JPS63160B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention eliminates the occurrence of cracks caused by the penetration of solder into the grain boundaries of the base material to be brazed (hereinafter referred to as "base material cracks due to solder penetration"), and has good wettability. The present invention relates to a Cu--Ag alloy brazing material that has a low atmospheric pressure and a low melting point. [Prior Art] Conventionally, for example, when brazing electron tubes and vacuum equipment, when a brazing material is exposed to a vacuum brazing atmosphere, if the amount of component evaporation is large, the parts to be brazed and the inner wall of a vacuum brazing furnace may be damaged. If the brazed part is contaminated and exposed to high temperatures in vacuum during use, it will not only reduce the degree of vacuum inside the electron tube or vacuum equipment, but also contaminate the inside of the component, so it has a low vapor pressure. Brazing filler metal is used. A typical brazing filler metal with low vapor pressure of this type has a composition consisting of Cu: 27 to 29%, Ag, and the remainder of unavoidable impurities (all percentages by weight and percentages below mean weight percent). Ag-Cu alloy brazing filler metal (JIS/BAg-8) is known. However, when this Ag-Cu alloy brazing filler metal with a low vapor pressure is used for brazing base metals of Ni-Fe alloys or Kovar-type alloys, the components of the brazing filler metal may A phenomenon appears in which wax tends to penetrate into the grain boundaries of the material, and as a result, cracks often occur in the base material during or after brazing due to penetration of the wax. Therefore, the above
When brazing base metals made of Ni-Fe alloys or Kovar-type alloys, the Ag-Cu alloy brazing filler metal is used to suppress the intrusion of constituent components of the brazing filler metal into the grain boundaries of the base metal.
Ag-Cu-Pd containing 5 to 25% Pd to prevent cracking due to penetration of wax into the base material.
Alloy filler metal is used. [Problems to be solved by the invention] However, even in this Ag-Cu-Pd alloy brazing material, the melting point increases in proportion to the Pd content, and the wettability also deteriorates. At present, it cannot be said that it is a brazing material with good brazing properties. [Means for Solving the Problems] From the above-mentioned viewpoints, the present inventors focused on the conventional Ag-Cu-Pd alloy brazing filler metal, and developed a method to lower the melting point of this brazing filler metal and improve its wettability. As a result of conducting research to improve this Ag-Cu-Pd alloy brazing filler metal,
When Si is included, there is no cracking of the base material due to solder penetration, and the melting point is lowered while maintaining a low vapor pressure, and the wettability is also significantly improved. , Ni, and
Inclusion of Co not only improves the strength of the brazing filler metal without impairing the property improvements brought about by Si, but also allows the brazing filler metal components to penetrate further into the grain boundaries of the base material. Furthermore, when B and Li are added, these components have a significant deoxidizing effect, which not only prevents the oxidation of the wax during brazing, but also prevents the dissolution of gas into the molten solder. They obtained the knowledge that it becomes significantly suppressed. This invention was made based on the above knowledge, and includes Ag: 25-65%, Pd: 0.5-25%, Si: 0.25-6.5%, one or two of Fe, Ni, and Co. Species or more: Contains 1 to 10%; Furthermore, if necessary, one or two of B and Li: 0.001 to 0.8%, Cu and unavoidable impurities: the remainder. The Ag-Cu alloy brazing filler metal has a low vapor pressure and a low melting point, exhibits good wettability during brazing, and does not cause cracks in the base metal due to solder penetration. It is. Next, the reason why the composition range of the Cu--Ag alloy brazing material of the present invention is limited as described above will be explained. (a) Ag The Ag component has the effect of lowering the melting point of the brazing filler metal and improving its wettability when coexisting with Cu and Si components, as well as improving the processability of the brazing filler metal into foil and ultrafine wire. , if its content is less than 25%, the desired effect cannot be obtained; on the other hand, 65
Even if the content exceeds 25%, no further improvement effect can be obtained due to the above-mentioned action, and in consideration of economic efficiency, the content was set at 25 to 65%. In addition, when performing cold working under severe conditions, 35% or more Ag
Containment is desirable. (b) Pd The Pd component especially includes Ni-Fe brazing parts.
type alloys and Kovar type alloys have the effect of suppressing the intrusion of brazing constituents into the base metal grain boundaries during brazing, but the content is 0.5%.
If the amount is less than the desired effect, the desired effect cannot be obtained.
On the other hand, if the content exceeds 25%, the melting point of the brazing filler metal will rise and the wettability will deteriorate, so the content was set at 0.5 to 25%. (c) Si The Si component has the effect of significantly improving the wettability and lowering the melting point without affecting the vapor pressure of the brazing filler metal, but its content is 0.25%.
If the amount is less than the desired effect, the desired effect cannot be obtained.
On the other hand, if the content exceeds 6.5%, the workability of the brazing filler metal deteriorates, so the content was set at 0.25 to 6.5%. In addition, if it is necessary to perform cold working under severe conditions, 5.
% or less of Si content is desirable. (d) Fe, Ni, and Co These ingredients improve the strength of the brazing filler metal without reducing its ductility, and they also improve the strength of the brazing filler metal without reducing its ductility. If the content is less than 1%, the desired improvement effect cannot be obtained; on the other hand, if the content is less than 1%, If the content exceeds this, the processability of the brazing filler metal will deteriorate and the melting point will also rise, so the content was set at 1 to 10%. (e) B and Li These components prevent the oxidation of the solder during soldering, forcefully reduce oxides on the surface of the soldering base material, and significantly suppress the dissolution of gas into the molten solder. Because there is an equal effect,
It is included as necessary when these effects are required, but if the content is less than 0.001%,
The desired effect cannot be ensured in the above action, and on the other hand, if the content exceeds 0.8%, the workability of the brazing filler metal deteriorates, so the content was set at 0.001 to 0.8%. [Example] Next, the Cu--Ag brazing filler metal of the present invention will be explained with reference to Examples and in comparison with conventional examples. Brazing filler metals 1 to 29 of the present invention and conventional brazing filler metals 1 to 4 having the compositions shown in Table 1 were manufactured by applying a conventional melting method and a plastic working method. Next, the brazing filler metals 1 to 1 of the present invention obtained as a result

【table】

〔Effect of the invention〕

From the results shown in Table 1, it can be seen that the brazing filler metals 1 to 1 of the present invention
No. 29 all have low vapor pressures equivalent to those of conventional brazing filler metals 1 to 4, and also exhibit superior properties equivalent to or better than conventional brazing filler metal 3, in which penetration of the solder into the grain boundaries of the base material is extremely small. and conventional brazing filler metal 1
It is clear that it has a low melting point equivalent to that of 4 and 4, and also exhibits good wettability equivalent to or better than conventional brazing filler metal 4, which has good wettability. As mentioned above, the Cu-Ag brazing material of this invention is
During brazing, the penetration of solder into the grain boundaries of the base material is extremely small, and it has good wettability, low vapor pressure, and low melting point, and also has excellent workability, so it is suitable for the material of the parts to be brazed. Moreover, brazing can be performed in good condition without being restricted by shape, and the resulting brazed part has industrially useful properties such as stable performance over a long period of time.

Claims (1)

[Claims] 1 Ag: 25 to 65%, Pd: 0.5 to 25%, Si: 0.25 to 6.5%, one or more of Fe, Ni, and Co: 1 to 10%. A low melting point Cu--Ag alloy brazing filler metal with good wettability, characterized by having a composition (by weight %) of Cu and unavoidable impurities. 2 Contains Ag: 25-65%, Pd: 0.5-25%, Si: 0.25-6.5%, one or more of Fe, Ni, and Co: 1-10%, and further contains B and one or two of Li: 0.001 to 0.8
%, with the remainder consisting of Cu and unavoidable impurities (weight % or more).