Oxide layer formation
Oxide layer formation is the process where a thin protective layer of oxide forms on metal surfaces. This layer protects the metal from further corrosion.
Physico-chemical mechanism
Oxide layer formation is a chemical process where oxygen reacts with free atoms on the metal crystal and creates a protective oxide skin. This can happen through air contact or chemical reactions.
Metallurgical relevance & welding risks
Oxide layers can be both good and bad. On the plus side, they protect from further corrosion, but they can also hurt joint properties and cause poor welds. Removing the oxide before welding is key to getting a clean joint.
Workshop practice & procedures
Before welding, clean off the oxide layer thoroughly. Use mechanical polishing (e.g., with a grinder), chemical cleaners, or heat treatment. For aluminum and titanium, it's especially critical to have a clean surface because the oxide forms back very quickly.