Brazing Alloys

Brazing Alloys

Brazing alloys are generally formed from three or more metals in order for the finished alloy to be endowed with specifically desired characteristics. For example, some potentially desirable properties are the ability to melt at very specific temperatures, melt at temperatures lower than that of the base metals, the ability to withstand harsh service conditions and to be able to wet the base metals. In addition, depending on the specific application that the brazing alloy is being used for, the alloy can be applied during the heating cycle or it can be pre-placed at the desired location. Some of the most common types of brazing alloys are copper alloys, nickel alloys, silver alloys, gold alloys and aluminum alloys. Specific applications that brazing alloys are involved in making include electric transformers, refrigeration equipment, motors, spacecrafts, jet engines, missiles, radiators, heat exchangers and transmission gears. Brazing is a heat treating process that involves the use of brazing alloys, which are melted metallic filler that are then used to bond two base pieces and create an extremely strong and often hermetic joint.

Unlike other forms of heat treatment, the brazing process does not alter the internal structure of materials in order to effect the desired change. Instead, brazing utilizes a technique that is similar to both welding and soldering in terms of creating a strong and lasting joint between two components. Although the broad categories of brazing alloys have been aforementioned, the more specific common types of brazing alloys include aluminum-silicon, copper-phosphorus, copper-zinc and gold-silver. As a brazing alloy, aluminum-silicon offers advantages in that it is has a high fluidity, low density, is easily casted and has controllable mechanical properties. Copper-phosphorus, on the other hand, is an economical choice of brazing alloy and features a high tensile strength. Copper phosphorus is also known as deoxidized copper. Another copper alloy, copper-zinc is commonly known as brass and offers the properties of high malleability, excellent acoustic properties and a relatively low melting point. Lastly, gold-silver is the most expensive option of brazing alloy and a specific type of naturally-occurring gold-silver alloy known as Electrum offers the beneficial characteristics of being an inert metal while offering high ductility.