JPS6013272B2 - Improved aluminum busbar manufacturing method - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for manufacturing an aluminum busbar.

In particular, the present invention relates to a plating method for producing aluminum busbars with improved electrical contact at the conductor connections and at the contact surfaces with the plugs. Note that the term "aluminum" used in this specification means aluminum and its alloys. Conventionally, steel conductors have been used in busbars, but due to the instability of copper resources, supply, and prices, a shift to aluminum conductors is underway. However, when using aluminum busbars, there are concerns such as corrosion at the connection with the copper conductor and an increase in contact resistance at the contact surface with the copper or aluminum conductor. is being painted. In addition, in order to omit this kind of work and prevent accidents due to work errors, the connection parts of aluminum busbars are usually zincate treated, then copper-plated, and then tin or It is plated with silver. Aluminum busbars plated with tin or silver using the zincate method can be used without special treatment prior to construction in locations where they are not exposed to significant corrosive atmospheres or high temperatures. However, the conventional method requires a very large number of plating steps, as shown in Comparative Example 1 below. In addition, in the conventional method, since the copper strike and base plating layer are used, once the aluminum substrate and/or the zinc substitution layer are exposed, the aluminum or zinc will be severely corroded due to contact corrosion with the copper, and the plating will be damaged. It has the disadvantage of swelling. In addition, if the plug is used in a highly corrosive environment or at high temperatures, or if the plug becomes loose or the bolts are not properly installed vertically when connecting to other conductors, the resistance of the contact increases and overheating occurs. There is a risk of Another drawback of the conventional method is that the copper coating solution used is strongly alkaline on the laminar layer, so if there is even the slightest defect in the zincate layer, the aluminum will dissolve from there, causing the copper coating to deteriorate. The problem is that the plating layer swells during cleaning, which is a defect. Furthermore, the conventional method has the disadvantage that the plating solution contains highly toxic cyanide. In view of the above-mentioned drawbacks of the conventional methods, the object of the present invention is to provide a method for manufacturing aluminum busbars that does not have any of these drawbacks.

That is, in the present invention, as a pretreatment for nickel plating,
Etching is carried out with a solution containing 5-35% hydrochloric acid, and then 1 nickel is removed from a plating solution containing nickel ions in the form of sulfamate or fluoride at 50% or more.
The present invention relates to a method for manufacturing an aluminum busbar, characterized in that nickel plating is applied directly to the connecting portions of the conductors and the contact surfaces of the plugs at a rate of ~50 o/s.

In the method for manufacturing an aluminum busbar according to the present invention, first, the connecting portion of the busbar is prepared using a solution containing 5 to 35% hydrochloric acid, preferably 10 to 20% hydrochloric acid, and 0.5 to 1% nitric acid and/or sulfuric acid. , etching for 5 seconds to 2 minutes, preferably 3 minutes to 1 minute.

Thereafter, it is washed with water and plated with a nickel sulfamate plating solution or a nickel fluoroborate plating solution containing 50/or more nickel ions. The structure of the aluminum busbar according to the present invention is such that, in its support part, nickel is coated on aluminum having significant microscopic irregularities at a ratio of 1 to 50 parts/cm, preferably 5 to 20 parts/cm. It is directly attached. If the hydrochloric acid is less than 5% or the etching time is less than 5 seconds, the entire surface will not be etched, the plating will be uneven, and when used as a Fussbar, the corrosion resistance will be poor and the contact resistance will be high.

If the hydrochloric acid content is more than 35%, gas will be generated significantly, and if the etching time is more than 2 minutes, the production rate will be slow, and if the etching time is less than 50% nickel ion, the desorption rate will be slow and the plating time will be too long, making it difficult to actually use it. It cannot be applied in the operation of Plating solutions other than nickel sulfamate plating baths or nickel borosulfide plating baths do not adhere well to the plating solution and cannot be used as busbars. Nickel plating amount 1 female'
Below this, there is a problem in terms of corrosion resistance when using it as a bus bar, and when it is above 9/50, a large amount of nickel, which is more expensive than aluminum, will be used, resulting in an excessively high cost. In a specific implementation of the present invention, an aluminum plate manufactured by rolling or extrusion is cut into a desired size, and then polished, degreased, etc. are performed as necessary, and then the joints are etched with alkali. As the alkaline etching solution, for example, a solution of caustic soda, soda carbonate, etc. is used, and in some cases,
A solution containing a surfactant such as sodium gluconate is used. Next, it is washed with water, and the subsequent part is etched with the aforementioned solution containing 5 to 35% hydrochloric acid, and then washed with water and nickel plated. Normally, in order to treat only the connection surface, etching and plating are performed by immersing only the connection surface in liquid, but for the same purpose, parts other than the connection portion are coated in advance with paint, vinyl tape, rubber, etc. You can leave it for the evening. The nickel sulfamate plating solution preferably contains nickel chloride and boric acid in addition to nickel sulfamate, and the nickel borofluoride plating solution preferably contains boric acid in addition to nickel borofluoride. Furthermore, the production of aluminum busbars according to the method of the present invention can be operated manually, semi-automatically or automatically. As shown in Example 1 below, the method of the present invention has a significantly shorter number of steps than the conventional method and does not use any cyanide.

In addition, since nickel is plated directly onto the aluminum surface, even if the aluminum base is exposed, contact corrosion is much less than that of products manufactured using the conventional method. Further, since nickel has superior oxidation resistance compared to copper and is less likely to interdifuse with aluminum, the phenomenon of contact resistance increasing significantly during use at high temperatures as in conventional methods does not occur. Further, as a result of a current cycle test, it was found that the aluminum push bar manufactured by the method of the present invention has very stable contact resistance. This seems to have something to do with the fact that in the manufacturing method, when etching aluminum, significant unevenness is created, and even when plating is applied on top of it, significant unevenness occurs on the surface of the plating. Details are not clear. Next, examples of the present invention will be described. Example 1 A bare conductor three-pole feeder bus duct was manufactured from an extruded AI060-F aluminum plate with a thickness of IQ, a width of 20 m, and a length of 5 m.

At that time, after the conductor is extruded, the connection part is soaked with caustic soda for 30 minutes.
Well, with a solution of 6,000 ml consisting of 30 tbsp of soda carbonate, 1
Etched for minutes, washed with water, then hydrochloric acid 16%, nitric acid 1%
Etched for 1 minute with a solution consisting of Nj (S
03N ratio) 2.4L0320 evening/so, NiC] 2. Mother was immersed in a plating solution at 50℃ consisting of 〇15ta' evening, day 380330 evening/so, and plated for 5 minutes at a current density of 5A/d〆. As a result, a nickel plating of approximately 4.6 mm was obtained. A patch plate made of the same material with a thickness of IQ, a width of 20 and a length of 15Q was also plated with nickel to a thickness of about 4.69/cm using the same method. This patch plate was inserted between each conductor of two sets of bus ducts, and the connections were made using galvanized steel bolts, nuts, and washers.

600V while measuring the temperature of the connection using a thermocouple.
A current of 3000 A was applied for 45 minutes, and the current was stopped for 45 minutes. When this was repeated 1000 cycles, the maximum temperature increase was 3000°C, which was very small. Example 2 A tapped bus duct was manufactured from an AI060-day 14 rolled aluminum plate with a thickness of 4 sides, a width of 25 mm, and a length of 2 mm.

After rolling, straightening and cutting, it was washed with trichloroethylene, and the tap part was etched for 2 minutes with a solution of 50 qo of caustic soda and 3 gluconate, washed with water, and washed with 15% hydrochloric acid and sulfuric acid. After etching with a solution containing 0.5%, washing with water and using the same plating solution as in Example 1.
One female was plated at a normal temperature of 50° C. and a current density of 8 A/d, and approximately 14.6 females/base nickel plating was performed. A 26-bar vinyl copper-covered wire was connected to the tap using a brass terminal screw, and a current of 5 times was applied. Maximum temperature rise is 27
It was small at q0. Example 3 A bus duct adapter made of AI060 aluminum rolled plate having a thickness of 0.8 mm, a width of 10 arcs, and a length of 0.5 m was manufactured.

Wash 7 skins from both ends with trichlorethylene and wash for 50 minutes.
Etched for 1 minute with 60 oo solution containing caustic soda, washed with water, etched with 18% hydrochloric acid solution,
Plating was carried out for 2 minutes at a current density of 10 A'd with a plating solution consisting of the following: nickel plating of approximately 3.7 9/base.

A salt water fog test was conducted at 35° C. for 7 hours using 15% NaC, but no corrosion occurred. Comparative Example 1 A bus duct of the same type as Example 1 was manufactured using a conventional method.

However, the surface treatment of the connection part is done by the conventional zincate method, and after extrusion, caustic soda 302/so, soda carbonate 30/
Etched with a 60qo solution consisting of 300 ml of water, washed with water, immersed in a 50% nitric acid solution for 1 hour, and etched with Na 0 days.
525 evening/SoZn〇
100 min. / zincate treatment by immersing in the solution for 1 minute, washing with water, plating with a current density of 2.6A'd at 4 pins for 1 minute from cyanide steel strike plating, washing with water, then cyanide. 4A/ from steel plating solution (89qo)
Plating was carried out for 5 minutes using a stannate layer, and then a 5-step tin plating was applied thereon.

A backing plate made of the same material and having the same shape as in Example 1 was also plated with tin by the zincate method. These bus ducts and accessories include: When tested in the same manner as in Example 1, the maximum temperature increase reached 12,030. Comparative Example 2 An adapter of the same type as in Example 3 was manufactured.

Comparative Example 1 on 7 skins from both ends after washing with trichlorethylene
The same etching, pickling, zincate treatment, and copper strike plating were applied as in Example 3, and nickel plating was applied thereon in the same manner and for the same time as in Example 3. When the same salt spray test as in Example 3 was conducted, blistering occurred at a rate of 14 degrees. As described above, the present invention provides an inexpensive aluminum bus bar with stable electrical contact resistance and excellent corrosion resistance, and has great industrial application value.

Claims (1)

[Claims] 1. As a pretreatment for nickel plating, etching is performed with a solution containing 5 to 35% hydrochloric acid, and then 50 g/l of nickel ions are added as sulfamate or borofluoride.
1 to 50 mg/cm of nickel from the above-containing metsuki liquid
A method for manufacturing an aluminum busbar, characterized in that nickel plating is applied directly to the connection part of the conductor and the contact surface of the plug at a ratio of 2:2.