What is the primary purpose of flux in soldering?

The primary purpose of flux in soldering is to prevent oxidation. When metals are heated during the soldering process, they can develop an oxide layer on their surfaces. This oxide can inhibit the formation of a good joint by preventing the solder from effectively wetting the metal surfaces.

Flux works by chemically cleaning the surface of the metals being joined and creating a barrier that protects against further oxidation during the heating process. This ensures that the solder can flow properly and adhere to the surfaces, resulting in a strong and reliable joint.

While other functions such as improving conductivity or providing color may be relevant in certain contexts, they do not capture the fundamental role that flux plays in creating a strong solder joint. Additionally, flux does not increase the melting point of the materials involved; rather, it facilitates the soldering process by allowing the solder to flow more easily and bond with the metal surfaces.