JPS61210168A - Continuous hot dipping method for tin or tin alloy - Google Patents

Abstract

PURPOSE:To suppress the oxidation of a plating metal and to obtain a tin or tin alloy plating having good quality by coating an aq. inorg. soln. contg. halogen ions at an adequate ratio on a long-sized material consisting of copper, etc. and annealing the material in an annealing furnace then passing the material through a molten bath of tin or tin alloy. CONSTITUTION:The aq. soln. contg. >=0.01g/l, more preferably about <=5g/l halogen ions is coated on the long-sized material 2 which is a wire or rod consisting of copper or copper alloy and is let off from a supply bobbin 1 by passing the material 2 through a flux vessel 9 in the process for coiling the above-mentioned material 2 with a coiler 4. The material 2 is then passed through the continuous annealing furnace 5 where the material is subjected to annealing and the activation of the surface. The material is thereafter passed through a cooling vessel 6, by which the material is cooled. The cooled material 2 is passed through a hot dipping cell 8 for tin or tin alloy and is thereby subjected to hot dipping. The continuous hot dipping of the tin or tin alloy with good quality is thus executed while the generation of the oxide of the hot dipping metal is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method of continuously hot dipping tin or a tin alloy onto a long material made of copper or a copper alloy.

[Prior art]

Copper or copper alloys, which have excellent conductivity, are mainly used for wiring conductors for electrical and electronic equipment and lead wire conductors for parts. The surface is plated with tin or tin alloy. There are two methods for plating tin or tin alloys: hot-dip plating and electroplating. Hot-dip plating is widely used because it generates less pollution and can be performed using relatively simple equipment. .

Conventionally, in order to continuously hot-dip tin or tin alloy on a long material of copper or copper alloy, as shown in FIG. The long material 2 is made to run in the longitudinal direction by winding it up with a winder 4 through ~3g, and in this process, the long material 2 is passed through a continuous annealing furnace 5 to be annealed, and then passed through a cooling tank 6.
It is then passed through a flux coating tank 7 to apply flux, and finally passed through a hot-dip plating tank 8 for hot-dip plating with tin or a tin alloy.

As the flux, a mixed aqueous solution of zinc chloride and hydrochloric acid, an organic water-soluble neutral flux, or a rosin-based organic flux is usually used.

〔problem〕

When a long material coated with flux is introduced into a hot-dip plating tank, the flux components, molten metal, and oxygen in the air react with each other until the long material is wetted by the molten metal, producing a large amount of oxides. Occur. Ordering this oxide, for example, in the case of thin plating with a plating thickness of 1 μm or less, is equivalent to the amount of metal plated on a long material, which increases the loss of molten metal and has a large impact on cost.

In order to eliminate these problems, the surface of the hot water is covered with inert gas, a vacuum is created, or the surface of the long material is reduced to remove the oil and oxides that adhere to the surface, without using flux. Methods such as hot-dip plating have been proposed in the past, but these methods not only complicate the plating equipment, but also have poor wettability with the molten metal on the surface of the long material.
It has the disadvantage of deteriorating the n-quality of plating.

Solution to Problem c] In view of the problems of the prior art as described above, the present invention is capable of suppressing the generation of metal oxides during hot-dip plating and obtaining high-quality tin or tin alloy plating. The method involves applying an inorganic aqueous solution containing 0.01 g/12 or more of halogen ions to a running long material of copper or copper alloy, and then passing the long material through a continuous annealing furnace. The method is characterized in that the long material is annealed, and then passed through a molten bath of tin or a tin alloy for hot-dip plating.

To explain this in more detail with reference to FIG. 1, the long material 2 fed out from the supply bobbin 1 is
In the process of winding the long material 2 through a to 3g with the winding machine 4, the long material 2 is passed through the flux coating tank 9 to be coated with an inorganic aqueous solution containing 0.01 g/1 or more of halogen ions, and then passed through the continuous annealing furnace 5. The material is annealed and the surface of the long material is activated, then it is passed through a cooling tank 6 to cool it if necessary, and finally it is passed through a hot-dip plating tank 8 for hot-dip plating with tin or a tin alloy. .

The elongated copper or copper alloy material 2 is usually in the form of a wire or strip.

The reason why an inorganic aqueous solution containing 0.01 g/12 or more of halogen ions such as C1%Br, I, etc., such as NH4(1!, ZnC1, HBr, etc.) is used as the flux is that when an organic flux is used, This is because the plating quality will be impaired. For example, after applying organic water-soluble flux or rosin-based organic flux,
When passed through a continuous annealing furnace, the organic matter decomposes and carbonizes in the continuous annealing furnace, causing burn-in on the surface of the long material. When a long piece of material with burn-in is placed in a hot-dip plating tank after leaving the continuous annealing furnace, the burn-in area is not plated and defects occur.

In addition, the concentration of the above halogen ions is 0.01 g/l
When the amount is less, the function as a flux is insufficient. As long as the halogen ion concentration is high, there will be no quality problem, but if it is too high, it will easily corrode the continuous annealing furnace and contaminate the working environment, so 5 g/j! below,
It is preferable to set it to 3 g/l2 or less.

The continuous annealing furnace 5 may be of any type as long as it can anneal the long material 2 to be plated. For example, a heater may be placed outside a stainless steel pipe so as to sandwich it from above and below, There are types that allow long materials to pass through.

[Effect]

When a long material coated with an inorganic aqueous solution as described above is passed through a continuous annealing furnace, the long material is annealed and, at the same time, oxides of the hot-dipped metal among the components of the inorganic aqueous solution are generated by heating the long material. The excess components are vaporized and the surface of the elongated material is activated. Therefore, plating starts as soon as the long material enters the hot-dip plating bath, and oxidation of the hot-dip plated metal is suppressed.

The inside of a continuous annealing furnace is normally sealed with nitrogen gas or steam to prevent oxidation of the long material, but in the method shown in Figure 1, water contained in the applied inorganic aqueous solution is sealed. is vaporized in the continuous annealing furnace, which performs the sealing effect, so it is also possible to omit introducing sealing gas into the continuous annealing furnace.

Furthermore, the long material exiting the continuous annealing furnace is normally cooled to prevent oxidation in the air, but in the method of the present invention, the surface of the long material is protected by the inorganic aqueous solution component remaining on the surface of the long material. Therefore, cooling can be omitted. If the temperature of the hot-dip plating bath rises too much due to the heat brought in by the long material (for example, when plating a thick wire), it is necessary to cool the bath. Although water is preferably used for cooling, an inorganic aqueous solution containing 0.01 g/11 or more of the aforementioned halogen ions can also be used instead of water. Even if an inorganic aqueous solution is used, the components that generate oxides in the hot-dip plated metal will be vaporized by the residual heat of the long material before entering the hot-dip plating tank.

〔Example〕

Example 1 A tin-plated copper wire was manufactured by applying hot-dip tin plating to a thickness of 0.5 μm on the surface of a copper wire having a diameter of 0.16 mm by the method shown in FIG. First, the copper wire is NHaBr O, 6g/j
! , the copper wire was passed through an inorganic aqueous solution consisting of the remainder water, and then passed through a 5 m long continuous annealing furnace whose temperature was controlled at 500°C at a wire speed of 200 m/min, and the temperature was further controlled at 290°C. After introducing it into a hot-dip tin plating bath, it was drawn out while being squeezed with a drawing die so that the plating thickness was 0.5 μm.

At this time, the amount of oxides generated on the hot-dip tin plating bath was measured, and the obtained tin-plated copper wire was tested according to JIS 30.
An ammonium persulfate test based on JIS K 8984 was conducted by dissolving 0.100 g of anhydrous copper sulfate of the first grade specified in JIS K 8984 in approximately 500 mJ of distilled water.
7 of grade 1 ammonia water specified in IS K 8085.
Add 5ml and further dilute with distilled water to make 11)
The quality was evaluated by comparing the

Example 2 A tin-plated copper wire was produced under the same conditions as in Example 1, except that an inorganic aqueous solution consisting of 11 g/it of HCI and the balance water was used. Regarding this, the same measurements and tests as in Example 1 were performed.

Comparative Example 1 Active agent 10-t%, surfactant 1wt%, organic solvent 5w
A tin-plated copper wire was produced under the same conditions as in Example 1, except that an organic water-soluble Franks for tin plating consisting of t% and the balance water was used. Regarding this, the same measurements and tests as in Example 1 were performed.

Comparative Example 2 A tin-plated copper wire was manufactured by the conventional method shown in FIG. Conditions such as wire diameter, wire speed, temperature, flux component, and plating thickness are the same as in Example 1. Regarding this, the same measurements and tests as in Example 1 were performed.

These results are summarized in Table 1. As is clear from Table 1, according to the method of the present invention, compared to the conventional method, the amount of oxides generated on the hot-dip tin plating bath can be significantly reduced, and a tin-plated wire with good quality can be obtained. be able to.

In Table 1, in the ammonium persulfate test, ○ indicates that the test solution is thinner than the colorimetric standard solution, and × indicates that the test solution is darker than the colorimetric standard solution.

〔Effect of the invention〕

As explained above, according to the present invention, by applying an inorganic aqueous solution containing 0.01 g/12 or more halogen ions before continuous annealing, the generation of oxides in the hot-dip plated metal can be significantly suppressed. This has the advantage of reducing loss of tin or tin alloy.

Moreover, there is an advantage that the quality of plating is also improved.

[Brief explanation of the drawing]

FIG. 1 is a conceptual diagram showing an example of the continuous hot-dip plating method for tin or tin alloy according to the present invention, and FIG. 2 is a conceptual diagram showing a conventional hot-dip plating method. 2 - Long material, 5 - Continuous annealing furnace, 6 - Cooling tank, 8 - Hot-dip plating tank, 9 - Franks (inorganic aqueous solution) coating tank.

Claims (3)

[Claims] (1) A method in which a long material made of copper or a copper alloy is run in the longitudinal direction and the surface thereof is continuously hot-dipped with tin or a tin alloy, in which halogen ions are applied to the long material at a rate of 0.
After applying an inorganic aqueous solution containing 0.01 g/l or more, the long material is passed through a continuous annealing furnace to anneal it, and then the long material is passed through a molten bath of tin or tin alloy for hot-dip plating. A continuous hot-dip plating method for tin or tin alloys. (2) The continuous hot-dip plating method according to claim 1, wherein the elongated material is a wire or a strip. (3) The continuous hot-dip plating method according to claim 1, characterized in that the long material after annealing is cooled using water or an inorganic aqueous solution containing 0.01 g/l or more of halogen ions. Something to do.