, 50℃, 52℃, 54℃, 56℃, 58℃, 60℃, or any range between two values. The DC voltage is 5-12V, for example, 5V, 6V, 7V, 8V, 9V, 10V, 11V, 12V, or any range between two values. The cleaning medium is an alkaline solution with a mass fraction of 5%-15%, for example, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 11%, 11.5%, 12%, 12.5%, 13%, 13.5%, 14%, 14.5%, 15%, or any range between two values. The gas source for the micro / nano bubble generator is air, with a gas flow rate of 0.5-2 m³ / h. 3 / h, for example 0.5m 3 / h, 0.6m 3 / h, 0.7m 3 / h, 0.8m 3 / h, 0.9m 3 / h、1m 3 / h, 1.1m 3 / h, 1.2m 3 / h, 1.3m 3 / h, 1.4m 3 / h, 1.5m 3 / h, 1.6m 3 / h, 1.7m 3 / h, 1.8m 3 / h, 1.9m 3 / h、2m 3 / h or any range between two values. The working gas of the plasma generator is air, and the discharge power is 60-320W, for example, 60W, 80W, 100W, 120W, 140W, 150W, 160W, 180W, 200W, 220W, 240W, 250W, 260W, 280W, 300W, 320W or any range between two values. During electrolytic cleaning, the micro-nano bubbles distributed in the electrolyte serve as ultrasonic cavitation nucleation sites, which can increase the cavitation bubble generation density, reduce the operating energy consumption of the ultrasonic device, and further synergistically enhance the cleaning effect. The alkaline electrolysis process of this invention can eliminate ion concentration stratification. Compared with the blank control process that uses only DC electrolysis without turning on the micro-nano bubbles, plasma generator, and ultrasonic generator under the same workpiece, alkaline concentration, temperature, and final cleanliness conditions, its cleaning efficiency is increased by more than 60%, alkaline consumption is reduced by more than 40%, and power consumption is reduced by more than 45%.

[0090] In conventional pickling processes, a DC power supply is not activated. The cleaning medium is an acid solution with a mass fraction of 3%-9%, for example, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, or any range of two values. The temperature of the cleaning medium is 25-45℃, for example, 25℃, 27℃, 29℃, 30℃, 31℃, 33℃, 35℃, 37℃, 39℃, 41℃, 43℃, 45℃, or any range of two values. The gas source for the micro / nano bubble generator is oxygen, with a gas flow rate of 0.3-1.5 m³ / s. 3 / h, for example 0.3m 3 / h, 0.4m 3 / h, 0.5m 3 / h, 0.6m 3 / h, 0.7m 3 / h, 0.8m 3 / h, 0.9m 3 / h、1m 3 / h, 1.1m 3 / h, 1.2m 3 / h, 1.3m 3 / h, 1.4m 3 / h, 1.5m 3 / h or any range between two values. The working gas of the plasma generator is oxygen, and the discharge power is 40-250W, for example 40W, 50W, 60W, 80W, 100W, 120W, 140W, 150W, 160W, 180W, 200W, 220W, 240W, 250W or any range between two values.

[0091] In the acid electrolysis process, a DC power supply is turned on. The electrolysis temperature is 25-45℃, for example, 25℃, 27℃, 29℃, 30℃, 31℃, 33℃, 35℃, 37℃, 39℃, 41℃, 43℃, 45℃, or any combination of two values. The DC voltage is 3-8V, for example, 3V, 4V, 5V, 6V, 7V, 8V, or any combination of two values. The cleaning medium is an acid solution with a mass fraction of 3%-10%, for example, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, or any combination of two values. The gas source for the micro / nano bubble generator is oxygen, with a gas flow rate of 0.3-1.5 m³ / s. 3 / h, for example 0.3m 3 / h, 0.4m 3 / h, 0.5m 3 / h, 0.6m 3 / h, 0.7m 3 / h, 0.8m 3 / h, 0.9m 3 / h、1m 3 / h, 1.1m 3 / h, 1.2m 3 / h, 1.3m 3 / h, 1.4m 3 / h, 1.5m 3 / h or any range between two values. The working gas of the plasma generator is oxygen, and the discharge power is 50-280W, for example 50W, 60W, 80W, 100W, 120W, 140W, 150W, 160W, 180W, 200W, 220W, 240W, 250W, 260W, 280W or any range between two values. The acid electrolysis process of this invention can effectively suppress local over-corrosion, and its cleaning time is shortened by 45%-60% compared with the blank control process that uses only DC electrolysis without turning on the micro-nano bubbles, plasma generator and ultrasonic generator under the same workpiece, acid concentration, temperature and final cleanliness conditions.

[0092] In the neutral salt electrolysis process, a DC power supply is turned on. The electrolysis temperature is 20-50℃, for example, 20℃, 22℃, 24℃, 26℃, 28℃, 30℃, 32℃, 34℃, 36℃, 38℃, 40℃, 42℃, 44℃, 46℃, 48℃, 50℃, or any combination of two values. The DC voltage is 6-15V, for example, 6V, 7V, 8V, 9V, 10V, 11V, 12V, 13V, 14V, 15V, or any combination of two values. The cleaning medium is a neutral salt solution with a mass fraction of 4%-12%, for example, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 11%, 11.5%, 12%, or any combination of two values. The gas source for the micro / nano bubble generator is nitrogen, with a gas flow rate of 0.4-1.8 m³ / s. 3 / h, for example 0.4m 3 / h, 0.5m 3 / h, 0.6m 3 / h, 0.7m 3 / h, 0.8m 3 / h, 0.9m 3 / h、1m 3 / h, 1.1m 3 / h, 1.2m 3 / h, 1.3m 3 / h, 1.4m 3 / h, 1.5m 3 / h, 1.6m 3 / h, 1.7m 3 / h, 1.8m 3 / h or any range between two values. The working gas of the plasma generator is nitrogen, and the discharge power is 30-200W, for example, 30W, 40W, 50W, 60W, 80W, 100W, 120W, 140W, 150W, 160W, 180W, 200W, or any range between two values. Using nitrogen as the working gas and avoiding the use of chlorine-containing electrolytes helps reduce the risk of corrosion caused by strong oxidizing byproducts and chlorine evolution, making it suitable for non-destructive precision electrolytic cleaning of highly reactive and easily corroded workpieces such as aluminum alloys and electronic precision components.

[0093] The conventional alkaline washing process, electrolytic alkaline washing process, conventional acid washing process, acid electrolysis process, and neutral salt electrolysis process of the present invention can significantly improve cleanliness, shorten cleaning time, achieve no pollutant residue, no surface discoloration and substrate corrosion defects, while reducing reagent and overall energy consumption, and are suitable for static immersion and continuous electrolysis industrial production lines.

[0094] The liquid preparation tank, circulating pump, micro / nano bubble generator, plasma generator, ultrasonic generator, cleaning tank, DC power supply, and circulating filter device applicable to this invention are all common in the art and can be purchased commercially.

[0095] In this invention, under electrolysis conditions, a DC power supply is connected to the electrodes to form an electrolysis circuit. The electrolysis electric field is coupled and synergistically enhanced by the micro / nano bubble field, plasma field, and ultrasonic cavitation field, thereby strengthening the electrochemical reaction and the removal of contaminants. Ultrasonic cavitation removes passivation precursors from the electrode surface in real time, while micro / nano bubbles promote the renewal of the electrolyte film on the workpiece surface, reducing ion concentration stratification and uneven local reactions.

[0096] In this invention, under the triple coupling mode, micro-nano bubbles serve as nucleation sites for ultrasonic cavitation, increasing the density of cavitation bubbles and reducing the energy consumption of the ultrasonic device; ultrasonic waves provide targeted high-energy impacts to break up stubborn deposits; plasma oxidizes and decomposes macromolecular pollutants; micro-nano bubbles carry active species to penetrate the gaps in the workpiece, forming a synergistic effect of global mass transfer, chemical degradation, and local high-energy impact.

[0097] In this invention, the system and method are applicable to the industrial-scale batch cleaning of precision parts such as carbon steel, stainless steel, and aluminum alloy.

[0098] The present invention will be described below by way of specific embodiments. It should be understood that these embodiments are merely illustrative and are not intended to limit the scope of the invention. The methods, reagents, and materials used in the embodiments and comparative examples are conventional methods, reagents, and materials in the art, unless otherwise stated. The starting material compounds in the embodiments and comparative examples are all commercially available.

[0099] Equipment Example 1

[0100] This device example provides a system for cleaning metal surfaces. For instance... Figure 1As shown, the system includes: a liquid preparation tank (1), a circulating pump (2), a micro / nano bubble generator (3), a low-temperature plasma generator (4), an ultrasonic titanium alloy vibrating plate (5), a cleaning tank (6), electrodes (7) (workpiece to be cleaned (71); auxiliary electrode (72)), a DC power supply (8), a circulating filter (9), and a return pipeline (10). The liquid preparation tank (1), circulating pump (2), micro / nano bubble generator (3), cleaning tank (6), circulating filter (9), and return pipeline (10) are connected to form a cleaning medium circulation loop. The low-temperature plasma generator (4) is located on the side wall of the cleaning tank (6) and introduces active species into the cleaning medium in the circulation loop through a gas-liquid contact unit (a microporous aeration head with a pore size of 20-50μm). The ultrasonic titanium alloy vibrating plate (5) is located at the bottom of the cleaning tank (6). The DC power supply (8) is connected to the electrode (7) to form an electrolysis loop. The ultrasonic titanium alloy vibrating plate consists of two 300 mm × 200 mm × 50 mm titanium alloy vibrating plates, and the distance between the workpiece to be cleaned and the ultrasonic titanium alloy vibrating plate is 100 mm.

[0101] Its working process includes: preparing the cleaning medium in the liquid preparation tank (1), sending the cleaning medium into the micro-nano bubble generator (3) by the circulation pump (2), generating micro-nano bubbles and injecting them into the cleaning tank (6); introducing active species into the circulating cleaning medium through the gas-liquid contact unit inside the low-temperature plasma generator (4); generating ultrasonic waves synchronously by the ultrasonic titanium alloy vibrating plate (5); and connecting the DC power supply (8) under electrolysis conditions. The plasma field, micro-nano bubble field, ultrasonic cavitation field and electric field work together to clean the medium. After removing the scum through the circulation filter device (9), the cleaning medium is returned through the return pipeline (10) to achieve continuous and stable cleaning.

[0102] In this invention, the amount of oil contamination is determined using a solvent extraction-gravimetric method. Oil contamination on a specified area of ​​the workpiece surface is extracted with petroleum ether, the solvent is evaporated, and the sample is weighed using an analytical balance with a graduation of 0.1 mg. The amount is calculated as oil contamination mass / sampled area, with units of mg / m². 2 The limit of detection is 10 mg / m³. 2 .

[0103] In this invention, the oxide scale coverage is determined by microscopic image area analysis, with a detection limit of 1%.

[0104] Example 1: Conventional alkaline washing

[0105] The workpiece used in this embodiment is a Q235 carbon steel mechanical test piece with threaded holes (size 100 mm × 50 mm × 5 mm, surface roughness Ra 3.2 μm), whose surface is covered with a mixture of cured machine oil and grease (2.00 ± 0.10 g / m). 2After dust removal, high-pressure rough washing and drying, carbon steel mechanical parts are placed in the cleaning tank for fixation. The solution tank (1) contains a sodium hydroxide and sodium carbonate composite alkaline solution with a mass fraction of 8% (the mass ratio of sodium hydroxide to sodium carbonate is 2:1) as the cleaning medium. The temperature of the cleaning medium is 45℃ and the flow rate of the cleaning medium is 1.5 m / s.

[0106] Normal mode (blank control group): The circulating pump (2) sends the cleaning medium from the liquid preparation tank (1) into the cleaning tank (6). The cleaning medium carrying the stripped oil flows out of the cleaning tank (6), and after the scum is removed by the circulating filter device (9), it returns to the liquid preparation tank (1) through the return pipeline (10), so that the cleaning medium is in a circulating state. The carbon steel mechanical parts fixed in the cleaning tank are completely immersed in the cleaning medium and soaked for 10 minutes.

[0107] Mode 1: The circulating pump (2) sends the cleaning medium from the liquid preparation tank (1) into the micro-nano bubble generator (3). The micro-nano bubble generator (3) uses air as the gas source to generate micro-nano bubbles with an average particle size of 10-30μm and a gas flow rate of 1.2m. 3 / h, the bubbles are injected into the cleaning tank (6) along with the cleaning medium and work together on the carbon steel mechanical parts fixed in the cleaning tank. The cleaning medium carrying the stripped oil flows out of the cleaning tank (6), and after the scum is removed by the circulating filter device (9), it returns to the liquid preparation tank (1) through the return pipeline (10), so that the cleaning medium is in a circulating state. The carbon steel mechanical parts fixed in the cleaning tank are completely immersed in the cleaning medium and soaked for 10 minutes.

[0108] Mode 2: The circulating pump (2) sends the cleaning medium from the mixing tank (1) into the cleaning tank (6). The low-temperature plasma generator (4) located on the side wall of the cleaning tank (6) (using air as the working gas and a discharge power of 150W) generates ·O, O3, ·OH and a small amount of excited nitrogen-containing active species. The above active species come into contact with the cleaning medium through the microporous aeration head and dissolve in the cleaning medium, working together to act on the carbon steel mechanical parts fixed in the cleaning tank. The cleaning medium carrying the stripped oil flows out of the cleaning tank (6), and after the floating scum is removed by the circulating filter device (9), it returns to the mixing tank (1) through the return pipeline (10), so that the cleaning medium is in a circulating state. The carbon steel mechanical parts fixed in the cleaning tank are completely immersed in the cleaning medium and soaked for 10 minutes.

[0109] Mode 3: Simultaneously activate the micro-nano bubble generator and the low-temperature plasma generator.

[0110] The circulating pump (2) delivers the cleaning medium from the liquid preparation tank (1) into the micro-nano bubble generator (3). The micro-nano bubble generator (3) uses air as the gas source to generate micro-nano bubbles with an average particle size of 10-30 μm and a gas flow rate of 1.2 m³ / s. 3 / h, bubbles are injected into the cleaning tank (6) along with the cleaning medium; the low-temperature plasma generator (4) located on the side wall of the cleaning tank (6) (using air as the working gas, with a discharge power of 150W) generates ·O, O3, ·OH and a small amount of excited nitrogen-containing active species. The above active species come into contact with the cleaning medium through the microporous aeration head and dissolve in the cleaning medium. The micro-nano bubbles, the cleaning medium and the above active species work together on the carbon steel mechanical parts fixed in the cleaning tank. The cleaning medium carrying the stripped oil flows out of the cleaning tank (6), and after the scum is removed by the circulation filter device (9), it returns to the liquid preparation tank (1) through the return pipeline (10), so that the cleaning medium is in a circulating flow state. The carbon steel mechanical parts fixed in the cleaning tank are completely immersed in the cleaning medium and soaked for 10 minutes.

[0111] Mode 4: Based on Mode 3, turn on the ultrasonic titanium alloy vibrating plate (5) located at the bottom of the cleaning tank (6) (ultrasonic frequency 28kHz, ultrasonic power density 20W / L, continuous working mode), and the carbon steel mechanical parts fixed in the cleaning tank are completely immersed in the cleaning medium and soaked for 10 minutes.

[0112] The results showed that the initial oil spillage in each mode was 2.00 g / m³. 2 The residual oil levels in the normal mode, mode 1, mode 2, mode 3, and mode 4 after treatment were 0.80 g / m³, respectively. 2 0.48 g / m 2 0.53 g / m 2 0.46 g / m 2 and <0.01 g / m 2 The absolute removal rates were 60%, 76%, 73.5%, 77%, and >99.5%, respectively; the residual amount reduction of Mode 1, Mode 2, Mode 3, and Mode 4 compared to the ordinary mode was 40%, 34%, 43%, and >98.8%, respectively. The blank control group showed significant residual oil in the crevices, requiring the cleaning medium's mass fraction to be increased to 13% for complete removal; Mode 1 showed a significant reduction in oil, with a small amount of solidified oil film remaining; Mode 2 showed surface grease decomposition, with residue remaining in thread dead corners; Mode 3 showed basic removal of internal and external oil; and Mode 4 showed surface, thread, and micropore oil levels below the detection limit of the employed detection method, with no visible residue detected. All achieved the same endpoint of cleanliness (<10 mg / m³). 2 When the mass fraction of the cleaning medium used in Mode 3 can be reduced to 5%, the mass fraction of the cleaning medium used in Mode 4 can be reduced to 4%.

[0113] Example 2: Conventional pickling

[0114] The workpiece used in this embodiment is a 304 stainless steel stamped specimen (dimensions 100 mm × 50 mm × 2 mm, surface roughness Ra 1.6 μm), whose surface has a dense oxide scale from heat treatment and rust spots (initial oxide scale coverage 95% ± 2%, oxide scale mass per unit area 120 ± 8 mg / m²). 2 After the stainless steel stamping parts are dust-removed, high-pressure rough-washed, and dried, they are placed in the cleaning tank and fixed.

[0115] The mixing tank (1) contains a 6% citric acid and sulfuric acid composite acid solution (the effective component mass ratio of citric acid and sulfuric acid is 2:1, and the sulfuric acid is added in the form of 8% dilute sulfuric acid) as the cleaning medium. The temperature of the cleaning medium is 35℃ and the flow rate of the cleaning medium is 1.2 m / s.

[0116] Normal mode (blank control group): The circulating pump (2) sends the cleaning medium from the liquid preparation tank (1) into the cleaning tank (6). The cleaning medium carrying the peeled oxide scale flows out of the cleaning tank (6), and after the scum is removed by the circulating filter device (9), it returns to the liquid preparation tank (1) through the return pipeline (10), so that the cleaning medium is in a circulating state. The stainless steel stamping parts fixed in the cleaning tank are completely immersed in the cleaning medium and soaked for 9 minutes.

[0117] Mode 1: The circulating pump (2) sends the cleaning medium from the liquid preparation tank (1) into the micro-nano bubble generator (3). The micro-nano bubble generator (3) uses oxygen as the gas source to generate micro-nano bubbles with an average particle size of 20-40μm and a gas phase flow rate of 0.8m³ / min. 3 / h, the bubbles are injected into the cleaning tank (6) along with the cleaning medium and work together on the stainless steel stamping parts fixed in the cleaning tank. The cleaning medium carrying the peeled oxide scale flows out of the cleaning tank (6), and after the scum is removed by the circulating filter device (9), it returns to the liquid preparation tank (1) through the return pipeline (10), so that the cleaning medium is in a circulating state. The stainless steel stamping parts fixed in the cleaning tank are completely immersed in the cleaning medium and soaked for 9 minutes.

[0118] Mode 2: The circulating pump (2) sends the cleaning medium from the mixing tank (1) into the cleaning tank (6). The low-temperature plasma generator (4) located on the side wall of the cleaning tank (6) (using oxygen as the working gas, with a discharge power of 120W) generates active species such as ·O, O3, and ·OH. These active species come into contact with the cleaning medium through the microporous aeration head and dissolve in the cleaning medium, working together to act on the stainless steel stamping parts fixed in the cleaning tank. The cleaning medium carrying the peeled oxide scale flows out of the cleaning tank (6), and after the scum is removed by the circulating filter device (9), it returns to the mixing tank (1) through the return pipeline (10), so that the cleaning medium is in a circulating state. The stainless steel stamping parts fixed in the cleaning tank are completely immersed in the cleaning medium and soaked for 9 minutes.

[0119] Mode 3: Simultaneously activate the micro / nano bubble generator and the low-temperature plasma generator. The circulating pump (2) delivers the cleaning medium from the liquid preparation tank (1) into the micro / nano bubble generator (3). The micro / nano bubble generator (3) uses oxygen as a gas source to generate micro / nano bubbles with an average particle size of 20-40 μm and a gas flow rate of 0.8 m³ / s. 3 / h, bubbles are injected into the cleaning tank (6) along with the cleaning medium; the low-temperature plasma generator (4) located on the side wall of the cleaning tank (6) (using oxygen as the working gas, with a discharge power of 120W) generates active species such as ·O, O3, and ·OH. The above active species come into contact with the cleaning medium through the microporous aeration head and dissolve in the cleaning medium. The micro-nano bubbles, the cleaning medium, and the above active species work together on the stainless steel stamping parts fixed in the cleaning tank. The cleaning medium carrying the oxide scale flows out of the cleaning tank (6), and after the scum is removed by the circulating filter device (9), it returns to the liquid preparation tank (1) through the return pipeline (10), so that the cleaning medium is in a circulating state. The stainless steel stamping parts fixed in the cleaning tank are completely immersed in the cleaning medium and soaked for 9 minutes.

[0120] Mode 4: Based on Mode 3, turn on the ultrasonic titanium alloy vibrating plate (5) located at the bottom of the cleaning tank (6) (ultrasonic frequency 30kHz, ultrasonic power density 15W / L, continuous working mode), and the stainless steel stamping parts fixed in the cleaning tank are completely immersed in the cleaning medium and soaked for 9 minutes.

[0121] The results showed that the initial oxide scale coverage of each group was approximately 95%. After treatment, the residual oxide scale coverage of the ordinary mode, mode 1, mode 2, mode 3, and mode 4 were 78%, 42%, 47%, 8%, and <1%, respectively, corresponding to descaling rates of approximately 17.9%, 55.8%, 50.5%, 91.6%, and >98.9%. The ordinary mode group had large areas of residual oxide scale; mode 1 and mode 2 groups only underwent surface descaling; most of the oxide scale in mode 3 dissolved; and in mode 4, the oxide scale was reduced to below the detection limit of the adopted detection method, with a smooth and uniform surface, and no localized over-corrosion or color difference.

[0122] Example 3: Alkali Electrolysis

[0123] The workpiece used in this embodiment is a Q235 carbon steel structural specimen (dimensions 120 mm × 60 mm × 6 mm, surface roughness Ra 3.2 μm), whose surface is covered with composite oil and dust (initial oil content 2.20 ± 0.12 g / m). 2 The dust adhesion amount was 0.50±0.05 g / m³. 2 After dust removal, high-pressure rough cleaning, and drying, the carbon steel structural components are placed in a cleaning tank and fixed.

[0124] The solution preparation tank (1) contains a sodium hydroxide and sodium carbonate composite alkaline electrolyte with a mass fraction of 8% (the mass ratio of sodium hydroxide to sodium carbonate is 2:1) as the cleaning medium. The temperature of the cleaning medium is 45℃, the electrolysis voltage is 8V, and the flow rate of the cleaning medium is 1.5 m / s.

[0125] Normal mode (blank control group): The circulating pump (2) sends the cleaning medium from the solution tank (1) into the cleaning tank (6), the DC power supply (8) is turned on to apply a DC voltage of 8V, and the carbon steel structural component fixed in the cleaning tank is used as the electrode (7). The electrolytic electric field and the cleaning medium work together on the surface of the workpiece. The cleaning medium carrying the stripped oil flows out of the cleaning tank (6), and after the floating scum is removed by the circulating filter device (9), it returns to the solution tank (1) through the return pipeline (10), so that the cleaning medium is in a circulating state. The carbon steel structural component fixed in the cleaning tank is completely immersed in the cleaning medium and electrolyzed for 8 minutes.

[0126] Mode 1: The circulating pump (2) sends the cleaning medium from the liquid preparation tank (1) into the micro-nano bubble generator (3). The micro-nano bubble generator (3) uses air as the gas source to generate micro-nano bubbles with an average particle size of 10-30 μm and a gas phase flow rate of 1.2 m³ / s. 3 / h, bubbles are injected into the cleaning tank (6) along with the cleaning medium; the DC power supply (8) is turned on to apply a DC voltage of 8V, and the carbon steel structural component fixed in the cleaning tank is used as an electrode (7). The micro-nano bubble field, the electrolytic electric field and the cleaning medium work together on the surface of the workpiece. The cleaning medium carrying the stripped oil flows out of the cleaning tank (6), and after the scum is removed by the circulation filter device (9), it returns to the liquid preparation tank (1) through the return pipeline (10), so that the cleaning medium is in a circulating flow state. The carbon steel structural component fixed in the cleaning tank is completely immersed in the cleaning medium and electrolyzed for 8 minutes.

[0127] Mode 2: The circulating pump (2) sends the cleaning medium from the liquid preparation tank (1) into the cleaning tank (6). The low-temperature plasma generator (4) located on the side wall of the cleaning tank (6) (using air as the working gas and a discharge power of 180W) generates ·O, O3, ·OH and a small amount of excited nitrogen-containing active species. The above active species come into contact with the cleaning medium through the microporous aeration head and dissolve in the cleaning medium. The DC power supply (8) is turned on to apply a DC voltage of 8V. The carbon steel structural component fixed in the cleaning tank is used as an electrode (7). The plasma field, the electrolytic electric field and the cleaning medium work together on the surface of the workpiece. The cleaning medium carrying the stripped oil flows out of the cleaning tank (6), and after the floating scum is removed by the circulating filter device (9), it returns to the liquid preparation tank (1) through the return pipeline (10), so that the cleaning medium is in a circulating state. The carbon steel structural component fixed in the cleaning tank is completely immersed in the cleaning medium and electrolyzed for 8 minutes.

[0128] Mode 3: Simultaneously activate the micro / nano bubble generator and the low-temperature plasma generator. The circulating pump (2) delivers the cleaning medium from the liquid preparation tank (1) into the micro / nano bubble generator (3). The micro / nano bubble generator (3) uses air as its gas source to generate micro / nano bubbles with an average particle size of 10-30 μm and a gas flow rate of 1.2 m³ / s. 3 / h, bubbles are injected into the cleaning tank (6) along with the cleaning medium; the low-temperature plasma generator (4) located on the side wall of the cleaning tank (6) (using air as the working gas, with a discharge power of 180W) generates ·O, O3, ·OH and a small amount of excited nitrogen-containing active species. The above active species come into contact with the cleaning medium through the microporous aeration head and dissolve in the cleaning medium; the DC power supply (8) is turned on to apply a DC voltage of 8V, and the carbon steel structural component fixed in the cleaning tank is used as an electrode (7). The micro-nano bubble field, plasma field, electrolytic electric field and cleaning medium work together on the surface of the workpiece. The cleaning medium carrying the stripped oil flows out of the cleaning tank (6), and after the scum is removed by the circulation filter device (9), it returns to the liquid preparation tank (1) through the return pipeline (10), so that the cleaning medium is in a circulating flow state. The carbon steel structural component fixed in the cleaning tank is completely immersed in the cleaning medium and electrolyzed for 8 minutes.

[0129] Mode 4: Based on Mode 3, turn on the ultrasonic titanium alloy vibrating plate (5) located at the bottom of the cleaning tank (6) (ultrasonic frequency 28kHz, ultrasonic power density 20W / L, continuous working mode), and the carbon steel structural parts fixed in the cleaning tank are completely immersed in the cleaning medium and electrolyzed for 8 minutes.

[0130] The results showed that the residual oil stains were ≤ 0.01g / m³. 2 To ensure complete removal of the endpoint, within a fixed 8-minute cleaning time, the residual oil levels in Modes 1, 2, 3, and 4 were 0.04 g / m³. 2 0.05 g / m 2 0.02 g / m 2 and <0.01 g / m 2 In normal mode, the endpoint was not reached after 8 minutes; it needs to be extended to 16 minutes to achieve ≤0.01 g / m³. 2 The endpoint was reached. The times required to reach the endpoint of complete removal for the normal mode, mode 1, mode 2, mode 3, and mode 4 were 16 minutes, 12 minutes, 13 minutes, 9 minutes, and 8 minutes, respectively, with energy consumption per unit workpiece of 0.40 kWh, 0.31 kWh, 0.33 kWh, 0.25 kWh, and 0.22 kWh, respectively. At the endpoint of complete removal, the amount of alkali added per unit workpiece in mode 4 decreased from 7.0 g in the blank group to 4.0 g, a 42.9% reduction in alkali consumption. The normal mode, mode 1, and mode 2 showed obvious or localized gas film coverage; mode 3 showed a significant reduction in gas film; and mode 4 showed no continuous gas film.

[0131] Example 4: Acid Electrolysis

[0132] The workpiece used in this embodiment is a 316L stainless steel precision specimen (size 100 mm × 40 mm × 2 mm, surface roughness Ra 0.8 μm), with dense oxide scale on its surface (initial oxide scale coverage 90% ± 3%, scale mass per unit area 85 ± 6 mg / m²). 2 After dust removal, high-pressure rough cleaning, and drying, the stainless steel precision structural parts are placed in a cleaning tank and fixed.

[0133] The solution preparation tank (1) is equipped with a 6% citric acid and sulfuric acid composite pickling electrolyte (the effective component mass ratio of citric acid and sulfuric acid is 2:1, and sulfuric acid is added in the form of 8% dilute sulfuric acid) as the cleaning medium. The temperature of the cleaning medium is 35℃, the electrolysis voltage is 5V, and the flow rate of the cleaning medium is 1.2m / s.

[0134] Normal mode (blank control group): The circulating pump (2) sends the cleaning medium from the solution tank (1) into the cleaning tank (6). The DC power supply (8) is turned on to apply a DC voltage of 5V. The stainless steel precision structural parts fixed in the cleaning tank are used as electrodes (7). The electrolytic electric field and the cleaning medium work together on the surface of the workpiece. The cleaning medium carrying the peeled oxide deposits flows out of the cleaning tank (6), and after the floating scum is removed by the circulating filter device (9), it returns to the solution tank (1) through the return pipeline (10), so that the cleaning medium is in a circulating state. The stainless steel precision structural parts fixed in the cleaning tank are completely immersed in the cleaning medium and electrolyzed for 6 minutes.

[0135] Mode 1: The circulating pump (2) sends the cleaning medium from the liquid preparation tank (1) into the micro-nano bubble generator (3). The micro-nano bubble generator (3) uses oxygen as the gas source to generate micro-nano bubbles with an average particle size of 20-40 μm and a gas phase flow rate of 0.8 m³ / s. 3 / h, bubbles are injected into the cleaning tank (6) along with the cleaning medium; the DC power supply (8) is turned on to apply a DC voltage of 5V, and the stainless steel precision structural parts fixed in the cleaning tank are used as electrodes (7). The micro-nano bubble field, the electrolytic electric field and the cleaning medium work together on the surface of the workpiece. The cleaning medium carrying the peeling oxide deposits flows out of the cleaning tank (6), and after the scum is removed by the circulation filter device (9), it returns to the liquid preparation tank (1) through the return pipeline (10), so that the cleaning medium is in a circulating flow state. The stainless steel precision structural parts fixed in the cleaning tank are completely immersed in the cleaning medium and electrolyzed for 6 minutes.

[0136] Mode 2: The circulating pump (2) sends the cleaning medium from the liquid preparation tank (1) into the cleaning tank (6). The low-temperature plasma generator (4) located on the side wall of the cleaning tank (6) (using oxygen as the working gas and a discharge power of 140W) generates active species such as ·O, O3, and ·OH. The above active species come into contact with the cleaning medium through the microporous aeration head and dissolve in the cleaning medium. The DC power supply (8) is turned on to apply a DC voltage of 5V. The stainless steel precision structural parts fixed in the cleaning tank are used as electrodes (7). The plasma field, electrolytic electric field and cleaning medium work together on the surface of the workpiece. The cleaning medium carrying the peeled oxide scale flows out of the cleaning tank (6), and after the floating scum is removed by the circulating filter device (9), it returns to the liquid preparation tank (1) through the return pipeline (10), so that the cleaning medium is in a circulating state. The stainless steel precision structural parts fixed in the cleaning tank are completely immersed in the cleaning medium and electrolyzed for 6 minutes.

[0137] Mode 3: Simultaneously activate the micro / nano bubble generator and the low-temperature plasma generator. The circulating pump (2) delivers the cleaning medium from the liquid preparation tank (1) into the micro / nano bubble generator (3). The micro / nano bubble generator (3) uses oxygen as a gas source to generate micro / nano bubbles with an average particle size of 20-40 μm and a gas flow rate of 0.8 m³ / s. 3 / h, bubbles are injected into the cleaning tank (6) along with the cleaning medium; the low-temperature plasma generator (4) located on the side wall of the cleaning tank (6) (using oxygen as the working gas, with a discharge power of 140W) generates active species such as ·O, O3, and ·OH. The above active species come into contact with the cleaning medium through the microporous aeration head and dissolve in the cleaning medium; the DC power supply (8) is turned on to apply a DC voltage of 5V, and the stainless steel precision structural parts fixed in the cleaning tank are used as electrodes (7). The micro-nano bubble field, plasma field, electrolytic electric field and cleaning medium work together on the surface of the workpiece. The cleaning medium carrying the peeling oxide scale flows out of the cleaning tank (6), and after the scum is removed by the circulation filter device (9), it returns to the liquid preparation tank (1) through the return pipeline (10), so that the cleaning medium is in a circulating flow state. The stainless steel precision structural parts fixed in the cleaning tank are completely immersed in the cleaning medium and electrolyzed for 6 minutes.

[0138] Mode 4: Based on Mode 3, turn on the ultrasonic titanium alloy vibrating plate (5) located at the bottom of the cleaning tank (6) (ultrasonic frequency 30kHz, ultrasonic power density 15W / L, continuous working mode), and the stainless steel precision structural parts fixed in the cleaning tank are completely immersed in the cleaning medium and electrolyzed for 6 minutes.

[0139] The results showed that, based on the residual scale mass per unit area, the residual scale masses in the ordinary mode, mode 1, mode 2, mode 3, and mode 4 were 36 mg / m², respectively. 2 24 mg / m 2 20 mg / m 2 15 mg / m2 and <1 mg / m 2 The oxide scale coverage on the electrode surface was 32%, 18%, 12%, 5%, and <1%, respectively. The standard mode group showed localized corrosion and mottled appearance; modes one through three all showed improved uniformity; in mode four, the oxide layer was reduced to below the detection limit of the employed detection method, the surface was uniform, and there was no oxide scale buildup on the electrode. Compared to the standard mode, mode four reduced the time required to reach the same detection limit endpoint from approximately 14.3 minutes to 6 minutes, improving cleaning efficiency by approximately 58%.

[0140] Example 5: Neutral Salt Electrolysis

[0141] The workpiece used in this embodiment is a 6061 aluminum alloy electronic structure test piece (size 80 mm × 40 mm × 2 mm, surface roughness Ra 0.8 μm). Its surface has trace amounts of oil, processing-induced impurities, and a thin passivation layer (initial oil content 0.30 ± 0.03 g / m). 2 Particulate impurities 15±2 mg / m 2 (Passivation layer thickness 20±3 nm). After dust removal, high-pressure rough cleaning and drying, the aluminum alloy electronic precision components are placed in the cleaning tank for fixation.

[0142] The solution preparation tank (1) is equipped with a 9% sodium sulfate neutral salt electrolyte as the cleaning medium. The temperature of the cleaning medium is 30℃, the electrolysis voltage is 10V, and the flow rate of the cleaning medium is 1 m / s.

[0143] Normal mode (blank control group): The circulating pump (2) sends the cleaning medium from the solution tank (1) into the cleaning tank (6). The DC power supply (8) is turned on to apply a DC voltage of 10V. The aluminum alloy electronic precision parts fixed in the cleaning tank are used as electrodes (7). The electrolytic electric field and the cleaning medium work together on the surface of the workpiece. The cleaning medium carrying the removed contaminants flows out of the cleaning tank (6), and after the floating scum is removed by the circulating filter device (9), it returns to the solution tank (1) through the return pipeline (10), so that the cleaning medium is in a circulating state. The aluminum alloy electronic precision parts fixed in the cleaning tank are completely immersed in the cleaning medium and electrolyzed for 7 minutes.

[0144] Mode 1: The circulating pump (2) sends the cleaning medium from the liquid preparation tank (1) into the micro-nano bubble generator (3). The micro-nano bubble generator (3) uses nitrogen as the gas source to generate micro-nano bubbles with an average particle size of 10-30 μm and a gas phase flow rate of 1.0 m³ / s. 3 / h, bubbles are injected into the cleaning tank (6) along with the cleaning medium; the DC power supply (8) is turned on to apply a DC voltage of 10V, and the aluminum alloy electronic precision parts fixed in the cleaning tank are used as electrodes (7). The micro-nano bubble field, the electrolytic electric field and the cleaning medium work together on the surface of the workpiece. The cleaning medium carrying the stripped contaminants flows out of the cleaning tank (6), and after the scum is removed by the circulation filter device (9), it returns to the liquid preparation tank (1) through the return pipeline (10), so that the cleaning medium is in a state of circulation. The aluminum alloy electronic precision parts fixed in the cleaning tank are completely immersed in the cleaning medium and electrolyzed for 7 minutes.

[0145] Mode 2: The circulating pump (2) sends the cleaning medium from the liquid preparation tank (1) into the cleaning tank (6). The low-temperature plasma generator (4) located on the side wall of the cleaning tank (6) (using nitrogen as the working gas and a discharge power of 80W) generates excited state N2 and N2. + The cleaning medium contains active species such as ·N and a small amount of ·OH generated from the aqueous phase. These active species come into contact with the cleaning medium through the microporous aeration head and dissolve in the cleaning medium. A DC power supply (8) is connected to apply a DC voltage of 10V. The aluminum alloy electronic precision parts fixed in the cleaning tank are used as electrodes (7). The plasma field, electrolytic electric field and cleaning medium work together on the surface of the workpiece. The cleaning medium carrying the stripped contaminants flows out of the cleaning tank (6), and after the scum is removed by the circulating filter device (9), it returns to the liquid preparation tank (1) through the return pipeline (10), so that the cleaning medium is in a circulating state. The aluminum alloy electronic precision parts fixed in the cleaning tank are completely immersed in the cleaning medium and electrolyzed for 7 minutes.

[0146] Mode 3: Simultaneously activate the micro / nano bubble generator and the low-temperature plasma generator. The circulating pump (2) delivers the cleaning medium from the liquid preparation tank (1) into the micro / nano bubble generator (3). The micro / nano bubble generator (3) uses nitrogen as the gas source to generate micro / nano bubbles with an average particle size of 10-30 μm and a gas flow rate of 1.0 m³ / s. 3 / h, bubbles are injected into the cleaning tank (6) along with the cleaning medium; the low-temperature plasma generator (4) located on the side wall of the cleaning tank (6) (using nitrogen as the working gas, with a discharge power of 80W) generates excited state N2, N2 + Active species such as ·N and a small amount of ·OH are introduced into the cleaning medium through a microporous aeration head and dissolved in the cleaning medium. A DC power supply (8) is connected to apply a DC voltage of 10V. The aluminum alloy electronic precision component fixed in the cleaning tank is used as an electrode (7). The micro-nano bubble field, plasma field, electrolytic electric field and cleaning medium work together on the surface of the workpiece. The cleaning medium carrying the removed contaminants flows out of the cleaning tank (6), and after the scum is removed by the circulation filter device (9), it returns to the liquid preparation tank (1) through the return pipeline (10), so that the cleaning medium is in a circulating flow state. The aluminum alloy electronic precision component fixed in the cleaning tank is completely immersed in the cleaning medium and electrolyzed for 7 minutes.

[0147] Mode 4: Based on Mode 3, turn on the ultrasonic titanium alloy vibrating plate (5) located at the bottom of the cleaning tank (6) (ultrasonic frequency 35kHz, ultrasonic power density 12W / L, continuous working mode), and the aluminum alloy electronic precision parts fixed in the cleaning tank are completely immersed in the cleaning medium and electrolyzed for 7 minutes.

[0148] The results showed that, based on the residual amount of particulate impurities, the residual amounts of the normal mode, mode 1, mode 2, mode 3, and mode 4 were 8.0 mg / m³. 2 5.5 mg / m 2 4.2 mg / m 2 1.2 mg / m 2 and <0.5 mg / m 2 The corresponding removal rates were 46.7%, 63.3%, 72.0%, 92.0%, and >96.7%, respectively. The ordinary mode group had excessive residual impurities; mode one had limited detergency; mode two had insufficient removal of impurities in dead corners; mode three significantly reduced trace impurities; and mode four significantly reduced trace oil and passivation layer, with residual oil <0.01 g / m³. 2 The passivation layer thickness was reduced from 20 nm to <2 nm, and the workpiece was free from corrosion and white spot discoloration, meeting the high-end electronic cleanroom standards.

Claims

1. A cleaning tank for cleaning metal surfaces, comprising: The tank is used to hold the workpiece to be cleaned. A plasma generator installed on the side wall of the tank for introducing active species into the cleaning medium inside the tank. and An ultrasonic generator is installed on the side wall and / or bottom of the tank.

2. The cleaning tank as described in claim 1, characterized in that, The cleaning tank has one or more of the following characteristics: The working gas of the plasma generator is air, oxygen, or nitrogen; the working gas is excited by plasma to generate one or more active species, which include one or more of free radicals, atoms, excited-state molecules, ions, and ozone. The discharge power of the plasma generator is 30-320W; The ultrasonic generator is an ultrasonic titanium alloy vibrating plate; preferably, the ultrasonic frequency of the ultrasonic generator is 20-40kHz, and / or the ultrasonic power density of the ultrasonic generator is 10-30W / L.

3. A system for cleaning metal surfaces, characterized in that, The system includes: A mixing tank is used to store cleaning media; A circulating pump is used to transport the cleaning medium from the liquid preparation tank to the micro / nano bubble generator; Micro / nano bubble generator, used to generate micro / nano bubbles; The cleaning tank as described in claim 1 or 2; A circulating filtration device is used to receive the cleaning medium carrying stripped contaminants flowing out of the cleaning tank and to remove scum from it; and The return pipeline is used to return the cleaning medium filtered by the circulating filter to the liquid preparation tank, so that the cleaning medium is in a state of circulation. The liquid preparation tank, circulating pump, micro-nano bubble generator, cleaning tank, circulating filter device and return pipeline are connected in sequence to form a cleaning medium circulation loop. The system also includes a DC power supply and electrodes, the electrodes including the workpiece to be cleaned and an auxiliary electrode; the DC power supply and the electrodes are connected to form an electrolytic circuit. Preferably, the system has one or more of the following features: The system also includes a plasma generator installed in the return pipeline; The micro / nano bubble generator produces bubbles with an average particle size of 50 nm-50 μm and a gas flow rate of 0.3-2 m³ / h. 3 / h; The DC voltage of the DC power supply is 3-15V.

4. The method for cleaning metal surfaces using the system described in claim 3, characterized in that, The method includes: fixing the workpiece to be cleaned in a cleaning tank, providing a cleaning medium in a liquid preparation tank, and turning on a plasma generator, an ultrasonic generator, and an optional micro / nano bubble generator to clean the workpiece. Preferably, the cleaning medium does not include surfactants, emulsifiers, and defoamers; Preferably, the cleaning medium is an alkaline solution, an acidic solution, or a neutral salt solution; preferably, the alkaline solution has a mass fraction of 4%-15%, and the solute in the alkaline solution is preferably selected from one or more of sodium hydroxide, sodium carbonate, and trisodium phosphate; preferably, the acidic solution has a mass fraction of 3%-10%, and the solute in the acidic solution is preferably selected from one or more of hydrochloric acid, sulfuric acid, and citric acid; preferably, the neutral salt solution has a mass fraction of 4%-12%, and the solute in the neutral salt solution is preferably selected from one or two of sodium sulfate and sodium nitrate. Preferably, the temperature of the cleaning medium is 20-60°C; Preferably, the method further includes pretreatment, which includes dust removal and high-pressure coarse washing; Preferably, the method further includes post-treatment, which includes pure water spraying, neutralization and passivation, and low-temperature drying.

5. The method as described in claim 4, characterized in that, The method has one or more of the following characteristics: The cleaning medium is an alkaline solution, wherein the solute in the alkaline solution is selected from one or more of sodium hydroxide, sodium carbonate, and trisodium phosphate; the mass fraction of the alkaline solution is 4%-12%; and the temperature of the cleaning medium is 30-60℃. The gas source for the micro-nano bubble generator is air; The micro / nano bubble generator produces bubbles with an average particle size of 50 nm-50 μm and a gas flow rate of 0.5-2 m³ / h. 3 / h; The working gas of the plasma generator is air; The discharge power of the plasma generator is 50-300W.

6. The method as described in claim 4, characterized in that, The method further includes turning on the DC power supply, wherein the electrolysis temperature is 30-60℃ and the DC voltage is 5-12V; Preferably, the method has one or more of the following features: The cleaning medium is an alkaline solution, wherein the solute in the alkaline solution is selected from one or more of sodium hydroxide, sodium carbonate, and trisodium phosphate; the mass fraction of the alkaline solution is 5%-15%. The gas source for the micro-nano bubble generator is air; The micro / nano bubble generator produces bubbles with an average particle size of 50 nm-50 μm and a gas flow rate of 0.5-2 m³ / h. 3 / h; The working gas of the plasma generator is air; The discharge power of the plasma generator is 60-320W.

7. The method as described in claim 4, characterized in that, The method has one or more of the following characteristics: The cleaning medium is an acid solution, and the solute in the acid solution is selected from one or more of hydrochloric acid, sulfuric acid and citric acid; more preferably, the mass fraction of the acid solution is 3%-9%; the temperature of the cleaning medium is 25-45℃. The gas source for the micro-nano bubble generator is oxygen. The micro / nano bubble generator produces bubbles with an average particle size of 50 nm-50 μm and a gas flow rate of 0.3-1.5 m³ / s. 3 / h; The working gas of the plasma generator is oxygen. The discharge power of the plasma generator is 40-250W.

8. The method as described in claim 4, characterized in that, The method further includes turning on the DC power supply, wherein the electrolysis temperature is 25-45℃ and the DC voltage is 3-8V; Preferably, the method has one or more of the following features: The cleaning medium is an acid solution, wherein the solute in the acid solution is selected from one or more of hydrochloric acid, sulfuric acid, and citric acid; more preferably, the mass fraction of the acid solution is 3%-10%. The gas source for the micro-nano bubble generator is oxygen. The micro / nano bubble generator produces bubbles with an average particle size of 50 nm-50 μm and a gas flow rate of 0.3-1.5 m³ / s. 3 / h; The working gas of the plasma generator is oxygen. The discharge power of the plasma generator is 50-280W.

9. The method as described in claim 4, characterized in that, The method further includes turning on the DC power supply, wherein the electrolysis temperature is 20-50℃ and the DC voltage is 6-15V; Preferably, the method has one or more of the following features: The cleaning medium is a neutral salt solution, wherein the solute in the neutral salt solution is selected from one or both of sodium sulfate and sodium nitrate; more preferably, the mass fraction of the neutral salt solution is 4%-12%. The gas source for the micro-nano bubble generator is nitrogen. The micro / nano bubble generator produces bubbles with an average particle size of 50 nm-50 μm and a gas flow rate of 0.4-1.8 m³ / s. 3 / h; The working gas of the plasma generator is nitrogen. The discharge power of the plasma generator is 30-200W.

10. The application of the cleaning tank of claim 1 or 2, the system of claim 3, and the method of any one of claims 4-9 in the industrial batch cleaning of precision parts; preferably, the precision parts are carbon steel, stainless steel, or aluminum alloy.

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