Question

Catastrophic oxidation occurs in metals which exhibit:

• A. Parabolic kinetics
• B. Cubic kinetics
• C. Linear kinetics
• D. Logarithmic kinetics

Hint:

Linear oxidation indicates a non-protective oxide layer — leading to rapid, uncontrolled oxidation called catastrophic oxidation.

Answer 1

The Correct Option is C

Oxidation kinetics describes how the oxide layer on a metal grows over time. The rate at which this oxide forms depends on the nature of the oxide and the metal.
In general, oxidation follows these types of kinetics:
- Parabolic kinetics: protective oxide layer, diffusion controlled.
- Logarithmic kinetics: very slow growth, often at low temperatures.
- Linear kinetics: oxide grows at a constant rate, indicating poor protection.
Catastrophic oxidation occurs when metals form a non-protective oxide film, allowing oxygen to reach the metal continuously. This happens in linear oxidation where:
- The oxide layer is porous or non-adherent.
- Oxygen can continuously react with fresh metal.
- Oxide growth is rapid and uncontrolled — leading to severe material degradation.
Hence, linear kinetics is associated with catastrophic oxidation.