Choosing Between Brazing and Soldering to Joining Electronic Components

In manufacturing, some of the most important processes are also the most delicate - and as such, the most damaging if they're done wrong. At AMETEK ECP, we consider this to be doubly true given the size of the parts we produce, as well as the importance they have for many of their market applications. We take care to ensure our components' integrity so each one of them will do their job when called upon.

 

Take the choice to braze or solder in the manufacturing process for our microelectronic products. On the surface, it might seem like a choice between temperature ranges, but there's a fair bit more involved in it than that:

Soldering vs. brazing: A refresher on the basics

Engineers and metallurgists likely know the differences between these methods already, but for the sake of the average individual, let's review the essential standards of soldering and brazing, according to the definitions drawn up by the American Welding Society:

  • In soldering, the filler metal used to bind two different parts together will have a liquidus - melting point - that is less than 450 degrees Celsius (or 842 degrees Fahrenheit).

  • Brazing, by contrast, uses filler metals with a liquidus of at least 450 Celsius.

 

Beyond that difference, the main thing that sets soldering and brazing apart is the strength of the bond that results from these processes. Brazing is all but guaranteed to produce a much stronger bond than soldering - as you might expect, given that some of the metals it involves are capable of withstanding thousands of degrees in Celsius or Fahrenheit. But in some cases, stronger isn't actually better

Clearing up a simple (but important) misconception

The confusion of the average person regarding the differences between soldering and brazing only grows when seeing terms like "silver solder." By the guidelines above, silver would be a brazing filler metal, because it has far greater heat resistance than any of the prominent soldering materials - a sweltering 961.8 degrees Celsius (1,763 Fahrenheit). But silver is definitely employed as a soldering material. In such cases, it's usually an alloy blend that also features copper, cadmium and zinc.

Why soldering rather than brazing?

As pointed out by EWI, sometimes it is beneficial for the bond between two work pieces to be less rigid than what brazing will produce. In instances where the parts involved need to be flexible, or are delicate - which is exactly the case with microelectronic components - a rigid attachment just isn't necessary, and might even end up being counterproductive. In addition, the brazing process can sometimes cause serious damage to the pieces being bonded, because of the incredibly high heat required. (AMETEK and many other manufacturers choose copper for its strong electrical conductivity, which leads to our metallurgists often opting to solder the pieces where this metal is involved.)

solder

Although copper, for example, can be either soldered or brazed depending on the metal's purpose, there are certain long-term effects brazing causes that some users will find problematic. According to the Copper Development Association, high-temperature brazing causes copper to anneal and become softer. Brazed copper joints will still initially be stronger on their own, but the annealing phenomenon means the overall product the connection supports won't be quite as strong as it could be. 

AMETEK materials for soldering

Along with our use of soldering to fabricate some of our most broadly applicable components, AMETEK ECP also manufactures soldering and bonding wire for all of our customers' diverse needs. Whether searching for cost-effective lead alloy-based wire or looking for the finest, strongest gold or silver, our clients know they can find it with us.


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