JPH01212749A - Manufacture of surface modified copper-alloy bar - Google Patents

Abstract

PURPOSE:To easily manufacture a surface modified copper-alloy bar having superior color tone by coating the surface of a copper or copper-alloy bar with zinc to carry out thermal diffusion treatment, immersing the above bar in an aqueous solution of acid of a specific concentration for a specific time to carry out pickling, and then applying cold rolling to the above. CONSTITUTION:The surface of a copper or copper-alloy bar is coated with zinc or zinc alloy, which is subjected to thermal diffusion treatment about 500 deg.C for about 30min. Then, cold rolling is applied to the resulting zinc-coated copper-alloy bar. In the method for manufacturing the above surface modified copper-alloy bar, a pickling stage in which the zinc-coated copper-alloy bar after the above thermal diffusion treatment is immersed in an aqueous solution where the concentration of acid component, such as H2SO4 and HCl, is regulated to 0.1-20% for 0.5-30sec is provided at least once. By this method, the oxides formed on the surface of a diffusion layer and causing deterioration in color tone can be removed without causing dezincing. Subsequently, cold rolling is applied to the above bar, by which the surface modified copper-alloy bar having superior color tone can be obtained.

Description

[Detailed description of the invention] [Industrial field of application] The present invention provides a surface for use in fin materials for heat exchangers, etc.
Alternatively, the present invention relates to a method for producing a Cu or Cu alloy strip modified with a Zn alloy.

(Prior art) As a conventional heat exchanger, an automobile radiator usually uses CLI between multiple brass tubes that circulate refrigerant in the vertical direction.
The structure consists of alloy corrugated fins joined by soldering and a refrigerant tank attached to both ends of the tube.However, due to changes in the driving environment of automobiles in recent years, excellent corrosion resistance has been required for the radiator fin material. , extremely high thermal conductivity and good soldering properties have become increasingly demanding.

To meet these requirements, Cu or Cu is used as the fin material.
Electroplating method, chemical plating method, vapor deposition method,
After coating with Zn or Zn alloy by hot dip method, cladding method, powder method, etc., heat diffusion treatment is performed, and then, if necessary, predetermined dimensions and performance are imparted through heat treatment such as annealing and plastic processing such as cold rolling. Cu or CLJ
A surface-modified Cu alloy strip in which a Zn or Zn alloy diffusion layer is provided on the surface of the alloy strip has been developed.

Such surface treatment improves corrosion resistance through the sacrificial anode effect of the Zn or Zn alloy coating material, and improves the corrosion resistance by improving the adhesion between the Cu base material and the Zn coating material through thermal diffusion treatment. Soldering during joining is to improve properties.

[Problem to be solved by the invention]

However, in the above manufacturing method, CU or Cu
When coating the surface of an alloy strip with Zn or Zn alloy, if oxidation of the surface of the coating layer progresses for some reason, the color tone of the surface may deteriorate significantly due to oxides whose main component is Zno after thermal diffusion treatment. . Furthermore, even if oxidation of the surface of the coating layer is suppressed during the coating process, oxides containing ZnO as the main component may be generated due to the influence of the atmosphere during heat treatment, especially the oxygen partial pressure, resulting in similar color tone deterioration. is. Such deterioration or variation in color tone has become a problem that must be solved because it causes deterioration in performance such as soldering properties and a significant decrease in commercial value.

[Means to solve the problem]

In view of this, as a result of various studies, the present invention has developed a method for manufacturing surface-modified Cu alloy strips that have excellent color tone without being affected by the surface treatment during Zn or Zn alloy coating and the atmosphere during heat treatment. be. That is, the present invention provides a method for manufacturing a surface-modified copper alloy strip by coating the surface of a copper or copper alloy strip with zinc or a zinc alloy and then subjecting it to a heat diffusion treatment, in which the concentration of the acid component after the heat diffusion treatment is 0.1. 0.0 in ~20% aqueous solution.
It is characterized by providing at least one pickling step of immersion for 5 to 30 seconds.

[For production]

Zn or Z produced by the thermal diffusion treatment process as described above
The reason why the surface of the n-alloy diffusion layer is pickled is to remove oxides formed on the surface that degrade the color tone and restore the original color tone. However, the concentration of the acid component in the pickling solution was limited to 0.11% to 20% because 0.1% non-vortex does not have the above effect, and if it exceeds 20%, there is a risk of color tone deterioration due to Zn removal. The pickling liquid used here may be one commonly used for pickling Cu and Cu alloys, such as Hz S 04 or HC, f2.
It refers to an aqueous solution containing such as acid as an acid component. In addition, the immersion time in the pickling solution was limited to 0.5 to 30 seconds because if it was less than 0.5 seconds, the pickling effect would be ineffective, and if it exceeded 30 seconds, it would cause a decrease in color tone due to Zn removal. be.

〔Example〕

Next, the present invention will be explained in detail.

A Cu strip with a thickness of 0.1 m was coated with Zn by 3 μm on each side by electroplating, and then heated at 500°C in an Ar atmosphere for 30 minutes.
A thermal diffusion treatment was applied for 1 minute. Thereafter, through the manufacturing process shown in Table 1, a layer of 0.0 mm thick with a Cu-Zn alloy layer on the surface was produced.
Three strips of 05M surface-modified Cl were prepared. Note that the conditions for pickling applied at this time are also listed in Table 1.

The color tone of the surface-modified 00 strips thus obtained was visually examined and the results are shown in Table 2.

As is clear from Table 2, according to the methods Nα1 to Nα3 of the present invention, surface-modified CLJ strips with excellent color tone can be stably produced. On the other hand, it can be seen that the comparative method Nα4, in which no pickling step was provided, and Nα5 to Nα8, in which the pickling conditions were outside the specified range of the present invention, both had poor color tones.

(Effects of the Invention) As described above, according to the present invention, a surface-modified Cu alloy strip with good color tone can be easily obtained, and in particular, when used as a fin material for a radiator, soldering properties are greatly improved, etc. This has a remarkable industrial effect.

Claims (1)

[Claims] (1) In a method of manufacturing a surface-modified copper alloy strip by coating the surface of a copper or copper alloy strip with zinc or a zinc alloy, performing a heat diffusion treatment, and then cold rolling, the method includes: 0 in an aqueous solution with an acid component concentration of 0.1 to 20%.
．． A method for manufacturing a surface-modified copper alloy strip, comprising at least one pickling step of immersion for 5 to 30 seconds.