JPS60224735A - Conductor material - Google Patents

Abstract

PURPOSE:To obtain an Al as an electrically conductive material having superior suitability to zincate treatment before plating and superior adhesion to a plated film by adding specified elements to an Al alloy as an electrically conductive material. CONSTITUTION:The electrically connecting part of an Al alloy plate or the like as an electrically conductive material is plated with Cu, Sn or the like so as to reduce the contact resistance. Since the resulting plated film is required to have superior adhesion to the Al alloy to prevent stripping, an Al alloy contg. >=99.6wt% Al and 0.03-0.08wt% at least two among Zn, Cu, Ni and Sn as elements which are electrically nobler than Al in an alkaline bath and reduce cathodic polarization is used. The connecting part of the Al alloy is etched with an aqueous NaOH soln. to remove oil and an oxide film from the surface, and the part is neutralized with an acid, cleaned, and subjected to zincate treatment. The treated part is plated with Cu, Sn or the like to form a plated film having superior adhesion.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a conductive material, and particularly to a conductive material whose electrical connection portions are subjected to zinc substitution treatment and then subjected to steel plating, tin plating, etc.

[Prior art and seven problems]

Generally, conductive materials are required to have a conductivity of 61% or more, and for example, aluminum materials with a conductivity of 99.60 wt% or more are used as specified in JIS (4180). It is made by forming an aluminum material with a purity of .60 Wi% or higher by rolling, extrusion, etc., and then cutting it into predetermined dimensions.

Before such a conductive material is connected to a predetermined portion, the electrical connection portion is plated with copper, tin, etc.

However, in such a process, as a pretreatment for the plating process, the surface of the conductor material is etched with caustic soda, etc. to remove the oil and oxide film on the surface, and after etching, it is washed with water, neutralized with a nitric acid or hydrofluoric acid bath, etc. After the treatment and washing with water again, zinc substitution treatment (zincate treatment) is performed, and then copper plating, tin plating, etc. are performed.

In such cases, in the past, since the formation of a zincate film was rough and large, the plating film could peel off after plating, or in severe cases, the zincate film itself could peel off, so double zincate treatment, Treatments such as triple zincate treatment may have to be carried out.

Furthermore, even if such multi-zincate treatment is performed, rice-grain-sized or azuki-bean-sized blisters may occur on the cut end surface after plating, and in such cases, the plating film deteriorates over time. There is a problem that adhesion deteriorates.

[Disclosure of the invention]

As a result of research into the causes of poor zincating properties and plating properties, the present inventor found that surface treatment conditions, i.e. pretreatment conditions such as etching amount, zincate treatment conditions such as ZnO and NaOH concentrations and additives, and Cu strike plating such as pH and temperature. It was found that the degree of defectiveness differs depending on the conditions.

However, simply setting the surface treatment conditions to the optimum values is not perfect, and some users find it difficult to change the surface treatment conditions that have been used up until now. Rather than trying to improve the zincating properties and plating properties through surface treatment conditions, essential improvements were desired.

Therefore, as a result of further research, the present inventor found that the zincating property and the plating property are greatly affected by the compositional conditions of the conductor material, and that it is more electrochemically effective than Al in a basic bath, and has a lower cathodic polarization property. Reduce Zn, Cu, Ni
, Contains at least two or more types of elements such as Sn, the content is 0.03 to 0, oswt%, and Al is 99.60
It has been found that a conductor material made of an aluminum alloy with a composition of wt% or more has good zincating properties and plating properties, has excellent adhesion of the plating film after plating, and does not cause the problem of blistering on the cut end surface after plating. .

That is, it is more electrochemically active than Al in a basic bath,
and elements with small cathodic polarization characteristics, especially, for example, Zn.
, Gu, Ni, Sn, etc., the barrier properties of the oxide film on the surface of the material decrease, resulting in poor zincate treatment properties (film adhesion, uniformity, and fineness). It is thought that this will improve the

In particular, this improvement in zincate processability is achieved by zn%Cu.

This is achieved by containing two or more types of Ni, Sn, etc., rather than just one type.
In particular, this is achieved by including Zn and Cu, and the sum of the contents of these two or more elements is 0.03
A remarkable effect is exhibited in the case of ~o, oswt. Similarly, if the content of these elements exceeds o, swt%, the conductivity will deteriorate.

In addition, the conductor material is as shown in JIS H4180.
Si, Fe and other unavoidable impurities, T are added to improve conductivity.
Contains grain refining agents such as i and B according to JIS 1060
In JI81060, for example, Si is 0.25wt% or less and Fe is 0.35w.
Although it is t% or less, Sl is 0.10wt% or less,
From the viewpoint of electrical conductivity, it is preferable that the Fe content be 0, zo'wt% or less, and the sum of the Si and Fe contents be 0.28wt% or less.

[Examples 1 to 11] Aluminum alloys having compositions Nos. 1 to 11 shown in Table 1 were cast, and the diameter was 278r1'Tr'11 and the length was 500r1'.
A billet of rrI was produced, and a flat bar having a width of 250 rrfT'I and a plate thickness of 10 rrm was produced by direct extrusion at a temperature of 400 to 450°C.

After cutting this flat bar into a predetermined length, 10
W't% NaOH Perform alkaline etching at 170°C for 40 seconds, and after etching, wash with water to reduce to 10 wt%.
Neutralize with HNO, room temperature for 30 seconds, and wash again with water.

Thereafter, a zincate treatment is performed using 100 g of ZnO and 500 g/C of NaOH at room temperature for 1 minute, and after the zincate treatment, it is washed with water.

After washing with water, Cu strike plating is performed in a cuprous chloride, soda cyanide, and sodium tartrate bath, and then Cu plating is performed in a copper cyanide, sodium cyanide, and Rodan salt bath.

After this Qu plating, S
Perform n plating.

[Comparative Examples 1 to 3] Aluminum alloys having compositions Nos. 12 to 14 shown in Table 1 were cast, and the same procedure as in Example 1 was conducted using the cast aluminum alloys.

[Characteristics test]

Regarding Examples 1 to 1] and Comparative Examples 1 to 3,
Table 1 shows the zincate treatment properties (removal and adhesion of the zincate film), plating properties (swelling of the end face after plating), and electrical conductivity.

Claims (1)

[Claims] ■Contains at least two or more elements that are more electrochemically responsible than Al in a basic bath and that reduce cathode polarization, the content of which is 0.03 to 0, oswt%, Al is 9
A conductor material comprising 9.6wt% or more. ■In the conductor material according to claim 1, the element that is more electrochemically responsible than Al in a basic bath and reduces cathodic polarization is Znv (:'uv selected from the group of Nl and Sn). What you can do.