Final answer:
Flux is used to prevent the formation of an oxide on the metal during welding or soldering, which is a vital step in protecting the metal's integrity and preventing corrosion.
Step-by-step explanation:
Flux is a chemical compound used to prevent the formation of an oxide on the metal during processes such as welding or soldering. This substance is crucial because it helps in maintaining the quality of the metal by preventing oxidation, which is a form of corrosion. When metals like iron are exposed to oxygen, they form oxides such as rust, which can weaken the metal and cause it to deteriorate.
Several methods can be used to protect against corrosion, such as using paint, grease, or plastic to prevent oxygen and water from contacting the metal, employing cathodic protection by using more reactive metals as sacrificial anodes like zinc or magnesium, or creating metal alloys with high corrosion resistance such as stainless steel. Galvanization with zinc is another example, providing a protective layer to steel that prevents oxidation.