JP2017064781A - Lead-free solder alloy - Google Patents

Abstract

Provided is a lead-free solder alloy suitable for joining glass and aluminum under the same conditions as ultrasonic soldering without using conventional flux without using lead that adversely affects the environment and the like. . A lead-free solder alloy containing effective amounts of Ag, Sb, Ge, Al, Ti, Si, Zr, Mn, B, and Co in Sn and Zn as main components, wherein the solder alloy for glass and aluminum is used. Lead-free solder alloy that satisfies the required conditions.

Description

  The present invention relates to a lead-free solder alloy, and more particularly to a lead-free solder alloy suitable for joining between different kinds of glass and aluminum.

  It has been extremely difficult to join glass and aluminum with Pb—Sn solder without any treatment other than normal cleaning. Solder that can join glass and aluminum includes Pb—Sn—Zn alloy, Pb—Sn—Zn—Bi alloy, Pb—Sn—Zn—Sb alloy, Pb—Sn—Cd alloy, Pb—Sn -Zn-Cd alloys and the like are known.

JP2012-121047

  Conventional Pb—Sn—Zn alloy, Pb—Sn—Zn—Bi alloy, Pb—Sn—Zn—Sb alloy, Pb—Sn—Cd alloy, Pb—Sn—Zn—Cd alloy, or these In addition, the solder alloy containing a trace component further contains lead, so there is a risk that lead vapor that volatilizes during the soldering work may harm the health of the worker, and the alloy containing cadmium is soldered in the same way. Cadmium vapor that volatilizes during work may harm the health of the worker. In addition, a product assembled by soldering may be contaminated with water, soil, and the like by being dissolved from the product by rainwater after disposal.

The present invention has been made to solve the above-described problems. A lead-free solder alloy for joining glass and aluminum, which can maintain the workability without changing the conventional working conditions, while reducing the content of lead and cadmium to zero. It is intended to provide.

  The lead-free solder of the present invention for solving the above problems is Sn 92.0-98.0 wt%, Zn 1.0-7.0 wt%, Sb 0.1-3.0 wt%, Ag 0.01-1.0 wt%, Ge 0.005- It is characterized by containing 0.3 wt%, Al 0.001 to 0.2 wt%, Ti 0.001 to 0.1 wt%, and Si 0.001 to 0.1 wt%.

Second, it is further characterized in that any one of Zr, Mn, B, and Co is contained in an amount of 0.001 to 0.008% by weight.
Sn is a main component of lead-free solder, and Zn is contained to give a bonding force to glass, aluminum and the like. If Zn exceeds 25%, the oxidizability of the solder itself becomes intense, and at the same time, the structure of the solder becomes less dense. As a result, poor bonding tends to occur. If it is less than 0.5%, the bonding strength with glass, aluminum or the like does not increase. Zn is preferably in the range of 2 to 6% of the above range because the bonding force to glass or the like is greater, and Zn is preferably in the range of 2 to 6% of the range because the bonding force to aluminum or the like is greater. Sb has a metal bond and a covalent bond with any metal, and has an effect of densifying the metal bond, stabilizing the metal structure, increasing the heat fatigue resistance, and improving the corrosion resistance. Ag has a dense structure and works to increase electrical properties and heat fatigue resistance. Less than 0.05% has little effect, and has a feature of forming a solid solution with Sn, Zn and Sb. This makes an alloy that is more uniform and stable. Ge has good electrical conductivity, has the same function as Ag, improves electrical characteristics, and a component used for an electronic component has a better effect. Ti reacts with Sn, Zn, and Ag, and also with a small amount of Al and Si, and the internal crystal structure of the solder alloy is made dense, and a titanium oxide film is formed on the surface, forming the same effect as the spinel effect. It is added to improve water resistance and weather resistance.

Al plays a role in suppressing the oxidizing property of Zn, and after covalent bonding with Sb, the heat fatigue resistance, water resistance, weather resistance and the like increase. In addition, it is effective even in a small amount to form a stable metal compound at the time of bonding due to various glass and aluminum properties. B originally has a deoxidizing action, and suppresses crystal precipitation, crystal crystallization, and the like of the internal structure of the alloy such as Al · Zn, and the internal crystal structure is made dense and a uniform stabilized alloy is obtained. Si also has an element of the same role, and improves the wettability at the time of joining only by containing a small amount of Si in the Sn alloy. To stabilize and further refine the internal crystal structure of the alloy, by adding Mn or Zr, the alloy internal crystal structure becomes denser and a uniform stabilized alloy can be obtained. Improve wettability.

As mentioned above, taking advantage of the characteristics of individual metal elements, there are few diffusion reaction phenomena after bonding, and the crystal structure of the bonding interface and the bonded alloy part is miniaturized, which is solved by an alloy with a stable oxide film formed. Is done.

According to the present invention, the difference between the solidus temperature and the liquidus temperature is reduced, approaching the eutectic temperature, facilitating workability, reducing damage to the glass, and having high bonding strength. A lead-free solder alloy is obtained.

Sn 93.0-96.0%, Zn 3.0-5.0%, Sb 0.5-1.5%, Ag 0.01-1.0%, Ge 0.005-0.1%, Al 0.002-0.05%, In order to achieve better characteristics in workability, surface properties and bondability, the alloy composition of 0.003 to 0.01% by weight of Ti and 0.003 to 0.01% by weight of Si is preferable. Zr 0.001 to 0.005 wt%, Mn 0.001 to 0.005 wt%, B 0.001 to 0.003 wt%, Co 0.001 to 0.005 wt% are added to contain any one of the above metal elements. Lead-free solder alloy for glass and aluminum bonding.

By this means, heat resistance fatigue resistance, water resistance, weather resistance, electrical characteristics, etc. are high, and glass and aluminum lead-free solder alloy having high bonding strength are used.

Moreover, Sn93.0-96.0 weight%, Zn3.0-5.0 weight%, Sb0.5-1.5 weight%, Ag0.01-1.0 weight%, Ge0.005-0.1 weight%, Al0.002-0.05 weight%, Zr0 is preferably characterized by comprising an alloy composition of 0.003 to 0.01% by weight of Ti and 0.003 to 0.01% by weight of Si, and preferably Zr0 for better workability, surface properties and bondability. Lead-free solder alloy for joining glass and aluminum, to which 0.001 to 0.005% by weight can be added.

With this means, heat fatigue resistance, water resistance, weather resistance, etc. are large, and high bonding strength is glass and lead-free solder alloy for aluminum bonding.

Moreover, Sn93.0-96.0 weight%, Zn3.0-5.0 weight%, Sb0.5-1.5 weight%, Ag0.01-1.0 weight%, Ge0.005-0.1 weight%, Al0.002-0.05 weight%, In order to obtain better properties in workability, surface properties and bondability, Mn0 is preferably characterized by comprising an alloy composition of Ti 0.003-0.01 wt% and Si 0.003-0.01 wt%. Lead-free solder alloy for aluminum joining, which can add 0.001 to 0.005% by weight.

Moreover, Sn93.0-96.0 weight%, Zn3.0-5.0 weight%, Sb0.5-1.5 weight%, Ag0.01-1.0 weight%, Ge0.005-0.1 weight%, Al0.002-0.05 weight%, In order to achieve better characteristics in workability, surface properties and bondability, it is preferable that the composition is composed of an alloy composition of Ti 0.003 to 0.01 wt% and Si 0.003 to 0.01 wt%. Lead-free solder alloy for joining aluminum, to which 0.001 to 0.003 wt% can be added.

Moreover, Sn93.0-96.0 weight%, Zn3.0-5.0 weight%, Sb0.5-1.5 weight%, Ag0.01-1.0 weight%, Ge0.005-0.1 weight%, Al0.002-0.05 weight%, In order to achieve better properties in workability, surface properties and bondability, it is preferable that the composition is made of an alloy composition of Ti 0.003 to 0.01% by weight and Si 0.003 to 0.01% by weight. Lead-free solder alloy for aluminum joining, which can add 0.001 to 0.005% by weight.

Hereinafter, embodiments of the lead-free solder alloy for bonding glass and aluminum according to the present invention will be described.
In producing the solder for glass and aluminum bonding according to the present invention, they are mixed so as to have the respective component ratios, and are melted in the air, in a vacuum, in an inert atmosphere, or in a reducing atmosphere to form an alloy. After that, it is shaped like a rod, line or plate.
In the solder for glass and aluminum bonding of the present invention, the bonding object is glass, aluminum, metal, ceramic, metal having an oxide film, etc., and bonding between these same objects and bonding between different objects is also possible. is there.

Embodiment (1)
Sn 92.0-98.0 wt%, Zn 1.0-7.0 wt%, Sb0.1-3.0 wt%, Ag0.01-1.0 wt%, Ge0.005-0.3 wt%, Al0.001-0.2 wt%, Ti0. It is made of an alloy of 001 to 0.1% by weight and Si 0.001 to 0.1% by weight.

Embodiment (2)
Sn 92.0-98.0 wt%, Zn 1.0-7.0 wt%, Sb0.1-3.0 wt%, Ag0.01-1.0 wt%, Ge0.005-0.3 wt%, Al0.001-0.2 wt%, Ti0. It is made of an alloy of 001 to 0.1% by weight, Si 0.001 to 0.1% by weight, and Zr 0.001 to 0.005% by weight.

Embodiment (3)
Sn 92.0-98.0 wt%, Zn 1.0-7.0 wt%, Sb0.1-3.0 wt%, Ag0.01-1.0 wt%, Ge0.005-0.3 wt%, Al0.001-0.2 wt%, Ti0. It is made of an alloy of 001 to 0.1% by weight, Si 0.001 to 0.1% by weight, and Mn 0.001 to 0.005% by weight.

Embodiment (4)
Sn 92.0-98.0 wt%, Zn 1.0-7.0 wt%, Sb0.1-3.0 wt%, Ag0.01-1.0 wt%, Ge0.005-0.3 wt%, Al0.001-0.2 wt%, Ti0. It is made of an alloy of 001 to 0.1% by weight, Si 0.001 to 0.1% by weight, and B 0.001 to 0.003% by weight.

Embodiment (5)
Sn 92.0-98.0 wt%, Zn 1.0-7.0 wt%, Sb0.1-3.0 wt%, Ag0.01-1.0 wt%, Ge0.005-0.3 wt%, Al0.001-0.2 wt%, Ti0. It is made of an alloy of 001 to 0.1% by weight, Si 0.001 to 0.1% by weight, and Co 0.001 to 0.005% by weight.

In this embodiment (1), (2), (3), (4), (5), samples of the alloy compositions shown in Table 1 (Examples 1 to 5) were prepared, and the physical properties Was measured. Embodiments (1), (2), (3), (4), and (5) are suitable for use in the temperature range (200 ° C. to 215 ° C.), particularly for the portions that require high temperatures in the joints. Effective for glass, aluminum and the like.
As shown in Table 1, the lead wires are bonded to the glass with the solder alloys of Comparative Examples 1 to 7 and Examples 1 to 5, and then the lead wires are pulled to increase the bonding strength between the lead wires and the glass. The experiment was conducted. In each of the solder alloys of the examples, the connection part made of the solder alloy was not peeled off, and the lead wire itself was cut without being able to withstand the tensile force, and showed stronger joint strength than the solder alloy of the comparative example. In the solder alloys of Comparative Examples 1 to 7, the solder joints were peeled off at the tensile strength shown in Table 1. Such a result was exhibited not only for glass but also for aluminum.

  The solder alloy of the present invention has Sn 93.0-96.0 wt%, Zn 3.0-5.0 wt%, Sb 0.5-1.5 wt%, Ag 0.03-0.5 wt%, Ge 0.005-0.1 wt%, Al 0 Effective in the range of 0.002 to 0.05 wt%, Ti 0.003 to 0.01 wt%, and Si 0.003 to 0.01 wt%. Further, those containing Zr, Mn, B, Co depending on the kind of glass, the kind of aluminum, and the kind of different metal exhibit effectiveness.

  Example 1 has physical properties such as a solid phase temperature of 200.0 ° C. to a liquid phase temperature of 215.0 ° C., a specific gravity of 7.26, a hardness of 10.8 Hv, an elongation of 38.7%, a tensile strength of 30.3 MPa, an electrical resistivity of 13.0 μΩcm, and an electrical conductivity of 13.3%. .

  Example 2 has physical properties such as a solid phase temperature of 200.0 ° C. to a liquid phase temperature of 215.0 ° C., a specific gravity of 7.26, a hardness of 10.9 Hv, an elongation of 39.2%, a tensile strength of 31.1 MPa, an electrical resistivity of 12.9 μΩcm, and an electrical conductivity of 13.4%.

  Example 3 has physical properties of a solid phase temperature of 200.0 ° C. to a liquid phase temperature of 215.0 ° C., a specific gravity of 7.26, a hardness of 11.1 Hv, an elongation of 38.4, a tensile strength of 30.7 MPa, an electrical resistivity of 13.4 μΩcm, and an electrical conductivity of 13.1%.

  Example 4 has physical properties such as a solid phase temperature of 200.0 ° C. to a liquid phase temperature of 215.0 ° C., a specific gravity of 7.26, a hardness of 11.0 Hv, an elongation of 38.2%, a tensile strength of 30.1 MPa, an electrical resistivity of 13.7 μΩcm, and an electrical conductivity of 13.0%.

  Example 5 has physical properties of a solid phase temperature of 200.0 ° C. to a liquid phase temperature of 215.0 ° C., a specific gravity of 7.26, a hardness of 10.8 Hv, an elongation of 39.1%, a tensile strength of 31.0 MPa, an electrical specific resistance of 12.8 μΩcm, and an electrical conductivity of 13.3%.

The solder alloy of Comparative Example 8 has an alloy composition of Sn 95.2 wt%, Zn 3.5 wt%, Sb 1.25 wt%, Al 0.05 wt%, solid phase temperature 200.2 ° C. to liquid phase temperature 217.1 ° C. It has physical properties such as hardness 11.2 Hv, elongation 37.8%, electrical resistivity 13.8 μΩcm, conductivity 13.1%. An aluminum plate having a thickness of 2.0 mm and an aluminum plate having a thickness of 2.0 mm, a width of 10 mm, and a length of 50 mm are bonded with the solder alloys of Comparative Example 8 and Examples 1 to 5, and the two bonded aluminum plates The tensile strength test which pulls apart was done. The results are shown in Table 2. The numerical value shown in Table 2 is the load (N) applied when the aluminum plate joined with the solder alloy and the aluminum plate broke at the solder joint by the tensile strength test. Compared to Comparative Example 8, in Examples 1 to 5, when a larger tensile load was applied, the joint portion was broken.
In addition, the solder alloy of this invention has a temperature difference with a solid phase temperature and a liquid phase temperature small compared with the solder alloy of Comparative Examples 1-8, and has the performance preferable as a solder alloy.

Claims (2)

Sn 92.0-98.0 wt%, Zn 1.0-7.0 wt%, Sb0.1-3.0 wt%, Ag0.01-1.0 wt%, Ge0.005-0.3 wt%, Al0.001-0.2 wt%, Ti0. Lead-free solder alloy containing 001 to 0.1 wt% and Si 0.001 to 0.1 wt%. The lead-free solder alloy according to claim 1, further comprising 0.001 to 0.008% by weight of any one of Zr, Mn, B, and Co.