A silicon-free non-etching descaling agent suitable for the surface of 7-series aluminum alloy and a preparation method and application thereof

Abstract

The present application relates to a kind of non-silicon non-etching scale removers for 7 series aluminum alloy surface, which is applicable to the field of aluminum alloy cleaning technology in environmental-friendly metal surface treatment technology, and more specifically, the scale remover comprises the following components with the following concentrations: 3000-5000 ppm of boron-containing compounds; 500-2000 ppm of polyhydroxy-containing compounds; 200-400 ppm of acrylic compounds; 300-600 ppm of corrosion inhibitors; 300-600 ppm of accelerators; 1000-2000 ppm of surfactants; and tap water in the remainder.The pH value of the scale remover is 9.5-10.5.The scale remover does not contain strong alkali, silicon, phosphorus, fluorine, nitrate or nitrite, and any toxic heavy metal, and is applicable to immersion or spraying.The treatment temperature is 50°C, the treatment time is 5-10 minutes for immersion and 1-3 minutes for spraying, and the scale remover can improve the daoyin value, color (Lab value) and gloss of the substrate surface, meet the current environmental protection and use requirements, and has good market prospects.

Description

Technical Field

[0001] This invention relates to the field of environmentally friendly metal surface treatment technology and aluminum alloy cleaning technology, specifically to a silicon-free, non-etching descaling agent suitable for synergistic optimization of 7-series aluminum alloy surfaces, its preparation method, and its application. Background Technology

[0002] 7-series aluminum alloys belong to the Al-Zn-Cu series of ultra-hard aluminum alloys. Among the eight aluminum plate series, they are considered to have superior performance and are widely used in aerospace applications, hence the common name "aerospace aluminum." Due to their hardness approaching that of steel, and their resistance to exfoliation corrosion, stress corrosion cracking, fatigue, and high fracture toughness, these alloys have been widely used in recent years, not only for load-bearing components in aircraft, landing gear, rockets, propellers, and spacecraft, but also for major consumer electronics manufacturers, used in the production of mobile phone frames and back covers, computer casings, and other products. The manufacturing process of 7-series aluminum alloys involves various processes. After pretreatment (such as anodizing and chemical conversion), high-gloss chamfering and milling are sometimes performed, and cleaning is an essential post-processing step. In practical operation, the pre-treated products have very strict requirements for the dyne value, color (Lab value), and gloss of the aluminum alloy surface. Therefore, the requirements for descaling agents are very high. They must ensure that the dirt is completely and quickly cleaned, and that the surface dyne value is large, while also ensuring that the product's gloss is not affected and that no etching occurs. This is very different from traditional acidic or alkaline silicone-containing cleaning agents. When 7-series aluminum alloys are in solutions that are too acidic or alkaline, a violent dissolution reaction occurs, resulting in surface etching and a reduction in metallic gloss. Furthermore, when the cleaning bath contains silicon ions or the silicon content of the aluminum alloy is too high, under certain conditions, yellow or brown sodium aluminosilicate can form, which easily remains on the surface, thus affecting the product's gloss and washability. Therefore, with increasingly stringent environmental protection requirements, cleaning agents must not only be silicone-free, but also phosphorus-free, fluorine-free, nitrate- or nitrite-free, free of any strong acids or alkalis, and free of toxic heavy metals. This has significantly increased the difficulty of developing descaling agents.

[0003] Many domestic companies have conducted extensive research on this topic and applied for numerous patents. For example, patent CN107740109A discloses a cleaning agent and its preparation method. While this cleaning agent is applicable to 5, 6, and 7 series aluminum alloys, the Lab value and gloss of the product after cleaning 7 series aluminum alloys are significantly affected, the anodized film is easily corroded, and the formula contains a large amount of strong acid, causing great inconvenience to the post-cleaning processing and production process. Patent CN105112978A describes a cleaning agent that can also clean 5, 6, and 7 series aluminum alloys, but when used to clean 7 series aluminum alloys that have undergone anodizing and CNC machining, it corrodes the oxide film on the aluminum alloy surface, greatly affecting the gloss of the cleaned product. Patent 104294295A discloses an aluminum alloy cleaning agent and a method for pretreatment of aluminum alloy for silver plating. In order to obtain good detergency, a certain amount of strong alkali needs to be added to the cleaning agent, which reduces the gloss of the product after cleaning. Patent CN110644010A discloses a 7-series aluminum alloy cleaning agent and a preparation method. Although the cleaning agent does not contain strong acid and strong alkali, it still needs to add sodium polyphosphate as a cleaning aid, which does not meet environmental protection requirements.

[0004] Therefore, it is essential to develop a green and environmentally friendly descaling agent for 7-series aluminum alloys that provides good cleaning performance while ensuring that the dyne value, color (Lab value), and gloss of the product surface are not affected. Summary of the Invention

[0005] The purpose of this invention is to overcome many problems of existing cleaning processes, such as high corrosion, reduced surface gloss, and lack of environmental friendliness, and to provide a green and environmentally friendly descaling agent for 7-series aluminum alloys that has a good cleaning effect and can ensure that the dyne value, color (Lab value) and gloss of the product surface are not affected.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] A silicon-free, non-etching descaling agent suitable for synergistic optimization of 7-series aluminum alloy surfaces, comprising the following components at the following concentrations:

[0008] Boron-containing compounds in the range of 3000–5000 ppm;

[0009] Compounds containing polyhydroxyl groups in the range of 500–2000 ppm;

[0010] Acrylic acid compounds, 200–400 ppm;

[0011] Corrosion inhibitors of 300–600 ppm;

[0012] Accelerators of 300–600 ppm;

[0013] Surfactants of 1000–2000 ppm;

[0014] Remaining tap water;

[0015] The pH value of the silicon-free non-etching descaling agent that is synergistically optimized for 7-series aluminum alloy surfaces ranges from 9.5 to 10.5.

[0016] The 7-series aluminum alloy surface synergistic optimization type silicon-free non-etching descaling agent of the present invention is alkaline. After contacting the substrate, a variety of high-quality surfactants selected by the present invention wet the substrate surface, reduce the adhesion strength between the dirt and the substrate, expand the original pores in the scale layer and create new pores. Then, the active particles formed by the combination of boron-containing compounds and polyhydroxyl groups uniformly dispersed in the solution quickly break down the internal structure of the dirt, so as to achieve the purpose of non-etching descaling.

[0017] Preferably, the surfactant comprises a mixture of alkylphenol polyoxyethylene ether-10, alkylphenol polyoxyethylene ether-7, and alkylphenol polyoxyethylene ether-13.

[0018] The surfactant of this invention is a mixture of alkylphenol polyoxyethylene ether-10, alkylphenol polyoxyethylene ether-7 and alkylphenol polyoxyethylene ether-13. The three have a synergistic effect, reduce surface tension, form internal micelles, and improve the wetting, penetration and emulsifying ability of the surfactant.

[0019] Preferably, the surfactant comprises a mixture of the alkylphenol polyoxyethylene ether-10, the alkylphenol polyoxyethylene ether-7, and the alkylphenol polyoxyethylene ether-13 in a mass ratio of 1-2:1-2:1-4.

[0020] Preferably, the surfactant comprises a mixture of the alkylphenol polyoxyethylene ether-10, the alkylphenol polyoxyethylene ether-7, and the alkylphenol polyoxyethylene ether-13 in a mass ratio of 1:1:4.

[0021] Alkylphenol polyoxyethylene ether-10, alkylphenol polyoxyethylene ether-7, and alkylphenol polyoxyethylene ether-13, the numbers following them represent the degree of polymerization, i.e., the number of polyoxyethylene functional groups. Different degrees of polymerization result in different surface tensions and wettability. Generally, a higher degree of polymerization leads to greater surface tension and better hydrophilic wettability.

[0022] Experiments revealed that during the cleaning process, surfactants adsorb onto the workpiece surface. When alkylphenol polyoxyethylene ether-10, alkylphenol polyoxyethylene ether-7, and alkylphenol polyoxyethylene ether-13 are mixed in a mass ratio of 1–2:1–2:1–4, they exhibit excellent cleaning effects. Unexpectedly, the experiments also found that a mass ratio of 1:1:4 for these three surfactants resulted in the highest interfacial adsorption density, indicating the highest interfacial effectiveness. This significantly reduced interfacial tension at extremely low concentrations, achieving a synergistic effect and further enhancing degreasing performance.

[0023] Preferably, the boron-containing compound includes one or more of sodium metaborate and potassium metaborate; the compound containing multiple hydroxyl groups includes one or more of sodium gluconate, sodium gluconate, and sodium citrate.

[0024] Preferably, the corrosion inhibitor comprises one or more of 2-amino-2-methyl-1-propanol, 3-amino-4-octanol, and 2-amino-2-ethyl-1,3-propanediol.

[0025] The improved color (Lab value) and gloss of 7-series aluminum alloys after descaling are closely related to the corrosion inhibition performance of the descaling agent. To descale without etching, it is crucial to help the substrate resist corrosion and dissolution while removing the scale. This invention utilizes the lone pair electrons of nitrogen atoms to release free small molecules through hydrolysis and dissociation reactions, or to adsorb them onto the substrate surface via free radicals, thereby inhibiting the substrate corrosion process.

[0026] Preferably, the acrylic compound includes one or more of acrylate copolymers, sodium acrylate, and potassium acrylate; the accelerator includes one or more of sodium fluoride and potassium fluoride, but is not limited thereto.

[0027] This invention's silicone-free, non-etching descaling agent first utilizes the synergistic effect of multiple selected high-quality surfactants to wet the substrate surface upon contact, reducing surface tension, decreasing the adhesion strength between dirt and the substrate, expanding the existing pores in the scale layer, and creating new pores. Then, active particles formed by the combination of boron-containing compounds and polyhydroxy compounds uniformly dispersed in the solution break down the internal structure of the dirt, achieving the purpose of descaling and increasing the dyne value of the substrate surface. This invention also utilizes the electrostatic and adsorption effects of acrylic compounds. On the one hand, by utilizing the interaction between the negative ion groups in the acrylic compounds and the cationic groups in the solution, an electrostatic attraction is formed, preventing the aggregation and precipitation of active particles. On the other hand, the hydrophilicity of acrylic compound molecules can form an adsorption layer on the surface of the active particles, changing their surface energy and hydrophilicity, increasing particle dispersibility, improving the compatibility between particles and the descaling agent, and allowing the particles to be better dispersed in the medium. At the same time, boron atoms have a bactericidal effect, which can effectively reduce the reproduction capacity of microorganisms in the descaling agent and better ensure the stability of cleaning performance.

[0028] The accelerator has a strong penetrating ability and can quickly penetrate into the substrate. It will first undergo an electrochemical reaction with the alloy phase on the substrate surface, which can effectively promote the dissolution of dirt and the adsorption of free small molecules or free radicals.

[0029] Preferably, the pH is adjusted by a pH stabilizer, said pH stabilizer including triethanolamine.

[0030] Triethanolamine is the preferred pH stabilizer. It has weak basicity and can react with acids to form salts or esters, allowing the system's pH to remain relatively low and easily stabilized within a suitable range. Furthermore, due to the lone pair of electrons on its nitrogen atom, triethanolamine forms ligands that chelate with boron-containing compounds, inhibiting corrosion.

[0031] Preferably, the components include the following concentrations:

[0032] 4000 ppm of sodium metaborate;

[0033] 1000 ppm sodium gluconate;

[0034] 300 ppm of acrylate copolymers;

[0035] 500 ppm of 2-amino-2-methyl-1-propanol;

[0036] 500 ppm sodium fluoride;

[0037] 2000 ppm surfactant;

[0038] Remaining tap water;

[0039] The pH value of the silicon-free non-etching descaling agent that is synergistically optimized for 7-series aluminum alloy surfaces includes 10.0.

[0040] Experiments have shown that the descaling agent formed using sodium metaborate (4000 ppm), sodium gluconate (1000 ppm), acrylate copolymer (300 ppm), 2-amino-2-methyl-1-propanol corrosion inhibitor (500 ppm), sodium fluoride (500 ppm) as an accelerator, and a mixture of alkylphenol polyoxyethylene ether-10, alkylphenol polyoxyethylene ether-7, and alkylphenol polyoxyethylene ether-13 as a surfactant, with the solution pH adjusted to 10.0, exhibits the most outstanding performance and is the optimal choice.

[0041] An application of a silicon-free, non-etching descaling agent, as described above, for synergistic optimization of 7-series aluminum alloy surfaces, used for descaling metal surfaces.

[0042] Preferably, it is used to improve the dyne value, Lab value and gloss of the substrate surface after descaling the metal surface.

[0043] Preferably, the metal comprises a 7-series aluminum alloy.

[0044] This product is applied to the surface of 7-series aluminum alloys for non-etching descaling, and the solution is silicon-free. The general method is to immerse the 7-series aluminum alloy in the descaling agent for treatment, effectively removing surface contaminants without etching. After rinsing and drying, the dyne value, color (Lab value), and gloss of the substrate surface do not decrease. Treatment methods include immersion or spraying, with a treatment temperature of 50℃ and treatment times of 5–10 minutes for immersion and 1–3 minutes for spraying.

[0045] This cleaning agent is free of strong alkalis, silicon, phosphorus, fluorine, nitrates or nitrites, and any toxic heavy metals. It can be used for immersion or spraying. The treatment temperature is 50℃, and the treatment time is immersion for 5-10 minutes and spraying for 1-3 minutes. It can also improve the dyne value, color (Lab value), and gloss of the substrate surface, meeting current environmental protection and usage requirements and having good market prospects.

[0046] Compared with the prior art, implementing the present invention has the following beneficial effects:

[0047] (1) The silicon-free non-etching descaling agent described in this invention can effectively remove dirt from the surface of 7-series aluminum alloys without etching. After washing and drying, it can also improve the dyne value, color (Lab value) and gloss of the substrate surface.

[0048] (2) The silicon-free non-etching descaling agent of the present invention utilizes the synergistic effect of a variety of high-quality surfactants, and then utilizes the active particles formed by the combination of boron-containing compounds and polyhydroxy compounds uniformly dispersed in the solution to break down the internal structure of the dirt, achieving a cleaning rate of over 99%.

[0049] (3) The silicon-free non-etching descaling agent of the present invention is mainly composed of boron, polyhydroxy compounds and acrylic compounds. It does not contain strong alkali, silicon, phosphorus, fluorine, nitrate or nitrite and any toxic heavy metals. At the same time, the boron atoms contained therein have a bactericidal effect, which can effectively reduce the reproduction capacity of microorganisms in the descaling agent and better ensure the stability of cleaning performance. Attached Figure Description

[0050] Figure 1 The surface of the substrate after cleaning with the silicon-free, non-etching descaling agent for 7-series aluminum alloy prepared in Example 1 is uniform and free of corrosion.

[0051] Figure 2 The surface of the substrate after cleaning with the silicon-free, non-etching descaling agent for 7-series aluminum alloy prepared in Example 2 is uniform and free of corrosion.

[0052] Figure 3 The surface of the substrate after cleaning with the silicon-free, non-etching descaling agent for 7-series aluminum alloy prepared in Example 3 is uniform and free of corrosion.

[0053] Figure 4 The surface of the substrate after cleaning with the silicon-free, non-etching descaling agent for 7-series aluminum alloy prepared in Example 4 is uniform and free of corrosion.

[0054] Figure 5 The surface of the substrate after cleaning with the silicon-free, non-etching descaling agent for 7-series aluminum alloy prepared in Example 5 is uniform and free of corrosion.

[0055] Figure 6 The surface of the substrate after cleaning with the silicon-free, non-etching descaling agent for 7-series aluminum alloy prepared in Example 6 is uniform and free of corrosion.

[0056] Figure 7 The substrate surface of the 7-series aluminum alloy prepared as Comparative Example 1 still had some black residue after cleaning with the silicon-free non-etching descaling agent, which proves that the degreasing performance of the cleaning agent is poor.

[0057] Figure 8 The substrate surface of the 7-series aluminum alloy prepared in Comparative Example 2 after cleaning with a silicon-free, non-etching descaling agent showed some corrosion.

[0058] Figure 9 The substrate surface of the 7-series aluminum alloy prepared in Comparative Example 3 after cleaning with a silicon-free, non-etching descaling agent showed some corrosion.

[0059] Figure 10 The substrate surface of the 7-series aluminum alloy prepared in Comparative Example 4 after cleaning with a silicon-free, non-etching descaling agent showed some corrosion.

[0060] Figure 11The substrate surface of the 7-series aluminum alloy prepared in Comparative Example 5 after cleaning with a silicon-free, non-etching descaling agent showed some corrosion.

[0061] Figure 12 The substrate surface of the 7-series aluminum alloy prepared as Comparative Example 6 still had some black residue after cleaning with the silicon-free non-etching descaling agent, proving that the degreasing performance of the cleaning agent was poor.

[0062] Figure 13 The substrate surface of the 7-series aluminum alloy prepared as Comparative Example 7 still had some black residue after cleaning with the silicon-free non-etching descaling agent, proving that the degreasing performance of the cleaning agent was poor. Detailed Implementation

[0063] To make the technical solution of the present invention easier to understand, the present invention will be further described in detail below with reference to specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments are not intended to limit the present invention. Modifications or substitutions made to the methods, steps, or conditions of the present invention without departing from the spirit and substance of the present invention are all within the scope of the present invention. Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art.

[0064] Example 1

[0065] A silicon-free, non-etching descaling agent suitable for synergistic optimization of 7-series aluminum alloy surfaces, comprising the following components at the following concentrations:

[0066] The mixture contains 4000 ppm sodium metaborate, 1000 ppm sodium gluconate, 300 ppm acrylate copolymer, 500 ppm 2-amino-2-methyl-1-propanol corrosion inhibitor, 500 ppm sodium fluoride accelerator, and 2000 ppm surfactant of a mixture of alkylphenol polyoxyethylene ether-10, alkylphenol polyoxyethylene ether-7, and alkylphenol polyoxyethylene ether-13. The alkylphenol polyoxyethylene ether-10, alkylphenol polyoxyethylene ether-7, and alkylphenol polyoxyethylene ether-13 are mixed in a mass ratio of 1:1:4.

[0067] Dissolve each component in water by stirring, adjust the pH of the solution to 10.0, and add pure water to make the volume of the cleaning solution 1000 mL to obtain the cleaning solution described in this embodiment.

[0068] The method for cleaning 7-series aluminum alloys using the silicon-free, non-etching descaling agent described in this embodiment includes the following steps:

[0069] (1) Pretreatment: ① Cut a 50mm×100mm 7075 aluminum alloy sample and drill a hole, and connect an iron wire at the drilled hole; ② Remove the adhesive on the sample surface using chemical methods and wipe it clean for later use.

[0070] (2) Place the 7075 aluminum alloy sample pretreated in step (1) into the descaling solution prepared in this embodiment. The temperature of the descaling solution is 50°C. Immerse for 5 minutes to complete the descaling. Take out the sample, wash it with water, and then dry it or let it air dry naturally.

[0071] SEM image of the substrate surface after cleaning is shown below. Figure 1 As shown, the substrate surface is uniformly descaled and free of corrosion.

[0072] Example 2

[0073] A silicon-free, non-etching descaling agent suitable for synergistic optimization of 7-series aluminum alloy surfaces, comprising the following components at the following concentrations:

[0074] The mixture contains 4000 ppm sodium metaborate, 1000 ppm sodium gluconate, 300 ppm acrylate copolymer, 500 ppm 2-amino-2-methyl-1-propanol corrosion inhibitor, 500 ppm sodium fluoride accelerator, and 2000 ppm surfactant of a mixture of alkylphenol polyoxyethylene ether-10, alkylphenol polyoxyethylene ether-7, and alkylphenol polyoxyethylene ether-13. The alkylphenol polyoxyethylene ether-10, alkylphenol polyoxyethylene ether-7, and alkylphenol polyoxyethylene ether-13 are mixed in a mass ratio of 1:1:1.

[0075] Dissolve each component in water by stirring, adjust the pH of the solution to 10.0, and add pure water to make the volume of the cleaning solution 1000 mL to obtain the cleaning solution described in this embodiment.

[0076] The method for cleaning 7-series aluminum alloys using the silicon-free, non-etching descaling agent described in this embodiment includes the following steps:

[0077] (1) Pretreatment: ① Cut a 50mm×100mm 7075 aluminum alloy sample and drill a hole, and connect an iron wire at the drilled hole; ② Remove the adhesive on the sample surface using chemical methods and wipe it clean for later use.

[0078] (2) Place the 7075 aluminum alloy sample pretreated in step (1) into the descaling solution prepared in this embodiment. The temperature of the descaling solution is 50°C. Immerse for 5 minutes to complete the descaling. Take out the sample, wash it with water, and then dry it or let it air dry naturally.

[0079] SEM image of the substrate surface after cleaning is shown below. Figure 2 As shown, the substrate surface is uniformly descaled and free of corrosion.

[0080] Example 3

[0081] A silicon-free, non-etching descaling agent suitable for synergistic optimization of 7-series aluminum alloy surfaces, comprising the following components at the following concentrations:

[0082] The mixture contains 4000 ppm sodium metaborate, 1000 ppm sodium gluconate, 300 ppm acrylate copolymer, 500 ppm 2-amino-2-methyl-1-propanol corrosion inhibitor, 500 ppm sodium fluoride accelerator, and 2000 ppm surfactant of a mixture of alkylphenol polyoxyethylene ether-10, alkylphenol polyoxyethylene ether-7, and alkylphenol polyoxyethylene ether-13. The alkylphenol polyoxyethylene ether-10, alkylphenol polyoxyethylene ether-7, and alkylphenol polyoxyethylene ether-13 are mixed in a mass ratio of 1:1:2.

[0083] Dissolve each component in water by stirring, adjust the pH of the solution to 10.0, and add pure water to make the volume of the cleaning solution 1000 mL to obtain the cleaning solution described in this embodiment.

[0084] The method for cleaning 7-series aluminum alloys using the silicon-free, non-etching descaling agent described in this embodiment includes the following steps:

[0085] (1) Pretreatment: ① Cut a 50mm×100mm 7075 aluminum alloy sample and drill a hole, and connect an iron wire at the drilled hole; ② Remove the adhesive on the sample surface using chemical methods and wipe it clean for later use.

[0086] (2) Place the 7075 aluminum alloy sample pretreated in step (1) into the descaling solution prepared in this embodiment. The temperature of the descaling solution is 50°C. Immerse for 5 minutes to complete the descaling. Take out the sample, wash it with water, and then dry it or let it air dry naturally.

[0087] SEM image of the substrate surface after cleaning is shown below. Figure 3 As shown, the substrate surface is uniformly descaled and free of corrosion.

[0088] Example 4

[0089] A silicon-free, non-etching descaling agent suitable for synergistic optimization of 7-series aluminum alloy surfaces, comprising the following components at the following concentrations:

[0090] The mixture contains 4000 ppm sodium metaborate, 1000 ppm sodium gluconate, 300 ppm acrylate copolymer, 500 ppm 2-amino-2-methyl-1-propanol corrosion inhibitor, 500 ppm sodium fluoride accelerator, and 2000 ppm surfactant of a mixture of alkylphenol polyoxyethylene ether-10, alkylphenol polyoxyethylene ether-7, and alkylphenol polyoxyethylene ether-13. The alkylphenol polyoxyethylene ether-10, alkylphenol polyoxyethylene ether-7, and alkylphenol polyoxyethylene ether-13 are mixed in a mass ratio of 2:2:1.

[0091] Dissolve each component in water by stirring, adjust the pH of the solution to 10.0, and add pure water to make the volume of the cleaning solution 1000 mL to obtain the cleaning solution described in this embodiment.

[0092] The method for cleaning 7-series aluminum alloys using the silicon-free, non-etching descaling agent described in this embodiment includes the following steps:

[0093] (1) Pretreatment: ① Cut a 50mm×100mm 7075 aluminum alloy sample and drill a hole, and connect an iron wire at the drilled hole; ② Remove the adhesive on the sample surface using chemical methods and wipe it clean for later use.

[0094] (2) Place the 7075 aluminum alloy sample pretreated in step (1) into the descaling solution prepared in this embodiment. The temperature of the descaling solution is 50°C. Immerse for 5 minutes to complete the descaling. Take out the sample, wash it with water, and then dry it or let it air dry naturally.

[0095] SEM image of the substrate surface after cleaning is shown below. Figure 4 As shown, the substrate surface is uniformly descaled and free of corrosion.

[0096] Example 5

[0097] A silicon-free, non-etching descaling agent suitable for synergistic optimization of 7-series aluminum alloy surfaces, comprising the following components at the following concentrations:

[0098] The accelerator consists of 3000 ppm potassium metaborate, 500 ppm sodium gluconate, 300 ppm sodium acrylate, 300 ppm 3-amino-4-octanol, and 300 ppm potassium fluoride; and 1000 ppm surfactant is a mixture of alkylphenol polyoxyethylene ether-10, alkylphenol polyoxyethylene ether-7, and alkylphenol polyoxyethylene ether-13. The alkylphenol polyoxyethylene ether-10, alkylphenol polyoxyethylene ether-7, and alkylphenol polyoxyethylene ether-13 are mixed in a mass ratio of 1:1:4.

[0099] Dissolve each component in water by stirring, adjust the pH of the solution to 10.0, and add pure water to make the volume of the cleaning solution 1000 mL to obtain the cleaning solution described in this embodiment.

[0100] The method for cleaning 7-series aluminum alloys using the silicon-free, non-etching descaling agent described in this embodiment includes the following steps:

[0101] (1) Pretreatment: ① Cut a 50mm×100mm 7075 aluminum alloy sample and drill a hole, and connect an iron wire at the drilled hole; ② Remove the adhesive on the sample surface using chemical methods and wipe it clean for later use.

[0102] (2) Place the 7075 aluminum alloy sample pretreated in step (1) into the descaling solution prepared in this embodiment. The temperature of the descaling solution is 50°C. Immerse for 10 minutes to complete the descaling. Take out the sample, wash it with water, and then dry it or let it air dry naturally.

[0103] SEM image of the substrate surface after cleaning is shown below. Figure 5As shown, the substrate surface is uniformly descaled and free of corrosion.

[0104] Example 6

[0105] A silicon-free, non-etching descaling agent suitable for synergistic optimization of 7-series aluminum alloy surfaces, comprising the following components at the following concentrations:

[0106] The accelerator consists of 4000 ppm sodium metaborate, 1000 ppm sodium citrate, 300 ppm potassium acrylate, 600 ppm 2-amino-2-ethyl-1,3-propanediol, and 500 ppm sodium fluoride; and 1500 ppm surfactant is a mixture of alkylphenol polyoxyethylene ether-10, alkylphenol polyoxyethylene ether-7, and alkylphenol polyoxyethylene ether-13. The alkylphenol polyoxyethylene ether-10, alkylphenol polyoxyethylene ether-7, and alkylphenol polyoxyethylene ether-13 are mixed in a mass ratio of 1:1:4.

[0107] Dissolve each component in water by stirring, adjust the pH of the solution to 10.0, and add pure water to make the volume of the cleaning solution 1000 mL to obtain the cleaning solution described in this embodiment.

[0108] The method for cleaning 7-series aluminum alloys using the silicon-free, non-etching descaling agent described in this embodiment includes the following steps:

[0109] (1) Pretreatment: ① Cut a 50mm×100mm 7075 aluminum alloy sample and drill a hole, and connect an iron wire at the drilled hole; ② Remove the adhesive on the sample surface using chemical methods and wipe it clean for later use.

[0110] (2) Place the 7075 aluminum alloy sample pretreated in step (1) into the descaling solution prepared in this embodiment. The temperature of the descaling solution is 50°C. Spray for 2 minutes to complete the descaling. Take out the sample, wash it with water, and then dry it or let it air dry naturally.

[0111] SEM image of the substrate surface after cleaning is shown below. Figure 6 As shown, the substrate surface is uniformly descaled and free of corrosion.

[0112] Comparative Example 1

[0113] A silicon-free, non-etching descaling agent suitable for synergistic optimization of 7-series aluminum alloy surfaces, comprising the following components at the following concentrations:

[0114] Sodium gluconate 1000 ppm, acrylate copolymer 300 ppm, 2-amino-2-methyl-1-propanol corrosion inhibitor 500 ppm, sodium fluoride 500 ppm as an accelerator, and a surfactant mixture of alkylphenol polyoxyethylene ether-10, alkylphenol polyoxyethylene ether-7, and alkylphenol polyoxyethylene ether-13 at a mass ratio of 1:1:4.

[0115] Dissolve each component in water by stirring, adjust the pH of the solution to 10.0, and add pure water to make the volume of the cleaning solution 1000 mL to obtain the cleaning solution described in this embodiment.

[0116] The method for cleaning 7-series aluminum alloys using the silicon-free, non-etching descaling agent described in this embodiment includes the following steps:

[0117] (1) Pretreatment: ① Cut a 50mm×100mm 7075 aluminum alloy sample and drill a hole, and connect an iron wire at the drilled hole; ② Remove the adhesive on the sample surface using chemical methods and wipe it clean for later use.

[0118] (2) Place the 7075 aluminum alloy sample pretreated in step (1) into the descaling solution prepared in this embodiment. The temperature of the descaling solution is 50°C. Immerse for 5 minutes to complete the descaling. Take out the sample, wash it with water, and then dry it or let it air dry naturally.

[0119] SEM image of the substrate surface after cleaning is shown below. Figure 7 As shown, some black residue exists on the surface of the substrate, indicating that the cleaning agent has poor degreasing performance.

[0120] Comparative Example 2

[0121] A silicon-free, non-etching descaling agent suitable for synergistic optimization of 7-series aluminum alloy surfaces, comprising the following components at the following concentrations:

[0122] Sodium metaborate 4000ppm, acrylate copolymer 300ppm, 2-amino-2-methyl-1-propanol corrosion inhibitor 500ppm, sodium fluoride 500ppm as an accelerator, and a surfactant mixture of alkylphenol polyoxyethylene ether-10, alkylphenol polyoxyethylene ether-7, and alkylphenol polyoxyethylene ether-13 at a mass ratio of 1:1:4.

[0123] Dissolve each component in water by stirring, adjust the pH of the solution to 10.0, and add pure water to make the volume of the cleaning solution 1000 mL to obtain the cleaning solution described in this embodiment.

[0124] The method for cleaning 7-series aluminum alloys using the silicon-free, non-etching descaling agent described in this embodiment includes the following steps:

[0125] (1) Pretreatment: ① Cut a 50mm×100mm 7075 aluminum alloy sample and drill a hole, and connect an iron wire at the drilled hole; ② Remove the adhesive on the sample surface using chemical methods and wipe it clean for later use.

[0126] (2) Place the 7075 aluminum alloy sample pretreated in step (1) into the descaling solution prepared in this embodiment. The temperature of the descaling solution is 50°C. Immerse for 5 minutes to complete the descaling. Take out the sample, wash it with water, and then dry it or let it air dry naturally.

[0127] SEM image of the substrate surface after cleaning is shown below. Figure 8 As shown, the substrate surface is partially damaged, proving that the cleaning agent has a certain degree of corrosiveness.

[0128] Comparative Example 3

[0129] A silicon-free, non-etching descaling agent suitable for synergistic optimization of 7-series aluminum alloy surfaces, comprising the following components at the following concentrations:

[0130] The mixture contains 4000 ppm sodium metaborate, 1000 ppm sodium gluconate, 500 ppm 2-amino-2-methyl-1-propanol corrosion inhibitor, 500 ppm sodium fluoride accelerator, and 2000 ppm surfactant of a mixture of alkylphenol polyoxyethylene ether-10, alkylphenol polyoxyethylene ether-7, and alkylphenol polyoxyethylene ether-13. The alkylphenol polyoxyethylene ether-10, alkylphenol polyoxyethylene ether-7, and alkylphenol polyoxyethylene ether-13 are mixed in a mass ratio of 1:1:4.

[0131] Dissolve each component in water by stirring, adjust the pH of the solution to 10.0, and add pure water to make the volume of the cleaning solution 1000 mL to obtain the cleaning solution described in this embodiment.

[0132] The method for cleaning 7-series aluminum alloys using the silicon-free, non-etching descaling agent described in this embodiment includes the following steps:

[0133] (1) Pretreatment: ① Cut a 50mm×100mm 7075 aluminum alloy sample and drill a hole, and connect an iron wire at the drilled hole; ② Remove the adhesive on the sample surface using chemical methods and wipe it clean for later use.

[0134] (2) Place the 7075 aluminum alloy sample pretreated in step (1) into the descaling solution prepared in this embodiment. The temperature of the descaling solution is 50°C. Immerse for 5 minutes to complete the descaling. Take out the sample, wash it with water, and then dry it or let it air dry naturally.

[0135] SEM image of the substrate surface after cleaning is shown below. Figure 9As shown, the substrate surface is partially damaged, proving that the cleaning agent has a certain degree of corrosiveness.

[0136] Comparative Example 4

[0137] A silicon-free, non-etching descaling agent suitable for synergistic optimization of 7-series aluminum alloy surfaces, comprising the following components at the following concentrations:

[0138] The accelerator consists of 4000 ppm sodium metaborate, 1000 ppm sodium gluconate, 300 ppm acrylate copolymers, and 500 ppm sodium fluoride; the surfactant consists of a mixture of alkylphenol polyoxyethylene ether-10, alkylphenol polyoxyethylene ether-7, and alkylphenol polyoxyethylene ether-13 at a mass ratio of 1:1:4.

[0139] Dissolve each component in water by stirring, adjust the pH of the solution to 10.0, and add pure water to make the volume of the cleaning solution 1000 mL to obtain the cleaning solution described in this embodiment.

[0140] The method for cleaning 7-series aluminum alloys using the silicon-free, non-etching descaling agent described in this embodiment includes the following steps:

[0141] (1) Pretreatment: ① Cut a 50mm×100mm 7075 aluminum alloy sample and drill a hole, and connect an iron wire at the drilled hole; ② Remove the adhesive on the sample surface using chemical methods and wipe it clean for later use.

[0142] (2) Place the 7075 aluminum alloy sample pretreated in step (1) into the descaling solution prepared in this embodiment. The temperature of the descaling solution is 50°C. Immerse for 5 minutes to complete the descaling. Take out the sample, wash it with water, and then dry it or let it air dry naturally.

[0143] SEM image of the substrate surface after cleaning is shown below. Figure 10 As shown, the substrate surface is partially damaged, proving that the cleaning agent has a certain degree of corrosiveness.

[0144] Comparative Example 5

[0145] A silicon-free, non-etching descaling agent suitable for synergistic optimization of 7-series aluminum alloy surfaces, comprising the following components at the following concentrations:

[0146] Sodium metaborate 4000 ppm, sodium gluconate 1000 ppm, acrylate copolymer 300 ppm, 2-amino-2-methyl-1-propanol corrosion inhibitor 500 ppm, and surfactant 2000 ppm of a mixture of alkylphenol polyoxyethylene ether-10, alkylphenol polyoxyethylene ether-7, and alkylphenol polyoxyethylene ether-13. Alkylphenol polyoxyethylene ether-10, alkylphenol polyoxyethylene ether-7, and alkylphenol polyoxyethylene ether-13 are mixed in a mass ratio of 1:1:4.

[0147] Dissolve each component in water by stirring, adjust the pH of the solution to 10.0, and add pure water to make the volume of the cleaning solution 1000 mL to obtain the cleaning solution described in this embodiment.

[0148] The method for cleaning 7-series aluminum alloys using the silicon-free, non-etching descaling agent described in this embodiment includes the following steps:

[0149] (1) Pretreatment: ① Cut a 50mm×100mm 7075 aluminum alloy sample and drill a hole, and connect an iron wire at the drilled hole; ② Remove the adhesive on the sample surface using chemical methods and wipe it clean for later use.

[0150] (2) Place the 7075 aluminum alloy sample pretreated in step (1) into the descaling solution prepared in this embodiment. The temperature of the descaling solution is 50°C. Immerse for 5 minutes to complete the descaling. Take out the sample, wash it with water, and then dry it or let it air dry naturally.

[0151] SEM image of the substrate surface after cleaning is shown below. Figure 11 As shown, the substrate surface is partially damaged, proving that the cleaning agent has a certain degree of corrosiveness.

[0152] Comparative Example 6

[0153] A silicon-free, non-etching descaling agent suitable for synergistic optimization of 7-series aluminum alloy surfaces, comprising the following components at the following concentrations:

[0154] Sodium metaborate 4000ppm, sodium gluconate 1000ppm, acrylate copolymer 300ppm, 2-amino-2-methyl-1-propanol corrosion inhibitor 500ppm, sodium fluoride 500ppm as an accelerator.

[0155] Dissolve each component in water by stirring, adjust the pH of the solution to 10.0, and add pure water to make the volume of the cleaning solution 1000 mL to obtain the cleaning solution described in this embodiment.

[0156] The method for cleaning 7-series aluminum alloys using the silicon-free, non-etching descaling agent described in this embodiment includes the following steps:

[0157] (1) Pretreatment: ① Cut a 50mm×100mm 7075 aluminum alloy sample and drill a hole, and connect an iron wire at the drilled hole; ② Remove the adhesive on the sample surface using chemical methods and wipe it clean for later use.

[0158] (2) Place the 7075 aluminum alloy sample pretreated in step (1) into the descaling solution prepared in this embodiment. The temperature of the descaling solution is 50°C. Immerse for 5 minutes to complete the descaling. Take out the sample, wash it with water, and then dry it or let it air dry naturally.

[0159] SEM image of the substrate surface after cleaning is shown below. Figure 12 As shown, some black residue exists on the surface of the substrate, indicating that the cleaning agent has poor degreasing performance.

[0160] Comparative Example 7

[0161] A silicon-free, non-etching descaling agent suitable for synergistic optimization of 7-series aluminum alloy surfaces, comprising the following components at the following concentrations:

[0162] The mixture contains 4000 ppm sodium metaborate, 1000 ppm sodium gluconate, 300 ppm acrylate copolymer, 500 ppm 2-amino-2-methyl-1-propanol corrosion inhibitor, 500 ppm sodium fluoride accelerator, and 2000 ppm surfactant of a mixture of alkylphenol polyoxyethylene ether-10, alkylphenol polyoxyethylene ether-7, and alkylphenol polyoxyethylene ether-13. The alkylphenol polyoxyethylene ether-10, alkylphenol polyoxyethylene ether-7, and alkylphenol polyoxyethylene ether-13 are mixed in a mass ratio of 1:1:4.

[0163] Dissolve each component in water by stirring, adjust the pH of the solution to 8.0, and add pure water to make the volume of the cleaning solution 1000 mL to obtain the cleaning solution described in this embodiment.

[0164] The method for cleaning 7-series aluminum alloys using the silicon-free, non-etching descaling agent described in this embodiment includes the following steps:

[0165] (1) Pretreatment: ① Cut a 50mm×100mm 7075 aluminum alloy sample and drill a hole, and connect an iron wire at the drilled hole; ② Remove the adhesive on the sample surface using chemical methods and wipe it clean for later use.

[0166] (2) Place the 7075 aluminum alloy sample pretreated in step (1) into the descaling solution prepared in this embodiment. The temperature of the descaling solution is 50°C. Immerse for 5 minutes to complete the descaling. Take out the sample, wash it with water, and then dry it or let it air dry naturally.

[0167] SEM image of the substrate surface after cleaning is shown below. Figure 13 As shown, some black residue exists on the surface of the substrate, indicating that the cleaning agent has poor degreasing performance.

[0168] Experimental Example 1

[0169] Cleaning ability test

[0170] Ten untreated 7075 aluminum alloy samples were selected. Using JB / T 4323.2-2019 "Water-based Metal Cleaning Agents" as a reference standard, the substrate surfaces were first cleaned with isopropanol, ethanol, and distilled water, respectively. The samples were dried and weighed, recorded as m1. Artificial oil was evenly applied to the substrate surface, left to stand for 20 minutes, and the accumulated oil at the bottom was scraped off, weighed, and recorded as m2. The descaling agents prepared in Examples 1-6 and Comparative Examples 1-7 were heated to 50°C, and the treated 7075 aluminum alloy samples were then immersed in the agents for 5 minutes to remove scale. After descaling, the samples were washed with water and then heated and dried for 20 minutes, weighed, and recorded as m3. The cleaning rate η was calculated using the following formula: η%=(m2-m3) / (m2-m1)×100%

[0171] The following data was obtained:

[0172] Table 1. Cleaning rate results for different embodiments

[0173] Test sample number Cleaning rate (%) Example 1 99.97％ Example 2 99.53％ Example 3 99.60％ Example 4 99.51％ Example 5 99.35％ Example 6 99.42％ Comparative Example 1 92.67％ Comparative Example 2 98.65％ Comparative Example 3 97.34％ Comparative Example 4 98.16％ Comparative Example 5 98.67％ Comparative Example 6 89.22％ Comparative Example 7 92.61％

[0174] The test data above show that the silicon-free, non-etching descaling agents for 7-series aluminum alloys prepared in Examples 1-6 have good cleaning efficiency, reaching over 99%. In particular, Example 1 achieved an astonishing cleaning efficiency of 99.97%, which fully demonstrates the excellent synergistic effect of the compounding of nonionic surfactants with different degrees of polymerization, especially when alkylphenol polyoxyethylene ether-10, alkylphenol polyoxyethylene ether-7, and alkylphenol polyoxyethylene ether-13 are mixed in a mass ratio of 1:1:4. Furthermore, the combined action of boron-containing compounds, polyhydroxy compounds, acrylic compounds, corrosion inhibitors, and accelerators achieves rapid removal of dirt. In contrast, Comparative Example 1, lacking boron-containing compounds; Comparative Example 2, lacking polyhydroxy compounds; Comparative Example 3, lacking acrylic compounds; Comparative Example 4, lacking corrosion inhibitors; Comparative Example 5, lacking accelerators; and Comparative Example 6, lacking surfactants, all showed a significant decrease in cleaning efficiency.

[0175] Experimental Example 2

[0176] Dyne value test

[0177] Table 2. Test results of dyne pen for different embodiments.

[0178] Test sample number Test results of No. 58 Daine pen Example 1 OK Example 2 OK Example 3 OK Example 4 OK Example 5 OK Example 6 OK Comparative Example 1 ND Comparative Example 2 ND Comparative Example 3 ND Comparative Example 4 ND Comparative Example 5 ND Comparative Example 6 ND Comparative Example 7 ND

[0179] The test data above shows that after cleaning with the silicon-free, non-etching descaling agent for 7-series aluminum alloys prepared in Examples 1-6, the substrate surface can pass the dyne value test with a No. 58 pen, which indicates that the surface energy is higher than or equal to 58 mN / m and has good hydrophilicity.

[0180] Experimental Example 3

[0181] Color (Lab value) and gloss test

[0182] To more intuitively illustrate the differences before and after cleaning, a colorimeter was used in this invention for color difference analysis: the color space is represented by Lab values, L values ​​represent color lightness, a represents red-green value, and b represents yellow-blue value. The Lab values ​​and gloss GS of 7-series aluminum alloy samples were tested before and after cleaning, and the specific test results are shown in Table 3.

[0183] Table 3. Lab value and gloss test results for different embodiments.

[0184]

[0185]

[0186] The test data above show that after cleaning with the silicon-free non-etching descaling agent for 7-series aluminum alloys prepared in Examples 1-6 and Comparative Examples 1-7, only the ΔLab value of the substrate surface in Examples 1-6 was less than 5, and the GS value was improved. This indicates that the components of the silicon-free non-etching descaling agent for 7-series aluminum alloys described in this invention work together to not only achieve synergistic effects, but also prevent etching, and the dyne value, color (Lab value), and gloss of the substrate surface are not reduced.

[0187] Test Example 4

[0188] Salt spray resistance test

[0189] Ten untreated 7075 aluminum alloy samples were selected and immersed in the silicon-free non-etching descaling agents for 7-series aluminum alloys prepared in Examples 1-6 and Comparative Examples 1-7, respectively, under the same conditions. The working solution temperature was heated to 50°C and immersed for 5 minutes. After immersion, they were washed with water and then immersed in a 3% ammonium molybdate solution for 10 minutes. After cleaning and drying, they were subjected to neutral salt spray tests according to the standard GB / T 10125-1997 Artificial Atmosphere Corrosion Test (Salt Spray Test). The specific test results are shown in Table 4.

[0190]

[0191]

[0192] The test data above show that the silicon-free, non-etching descaling agents for 7-series aluminum alloys prepared in Examples 1-6, after cleaning and treatment with ammonium molybdate solution, exhibit better salt spray performance than the silicon-free, non-etching descaling agents for 7-series aluminum alloys prepared in Comparative Examples 1-7. This indicates that the components of the silicon-free, non-etching descaling agent for 7-series aluminum alloys described in this application not only exert a synergistic effect but also provide better adhesion conditions for post-treatment, resulting in superior corrosion resistance.

[0193] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising a reference structure" does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0194] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A silicon-free, non-etching descaling agent suitable for synergistic optimization of 7-series aluminum alloy surfaces, characterized in that, The components include the following concentrations: Boron-containing compounds in the range of 3000-5000 ppm; Compounds containing polyhydroxyl groups in the range of 500-2000 ppm; Acrylic acid compounds, 200-400 ppm; Corrosion inhibitors of 300~600 ppm; Accelerators of 300-600 ppm; Surfactants of 1000~2000 ppm; Remaining tap water; The pH value of the silicon-free non-etching descaling agent suitable for synergistic optimization of 7-series aluminum alloy surfaces includes 9.5~10.5; the boron-containing compound is one or more of sodium metaborate and potassium metaborate; the surfactant includes a mixture of alkylphenol polyoxyethylene ether-10, alkylphenol polyoxyethylene ether-7, and alkylphenol polyoxyethylene ether-13 in a mass ratio of 1~2:1~2:1~4; the compound containing polyhydroxyl groups is one or more of sodium gluconate, sodium gluconate, and sodium citrate; the corrosion inhibitor includes one or more of 2-amino-2-methyl-1-propanol, 3-amino-4-octanol, and 2-amino-2-ethyl-1,3-propanediol; the acrylic compound is one or more of acrylate copolymers, sodium acrylate, and potassium acrylate; and the accelerator includes one or more of sodium fluoride and potassium fluoride.

2. The silicon-free, non-etching descaling agent for synergistic optimization of 7-series aluminum alloy surfaces as described in claim 1, characterized in that, The surfactant comprises a mixture of alkylphenol polyoxyethylene ether-10, alkylphenol polyoxyethylene ether-7, and alkylphenol polyoxyethylene ether-13 in a mass ratio of 1:1:

4.

3. The silicon-free, non-etching descaling agent for synergistic optimization of 7-series aluminum alloy surfaces as described in claim 1, characterized in that, pH is adjusted by a pH stabilizer, including triethanolamine.

4. The silicon-free, non-etching descaling agent for synergistic optimization of 7-series aluminum alloy surfaces as described in claim 1, characterized in that, The components include the following concentrations: 4000 ppm of sodium metaborate; 1000 ppm sodium gluconate; 300 ppm of acrylate copolymers; 500 ppm of 2-amino-2-methyl-1-propanol; 500 ppm sodium fluoride; 2000 ppm surfactant; Remaining tap water; The pH value of the silicon-free non-etching descaling agent that is synergistically optimized for 7-series aluminum alloy surfaces includes 10.

0.

5. The application of the silicon-free, non-etching descaling agent as described in claim 1, suitable for synergistic optimization of 7-series aluminum alloy surfaces, characterized in that, Used for descaling metal surfaces.

6. The application of the silicon-free, non-etching descaling agent for synergistic optimization of 7-series aluminum alloy surfaces as described in claim 5, characterized in that, Used to improve the dyne value, Lab value, and gloss of the substrate surface after descaling metal surfaces.

7. The application of the silicon-free, non-etching descaling agent for synergistic optimization of 7-series aluminum alloy surfaces as described in claim 5, characterized in that, The metal includes 7-series aluminum alloys.

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