Phosphorus-free and nitrogen-free film removing agent for aluminum and aluminum alloy and preparation method thereof

Abstract

The present application relates to the technical field of electroplating, in particular to IPC C23G1, more particularly to a phosphorus-free and nitrogen-free film removing agent for aluminum and aluminum alloy and a preparation method thereof. The present application provides a phosphorus-free and nitrogen-free film removing agent for aluminum and aluminum alloy, which has strong corrosion resistance and high oxidizability. The preparation raw materials include acid agent, metal salt, oxidizing agent, stabilizer, corrosion inhibitor, chelating agent, bactericidal and algicidal agent, and water. The phosphorus-free and nitrogen-free film removing agent for aluminum and aluminum alloy prepared in the present application has excellent oxidizability and strong corrosion resistance, can effectively remove the film on the surface of aluminum and aluminum metal, and has fast film removing speed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electroplating, in particular to IPC C23G1, and more particularly to a phosphorus-free and nitrogen-free film remover for aluminum and aluminum alloy and a preparation method thereof. BACKGROUND

[0002] Aluminum and its alloys are widely used in many fields due to their excellent electrical, mechanical and machining properties, and are called the metal materials with the largest use and the widest application among non-ferrous metals. The surfaces of aluminum and its alloys are usually treated by processes such as alkaline solution corrosion, chemical polishing, electrolytic polishing, chemical etching and anodic oxidation to meet the requirements of performance and appearance. During these process treatments, the dirt, stains, oxide scales, intermetallic compounds, impurities, black films, silicon elements and inert elements remaining on the surface of the aluminum alloy must be removed through a film removal process to ensure the smooth progress of each process.

[0003] The commonly used film removal process for aluminum surface treatment is sulfuric acid method, nitric acid method and chromic acid method. The film remover in the sulfuric acid method is usually formed by mixing high-concentration sulfuric acid, hydrogen peroxide and hydrochloric acid, which has the advantage of low production cost. However, the sulfuric acid method has a slow dissolution rate of copper and nickel deposited on the aluminum due to immersion in the etching solution, and cannot remove some organic black films formed by macromolecular compounds. In addition, the sulfuric acid method has a long operation time, and it is difficult for sulfuric acid to form a passivation film on the surface of aluminum, and snowflake-shaped corrosion spots may occur after long-term immersion.

[0004] The nitric acid method and the chromic acid method have strong solubility of the deposited ash, which can obtain a clean, bright and uniform passivated surface of the aluminum material and avoid the generation of snowflake-shaped spots, and can meet the ash removal requirements of various aluminum materials. However, the nitric acid vapor volatilized from the nitric acid solution and the nitrogen oxide products decomposed therefrom not only pollute the air environment, but also easily lead to eutrophication of water bodies, resulting in the death of fish and aquatic organisms. Hexavalent chromium in the chromic acid method is a strong carcinogen, and fluoride is also a highly dangerous chemical. In order to protect the health of the operators and the environment, the use of these chemicals should be avoided.

[0005] In the existing patents, CN201710931051.X discloses an aluminum and aluminum alloy film remover and its application, which comprises 200-600 g / L of composite acid, 30-150 g / L of composite oxidizing agent, 2-20 g / L of silicon stripping agent, 0.1-20 g / L of corrosion inhibitor, 0.1-50 g / L of stabilizer, 0.1-50 g / L of ash film remover and water; but the time for removing the film is long, and part of the film remains. SUMMARY

[0006] In order to solve the problems in the prior art, the first aspect of the present application provides a phosphorus-free and nitrogen-free film removal agent for aluminum and aluminum alloy with strong corrosion resistance and high oxidation, which is prepared from raw materials including an acid agent, a metal salt, an oxidizing agent, a stabilizing agent, a corrosion inhibitor, a chelating agent, a bactericidal and algicidal agent, and water.

[0007] Preferably, the phosphorus-free and nitrogen-free film removal agent for aluminum and aluminum alloy is prepared from raw materials including 120-180 g / L of the acid agent, 20-40 g / L of the metal salt, 30-80 g / L of the oxidizing agent, 5-15 g / L of the stabilizing agent, 0.5-2.5 g / L of the corrosion inhibitor, 3-8 g / L of the chelating agent, and 0.1-2 g / L of the bactericidal and algicidal agent, wherein the solvent for preparing the phosphorus-free and nitrogen-free film removal agent for aluminum and aluminum alloy includes water.

[0008] Preferably, the raw materials for preparing 1 L of the phosphorus-free and nitrogen-free film removal agent for aluminum and aluminum alloy include 120-180 g of the acid agent, 20-40 g of the metal salt, 30-80 g of the oxidizing agent, 5-15 g of the stabilizing agent, 0.5-2.5 g of the corrosion inhibitor, 3-8 g of the chelating agent, and 0.1-2 g of the bactericidal and algicidal agent, and the balance is water.

[0009] Preferably, the acid agent includes one or more of sulfuric acid, boric acid, hydrochloric acid, citric acid, tartaric acid, salicylic acid, acetic acid, oxalic acid, propionic acid, malonic acid, succinic acid, lactic acid, malic acid, benzoic acid, phenylacetic acid, terephthalic acid, o-phthalic acid, benzene sulfonic acid, valeric acid, and maleic acid.

[0010] In a preferred embodiment, the acid agent includes sulfuric acid and o-phthalic acid, and the mass ratio is (8-12):1; further preferably, 10:1.

[0011] Preferably, the metal salt includes one or more of cerium sulfate, cerium carbonate, cerium chloride, cerium oxalate, cerium octoate, iron sulfate, polymeric ferric sulfate, iron carbonate, sodium ferrate, potassium ferrate, lithium ferrate, iron chloride, ferrous chloride, iron oxalate, iron citrate, iron molybdate, and polymeric aluminum ferric chloride.

[0012] Preferably, the oxidizing agent is one or more of hydrogen peroxide, peroxyacetic acid, sodium persulfate, potassium persulfate, potassium permanganate, sodium permanganate, iron permanganate, potassium hydrogen persulfate, sodium chlorate, sodium hypochlorite, sodium percarbonate, sodium perborate, potassium perborate, sodium molybdate, potassium molybdate, sodium tungstate, and potassium tungstate.

[0013] Preferably, the stabilizer is one or more of methanol, ethanol, ethylene glycol, 1-propanol, 2-propanol, glycerol, 1-butanol, 2-butanol, 2-butyl mercaptan, benzyl alcohol, diethylene glycol methyl ether, ethylene glycol dimethyl ether, diethylene glycol ethyl ether, diethylene glycol butyl ether, ethylene glycol monobutyl ether, propylene glycol ethyl ether, phenyl mercaptan, benzyl mercaptan, 2-methyl-1-propanethiol, 3-methyl-1-butanol, 2-methyl-1-butyl mercaptan, 3-methyl-1-butyl mercaptan, sodium silicate, potassium silicate, magnesium silicate, or acrylic acid.

[0014] Preferably, the corrosion inhibitor is one or more of molybdate, benzoate, selenate, cinnamate, phytic acid, nicotinic acid, sulfonic acid, azelaic acid, dimer acid, dextrin, xanthan gum, maleic acid copolymer, siloxone, 1,4-naphthoquinone, a complex of tartaric acid and propargyl alcohol, a complex of organic carboxylic acid and sulfonic aromatic compound.

[0015] In the present application, by adding metal salt, oxidizing agent, and corrosion inhibitor in a mass ratio of 20-40:30-80:0.5-2.5, the compactness of the oxide layer of the passivation film is improved, the formation of snowflake-like spots is reduced, the effect of removing impurities by the film removal agent is improved, and the film removal time is shortened. The present inventors have found that after adding metal salt and oxidizing agent, a passivation film can be formed on the surface of aluminum and aluminum alloy, but some voids exist in the passivation film, and pitting corrosion easily occurs in an acidic solution. After adding sodium molybdate, the sodium molybdate fills into the voids in the passivation film, improving the stability of the passivation film and thus improving the corrosion resistance. Meanwhile, sodium ferrate has good oxidizing properties, and after being compounded with the oxidizing agent, the effect of removing impurities is further improved. In addition, sodium ferrate also has a certain bactericidal effect, and after being compounded with the bactericidal and algicidal agent, bacteria, fungi, and algae in water are reduced, thereby improving the corrosion resistance of the passivation film formed on the surface of aluminum and aluminum alloy.

[0016] Preferably, the molybdate includes one or more of sodium molybdate and potassium molybdate.

[0017] Preferably, the chelating agent is one or more of gluconic acid, gluconate, citric acid, citrate, tartaric acid, tartrate, malic acid, malate, polyacrylic acid, polyacrylate, polyvinyl alcohol, hydrolyzed polymaleic acid, acrylic acid-maleic acid copolymer, acrylic acid-hydroxypropyl acrylate copolymer, acrylic acid-acrylate-sulfonate terpolymer, polyepoxysuccinic acid, and polyepoxysuccinate.

[0018] Preferably, the bactericidal and algicidal agent is one or more of hypochlorite, benzoate, hydrogen peroxide, peroxyacetic acid, formaldehyde, acetaldehyde, glutaraldehyde, phenol, o-chlorophenol, p-chlorophenol, sodium pentachlorophenol, 2,4-dichlorophenol, 2,4,5-trichlorophenol, and 2,2-dihydroxy-5,5'-dichlorobenzene.

[0019] Preferably, the benzoate salt comprises sodium benzoate, potassium benzoate.

[0020] In the present application, the acid agent, sulfuric acid, phthalic acid and oxidizing agent are compounded, wherein the mass ratio of the acid agent and the oxidizing agent is 120-180:30-80, and the mass ratio of sulfuric acid and phthalic acid in the acid agent is (8-12):1, which can effectively remove the manganese, silicon, copper and other elements precipitated to form the hanging ash in the aluminum and aluminum alloy material after the chemical polishing process, the organic black film formed by adsorbing macromolecular compounds after the chemical polishing process and other dirt, stains, oxide skin and silicon elements, and will not corrode the aluminum surface after long-term soaking, and has strong corrosion resistance. Currently commonly used acids such as nitric acid, chromic acid and hydrofluoric acid are used as acid agents, and nitric acid, chromic acid and hydrofluoric acid have great pollution to the working environment, and the subsequent wastewater treatment is complex, therefore, the present inventors select sulfuric acid and phthalic acid with strong efficacy and small pollution in the present application, and the present inventors accidentally find that the concentration of sulfuric acid and phthalic acid selected in the present application is 120-180 g / L and hydrogen peroxide is compounded, which can effectively remove the oxide skin on the surface of aluminum and aluminum alloy, and the inert elements or difficult-to-remove black film such as silicon, manganese, intermetallic compound and organic black film can be rapidly oxidized and decomposed, and a dense passivation film can be easily formed on the surface of aluminum and aluminum alloy with metal salt, stabilizer, corrosion inhibitor, chelating agent and other substances, and the aluminum and aluminum alloy will not easily appear snowflake-shaped corrosion spots after long-term soaking under the concentration.

[0021] In the present application, the acid agent, metal salt, oxidizing agent, stabilizer, corrosion inhibitor, chelating agent, bactericidal and algicidal agent, water and other substances without phosphorus, nitrogen, fluorine, toxic and harmful substances are selected, which can reduce the cost of wastewater treatment and the harm of water eutrophication, protect the health of workers and the environment, and maintain the strong corrosion resistance of aluminum and aluminum alloy after film removal treatment.

[0022] The second aspect of the present application provides a preparation method of a phosphorus-free and nitrogen-free film remover for aluminum and aluminum alloy, which comprises the following steps: mixing an acid agent, a metal salt, an oxidizing agent, a stabilizer, a corrosion inhibitor, a chelating agent, a bactericidal and algicidal agent and water to obtain a phosphorus-free and nitrogen-free film remover for aluminum and aluminum alloy. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 It is a photo of the original aluminum metal sheet in the performance test;

[0024] Figure 2 It is a photo of the aluminum metal sheet after chemical polishing in the performance test;

[0025] Figure 3 It is a photo of the aluminum metal sheet after chemical polishing treated by the film remover prepared in Example 1 in the performance test.

[0026] Figure 4The photo of the aluminum metal sheet after the treatment of the film removing agent prepared in Example 1 + 200 ppm of chloride ions in the performance test.

[0027] Figure 5 The photo of the aluminum metal sheet after the treatment of the film removing agent prepared in Example 1 + 200 ppm of chloride ions in the performance test.

[0028] Figure 6 The photo of the aluminum metal sheet after the treatment of the film removing agent prepared in Example 1 + 200 ppm of chloride ions in the performance test.

[0029] Figure 7 The photo of the aluminum metal sheet after the treatment of the film removing agent prepared in Example 1 + 200 ppm of chloride ions in the performance test.

[0030] Figure 8 The photo of the aluminum metal sheet after the treatment of the film removing agent prepared in Example 1 + 200 ppm of chloride ions in the performance test.

[0031] Figure 9 The photo of the aluminum metal sheet after the treatment of the film removing agent prepared in Example 1 + 200 ppm of chloride ions in the performance test.

[0032] Figure 10 The photo of the aluminum metal sheet after the treatment of the film removing agent prepared in Example 1 + 200 ppm of chloride ions in the performance test.

[0033] Beneficial effects

[0034] 1、In the present application, the acid agent: sulfuric acid, phthalic acid and oxidizing agent are compounded, wherein the mass ratio of the acid agent and the oxidizing agent is 120-180:30-80, and the mass ratio of sulfuric acid and phthalic acid in the acid agent is (8-12):1, which can effectively remove the manganese, silicon, copper and other elements precipitated to form the gray hanging after the chemical polishing process of aluminum and aluminum alloy materials, and the organic black film formed by adsorbing macromolecular compounds after the chemical polishing process, as well as other dirt, stains, oxide skin and silicon elements. Long-term soaking will not corrode the aluminum surface, and the corrosion resistance is strong.

[0035] 2、In the present application, by adding acrylic acid-maleic acid copolymer, gluconate, ethanol and other substances, the mass ratio of the chelating agent (acrylic acid-maleic acid copolymer, gluconate) and the stabilizer (ethanol) is controlled to be 3-8:5-15, which can promote the stability of hydrogen peroxide and potassium persulfate. The present inventor found that the oxidizing agent is easy to decompose under the action of light and temperature. After the addition of acrylic acid-maleic acid copolymer, gluconate, ethanol and other substances, the metal ions can be complexed, the contact between the metal ions and the oxidizing agent is reduced, and the decomposition of the oxidizing agent is further reduced.

[0036] 3、The present application, by adding the mass ratio of 20-40:30-80:0.5-2.5 metal salt, oxidizing agent, corrosion inhibitor, not only improves the compactness of the oxide layer of the passivation film, reduces the formation of snowflake-like spots, but also improves the impurity removal effect of the film remover and shortens the film removal time.

[0037] 4、The present application, by chelating agent, the metal salt and oxidizing agent and other substances form a stable passivation film, high impurity ion tolerance, long time soaking will not corrode the aluminum surface, will not reduce the gloss; resistant to chlorine ion corrosion, even 1500ppm chloride ion, soaking 4 hours will not have corrosion point.

[0038] 5、The present application, the selection does not contain phosphorus, nitrogen, fluorine, toxic and harmful acid agent, metal salt, oxidizing agent, stabilizer, corrosion inhibitor, chelating agent, bactericidal algae agent, water and other substances, in reducing the cost of wastewater treatment and water eutrophication hazards, as well as the health of workers and environmental pollution hazards, at the same time, maintain the strong corrosion resistance of aluminum and aluminum alloy after film removal treatment. DETAILED DESCRIPTION

[0039] Example 1

[0040] The first aspect of the present embodiment provides a phosphorus-free and nitrogen-free film remover for aluminum and aluminum alloy with strong corrosion resistance and high oxidation, and the mass of the preparation raw materials and the preparation raw materials in 1L film remover is shown in Table 1.

[0041] Table 1

[0042]

[0043]

[0044] The sulfuric acid is concentrated sulfuric acid with a mass fraction of 98%. The CAS number of the phthalic acid is 88-99-3. The CAS number of the potassium ferrate is 39469-86-8. The hydrogen peroxide is hydrogen peroxide with a mass fraction of 35%, and the CAS number of the hydrogen peroxide is 101-78-6. The CAS number of the ethanol is 64-17-5. The CAS number of the sodium molybdate is 10102-40-6. The CAS number of the acrylic acid-maleic acid copolymer is 29132-58-9, which is purchased from Pandeng (Shanghai) International Trade Co., Ltd. The CAS number of the sodium benzoate is 532-32-1.

[0045] The second aspect of the present embodiment provides a preparation method of a phosphorus-free and nitrogen-free film remover for aluminum and aluminum alloy, which comprises the following steps: mixing acid agent, metal salt, oxidizing agent, stabilizer, corrosion inhibitor, chelating agent, bactericidal algae agent, and water according to the above mass fraction to obtain a phosphorus-free and nitrogen-free film remover for aluminum and aluminum alloy.

[0046] Example 2

[0047] The first aspect of the present embodiment provides a phosphorus-free and nitrogen-free film removal agent for aluminum and aluminum alloy, which has strong corrosion resistance and high oxidation. The mass of the preparation raw materials and the preparation raw materials in 1 L of the film removal agent is shown in Table 2.

[0048] Table 2

[0049]

[0050]

[0051] The sulfuric acid is concentrated sulfuric acid with a mass fraction of 98%. The CAS number of the phthalic acid is 88-99-3. The CAS number of the potassium ferrate is 39469-86-8. The CAS number of the potassium peroxymonosulfate is 70693-62-8. The CAS number of the ethanol is 64-17-5. The CAS number of the sodium molybdate is 10102-40-6. The CAS number of the sodium gluconate is 527-07-1, which is purchased from Pandeng (Shanghai) International Trade Co., Ltd. The CAS number of the sodium benzoate is 532-32-1.

[0052] The second aspect of the present embodiment provides a preparation method of a phosphorus-free and nitrogen-free film removal agent for aluminum and aluminum alloy, which comprises the following steps: mixing acid agent, metal salt, oxidizing agent, stabilizer, corrosion inhibitor, chelating agent, bactericidal and algicidal agent, and water according to the above mass parts to obtain the phosphorus-free and nitrogen-free film removal agent for aluminum and aluminum alloy.

[0053] Comparative Example 1

[0054] The specific implementation of Comparative Example 1 is the same as that of Example 1, except that the phosphorus-free and nitrogen-free film removal agent for aluminum and aluminum alloy does not contain phthalic acid.

[0055] Comparative Example 2

[0056] The present comparative example provides a phosphorus-free and nitrogen-free film removal agent for aluminum and aluminum alloy. The mass of the preparation raw materials and the preparation raw materials in 1 L of the film removal agent is shown in Table 3.

[0057] Table 3

[0058] Raw materials Specific name Mass (g) in raw materials for preparation of 1 L of film remover Acid agent 98% sulfuric acid 200 Oxidizing agent 35% hydrogen peroxide 50 Water Water Balance

[0059] The sulfuric acid is concentrated sulfuric acid with a mass fraction of 98%; and the hydrogen peroxide is hydrogen peroxide with a mass fraction of 35%.

[0060] Performance test

[0061] 1. Six pieces of aluminum metal sheets (the photo of one piece of the aluminum metal sheet is shown in FIG. 1) are prepared. Figure 1)defatting, water washing 2 times, chemical polishing, and continuing to use the aluminum metal sheet after chemical polishing (a photo of one of the aluminum metal sheets after chemical polishing is shown in Figure 2 ), numbered as ①, ②, ③, ④, ⑤, ⑥, ⑦, respectively, and then washed with water twice, placed in a film removing agent at 25°C for 120 s, taken out, washed with water twice again, and dried for observation. The results are shown in Figures 3 to 10 .

[0062] The film removing agents are as follows:

[0063] ① the film removing agent prepared in Example 1, ② Comparative Example 2, ③ the film removing agent prepared in Example 1 + 200 ppm of chloride ions, ④ Comparative Example 2 + 200 ppm of chloride ions, ⑤ the film removing agent prepared in Example 1 + 1000 ppm of chloride ions, ⑥ Comparative Example 2 + 1000 ppm of chloride ions, and ⑦ the film removing agent prepared in Example 1 + 1500 ppm of chloride ions.

[0064] Results: ① the surface condition is good, no corrosion, and the black film is removed cleanly. ② the black film is not removed cleanly. ③ no corrosion points are generated. ④ corrosion points are generated, which can be seen more clearly after magnification. ⑤ no corrosion points are generated. ⑥ black corrosion points are generated. ⑦ no corrosion points are generated.

Claims

1. A phosphorus-free and nitrogen-free film remover for aluminum and aluminum alloys, characterized in that, The preparation raw material includes 120-180 g / L acid agent, 20-40 g / L metal salt, 30-80 g / L oxidizing agent, 5-15 g / L stabilizer, 0.5-2.5 g / L corrosion inhibitor, 3-8 g / L chelating agent, 0.1-2 g / L bactericidal and algicide, and solvent, wherein the solvent includes water; The metal salt includes one or more of sodium ferrate and potassium ferrate; the oxidizing agent is one or more of hydrogen peroxide and potassium hydrogen persulfate; the stabilizer is ethanol; the corrosion inhibitor is molybdate; the chelating agent is one or more of gluconate and acrylic acid-maleic acid copolymer; and the bactericidal and algicide is benzoate. The acid agent includes sulfuric acid and phthalic acid, and the mass ratio of the sulfuric acid to the phthalic acid is (8-12):

1.

2. A method for producing the non-phosphorus and non-nitrogen film removing agent for aluminum and aluminum alloys according to claim 1, characterized by, The preparation method includes the following steps: mixing the acid agent, the metal salt, the oxidizing agent, the stabilizer, the corrosion inhibitor, the chelating agent, the bactericidal and algicide, and water to obtain the phosphorus-free and nitrogen-free film removing agent for aluminum and aluminum alloy.

Images