Aluminum alloy welding cleaning agent and its preparation method and application

Abstract

The present invention relates to the technical field of welding cleaning agents, and in particular to an aluminum alloy welding cleaning agent and its preparation method and application. The above-mentioned aluminum alloy welding cleaning agent, its raw materials include by mass: 10-20 parts of organic acid, 1-3 parts of modified silica, 0.1-0.5 parts of chelating agent, 1-2 parts of acidic dispersant, 2-5 parts of corrosion inhibitor, 1.1-3 parts of penetrant, 5-10 parts of defoaming agent, and 60-100 parts of water. The formula of the present invention is reasonable and scientific, the preparation is simple, no special equipment is required, and the cleaning ability is strong. Excellent cleaning effect can also be achieved at low temperature, and the time is short, the working efficiency is good, and the oil stains on the metal surface, especially the aluminum alloy surface, have extremely high cleaning efficiency, and the corrosiveness is significantly reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of welding cleaning agents, in particular to an aluminum alloy welding cleaning agent and a preparation method and application thereof. Background Art

[0002] The air-conditioning pipelines of new energy electric vehicles mainly play the role of conducting, transporting and filling refrigerant in the vehicle's refrigeration system. They connect relevant functional components such as the compressor, condenser, expansion valve and evaporator in the system, and use sensors and valves to monitor the temperature, pressure and other parameters of components in different positions of the system and provide real-time feedback.

[0003] The main material used for air conditioning pipes in electric vehicle refrigeration systems is aluminum alloy. Aluminum alloy is the most widely used non-ferrous metal in industry. After processing such as stretching, rolling, stamping, and welding, its surface often retains some lubricating oil, residual flux, and / or oxide layers.

[0004] After aluminum alloy welding, it's necessary to remove surface dirt from the workpiece while maintaining good corrosion resistance. Traditional degreasing methods include high-temperature alkaline chemical degreasing and organic solvent degreasing. High-temperature alkaline chemical degreasing offers advantages such as effective degreasing and low cost, but it can cause severe corrosion to the aluminum alloy surface. While organic solvent degreasing offers good degreasing effects, it also poses challenges such as environmental pollution from volatilization of organic solvents, high costs, and poor corrosion resistance of the aluminum alloy after cleaning.

[0005] Currently, water-based surface cleaners are used to clean oil stains from workpiece surfaces. They can quickly remove oil, dust, sweat, organic matter, inorganic salts, and other dirt and welding residues from aluminum alloy surfaces. However, due to the strong adsorption and active chemical properties of aluminum alloys, ordinary water-based surface cleaners often leave a large amount of residue after use, failing to achieve a clean finish. Furthermore, since most cleaning agents are performed at high temperatures, the cleaning effect is poor at room or even low temperatures. Summary of the Invention

[0006] The purpose of the present invention is to solve the shortcomings of the prior art and to propose an aluminum alloy welding cleaning agent and its preparation method and application.

[0007] The invention discloses an aluminum alloy welding cleaning agent. The raw materials thereof comprise, by mass, 10-20 parts of an organic acid, 1-3 parts of modified silicon dioxide, 0.1-0.5 parts of a chelating agent, 1-2 parts of an acidic dispersant, 2-5 parts of a corrosion inhibitor, 1.1-3 parts of a penetrant, 5-10 parts of a defoaming agent, and 60-100 parts of water.

[0008] Preferably, the organic acid is methanesulfonic acid and / or citric acid.

[0009] Preferably, the chelating agent includes at least one of maleic acid acrylic acid copolymer, gluconic acid, ethylenediaminetetraacetic acid, diisopropyltriaminepentaacetic acid, N,N-bis(2-hydroxyethyl)ethylenediaminetriacetic acid, and polyaspartic acid.

[0010] Preferably, the acidic dispersant is an octa-isomeric carboxylate or a methyl hydroxyethyl decanoate.

[0011] The octa-carbon isomeric carboxylate is preferably sodium isooctanoate or potassium isooctanoate.

[0012] Preferably, the corrosion inhibitor comprises: ammonium fluoroborate and isomeric polycarboxylic acid alcohol amine; the mass ratio of ammonium fluoroborate to isomeric polycarboxylic acid alcohol amine is 4-6:2-4.

[0013] Isomeric polycarboxylic acid alcohol amines are made from polycarboxylic acids and organic amines and do not contain elements such as boron, chlorine, sulfur, and phosphorus.

[0014] Preferably, the penetrant comprises: modified isomeric alcohol ether quaternary ammonium salt and triethylene glycol monobutyl ether; the mass ratio of the modified isomeric alcohol ether quaternary ammonium salt to triethylene glycol monobutyl ether is 1-2:0.1-1.

[0015] Preferably, the defoaming agent is an acetylenediol-modified surfactant, which has low static and dynamic surface tension, improves wetting performance and promotes flow and leveling, and can suppress foam height in the ultrasonic cleaning process. It can be Evonik SURFYNOL 485, RianPont 2704, or Superwet-320.

[0016] Preferably, the modified silica is prepared by the following specific operation: adding mesoporous silica and cerium nitrate to an ethanol aqueous solution and ultrasonically treating for 10-20 minutes, adjusting the pH value of the system to 9-10, continuing the ultrasonic treatment for 1-2 hours, adjusting the pH value of the system to >8.5, adding dopamine and continuing the ultrasonic treatment for 1-3 hours, centrifuging, washing with water, vacuum drying, and crushing.

[0017] More preferably, the mass ratio of mesoporous silica, cerium nitrate and dopamine is 5-15:1-4:1-3.

[0018] More preferably, the ultrasound frequency is 20-30 kHz.

[0019] More preferably, the temperature of the ultrasonic treatment after adjusting the pH value of the system to 9-10 is 60-80°C.

[0020] The preparation method of the above-mentioned aluminum alloy welding cleaning agent comprises the following steps:

[0021] S1. Add organic acid and acidic dispersant to water and stir for 10-30 min at a stirring temperature of 60-70°C, then heat to 75-80°C and stir for 1-2 h to obtain a premix;

[0022] S2. Add modified silica, chelating agent, penetrant, and corrosion inhibitor to the premix and stir evenly, add defoaming agent thereto and stir evenly, adjust the pH of the system to 5.8-6.8, and obtain an aluminum alloy welding cleaning agent.

[0023] The method for using the above-mentioned aluminum alloy welding cleaning agent is to use the above-mentioned aluminum alloy welding cleaning agent to ultrasonically clean the aluminum alloy workpiece after welding at a temperature of 20-50°C; then rinse with water. After the water rinse, the aluminum alloy workpiece is transferred to welding.

[0024] Beneficial effects:

[0025] The invention has a reasonable and scientific formula, is simple to prepare, does not require special equipment, and has strong cleaning ability. It can achieve excellent cleaning effects even at low temperatures, and has a short time and good working efficiency. It has extremely high cleaning efficiency for oil stains on metal surfaces, especially aluminum alloy surfaces, while significantly reducing corrosiveness.

[0026] The present invention utilizes a compound of mesoporous silica and cerium nitrate, deposits cerium hydroxide on the surface of the mesoporous silica in an alkaline environment, and further cooperates with the action of polydopamine. The combination of the two is extremely stable, and the resulting modified silica has extremely high hydrophilic activity, which can significantly enhance the dispersion stability of silica in cleaning agents.

[0027] The modified silica used in the present invention is highly hydrophilic and biocompatible. When combined with an organic acid that does not corrode the aluminum alloy itself, it can effectively remove metal oxides produced after welding. In the ultrasonic process, combined with the modified silica, the impurities on the surface of the aluminum alloy can be removed at a high rate even at low temperatures, and the aluminum alloy has a higher gloss after cleaning.

[0028] The defoaming agent used in the present invention has low static and dynamic surface tension and good wetting performance. It can promote flow and leveling when compounded with modified silica, so that the organic acid in the cleaning agent can better contact and react with the oxide on the surface of the aluminum alloy. It cooperates with the rare earth to form a rare earth oxide film on the surface of the aluminum alloy, effectively preventing the surface reaction of the aluminum alloy, and has excellent corrosion resistance. At the same time, it can significantly suppress the foam height in the ultrasonic cleaning process.

[0029] The cleaning agent system of the present invention is weakly acidic, safe and environmentally friendly, and has excellent penetration ability, good volume expansion performance, and excellent water washability. It greatly improves the cleaning efficiency of aluminum alloy materials and can effectively remove oil stains and oxide films on the surface of aluminum alloy workpieces. The aluminum alloy surface is clean and is very suitable for use by manufacturers of air-conditioning pipes in electric vehicle refrigeration systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The figure is a comparison chart of the wetting power and defoaming performance of the aluminum alloy welding cleaning agents obtained in Example 5 and Comparative Examples 1-3.

[0031] Figure 2 This is a comparison chart of the cleaning capabilities of the aluminum alloy welding cleaning agents obtained in Example 5 and Comparative Examples 1-3.

[0032] Figure 3 The figures show the states of the aluminum alloy workpieces of the fifth group in Example 5 before and after cleaning; wherein (1) shows the state of the aluminum alloy workpieces of the fifth group in Example 5 before cleaning, and (2) shows the state of the aluminum alloy workpieces of the fifth group in Example 5 after cleaning.

[0033] Figure 4 This is a comparison chart of the corrosion weight loss rate and corrosion current density of the aluminum alloy welding cleaning agents obtained in Example 5 and Comparative Examples 1-3. DETAILED DESCRIPTION

[0034] The present invention will be further explained below with reference to specific embodiments.

[0035] The following isomeric polycarboxylic acid alcohol amine was purchased from Xu New Materials (Guangzhou) Co., Ltd. Its model is DX308, which is a non-ionic surfactant, a light yellow to colorless transparent liquid, and a density (20°C) of 1.19 g / cm 3 The pH value (1% aqueous solution) was 8.0-10.0. Alkyne diol-modified surfactant, model RianPont 2704, was purchased from Sichuan Kaibang Chemical Materials Co., Ltd. Octa-isomeric carboxylates, methyl hydroxyethyl deca-isomeric salts, and modified isomeric alcohol ether quaternary ammonium salts were all purchased from Ning Technology (Shenzhen) Co., Ltd.

[0036] Example 1

[0037] The invention discloses an aluminum alloy welding cleaning agent, whose raw materials include: 1000g of methanesulfonic acid, 100g of modified silicon dioxide, 5g of maleic acid-acrylic acid copolymer, 5g of gluconic acid, 100g of sodium isooctanoate, 200g of ammonium fluoroborate, 100g of isomeric polycarboxylic acid alcoholamine, 100g of modified isomeric alcohol ether quaternary ammonium salt, 10g of triethylene glycol monobutyl ether, 500g of acetylene glycol modified surfactant, and 6000g of water.

[0038] The modified silica was prepared by the following specific operation: 50 g of mesoporous silica and 10 g of cerium nitrate were added to 400 g of 50% ethanol aqueous solution and ultrasonically treated for 10 min at an ultrasonic frequency of 20 kHz. The pH value of the system was adjusted to 9-10 with a concentration of 1 mol / L sodium hydroxide, and the ultrasonic treatment was continued for 1 h at an ultrasonic temperature of 60°C to adjust the pH value of the system to >8.5. 10 g of dopamine was added and ultrasonic treatment was continued for 1 h. The product was centrifuged, washed with water, vacuum dried, and crushed.

[0039] The preparation method of the above-mentioned aluminum alloy welding cleaning agent comprises the following steps:

[0040] S1, add methanesulfonic acid and sodium isooctanoate to water and stir for 10 min at a stirring temperature of 60°C, then heat to 75°C and stir for 1 h to obtain a premix;

[0041] S2. Add modified silica, maleic acid acrylic acid copolymer, gluconic acid, modified isomeric alcohol ether quaternary ammonium salt, triethylene glycol monobutyl ether, ammonium fluoroborate, and isomeric polycarboxylic acid alcohol amine to the premix and stir evenly, add acetylene glycol modified surfactant thereto and stir evenly, adjust the pH of the system to 5.8-6.8, and obtain an aluminum alloy welding cleaning agent.

[0042] Example 2

[0043] The invention discloses an aluminum alloy welding cleaning agent, whose raw materials include: 1000g of methanesulfonic acid, 1000g of citric acid, 300g of modified silicon dioxide, 50g of ethylenediaminetetraacetic acid, 200g of potassium isooctanoate, 300g of ammonium fluoroborate, 200g of isomeric polycarboxylic acid alcoholamine, 200g of modified isomeric alcohol ether quaternary ammonium salt, 100g of triethylene glycol monobutyl ether, 1000g of acetylene glycol modified surfactant, and 10000g of water.

[0044] The modified silica was prepared by the following specific operation: 150 g of mesoporous silica and 40 g of cerium nitrate were added to 800 g of 70% ethanol aqueous solution and ultrasonically treated for 20 min at an ultrasonic frequency of 30 kHz. The pH value of the system was adjusted to 9-10 using 2 mol / L sodium hydroxide. The ultrasonic treatment was continued for 2 h at an ultrasonic temperature of 80°C to adjust the pH value of the system to >8.5. 30 g of dopamine was added and ultrasonic treatment was continued for 3 h. The product was centrifuged, washed with water, vacuum dried, and crushed.

[0045] The preparation method of the above-mentioned aluminum alloy welding cleaning agent comprises the following steps:

[0046] S1, adding methanesulfonic acid, citric acid and potassium isooctanoate to water and stirring for 30 min at a stirring temperature of 70°C, then heating to 80°C and stirring for 2 h to obtain a premix;

[0047] S2. Add modified silica, ethylenediaminetetraacetic acid, modified isomeric alcohol ether quaternary ammonium salt, triethylene glycol monobutyl ether, ammonium fluoroborate, and isomeric polycarboxylic acid alcohol amine to the premix and stir evenly, add acetylene glycol modified surfactant thereto and stir evenly, adjust the pH of the system to 5.8-6.8, and obtain an aluminum alloy welding cleaning agent.

[0048] Example 3

[0049] The invention discloses an aluminum alloy welding cleaning agent, whose raw materials include: 1200g of citric acid, 250g of modified silicon dioxide, 20g of polyaspartic acid, 170g of methyl hydroxyethyl decaisocyanate, 220g of ammonium fluoroborate, 170g of isomeric polycarboxylic acid alcoholamine, 120g of modified isomeric alcohol ether quaternary ammonium salt, 70g of triethylene glycol monobutyl ether, 700g of acetylene glycol modified surfactant, and 9000g of water.

[0050] The modified silica was prepared by the following specific operation: 80 g of mesoporous silica and 30 g of cerium nitrate were added to 500 g of 65% ethanol aqueous solution and ultrasonically treated for 12 min at an ultrasonic frequency of 27 kHz. The pH value of the system was adjusted to 9-10 using 1.3 mol / L sodium hydroxide. The ultrasonic treatment was continued for 100 min at an ultrasonic temperature of 65°C to adjust the pH value of the system to >8.5. 25 g of dopamine was added and ultrasonic treatment was continued for 1.5 h. The mixture was centrifuged, washed with water, vacuum dried, and crushed.

[0051] The preparation method of the above-mentioned aluminum alloy welding cleaning agent comprises the following steps:

[0052] S1. Add citric acid and methyl hydroxyethyl decaisocyanate to water and stir for 25 min at a stirring temperature of 62° C., then heat to 79° C. and stir for 80 min to obtain a premix;

[0053] S2. Add modified silica, polyaspartic acid, modified isomeric alcohol ether quaternary ammonium salt, triethylene glycol monobutyl ether, ammonium fluoroborate, and isomeric polycarboxylic acid alcohol amine to the premix and stir evenly, add acetylene glycol modified surfactant thereto and stir evenly, adjust the pH of the system to 5.8-6.8, and obtain an aluminum alloy welding cleaning agent.

[0054] Example 4

[0055] The invention discloses an aluminum alloy welding cleaning agent, whose raw materials include: 1800g of methanesulfonic acid, 150g of modified silicon dioxide, 40g of N,N-bis(2-hydroxyethyl)ethylenediaminetriacetic acid, 130g of methyl hydroxyethyl decaisocyanate, 280g of ammonium fluoroborate, 130g of isomeric polycarboxylic acid alcoholamine, 180g of modified isomeric alcohol ether quaternary ammonium salt, 30g of triethylene glycol monobutyl ether, 900g of acetylene glycol modified surfactant, and 7000g of water.

[0056] The modified silica was prepared by the following specific operation: 120 g of mesoporous silica and 20 g of cerium nitrate were added to 700 g of 55% ethanol aqueous solution and ultrasonically treated for 18 minutes at an ultrasonic frequency of 21 kHz. The pH value of the system was adjusted to 9-10 using 1.7 mol / L sodium hydroxide. The ultrasonic treatment was continued for 80 minutes at an ultrasonic temperature of 75°C to adjust the pH value of the system to >8.5. 15 g of dopamine was added and ultrasonic treatment was continued for 2.5 hours. The product was centrifuged, washed with water, vacuum dried, and crushed.

[0057] The preparation method of the above-mentioned aluminum alloy welding cleaning agent comprises the following steps:

[0058] S1. Add methanesulfonic acid and methyl hydroxyethyl decaisocyanate to water and stir for 15 min at a stirring temperature of 68° C., then heat to 77° C. and stir for 100 min to obtain a premix;

[0059] S2. Add modified silica, N,N-bis(2-hydroxyethyl)ethylenediaminetriacetic acid, modified isomeric alcohol ether quaternary ammonium salt, triethylene glycol monobutyl ether, ammonium fluoroborate, and isomeric polycarboxylic acid alcohol amine to the premix and stir evenly. Add acetylene glycol-modified surfactant thereto and stir evenly. Adjust the pH of the system to 5.8-6.8 to obtain an aluminum alloy welding cleaning agent.

[0060] Example 5

[0061] The invention discloses an aluminum alloy welding cleaning agent, whose raw materials include: 1500g of citric acid, 200g of modified silicon dioxide, 20g of maleic acid acrylic acid copolymer, 10g of gluconic acid, 150g of methyl hydroxyethyl decaisocyanate, 250g of ammonium fluoroborate, 150g of isomeric polycarboxylic acid alcoholamine, 150g of modified isomeric alcohol ether quaternary ammonium salt, 50g of triethylene glycol monobutyl ether, 800g of acetylene glycol modified surfactant, and 8000g of water.

[0062] The modified silica was prepared by the following specific operation: 100 g of mesoporous silica and 25 g of cerium nitrate were added to 600 g of 60% ethanol aqueous solution and ultrasonically treated for 15 min at an ultrasonic frequency of 24 kHz. The pH value of the system was adjusted to 9-10 using 1.5 mol / L sodium hydroxide. The ultrasonic treatment was continued for 90 min at an ultrasonic temperature of 70°C to adjust the pH value of the system to >8.5. 20 g of dopamine was added and ultrasonic treatment was continued for 2 h. The product was centrifuged, washed with water, vacuum dried, and crushed.

[0063] The preparation method of the above-mentioned aluminum alloy welding cleaning agent comprises the following steps:

[0064] S1. Add citric acid and methyl hydroxyethyl decaisocyanate to water and stir for 20 min at a stirring temperature of 65° C., then heat to 78° C. and stir for 90 min to obtain a premix;

[0065] S2. Add modified silica, maleic acid acrylic acid copolymer, gluconic acid, modified isomeric alcohol ether quaternary ammonium salt, triethylene glycol monobutyl ether, ammonium fluoroborate, and isomeric polycarboxylic acid alcohol amine to the premix and stir evenly, add acetylene glycol modified surfactant thereto and stir evenly, adjust the pH of the system to 5.8-6.8, and obtain an aluminum alloy welding cleaning agent.

[0066] Comparative Example 1

[0067] The invention discloses an aluminum alloy welding cleaning agent, whose raw materials include: 1500g of citric acid, 200g of mesoporous silica, 20g of maleic acid acrylic acid copolymer, 10g of gluconic acid, 150g of methyl hydroxyethyl decaisocyanate, 250g of ammonium fluoroborate, 150g of isomeric polycarboxylic acid alcoholamine, 150g of modified isomeric alcohol ether quaternary ammonium salt, 50g of triethylene glycol monobutyl ether, 800g of acetylene glycol modified surfactant, and 8000g of water.

[0068] The preparation method of the above-mentioned aluminum alloy welding cleaning agent comprises the following steps:

[0069] S1. Add citric acid and methyl hydroxyethyl decaisocyanate to water and stir for 20 min at a stirring temperature of 65° C., then heat to 78° C. and stir for 90 min to obtain a premix;

[0070] S2. Add mesoporous silica, maleic acid acrylic acid copolymer, gluconic acid, modified isomeric alcohol ether quaternary ammonium salt, triethylene glycol monobutyl ether, ammonium fluoroborate, and isomeric polycarboxylic acid alcohol amine to the premix and stir evenly, add acetylene glycol modified surfactant thereto and stir evenly, adjust the pH of the system to 5.8-6.8, and obtain an aluminum alloy welding cleaning agent.

[0071] Comparative Example 2

[0072] The invention discloses an aluminum alloy welding cleaning agent, whose raw materials include: 1500g of citric acid, 200g of modified silicon dioxide, 20g of maleic acid acrylic acid copolymer, 10g of gluconic acid, 150g of methyl hydroxyethyl decaisocyanate, 250g of ammonium fluoroborate, 150g of isomeric polycarboxylic acid alcoholamine, 150g of modified isomeric alcohol ether quaternary ammonium salt, 50g of triethylene glycol monobutyl ether, 800g of acetylene glycol modified surfactant, and 8000g of water.

[0073] The modified silica was prepared by the following specific operation: 100 g of mesoporous silica and 25 g of cerium nitrate were added to 600 g of 60% ethanol aqueous solution and ultrasonically treated for 15 min at an ultrasonic frequency of 24 kHz. The pH value of the system was adjusted to 9-10 using 1.5 mol / L sodium hydroxide. The ultrasonic treatment was continued for 90 min at an ultrasonic temperature of 70°C. The product was then centrifuged, washed with water, vacuum dried, and crushed.

[0074] The preparation method of the above-mentioned aluminum alloy welding cleaning agent comprises the following steps:

[0075] S1. Add citric acid and methyl hydroxyethyl decaisocyanate to water and stir for 20 min at a stirring temperature of 65° C., then heat to 78° C. and stir for 90 min to obtain a premix;

[0076] S2. Add modified silica, maleic acid acrylic acid copolymer, gluconic acid, modified isomeric alcohol ether quaternary ammonium salt, triethylene glycol monobutyl ether, ammonium fluoroborate, and isomeric polycarboxylic acid alcohol amine to the premix and stir evenly, add acetylene glycol modified surfactant thereto and stir evenly, adjust the pH of the system to 5.8-6.8, and obtain an aluminum alloy welding cleaning agent.

[0077] Comparative Example 3

[0078] The invention discloses an aluminum alloy welding cleaning agent, whose raw materials include: 1500g of citric acid, 200g of modified silicon dioxide, 20g of maleic acid acrylic acid copolymer, 10g of gluconic acid, 150g of methyl hydroxyethyl decaisocyanate, 250g of ammonium fluoroborate, 150g of isomeric polycarboxylic acid alcoholamine, 150g of modified isomeric alcohol ether quaternary ammonium salt, 50g of triethylene glycol monobutyl ether, 800g of acetylene glycol modified surfactant, and 8000g of water.

[0079] The modified silica was prepared by the following specific operation: 100 g of mesoporous silica was added to 600 g of 60% ethanol aqueous solution, the pH value of the system was adjusted to >8.5, 20 g of dopamine was added and ultrasonic treatment was performed for 2 h at an ultrasonic frequency of 24 kHz, centrifuged, washed with water, vacuum dried, and crushed.

[0080] The preparation method of the above-mentioned aluminum alloy welding cleaning agent comprises the following steps:

[0081] S1. Add citric acid and methyl hydroxyethyl decaisocyanate to water and stir for 20 min at a stirring temperature of 65° C., then heat to 78° C. and stir for 90 min to obtain a premix;

[0082] S2. Add modified silica, maleic acid acrylic acid copolymer, gluconic acid, modified isomeric alcohol ether quaternary ammonium salt, triethylene glycol monobutyl ether, ammonium fluoroborate, and isomeric polycarboxylic acid alcohol amine to the premix and stir evenly, add acetylene glycol modified surfactant thereto and stir evenly, adjust the pH of the system to 5.8-6.8, and obtain an aluminum alloy welding cleaning agent.

[0083] The time from initial wetting to complete settling of a standard canvas sheet in the aluminum alloy welding cleaners obtained in Example 5 and Comparative Examples 1-3 was recorded with reference to GB / T 11983-2008, "Determination of the Wetting Power of Surfactants - Immersion Method." The defoaming properties of the aluminum alloy welding cleaners obtained in Example 5 and Comparative Examples 1-3 were also measured with reference to JB / T 4323-2019, "Water-Based Metal Cleaners."

[0084] like Figure 1 As shown, the wetting power and defoaming performance of the aluminum alloy welding cleaning agent obtained in Example 5 are better than those of Comparative Examples 1-3 (P < 0.05).

[0085] The aluminum alloy welding cleaning agents obtained in Example 5 and Comparative Examples 1-3 were subjected to high and low temperature stability tests. Each group of samples was placed in a 60±1°C environment for 6 hours and in a -5±1°C environment for 24 hours, and the state of each group of samples was observed.

[0086] Table 1 Status of aluminum alloy welding cleaning agents obtained in Example 5 and Comparative Examples 1-3

[0087]

[0088] Twelve identical aluminum alloy workpieces (made of 7075 aluminum alloy) used for air conditioning piping in a new energy vehicle refrigeration system were selected as test specimens. All specimens were cleaned with an organic solvent, dried, cooled, and weighed (m1) to the nearest 0.1 mg. The cleaned aluminum alloy workpieces were immersed in factory stamping lubricant for 30 minutes, removed, and hung to drain for 15 minutes. Excess oil droplets from the bottom of the workpieces were removed with filter paper, and the oil-stained workpiece specimens were accurately weighed (m2). The specimens were randomly divided into four groups (Example 5, Comparative Example 1, Comparative Example 2, and Comparative Example 3). The oil-stained workpiece specimens were ultrasonically cleaned for 5 minutes at room temperature (23°C) using the aluminum alloy welding cleaners obtained in Example 5 and Comparative Examples 1-3, respectively. The samples were then rinsed with water, dried in an oven at 70±2°C for 40 minutes, cooled, and the cleaned aluminum alloy workpieces were accurately weighed (m3).

[0089] The cleaning capacity is expressed by the oil washing rate η, η = (m2-m3) ÷ (m2-m1) × 100%.

[0090] like Figure 2 As shown in the figure, the aluminum alloy welding cleaning agent obtained in Example 5 has the highest oil removal rate and its cleaning ability is better than that of Comparative Examples 1-3 (P < 0.05). Figure 3 shown.

[0091] The aluminum alloy welding cleaners obtained in Example 5 and Comparative Examples 1-3 were submitted for testing. LY12 duralumin was used as the test subject. Copper wires were welded to LY12 aluminum sheets. The non-working areas were encapsulated with epoxy / polyamide resin. The samples were first polished with 240# sandpaper, then with 400# to 2000# water-resistant sandpaper in a stepwise fashion until they reached a mirror finish. The samples were then degreased with acetone, rinsed with distilled water, ultrasonically cleaned with anhydrous ethanol, and dried for later use. Corrosion weight loss tests were then conducted, and the corrosion weight loss rates were calculated. Electrochemical tests were also conducted at room temperature using a CS310 electrochemical workstation in the cleaning agents (i.e., the aluminum alloy welding cleaners obtained in Example 5 and Comparative Examples 1-3).

[0092] like Figure 4As shown, the corrosion weight loss rate and corrosion current density of the aluminum alloy welding cleaning agent obtained in Example 5 are both the smallest, confirming that its corrosiveness is the smallest.

[0093] The applicant believes that this is because the present invention utilizes a compound of mesoporous silica and cerium nitrate, deposits cerium hydroxide on the surface of the mesoporous silica in an alkaline environment, and further cooperates with the action of polydopamine. The combination of the two is extremely stable, and the resulting modified silica has extremely high hydrophilic activity, which can significantly enhance the dispersion stability of silica in the cleaning agent and has good hydrophilicity and biocompatibility. The present invention uses an organic acid that does not corrode the aluminum alloy itself, which can effectively remove the metal oxides produced after welding. In the ultrasonic process, the modified silica can remove impurities on the surface of the aluminum alloy at a high rate even at low temperatures, and the aluminum alloy is more glossy after cleaning. The defoamer used in the present invention has low static and dynamic surface tension and good wetting properties. When combined with the modified silica, it can promote flow and leveling, allowing the organic acid in the cleaning agent to better contact and react with the oxide on the surface of the aluminum alloy. In combination with the rare earth, a rare earth oxide film is formed on the surface of the aluminum alloy, effectively preventing the surface reaction of the aluminum alloy, with excellent corrosion resistance, and significantly suppressing the foam height in the ultrasonic cleaning process.

[0094] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. An aluminum alloy welding cleaning agent, characterized in that: The raw materials include, by mass: 10-20 parts of organic acid, 1-3 parts of modified silicon dioxide, 0.1-0.5 parts of chelating agent, 1-2 parts of acidic dispersant, 2-5 parts of corrosion inhibitor, 1.1-3 parts of penetrant, 5-10 parts of defoaming agent, and 60-100 parts of water; The modified silica is prepared by the following specific operation: mesoporous silica and cerium nitrate are added to an ethanol aqueous solution and ultrasonically treated for 10-20 minutes, the pH value of the system is adjusted to 9-10, the ultrasonic treatment is continued for 1-2 hours, the pH value of the system is adjusted to >8.5, dopamine is added and ultrasonic treatment is continued for 1-3 hours, centrifuged, washed with water, vacuum dried, and crushed.

2. The aluminum alloy welding cleaning agent according to claim 1, characterized in that: The organic acid is methanesulfonic acid and / or citric acid.

3. The aluminum alloy welding cleaning agent according to claim 1, characterized in that: Chelating agents include: At least one of maleic acid acrylic acid copolymer, gluconic acid, ethylenediaminetetraacetic acid, and polyaspartic acid.

4. The aluminum alloy welding cleaning agent according to claim 1, characterized in that: The acidic dispersant is an octa-isomeric carboxylate or a methyl hydroxyethyl decanoate.

5. The aluminum alloy welding cleaning agent according to claim 1, characterized in that: Corrosion inhibitors include: Ammonium fluoroborate and isomeric polycarboxylic acid alcohol amines; the mass ratio of ammonium fluoroborate and isomeric polycarboxylic acid alcohol amines is 4-6:2-4.

6. The aluminum alloy welding cleaning agent according to claim 1, characterized in that: The penetrant comprises: modified isomeric alcohol ether quaternary ammonium salt and triethylene glycol monobutyl ether; the mass ratio of the modified isomeric alcohol ether quaternary ammonium salt and triethylene glycol monobutyl ether is 1-2:0.1-1.

7. The aluminum alloy welding cleaning agent according to claim 1, characterized in that: The mass ratio of mesoporous silica, cerium nitrate and dopamine is 5-15:1-4:1-3; the ultrasonic frequency is 20-30kHz; and the temperature of ultrasonic treatment is 60-80°C after the pH value of the system is adjusted to 9-10.

8. A method for preparing the aluminum alloy welding cleaning agent according to any one of claims 1 to 7, characterized in that: The steps include: S1. Add organic acid and acidic dispersant to water and stir for 10-30 min at a stirring temperature of 60-70°C, then heat to 75-80°C and stir for 1-2 h to obtain a premix; S2. Add modified silica, chelating agent, penetrant, and corrosion inhibitor to the premix and stir evenly, add defoaming agent thereto and stir evenly, adjust the pH of the system to 5.8-6.8, and obtain an aluminum alloy welding cleaning agent.

9. A method for using the aluminum alloy welding cleaning agent according to any one of claims 1 to 7, characterized in that: The aluminum alloy welding cleaning agent according to any one of claims 1 to 7 is used to ultrasonically clean the aluminum alloy workpiece after welding, with the ultrasonic cleaning temperature being 20-50° C.; and then washed with water.

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