KR0182410B1 - Sn-bi-al alloy not containing pb - Google Patents

Abstract

A solder material that does not contain heavy metal lead (Pb), the alloying component of which contains bismuth (Bi) 0.5 to 30.0 wt% (weight percentage), and 0.1 to 3.0 wt of aluminum (Al) % (% By weight), and the remainder is tin (Sn).

Compared with the conventional lead (Pb) -tin (Sn) alloy, the new alloy of the present invention is inferior to the soldering properties such as viscosity, wettability, solidification rate and post-solidification gloss in the molten state.

Description

Tin (Sn)-Bismuth (Bi)-Aluminum (Al) alloys for solders containing no lead

The present invention relates to a tin (Sn) -bismuth (Bi) -aluminum (Al) alloy for solder that does not contain lead (Pb).

In general, when soldering electrical and electronic copper and copper alloy parts, solder containing 40 to 70 wt% (wt. Percent) of lead (Pb) is still widely used, and due to the recent lead (Pb) component Pollution problems are seriously pointed out.

It is well known that lead (Pb) is a heavy metal, and once it enters the body, it accumulates and harms the human body.

In an example of a workshop where soldering is actually performed, soldering is performed by melting the solder at a high temperature of about 400 to 420 ° C., whereby lead components are scattered in the air.

Therefore, in order to remove this, the air pollution is prevented by a dust collector or the like, but in some cases it cannot be perfect, and the economic burden for operating and repairing the device is also great.

An object of the present invention for solving the above problems is to develop a new environmentally friendly soldering alloy that does not add lead (Pb) at all, as well as to existing lead (Pb) -tin (Sn) alloy-based soldering materials Compared with lead (Sn) -bismuth (solder) containing no lead (Pb) to increase the adhesive strength of the soldering parts of electronic parts by increasing the strength and conductivity, and to reduce the electrical resistivity, thereby reducing noise. It is to provide a Bi) -aluminum (Al) alloy material.

The object of the present invention as described above is 0.5 to 30.0 wt% (weight percent) bismuth (Bi) and 0.1 to 3 wt% (weight percent) aluminum (Al) in the solder (solder) for soldering copper and copper alloy And the remainder are achieved by providing a tin (Sn) -bismuth (Bi) -aluminum (Al) alloy for solder which is free of lead (Pb), which is characterized by being composed of tin (Sn).

When explaining the configuration and the operation of the embodiment of the present invention to achieve the object as described above and to perform the problem for removing the conventional defects in detail.

Tin (Sn) and bismuth (Bi), which have a low melting point and a good alloy, are the main components, and a small amount of aluminum (Al) is alloyed as an element capable of improving the strength and soldering properties of the alloy.

In particular, the soldering characteristics such as soldering temperature, soldering speed, viscosity of the soldering material in the molten state, wettability with the soldering material and gloss after soldering are compared with those of the conventional lead (Pb) -tin (Sn) alloy. There was no inferiority.

The alloy properties show that when alloying tin (Sn) with a melting point of 231 ° C. and smear (Bi) with a melting point of 271 ° C., the melting point gradually decreases, and when the alloy weight ratio is 43:57, the melting point It becomes a low melting process alloy lowered to 139 ° C.

When the bismuth (Bi) content is increased in the binary alloy of tin (Sn) and bismuth (Bi), the strength is improved but brittleness appears.

In addition to suppressing brittleness and limiting the content of bismuth (Bi) within 0.5-30.0wt% (weight percentage) in consideration of the soldering characteristics such as viscosity, wettability, solidification rate and gloss after solidification in the molten state. To this, a small amount of aluminum (Al) in the range of 0.1 to 3 wt% (weight percent) was used, and the remainder was tin (Sn).

Here, by adjusting the content of the respective alloying elements, there is a way to control the soldering properties of the brazing material.

Hereinafter is a preferred embodiment of the present invention.

EXAMPLE

Aluminum (Al) having a high melting point must be heated to a high temperature of 700 ° C. or higher when it is dissolved together as a pure metal. In such a situation, oxidation of a metal such as Bismuth (Bi) is determined.

Therefore, aluminum (Al) should be used to make the mother alloy with tin (Sn) to lower the melting point.

In this example, a 90% tin (Sn) -10% aluminum (Al) mother alloy was made and used at a melting point of 500 ° C.

That is, when tin (Sn), bismuth (Bi) and tin (Sn) -aluminum (Al) mother alloys are charged and charged together, the melting temperature in the stone is maintained in the range of 500-550 ° C and heated. Phosphorus tin (Sn) and bismuth (Bi) are first melted and alloyed, thereby approaching the process point according to their alloy ratio to form a binary alloy having a low melting point.

In addition, the molten tin (Sn) -aluminum (Al) mother alloy, which has a relatively high melting point, is also diffused and melted by the first molten alloy of tin (Sn) and bismuth (Bi) to form a low melting ternary alloy. .

The molten metal is sometimes stirred quietly to promote dissolution uniformly and quickly.

When the tin (Sn) -aluminum (Al) master alloy is almost completely melted, it is maintained at 30-60 minutes while lowering the heating temperature so that the temperature of the masonry is 350 ° C. or lower to make a homogeneous alloy.

Table 1 below shows some representative chemical components of the soldering alloy of the present invention, and Table 2 shows the proper soldering temperature and soldering result of each alloy by dipping, and satisfies practical conditions. .

The alloy of the present invention as described above compares the effects of the soldering temperature, the soldering speed, the viscosity of the soldering material in the molten state, the wettability with the soldering material and the gloss after soldering, compared with the conventional soldering material containing a large amount of lead (Pb). It has no deterioration, and there is no content of lead (Pb), which is a heavy metal, and there is no problem of heavy metal contamination, and the electronic parts are soldered by improving the strength and conductivity as compared with the conventional lead (Pb) -tin (Sn) alloy-based soldering It has the effect of reducing the noise by increasing the negative adhesive strength and reducing the electrical resistivity.

Claims (1)

In solders for brazing copper and copper alloys, 0.5 to 30.0 wt% (weight percent) bismuth (Bi), 0.1 to 3 wt% (weight percent) aluminum (Al), and the remainder tin (Sn) A tin (Sn) -bismuth (Bi) -aluminum (Al) alloy for soldering which does not contain lead (Pb).