High-strength anti-cracking aluminum wheel and preparation method thereof

Abstract

The invention discloses a high-strength anti-cracking aluminum wheel and a preparation method thereof, and relates to the technical field of metal coatings. The method comprises the steps that 1, an aluminum alloy wheel is subjected to alkali washing, acid washing, water washing and blow-drying, and a pretreated aluminum wheel is obtained; 2, the pretreated aluminum wheel is placed in zinc liquid for primary zincing, transferred into a nitric acid solution to be soaked, placed in the zinc liquid again for secondary zincing, washed with water and blow-dried, a zinc layer is formed, and the aluminum wheel is marked as an aluminum wheel A; 3, the aluminum wheel A is placed in a first nickel-phosphorus solution for primary electro-deposition and transferred into a second nickel-phosphorus solution for secondary electro-deposition, washing and blow-drying are carried out, and a nickel-phosphorus layer is formed; and the high-strength anti-cracking aluminum wheel is obtained. The prepared high-strength anti-cracking aluminum wheel has excellent mechanical performance and durability, and is suitable for high-load and high-corrosion application environments.

Description

Technical Field

[0001] The present invention relates to the technical field of metal plating, and specifically to a high-strength anti-cracking aluminum wheel and a preparation method thereof. Background Art

[0002] In recent years, with the development trend of lightweight wheels. Aluminum alloy wheels have gradually replaced traditional steel wheels due to their advantages such as lightweight and good heat dissipation. Their penetration rate has exceeded 80% and they are widely used in the automotive industry. However, traditional aluminum alloy wheels have certain limitations; their surfaces are easily scratched during long-term use and their durability is poor; and their corrosion resistance is insufficient, so it is necessary to further improve their performance.

[0003] In the prior art, a coating is usually applied on the surface of an aluminum alloy wheel to improve the surface strength and corrosion resistance. However, the existing coatings have the following disadvantages: First, the internal stress in the coating is large, which easily generates microcracks, resulting in an increased risk of cracking. Second, generally a single electroplating is used to improve corrosion resistance, but the bonding force between the coating and the substrate is insufficient, the coating surface is non-uniform, the coating strength is not high, and the coating density needs to be improved, making it difficult to meet the requirements of high strength and high durability.

[0004] In summary, to solve the above problems, it is of great significance to prepare a high-strength anti-cracking aluminum wheel. Summary of the Invention

[0005] The purpose of the present invention is to provide a high-strength anti-cracking aluminum wheel and a preparation method thereof to solve the problems raised in the above background art.

[0006] To solve the above technical problems, the present invention provides the following technical solutions: A preparation method of a high-strength anti-cracking aluminum wheel, comprising the following steps: Step 1: Alkaline wash, acid wash, and water wash and dry an aluminum alloy wheel to obtain a pretreated aluminum wheel; Step 2: Immerse the pretreated aluminum wheel in zinc solution for primary zincification, transfer it to a nitric acid solution for soaking, then immerse it in zinc solution again for secondary zincification, and water wash and dry to form a zinc layer, denoted as aluminum wheel A; Step 3: Immerse aluminum wheel A in a first nickel-phosphorus solution for primary electrodeposition, transfer it to a second nickel-phosphorus solution for secondary electrodeposition, and water wash and dry to form a nickel-phosphorus layer; thus obtaining a high-strength anti-cracking aluminum wheel.

[0007] Preferably, the zinc solution comprises the following components: 0.6 - 1 g / L zinc chloride, 0.01 - 0.012 g / L ferric chloride, 0.02 - 0.05 g / L copper sulfate, 3.5 - 4 g / L sodium hydroxide, 0.05 - 0.1 g / L sodium tartrate, 0.08 - 0.1 g / L sodium dodecylbenzenesulfonate, 0.01 - 0.02 g / L polyethylene glycol, and the rest is deionized water.

[0008] Preferably, the process parameters for the first zincification are as follows: soaking at room temperature for 10 to 15 seconds; the concentration of the nitric acid solution is 40 to 50 wt% nitric acid aqueous solution, and the soaking time is 5 to 15 seconds; the process parameters for the second zincification are: soaking at room temperature for 1 to 3 minutes.

[0009] Preferably, 20 to 30 g / L nickel chloride, 15 to 25 g / L nickel sulfate, 15 to 18 g / L sodium hypophosphite, 20 to 25 g / L trisodium citrate, 40 to 45 g / L ammonium chloride, 1.5 to 2.5 g / L modified nano silicon carbide, 0.05 to 0.1 g / L sodium dodecylbenzenesulfonate; adjust the pH to 4.5 to 5.5; The second nickel-phosphorus solution comprises the following components: 20 to 25 g / L nickel chloride, 25 to 35 g / L nickel sulfate, 18 to 22 g / L sodium hypophosphite, 0.1 to 0.2 g / L thiourea, 25 to 30 g / L trisodium citrate, 40 to 45 g / L ammonium chloride, 1.5 to 2.5 g / L modified nano alumina, 0.05 to 0.1 g / L sodium dodecyl sulfate; adjust the pH to 4.5 to 5.5.

[0010] Preferably, the process parameters for the first electro-deposition are as follows: the applied magnetic field is 0.05 to 0.1 T, the temperature is 85 to 90 °C, the stirring speed is 100 to 300 rpm, the current density is 3 to 4 A / dm2, and the electro-deposition time is 35 to 40 minutes.

[0011] Preferably, the process parameters for the second electro-deposition are as follows: the applied magnetic field is 0.12 to 0.14 T, the temperature is 85 to 90 °C, the stirring speed is 100 to 300 rpm, the current density is 2 to 3 A / dm2, and the electro-deposition time is 20 to 25 minutes.

[0012] Preferably, the preparation processes of the modified nano silicon carbide and the modified nano alumina are the same; they include the following steps: S1-1: Add polyethylene glycol monoallyl ether and 2-mercaptonicotinic acid with a molar ratio of 1:1 to DMF, and add a photoinitiator; under nitrogen atmosphere at room temperature, irradiate with ultraviolet light for 2 to 4 hours, wash with ether, and remove the solvent to obtain a modifier; S1-2: Add nano silicon carbide or nano alumina to deionized water, add the modifier and disperse evenly, adjust the pH to 7.5 to 8, stir at room temperature for 6 to 12 hours, centrifuge and wash, and dry to obtain modified nano silicon carbide or modified nano alumina.

[0013] Preferably, the alkaline solution for alkaline washing comprises the following components: 50-60 g / L of sodium hydroxide, 1.5-1.8 g / L of sodium dodecylbenzenesulfonate, 0.1-0.2 g / L of polyethylene glycol, and the rest is deionized water; the process parameters for alkaline washing are: alkaline washing at room temperature for 15-60 seconds; The acid solution for acid washing comprises the following components: 25-30 wt% of hydrofluoric acid, 30-35 wt% of nitric acid, and the rest is deionized water; the process parameters for acid washing are: acid washing at room temperature for 10-60 seconds.

[0014] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: in this application, through two zincification treatments in a specific zinc solution, and combined with a double-layer electrodeposited nickel-phosphorus layer of the first nickel-phosphorus solution and the second nickel-phosphorus solution, the bonding property between the coating and the aluminum wheel is effectively guaranteed. On the basis of ensuring the high strength and crack resistance of the aluminum wheel, its wear resistance and corrosion resistance are effectively improved.

[0015] Among them, the same zinc solution is used for the two zincification treatments. One is preliminary zincification, and the second zincification is carried out after immersion treatment with a nitric acid solution. In this process, on the one hand, due to the uniformity of the zinc solution before and after zincification, on the other hand, copper ions are introduced into the zinc solution, which can inhibit the dissolution of aluminum during the nitric acid solution treatment and promote the uniform deposition during the second zincification process. Since the surface roughness increases after the first zincification is removed by nitric acid, the second zincification process has more nucleation sites, resulting in a more uniform and finer-grained zinc deposition layer, inhibiting the formation of pores or deep pits. In this way, the surface quality of the zinc layer is guaranteed, laying a good foundation for the subsequent plating of the nickel-phosphorus layer, promoting the bonding of the nickel-phosphorus layer, reducing the surface defects of the nickel-phosphorus layer, and improving the crack resistance and corrosion resistance of the aluminum wheel.

[0016] Among them, the first nickel-phosphorus solution and the second nickel-phosphorus solution are formed by controlling nickel chloride, nickel sulfate, and the types of nanoparticles (nano-aluminum oxide, nano-silicon carbide), and a double-layer electrodeposited nickel-phosphorus layer is effectively formed by setting a specific order and a specific magnetic field. The bonding force with the zinc layer is effectively guaranteed, making the coating dense and uniform, reducing coating defects, and inhibiting crack generation. First, compared with a single nickel-phosphorus plating solution, double-layer plating is beneficial to produce a denser and more regular nickel-phosphorus layer, thereby effectively controlling the crack resistance and increasing the surface hardness and corrosion resistance. Second, the proportions of nickel chloride and nickel sulfate in the two nickel-phosphorus solutions of the first nickel-phosphorus solution and the second nickel-phosphorus solution are different. The reason is that in order to refine the grains and improve the plating uniformity of the nickel-phosphorus layer, different magnetic fields are set during the two plating processes. The magnetic field will affect the convection of the plating solution, reduce concentration polarization, and improve the deposition uniformity. However, nickel sulfate will affect the viscosity of the plating solution and nickel chloride will affect the conductivity, and the hydrogen evolution needs to be balanced; therefore, the proportion of nickel types needs to be set correspondingly to ensure the comprehensive performance of the double-layer plated nickel-phosphorus layer. Third, compared with depositing nano-aluminum oxide first and then nano-silicon carbide, depositing nano-silicon carbide first and depositing nano-aluminum oxide on the outermost layer has better load transferability and better microhardness.

[0017] In addition, due to the introduction of nanoparticles, they are all modified and have better dispersibility. The modifier is prepared by the click reaction of polyethylene glycol monoallyl ether and 2-mercaptonicotinic acid. The polyethylene glycol segment can be used as an adjuvant for sodium dodecyl sulfate, making the nanoparticles have better dispersibility; while the nicotinic acid segment can promote the smoothness of surface deposition and improve the surface properties of the nickel-phosphorus layer. Specific Embodiments

[0018] 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.

[0019] It should be noted that there are no special restrictions on the purchasing manufacturers of all raw materials involved in the present invention. Exemplarily, it includes: in the following embodiments, the material model of the aluminum alloy wheel is 7A09; the particle size of nano-silicon carbide is 40-60 nm, the particle size of nano-aluminum oxide is 30-50 nm, and the CAS number of 2-mercaptonicotinic acid is 38521-46-9; the above-mentioned and other raw materials involved are all commercially available.

[0020] The preparation processes of modified nano-silicon carbide and modified nano-aluminum oxide are the same. The following parts are in parts by weight; it includes the following steps: S1-1: Add polyethylene glycol monoallyl ether-1000 and 2-mercaptonicotinic acid with a molar ratio of 1:1 to DMF, and add the photoinitiator DMPA; at room temperature, in a nitrogen atmosphere, irradiate with ultraviolet light for 4 hours, wash with ether, and remove the solvent to obtain the modifier; S1-2: (1) Add 5 parts of nano-silicon carbide to deionized water to form a 5wt% dispersion, add 0.2 part of the modifier and disperse evenly, adjust the PH = 7.8, stir at room temperature for 12 hours, centrifuge and wash, and dry to obtain modified nano-silicon carbide; (2) Add 5 parts of nano-aluminum oxide to deionized water to form a 5wt% dispersion, add 0.2 part of the modifier and disperse evenly, adjust the PH = 7.6, stir at room temperature for 12 hours, centrifuge and wash, and dry to obtain modified nano-aluminum oxide.

[0021] Example 1: A preparation method of a high-strength crack-resistant aluminum wheel, including the following steps: Step 1: Place the aluminum alloy wheel in an alkaline solution and perform alkaline washing at room temperature for 45 seconds; transfer it to an acidic solution, perform acid washing at room temperature for 30 seconds, wash with water, and blow dry with nitrogen to obtain a pretreated aluminum wheel; Step 2: Place the pretreated aluminum wheel in the zinc solution and perform zincification at room temperature for 15 seconds. Transfer it to a 50 wt% nitric acid aqueous solution and soak for 10 seconds. Then place it in the zinc solution again and perform secondary zincification at room temperature for 2 minutes. Wash with water and dry with air to form a zinc layer, denoted as aluminum wheel A; Step 3: Place aluminum wheel A in the first nickel-phosphorus solution for primary electrodeposition. The process parameters are: an external magnetic field of 0.08 T, a temperature of 85 °C, a stirring speed of 300 rpm, and a current density of 3.5 A / dm 2 ², and the electrodeposition time is 40 minutes. Transfer it to the second nickel-phosphorus solution for secondary electrodeposition. The process parameters are: an external magnetic field of 0.14 T, a temperature of 85 °C, a stirring speed of 300 rpm, and a current density of 2.5 A / dm 2 ², and the electrodeposition time is 20 minutes. Wash with water and dry with nitrogen to form a nickel-phosphorus layer; obtain a high-strength anti-cracking aluminum wheel; Among them, the alkaline solution includes the following components: 55 g / L sodium hydroxide, 1.5 g / L sodium dodecylbenzenesulfonate, 0.15 g / L polyethylene glycol, and the rest is deionized water; the acid solution includes the following components: 26 wt% hydrofluoric acid, 34 wt% nitric acid, and the rest is deionized water; The zinc solution includes the following components: 0.8 g / L zinc chloride, 0.01 g / L ferric chloride, 0.03 g / L copper sulfate, 3.8 g / L sodium hydroxide, 0.08 g / L sodium tartrate, 0.08 g / L sodium dodecylbenzenesulfonate, 0.02 g / L polyethylene glycol, and the rest is deionized water; The first nickel-phosphorus solution includes the following components: 25 g / L nickel chloride, 20 g / L nickel sulfate, 16 g / L sodium hypophosphite, 22 g / L trisodium citrate, 43 g / L ammonium chloride, 2 g / L modified nano silicon carbide, 0.08 g / L sodium dodecylbenzenesulfonate; adjust the pH = 4.8; The second nickel-phosphorus solution includes the following components: 20 g / L nickel chloride, 30 g / L nickel sulfate, 20 g / L sodium hypophosphite, 0.15 g / L thiourea, 28 g / L trisodium citrate, 42 g / L ammonium chloride, 2 g / L modified nano aluminum oxide, 0.08 g / L sodium dodecyl sulfate; adjust the pH = 5.0.

[0022] Example 2: A method for preparing a high-strength anti-cracking aluminum wheel, including the following steps: Step 1: Place the aluminum alloy wheel in the alkaline solution and perform alkaline washing at room temperature for 45 seconds; transfer it to the acid solution and perform acid washing at room temperature for 30 seconds, wash with water and dry with nitrogen to obtain a pretreated aluminum wheel; Step 2: Place the pretreated aluminum wheel in the zinc solution and perform zincification at room temperature for 15 seconds. Transfer it to a 50 wt% nitric acid aqueous solution and soak for 10 seconds. Then place it in the zinc solution again and perform secondary zincification at room temperature for 2 minutes. Wash with water and dry with air to form a zinc layer, denoted as aluminum wheel A; Step 3: Place the aluminum wheel A in the first nickel - phosphorus solution for primary electrodeposition. The process parameters are: an external magnetic field of 0.05 T, a temperature of 85 °C, a stirring speed of 300 rpm, and a current density of 4 A / dm 2 ; transfer it to the second nickel - phosphorus solution for secondary electrodeposition. The process parameters are: an external magnetic field of 0.12 T, a temperature of 85 °C, a stirring speed of 300 rpm, and a current density of 3 A / dm 2 ; the electrodeposition time is 25 minutes; wash with water and dry with nitrogen to form a nickel - phosphorus layer; obtain a high - strength crack - resistant aluminum wheel; Among them, the alkaline solution includes the following components: 50 g / L sodium hydroxide, 1.5 g / L sodium dodecylbenzenesulfonate, 0.1 g / L polyethylene glycol, and the rest is deionized water; the acidic solution includes the following components: 25 wt% hydrofluoric acid, 35 wt% nitric acid, and the rest is deionized water; The zinc solution includes the following components: 0.6 g / L zinc chloride, 0.01 g / L ferric chloride, 0.02 g / L copper sulfate, 3.5 g / L sodium hydroxide, 0.05 g / L sodium tartrate, 0.08 g / L sodium dodecylbenzenesulfonate, 0.01 g / L polyethylene glycol, and the rest is deionized water; The first nickel - phosphorus solution includes the following components: 20 g / L nickel chloride, 15 g / L nickel sulfate, 15 g / L sodium hypophosphite, 20 g / L trisodium citrate, 40 g / L ammonium chloride, 1.5 g / L modified nano - silicon carbide, 0.05 g / L sodium dodecylbenzenesulfonate; adjust the pH = 4.6; The second nickel - phosphorus solution includes the following components: 20 g / L nickel chloride, 25 g / L nickel sulfate, 18 g / L sodium hypophosphite, 0.1 g / L thiourea, 25 g / L trisodium citrate, 40 g / L ammonium chloride, 1.5 g / L modified nano - alumina, 0.05 g / L sodium dodecyl sulfate; adjust the pH = 4.8.

[0023] Example 3: A method for preparing a high - strength crack - resistant aluminum wheel, comprising the following steps: Step 1: Place the aluminum alloy wheel in the alkaline solution and perform alkaline washing at room temperature for 45 seconds; transfer it to the acidic solution and perform acid washing at room temperature for 30 seconds, wash with water and dry with nitrogen to obtain a pretreated aluminum wheel; Step 2: Place the pretreated aluminum wheel in the zinc solution and perform primary zinc plating at room temperature for 15 seconds, transfer it to a 50 wt% nitric acid aqueous solution and soak for 10 seconds, then place it in the zinc solution again and perform secondary zinc plating at room temperature for 2 minutes, wash with water and dry to form a zinc layer, denoted as aluminum wheel A; Step 3: Place the aluminum wheel A in the first nickel - phosphorus solution for primary electrodeposition. The process parameters are: an external magnetic field of 0.1 T, a temperature of 85 °C, a stirring speed of 300 rpm, and a current density of 3 A / dm 2, the electroplating time is 40 minutes; transfer it to the second nickel - phosphorus solution for secondary electroplating, and the process parameters are: the applied magnetic field is 0.14 T, the temperature is 85 °C, the stirring speed is 300 rpm, and the current density is 2 A / dm 2 , the electroplating time is 20 minutes; wash with water and dry with nitrogen to form a nickel - phosphorus layer; obtain a high - strength crack - resistant aluminum wheel; Among them, the alkaline solution includes the following components: 60 g / L sodium hydroxide, 1.8 g / L sodium dodecylbenzenesulfonate, 0.2 g / L polyethylene glycol, and the rest is deionized water; the acidic solution includes the following components: 30 wt% hydrofluoric acid, 35 wt% nitric acid, and the rest is deionized water; The zinc solution includes the following components: 1 g / L zinc chloride, 0.012 g / L ferric chloride, 0.05 g / L copper sulfate, 4 g / L sodium hydroxide, 0.1 g / L sodium tartrate, 0.1 g / L sodium dodecylbenzenesulfonate, 0.02 g / L polyethylene glycol, and the rest is deionized water; The first nickel - phosphorus solution includes the following components: 30 g / L nickel chloride, 25 g / L nickel sulfate, 18 g / L sodium hypophosphite, 25 g / L trisodium citrate, 45 g / L ammonium chloride, 2.5 g / L modified nano - silicon carbide, 0.1 g / L sodium dodecylbenzenesulfonate; adjust the pH = 4.8; The second nickel - phosphorus solution includes the following components: 25 g / L nickel chloride, 35 g / L nickel sulfate, 22 g / L sodium hypophosphite, 0.2 g / L thiourea, 30 g / L trisodium citrate, 45 g / L ammonium chloride, 2.5 g / L modified nano - aluminum oxide, 0.1 g / L sodium dodecyl sulfate; adjust the pH = 4.9.

[0024] Comparative Example 1: The copper sulfate is not set in the zinc solution, and the rest is the same as in Example 1; specifically as follows: Step 1: Place the aluminum alloy wheel in the alkaline solution and perform alkaline cleaning at room temperature for 45 seconds; transfer it to the acidic solution and perform acid cleaning at room temperature for 30 seconds, wash with water and dry with nitrogen to obtain a pretreated aluminum wheel; Step 2: Place the pretreated aluminum wheel in the zinc solution and perform primary zinc plating at room temperature for 15 seconds, transfer it to a 50 wt% nitric acid aqueous solution and soak for 10 seconds, then place it in the zinc solution again and perform secondary zinc plating at room temperature for 2 minutes, wash with water and dry to form a zinc layer, denoted as aluminum wheel A; Step 3: Place aluminum wheel A in the first nickel - phosphorus solution for primary electroplating, and the process parameters are: the applied magnetic field is 0.08 T, the temperature is 85 °C, the stirring speed is 300 rpm, and the current density is 3.5 A / dm 2 , the electroplating time is 40 minutes; transfer it to the second nickel - phosphorus solution for secondary electroplating, and the process parameters are: the applied magnetic field is 0.14 T, the temperature is 85 °C, the stirring speed is 300 rpm, and the current density is 2.5 A / dm 2, the electro - deposition time is 20 minutes; wash with water and dry with nitrogen to form a nickel - phosphorus layer; obtain a high - strength anti - cracking aluminum wheel; Among them, the alkaline solution includes the following components: 55 g / L sodium hydroxide, 1.5 g / L sodium dodecylbenzenesulfonate, 0.15 g / L polyethylene glycol, and the rest is deionized water; the acidic solution includes the following components: 26 wt% hydrofluoric acid, 34 wt% nitric acid, and the rest is deionized water; The zinc solution includes the following components: 0.8 g / L zinc chloride, 0.01 g / L ferric chloride, 0.03 g / L copper sulfate, 3.8 g / L sodium hydroxide, 0.08 g / L sodium tartrate, 0.08 g / L sodium dodecylbenzenesulfonate, 0.02 g / L polyethylene glycol, and the rest is deionized water; The first nickel - phosphorus solution includes the following components: 25 g / L nickel chloride, 20 g / L nickel sulfate, 16 g / L sodium hypophosphite, 22 g / L trisodium citrate, 43 g / L ammonium chloride, 2 g / L modified nano - silicon carbide, 0.08 g / L sodium dodecylbenzenesulfonate; adjust the pH = 4.8; The second nickel - phosphorus solution includes the following components: 20 g / L nickel chloride, 30 g / L nickel sulfate, 20 g / L sodium hypophosphite, 0.15 g / L thiourea, 28 g / L trisodium citrate, 42 g / L ammonium chloride, 2 g / L modified nano - aluminum oxide, 0.08 g / L sodium dodecyl sulfate; adjust the pH = 5.0.

[0025] Comparative Example 2: Only a single nickel - phosphorus layer is plated, and the rest is the same as in Example 1; specifically as follows: Step 1: Place the aluminum alloy wheel in the alkaline solution and perform alkaline washing at room temperature for 45 seconds; transfer it to the acidic solution and perform acid washing at room temperature for 30 seconds, wash with water and dry with nitrogen to obtain a pretreated aluminum wheel; Step 2: Place the pretreated aluminum wheel in the zinc solution and perform primary zinc plating at room temperature for 15 seconds, transfer it to a 50 wt% nitric acid aqueous solution and soak for 10 seconds, then place it in the zinc solution again and perform secondary zinc plating at room temperature for 2 minutes, wash with water and dry to form a zinc layer, denoted as aluminum wheel A; Step 3: Place aluminum wheel A in the first nickel - phosphorus solution for primary electro - deposition. The process parameters are: the applied magnetic field is 0.08 T, the temperature is 85 °C, the stirring speed is 300 rpm, and the current density is 3.5 A / dm 2 , the electro - deposition time is 60 minutes; wash with water and dry with nitrogen to form a nickel - phosphorus layer; obtain a high - strength anti - cracking aluminum wheel; Among them, the alkaline solution includes the following components: 55 g / L sodium hydroxide, 1.5 g / L sodium dodecylbenzenesulfonate, 0.15 g / L polyethylene glycol, and the rest is deionized water; the acidic solution includes the following components: 26 wt% hydrofluoric acid, 34 wt% nitric acid, and the rest is deionized water; The zinc solution comprises the following components: 0.8 g / L zinc chloride, 0.01 g / L iron chloride, 0.03 g / L copper sulfate, 3.8 g / L sodium hydroxide, 0.08 g / L sodium tartrate, 0.08 g / L sodium dodecylbenzenesulfonate, 0.02 g / L polyethylene glycol, and the balance being deionized water; The first nickel-phosphorus solution comprises the following components: 25 g / L nickel chloride, 20 g / L nickel sulfate, 16 g / L sodium hypophosphite, 22 g / L trisodium citrate, 43 g / L ammonium chloride, 2 g / L modified nano silicon carbide, 0.08 g / L sodium dodecylbenzenesulfonate; adjust the pH to 4.8.

[0026] Comparative Example 3: No magnetic field is set in both the primary electrodeposition and the secondary electrodeposition, and the rest is the same as in Example 1; specifically as follows: Step 1: Place the aluminum alloy wheel in an alkaline solution and perform alkaline cleaning at room temperature for 45 seconds; transfer it to an acidic solution, perform acid cleaning at room temperature for 30 seconds, wash with water, and dry with nitrogen to obtain a pretreated aluminum wheel; Step 2: Place the pretreated aluminum wheel in the zinc solution and perform primary zinc plating at room temperature for 15 seconds, transfer it to a 50 wt% nitric acid aqueous solution and soak for 10 seconds, then place it in the zinc solution again and perform secondary zinc plating at room temperature for 2 minutes, wash with water and dry with nitrogen to form a zinc layer, denoted as aluminum wheel A; Step 3: Place aluminum wheel A in the first nickel-phosphorus solution for primary electrodeposition, and the process parameters are: temperature is 85 °C, stirring speed is 300 rpm, current density is 3.5 A / dm 2 、electrodeposition time is 40 minutes; transfer it to the second nickel-phosphorus solution for secondary electrodeposition, and the process parameters are: temperature is 85 °C, stirring speed is 300 rpm, current density is 2.5 A / dm 2 、electrodeposition time is 20 minutes; wash with water and dry with nitrogen to form a nickel-phosphorus layer; obtain a high-strength anti-cracking aluminum wheel; Among them, the alkaline solution comprises the following components: 55 g / L sodium hydroxide, 1.5 g / L sodium dodecylbenzenesulfonate, 0.15 g / L polyethylene glycol, and the balance being deionized water; the acidic solution comprises the following components: 26 wt% hydrofluoric acid, 34 wt% nitric acid, and the balance being deionized water; The zinc solution comprises the following components: 0.8 g / L zinc chloride, 0.01 g / L iron chloride, 0.03 g / L copper sulfate, 3.8 g / L sodium hydroxide, 0.08 g / L sodium tartrate, 0.08 g / L sodium dodecylbenzenesulfonate, 0.02 g / L polyethylene glycol, and the balance being deionized water; The first nickel-phosphorus solution comprises the following components: 25 g / L nickel chloride, 20 g / L nickel sulfate, 16 g / L sodium hypophosphite, 22 g / L trisodium citrate, 43 g / L ammonium chloride, 2 g / L modified nano silicon carbide, 0.08 g / L sodium dodecylbenzenesulfonate; adjust the pH to 4.8; The second nickel-phosphorus solution comprises the following components: 20 g / L nickel chloride, 30 g / L nickel sulfate, 20 g / L sodium hypophosphite, 0.15 g / L thiourea, 28 g / L trisodium citrate, 42 g / L ammonium chloride, 2 g / L modified nano-aluminum oxide, 0.08 g / L sodium dodecyl sulfate; adjust the pH to 5.0.

[0027] Comparative Example 4: Swap the first nickel-phosphorus solution with the second nickel-phosphorus solution, and the rest is the same as in Example 1; specifically as follows: Step 1: Place the aluminum alloy wheel in an alkaline solution and perform alkaline cleaning at room temperature for 45 seconds; transfer it to an acidic solution and perform acid cleaning at room temperature for 30 seconds, then wash with water and blow dry with nitrogen to obtain a pretreated aluminum wheel. Step 2: Place the pretreated aluminum wheel in a zinc solution and perform primary zinc plating at room temperature for 15 seconds, transfer it to a 50 wt% nitric acid aqueous solution and soak for 10 seconds, then place it in the zinc solution again and perform secondary zinc plating at room temperature for 2 minutes, wash with water and blow dry to form a zinc layer, denoted as aluminum wheel A. Step 3: Place aluminum wheel A in the first nickel-phosphorus solution for primary electrodeposition. The process parameters are: the applied magnetic field is 0.08 T, the temperature is 85 °C, the stirring speed is 300 rpm, and the current density is 3.5 A / dm 2 、The electrodeposition time is 40 minutes; transfer it to the second nickel-phosphorus solution for secondary electrodeposition. The process parameters are: the applied magnetic field is 0.14 T, the temperature is 85 °C, the stirring speed is 300 rpm, and the current density is 2.5 A / dm 2 、The electrodeposition time is 20 minutes; wash with water and blow dry with nitrogen to form a nickel-phosphorus layer; obtain a high-strength anti-cracking aluminum wheel. Among them, the alkaline solution comprises the following components: 55 g / L sodium hydroxide, 1.5 g / L sodium dodecylbenzenesulfonate, 0.15 g / L polyethylene glycol, and the rest is deionized water; the acidic solution comprises the following components: 26 wt% hydrofluoric acid, 34 wt% nitric acid, and the rest is deionized water; The zinc solution comprises the following components: 0.8 g / L zinc chloride, 0.01 g / L ferric chloride, 0.03 g / L copper sulfate, 3.8 g / L sodium hydroxide, 0.08 g / L sodium tartrate, 0.08 g / L sodium dodecylbenzenesulfonate, 0.02 g / L polyethylene glycol, and the rest is deionized water; The first nickel-phosphorus solution comprises the following components: 20 g / L nickel chloride, 30 g / L nickel sulfate, 20 g / L sodium hypophosphite, 0.15 g / L thiourea, 28 g / L trisodium citrate, 42 g / L ammonium chloride, 2 g / L modified nano-aluminum oxide, 0.08 g / L sodium dodecyl sulfate; adjust the pH to 5.0; The second nickel-phosphorus solution comprises the following components: 25 g / L nickel chloride, 20 g / L nickel sulfate, 16 g / L sodium hypophosphite, 22 g / L trisodium citrate, 43 g / L ammonium chloride, 2 g / L modified nano-silicon carbide, 0.08 g / L sodium dodecylbenzenesulfonate; adjust the pH to 4.8.

[0028] Comparative Example 5: Neither the modified nano silicon carbide nor the modified nano alumina was modified, and the rest was the same as in Example 1; specifically as follows: Step 1: Place the aluminum alloy wheel in an alkaline solution and perform alkaline cleaning at room temperature for 45 seconds; transfer it to an acidic solution, perform acid cleaning at room temperature for 30 seconds, wash with water, and dry with nitrogen to obtain a pretreated aluminum wheel; Step 2: Place the pretreated aluminum wheel in a zinc solution and perform primary zinc plating at room temperature for 15 seconds. Transfer it to a 50 wt% nitric acid aqueous solution and soak for 10 seconds. Then place it in the zinc solution again and perform secondary zinc plating at room temperature for 2 minutes. Wash with water and dry with nitrogen to form a zinc layer, denoted as aluminum wheel A; Step 3: Place aluminum wheel A in the first nickel-phosphorus solution for primary electrodeposition. The process parameters are: an external magnetic field of 0.08 T, a temperature of 85 °C, a stirring speed of 300 rpm, and a current density of 3.5 A / dm 2 ², and the electrodeposition time is 40 minutes; transfer it to the second nickel-phosphorus solution for secondary electrodeposition. The process parameters are: an external magnetic field of 0.14 T, a temperature of 85 °C, a stirring speed of 300 rpm, and a current density of 2.5 A / dm 2 ², and the electrodeposition time is 20 minutes; wash with water and dry with nitrogen to form a nickel-phosphorus layer; obtain a high-strength anti-cracking aluminum wheel; Among them, the alkaline solution includes the following components: 55 g / L sodium hydroxide, 1.5 g / L sodium dodecylbenzenesulfonate, 0.15 g / L polyethylene glycol, and the rest is deionized water; the acidic solution includes the following components: 26 wt% hydrofluoric acid, 34 wt% nitric acid, and the rest is deionized water; The zinc solution includes the following components: 0.8 g / L zinc chloride, 0.01 g / L ferric chloride, 0.03 g / L copper sulfate, 3.8 g / L sodium hydroxide, 0.08 g / L sodium tartrate, 0.08 g / L sodium dodecylbenzenesulfonate, 0.02 g / L polyethylene glycol, and the rest is deionized water; The first nickel-phosphorus solution includes the following components: 25 g / L nickel chloride, 20 g / L nickel sulfate, 16 g / L sodium hypophosphite, 22 g / L trisodium citrate, 43 g / L ammonium chloride, 2 g / L nano silicon carbide, 0.08 g / L sodium dodecylbenzenesulfonate; adjust the pH = 4.8; The second nickel-phosphorus solution includes the following components: 20 g / L nickel chloride, 30 g / L nickel sulfate, 20 g / L sodium hypophosphite, 0.15 g / L thiourea, 28 g / L trisodium citrate, 42 g / L ammonium chloride, 2 g / L nano alumina, 0.08 g / L sodium dodecyl sulfate; adjust the pH = 5.0.

[0029] Performance Test 1: Perform performance tests on the high-strength crack-resistant aluminum wheels in the examples and comparative examples; (1) Through a tensile test, set a tensile rate of 2 mm / min, and the time when the first crack appears in the nickel-phosphorus layer is used to characterize the crack resistance of the coating, and the adhesion of the coating is verified on the side. (2) Test the micro-Vickers hardness of the coating through a microhardness tester; the load is 100 g and the loading time is 10 seconds; the micro-introduction of the coating is obtained to characterize the hardness. (3) Use an electrochemical workstation, use 3.5% sodium chloride as the electrolyte, and adopt standard three-electrode testing to obtain the corrosion current density to characterize its corrosion resistance. The data are shown in the following table: Sample Crack appearance time (S) Microhardness (VHN) <![CDATA[Corrosion current density (μA / cm 2 )]]> Example 1 617 723 1.24 Comparative Example 1 572 721 1.31 Comparative Example 2 507 632 1.43 Comparative Example 3 560 651 1.35 Comparative Example 4 536 644 1.39 Comparative Example 5 551 659 1.36 Conclusion: It can be seen from the data in the above table that: in the solution, through the activation of a specific zinc solution and the double-layer plating under the setting of a magnetic field with a specific nickel-phosphorus solution, a crack-resistant aluminum wheel with high hardness and corrosion resistance is effectively obtained. It can be seen from the data of Comparative Example 1 to Comparative Example 5 that: in Comparative Example 1, since the zinc solution does not contain copper sulfate, the uniformity of zincification is reduced, resulting in a decrease in interface bonding, crack resistance and corrosion resistance. In Comparative Example 2, since only a nickel-phosphorus layer is plated alone, the surface defects are large, resulting in a decrease in related properties. In Comparative Example 3, since no magnetic field is set in the primary electrodeposition and the secondary electrodeposition, the deposited grains become larger and the performance decreases. In Comparative Example 4, since the first nickel-phosphorus solution and the second nickel-phosphorus solution are swapped, the surface hardness and corrosion resistance decrease. In Comparative Example 5, since neither the modified nano-silicon carbide nor the modified nano-aluminum oxide is modified, the dispersion of nano-particles decreases, and since it does not contain nicotinic acid groups, the surface performance of the coating decreases.

[0030] Finally, it should be noted that: the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A preparation method of a high-strength crack-resistant aluminum wheel, characterized in that: It includes the following steps: Step 1: Alkaline wash, acid wash, and water wash and dry the aluminum alloy wheel to obtain a pretreated aluminum wheel; Step 2: Subject the pretreated aluminum wheel to primary zincification in zinc solution, transfer it to soak in nitric acid solution, and then subject it to secondary zincification in zinc solution again, followed by water wash and drying to form a zinc layer, denoted as aluminum wheel A; Step 3: Subject aluminum wheel A to primary electrodeposition in the first nickel-phosphorus solution, transfer it to the second nickel-phosphorus solution for secondary electrodeposition, followed by water wash and drying to form a nickel-phosphorus layer; a high-strength anti-cracking aluminum wheel is obtained.

2. The preparation method of a high-strength crack-resistant aluminum wheel according to claim 1, characterized in that: The zinc solution includes the following components: 0.6 - 1 g / L zinc chloride, 0.01 - 0.012 g / L ferric chloride, 0.02 - 0.05 g / L copper sulfate, 3.5 - 4 g / L sodium hydroxide, 0.05 - 0.1 g / L sodium tartrate, 0.08 - 0.1 g / L sodium dodecylbenzenesulfonate, 0.01 - 0.02 g / L polyethylene glycol, and the rest is deionized water.

3. The preparation method of a high-strength crack-resistant aluminum wheel according to claim 2, characterized in that: The process parameters for the primary zincification are: primary zincification for 10 - 15 seconds at room temperature; the concentration of the nitric acid solution is 40 - 50 wt% nitric acid aqueous solution, and the soaking time is 5 - 15 seconds; the process parameters for the secondary zincification are: secondary zincification for 1 - 3 minutes at room temperature.

4. The preparation method of a high-strength anti-cracking aluminum wheel according to claim 1, characterized in that: The first nickel-phosphorus solution includes the following components: 20 - 30 g / L nickel chloride, 15 - 25 g / L nickel sulfate, 15 - 18 g / L sodium hypophosphite, 20 - 25 g / L trisodium citrate, 40 - 45 g / L ammonium chloride, 1.5 - 2.5 g / L modified nano silicon carbide, 0.05 - 0.1 g / L sodium dodecylbenzenesulfonate; adjust the pH = 4.5 - 5.5; The second nickel-phosphorus solution includes the following components: 20 - 25 g / L nickel chloride, 25 - 35 g / L nickel sulfate, 18 - 22 g / L sodium hypophosphite, 0.1 - 0.2 g / L thiourea, 25 - 30 g / L trisodium citrate, 40 - 45 g / L ammonium chloride, 1.5 - 2.5 g / L modified nano alumina, 0.05 - 0.1 g / L sodium dodecyl sulfate; adjust the pH = 4.5 - 5.

5.

5. The preparation method of a high-strength crack-resistant aluminum wheel according to claim 1, characterized in that: The process parameters of the primary electroplating are as follows: the applied magnetic field is 0.05 - 0.1 T, the temperature is 85 - 90 °C, the stirring speed is 100 - 300 rpm, and the current density is 3 - 4 A / dm 2 , and the electroplating time is 35 - 40 minutes.

6. The preparation method of a high-strength crack-resistant aluminum wheel according to claim 1, characterized in that: The process parameters of the secondary electrodeposition are as follows: the applied magnetic field is 0.12 - 0.14 T, the temperature is 85 - 90 °C, the stirring speed is 100 - 300 rpm, and the current density is 2 - 3 A / dm 2 , and the electrodeposition time is 20 - 25 minutes.

7. The preparation method of a high-strength anti-cracking aluminum wheel according to claim 4, characterized in that: The preparation processes of the modified nano silicon carbide and the modified nano alumina are the same; they include the following steps: S1-1: Add polyethylene glycol monoallyl ether and 2-mercaptonicotinic acid with a molar ratio of 1:1 to DMF, and add a photoinitiator; under nitrogen atmosphere at room temperature, irradiate with ultraviolet light for 2 - 4 hours, wash with ether, and remove the solvent to obtain a modifier; S1-2: Add nano silicon carbide or nano alumina to deionized water, add the modifier and disperse evenly, adjust the pH = 7.5 - 8, stir at room temperature for 6 - 12 hours, centrifuge and wash, and dry to obtain modified nano silicon carbide or modified nano alumina.

8. The preparation method of a high-strength crack-resistant aluminum wheel according to claim 1, characterized in that: The alkaline solution for the alkaline wash includes the following components: 50 - 60 g / L sodium hydroxide, 1.5 - 1.8 g / L sodium dodecylbenzenesulfonate, 0.1 - 0.2 g / L polyethylene glycol, and the rest is deionized water; the process parameters for the alkaline wash are: alkaline wash for 15 - 60 seconds at room temperature; The acid solution for the acid wash includes the following components: 25 - 30 wt% hydrofluoric acid, 30 - 35 wt% nitric acid, and the rest is deionized water; the process parameters for the acid wash are: acid wash for 10 - 60 seconds at room temperature. A high-strength crack-resistant aluminum wheel prepared by the method for preparing a high-strength crack-resistant aluminum wheel according to any one of claims 1 to 8.