Brazing should be selected by considering the working condition, the operational environment and usages of basic material, and economics, in particular, the followings must be remembered.

For Silver Filler Metal, it is more economics the amount of silver is lesser, but the decrease of silver may cause the problems related to m.p. and flexibility, as well as Corrosion Resistance, electrical conductivity, and mechanical features. Therefore it must be considered the operating condition of Brazing Joint and workability. Moreover, it must be reliable that the silver content control which is the most important factor of quality and prime cost.

The lower to better. If m.p is high its operating Temperature becomes also high, which results in transformation and flaming of basic material.

It's better that the temperature difference between liquid phase and solid is lesser, and it must be decreased as the interval between basic materials becomes to be shallow.
If the temperature difference is large, it is difficult to work for the elution of partial melting.

It means the flowing property of solder in working, and this may be changed by the compatibility of basic material, Heating method, environmental temperature, and selected FLUX.

It is required to review the tensile strength, shear strength, electric conductivity, corrosion resistance and Arc resistance, and it must be determined that the selection of solder, the property of basic material, and Joint design. It's not a simple process.

For vacuum and environmental brazing, a vapor pressure is to be a critical factor. It should be used as the alloy the Sn and In instead of easily volatile elements Cd and Zn, and also considered the processing and color.