Bus bar and bottoming copper plating method thereof

Abstract

The invention discloses a bus bar and a bottoming copper plating method thereof, and the bottoming copper plating method for the bus bar sequentially comprises the steps of alkali washing, first-time water washing, acid pickling, second-time water washing, water film continuity inspection and cyanide-free alkaline copper plating, and after the copper plating step is completed, tin plating can be carried out on the bus bar. The method route has the advantages of being safe and non-toxic, the surface roughness of the bus bar after cyanide-free alkaline copper plating is high, the bus bar serves as a bottoming copper layer, and due to the use of the hanging tool, the surface of the bus bar is free of clamp marks, and a plating layer is flat and has high adhesion performance.

Description

Technical Field

[0001] The invention belongs to the technical field of aerospace fasteners, and in particular relates to a bus bar and a base copper plating method thereof. Background Art

[0002] In the field of aerospace, busbar steel materials are widely used after being plated with base copper and then tinned. They have good weldability, achieve reliable connection, and achieve the purpose of stabilizing the product. The coating increases the corrosion resistance of the parts and can be used to tighten the connection in acidic and alkaline environments. In the early busbar copper plating methods, the cyanide used in cyanide copper plating is a highly toxic substance, which is dangerous to on-site processing personnel, and the sewage treatment is difficult and the environmental damage is serious. In addition, the busbar parts are relatively small, and the existing tooling fixtures are tied in a binding manner, so that the surface of the busbar has tooling fixture marks after copper plating, and the coating is incomplete, affecting its performance. Therefore, a safe and non-toxic copper plating method and a hanger that can keep the busbar coating intact are needed.

[0003] The patent document with the announcement number CN102978669A discloses an environmentally friendly electroplating copper solution, which is composed of the following components: main binder: disodium ethylenediaminetetraacetate or dipotassium ethylenediaminetetraacetate; auxiliary binder: trisodium citrate, tripotassium citrate or sodium potassium tartrate; main salt: copper sulfate or basic copper carbonate; conductive salt: sodium nitrate or potassium nitrate; pH value adjuster: sodium hydroxide or potassium hydroxide. The electroplating copper solution is a cyanide-free plating solution, but lacks a surface treatment process. If the surface of the plated part is relatively smooth or there are many impurities, the electroplating process is carried out without surface treatment, which is easy to affect the bonding quality between the coating and the plated part. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a busbar and a method for plating a base copper thereon.

[0005] The present invention is achieved through the following technical solutions.

[0006] A busbar provided by the present invention comprises a busbar body and a connecting portion, wherein one end of the busbar body is connected to the connecting portion, a first through hole is arranged at the other end of the busbar body, and a second through hole is arranged at the connecting portion.

[0007] Preferably, the busbar body and the connecting portion are arranged vertically, and the busbar body is arranged in a curved shape on a side close to the through hole.

[0008] A method for plating base copper on a busbar comprises the steps of alkali washing, first water washing, acid washing, second water washing, water film continuity inspection and cyanide-free alkaline copper plating.

[0009] Preferably, the alkali washing step comprises washing the busbars at a temperature of 60 to 80° C. after mixing 30 to 50 g / L of sodium hydroxide, 20 to 30 g / L of sodium phosphate, 20 to 30 g / L of sodium carbonate and 3 to 5 g / L of sodium silicate.

[0010] Preferably, the first water washing and the second water washing steps are to wash the busbars at room temperature, and the acid washing step includes washing the busbars at room temperature using 100-300 g / L of hydrochloric acid.

[0011] Preferably, the cyanide-free alkaline copper plating step comprises using potassium hydroxide solution to adjust the pH of the copper sulfate additive bath solution, then adding sodium hydroxide, and performing cyanide-free alkaline copper plating after fixing the busbar with a hanger.

[0012] Preferably, the cyanide-free alkaline copper plating step includes using potassium hydroxide solution to adjust the pH of the bath solution containing 250-300 g / L of copper sulfate additive to 8-9, then adding sodium hydroxide, the sodium hydroxide content is 1-4 g / L, and fixing the busbar with a hanger at a temperature of 55-60°C to perform cyanide-free alkaline copper plating, and performing tin plating after completing the cyanide-free alkaline copper plating.

[0013] Preferably, the hanger comprises a connecting rod, a hook and a fixed fin, one end of the connecting rod is connected to the hook, the connecting rod is connected to the fixed fin, and the fixed fin is connected to the bus bar.

[0014] Preferably, the tinning treatment step comprises tinning the busbar at a temperature of 70-85° C. using 20-80 g / L sodium stannate, 10-15 g / L sodium hydroxide, 12-30 g / L sodium acetate, and 0.3-0.5 g / L hydrogen peroxide.

[0015] Preferably, in the water film continuity check, the water film needs to remain unbroken for at least 30 seconds.

[0016] The beneficial effects of the present invention are:

[0017] The method route of the present invention is safe and non-toxic. The roughness of the busbar surface after cyanide-free alkaline copper plating is relatively high. The copper layer is used as a base, and the use of a hanger ensures that the busbar surface has no clamp marks, and the plating layer is flat and has high adhesion performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the main structure of the busbar;

[0019] Figure 2 is a schematic diagram of the side view structure of the busbar;

[0020] Figure 3 It is a structural schematic diagram of the hanger of the present invention in use state;

[0021] Figure 4 It is a schematic diagram of the main structure of the hanger of the present invention;

[0022] Figure 5 It is a side view structural schematic diagram of the hanger of the present invention;

[0023] In the figure: 1-busbar body, 2-connecting portion, 3-first through hole, 4-second through hole, 5-connecting rod, 6-hook, 7-fixing fin. DETAILED DESCRIPTION

[0024] The technical solution of the present invention is further described below, but the scope of protection claimed is not limited to the description.

[0025] Embodiment 1:

[0026] like Figures 1 to 5 As shown, a busbar comprises a busbar body 1 and a connecting portion 2, wherein one end of the busbar body 1 is connected to the connecting portion 2, a first through hole 3 is arranged at the other end of the busbar body 1, and a second through hole 4 is arranged at the connecting portion 2.

[0027] The busbar body 1 and the connecting portion 2 are arranged vertically, and the busbar body 1 is arranged in a curved shape on one side close to the through hole 3 .

[0028] A method for plating base copper on a busbar comprises the steps of alkali washing, first water washing, acid washing, second water washing, water film continuity inspection and cyanide-free alkaline copper plating.

[0029] Alkaline cleaning is mainly used to remove oil stains on the surface of parts;

[0030] The first water washing is mainly to clean the busbar surface with alkali solution;

[0031] Pickling is for lightening effect;

[0032] The second water washing is mainly to clean the acid on the surface of the parts;

[0033] The water film continuity check is used to verify whether the surface of the part is completely cleaned;

[0034] After cyanide-free alkaline copper plating, the surface roughness of the parts is relatively high, which provides a significant effect in increasing the adhesion of the tin layer in the subsequent tin plating process. After cyanide-free alkaline copper plating, a third water wash is required, mainly to clean the copper plating residue on the surface of the parts.

[0035] The alkali washing step includes using 30 g / L of sodium hydroxide, 20 g / L of sodium phosphate, 20 g / L of sodium carbonate, and 3 g / L of sodium silicate to wash the busbar at a temperature of 60°C.

[0036] The first water washing and the second water washing steps are for washing the busbars at room temperature, and the acid washing step includes washing the busbars at room temperature using 100 g / L hydrochloric acid.

[0037] The cyanide-free alkaline copper plating step comprises using potassium hydroxide solution to adjust the pH of a bath solution containing a copper sulfate additive, adding sodium hydroxide, and performing cyanide-free alkaline copper plating after fixing the busbar with a hanger.

[0038] The cyanide-free alkaline copper plating step includes using potassium hydroxide solution to adjust the pH of the bath solution containing 250g / L of copper sulfate additive to 8, then adding sodium hydroxide with a sodium hydroxide content of 1g / L, fixing the busbar with a hanger at a temperature of 55°C, and then performing cyanide-free alkaline copper plating. After completing the cyanide-free alkaline copper plating, tin plating is performed.

[0039] The hanger includes a connecting rod 5, a hook 6 and a fixed fin 7. One end of the connecting rod 5 is connected to the hook 6, the connecting rod 5 is connected to the fixed fin 7, and the fixed fin 7 is connected to the bus bar. The connecting rod 5 and the hook 6 are made of carbon steel material and have conductive ability. The hook 6 is used to hang the hanger on the processing equipment.

[0040] The thickness of the fixed fin 7 is 2 mm, which is thin and thus has a certain degree of deformability. Several layers of fixed fins 7 are arranged along the vertical direction of the connecting rod 5. Each layer of fixed fins 7 is symmetrically arranged with the connecting rod 5 as the center. The two fixed fins 7 are simultaneously extended into the second through hole 4 of the same busbar. Since there is a gap between the two fixed fins 7, the two fixed fins 7 are in a bent state after extending into the second through hole 4. The two fixed fins 7 have a force tending to move away from each other, so the busbar is fixed under the elastic force of the two fixed fins 7. The fixed fins 7 are triangular, and both ends can fix the busbar.

[0041] The tin plating step includes tinning the busbars at a temperature of 70° C. using 20 g / L sodium stannate, 10 g / L sodium hydroxide, 12 g / L sodium acetate, and 0.3 g / L hydrogen peroxide.

[0042] The water film continuity check is performed by creating a water film on the busbar surface and maintaining the water film for 30 seconds without breaking.

[0043] Embodiment 2:

[0044] A busbar and a method for plating base copper therefor are basically the same as those in Example 1, except that:

[0045] The alkali washing step includes using 35 g / L of sodium hydroxide, 22 g / L of sodium phosphate, 21 g / L of sodium carbonate, and 3 g / L of sodium silicate to wash the busbar at a temperature of 65°C.

[0046] The pickling step includes cleaning the busbars at room temperature using 150 g / L of hydrochloric acid.

[0047] The cyanide-free alkaline copper plating step includes using potassium hydroxide solution to adjust the pH of the bath solution containing 260 g / L of copper sulfate additive to 8, then adding sodium hydroxide with a sodium hydroxide content of 2 g / L, and fixing the busbar with a hanger at a temperature of 56°C to perform cyanide-free alkaline copper plating.

[0048] The tinning treatment step includes tinning the busbars at a temperature of 75° C. using 30 g / L sodium stannate, 11 g / L sodium hydroxide, 16 g / L sodium acetate, and 0.3 g / L hydrogen peroxide.

[0049] Embodiment 3:

[0050] A busbar and a method for plating base copper therefor are basically the same as those in Example 1, except that:

[0051] The alkali washing step includes using 40 g / L of sodium hydroxide, 24 g / L of sodium phosphate, 25 g / L of sodium carbonate, and 4 g / L of sodium silicate to wash the busbar at a temperature of 70°C.

[0052] The pickling step includes cleaning the busbars at room temperature using 200 g / L hydrochloric acid.

[0053] The cyanide-free alkaline copper plating step includes using potassium hydroxide solution to adjust the pH of the bath solution containing 270 g / L of copper sulfate additive to 8.5, then adding sodium hydroxide with a sodium hydroxide content of 3 g / L, and fixing the busbar with a hanger at a temperature of 57°C to perform cyanide-free alkaline copper plating.

[0054] The tinning treatment step includes tinning the busbars at a temperature of 75° C. using 40 g / L sodium stannate, 12 g / L sodium hydroxide, 20 g / L sodium acetate, and 0.4 g / L hydrogen peroxide.

[0055] Embodiment 4:

[0056] A busbar and a method for plating base copper therefor are basically the same as those in Example 1, except that:

[0057] The alkali washing step includes using 45 g / L sodium hydroxide, 27 g / L sodium phosphate, 27 g / L sodium carbonate, and 5 g / L sodium silicate to mix and then wash the busbar at a temperature of 75°C.

[0058] The pickling step includes cleaning the busbars at room temperature using 100 to 300 g / L of hydrochloric acid.

[0059] The cyanide-free alkaline copper plating step includes using potassium hydroxide solution to adjust the pH of the bath solution containing 280 g / L of copper sulfate additive to 9, then adding sodium hydroxide with a sodium hydroxide content of 3 g / L, and fixing the busbar with a hanger at a temperature of 59°C to perform cyanide-free alkaline copper plating.

[0060] The tinning treatment step includes tinning the busbars at a temperature of 80° C. using 65 g / L sodium stannate, 14 g / L sodium hydroxide, 25 g / L sodium acetate, and 0.5 g / L hydrogen peroxide.

[0061] Embodiment 5:

[0062] A busbar and a method for plating base copper therefor are basically the same as those in Example 1, except that:

[0063] The alkali washing step includes using 50 g / L of sodium hydroxide, 30 g / L of sodium phosphate, 30 g / L of sodium carbonate, and 5 g / L of sodium silicate to wash the busbar at a temperature of 60 to 80°C.

[0064] The pickling step includes cleaning the busbars at room temperature using 300 g / L hydrochloric acid.

[0065] The cyanide-free alkaline copper plating step includes using potassium hydroxide solution to adjust the pH of the bath solution containing 300 g / L of copper sulfate additive to 9, then adding sodium hydroxide with a sodium hydroxide content of 4 g / L, and fixing the busbar with a hanger at a temperature of 60°C and then performing cyanide-free alkaline copper plating.

[0066] The tinning treatment step includes tinning the busbars at a temperature of 85° C. using 80 g / L sodium stannate, 15 g / L sodium hydroxide, 30 g / L sodium acetate, and 0.5 g / L hydrogen peroxide.

[0067] The 30CrMnSiA busbars prepared in Examples 1-5 were tested according to GB / T 5270. The process included selecting 50 busbars from the same batch in Examples 1-5, heating them and then quenching them to test the coating conditions of the busbars. The results are shown in the following table.

[0068]

[0069] The busbar coatings prepared in Examples 1-5 showed no abnormalities and met the use standards.

Claims

1. A bus bar, characterized in that: The busbar body (1) comprises a busbar main body (1) and a connecting portion (2), wherein one end of the busbar main body (1) is connected to the connecting portion (2), the other end of the busbar main body (1) is provided with a first through hole (3), and the connecting portion (2) is provided with a second through hole (4).

2. A busbar according to claim 1, characterized in that: The busbar body (1) and the connecting portion (2) are arranged vertically, and the busbar body (1) is arranged in a curved manner on the side close to the through hole (3).

3. A method for plating base copper on a busbar as claimed in any one of claims 1 to 2, characterized in that: The process includes alkaline washing, first water washing, acid washing, second water washing, water film continuity inspection, and cyanide-free alkaline copper plating steps.

4. A method for plating a base copper on a busbar as claimed in claim 3, characterized in that: The alkali washing step includes using 30-50 g / L of sodium hydroxide, 20-30 g / L of sodium phosphate, 20-30 g / L of sodium carbonate, and 3-5 g / L of sodium silicate to wash the busbar at a temperature of 60-80°C.

5. A method for plating a base copper on a busbar as claimed in claim 3, characterized in that: The first water washing and the second water washing steps are for washing the busbars at room temperature, and the acid washing step includes washing the busbars at room temperature using 100-300 g / L of hydrochloric acid.

6. A method for plating a base copper on a busbar as claimed in claim 3, characterized in that: The cyanide-free alkaline copper plating step comprises using potassium hydroxide solution to adjust the pH of a bath solution containing a copper sulfate additive, adding sodium hydroxide, and performing cyanide-free alkaline copper plating after fixing the busbar with a hanger.

7. A method for plating a base copper on a busbar as claimed in claim 6, characterized in that: The cyanide-free alkaline copper plating step includes using potassium hydroxide solution to adjust the pH of the bath solution containing 250-300 g / L of copper sulfate additive to 8-9, then adding sodium hydroxide with a sodium hydroxide content of 1-4 g / L, fixing the busbar with a hanger at a temperature of 55-60°C, and then performing cyanide-free alkaline copper plating. After completing the cyanide-free alkaline copper plating, tin plating is performed.

8. A method for plating a base copper on a busbar as claimed in claim 6, characterized in that: The hanger comprises a connecting rod (5), a hook (6) and a fixed fin (7); one end of the connecting rod (5) is connected to the hook (6); the connecting rod (5) is connected to the fixed fin (7); and the fixed fin (7) is connected to the bus bar.

9. A method for plating a base copper on a busbar as claimed in claim 7, characterized in that: The tinning treatment step includes tinning the busbar at a temperature of 70 to 85° C. using 20 to 80 g / L of sodium stannate, 10 to 15 g / L of sodium hydroxide, 12 to 30 g / L of sodium acetate, and 0.3 to 0.5 g / L of hydrogen peroxide.

10. A method for plating base copper on a busbar as claimed in claim 3, characterized in that: In the water film continuity check, the water film needs to remain unbroken for at least 30 seconds.

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