Method for enhancing performance of aluminum alloy welding surface

Abstract

The invention discloses a method for enhancing the performance of an aluminum alloy welding surface, and relates to the technical field of aluminum alloy welding. The invention discloses a method for enhancing the performance of an aluminum alloy welding surface. The method comprises the following steps: pretreating an aluminum alloy workpiece; preparing an electrolyte; and the aluminum alloy workpiece is hung in the electrolyte, a power supply anode is connected with the aluminum alloy workpiece through a wire, a cathode is arranged in the electrolyte and does not make contact with the aluminum alloy workpiece, and micro-arc oxidation treatment is conducted on the surface of the aluminum alloy workpiece in a constant-current monopulse mode. The problems that a welding surface is easy to corrode, is not resistant to abrasion and is poor in precision are solved.

Description

Technical Field

[0001] The invention relates to the technical field of aluminum alloy welding, and in particular to a method for enhancing the performance of an aluminum alloy welding surface. Background Art

[0002] Friction stir welding has significant advantages such as the welding surface is not easy to oxidize, the joint quality is good, the operation is simple, and no spark arc and harmful gas are generated during welding. It is widely used in my country's aerospace, shipbuilding, automobile, electronics and other industrial application fields. Its working principle is to use the heat generated by the friction of the workpiece as a heat source, and then use pressure to bond the two workpieces together to complete the welding. However, due to the different types of welding surface materials and the influence of welding temperature, the weld seam with uneven color is presented, which greatly reduces the appearance consistency and appreciation of the welded workpiece, affecting its market value and sales application. Therefore, it is particularly urgent to eliminate the weld seam, intersection line or parting line on the welding surface.

[0003] At present, welding seams are usually beautified by grinding and polishing, chemical corrosion, painting, baking varnish, anodizing and micro-arc oxidation. Among them, grinding and polishing will grind the surface of the workpiece, and chemical corrosion will cause corrosion damage, which will affect the physical properties of the welded parts; the wear resistance, adhesion and high temperature resistance of the welded parts after painting are poor, resulting in a short service life; the baking varnish process is complicated, time-consuming, and costly, and there is also a problem of poor heat dissipation; both anodizing and micro-arc oxidation can form an oxide film on the surface of the welded workpiece, thereby improving the finish and appearance of the welded parts. However, the hardness, corrosion resistance and wear resistance of the workpiece obtained by anodizing are lower than those of the micro-arc oxidation process. This is mainly because anodizing is an oxidation reaction under the action of electric current to generate an oxide film. This process is a chemical reaction, while micro-arc oxidation uses high voltage to generate micro-arc discharge to generate an oxidation reaction on the metal surface to obtain an oxide layer. This process involves chemical reactions, high-temperature plasma reactions, etc. Therefore, the oxide layer has better bonding performance with the substrate, showing more excellent hardness, corrosion resistance and wear resistance.

[0004] Although micro-arc oxidation technology has many advantages, when using the existing micro-arc oxidation process for welding surface treatment, there are still problems such as easy corrosion, lack of wear resistance and poor precision of the welding surface. Therefore, it is urgently necessary to explore a micro-arc oxidation process that can improve the corrosion resistance, wear resistance and high precision of the aluminum alloy welding surface from the aspects of electrolyte type, ratio and power supply parameters. Summary of the invention

[0005] The technical problem to be solved by the present invention is that the existing welding process has the problems that the welding surface is easily corroded, not wear-resistant and has poor precision. The purpose is to provide a method for enhancing the performance of the aluminum alloy welding surface, which solves the problems that the welding surface is easily corroded, not wear-resistant and has poor precision.

[0006] The present invention is achieved through the following technical solutions:

[0007] A method for enhancing the performance of aluminum alloy welding surfaces comprises the following steps:

[0008] Pre-treating the aluminum alloy workpiece;

[0009] Prepare electrolyte;

[0010] The aluminum alloy workpiece is suspended in the electrolyte, the anode of the power supply is connected to the aluminum alloy workpiece through a wire, the cathode is placed in the electrolyte and does not contact the aluminum alloy workpiece, and the surface of the aluminum alloy workpiece is subjected to micro-arc oxidation treatment in a constant current single pulse mode.

[0011] As a possible design, the aluminum alloy includes 2A12, 6061 or 7075.

[0012] As a possible design, the above pretreatment is to clean the aluminum alloy with acid, deionized water and anhydrous ethanol in sequence, and then blow dry it for use.

[0013] As a possible design, the electrolyte includes Na2SiO3 and Na5P3O 10 .

[0014] As a possible design, the electrolyte further includes at least one of Cr2O3, NH4VO3 and NaOH.

[0015] As a possible design, the above electrolyte has a Cr2O3 concentration of 0-20 g / L, a NH4VO3 concentration of 0-10 g / L, a NaOH concentration of 0-5 g / L, a Na2SiO3 concentration of 10-30 g / L, and a Na5P3O 10 The concentration is 5~30g / L.

[0016] As a possible design, the above electrolyte has a Cr2O3 concentration of 0-20 g / L, an NH4VO3 concentration of 5-10 g / L, a NaOH concentration of 4-5 g / L, a Na2SiO3 concentration of 18-25 g / L, and a Na5P3O 10 The concentration is 15-25g / L.

[0017] As a possible design, the power frequency of the micro-arc oxidation treatment is 200-800 Hz, the duty cycle is 10-80%, and the current density is 2-12 A / dm 2 , the reaction time is 10 to 120 minutes.

[0018] As a possible design, the power frequency of the above-mentioned micro-arc oxidation is 300-800 Hz, the duty cycle is 20-70%, and the current density is 3-7 A / dm 2, the reaction time is 70 to 120 minutes.

[0019] As a possible design, the above micro-arc oxidation time is cooled after every 5 minutes until the temperature drops to 15-35°C before starting the next micro-arc oxidation.

[0020] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0021] The present invention pre-treats the surface of the aluminum alloy workpiece to remove impurities and oil stains on the surface, and then performs micro-arc oxidation in a constant current single pulse mode. This can control the growth of the film layer on the surface of the aluminum alloy and ensure that the generated oxide layer is uniform and dense. The voltage will gradually increase with the formation of the film layer, which is helpful to form a more stable oxide film through the micro-arc discharge process. An oxide layer with high consistency and specific color, corrosion resistance and wear resistance can be grown, which greatly improves the corrosion resistance and wear resistance of the welding workpiece and enhances the commercial value of the product.

[0022] In addition, the present invention can make the color of the welding surface uniform, beautify the appearance of the welding surface, and enhance the ornamental value by treating the surface of the aluminum alloy with an electrolyte micro-arc oxidation. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be regarded as limiting the scope. For those of ordinary skill in the art, other relevant drawings can be obtained based on these drawings without creative work. In the drawings:

[0024] Figure 1 The product diagrams of the aluminum alloy before (a) and after (b) micro-arc oxidation treatment of Example 1 of the present invention are shown;

[0025] Figure 2 These are product pictures of the aluminum alloys of Examples 1 to 3 and Example 7 of the present invention after micro-arc oxidation treatment, (a) is Example 2, (b) is Example 1, (c) is Example 3, and (d) is Example 7;.

[0026] Figure 3 This is a 30-day salt spray test result diagram of Example 2 of the present invention;

[0027] Figure 4 This is a friction coefficient curve diagram of Example 3 of the present invention. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with examples and drawings. The illustrative embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention. If specific conditions are not specified in the examples, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0029] Since welds will appear on the existing aluminum alloy welding surfaces, affecting the appearance and performance of the welded workpiece, and the commonly used weld beautification methods cannot improve the performance of the weld surface, the weld surface is prone to corrosion, wear resistance and poor precision.

[0030] Based on the above situation, the present invention provides a method for enhancing the performance of aluminum alloy welding surfaces, by pretreating the aluminum alloy surface and then combining it with constant current single pulse mode micro-arc oxidation treatment to provide corrosion resistance, wear resistance and precision of the welding surface.

[0031] A method for enhancing the performance of aluminum alloy welding surfaces comprises the following steps:

[0032] Pre-treating the aluminum alloy workpiece;

[0033] Prepare electrolyte;

[0034] The aluminum alloy workpiece is suspended in the electrolyte, the anode of the power supply is connected to the aluminum alloy workpiece through a wire, the cathode is placed in the electrolyte and does not contact the aluminum alloy workpiece, and the surface of the aluminum alloy workpiece is subjected to micro-arc oxidation treatment in a constant current single pulse mode.

[0035] The present invention performs welding in a constant current single pulse mode, thereby ensuring that the workpiece surface is not excessively passivated in the early stage of oxidation, and preventing loose film or local ablation caused by excessive current, thereby ensuring that the generated oxide film is denser and more uniform, and improving the welding surface accuracy; by controlling the current rather than the voltage, the energy input can be controlled more smoothly, which is conducive to the uniform growth of the film layer.

[0036] In some embodiments of the present invention, the aluminum alloy includes 2A12, 6061 or 7075.

[0037] In some embodiments of the present invention, the above-mentioned pretreatment is to clean the aluminum alloy with acid, deionized water and anhydrous ethanol in sequence, and then blow dry it for standby use.

[0038] The above acid can be HCl, H2SO4 or other acids.

[0039] In some embodiments of the present invention, the electrolyte includes Na2SiO3 and Na5P3O 10. Micro-arc oxidation is also known as plasma electrolytic oxidation. The micro-arc oxidation process mainly relies on the matching and adjustment of electrolyte and electrical parameters. Under the instantaneous high temperature and high pressure generated by arc discharge, a modified ceramic coating mainly composed of matrix metal oxide and supplemented by electrolyte components grows on the surface of valve metals such as aluminum, magnesium, titanium and their alloys, effectively improving their corrosion resistance and wear resistance. The properties of the film layer obtained by different electrolyte components are also different. The present invention improves the performance of the obtained film layer by selecting a specific metal oxide electrolyte raw material.

[0040] Sodium silicate as an electrolyte will reduce the arc starting voltage, making micro-arc discharge more likely to occur; it will promote the formation of a complete micro-arc oxidation film with planar continuity on the surface of the substrate, while improving the density of the film; the addition of sodium silicate will increase the conductivity of the electrolyte and promote the reaction.

[0041] Sodium phosphate, as an electrolyte, can adjust the pH value in the solution, thereby changing the chemical composition and structure of the passivation coating. It can also destroy the oxide layer on the surface of the clean metal, increase the oxidation rate, and promote the formation of the coating.

[0042] Silicates, phosphates, etc. are the basic electrolytes, which provide necessary ions for the micro-arc oxidation process and participate in the oxidation reaction.

[0043] In some embodiments of the present invention, the electrolyte further includes at least one of Cr2O3, NH4VO3 and NaOH.

[0044] In some embodiments of the present invention, the electrolyte has a Cr2O3 concentration of 0-20 g / L, a NH4VO3 concentration of 0-10 g / L, a NaOH concentration of 0-5 g / L, a Na2SiO3 concentration of 10-30 g / L, and a Na5P3O 10 The concentration is 5~30g / L.

[0045] The concentration of Cr2O3 in the above electrolyte can be any value within the range of 0 to 20 g / L, such as 5 g / L, 8 g / L, 12 g / L, 15 g / L or other arbitrary values; the concentration of NH4VO3 can be any value within the range of 0 to 10 g / L, such as 5 g / L, 8 g / L, 9 g / L, 6 g / L or other arbitrary values; the concentration of NaOH can be any value within the range of 0 to 5 g / L, such as 1.1 g / L, 1.5 g / L, 2.5 g / L, 3.5 g / L or other arbitrary values; the concentration of Na2SiO3 can be any value within the range of 10 to 30 g / L, such as 11 g / L, 15 g / L, 25 g / L, 29 g / L or other arbitrary values; the concentration of Na5P3O 10 The concentration can be any value within the range of 5 to 30 g / L, such as 11 g / L, 15 g / L, 25 g / L, 29 g / L or any other value.

[0046] In some embodiments of the present invention, the electrolyte has a Cr2O3 concentration of 0-20 g / L, a NH4VO3 concentration of 5-10 g / L, a NaOH concentration of 4-5 g / L, a Na2SiO3 concentration of 18-25 g / L, and a Na5P3O 10 The concentration is 15-25g / L.

[0047] In some embodiments of the present invention, the power frequency of the micro-arc oxidation treatment is 200-800 Hz, the duty cycle is 10-80%, and the current density is 2-12 A / dm 2 , the reaction time is 10 to 120 minutes.

[0048] The power frequency is set to 200-800Hz because only at this frequency can a uniform film layer be obtained without bubbles, with high adhesion and density. A frequency that is too low will lead to uneven thickness of the oxide film, difficulty in discharging the electrolyte, and easy generation of bubbles on the surface; while a frequency that is too high will reduce the adhesion and density of the oxide film.

[0049] The duty cycle is set to 10-80% because a high duty cycle will lead to excessive discharge intensity, rapid electrode heating, severe electrode ablation, and a sharp increase in pores and grain boundary defects in the oxide film, which will reduce the quality of the oxide film. A low duty cycle will lead to insufficient discharge intensity, too small micro-arcs, insufficient oxide film thickness, and poor quality.

[0050] Set the current density to 2~12A / dm 2 This is because if the current density is too low, it is not conducive to the passivation of the substrate surface in the initial stage of oxidation, while if the current density is too high, the oxidation will be severe, which can easily lead to loose film or even local ablation, reduced film quality and reduced wear resistance.

[0051] The longer the micro-arc oxidation time is, the better the density of the film is, but its roughness also increases, so the reaction is set to be completed within 10 to 120 minutes.

[0052] The power frequency can be any value within 200-800Hz, such as 300Hz, 400Hz, 500Hz, 700Hz or other arbitrary values; the duty cycle can be any value within 10-80%, such as 20%, 25%, 35%, 45%, 75%, etc.; the current density can be 2-12A / dm 2 Any value within, such as 5A / dm 2 , 8A / dm 2 、9A / dm 2 or 11A / dm 2 ; The reaction time can be any value within 10 to 120 minutes, such as 20 minutes, 30 minutes, 50 minutes, 70 minutes, 80 minutes and 110 minutes.

[0053] In some embodiments of the present invention, the power frequency of the micro-arc oxidation is 300-800 Hz, the duty cycle is 20-70%, and the current density is 3-7 A / dm 2 , the reaction time is 70 to 120 minutes.

[0054] Preferably, the power frequency is 500 Hz, the duty cycle is 20%, and the current density is 4 A / dm 2 , the reaction time is 90min.

[0055] In some embodiments of the present invention, the micro-arc oxidation is cooled after every 5 minutes until the temperature drops to 15-35° C. before starting the next micro-arc oxidation.

[0056] Example 1

[0057] A method for enhancing the performance of aluminum alloy welding surfaces comprises the following steps:

[0058] (1) The 2A12 aluminum alloy substrate is degreased and cleaned by acid, deionized water, and anhydrous ethanol in sequence, and then dried by dry gas for later use. Figure 1 (a)

[0059] (2) Electrolyte preparation: Weigh a certain amount of Cr2O3, NaOH, Na5P3O 10 , Na2SiO3, configured with Cr2O3 concentration of 8g / L, NaOH concentration of 4g / L, Na2SiO3 concentration of 10g / L and Na5P3O 10 Electrolyte with a concentration of 5 g / L;

[0060] (3) Micro-arc oxidation deposition of oxide layer: First, the workpiece is suspended in the electrolyte, and the anode of the power supply is connected to the workpiece through a wire, and the cathode is placed in the electrolyte and does not contact the workpiece; the workpiece surface is micro-arc oxidized using a constant current single pulse mode, where the power frequency is 500 Hz; the duty cycle is 30%; the current density is 6 A / dm 2 ; The reaction time is 60min.

[0061] After micro-arc oxidation treatment, a dark green oxide layer grows on the surface of the welded workpiece, and the weld is completely covered. Figure 1 (b) and Figure 2 (b) as shown.

[0062] Example 2

[0063] A method for enhancing the performance of aluminum alloy welding surfaces comprises the following steps:

[0064] (1) A 2A12 aluminum alloy substrate is degreased and cleaned by acid, deionized water, and anhydrous ethanol in sequence, and then dried by dry gas for later use;

[0065] (2) Electrolyte preparation: Weigh a certain amount of NaOH, Na5P3O 10 and Na2SiO3, with NaOH concentration of 4g / L, Na2SiO3 concentration of 20g / L and Na5P3O 10 Electrolyte with a concentration of 25 g / L;

[0066] (3) Micro-arc oxidation deposition of oxide layer: First, the workpiece is suspended in the electrolyte, and the anode of the power supply is connected to the workpiece through a wire, and the cathode is placed in the electrolyte and does not contact the workpiece; the workpiece surface is micro-arc oxidized using a constant current single pulse mode, where the power frequency is 500 Hz; the duty cycle is 20%; the current density is 4A / dm 2 ; The reaction time is 90min.

[0067] After micro-arc oxidation treatment, a white oxide layer grows on the surface of the 2A12 aluminum alloy substrate. Figure 2 (a) shown.

[0068] Then, the aluminum alloy 2A12 treated in Example 2 and the untreated aluminum alloy 2A12 were placed in a salt spray test box with a sodium chloride concentration of 5% and subjected to a 30-day neutral salt spray test in accordance with the GB / T 10125 salt spray test standard, and then the corrosion of the sample surface was visually observed. The results are as follows: Figure 3 shown.

[0069] Figure 3 (a) is aluminum alloy 2A12 not treated in Example 2, and (b) is aluminum alloy 2A12 treated in Example 2. As can be seen from the figure, after 30 days, the surface of the 2A12 substrate was severely corroded, while the surface of the 2A12 sample after micro-arc oxidation treatment was free of corrosion, indicating that the oxide layer generated by micro-arc oxidation on the surface of the 2A12 aluminum alloy has excellent corrosion resistance.

[0070] Subsequently, the friction performance of the oxide layer grown on the surface of the aluminum alloy 2A12 treated in Example 2 was measured using a ball-on-disc friction and wear tester (MS-T3001), wherein the friction pair selected a GCr15 ball with a radius of 3 mm, a rotation radius of 3 mm, a load of 500 g, a rotation speed of 10 r / min, and a test time of 30 minutes. The average friction coefficient of Example 2 was 0.66.

[0071] Example 3

[0072] It is basically the same as Example 2, except that NH4VO3 is added to the electrolyte, and the concentration of NH4VO3 is 10g / L.

[0073] A method for enhancing the performance of aluminum alloy welding surfaces comprises the following steps:

[0074] (1) A 2A12 aluminum alloy substrate is degreased and cleaned by acid, deionized water, and anhydrous ethanol in sequence, and then dried by dry gas for later use;

[0075] (2) Electrolyte preparation: Weigh a certain amount of NaOH, Na5P3O 10 , NH4VO3 and Na2SiO3, with NaOH concentration of 4g / L, Na2SiO3 concentration of 20g / L, NH4VO3 concentration of 10g / L and Na5P3O 10 Electrolyte with a concentration of 25 g / L;

[0076] (3) Micro-arc oxidation deposition of oxide layer: First, the workpiece is suspended in the electrolyte, and the anode of the power supply is connected to the workpiece through a wire, and the cathode is placed in the electrolyte and does not contact the workpiece; the workpiece surface is micro-arc oxidized using a constant current single pulse mode, where the power frequency is 500 Hz; the duty cycle is 20%; the current density is 4A / dm 2 ; The reaction time is 90min.

[0077] After micro-arc oxidation treatment, a black oxide layer grows on the surface of the 2A12 aluminum alloy substrate. Figure 2 (c) as shown.

[0078] Subsequently, a ball-on-disc friction and wear tester (MS-T3001) was used to measure the friction performance of the oxide layer grown on the surface of the aluminum alloy 2A12 treated in Example 3 and the untreated aluminum alloy 2A12, wherein the friction pair selected a GCr15 ball with a radius of 3 mm, a rotation radius of 3 mm, a load of 500 g, a rotation speed of 10 r / min, and a test time of 30 minutes. The test results are shown in FIG. Figure 4 shown.

[0079] observe Figure 4 It was found that the maximum friction coefficient and average friction coefficient of the 2A12 substrate were 1.87 and 0.82 respectively, while the maximum friction coefficient and average friction coefficient of the 2A12 sample after micro-arc oxidation treatment were only 0.62 and 0.53, indicating that the oxide layer generated by micro-arc oxidation on the surface of 2A12 aluminum alloy has excellent wear resistance. Comparing the average friction coefficients of Example 2 and Example 3, it can be seen that after adding NH4VO3 to the electrolyte, the friction performance of the film layer can be improved.

[0080] Example 4

[0081] This embodiment is basically the same as embodiment 2, except that the current density is 6A / dm 2 .

[0082] A method for enhancing the performance of aluminum alloy welding surfaces comprises the following steps:

[0083] (1) A 2A12 aluminum alloy substrate is degreased and cleaned by acid, deionized water, and anhydrous ethanol in sequence, and then dried by dry gas for later use;

[0084] (2) Electrolyte preparation: Weigh a certain amount of NaOH, Na5P3O 10 and Na2SiO3, with NaOH concentration of 4g / L, Na2SiO3 concentration of 20g / L and Na5P3O 10 Electrolyte with a concentration of 25 g / L;

[0085] (3) Micro-arc oxidation deposition of oxide layer: First, the workpiece is suspended in the electrolyte, and the anode of the power supply is connected to the workpiece through a wire, and the cathode is placed in the electrolyte and does not contact the workpiece; the workpiece surface is micro-arc oxidized using a constant current single pulse mode, where the power frequency is 500 Hz; the duty cycle is 20%; the current density is 6 A / dm 2 ; The reaction time is 90min.

[0086] The friction performance of the oxide layer grown on the surface of the aluminum alloy 2A12 treated in Example 4 was measured using a ball-on-disc friction and wear tester (MS-T3001), where the friction pair selected a GCr15 ball with a radius of 3 mm, a rotation radius of 3 mm, a load of 500 g, a rotation speed of 10 r / min, and a test time of 30 minutes. The average friction coefficient of Example 4 is 0.72, while the average friction coefficient of Example 2 is 0.66. By comparison, it can be seen that the current density is 4A / dm 2 optimal.

[0087] Example 5

[0088] This embodiment is basically the same as Embodiment 2, except that the power frequency is 300 Hz.

[0089] A method for enhancing the performance of aluminum alloy welding surfaces comprises the following steps:

[0090] (1) A 2A12 aluminum alloy substrate is degreased and cleaned by acid, deionized water, and anhydrous ethanol in sequence, and then dried by dry gas for later use;

[0091] (2) Electrolyte preparation: Weigh a certain amount of NaOH, Na5P3O 10and Na2SiO3, with NaOH concentration of 4g / L, Na2SiO3 concentration of 20g / L and Na5P3O 10 Electrolyte with a concentration of 25 g / L;

[0092] (3) Micro-arc oxidation deposition of oxide layer: First, the workpiece is suspended in the electrolyte, and the anode of the power supply is connected to the workpiece through a wire, and the cathode is placed in the electrolyte and does not contact the workpiece; the workpiece surface is micro-arc oxidized using a constant current single pulse mode, where the power frequency is 300 Hz; the duty cycle is 20%; the current density is 4 A / dm 2 ; The reaction time is 90min.

[0093] The friction performance of the oxide layer grown on the surface of the aluminum alloy 2A12 treated in Example 5 was measured by a ball-on-disc friction and wear tester (MS-T3001), wherein the friction pair selected a GCr15 ball with a radius of 3 mm, a rotation radius of 3 mm, a load of 500 g, a rotation speed of 10 r / min, and a test time of 30 minutes. The average friction coefficient of Example 5 was 0.75, while the average friction coefficient of Example 2 was 0.66. By comparison, it can be seen that the power supply frequency is best at 500 Hz.

[0094] Example 6

[0095] This embodiment is basically the same as Embodiment 2, except that the duty cycle is 15%.

[0096] A method for enhancing the performance of aluminum alloy welding surfaces comprises the following steps:

[0097] (1) A 2A12 aluminum alloy substrate is degreased and cleaned by acid, deionized water, and anhydrous ethanol in sequence, and then dried by dry gas for later use;

[0098] (2) Electrolyte preparation: Weigh a certain amount of NaOH, Na5P3O 10 and Na2SiO3, with NaOH concentration of 4g / L, Na2SiO3 concentration of 20g / L and Na5P3O 10 Electrolyte with a concentration of 25 g / L;

[0099] (3) Micro-arc oxidation deposition of oxide layer: First, the workpiece is suspended in the electrolyte, and the anode of the power supply is connected to the workpiece through a wire, and the cathode is placed in the electrolyte and does not contact the workpiece; the workpiece surface is micro-arc oxidized using a constant current single pulse mode, where the power frequency is 500 Hz; the duty cycle is 15%; the current density is 4 A / dm 2 ; The reaction time is 90min.

[0100] The friction performance of the oxide layer grown on the surface of the aluminum alloy 2A12 treated in Example 6 was measured by a ball-on-disc friction and wear tester (MS-T3001), wherein the friction pair selected a GCr15 ball with a radius of 3 mm, a rotation radius of 3 mm, a load of 500 g, a rotation speed of 10 r / min, and a test time of 30 minutes. The average friction coefficient of Example 6 was 0.7, while the average friction coefficient of Example 2 was 0.66. By comparison, it can be seen that the duty cycle is best at 20%.

[0101] Example 7

[0102] A method for enhancing the performance of aluminum alloy welding surfaces comprises the following steps:

[0103] (1) Pre-treating a 2A12 aluminum alloy substrate;

[0104] (2) Electrolyte preparation: Weigh a certain amount of NH4VO3, NaOH, Na5P3O 10 , Na2SiO3, configured with NH4VO3 concentration of 6g / L, NaOH concentration of 4g / L, Na5P3O 10 The electrolyte has a concentration of 25 g / L and a Na2SiO3 concentration of 20 g / L;

[0105] (3) Micro-arc oxidation deposition of oxide layer: First, the workpiece is suspended in the electrolyte, and the anode of the power supply is connected to the workpiece through a wire, and the cathode is placed in the electrolyte and does not contact the workpiece; the surface of the workpiece is micro-arc oxidized using a constant current single pulse mode, where the power frequency is 500 Hz; the duty cycle is 10%; the current density is 6 A / dm 2 ; The reaction time is 15min.

[0106] After micro-arc oxidation treatment, a brown oxide layer grows on the surface of the welded workpiece. Figure 2 (d) as shown.

[0107] Example 8

[0108] This embodiment is basically the same as Embodiment 7, except that the electrolyte further includes Cr2O3.

[0109] A method for enhancing the performance of aluminum alloy welding surfaces comprises the following steps:

[0110] (1) Pre-treating a 2A12 aluminum alloy substrate;

[0111] (2) Electrolyte preparation: Weigh a certain amount of Cr2O3, NH4VO3, NaOH, Na5P3O 10 , Na2SiO3, configured to Cr2O3 concentration of 15g / L, NH4VO3 concentration of 6g / L, NaOH concentration of 4g / L, Na5P3O10 The electrolyte has a concentration of 25 g / L and a Na2SiO3 concentration of 20 g / L;

[0112] (3) Micro-arc oxidation deposition of oxide layer: First, the workpiece is suspended in the electrolyte, and the anode of the power supply is connected to the workpiece through a wire, and the cathode is placed in the electrolyte and does not contact the workpiece; the surface of the workpiece is micro-arc oxidized using a constant current single pulse mode, where the power frequency is 500 Hz; the duty cycle is 10%; the current density is 6 A / dm 2 ; The reaction time is 15min.

[0113] Example 9

[0114] This embodiment is basically the same as the embodiment 8, except that: the power frequency of the micro-arc welding is 800 Hz; the duty cycle is 45%; the current density is 5 A / dm 2 ; The reaction time is 90min.

[0115] A method for enhancing the performance of aluminum alloy welding surfaces comprises the following steps:

[0116] (1) Pre-treating a 2A12 aluminum alloy substrate;

[0117] (2) Electrolyte preparation: Weigh a certain amount of Cr2O3, NH4VO3, NaOH, Na5P3O 10 , Na2SiO3, configured to Cr2O3 concentration of 15g / L, NH4VO3 concentration of 6g / L, NaOH concentration of 4g / L, Na5P3O 10 The electrolyte has a concentration of 25 g / L and a Na2SiO3 concentration of 20 g / L;

[0118] (3) Micro-arc oxidation deposition of oxide layer: First, the workpiece is suspended in the electrolyte, and the anode of the power supply is connected to the workpiece through a wire, and the cathode is placed in the electrolyte and does not contact the workpiece; the workpiece surface is micro-arc oxidized using a constant current single pulse mode, where the power frequency is 800 Hz; the duty cycle is 45%; the current density is 5 A / dm 2 ; The reaction time is 90min.

[0119] Example 10

[0120] This embodiment is basically the same as Embodiment 7, except that the aluminum alloy is 7075.

[0121] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for enhancing the performance of aluminum alloy welding surfaces, characterized in that: The steps include: Pre-treating the aluminum alloy workpiece; Prepare electrolyte; The aluminum alloy workpiece is suspended in the electrolyte, the anode of the power supply is connected to the aluminum alloy workpiece through a wire, the cathode is placed in the electrolyte and does not contact the aluminum alloy workpiece, and the surface of the aluminum alloy workpiece is micro-arc oxidized in a constant current single pulse mode.

2. A method for enhancing the performance of aluminum alloy welding surfaces according to claim 1, characterized in that: The aluminum alloy includes 2A12, 6061 or 7075.

3. The method for enhancing the performance of aluminum alloy welding surfaces according to claim 1, characterized in that: The pretreatment is to clean the aluminum alloy with acid, deionized water and anhydrous ethanol in sequence, and then blow dry for standby use.

4. The method for enhancing the performance of aluminum alloy welding surfaces according to claim 1, characterized in that: The electrolyte includes Na2SiO3 and Na5P3O 10 .

5. A method for enhancing the performance of aluminum alloy welding surfaces according to claim 4, characterized in that: The electrolyte also includes at least one of Cr2O3, NH4VO3 and NaOH.

6. A method for enhancing the performance of aluminum alloy welding surfaces according to claim 5, characterized in that: The electrolyte has a Cr2O3 concentration of 0-20 g / L, an NH4VO3 concentration of 0-10 g / L, a NaOH concentration of 0-5 g / L, a Na2SiO3 concentration of 10-30 g / L, and a Na5P3O 10 The concentration is 5~30g / L.

7. A method for enhancing the performance of aluminum alloy welding surfaces according to claim 6, characterized in that: The electrolyte has a Cr2O3 concentration of 0-20 g / L, an NH4VO3 concentration of 5-10 g / L, a NaOH concentration of 4-5 g / L, a Na2SiO3 concentration of 18-25 g / L, and a Na5P3O 10 The concentration is 15-25g / L.

8. The method for enhancing the performance of aluminum alloy welding surfaces according to claim 1, characterized in that: The power frequency of the micro-arc oxidation treatment is 200-800 Hz, the duty cycle is 10-80%, and the current density is 2-12 A / dm 2 , the reaction time is 10 to 120 minutes.

9. A method for enhancing the performance of aluminum alloy welding surfaces according to claim 8, characterized in that: The power frequency of the micro-arc oxidation is 300-800 Hz, the duty cycle is 20-70%, and the current density is 3-7 A / dm 2 , the reaction time is 70 to 120 minutes.

10. The method for enhancing the performance of aluminum alloy welding surfaces according to claim 1, characterized in that: The micro-arc oxidation was cooled after every 5 minutes until the temperature dropped to 15-35° C. before starting the next micro-arc oxidation.

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