An Overview of Erosion and Corrosion
Erosion and corrosion are different mechanisms applicable to different materials, and both lead to different outcomes. The one thing which is common is that both are disadvantageous for humans as well as the environment. Erosion is a mechanism involved in change in the environment and nature, whereas corrosion affects only the metal of a material. Erosion is the sloughing of an outer surface layer of oil and moving from one place to another by the means of wind, water, gravity, etc. Corrosion is a chemical mechanism where oxidation of the metal or any material takes place, leading to the deterioration of the material.
The rust formed on iron and the tarnishing of silver observed is due to corrosion. Corrosion is a chemical process where an undesirable appearance is formed due to the interaction of metals with the outer environment. Whereas erosion is a geological process where the outer layer of the earth erodes away. Erosion could happen due to wind, water, glacial etc. In erosion, moulding and wearing of large landforms occur, including weathering of rocks. Though both words seem to have different meanings, they are equally damaging to the object they are affecting.
What is Erosion?
Erosion is a type of geological process in which the materials present in earth like soil are washed out and moved away by natural forces like water, wind etc.
Causes of Erosion
There are many natural agents which can cause erosion. This includes water, air, ice, and gravity. Water is the main cause of soil erosion. Whenever heavy rain occurs, the oil gets loosened and starts flowing with water. The same is true for ice, when the ice on the ground melts, it leads to the flowing of the topmost layer. Wind can cause erosion by displacing the outer layer of soil, especially during a hurricane. At a slope, gravity can erode the outer layer during rain when rainwater, mud, and pebbles flow downward due to gravity.
Erosion Medical Term
Erosion in the medical field is referred to as any injury which means a breakdown of the outer layer of skin. In this, a part of the epidermis is sloughed off. This could be due to infection due to bacteria or fungus.
What is Corrosion?
Corrosion is usually a result of chemical reactions on the surface of a material. Corrosion is also referred to as rust. In erosion, the eroded part is taken away by the wind or water. However, in corrosion, the outer layer is converted into another compound, giving the outer layer a different colour. Corrosion leads to the deterioration of materials.
Causes of Corrosion
The most effective way to prevent the loss of any material by corrosion is to understand the cause and source of corrosion. There are many types of corrosion based on the cause of corrosion. Corrosion is the oxidation of a metal or material by oxygen when it comes in contact with moisture, air, acid rain, etc. Some chemicals, as well as biological substances, can also cause corrosion. Extreme humidity can also cause corrosion. Electronic equipment can be vulnerable to corrosion due to exposure to various corrosive gases such as chlorine, hydrogen oxides, sulphur oxidase, etc. Even in dry places, metals are prone to corrode due to moisture droplets in the air which can condense and degrade the material.
Difference between Erosions and Corrosion
The difference between erosion and corrosion is listed below.
Key Features
Both erosion and corrosion are different phenomena and both affect different objects in the environment.
Erosion affects natural objects and can lead to the loss of fertile land. However, corrosion affects the material and is responsible for its deterioration of the material.
FAQs on Difference Between Erosion and Corrosion for JEE Main 2024
1. What is the core difference between erosion and corrosion from a JEE Chemistry perspective?
The primary difference lies in the nature of the process. Corrosion is an electrochemical or chemical process that involves the degradation of a material, typically a metal, due to its reaction with the environment (e.g., oxidation). Erosion, on the other hand, is a purely physical process where material is worn away and transported by mechanical forces like wind, water, or gravity.
2. How is rust distinct from the general concept of corrosion?
Corrosion is a broad term for the degradation of any material by chemical reaction. Rusting is a specific type of corrosion that applies exclusively to iron and its alloys. Rust is chemically identified as hydrated ferric oxide (Fe₂O₃·nH₂O), which forms when iron is exposed to oxygen and moisture.
3. In engineering applications like pipelines, what is 'erosion-corrosion' and how does it occur?
Erosion-corrosion is a synergistic degradation process where the rate of material loss is accelerated due to the combined action of corrosion and erosion. It typically occurs in pipes carrying high-velocity fluids containing solid particles or bubbles. The mechanical action of erosion strips away the protective passive film (e.g., oxide layer) from the metal surface, exposing fresh, highly reactive metal to the corrosive fluid, which then corrodes rapidly.
4. How does corrosion differ from physical degradation processes like abrasion and erosion?
These processes differ in their mechanism:
- Corrosion: A chemical or electrochemical reaction (like oxidation) that converts the surface material into a different, often less desirable, compound.
- Erosion: The removal and transport of surface material by a flowing medium, such as water or wind.
- Abrasion: A mechanical process of scraping, grinding, or wearing away of a surface by friction with another moving object or particles.
5. From an electrochemical standpoint, why does preventing erosion on a metal surface also help in preventing corrosion?
Many metals, such as aluminium and stainless steel, naturally form a very thin, non-reactive passive layer (usually a metal oxide film) on their surface. This layer acts as a barrier, isolating the underlying metal from corrosive agents and preventing further electrochemical reactions. Erosion's mechanical force can physically remove this protective passive layer, exposing the active metal beneath and significantly accelerating the rate of corrosion. Therefore, preventing erosion maintains the integrity of this protective film.
6. What are some common examples of corrosion that are important for the JEE Main 2026 syllabus?
Several key examples of corrosion are relevant for the JEE Main syllabus:
- The rusting of iron to form hydrated ferric oxide (Fe₂O₃·nH₂O).
- The tarnishing of silver, which forms a black layer of silver sulphide (Ag₂S) by reacting with atmospheric sulphur compounds.
- The formation of a green coating on copper and bronze, which is a mixture of basic copper carbonate (CuCO₃·Cu(OH)₂) and copper sulphate.
7. Can corrosion occur without a medium like water or moisture, and how does this relate to erosion?
Yes, this is known as dry corrosion or high-temperature corrosion. It occurs when a metal reacts directly with surrounding gases (like O₂, N₂, SO₂) at high temperatures, without the presence of an aqueous electrolyte. A common example is the formation of mill scale on steel during hot rolling. While erosion is a separate physical process, it can affect dry corrosion by mechanically removing the oxide scale, continuously exposing fresh metal to the hot, corrosive gases and thus increasing the degradation rate.
