JP2012006071A - Zinc alloy and end face electrode material for metallized plastic film capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide zinc alloy not containing lead (Pb) or antimony (Sb) regarded to be harmful, and an end face electrode material for a metallized plastic film capacitor not containing a harmful material and capable of maintaining electric characteristics to a certain extent.SOLUTION: The alloy contains 91.0-95.0 wt.% Zn, 3.0-5.0 wt.% Al, 1.5-3.5 wt.% Cu, 0.001-0.02 wt.% Mg, and 0.0001-0.02 wt.% Si, and is used as the end face electrode raw material for the metallized plastic film capacitor.

Description

  The present invention relates to a zinc alloy and a metallized plastic film capacitor end face electrode material, and more particularly to an environmentally safe zinc alloy containing no lead or antimony and a metallized plastic film capacitor end face electrode material using the same. is there.

  Conventionally, the metallized plastic film capacitor element and its end face electrode part cannot be used with a solder having a high melting point because the constituent material is sensitive to temperature, and the solder for low temperature aluminum mainly composed of Sn / Pb / Zn alloy. Soldering is performed using As the soldering method, thermal spraying (metallicon) using an arc spraying machine or rubbing with a flaw (friction soldering) is employed. Mainly used metal alloys are Sn 37.0-39.0%, Zn3.0-5.0%, Sb0.5-1.5%, Cu0.05-0.1%, Pb55.0-59.5%. This is a solder alloy for aluminum, and the temperature range of this alloy is a solid phase temperature of 170 ° C. and a liquid phase temperature of 224 ° C. The other is a solder alloy for aluminum comprising Sn 18.5 to 21.5% by weight, Zn 2.0 to 4.0% by weight, Sb 0.5 to 1.5% by weight, Cu 0.03 to 0.1% by weight, Pb 73.0 to 79.0% by weight. This temperature range is a solid phase temperature of 173 ° C. and a liquid phase temperature of 263 ° C.

  Currently, the lead-free metal used for the end electrodes of wound and laminated metallized plastic film capacitors is mainly zinc or zinc alloy in the first layer and Sn 80 wt% / Zn20 wt% alloy in the second layer, There are three types of alloys: Sn 70 wt% / Zn 30 wt% alloy and Sn 50 wt% / Zn 50 wt% alloy, which are selected in consideration of their relatively low price and harmfulness. It does not exhibit sufficient performance as a physical property and a physical property.

  In addition, the metal used for the end face electrode of the metallized plastic film capacitor is most important in determining the performance of the capacitor, but the metal used in the second layer is also important.

  That is, the performance of the capacitor is influenced by the bonding adhesion between the second-layer metal and the first-layer metal, and the electrical characteristics are greatly affected. Further, the physical characteristics and electrical characteristics of the capacitor are determined by the compatibility of the lead wire or lead terminal spot welded or soldered to the second layer metal and the second layer metal, and the performance of the capacitor itself is affected.

  When spot welding or soldering a lead wire or a lead terminal to the second layer metal, it is necessary to stabilize the material of the second layer metal. Conventionally, Sn / Pb solder alloy was used for the second layer metal, and safety and stability were maintained. Furthermore, three types of binary alloys, Sn 80 wt% / Zn 20 wt% alloy, Sn 70 wt% / Zn 30 wt% alloy, and Sn 50 wt% / Zn 50 wt% alloy, were used as lead-free solders. The diffusion corrosion of Zn frequently generated in the base alloy may cause trouble in the welded portion with the lead wire or the lead terminal.

  Diffusion corrosion does not cause any problems during production, but aging occurs after several years, and the welded portion is peeled off, cracked, etc. due to diffusion corrosion.

Currently, the lead-free solder for aluminum described in Patent Document 1 is mainly used.

JP 2000-58370 A

  The alloy used for the end face electrode of the metallized plastic film capacitor described in Patent Document 1 has a drawback of containing harmful antimony (Sb).

  An object of the present invention is to provide a zinc alloy that does not contain harmful lead (Pb) and antimony (Sb), and an end electrode material for a metallized plastic film capacitor that does not contain harmful substances and can maintain electrical characteristics to some extent. It is what.

The present invention for solving the above problems has the following configuration.

(1) A solder alloy composed of 91.0 to 95.0% by weight of Zn, 3.0 to 5.0% by weight of Al, 1.5 to 3.5% by weight of Cu, 0.001 to 0.02% by weight of Mg, and 0.0001 to 0.02% by weight of Si.

(2) Zn 90.0-93.0 wt%, Al 3.0-5.0 wt%, Cu 1.5-3.5 wt%, Sn 1.0-6.0 wt%, Mg 0.001-0.02 wt%, Si 0.0001-0.02 wt% Solder alloy consisting of

(3) An end face electrode material for a metallized plastic film capacitor, comprising the solder alloy according to (1) or (2).

(4) A metallized plastic film capacitor comprising a metallicon as an end face electrode material of the metallized plastic film capacitor according to (3).

(5) A metallized plastic film capacitor, wherein the end face electrode material of the metallized plastic film capacitor described in (3) is rubbed against the end face with scissors.

  According to the solder alloy of the present invention, although it is an alloy that does not contain harmful substances such as lead, cadmium, and antimony, it has good electrical characteristics and physical characteristics as a solder alloy.

  According to the end face electrode material of the metallized plastic film capacitor of the present invention, the end face of the metallized plastic film capacitor is sprayed (metallicon or metal spray) and rubbed (friction soldering) with an arc spraying machine. Good workability with little erosion.

  That is, by adding appropriate amounts of effective amounts of Al, Cu, Sn, Mg, and Si to Zn, the crystal structure is refined and the potential difference due to metal bonds is reduced, so that a uniform and stable oxide film is formed. Less than conventional binary alloy oxide film. This is because when a conventional binary alloy is used for joining by heat (such as brazing, gas burnering, or in-furnace), it causes a diffusion reaction with the base material and a diffusion reaction with the atmosphere. Dendrites occur inside the part. Moreover, secular change occurs several years later, a peeling phenomenon appears on the base material and the joint surface, and cracks appear on the surface. In order to reduce such a diffusion reaction phenomenon, the crystal structure inside the alloy is refined to reduce the electrode potential difference with the metal element. That is, since the potential difference between the aluminum base material and the solder alloy of the present invention is reduced, a uniform and stable oxide film is formed on the joint surface during alloy joining.

Forms an external electrode that is stabilized in bonding with aluminum, which is the internal electrode of the metallized plastic film, and is used for spot welding of lead wires, lead terminals, etc. on the metallicon alloy layer and friction soldering layer, which are external electrodes. Capacitors with stable electrical connection and excellent electrical and physical properties can be obtained.

It is a schematic diagram which shows the structure of a capacitor | condenser. It is a schematic diagram which shows the structure of a capacitor | condenser.

  The alloy of the present invention is a solder alloy not containing Pb, Sb and Cd. As the material for the end face electrode of the metallized plastic film capacitor, for example, the end face of the metallized plastic film capacitor obtained by winding and laminating a dielectric film deposited with aluminum is rubbed with scissors (friction soldering). ), And as a linear solder and metallicon material for forming end-face electrodes by thermal spraying technology.

Embodiment (1)
It consists of an alloy of Zn 93.48% by weight, Al 4.0% by weight, Cu 2.5% by weight, Mg 0.01% by weight, and Si 0.01% by weight. In this embodiment, when used as a metallized plastic film capacitor end face electrode material, the electrical characteristics and physical characteristics of the capacitor become better. In particular, it is effective for a dielectric film made of polyethylene terephthalate, but is particularly effective for a dielectric film made of polypropylene.

Such an effect is effectively exhibited within the following range. That is, the Zn content is preferably 91.0 to 95.0% by weight. If it exceeds this range, the joint strength of the joint cannot be sufficiently obtained. The Zn content is preferably 91.5 to 94.0% by weight. In this range, the strength of the joint is further enhanced.

The Al content is preferably 3.0 to 5.0% by weight. If it exceeds this range, the joint strength of the joint cannot be sufficiently obtained. The Al content is preferably 3.2 to 4.8% by weight. In this range, the strength of the joint is further enhanced.

The Cu content is preferably 1.5 to 3.5% by weight. If it exceeds this range, the joint strength of the joint cannot be sufficiently obtained. The Cu content is preferably 1.7 to 3.3% by weight. In this range, the strength of the joint is further enhanced.

The content of Mg is preferably 0.001 to 0.02% by weight. If it exceeds this range, the joint strength of the joint cannot be sufficiently obtained. The Mg content is preferably 0.005 to 0.015% by weight. In this range, the strength of the joint is further enhanced.

The content of Si is preferably 0.0001 to 0.02% by weight. If it exceeds this range, the joint strength of the joint cannot be sufficiently obtained. The Si content is preferably 0.0005 to 0.015% by weight. In this range, the strength of the joint is further enhanced.

  This alloy is cast into a billet of a certain size and a long casting ingot, and then the billet product is extruded to a wire diameter of 5.0 to 8.0 mm by a pressing device after the lengths are aligned. It is formed on a zinc alloy material for aluminum as a material for linear rubbing (friction soldering) and thermal spraying. However, this alloy is hard, so when it is difficult to press with a press machine, the alloy cast in a long cast ingot is rolled in stages with a grooved roll mill and stretched once with a wire diameter of about 5.0 to 8.0 mm. After a few days, the linear product in the state of rounding is put into a surface heat treatment (annealing furnace), and after a surface heat treatment (annealing furnace) for 30 to 45 minutes at a certain temperature, large, medium and small sizes are stretched. It is formed into a metallized material for thermal spraying with a wire machine.

  This embodiment (1) has a solid phase temperature of 320.0 ° C. to a liquid phase temperature of 360.0 ° C., a specific gravity of 6.5, a hardness of 32.6 Hv, an elongation of 63.0%, a tensile strength of 329.0 N / mm 2, an electrical resistivity of 10.8 μΩcm, and an electrical conductivity of 31.4%. Has characteristics.

Embodiment (2)
It is made of an alloy of Zn 90.48 wt%, Al 4.0 wt%, Cu 2.5 wt%, Sn 3.0 wt%, Mg 0.01 wt%, and Si 0.01 wt%.

  In this embodiment, when used as a metallized plastic film capacitor end face electrode material, the electrical characteristics and physical characteristics of the capacitor become better. In particular, it is effective for a dielectric film made of polyethylene terephthalate, but is particularly effective for a dielectric film made of polypropylene.

  Further, the above-described effects are particularly effective when the constituent elements are within the following ranges. That is, the Zn content is preferably 90.0 to 93.0% by weight. If it exceeds this range, the joint strength of the joint cannot be sufficiently obtained. The Zn content is preferably 90.0 to 92.0% by weight. In this range, the strength of the joint is further enhanced.

The content of Al is preferably 3.0 to 5.0% by weight. If it exceeds this range, the joint strength of the joint cannot be sufficiently obtained. The Al content is preferably 3.5 to 4.5% by weight. In this range, the strength of the joint is further enhanced.

The Cu content is preferably 1.5 to 3.5% by weight. If it exceeds this range, the joint strength of the joint cannot be sufficiently obtained. The content of Al is preferably 2.0 to 3.0% by weight. In this range, the strength of the joint is further enhanced.

The Sn content is preferably 1.0 to 6.0% by weight. If it exceeds this range, the joint strength of the joint cannot be sufficiently obtained. The Sn content is preferably 1.5 to 5.5% by weight. In this range, the strength of the joint is further enhanced.

The content of Mg is preferably 0.001 to 0.02% by weight. If it exceeds this range, the joint strength of the joint cannot be sufficiently obtained. The Mg content is preferably 0.005 to 0.015% by weight. In this range, the strength of the joint is further enhanced.

The content of Si is preferably 0.0001 to 0.02% by weight. If it exceeds this range, the joint strength of the joint cannot be sufficiently obtained. The Si content is preferably 0.0005 to 0.015% by weight. In this range, the strength of the joint is further enhanced.

This alloy is cast into a billet of a certain size and a long casting ingot, and then the billet product is extruded to a wire diameter of about 5.0 to 8.0 mm by a pressing device after the lengths are aligned. It is formed on a zinc alloy material for aluminum as a material for linear rubbing (friction soldering) and thermal spraying. However, this alloy is hard, so when it is difficult to press with a press machine, the alloy cast in a long cast ingot is rolled in stages with a grooved roll mill and stretched once with a wire diameter of about 5.0 to 8.0 mm. After a few days, the linear product in the state of rounding is put into a surface heat treatment (annealing furnace), and after a surface heat treatment (annealing furnace) for 30 to 45 minutes at a certain temperature, large, medium and small sizes are stretched. It is formed into a metallized material for thermal spraying with a wire machine.

In this embodiment (2), physical properties of a solid phase temperature of 312.0 ° C. to a liquid phase temperature of 354.7 ° C., a specific gravity of 6.5, a hardness of 31.8 Hv, an elongation of 74.0%, a tensile strength of 261.0 N / mm 2, an electrical resistivity of 9.4 μΩcm, and an electrical conductivity of 29.6% Has characteristics.

 Hereinafter, an embodiment when the solder alloy of the present invention is used as a material for an end face electrode of a metallized plastic film capacitor will be described. FIG. 1 is a schematic cross-sectional view showing the structure of a capacitor.

   This embodiment has metallized plastics having vapor-deposited films 22a and 22b in which aluminum is vapor-deposited on one side of plastic films 21a and 21b, and margins (non-deposited portions) 23a and 23b (not shown) on opposite sides, respectively. Two films are stacked and wound. The end face electrode 31 is formed by a known method such as rubbing the alloy of the present invention on the end face of the main body 20 formed by winding the films 21a and 21b, or metal spraying (metallicon). When the end face electrode is constituted by the alloy of the present invention, the bonding strength of the connecting portion 30 between the end face electrode 31 and the main body 20 is sufficiently obtained. As shown in FIG. 2, the end face electrode can be composed of a first layer 31 provided directly on the end face of the main body 20 and a second layer 32 formed on the first layer 31. Thereby, it is possible to obtain an end face electrode having sufficient bonding strength and good electrical characteristics. For example, the lead wire 4 is connected to the end face electrode 32 by spot welding.

実施例１、２の合金は、接合部の光沢及び強度とも非常に良好であった。接合部の光沢の良し悪しは、はんだ付部の割れや、酸化物の残渣の程度を表し、光沢が良い場合には、接合部の耐久性が良好であること、スポット溶接等が容易であることを示している。表１に記載されている他の比較例では、接合部の強度が十分でなかった。 A solder alloy having the configuration shown in Table 1 was rubbed against the capacitor end surface with a trowel to form a capacitor end surface electrode.

The alloys of Examples 1 and 2 were very good in the gloss and strength of the joint. The glossiness of the joint represents the degree of cracking of the soldered portion and the residue of the oxide. When the gloss is good, the durability of the joint is good and spot welding is easy. It is shown that. In the other comparative examples described in Table 1, the strength of the joint was not sufficient.

The strength of the bonded portion was measured by picking and pulling the end surface electrode portions according to Comparative Examples 1 to 11 constituting the capacitor end surface with radio pliers. In Example 1, it was confirmed that no peeling occurred even when pulled 10 times or more. Comparative Examples 1 to 11 were peeled off 10 times or less or peeled 5 times or less.

1: Metalized film capacitor 20: Main body 21: Plastic film 22: Deposition film 23: Margin 30: Junction 31: End face electrode (first layer)
32: End face electrode (second layer)
4: Lead wire

Claims (5)

Solder alloy comprising Zn 91.0-95.0%, Al 3.0-5.0%, Cu 1.5-3.5%, Mg 0.001-0.02%, Si 0.0001-0.02% by weight. Zn 90.0-93.0 wt%, Al3.0-5.0 wt%, Cu1.5-3.5 wt%, Sn1.0-6.0 wt%, Mg0.001-0.02 wt%, Si0.0001-0.02 wt% Solder alloy that becomes. An end face electrode material of a metallized plastic film capacitor, comprising the solder alloy according to claim 1. A metallized plastic film capacitor comprising the metallicon of the end face electrode material of the metallized plastic film capacitor according to claim 3. 4. The metallized plastic film capacitor according to claim 3, wherein the end electrode material of the metallized plastic film capacitor is rubbed against the end surface with scissors.

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