JPH0438519B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a silver brazing material used in a vacuum or an atmosphere. [Prior Art] Conventionally, silver solder, gold solder, palladium solder, platinum solder, etc. have been used for brazing metals. Among these, silver solder is widely used because it has a relatively low melting point, good workability, and is relatively inexpensive. Especially among silver wax
72Ag-Cu alloy (BAg-8) is widely used in electronic parts, etc., and Ag-Cu with increased or decreased silver content taking into account melting point or price.
alloy is used. [Problems to be solved by the invention] However, since the above Ag-Cu alloy contains 28% (Wt%, the same applies hereinafter) Cu, the temperature may rise depending on the conditions of the brazing atmosphere. There are problems with high-temperature corrosion resistance, which sometimes causes oxidative discoloration, and there are also problems such as acid from pickling treatment remaining on the surface during the plating process after brazing, resulting in surface corrosion. [Means for Solving the Problems] The present invention provides a brazing material by adding Ge, Pd and Li to Ag, and further adding one or more of Fe, Co and Ni when used as a brazing material. It also has excellent corrosion resistance in the post-treatment process, sufficient spreadability and wettability, and sufficient brazing tensile strength. First, by adding Ge to Ag, the melting point can be lowered as an Ag-Ge alloy. Ge is 0.05
If it is less than %, there is almost no substantial decrease in the melting point;
From 0.05% to 19% Ge, which gives a eutectic composition, the melting point gradually decreases as the amount of Ge added increases. Adding more than 19% of Ge raises the melting point again and makes the Ag-Ge alloy brittle, inhibiting mechanical workability. When Pd is added to this Ag-Ge alloy, Fe,
Ni, Co and their alloys, such as 42Fe-Ni,
Improves wettability and spreadability on base materials such as Kovar and stainless steel. If the amount added is less than 0.01%, the effect of the addition is negligible, and if it exceeds 10%, the melting point of the alloy increases, canceling out the effect of lowering the melting point due to the addition of Ge. Furthermore, when Li is added to Ag-Ge alloy,
Fe, Ni, Co and their alloys, e.g. 42Fe−
Improves wettability and spreadability on base materials such as Ni, Kovar, and stainless steel. If the amount added is less than 0.01%, the effect of the addition is negligible, and if it exceeds 2%, segregation will be large and it is not practical. As mentioned above, both Pd and Li improve the wettability and spreadability when Fe, Ni, Co, and their alloys are used as base materials, but their mechanisms of action are different.
In other words, Li has the effect of reducing and removing oxides on the surface of the base material and lowering the interfacial energy between the base material and the molten wax, while Pd has the effect of reducing the oxides on the surface of the base material and reducing the interfacial energy between the base material and the molten wax.
This is because, while Fe, Co, and Ni hardly form a solid solution, it completely forms a solid solution with these and has a high affinity with them. Therefore, by adding both Pd and Li at the same time, the wettability and spreadability are further improved due to their synergistic effect. Furthermore, Fe, Co,
By adding one or more types of Ni, Fe, Co, Ni and alloys thereof, such as
When brazing base materials such as 42Fe-Ni, Kovar, and stainless steel, it is possible to refine the metal structure and improve the brazing strength. Addition of less than 0.01% is equivalent to no effect, and addition of more than 3% makes it difficult for these to form a solid solution with Ag, the main component, so Ge and Pd, which form a solid solution with these, must be contained in an amount greater than the upper limit. It is inappropriate to do so. [Example] Examples of the present invention using a quaternary system of Ag-Ge-Pd-Li will be described below. (1) Ag80% Ge11.95% Pd8% Li0.05% (2) Ag86% Ge 7.9% Pd6% Li0.1% (3) Ag90% Ge8% Pd1.7% Li0.3% Melting point for samples with or above, The test results for the spreading area and tensile strength are shown in Table 1. The spreading test was carried out in a vacuum or in a hydrogen atmosphere at a temperature 40° C. higher than the liquid crystal temperature of the square brazing filler metal for 2 minutes using a square brazing filler metal with a thickness of 0.1 mm and 10 mm. In addition, brazing tensile strength measurement is performed for each base material, cross section 4
The tests were conducted using an Amsler material testing machine for a mm x 4 mm butt joint. Note that brazing was performed in vacuum or in a hydrogen atmosphere at a temperature 40° C. higher depending on the liquidus temperature of each brazing filler metal.

[Table] Next, examples of the present invention in which one or more of Fe, Co, and Ni are added to Ag-Ge-Pd-Li will be described. (4) Ag80% Ge11.45% Pd8% Li0.05% Ni0.5% (5) Ag85% Ge 8.4% Pd5% Li0.1% Fe1%Co1.5% (6) Ag94% Ge 4% Pd0.5 Table 2 shows the test results for the melting point, spreading area, and tensile strength of samples containing 0.5% Fe0.5% Ni0.5% or more. Note that these tests are the same as the test methods shown in Table 1 above.

〔Effect of the invention〕

According to the present invention explained above, Ag−Ge−Pd−
Since it is an alloy whose main component is Li, it has excellent corrosion resistance at high temperatures, sufficient spreadability and wettability, and sufficient tensile strength. This solves the problem of corrosion caused by acid remaining on the surface, resulting in a silver brazing material that can be used over a wide range of areas.

[Brief explanation of drawings]

FIG. 1 is a photomicrograph of the surface of the metal structure of the present invention, and FIG. 2 is a photomicrograph of the surface of the Ag-Ge metal structure.

Claims (1)

[Claims] 1 Ge: 0.05-19Wt%, Pd: 0.01-10Wt%, Li
A silver brazing filler metal characterized by containing 0.01 to 2 Wt% of Ag and the balance being Ag. 2 Ge 0.05-19Wt%, Pd 0.01-10Wt%, Li
0.01 to 2 Wt%, and 0.01 to 3 Wt% of one or more of Fe, Co, and Ni, and the balance being Ag.