What causes corrosion?

Answer 1

Basically, corrosion is a disintegration of a material. Corrosion is typically associated with rusting, but that is only one type of corrosion. Other types of corrosion include, erosion, cavitation, fretting, galvanic, thermo-galvanic, intergranular, pitting, and more. The main causes boil down to a few root causes, chemical reactions, friction and a lack of durability.

Rust is a chemical reaction, there are more types of reactions than from water and air. Reactions from other metals, acids, etc. cause corrosion as well. Friction can cause stress cracking, fretting, and intergranular corrosion and erosion. Two pieces of metal that rub on each other can cause fretting and lead to corrosion. Or water running over a rock for a few hundred years can turn it into a smooth pebble. Durability is key. Some substances are harder than others, and thus harder to disintegrate.

Automotive Solutions:

powder coating and plating are common methods to prevent corrosion. Electroless nickel plating is common within parts like ABS sensor rings and gears. powder coating is used on pumps and tanks. zinc plating is often used on bolts and braces.

Below is a link to a study on corrosion, its costs, causes and how to prevent it.

Answer 2

Corrosion is the rusting of outer surface of the metal. Aluminum and lead metals when exposed to high humidity, corrode pretty fast. Applying paint on metals can slow down corrosion process.
There are different types of corrosion - but the most common one is rusting which happens when Iron is exposed to Oxygen andWater.

The surface of a piece of Iron in the presence of distilled de-oxygenated water will get wet - there is no chemical reaction.

The surface of a piece of Iron in the presence of Oxygen will react to produce a layer of Iron Oxide (the passivation layer) - this is quite stable and impermeable to Oxygen stopping further corrosion.

However in the presence of both Oxygen and Water the surface of a piece of Iron will react to produce Iron Hydroxide, this is a flaky material that pushes away from the pure Iron below, allowing Oxygen and Water to penetrate further into the Iron - this causes the sample to corrode - eventually all of the Iron will convert to Iron Hydroxide and the sample will lose a lot of it's structural integrity and will collapse.

Extra Credit

Older cars tend to rust more quickly by the coast and in winter. This is due to the presence of salt (from the sea or used gritting roads).

Rusting is an electrochemical process that involves the transfer of electrons from Iron to Oxygen, in solution the Na+ and Cl- ions help to catalyse the reaction.

Answer 3

Wind over time can cause corrosion. Also if the object is in the ocean, when the waves wash over the object, bringing with it small grains of sand, can also cause corronsion.

Actually, this is Erosion, not Corrosion. Corrosion is a chemical reaction and occurs as a result of a metal returning to its natural oxidised state

Answer 4

Tooth corrosion (or tooth decay) is caused by the different sugars in foods reacting to the bacteria in our mouth, which produce Plaque and give your teeth a furry feeling. The plaque love to eat away at tooth enamel and could cause tooth decay.

Also, drinking many fizzy drinks would erode away at your teeth because they have much sugar as well. This can lead to sensitive teeth if you have been drinking a lot of fizzy drinks.

Answer 5

reaction of metal surface with oxygen(atmospheric generally)causes corrosion

Answer 6

Corrosion of iron is caused by the reaction with water in the presence of oxygen. Effect of corrosion is destruction of structures and objects.