Aluminum-plated alloy copper workpiece as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of metal materials, and particularly relates to an aluminum alloy-plated copper workpiece and a preparation method and application thereof, and the aluminum alloy-plated copper workpiece comprises a copper workpiece substrate and an aluminum alloy plating layer coating the copper workpiece substrate; the aluminum alloy coating comprises the following components in percentage by mass: 0.1%-13.0% of silicon, 0.3%-5.0% of magnesium, 0.1%-0.4% of rare earth elements and the balance of aluminum and inevitable impurities; the rare earth elements comprise cerium and lanthanum in a mass ratio of (1: 25)-(2: 1). The preparation method comprises the following steps: cleaning a copper workpiece substrate, putting the copper workpiece substrate into a plating assistant, taking out the copper workpiece substrate, drying the copper workpiece substrate, preheating the copper workpiece substrate, and putting the copper workpiece substrate into aluminum alloy liquid for hot dipping to obtain the aluminum-plated alloy copper workpiece. The aluminum-plated alloy copper workpiece simultaneously has the advantages of good conductivity, easiness in welding and low contact resistance of a copper material and light weight and low cost of an aluminum material, and can simply realize safe connection of an aluminum wire and the workpiece.

Description

Technical Field

[0001] The invention belongs to the technical field of metal materials, and in particular relates to an aluminum alloy-plated copper workpiece and a preparation method and application thereof. Background Art

[0002] In the development of the power system, cost reduction and efficiency improvement have always been a pursuit direction. Copper alloy cables are commonly used in the market today. Compared with copper alloy cables, the cost of aluminum alloy cables can be reduced by 20%~40%, and the weight can be reduced by 3.3 times. Its safe current carrying capacity, conductivity, safety, and conductor resistivity can be completely equivalent to traditional copper wire cables. It has the advantages of low cost, easy processing, easy installation, and good transmission performance. However, in the entire power system, most of the materials used for workpieces are copper or copper alloys, such as AC switches and AC terminals in inverters and distribution cabinets. If aluminum alloy cables are used, when the conductors of copper and aluminum are directly connected, on the one hand, due to the difference in elastic modulus and thermal expansion coefficient between copper and aluminum, multiple hot and cold cycles (power on and off) will cause a large gap at the contact point, resulting in poor contact; on the other hand, the electrode potential of aluminum (-1.66 V) is low, and it is easy to lose electrons and become a negative electrode. The standard electrode potential of copper (+0.337 V~+0.521 V) is high, and it is difficult to lose electrons and become a positive electrode. When it is combined with CO in water and air, it will cause the contact point to be poor. 2 When they work together, an electrochemical galvanic cell structure will be formed, causing the aluminum material to be gradually electrochemically corroded, and the mechanical strength and conductivity will decrease rapidly, increasing the contact resistance between copper and aluminum and causing poor contact. Especially when current passes through, the increase in temperature will accelerate corrosion and even cause accidents such as smoking and burning.

[0003] At present, copper-aluminum transition connecting tubes, metal pins and secondary zinc dipping are commonly used to solve the problem of direct connection of copper-aluminum cables. Among them, the copper-aluminum transition connecting tube and metal pin method both use the copper-aluminum contact surface welding method to make the copper material and the aluminum material longitudinally distributed to achieve the connection between the copper wire and the aluminum wire. Due to process reasons, it is often impossible to miniaturize, the material loss during the operation is large, and the weld is prone to corrosion and fracture after being exposed to moisture. The secondary zinc dipping method is a method of first stripping the wire insulation wrapping layer of 15~25mm with aluminum wire pliers, pre-treating the aluminum wire head with tin, and then connecting it to the copper cable. This method is complicated to operate and has high requirements for personnel operation. In addition, in the actual operation process, ordinary electric soldering irons are generally used for direct tinning. The tin layer is easy to fall off in a short time. When the copper and aluminum come into contact with moisture, an electrochemical reaction will also occur, causing the cable to burn. Summary of the invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the problems of electrochemical corrosion, poor contact, and easy damage after being damp when conductors of copper and aluminum materials are connected in the prior art, thereby providing an aluminum alloy-plated copper workpiece and its preparation method and application.

[0005] To this end, the present invention provides the following technical solutions.

[0006] The invention provides an aluminum alloy-plated copper workpiece, comprising a copper workpiece substrate and an aluminum alloy coating coated on the copper workpiece substrate; the aluminum alloy coating comprises, by mass percentage, 0.1% to 13.0% silicon, 0.3% to 5.0% magnesium, 0.1% to 0.4% rare earth elements, and the remainder being aluminum and unavoidable impurities; the rare earth elements comprise cerium and lanthanum in a mass ratio of 1:25 to 2:1.

[0007] Optionally, it also includes a silane coating coated on the aluminum alloy coating; the thickness of the silane coating is 1-2 μm.

[0008] Optionally, the thickness of the aluminum alloy coating is 15-80 μm.

[0009] Preferably, the aluminum alloy coating includes, by mass percentage: rare earth elements: 0.1%; the rare earth elements include cerium and lanthanum in a mass ratio of 2:1.

[0010] Optionally, the copper workpiece base includes any one of a wiring nose and a transition clamp; wherein the transition clamp includes a bolt-type transition clamp. The copper workpiece base used in the present invention is not limited in size and can be selected according to the required working conditions.

[0011] Optionally, when in use, the aluminum alloy-plated copper workpiece is connected to the aluminum conductor, and an organic anti-oxidation layer is coated at the connection between the two; this can enhance the sealing performance, anti-oxidation and anti-electro-corrosion properties of the interface after the copper-aluminum contact, and effectively ensure the safety of cable installation. The connection between the aluminum alloy-plated copper workpiece and the copper conductor is not particularly limited. Typically, the aluminum alloy-plated copper workpiece is connected to the copper conductor end using a tinned copper connector commonly used in the industry, and the workpiece can be inserted into the tinned copper connector for use.

[0012] Optionally, the organic anti-oxidation layer includes at least one of an epoxy resin layer, a polyurethane layer, a phenolic resin layer, and an acrylic layer.

[0013] Optionally, the thickness of the organic anti-oxidation layer is 10-100 μm.

[0014] Optionally, when the copper workpiece substrate includes a wiring lug, the area of ​​the aluminum alloy coating on the wiring lug accounts for 1% to 25% of the total surface area of ​​the wiring lug.

[0015] The present invention also provides a method for preparing the above-mentioned aluminum alloy-plated copper workpiece, comprising the following steps: S1: cleaning the copper workpiece substrate, placing it in a plating aid, taking it out, and drying it to obtain a copper workpiece with an attached plating aid layer; S2: preheating the copper workpiece with the attached plating aid layer, placing it in an aluminum alloy liquid for hot dip plating, and obtaining an aluminum alloy-plated copper workpiece.

[0016] Optionally, the aluminum alloy liquid includes, in mass percentage: silicon: 0.1% to 13.0%, magnesium: 0.3% to 5.0%, rare earth elements: 0.1% to 0.4%, and the remainder is aluminum and unavoidable impurities; the rare earth elements include cerium and lanthanum in a mass ratio of 1:25 to 2:1.

[0017] Optionally, the hot-dip coating temperature is 670-750° C. and the time is 4-8 s.

[0018] Optionally, in S2, the preheating temperature is 200-300° C. and the time is 10-30 min.

[0019] Optionally, S2 further includes the steps of immersing the hot-dip plated copper workpiece in a silane coupling agent solution, drying, and curing.

[0020] Optionally, in S1, the plating aid includes NH 4 Cl solution, ZnCl 2 solution, KF solution, K 2 ZF 6 At least one of the solutions.

[0021] Optionally, the mass concentration of the plating aid is 0.5%~12%.

[0022] Optionally, the mass concentration of the silane coupling agent solution is 12%-16%, and the pH value is 3-5.

[0023] Optionally, the solvent of the silane coupling agent solution includes at least one of anhydrous ethanol, water, and acetic acid. Typically, but not limitedly, the preparation method of the silane coupling agent solution includes the following steps: mixing 150 mL of anhydrous ethanol and 50 mL of deionized water, adding silane coupling agent and acetic acid, first controlling the mass concentration of the silane coupling agent solution to 14%, then ensuring that the mass concentration of the silane coupling agent solution is within the range of 12% to 16%, adjusting its pH to 3 to 5, and hydrolyzing at a speed of 240 to 320 r / min for 20 to 28 hours to obtain a completely hydrolyzed silane coupling agent solution.

[0024] Optionally, the soaking time is 8 to 15 minutes.

[0025] Optionally, the curing temperature is 100~140°C and the curing time is 1.5~3 h.

[0026] Preferably, the hot-dip galvanizing temperature is 680-700°C.

[0027] Optionally, in S1, the cleaned copper workpiece substrate is placed in a plating aid at 30-60° C. for 2-4 min.

[0028] Optionally, the plating aid includes NH 4 Cl solution, or ZnCl with a mass concentration of 10%~12% 2 solution, or KF solution with a mass concentration of 1%~6%, or KF solution with a mass concentration of 1.5%~1.8%, NH 4 Cl mixed solution, or mass concentration of 0.5%~1% KF, 5%~6% NH 4 Cl mixed solution, or mass concentration of 1.5%~1.8% KF, 5%~5.5% ZnCl 2 A mixed solution of 1%~1.2% KF, 7%~8% ZnCl 2 A mixed solution of 4.2% to 5.2% K 2 ZF 6 Solution.

[0029] Optionally, in S1, cleaning the copper workpiece substrate comprises sequentially performing alkali washing and acid washing on the copper workpiece substrate. Typically, but not limitedly, after alkali washing and before acid washing, a water washing step is also included; after acid washing, a water washing step is also included before placing in a plating aid.

[0030] Optionally, in S1, the drying temperature is 100-140° C. Typically, in S1, the drying includes two steps of drying, the first step of drying includes hot air drying, and the second step of drying includes heating drying. To prevent the plating aid from absorbing moisture in the air and precipitating after the plating aid layer is attached, the surface must first be quickly dried with hot air, and then thoroughly dried.

[0031] Optionally, when used, the method further comprises the step of coating an organic anti-oxidation layer at the connection between the aluminum alloy-plated copper workpiece and the aluminum conductor after the two are connected.

[0032] Optionally, in S1, the cleaned copper workpiece substrate is placed in a 2% KF solution at 40-50° C. for 3 min, and then taken out.

[0033] Optionally, the pickling temperature is 40-60° C. and the time is 1-3 min.

[0034] Optionally, the acid solution used for pickling includes any one of sulfuric acid, hydrochloric acid, and nitric acid.

[0035] Optionally, the concentration of the acid solution used for pickling is 13-20 g / L. For example, the acid solution used for pickling can be, but is not limited to, 13 g / L sulfuric acid, 15 g / L sulfuric acid, 18 g / L sulfuric acid, 16 g / L hydrochloric acid, 18 g / L hydrochloric acid, 20 g / L hydrochloric acid, 16 g / L nitric acid, 18 g / L nitric acid, 20 g / L nitric acid, etc.

[0036] Optionally, the pH of the alkaline washing solution used for alkaline washing is 9-12, the alkaline washing temperature is 50-65°C, and the washing time is 25-35 min. The specific formula of the alkaline washing solution does not need to be strictly limited, but too low an alkali content will lead to low efficiency and poor degreasing effect; too high an alkali content will cause the generated soap to form insoluble calcium soap and magnesium soap with calcium and magnesium in the water, which will be deposited on the copper surface and difficult to remove with water. During subsequent acid washing, it will be neutralized by the acid to form an oil film of fatty acids, resulting in poor acid washing effect. Typically, the alkaline washing solution used includes 10 g / L NaOH, 25 g / L Na 2 CO 3 、55 g / L Na 3 PO 4 12H 2 O, 10 g / L Na 2 SiO 3 and 3~5 g / L drops of surfactant NP-10 (nonylphenol polyoxyethylene ether).

[0037] The present invention also provides the use of the aluminum alloy-plated copper workpiece or the aluminum alloy-plated copper workpiece prepared by the preparation method in power lines.

[0038] The beneficial effects of the present invention are: The aluminum alloy-plated copper workpiece provided by the present invention comprises a copper workpiece substrate and an aluminum alloy coating coated on the copper workpiece substrate; the aluminum alloy coating comprises, by mass percentage, silicon: 0.1% to 13.0%, magnesium: 0.3% to 5.0%, rare earth elements: 0.1% to 0.4%, and the remainder is aluminum and unavoidable impurities; the rare earth elements include cerium and lanthanum in a mass ratio of 1:25 to 2:1. The aluminum alloy-plated copper workpiece has the advantages of good electrical conductivity, easy welding, low contact resistance of copper materials, and light weight and low cost of aluminum materials, which can effectively solve the problem of electrochemical corrosion caused by direct connection of copper and aluminum cables, and can simply realize the safe connection of aluminum wires and workpieces.

[0039] By adding Si, Mg and rare earth elements Ce and La to the coating, Si can form a flaky Si structure in the coating and refine the grains; Mg can form Al with Cu and Al. 2 Cu、Al 2CuMg alloy can refine the coating grains and reduce the potential difference of the galvanic cell in the coating. On the other hand, it can enhance the corrosion resistance of the coating. It can form a dense corrosion product layer on the surface of the coating, which can isolate O and Cl elements in the environment from entering the coating; rare earth elements Ce and La can form a protective layer on the surface of the melt to prevent Al 2 O 3 The formation of the melt, purification of the melt, and improvement of the wettability of the melt on the steel surface, while preventing Al 2 O 3 The formation of Si, Mg and rare earth elements Ce and La can alleviate the coarse grains and pinhole plating phenomenon that may occur in pure aluminum coatings. The coarse grains are Al formed during the hot-dip process. 2 O 3 The particles reduce the wettability of the aluminum liquid, and the pinhole plating phenomenon is caused by the release of hydrogen absorbed in the aluminum. They will affect the corrosion resistance of the coating.

[0040] The aluminum alloy-plated copper workpiece provided by the present invention also includes a silane coating coated on the aluminum alloy coating. Using the silane coating as a passivation layer further improves the corrosion resistance of the workpiece, enables it to resist a more severe corrosion environment, and can also extend its service life to a certain extent.

[0041] The preparation method of the above-mentioned aluminum alloy-plated copper workpiece provided by the present invention comprises the following steps: S1: cleaning the copper workpiece substrate, placing it in a plating aid, taking it out, drying it, and obtaining a copper workpiece with a plating aid layer attached; S2: preheating the copper workpiece with the plating aid layer attached, placing it in an aluminum alloy liquid for hot dip plating, and obtaining an aluminum alloy-plated copper workpiece. The preparation process is simple, the professional requirements for personnel are low, and the material loss in the preparation process is small, and it is easy to carry out miniaturized preparation. The use of hot dip plating process to prepare aluminum alloy coatings does not require expensive manufacturing equipment, the process processing amount is small, it is not easy to cause waste of aluminum alloy liquid, the coating thickness is uniform, controllable, and has good corrosion resistance and high temperature resistance, and it is not easy to have problems such as fracture at the joints. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0043] Figure 1 Schematic diagram of the copper lug used in the embodiment of the present invention; Description of reference numerals: 1-Aluminum alloy coating area is coated; 2-Aluminum alloy coating area is not coated. DETAILED DESCRIPTION

[0044] The following examples are provided for a better understanding of the present invention, but are not intended to limit the best mode of implementation, nor to limit the content and protection scope of the present invention. Any product identical or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with other prior arts shall fall within the protection scope of the present invention.

[0045] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in the field can be used. If no manufacturer is specified for the reagents or instruments used, they are all conventional reagent products that can be obtained commercially.

[0046] Experimental drugs: Silane coupling agent: n-octyltriethoxysilane (OTES).

[0047] Example 1 This embodiment provides an aluminum alloy-plated copper workpiece and a preparation method thereof. The copper workpiece substrate used is as follows Figure 1 The copper lug shown in the figure has an aluminum alloy coating area 1 in the dotted frame and an uncoated aluminum alloy coating area 2 in the rest. The alkaline cleaning solution used is: 1000 mL containing 10 g / L NaOH, 25 g / L Na 2 CO 3 、55 g / L Na 3 PO 4 12H 2 O, 10g / L Na 2 SiO 3 The alkaline cleaning solution used was 15 g / L H 2 SO 4 ; The plating aid used is: 2wt% KF solution; The aluminum alloy liquid used includes, by mass percentage: silicon: 8%; magnesium: 2%; rare earth elements: 0.1% (wherein the mass ratio of cerium to lanthanum is 2:1), and the remainder is aluminum and unavoidable impurities; The preparation method of the silane coupling agent solution used includes the following steps: mixing 150 mL of anhydrous ethanol and 50 mL of deionized water, adding silane coupling agent and acetic acid, controlling the mass concentration of the silane coupling agent solution to 14%, adjusting its pH to 4, and hydrolyzing at a speed of 280 r / min for 24 h to obtain a completely hydrolyzed silane coupling agent solution. Specifically including the following steps: (1) Figure 1The aluminum alloy-coated area 1 of the copper terminal lug shown (subsequent treatments of the copper terminal lug are only to this part) is immersed in an alkaline cleaning solution and immersed at 55°C for 30 min; rinsed with clean water; then placed in an acid cleaning solution and immersed at 50°C for 2 min; rinsed with clean water; the copper terminal lug is immersed in a plating aid at 45°C for 3 min, taken out, first dried with hot air to quickly dry the surface, and then transferred to a drying oven to be thoroughly dried at 120°C to obtain a copper terminal lug with an attached plating aid layer.

[0048] (2) The copper terminal lug with the plating aid layer was preheated at 230°C for 15 min, placed in an aluminum alloy liquid and hot-dip plated at 690°C for 6 s to obtain a copper terminal lug coated with an aluminum alloy layer.

[0049] (3) The copper terminal lug coated with aluminum alloy is immersed in a silane coupling agent solution for 10 min, taken out and blown dry, and then placed in a drying oven at 120°C for curing for 2 h to obtain an aluminum alloy-plated copper terminal lug.

[0050] Example 2 This embodiment provides an aluminum alloy-plated copper workpiece and a preparation method thereof. The copper workpiece substrate used is as follows Figure 1 The copper lug shown in the figure has an aluminum alloy coating area 1 in the dotted frame and an uncoated aluminum alloy coating area 2 in the rest. The alkaline cleaning solution used is: 1000 mL containing 10 g / L NaOH, 25 g / L Na 2 CO 3 、55 g / L Na 3 PO 4 12H 2 O, 10g / L Na 2 SiO 3 and 4 g / L surfactant NP-10 alkaline washing solution, pH 10; the acid washing solution used is: 18 g / L HCl; the plating aid used is: 1wt% KF solution; the aluminum alloy liquid used includes by mass percentage: silicon: 6%; magnesium: 1%; rare earth elements: 0.3% (wherein the mass ratio of cerium and lanthanum is 1:2), and the balance is aluminum and unavoidable impurities; the preparation method of the silane coupling agent solution used includes the following steps: mixing 150 mL of anhydrous ethanol and 50 mL of deionized water, adding silane coupling agent and acetic acid, controlling the mass concentration of the silane coupling agent solution to 14%, adjusting its pH to 4, and hydrolyzing at a speed of 280 r / min for 24 h to obtain a completely hydrolyzed silane coupling agent solution. Specifically including the following steps: (1) Figure 1The aluminum alloy-coated area 1 of the copper terminal lug shown (subsequent treatments of the copper terminal lug are only to this part) is immersed in an alkaline cleaning solution and immersed at 65°C for 25 min; rinsed with clean water; then placed in an acid cleaning solution and immersed at 60°C for 1 min; rinsed with clean water; the copper terminal lug is immersed in a plating aid at 30°C for 4 min, taken out, first dried with hot air to quickly dry the surface, and then transferred to a drying oven and thoroughly dried at 100°C to obtain a copper terminal lug with an attached plating aid layer.

[0051] (2) The copper terminal lug with the plating aid layer was preheated at 200°C for 30 min, placed in an aluminum alloy liquid and hot-dip plated at 680°C for 8 s to obtain a copper terminal lug coated with an aluminum alloy layer.

[0052] (3) The copper terminal lug coated with aluminum alloy was immersed in a silane coupling agent solution for 8 min, taken out and blown dry, and then placed in a drying oven at 100 °C for curing for 3 h to obtain an aluminum alloy-plated copper terminal lug.

[0053] Example 3 This embodiment provides an aluminum alloy-plated copper workpiece and a preparation method thereof. The copper workpiece substrate used is as follows Figure 1 The copper lug shown in the figure has an aluminum alloy coating area 1 in the dotted frame and an uncoated aluminum alloy coating area 2 in the rest. The alkaline cleaning solution used is: 1000 mL containing 10 g / L NaOH, 25 g / L Na 2 CO 3 、55 g / L Na 3 PO 4 12H 2 O, 10g / L Na 2 SiO 3 The alkaline cleaning solution used was 4 g / L surfactant NP-10, pH 10; the acid cleaning solution used was 18 g / L HNO 3 ; The plating aid used is: 4wt% KF solution; The aluminum alloy liquid used includes, by mass percentage: silicon: 9%; magnesium: 3%; rare earth elements: 0.2% (wherein the mass ratio of cerium to lanthanum is 1:1), and the balance is aluminum and unavoidable impurities; The preparation method of the silane coupling agent solution used includes the following steps: mixing 150 mL of anhydrous ethanol and 50 mL of deionized water, adding silane coupling agent and acetic acid, controlling the mass concentration of the silane coupling agent solution to 14%, adjusting its pH to 4, and hydrolyzing at a speed of 280 r / min for 24 h to obtain a completely hydrolyzed silane coupling agent solution. Specifically including the following steps: (1) Figure 1The aluminum alloy-coated area 1 of the copper terminal lug shown (subsequent treatments of the copper terminal lug are only to this part) is immersed in an alkaline cleaning solution at 50°C for 35 min; rinsed with clean water; then placed in an acid cleaning solution at 40°C for 3 min; rinsed with clean water; the copper terminal lug is immersed in a plating aid at 60°C for 2 min, taken out, first dried with hot air to quickly dry the surface, and then transferred to a drying oven to be thoroughly dried at 140°C to obtain a copper terminal lug with an attached plating aid layer.

[0054] (2) The copper terminal lug with the plating aid layer was preheated at 300°C for 10 min, placed in aluminum alloy liquid and hot-dip plated at 700°C for 4 s to obtain a copper terminal lug coated with an aluminum alloy layer.

[0055] (3) The copper terminal lug coated with aluminum alloy was immersed in a silane coupling agent solution for 15 min, taken out and blown dry, and then placed in a drying oven at 140°C for curing for 1.5 h to obtain an aluminum alloy-plated copper terminal lug.

[0056] Example 4 This embodiment provides an aluminum alloy-plated copper workpiece and a preparation method thereof. The copper workpiece substrate used is as follows Figure 1 The copper lug shown in the figure has an aluminum alloy coating area 1 in the dotted frame and an uncoated aluminum alloy coating area 2 in the rest. The alkaline cleaning solution used is: 1000 mL containing 10 g / L NaOH, 25 g / L Na 2 CO 3 、55 g / L Na 3 PO 4 12H 2 O, 10g / L Na 2 SiO 3 The alkaline cleaning solution used was 4 g / L surfactant NP-10, pH 10; the acid cleaning solution used was 16 g / L HNO 3 ; The plating aids used are: 1.8wt% KF, 3wt% NH 4 Cl mixed solution; the aluminum alloy liquid used includes, by mass percentage: silicon: 0.1%; magnesium: 5%; rare earth elements: 0.4% (wherein the mass ratio of cerium to lanthanum is 1:25), and the remainder is aluminum and unavoidable impurities; the preparation method of the silane coupling agent solution used includes the following steps: mixing 150 mL of anhydrous ethanol and 50 mL of deionized water, adding silane coupling agent and acetic acid, controlling the mass concentration of the silane coupling agent solution to 14%, adjusting its pH to 3, and hydrolyzing at a speed of 280 r / min for 24 h to obtain a completely hydrolyzed silane coupling agent solution. Specifically including the following steps: (1) Figure 1The aluminum alloy-coated area 1 of the copper terminal lug shown (subsequent treatments of the copper terminal lug will only treat this part) is immersed in an alkaline cleaning solution and immersed at 55°C for 30 min; rinsed with clean water; then placed in an acid cleaning solution and immersed at 50°C for 2 min; rinsed with clean water; the copper terminal lug is immersed in a plating aid at 45°C for 3 min, taken out, first dried with hot air to quickly dry the surface, and then transferred to a drying oven to be thoroughly dried at 120°C to obtain a copper terminal lug with an attached plating aid layer.

[0057] (2) The copper terminal lug with the plating aid layer was preheated at 230°C for 15 min, placed in an aluminum alloy liquid and hot-dip plated at 750°C for 4 s to obtain a copper terminal lug coated with an aluminum alloy layer.

[0058] (3) The copper terminal lug coated with aluminum alloy is immersed in a silane coupling agent solution for 10 min, taken out and blown dry, and then placed in a drying oven at 120°C for curing for 2 h to obtain an aluminum alloy-plated copper terminal lug.

[0059] Example 5 This embodiment provides an aluminum alloy-plated copper workpiece and a preparation method thereof. The copper workpiece substrate used is as follows Figure 1 The copper lug shown in the figure has an aluminum alloy coating area 1 in the dotted frame and an uncoated aluminum alloy coating area 2 in the rest. The alkaline cleaning solution used is: 1000 mL containing 10 g / L NaOH, 25 g / L Na 2 CO 3 、55 g / L Na 3 PO 4 12H 2 O, 10g / L Na 2 SiO 3 The alkaline cleaning solution used was 4 g / L surfactant NP-10, pH 10; the acid cleaning solution used was 20 g / L HCl; the plating aids used were 1.8wt% KF, 5wt% ZnCl 2 The aluminum alloy liquid used includes, by mass percentage, silicon: 13%; magnesium: 0.3%; rare earth elements: 0.1% (wherein the mass ratio of cerium to lanthanum is 2:1), and the remainder is aluminum and unavoidable impurities; the preparation method of the silane coupling agent solution used includes the following steps: mixing 150 mL of anhydrous ethanol and 50 mL of deionized water, adding silane coupling agent and acetic acid, controlling the mass concentration of the silane coupling agent solution to 14%, adjusting its pH to 5, and hydrolyzing at a speed of 280 r / min for 24 h to obtain a completely hydrolyzed silane coupling agent solution. Specifically including the following steps: (1) Figure 1The aluminum alloy-coated area 1 of the copper terminal lug shown (subsequent treatments of the copper terminal lug will only treat this part) is immersed in an alkaline cleaning solution and immersed at 55°C for 30 min; rinsed with clean water; then placed in an acid cleaning solution and immersed at 50°C for 2 min; rinsed with clean water; the copper terminal lug is immersed in a plating aid at 45°C for 3 min, taken out, first dried with hot air to quickly dry the surface, and then transferred to a drying oven to be thoroughly dried at 120°C to obtain a copper terminal lug with an attached plating aid layer.

[0060] (2) The copper terminal lug with the plating aid layer was preheated at 230°C for 15 min, placed in an aluminum alloy liquid and hot-dip plated at 670°C for 8 s to obtain a copper terminal lug coated with an aluminum alloy layer.

[0061] (3) The copper terminal lug coated with aluminum alloy is immersed in a silane coupling agent solution for 10 min, taken out and blown dry, and then placed in a drying oven at 120°C for curing for 2 h to obtain an aluminum alloy-plated copper terminal lug.

[0062] Example 6 This embodiment provides an aluminum alloy-plated copper workpiece and a preparation method thereof. Compared with Embodiment 1, the only difference is that the workpiece is not coated with a silane coating.

[0063] Comparative Example 1 This comparative example provides an aluminum alloy-plated copper workpiece and a preparation method thereof. Compared with Example 5, the only difference is that pure aluminum metal liquid is used instead of aluminum alloy liquid.

[0064] Comparative Example 2 This comparative example provides an aluminum alloy-plated copper workpiece and a preparation method thereof. Compared with Example 5, the only difference is that an equal amount of aluminum is used to replace silicon in the aluminum alloy liquid.

[0065] Comparative Example 3 This comparative example provides an aluminum alloy-plated copper workpiece and a preparation method thereof. Compared with Example 5, the only difference is that an equal amount of aluminum is used to replace magnesium in the aluminum alloy liquid.

[0066] Comparative Example 4 This comparative example provides an aluminum alloy-plated copper workpiece and a preparation method thereof. Compared with Example 5, the only difference is that an equal amount of aluminum is used to replace the rare earth element in the aluminum alloy liquid.

[0067] Test Example 1 The thickness of the aluminum alloy coating or aluminum coating on the copper workpieces prepared in the examples and comparative examples was tested using a Quanta-200 scanning electron microscope (SEM), and the thickness of the silane coating on the copper workpieces prepared in the examples and comparative examples was tested. The obtained data are detailed in Table 1.

[0068] Table 1

[0069] Test Example 2 The copper workpieces prepared in the examples and comparative examples were connected to aluminum cables, and black epoxy resin with a thickness of 90 μm was coated on the connection points to test the voltage drop, pull-off force, and short-time withstand current of the terminal blocks.

[0070] The criteria for voltage drop and pull-off force of the terminal blocks are: pull-off force > 200N, voltage drop ≤ 0.5mV.

[0071] Short-time withstand current: Use JB / T 2436.2-1994 standard, observe the terminal shape after the current is loaded for 1 s.

[0072] The results are shown in Table 2.

[0073] Table 2

[0074] As can be seen from Table 2, the electrical properties and mechanical properties of the final product obtained in the embodiment are better than those of the final product obtained in the comparative example. The final product obtained in the embodiment has a lower voltage and a high pull-off force. After a short-term tolerance, there will be no deformation, welding, fusing, or wire detachment. The final product obtained in the comparative example has a high voltage drop and a low pull-off force. Although there is no deformation or wire detachment, there will be welding and fusing, and the use effect is poor.

[0075] Test Example 3 The copper workpieces prepared in the embodiments and comparative examples were tested for corrosion resistance, strength and wear resistance, and their surface finish and the occurrence of pinhole plating were observed.

[0076] Smoothness: Smoothness is the best if it is even and smooth; roughness with bumps is the second best; and nodule formation is the worst if it has bumps.

[0077] Corrosion resistance: Neutral salt spray is used for evaluation. The salt spray test is carried out in accordance with the national standard "GB / T10125-2012 Artificial atmosphere corrosion test salt spray test". The test temperature is 35±2℃, the NaCl concentration is 50±5 g / L, and the time when the white rust area of ​​the copper workpiece is greater than 5% is recorded. It is required that the white rust area on the surface of the aluminum-plated or aluminum alloy copper workpiece is ≤5% after 120 hours, otherwise the corrosion resistance is judged to be unqualified.

[0078] Strength and wear resistance level: Wear test is carried out with a file under the same conditions, which is divided into three levels: A, B, and C. A is the highest strength, with no peeling or cracking of the coating; B is the second lowest strength, with cracks but no peeling of the coating; C is the lowest strength, with cracks and peeling of the coating.

[0079] Number of pinholes and missed plating: Place the sample under SEM for observation, adjust the focus and magnification, generally the magnification is 100~500 times, carefully observe the cross section of the coating, look for pinholes or missed plating areas, these areas appear as interruptions or voids in the coating, record their number.

[0080] The results are shown in Table 3.

[0081] Table 3

[0082] It can be seen from Table 3 that the final product obtained in the embodiment has good finish, few pinholes, and the number of pinholes is less than 15 / m. 2 The corrosion resistance is good, the time of white rust area> 5% is more than 122h, and the highest can reach 220h, and the strength and wear resistance level are high; while the final product obtained in the comparative example shows that there will be bumps and nodules, and the number of pinholes is 20 / m 2 The above results show that the corrosion resistance is poor, the time for white rust area>5% is within 112 hours, and the strength and wear resistance are low. Among the comparative examples, the comparative example 1 using pure aluminum metal instead of aluminum alloy has the worst effect, and the number of pinholes leaking plating is as high as 52 / m 2 In the corrosion resistance test, the white rust area will be greater than 5% in just 95h. Comparative Example 2 using an equal amount of aluminum to replace silicon, Comparative Example 3 using an equal amount of aluminum to replace magnesium, and Comparative Example 4 using an equal amount of aluminum to replace rare earth elements, although the performance is better than that of Comparative Example 1 of pure aluminum, it is still inferior to the final product obtained in the embodiment. In the aluminum alloy coating of the present invention, each component is indispensable. In the embodiment, the embodiment 1 with 0.1% rare earth element and cerium and lanthanum in a mass ratio of 2:1 and hot dip plating temperature within the preferred range has the best effect, and the number of pinholes leaking is 4 / m 2 In the corrosion resistance test, the white rust area will be greater than 5% after 220 hours, and the strength and wear resistance level can reach A. The hot dip plating temperature of Examples 2 and 3 is within the preferred range, but the rare earth element content is not the preferred 0.1%, and the performance is slightly worse than that of Example 1, and the number of pinholes is 10 / m 2 The preparation parameters of Examples 4 and 5 are not within the preferred range, and the performance is worse than that of Examples 2 and 3, with the number of pinholes being 10 / m 2 As a result, the time required for the white rust area to be greater than 5% was reduced to 125 hours and 122 hours. In Example 6, no silane coating was applied, which resulted in a partial decrease in corrosion resistance.

[0083] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the protection scope of the invention.

Claims

1. An aluminum alloy-plated copper workpiece, characterized in that: It includes a copper workpiece substrate and an aluminum alloy coating coated on the copper workpiece substrate; The aluminum alloy coating comprises, by mass percentage: silicon: 0.1% to 13.0%, magnesium: 0.3% to 5.0%, rare earth elements: 0.1% to 0.4%, and the balance is aluminum and inevitable impurities; the rare earth elements include cerium and lanthanum in a mass ratio of 1:25 to 2:

1.

2. The aluminum alloy-plated copper workpiece according to claim 1, characterized in that: It also includes a silane coating coated on the aluminum alloy coating; the thickness of the silane coating is 1-2 μm; And / or, the thickness of the aluminum alloy coating is 15-80 μm; And / or, the aluminum alloy coating includes, by mass percentage: rare earth elements: 0.1%; The rare earth elements include cerium and lanthanum in a mass ratio of 2:

1.

3. The aluminum alloy-plated copper workpiece according to claim 1, characterized in that: The copper workpiece substrate includes any one of a wiring nose and a transition wire clamp; And / or, when in use, the aluminum alloy-plated copper workpiece is connected to an aluminum conductor, and an organic anti-oxidation layer is coated at the connection between the two.

4. The aluminum alloy-plated copper workpiece according to claim 3, characterized in that: The organic anti-oxidation layer comprises at least one of an epoxy resin layer, a polyurethane layer, a phenolic resin layer, and an acrylic layer; And / or, the thickness of the organic anti-oxidation layer is 10-100 μm; And / or, when the copper workpiece substrate includes a wiring lug, the area of ​​the aluminum alloy coating on the wiring lug accounts for 1% to 25% of the total surface area of ​​the wiring lug.

5. A method for preparing an aluminum alloy-plated copper workpiece according to any one of claims 1 to 4, characterized in that: The steps include: S1: Clean the copper workpiece substrate, put it into a plating agent, take it out, and dry it to obtain a copper workpiece with a plating agent layer; S2: preheating the copper workpiece with the plating-aid layer, and placing it in an aluminum alloy liquid for hot-dip plating to obtain an aluminum alloy-plated copper workpiece.

6. The preparation method according to claim 5, characterized in that: The aluminum alloy liquid includes, by mass percentage, 0.1% to 13.0% silicon, 0.3% to 5.0% magnesium, 0.1% to 0.4% rare earth elements, and the remainder is aluminum and unavoidable impurities; the rare earth elements include cerium and lanthanum in a mass ratio of 1:25 to 2:1; And / or, the hot dip coating temperature is 670-750°C and the time is 4-8 s; And / or, in S1, the plating assistant comprises at least one of NH4Cl solution, ZnCl2 solution, KF solution, and K2ZrF6 solution; And / or, the mass concentration of the plating aid is 0.5% to 12%; And / or, in S2, the preheating temperature is 200-300° C. and the time is 10-30 min; And / or, S2 further includes the steps of immersing the hot-dip plated copper workpiece in a silane coupling agent solution, drying, and curing.

7. The preparation method according to claim 6, characterized in that: The mass concentration of the silane coupling agent solution is 12% to 16%, and the pH is 3 to 5; And / or, the solvent of the silane coupling agent solution includes at least one of anhydrous ethanol, water, and acetic acid; And / or, the soaking time is 8 to 15 min; and / or, the curing temperature is 100-140°C and the curing time is 1.5-3 h; And / or, the hot-dip galvanizing temperature is 680-700°C.

8. The preparation method according to any one of claims 5 to 7, characterized in that: In S1, the cleaned copper workpiece substrate is placed in a plating agent at 30-60° C. for 2-4 minutes; And / or, the plating assistant comprises a KF solution with a mass concentration of 1% to 6%, or a mixed solution of 1.5% to 1.8% KF and 3% to 3.5% NH4Cl, or a mixed solution of 1.5% to 1.8% KF and 5% to 5.5% ZnCl2; And / or, in said S1, cleaning the copper workpiece substrate comprises sequentially performing alkali washing and acid washing on the copper workpiece substrate; And / or, in S1, the drying temperature is 100-140°C; And / or, when used, the method further comprises the step of coating an organic anti-oxidation layer at the connection between the aluminum alloy-plated copper workpiece and the aluminum conductor after the two are connected.

9. The preparation method according to claim 8, characterized in that: In S1, the cleaned copper workpiece substrate is placed in a 2% KF solution at 40-50° C. for 3 min, and then taken out; And / or, the pickling temperature is 40-60°C and the time is 1-3 min; And / or, the acid solution used for pickling includes any one of sulfuric acid, hydrochloric acid and nitric acid; And / or, the concentration of the acid solution used in the pickling is 13-20 g / L; And / or, the pH of the alkaline washing solution used for alkaline washing is 9-12, the alkaline washing temperature is 50-65°C, and the time is 25-35 min.

10. Use of the aluminum alloy-plated copper workpiece according to any one of claims 1 to 4 or the aluminum alloy-plated copper workpiece prepared by the preparation method according to any one of claims 5 to 9 in power lines.

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