Aluminum profile for long-service-life mold and preparation process of aluminum profile

Abstract

The invention discloses a long-life aluminum profile for a mold and a preparation process thereof, and relates to the technical field of aluminum alloys, a zirconium film is loaded on the surface of the aluminum profile, the zirconium film generates an oxide layer on the surface of an aluminum substrate through hydrolysis reaction, micropores in the surface of the aluminum substrate are filled, and the corrosion resistance of the aluminum profile is enhanced. However, the corrosion resistance of a single zirconium film is insufficient, and the corrosion resistance of the aluminum profile is further enhanced by coating the surface of the aluminum profile with the zirconium film with the anti-corrosion liquid. 3-epoxypropoxy propyl triethoxy silane is added into the zirconium conversion liquid, so that the surface of a zirconium film is provided with epoxy groups, the epoxy groups on the surface of the zirconium film and amino groups in the corrosion-resistant chitosan microcapsules form hydrogen bonds and coordinate bonds, the bonding strength of a corrosion-resistant coating is improved, and therefore the corrosion resistance of the aluminum profile for the mold is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of aluminum alloys, and specifically to an aluminum profile for high-life molds and its preparation process. Background Art

[0002] In order to enhance the lifespan of traditional aluminum alloys used in molds, it is necessary to improve the anti-corrosion performance of the aluminum alloys for molds. However, existing anti-corrosion processes mostly rely on chromate conversion coatings. Although a passivation layer can be formed, hexavalent chromium is highly carcinogenic, and the cost of wastewater treatment is extremely high. In addition, the bonding strength between the traditional anodic oxidation film and the aluminum substrate is poor, and it is prone to peeling under high-pressure working conditions.

[0003] In order to solve the above problems, improve the anti-corrosion performance of aluminum materials for molds, and increase the lifespan, the present invention provides an aluminum profile for high-life molds and its preparation process. Summary of the Invention

[0004] The purpose of the present invention is to provide an aluminum profile for high-life molds and its preparation process to solve the problems raised in the prior art.

[0005] To achieve the above purpose, the present invention provides the following technical solutions: A preparation process for an aluminum profile for high-life molds, comprising the following steps: Step 1: Prepare the following raw materials in proportion, by weight percentage: 0.55wt%-0.65wt% Si, 0.2wt%-0.25wt% Cu, 0.1wt%-0.15wt% Mn, 0.85wt%-0.92wt% Mg, 0.06wt%-0.08wt% Cr, 0.01wt%-0.02wt% Ti, 0.1wt%-0.25wt% Fe, with the balance being Al; wherein, the total unavoidable impurities contained in each raw material ≤ 0.1%; Step 2: Melt the raw materials, remove slag, refine, stand, filter, and cast to obtain an aluminum alloy ingot, and then perform homogenization treatment; place it in a mold, extrude and form, cool to 25 - 35°C, perform straightening treatment, and keep warm for 4 - 5h to obtain an aluminum substrate; then perform alkali washing, acid washing, and drying on the aluminum substrate, and wash with deionized water to obtain a pretreated aluminum substrate; Step 3: Immerse the pretreated aluminum substrate in a zirconium conversion solution for 30 - 40 min, wash and dry to obtain an aluminum profile with a zirconium film on the surface; coat the anti-corrosion liquid on the surface of the aluminum profile with a zirconium film on the surface, and dry to obtain an aluminum profile for high-life molds; The zirconium conversion solution uses deionized water as a solvent and includes the following components: 15 - 17 g / L of sodium dihydrogen phosphate, 4 - 6 g / L of 3-glycidoxypropyltriethoxysilane, 5 - 7 g / L of sodium fluoride, 0.4 - 0.6 g / L of zirconium fluoride, 1 - 2 ml / L of phosphoric acid; The anti-corrosion liquid is composed of the following components by weight: 4 - 4.5 parts of sodium fluoride, 5 - 6 parts of chitosan-MOF composite material, 3.5 - 4 parts of fluotitanate, 2.5 - 3 parts of triethanolamine, 2.5 - 3 parts of zinc phosphate, 2.2 - 2.6 parts of potassium permanganate, 1.5 - 2 parts of sodium molybdate, 1.5 - 1.7 parts of ethylenediaminetetraacetic acid, 1.2 - 1.7 parts of malic acid, 1.2 - 1.5 parts of sodium dodecylbenzenesulfonate, 1.2 - 1.5 parts of nickel sulfate, and 90 - 100 parts of deionized water.

[0006] Preferably, the preparation method of the chitosan-MOF composite material is as follows: Take corrosion-resistant chitosan microcapsules and ethanol, stir evenly, add MOF material, stir for 7 - 8 h, centrifuge, wash, and dry to obtain the chitosan-MOF composite material.

[0007] Preferably, the preparation method of the MOF material is as follows: Take 1,3,5-benzenetricarboxylic acid and N,N-dimethylformamide solution, stir evenly to obtain 1,3,5-benzenetricarboxylic acid solution; Stir ammonium cerium(IV) nitrate and deionized water evenly to obtain ammonium cerium(IV) nitrate, add formic acid solution, stir evenly, add the solution to 1,3,5-benzenetricarboxylic acid solution, mix evenly, heat up to 100 °C, react for 15 - 20 min, centrifuge, wash, and dry to obtain the MOF material.

[0008] Preferably, the preparation method of the corrosion-resistant chitosan microcapsules is as follows: Take chitosan and acetic acid, stir evenly to obtain chitosan acetate solution; Take vanillin and chitosan acetate solution, stir evenly to obtain the aqueous phase; Take petroleum ether and liquid paraffin, stir evenly, add Span 80 and Tween 20, stir evenly to obtain the oil phase; Under shear stirring, drop the aqueous phase into the oil phase, emulsify for 15 - 20 min, drop glutaraldehyde, solidify, centrifuge, wash, and dry to obtain the corrosion-resistant chitosan microcapsules.

[0009] Preferably, the mass ratio of the corrosion-resistant chitosan microcapsules to the MOF material is 2.2:(0.3 - 0.5).

[0010] Compared with the prior art, the beneficial effects of the present invention are: 1. The present invention loads a zirconated film on the surface of an aluminum profile. The zirconated film generates an oxide layer on the surface of the aluminum substrate through a hydrolysis reaction, filling the micropores on the surface of the aluminum matrix and enhancing the corrosion resistance of the aluminum profile. However, the corrosion resistance of a single zirconated film is insufficient. In the present invention, an anti-corrosion liquid is coated on the surface of the aluminum profile with a zirconated film, further enhancing the corrosion resistance of the aluminum profile. 3-Glycidoxypropyltriethoxysilane is added to the zirconium conversion solution in the present invention, so that the surface of the zirconated film has epoxy groups. The epoxy groups on the surface of the zirconated film form hydrogen bonds and coordination bonds with the amino groups in the anti-corrosion chitosan microcapsules, improving the bonding strength of the anti-corrosion coating, thereby enhancing the corrosion resistance of the aluminum profile for molds.

[0011] 2. Chitosan has good film-forming properties and can form a dense protective film on the surface of an object, blocking harmful substances such as oxygen, moisture, and microorganisms in the external environment, thereby playing an anti-corrosion role. Vanillin is added in the present invention, which can further inhibit the corrosion of the aluminum profile. Specific embodiments

[0012] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0013] Example 1: A preparation process of an aluminum profile for a high-life mold, comprising the following steps: Step 1: Preparation of an aluminum profile with a zirconated film on the surface: Prepare the following raw materials according to the ratio, by weight percentage: 0.60 wt% Si, 0.22 wt% Cu, 0.13 wt% Mn, 0.90 wt% Mg, 0.07 wt% Cr, 0.015 wt% Ti, 0.2 wt% Fe, and the balance is Al; wherein, the total unavoidable impurities contained in each raw material are ≤ 0.1%; Melt the raw materials, skim the slag, refine, stand, filter, and cast to obtain an aluminum alloy ingot, and then perform homogenization treatment; put it into a mold, extrude and cool to 30 °C, perform straightening treatment, and keep warm for 4.5 h to obtain an aluminum substrate; then perform alkali washing, acid washing, and drying on the aluminum substrate, and wash with deionized water to obtain a pretreated aluminum substrate; Put the pretreated aluminum substrate into a zirconium conversion solution for treatment for 35 min, wash and dry to obtain an aluminum profile with a zirconated film on the surface; The zirconium conversion solution uses deionized water as a solvent and includes the following components: 16 g / L of sodium dihydrogen phosphate, 5 g / L of 3-glycidoxypropyltriethoxysilane, 6 g / L of sodium fluoride, 0.5 g / L of zirconium fluoric acid, and 1.5 ml / L of phosphoric acid; Step 2: Preparation of MOF material: Take 0.3 g of 1,3,5-benzenetricarboxylic acid and 15 mL of N,N-dimethylformamide solution, stir evenly to obtain 1,3,5-benzenetricarboxylic acid solution; take 2.3 g of ammonium cerium nitrate and 8 mL of deionized water, stir evenly to obtain ammonium cerium nitrate, add 2.6 mL of formic acid solution, stir evenly, add the solution to 1,3,5-benzenetricarboxylic acid solution, mix evenly, heat up to 100 °C, react for 18 min, centrifuge, wash, and dry to obtain MOF material; Step 3: Preparation of corrosion-resistant chitosan microcapsules: Take 0.4 g of chitosan and 40 mL of acetic acid, stir evenly to obtain chitosan acetate solution; take 0.35 g of vanillin and chitosan acetate solution, stir evenly to obtain aqueous phase; take 50 mL of petroleum ether and 50 mL of liquid paraffin, stir evenly, add 8 mL of Span 80 and 8 mL of Tween 20, stir evenly to obtain oil phase; under shear stirring, drop the aqueous phase into the oil phase, emulsify for 18 min, drop 20 mL of glutaraldehyde, solidify, centrifuge, wash, and dry to obtain corrosion-resistant chitosan microcapsules; Step 4: Preparation of chitosan-MOF composite material: Take 2.2 g of corrosion-resistant chitosan microcapsules and 100 mL of ethanol, stir evenly, add 0.4 g of MOF material, stir for 7.5 h, centrifuge, wash, and dry to obtain chitosan-MOF composite material; Step 5: Preparation of aluminum profiles for high-life molds: Coat the surface of the aluminum profile with a zirconium conversion film with a corrosion inhibitor solution, and the coating thickness is 2 µm, then dry to obtain aluminum profiles for high-life molds; The corrosion inhibitor solution is composed of the following components by weight: 4.3 parts of sodium fluoride, 5.5 parts of chitosan-MOF composite material, 3.8 parts of fluotitanate, 2.8 parts of triethanolamine, 2.8 parts of zinc phosphate, 2.4 parts of potassium permanganate, 1.7 parts of sodium molybdate, 1.6 parts of ethylenediaminetetraacetic acid, 1.5 parts of malic acid, 1.3 parts of sodium dodecylbenzenesulfonate, 1.3 parts of nickel sulfate, and 95 parts of deionized water.

[0014] Example 2: A preparation process of aluminum profiles for high-life molds, including the following steps: Step 1: Preparation of aluminum profiles with a zirconium conversion film on the surface: Prepare the following raw materials according to the ratio, by weight percentage: 0.55 wt% Si, 0.2 wt% Cu, 0.1 wt% Mn, 0.85 wt% Mg, 0.06 wt% Cr, 0.01 wt% Ti, 0.1 wt% Fe, and the balance is Al; among them, the total unavoidable impurities contained in each raw material ≤ 0.1%; The raw materials are melted, slagged, refined, statically cast, filtered, and cast to obtain an aluminum alloy ingot, which is then subjected to homogenization treatment; it is placed in a mold, extruded into shape, cooled to 30 °C, straightened, and kept warm for 4 h to obtain an aluminum substrate; then the aluminum substrate is alkali-washed, pickled, dried, and washed with deionized water to obtain a pretreated aluminum substrate; The pretreated aluminum substrate is placed in a zirconium conversion solution for 30 min, washed, and dried to obtain an aluminum profile with a zirconium film on its surface; The zirconium conversion solution uses deionized water as a solvent and includes the following components: 15 g / L of sodium dihydrogen phosphate, 4 g / L of 3-glycidoxypropyltriethoxysilane, 5 g / L of sodium fluoride, 0.4 g / L of zirconium fluoric acid, and 1 ml / L of phosphoric acid; Step 2: Preparation of MOF material: Take 0.3 g of 1,3,5-benzenetricarboxylic acid and 15 mL of N,N-dimethylformamide solution, stir evenly to obtain a 1,3,5-benzenetricarboxylic acid solution; take 2.3 g of ammonium cerium(IV) nitrate and 8 mL of deionized water, stir evenly to obtain ammonium cerium(IV) nitrate, add 2.6 mL of formic acid solution, stir evenly, add the solution to the 1,3,5-benzenetricarboxylic acid solution, mix evenly, heat up to 100 °C, react for 15 min, centrifuge, wash, and dry to obtain the MOF material; Step 3: Preparation of corrosion-resistant chitosan microcapsules: Take 0.4 g of chitosan and 40 mL of acetic acid, stir evenly to obtain a chitosan acetate solution; take 0.35 g of vanillin and the chitosan acetate solution, stir evenly to obtain an aqueous phase; take 50 mL of petroleum ether and 50 mL of liquid paraffin, stir evenly, add 8 mL of Span 80 and 8 mL of Tween 20, stir evenly to obtain an oil phase; under shear stirring, drop the aqueous phase into the oil phase, emulsify for 15 min, drop 20 mL of glutaraldehyde, solidify, centrifuge, wash, and dry to obtain corrosion-resistant chitosan microcapsules; Step 4: Preparation of chitosan-MOF composite material: Take 2.2 g of corrosion-resistant chitosan microcapsules and 100 mL of ethanol, stir evenly, add 0.4 g of MOF material, stir for 7 h, centrifuge, wash, and dry to obtain a chitosan-MOF composite material; Step 5: Preparation of aluminum profile for high-life molds: Coat the corrosion prevention liquid on the surface of the aluminum profile with a zirconium film on its surface, with a coating thickness of 2 µm, and dry to obtain an aluminum profile for high-life molds; The anti-corrosion liquid consists of the following components by weight: 4 parts of sodium fluoride, 5 parts of chitosan-MOF composite material, 3.5 parts of fluorotitanate, 2.5 parts of triethanolamine, 2.5 parts of zinc phosphate, 2.2 parts of potassium permanganate, 1.5 parts of sodium molybdate, 1.5 parts of ethylenediaminetetraacetic acid, 1.2 parts of malic acid, 1.2 parts of sodium dodecylbenzenesulfonate, 1.2 parts of nickel sulfate, and 90 parts of deionized water.

[0015] Example 3: A preparation process of aluminum profiles for high-life molds, comprising the following steps: Step 1: Preparation of aluminum profiles with a zirconium conversion film on the surface: Prepare the following raw materials according to the ratio, by weight percentage: 0.65wt% Si, 0.25wt% Cu, 0.15wt% Mn, 0.92wt% Mg, 0.08wt% Cr, 0.02wt% Ti, 0.25wt% Fe, and the balance is Al; among them, the total unavoidable impurities contained in each raw material are ≤0.1%. Melt the raw materials, skim the slag, refine, stand, filter, and cast to obtain an aluminum alloy ingot, and then perform homogenization treatment; put it into a mold, extrude and cool to 30°C, perform straightening treatment, and keep warm for 5h to obtain an aluminum substrate; then perform alkali washing, acid washing, and drying on the aluminum substrate, and wash with deionized water to obtain a pretreated aluminum substrate. Put the pretreated aluminum substrate into a zirconium conversion solution for treatment for 40 min, wash and dry to obtain aluminum profiles with a zirconium conversion film on the surface. The zirconium conversion solution uses deionized water as a solvent and includes the following components: 17 g / L of sodium dihydrogen phosphate, 6 g / L of 3-glycidoxypropyltriethoxysilane, 7 g / L of sodium fluoride, 0.6 g / L of fluoziric acid, and 2 ml / L of phosphoric acid. Step 2: Preparation of MOF material: Take 0.3 g of 1,3,5-benzenetricarboxylic acid and 15 mL of N,N-dimethylformamide solution, stir evenly to obtain a 1,3,5-benzenetricarboxylic acid solution; stir 2.3 g of ammonium cerium(IV) nitrate and 8 mL of deionized water evenly to obtain ammonium cerium(IV) nitrate, add 2.6 mL of formic acid solution, stir evenly, add the solution to the 1,3,5-benzenetricarboxylic acid solution, mix evenly, heat up to 100°C, react for 20 min, centrifuge, wash, and dry to obtain the MOF material. Step 3: Preparation of corrosion-resistant chitosan microcapsules: Take 0.4 g of chitosan and 40 mL of acetic acid, stir evenly to obtain a chitosan acetate solution; take 0.35 g of vanillin and the chitosan acetate solution, stir evenly to obtain an aqueous phase; take 50 mL of petroleum ether and 50 mL of liquid paraffin, stir evenly, add 8 mL of Span 80 and 8 mL of Tween 20, stir evenly to obtain an oil phase; under shear stirring, drop the aqueous phase into the oil phase, emulsify for 20 min, drop 20 mL of glutaraldehyde, solidify, centrifuge, wash, and dry to obtain corrosion-resistant chitosan microcapsules; Step 4: Preparation of chitosan-MOF composite material: Take 2.2 g of corrosion-resistant chitosan microcapsules and 100 mL of ethanol, stir evenly, add 0.4 g of MOF material, stir for 8 h, centrifuge, wash, and dry to obtain a chitosan-MOF composite material; Step 5: Preparation of aluminum profiles for high-life molds: Coat the anticorrosion liquid on the surface of the aluminum profile with a zirconium conversion film, the coating thickness is 2 µm, dry to obtain aluminum profiles for high-life molds; The anticorrosion liquid is composed of the following components, by weight: 4.5 parts of sodium fluoride, 6 parts of chitosan-MOF composite material, 4 parts of fluorotitanate, 3 parts of triethanolamine, 3 parts of zinc phosphate, 2.6 parts of potassium permanganate, 2 parts of sodium molybdate, 1.7 parts of ethylenediaminetetraacetic acid, 1.7 parts of malic acid, 1.5 parts of sodium dodecylbenzenesulfonate, 1.5 parts of nickel sulfate, and 100 parts of deionized water.

[0016] Comparative Example 1: Do not add 3-glycidoxypropyltriethoxysilane to the zirconium conversion solution, and the rest is the same as in Example 1: Step 1: Preparation of aluminum profiles with a zirconium conversion film on the surface: Prepare the following raw materials according to the ratio, by weight percentage: 0.60 wt% Si, 0.22 wt% Cu, 0.13 wt% Mn, 0.90 wt% Mg, 0.07 wt% Cr, 0.015 wt% Ti, 0.2 wt% Fe, and the balance is Al; among them, the total unavoidable impurities contained in each raw material are ≤0.1%; Melt the raw materials, skim the slag, refine, stand, filter, and cast to obtain an aluminum alloy ingot, and then perform homogenization treatment; put it into a mold, extrude and form, cool to 30 °C, perform straightening treatment, and keep warm for 4.5 h to obtain an aluminum substrate; then perform alkali washing, acid washing, and drying on the aluminum substrate, and wash with deionized water to obtain a pretreated aluminum substrate; Put the pretreated aluminum substrate into the zirconium conversion solution for treatment for 35 min, wash and dry to obtain aluminum profiles with a zirconium conversion film on the surface; The zirconium conversion solution uses deionized water as a solvent and includes the following components: 16 g / L of sodium dihydrogen phosphate, 6 g / L of sodium fluoride, 0.5 g / L of zirconium fluoroacid, and 1.5 ml / L of phosphoric acid; Step 2: Preparation of the MOF material: Take 0.3 g of 1,3,5-benzenetricarboxylic acid and 15 mL of N,N-dimethylformamide solution, stir evenly to obtain a 1,3,5-benzenetricarboxylic acid solution; take 2.3 g of ammonium cerium nitrate and 8 mL of deionized water, stir evenly to obtain ammonium cerium nitrate, add 2.6 mL of formic acid solution, stir evenly, add the solution to the 1,3,5-benzenetricarboxylic acid solution, mix evenly, heat up to 100 °C, react for 18 min, centrifuge, wash, and dry to obtain the MOF material; Step 3: Preparation of the corrosion-resistant chitosan microcapsules: Take 0.4 g of chitosan and 40 mL of acetic acid, stir evenly to obtain a chitosan acetate solution; take 0.35 g of vanillin and the chitosan acetate solution, stir evenly to obtain the aqueous phase; take 50 mL of petroleum ether and 50 mL of liquid paraffin, stir evenly, add 8 mL of Span 80 and 8 mL of Tween 20, stir evenly to obtain the oil phase; under shear stirring, drop the aqueous phase into the oil phase, emulsify for 18 min, drop 20 mL of glutaraldehyde, solidify, centrifuge, wash, and dry to obtain the corrosion-resistant chitosan microcapsules; Step 4: Preparation of the chitosan-MOF composite material: Take 2.2 g of the corrosion-resistant chitosan microcapsules and 100 mL of ethanol, stir evenly, add 0.4 g of the MOF material, stir for 7.5 h, centrifuge, wash, and dry to obtain the chitosan-MOF composite material; Step 5: Preparation of the aluminum profile for high-life molds: Coat the corrosion prevention liquid on the surface of the aluminum profile with a zirconium conversion film, and the coating thickness is 2 µm, then dry to obtain the aluminum profile for high-life molds; The corrosion prevention liquid is composed of the following components by weight: 4.3 parts of sodium fluoride, 5.5 parts of the chitosan-MOF composite material, 3.8 parts of fluoro-titanate, 2.8 parts of triethanolamine, 2.8 parts of zinc phosphate, 2.4 parts of potassium permanganate, 1.7 parts of sodium molybdate, 1.6 parts of ethylenediaminetetraacetic acid, 1.5 parts of malic acid, 1.3 parts of sodium dodecylbenzenesulfonate, 1.3 parts of nickel sulfate, and 95 parts of deionized water.

[0017] Comparative Example 2: Without adding the chitosan-MOF composite material, the rest is the same as in Example 1: Step 1: Preparation of the aluminum profile with a zirconium conversion film on the surface: Prepare the following raw materials in proportion, by weight percentage: 0.60 wt% Si, 0.22 wt% Cu, 0.13 wt% Mn, 0.90 wt% Mg, 0.07 wt% Cr, 0.015 wt% Ti, 0.2 wt% Fe, with the balance being Al; wherein, the total unavoidable impurities contained in each raw material are ≤ 0.1%; Melt the raw materials, remove slag, refine, let stand, filter, and cast to obtain an aluminum alloy ingot, then perform homogenization treatment; place it in a mold, extrude and form, cool to 30 °C, perform straightening treatment, and keep warm for 4.5 h to obtain an aluminum substrate; then perform alkali washing, acid washing, and drying on the aluminum substrate, and wash with deionized water to obtain a pretreated aluminum substrate; Place the pretreated aluminum substrate into a zirconium conversion solution for treatment for 35 min, wash and dry to obtain an aluminum profile with a zirconium film on its surface; The zirconium conversion solution uses deionized water as a solvent and includes the following components: 16 g / L of sodium dihydrogen phosphate, 5 g / L of 3-glycidoxypropyltriethoxysilane, 6 g / L of sodium fluoride, 0.5 g / L of zirconium fluoroacid, 1.5 ml / L of phosphoric acid; Step 2: Preparation of the aluminum profile for high-life molds: Coat the aluminum profile with a zirconium film on its surface with an anticorrosive solution, with a coating thickness of 2 µm, and dry to obtain an aluminum profile for high-life molds; The anticorrosive solution is composed of the following components, by weight parts: 4.3 parts of sodium fluoride, 3.8 parts of fluotitanate, 2.8 parts of triethanolamine, 2.8 parts of zinc phosphate, 2.4 parts of potassium permanganate, 1.7 parts of sodium molybdate, 1.6 parts of ethylenediaminetetraacetic acid, 1.5 parts of malic acid, 1.3 parts of sodium dodecylbenzenesulfonate, 1.3 parts of nickel sulfate, 95 parts of deionized water.

[0018] Comparative Example 3: Without adding corrosion-resistant chitosan microcapsules, the rest is the same as in Example 1: Step 1: Preparation of the aluminum profile with a zirconium film on its surface: Prepare the following raw materials in proportion, by weight percentage: 0.60 wt% Si, 0.22 wt% Cu, 0.13 wt% Mn, 0.90 wt% Mg, 0.07 wt% Cr, 0.015 wt% Ti, 0.2 wt% Fe, with the balance being Al; wherein, the total unavoidable impurities contained in each raw material are ≤ 0.1%; Melt the raw materials, remove slag, refine, let stand, filter, and cast to obtain an aluminum alloy ingot, then perform homogenization treatment; place it in a mold, extrude and form, cool to 30 °C, perform straightening treatment, and keep warm for 4.5 h to obtain an aluminum substrate; then perform alkali washing, acid washing, and drying on the aluminum substrate, and wash with deionized water to obtain a pretreated aluminum substrate; The pretreated aluminum substrate is placed in a zirconium conversion solution for 35 minutes, washed and dried to obtain an aluminum profile with a zirconium film on its surface; The zirconium conversion solution uses deionized water as a solvent and includes the following components: 16 g / L of sodium dihydrogen phosphate, 5 g / L of 3-glycidoxypropyltriethoxysilane, 6 g / L of sodium fluoride, 0.5 g / L of zirconium fluoroformic acid, and 1.5 ml / L of phosphoric acid; Step 2: Preparation of the MOF material: Take 0.3 g of 1,3,5-benzenetricarboxylic acid and 15 mL of N,N-dimethylformamide solution, stir evenly to obtain a 1,3,5-benzenetricarboxylic acid solution; mix 2.3 g of ammonium cerium nitrate and 8 mL of deionized water, stir evenly to obtain ammonium cerium nitrate, add 2.6 mL of formic acid solution, stir evenly, add the solution to the 1,3,5-benzenetricarboxylic acid solution, mix evenly, heat up to 100 °C, react for 18 minutes, centrifuge, wash and dry to obtain the MOF material; Step 3: Preparation of the aluminum profile for high-life molds: Coat the anti-corrosion solution on the surface of the aluminum profile with a zirconium film on its surface, with a coating thickness of 2 µm, and dry to obtain an aluminum profile for high-life molds; The anti-corrosion solution is composed of the following components, by weight: 4.3 parts of sodium fluoride, 5.5 parts of MOF material, 3.8 parts of fluorotitanate, 2.8 parts of triethanolamine, 2.8 parts of zinc phosphate, 2.4 parts of potassium permanganate, 1.7 parts of sodium molybdate, 1.6 parts of ethylenediaminetetraacetic acid, 1.5 parts of malic acid, 1.3 parts of sodium dodecylbenzenesulfonate, 1.3 parts of nickel sulfate, and 95 parts of deionized water.

[0019] Comparative Example 4: Do not load a zirconium film on the surface of the aluminum profile, and the rest is the same as in Example 1: Step 1: Preparation of the pretreated aluminum substrate: Prepare the following raw materials according to the ratio, by weight percentage: 0.60 wt% Si, 0.22 wt% Cu, 0.13 wt% Mn, 0.90 wt% Mg, 0.07 wt% Cr, 0.015 wt% Ti, 0.2 wt% Fe, and the balance is Al; among them, the total unavoidable impurities contained in each raw material are ≤ 0.1%; Melt the raw materials, remove slag, refine, stand, filter, and cast to obtain an aluminum alloy ingot, and then perform homogenization treatment; place it in a mold, extrude, cool to 30 °C, perform straightening treatment, and keep warm for 4.5 h to obtain an aluminum substrate; then perform alkali washing, acid washing, and drying on the aluminum substrate, and wash with deionized water to obtain the pretreated aluminum substrate; Step 2: Preparation of the MOF material: Take 0.3 g of 1,3,5-benzenetricarboxylic acid and 15 mL of N,N-dimethylformamide solution, stir evenly to obtain a 1,3,5-benzenetricarboxylic acid solution; take 2.3 g of ammonium cerium nitrate and 8 mL of deionized water, stir evenly to obtain ammonium cerium nitrate, add 2.6 mL of formic acid solution, stir evenly, add the solution to the 1,3,5-benzenetricarboxylic acid solution, mix evenly, heat up to 100 °C, react for 18 min, centrifuge, wash, and dry to obtain the MOF material; Step 3: Preparation of corrosion-resistant chitosan microcapsules: Take 0.4 g of chitosan and 40 mL of acetic acid, stir evenly to obtain a chitosan acetate solution; take 0.35 g of vanillin and the chitosan acetate solution, stir evenly to obtain the aqueous phase; take 50 mL of petroleum ether and 50 mL of liquid paraffin, stir evenly, add 8 mL of Span 80 and 8 mL of Tween 20, stir evenly to obtain the oil phase; under shear stirring, drop the aqueous phase into the oil phase, emulsify for 18 min, drop 20 mL of glutaraldehyde, solidify, centrifuge, wash, and dry to obtain corrosion-resistant chitosan microcapsules; Step 4: Preparation of chitosan-MOF composite material: Take 2.2 g of corrosion-resistant chitosan microcapsules and 100 mL of ethanol, stir evenly, add 0.4 g of MOF material, stir for 7.5 h, centrifuge, wash, and dry to obtain the chitosan-MOF composite material; Step 5: Preparation of aluminum profiles for high-life molds: Coat the anti-corrosion liquid on the surface of the aluminum profile with a zirconium conversion film, and the coating thickness is 2 µm, then dry to obtain the aluminum profile for high-life molds; The anti-corrosion liquid is composed of the following components by weight: 4.3 parts of sodium fluoride, 5.5 parts of chitosan-MOF composite material, 3.8 parts of fluotitanate, 2.8 parts of triethanolamine, 2.8 parts of zinc phosphate, 2.4 parts of potassium permanganate, 1.7 parts of sodium molybdate, 1.6 parts of ethylenediaminetetraacetic acid, 1.5 parts of malic acid, 1.3 parts of sodium dodecylbenzenesulfonate, 1.3 parts of nickel sulfate, and 95 parts of deionized water.

[0020] Experiment: Take the aluminum profiles for life molds prepared in Examples 1 - 3 and Comparative Examples 1 - 4 for performance testing. Refer to the ASTM-D1654 scratch test standard to evenly draw an "X" shape mark on the surface of the high-hardness and corrosion-resistant nuts prepared in the examples and comparative examples. Immerse the scratched specimens in a 3 wt% NaCl solution for several hours, then take them out and observe the corrosion morphology at the scratched areas. The data obtained are shown in Table 1 below: Table 1

[0021] Conclusion: It can be seen from the data comparison in the table that in Comparative Example 1, 3-glycidoxypropyltriethoxysilane is not added to the zirconium conversion solution, and the combination of the zirconium conversion film and the anti-corrosion coating part is not tight. When there is a scratch treatment, the aluminum profile for life molds corrodes at the scratch at 1368 h, and the coating peels off. In Comparative Example 2, the chitosan-MOF composite material is not added, and the aluminum profile for life molds is prone to corrosion. Corrosion appears at the scratch at 1284 h, and the coating peels off. In Comparative Example 3, the corrosion-resistant chitosan microcapsules are not added, and the combination of the zirconium conversion film and the anti-corrosion coating part is not tight. Corrosion appears at the scratch at 1332 h. In Comparative Example 4, the zirconium conversion film is not loaded on the surface of the aluminum profile, and the aluminum profile for life molds is prone to corrosion. Corrosion appears at the scratch at 1326 h, and the coating peels off. In Examples 1-3 of the present invention, the zirconium conversion film is loaded on the surface of the aluminum profile. The zirconium conversion film generates an oxide layer on the surface of the aluminum substrate through a hydrolysis reaction, filling the micropores on the surface of the aluminum matrix and enhancing the corrosion resistance of the aluminum profile. Then, the anti-corrosion liquid is coated on the surface of the aluminum profile with the zirconium conversion film, further enhancing the corrosion resistance of the aluminum profile. In the present invention, 3-glycidoxypropyltriethoxysilane is added to the zirconium conversion solution, so that the surface of the zirconium conversion film has epoxy groups. The epoxy groups on the surface of the zirconium conversion film form hydrogen bonds and coordination bonds with the amino groups in the corrosion-resistant chitosan microcapsules, improving the bonding strength of the anti-corrosion coating, thereby improving the corrosion resistance of the aluminum profile for molds. Chitosan has good film-forming properties and can form a dense protective film on the surface of an object, blocking harmful substances such as oxygen, moisture, and microorganisms in the external environment, thereby playing an anti-corrosion role. Vanillin is added in the present invention, which can further inhibit the corrosion of the aluminum profile. Therefore, the aluminum profile for life molds prepared by the present invention has good corrosion resistance and a long service life. At 1440 h, there is no corrosion at the scratch and the coating is intact.

[0022] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, in any regard, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, it is intended to embrace all changes falling within the meaning and scope of the equivalent elements of the claims in the present invention.

Claims

1. A process for preparing aluminum profiles for long-life molds, characterized in that: The following steps are involved: Step 1: Prepare the following raw materials in proportion, by weight percentage: 0.55wt%-0.65wt% Si, 0.2wt%-0.25wt% Cu, 0.1wt%-0.15wt% Mn, 0.85wt%-0.92wt% Mg, 0.06wt%-0.08wt% Cr, 0.01wt%-0.02wt% Ti, 0.1wt%-0.25wt% Fe, and the balance is Al; wherein the total amount of unavoidable impurities contained in each raw material is ≤0.1%; Step 2: Melting the raw materials, slagging, refining, standing, filtering, casting to obtain aluminum alloy ingots, and then homogenizing them; putting them into a mold, extruding them, cooling them to 25-35°C, straightening them, and keeping them warm for 4-5 hours to obtain an aluminum substrate; then alkali washing, acid washing, drying the aluminum substrate, and washing them with deionized water to obtain a pretreated aluminum substrate; Step 3: Place the pretreated aluminum substrate into the zirconium conversion solution for 30-40 minutes, wash and dry to obtain an aluminum profile with a zirconium film on the surface; apply the anti-corrosion liquid on the surface of the aluminum profile with the zirconium film on the surface, dry, and obtain an aluminum profile for a long-life mold; The zirconium conversion solution uses deionized water as a solvent and includes the following components: 15-17 g / L of sodium dihydrogen phosphate, 4-6 g / L of 3-glycidoxypropyltriethoxysilane, 5-7 g / L of sodium fluoride, 0.4-0.6 g / L of fluorozirconic acid, and 1-2 ml / L of phosphoric acid; The anti-corrosion liquid is composed of the following components, calculated by weight: 4-4.5 parts of sodium fluoride, 5-6 parts of chitosan-MOF composite material, 3.5-4 parts of fluorotitanate, 2.5-3 parts of triethanolamine, 2.5-3 parts of zinc phosphate, 2.2-2.6 parts of potassium permanganate, 1.5-2 parts of sodium molybdate, 1.5-1.7 parts of ethylenediaminetetraacetic acid, 1.2-1.7 parts of malic acid, 1.2-1.5 parts of sodium dodecylbenzene sulfate, 1.2-1.5 parts of nickel sulfate, and 90-100 parts of deionized water.

2. The process for preparing an aluminum profile for a long-life mold according to claim 1, characterized in that: The preparation method of the chitosan-MOF composite material is as follows: taking corrosion-resistant chitosan microcapsules and ethanol, stirring evenly, adding MOF material, stirring for 7-8 hours, centrifuging, washing, and drying to obtain the chitosan-MOF composite material.

3. The process for preparing an aluminum profile for a long-life mold according to claim 2, characterized in that: The preparation method of the MOF material is as follows: taking 1,3,5-trimellitic acid and N,N-dimethylformamide solution, stirring evenly to obtain 1,3,5-trimellitic acid solution; adding cerium ammonium nitrate and deionized water, stirring evenly to obtain cerium ammonium nitrate, adding formic acid solution, stirring evenly, adding the solution to the 1,3,5-trimellitic acid solution, mixing evenly, heating to 100°C, reacting for 15-20 minutes, centrifuging, washing, and drying to obtain the MOF material.

4. The process for preparing an aluminum profile for a long-life mold according to claim 2, characterized in that: The preparation method of the corrosion-resistant chitosan microcapsule comprises the following steps: taking chitosan and acetic acid, stirring evenly to obtain a chitosan acetic acid solution; taking vanillin and chitosan acetic acid solution, stirring evenly to obtain a water phase; taking petroleum ether and liquid paraffin, stirring evenly, adding Span 80 and Tween 20, stirring evenly to obtain an oil phase; under shear stirring, dropping the water phase into the oil phase, emulsifying for 15-20 minutes, dropping glutaraldehyde, solidifying, centrifuging, washing, and drying to obtain the corrosion-resistant chitosan microcapsule.

5. The process for preparing an aluminum profile for a long-life mold according to claim 2, characterized in that: The mass ratio of the corrosion-resistant chitosan microcapsule to the MOF material is 2.2:(0.3-0.5).

6. An aluminum profile for molds with a long service life prepared according to the process for preparing an aluminum profile for molds with a long service life as described in any one of claims 1 to 5.

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