Key Difference – Corrosion vs Oxidation
Corrosion and oxidation are both similar processes that can happen under natural or forced conditions, but there is a difference between corrosion and oxidation processes. Both processes can be accelerated using external factors; corrosion rate can be increased by wet atmospheric conditions and oxidation rate can be increased using selective catalysts. Corrosion can be considered as a part of oxidation process; it is actually one of the most disastrous disadvantages of oxidation. A key difference between corrosion and oxidation is, corrosion mostly happens in metals and metallic materials, but oxidation occurs in many materials including living and non-living substances. For example; oxidation happens in the human body as well as in metals and non-metals.
What is Corrosion?
Corrosion is a natural process which degrades the useful properties of a material such as strength, structure, appearance and permeability. This mainly occurs in metals, but it can also take place in ceramics and certain polymers. Corrosion starts when metals or metallic materials are exposed to the atmosphere and aqueous environments. Some corrosion processes are controlled by itself forming a protective layer on the surface; however, in some cases it completely destroys the original material. But, several precautions available can be taken to avoid or control this problem.
Corrosion is a combination of several steps, starting from the oxidation of iron (Fe into Fe2+) and ending with the formation of a rust layer on the surface.
What is Oxidation?
Oxidation is an electrochemical reaction between Oxygen molecules and some other substances it may contact, including metals and living tissues. The definition of oxidation is a bit confusing; as it can be defined in different ways; the loss of electron(s) or Hydrogen atom(s) and gain of Oxygen atom(s) is said to be oxidation. The opposite process of oxidation is reduction.
The process of oxidation has both advantages and disadvantages. Improving metabolism, helping to weight loss, lowering risks of cancer, and enhancing the function of antioxidants are some of its advantages. Disadvantages are destructive processes such as rusting materials.
What is the difference between Corrosion and Oxidation?
Definition of Corrosion and Oxidation:
Corrosion: Corrosion is the process of deterioration or destruction of metals or metallic materials by means of chemical or electrochemical reactions, due to atmospheric and aqueous conditions.
Oxidation: The concept of oxidation can be defined in three ways.
1. In terms of electron transfer:
The loss of one or more electron(s) from a substance or an element is called oxidation.
Cu à Cu2+ + 2e
2. In terms of oxygen transfer:
The gain of one or more oxygen atom is called oxidation.
3. In terms of Hydrogen transfer:
The loss of one or more Hydrogen atom(s) is called oxidation.
CH3CH2OH à CH3CHO + H2
Corrosion and Oxidation Process:
Corrosion: The corrosion is an irreversible process which undergoes a number of simple changes
Oxidation: Oxidation is not a single process. When we consider the molecular level, it mainly involves two processes; oxidation and reduction. As one species oxidizes, the another species reduces.
Benefits of Corrosion and Oxidation:
Corrosion: The corrosion process is not directly beneficial to humans because it destroys materials.
Oxidation: Oxidation process has both benefits and drawbacks. Some important minerals are formed by oxidizing substances; Example: Al2O3 (Aluminum oxide). Food digestion, metabolism, prevention of cancers, burning of fuel are some advantages of oxidation. Rusting of materials is considered as the greatest disadvantage of this process.
Image Courtesy: “Nandu River Iron Bridge corrosion – 03” by Anna Frodesiak – Own work. (CC0) via Commons “Weathering 9039”. (CC BY-SA 3.0) via Commons
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