What is the purpose of flux in soldering?

The purpose of flux in soldering is primarily to clean surfaces and prevent oxidation. When soldering, it's essential for the metal surfaces being joined to be free from contaminants such as dirt, oxidation, and grease. If these impurities are present, they can prevent the solder from making a good bond, leading to a weak joint. Flux is designed to chemically clean the surfaces as heat is applied, promoting better adhesion of the solder by ensuring that the surfaces are as pure as possible.

Moreover, flux helps prevent the formation of oxides on the metal surfaces while soldering. Oxidation can occur rapidly at the high temperatures used in soldering, and if oxides form, they can act as barriers that inhibit the flow of the solder, further weakening the joint. By minimizing or preventing oxidation, flux helps in achieving a clean, effective, and reliable solder joint. Thus, its role in maintaining the integrity of the joint through cleanliness and protection is crucial in the soldering process.