Hello friends, Today's topic is related to corrosion, in which we will know what are the methods of preventing corrosion.
But, Before knowing what are the methods of preventing corrosion firstly, we have to know what is corrosion and how many types of corrosion.
So without wasting time let's start our topic what are the methods of preventing corrosion?
What is Corrosion?
Corrosion is the decay or the destruction of metals or alloys occurring in an environment with chemical or electrochemical.This is a widespread phenomenon.
It happens everywhere that we come in contacts with, such as air, water, and every kind of environment.
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| Corroded Parts |
Types of Corrosion
There are the following types of corrosion that generally occurred in a metal:
- Uniform or general corrosion
- Pitting Corrosion
- Crevice corrosion
- Concentration Cell Corrosion
- Graphitic Corrosion
- Galvanic Corrosion
Uniform or general corrosion
In this type of corrosion, metal is uniformly destroyed.This is often occurring due to rubbing with a fast-moving fluid material.
Pitting Corrosion
In this type of corrosion, erosion is irregular on the surface of the
metal.
Crevice corrosion
These types of corrosion generally occur where bolts and nuts, lap joints are
made due to which cracks can occur.
Concentration Cell Corrosion
This occurs when the surface is in an electrolytic environment where the
concentration of the corrosive liquid or the amount of dissolved oxygen
varies. Graphitic Corrosion
It is the loss of some of the iron in cast iron due to living in salty water or acid.Graphite remains in place and the metal becomes soft and weak.
Galvanic Corrosion
It is caused by joining two metals with different electrode potentials in a corrosive electrolytic environment.The interaction of two dissimilar metals can lead to galvanic corrosion.
Only one metal will be deformed which will be less stable and will be down on the elemental chart.
For example, if the brass or copper is exposed to iron, the iron starts to decay.
Now, we will know, what are the methods of preventing corrosion?
Methods of Preventing Corrosion
There are the following commonly used methods of preventing corrosion:- Painting
- Primer
- Electroplating
- Galvanizing
- Chrome Plating
- Cladding
- Silver Plating
- Gold Plating
- Nickel Plating
- Copper Plating
- Rhodium Plating
- Zinc Plating
- Cadmium Plating
- Tin Plating
- Bluing
- Calorizing
Painting
Metal painting is done for both preservation and decoration.Before painting, the surface of the metal should be thoroughly cleaned of oxidation, mill scale, rust, grease or lubrication, dust, etc.
Which must be removed by abrasion like file, emery, grinding, etc.
The method used should not only clean the metal but also a little Etch so that there can be a good bond between the paint and the metal.
Primer
Immediately after preparing and cleaning the paint surface, it is very important to apply a suitable primer on it, so that there is no further oxidation on the metal surface.Mostly primer red lead, red oxide, or zinc chromate is used on steel.
It is recommended to use zinc chromate for copper.
For
aluminum and galvanized iron, it is recommended to use an etch primer or zinc
chromate.
Electroplating
Electroplating is the process of plating one metal over another with hydrolysis, which is intended to resist corrosion.Electroplating is also of a specific type like copper plating,
silver plating, and chromium plating.
Electroplating is used extensively in industries such as automobiles, electronics, jewelry, etc.
This process is basically the use of electrolyte cells.
It has to give a negative charge on the metal and be immersed in a solution containing metal salt (electrolyte) and which has a positively charged metal ion.
Then, due to the negative and positive
charge, the two metals attract each other.
There are many metals that can be used for plating.
Hence, the right type of electrolyte has to be selected.
There are some electrolytes - acid bases, metal salts, or molten
salts.
Galvanizing
In this process, zinc coatings are used on steel or iron to prevent corrosion.The most common method is hot-dip, in which the part is immersed in a tub of melted zinc.
Galvanizing protects the lower iron or steel in the following main ways:
1. The zinc coating, when intact, does not allow the corrosive material
to pass down to the steel or iron.
2. Zinc acts as a sacrificial anode, which will preserve the
remaining zinc from the exposed steel even if
there is a scratch on the coating.
3. For better results, applying chromates on zinc is seen as
an industrial trend.
Chrome Plating
Chrome plating is an electroplating process in which chrome acid, called hexavalent chromium, is used.Chromium plating is often used for decorative purposes, but it also promotes corrosion and friction resistance.
Cladding
Cladding is the joining of two dissimilar metals. It differs from welding or gluing.
This is done by removing two metals from the dye and pressing or rolling the sheets under high pressure.
Silver Plating
While some plating can be done without chromate, others use chromate.
Pure silver plating is also possible. The most common use of silver plating is for ornamentation of ornaments, plates, cups, and trophies.
This process results in a good polish on the plating surface.
Gold Plating
Gold is known for its high resistance to oxidation and electrical conductivity.
This process is often
used to improve the conductivity of electrical connectors such as jewelry and
electronics parts.
Nickel Plating
Nickel is a famous plating material. This is used for
good decorative and corrosion resistance.It is generally used for plating on household products such as door hinges, knives, and shower fixtures.
Copper Plating
Copper plating is also famous for
metal plating in uses that require high conductivity
at low prices.
It is famous for plating electronics components such as printed circuit boards.
Copper is one of the cheaper metals for plating due
to its high plating efficiency and low material
price.
Rhodium Plating
Rhodium is a type of platinum that resists scratches and gives a shiny appearance.
Rhodium plating is used in jewelry production, especially where
there is a need to do white gold plating.
Zinc Plating
Zinc plating is often used in the automotive industry.Zinc deposition resists oxidation and corrosion.
Vehicle boards and other metal parts like nuts and bolts,
fasteners, automotive parts are zinc plated.
Cadmium Plating
Cadmium plating improves adhesion, lubricity, and corrosion resistance.
The thickness of the cadmium plating gives adequate wear protection despite being very small.
Cadmium can be effectively coated on
almost all conductive metals.
Tin Plating
Tin plating is effective for uses that require non-toxic, high ductility, good solvability, and improved resistance to corrosion.These benefits are helpful to the
electronic industry and food processing.
Bluing
Bluing is used to provide a preservative coating on a steel part.It has an oxidizing process that provides some protection from
corrosion.
The resulting coating imparts a blue or blue-black color to the
outer surface of the metal, depending on the specified process.
To do this, the steel is heated to 315 ° C by nitrate of potash (salt-peter) and immersed in a molten solution.
The
steel is kept in solution for 1 to 15 minutes, depending on the color and depth
required.
Calorizing
In this process, aluminum powder is used to prevent corrosion.So, here I discussed what are the methods of preventing corrosion and also types of corrosion I hope you all enjoy this topic.
Thank You.
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