High-Temperature Oxidation
High-temperature oxidation is a chemical reaction of metals with oxygen at high temperatures, without liquid electrolytes. It forms a dense scale layer that affects resistance.
Physical-Chemical Mechanism of Action
At elevated temperatures, metals react with oxygen from the air and form an oxide layer. This process is independent of liquid electrolytes and is described by the chemical equation 4Fe + 3O₂ → 2Fe₂O₃.
Metallurgical Relevance & Welding Risks
High-temperature oxidation can lead to a dense scale layer that protects the material from further oxidation. However, it can also cause distortion and loss of strength if the layer becomes too thick or does not adhere well. This can happen especially at high temperatures and long exposure times.
Workshop Practice & Instructions
To avoid high-temperature oxidation, metals should be well protected before use in high-temperature environments. This can be achieved by a thin layer of silicon or titanium oxide. During welding, it is important to control temperatures so they are not too high to avoid excessive oxidation. Additionally, metals with high oxidation resistance should be chosen.