Some magnets can be created using any of the following ways below.
Induction
Stroking
Using electricity
Since these magnets can be made, they are usually referred to as temporary magnets. Electromagnets are magnets made using electricity and so are called temporary magnet since they only show their magnetic influence when there is electricity passing through it.
Magnets made by induction and stroking are also temporary magnets. This is because; they will lose their magnetic influence when the inducing or stroking magnets are removed. This means that magnets that always exhibit their magnetic influence and characters are known as permanent magnets.
Permanent magnets are usually made from steel while temporary magnets are made from iron. Iron nails become temporary magnets when they are attached to magnets. The nails lose their Magnetism when the magnet is taken away. Materials such as steel are able to retain their magnetism for a long time.
Induction
The material to be magnetized such as an iron nail is attached to a bar magnet for some period of time. After some time, some pins are brought close to the iron nails.
It is seen that the pins become attracted to the iron nails. The iron nails is now behaving like a magnet as a result of its attachment to the bar magnet. Conclusion: Magnet can also be made by induction.
Making a Magnet by Stroking
A nail is placed on a flat surface and is stroke repeatedly in the same direction with the North Pole of the magnet. The pole is slide along the nail from end to the other and then lifted away from the nail in a large circle. It is returned to the starting end of the nail. A pin is brought close to the nail.
It is seen that the nail attracts the pin to itself.
This shows that the nail has now been magnetized because of the stroking by the bar magnet so it now shows magnetic influence on the pin. Magnet can also be made by stroking with a bar magnet.
Using Electricity
A wire is wound around a card board tube to form what is called a solenoid. Leave the ends of the wire so that, they can be connected to a source of power such as a battery in an electrical circuit. The material to be magnetized is placed in the solenoid and the current is switched on for a short time. The needle is then taken out and some pins are brought close to it.
The pins become attracted to the needle for some time. This shows that the needle becomes magnetized so, the pins were attracted. Magnets can also be made using electricity.
Molecular theory of magnetism
A popular theory of magnetism considers the molecular alignment of the material. This is known as Weber’s theory. This theory assumes that all magnetic substances are composed of tiny molecular magnets. Any unmagnetized material has the magnetic forces of its molecular magnets neutralized by adjacent molecular magnets, thereby eliminating any magnetic effect. A magnetized material will have most of its molecular magnets lined up so that the north pole of each molecule points in one direction, and the south pole faces the opposite direction. A material with its Molecules thus aligned will then have one effective north pole, and one effective south pole. An illustration of Weber’s Theory is shown in figure above, where a steel bar is magnetized by stroking. When a steel bar is stroked several times in the same direction by a magnet, the magnetic force from the north pole of the magnet causes the molecules to align themselves.
Demagnetization
After conducting a magnetic particle inspection, it is usually necessary to demagnetize the component. Remanent magnetic fields can:
Affect machining by causing cuttings to cling to a component.
interfere with electronic equipment such as a compass.
create a condition known as “arc blow” in the welding process. Arc blow may cause the weld arc to wonder or filler Metal to be repelled from the weld.
cause abrasive particles to cling to bearing or faying surfaces and increase wear.
Removal of a field may be accomplished in several ways. This random orientation of the magnetic domains can be achieved most effectively by heating the material above its curie temperature. The curie temperature for a low carbon steel is 770oC or 1390oF. When steel is heated above its curie temperature, it will become austenitic and loses its magnetic properties. When it is cooled back down, it will go through a reverse transformation and will contain no residual Magnetic Field. The material should also be placed with it long axis in an east-west orientation to avoid any influence of the Earth’s magnetic field.
It is often inconvenient to heat a material above its curie temperature to demagnetize it, so another method that returns the material to a nearly unmagnetized state is commonly used. Subjecting the component to a reversing and decreasing magnetic field will return the dipoles to a nearly random orientation throughout the material. This can be accomplished by pulling a component out and away from a coil with AC passing through it. The same can also be accomplished using an electromagnetic yoke with AC selected. Also, many stationary magnetic particle inspection units come with a demagnetization feature that slowly reduces the AC in a coil in which the component is placed.
A field meter is often used to verify that the residual flux has been removed from a component. Industry standards usually require that the magnetic flux be reduced to less than 3 gauss after completing a magnetic particle inspection.
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Methods of Preparing Magnets
Magnets are essential components in a wide range of technologies, from electric motors and generators to loudspeakers and hard drives. They are also used in medical imaging, scientific research, and many other applications.
There are a variety of methods for preparing magnets, each with its own advantages and disadvantages. The most common methods are powder metallurgy, sintering, injection molding, and dyeing.
Powder metallurgy
Powder metallurgy is a process for manufacturing solid objects from metal powders. The powders are mixed with a binder and then pressed into a mold. The mold is then heated to a high temperature, which causes the binder to burn away and the metal powders to sinter together.
Powder metallurgy is a versatile process that can be used to manufacture a wide variety of magnets. It is also a relatively inexpensive process, which makes it ideal for mass production. However, powder metallurgy magnets are not as strong as magnets made by other methods.
Sintering
Sintering is a process for manufacturing solid objects from powdered materials. The powders are heated to a high temperature, which causes them to fuse together. Sintering is a relatively simple process, but it can be difficult to control the properties of the final product.
Sintering is often used to manufacture magnets from iron or nickel powders. The magnets produced by sintering are typically not as strong as magnets made by other methods, but they are relatively inexpensive.
Injection molding
Injection molding is a process for manufacturing objects from plastic or metal. The material is heated to a liquid state and then forced into a mold. The mold is then cooled, which causes the material to solidify.
Injection molding is a versatile process that can be used to manufacture a wide variety of objects. It is also a relatively fast process, which makes it ideal for mass production. However, injection molding magnets are not as strong as magnets made by other methods.
Dyeing
Dyeing is a process for coloring materials. The material is immersed in a dye solution, which causes the dye to bind to the material.
Dyeing is often used to color magnets. The magnets produced by dyeing are typically not as strong as magnets made by other methods, but they are relatively inexpensive.
Vacuum deposition
Vacuum deposition is a process for depositing thin films of material onto a substrate. The material is vaporized in a vacuum chamber, and then the vapor is deposited onto the substrate.
Vacuum deposition is often used to coat magnets with a protective layer. The protective layer can help to prevent the magnet from corroding or from being damaged by heat or other environmental factors.
Chemical vapor deposition
Chemical vapor deposition (CVD) is a process for depositing thin films of material onto a substrate. The material is vaporized in a chamber, and then the vapor reacts with a gas in the chamber to form a solid film on the substrate.
CVD is often used to manufacture magnets. The magnets produced by CVD are typically very strong and have excellent magnetic properties. However, CVD is a relatively expensive process.
Electroplating
Electroplating is a process for depositing a thin layer of metal onto a substrate. The substrate is placed in an electrolyte solution, and then an electric current is passed through the solution. The current causes the metal to be deposited onto the substrate.
Electroplating is often used to coat magnets with a layer of a different metal. The coating can help to improve the corrosion resistance of the magnet or to change its magnetic properties.
Magnetron sputtering
Magnetron sputtering is a process for depositing thin films of material onto a substrate. The material is vaporized by a high-energy plasma, and then the vapor is deposited onto the substrate.
Magnetron sputtering is often used to manufacture magnets. The magnets produced by magnetron sputtering are typically very strong and have excellent magnetic properties. However, magnetron sputtering is a relatively expensive process.
Sol-gel processing
Sol-gel processing is a process for manufacturing materials from a sol, which is a solution of a metal salt in a solvent. The sol is then converted into a gel, which is a solid Network of particles. The gel is then heated to a high temperature, which causes it to sinter together.
Sol-gel processing is often used to manufacture magnets. The magnets produced by sol-gel processing are typically very strong and have excellent magnetic properties. However, sol-gel processing is a relatively expensive process.
Chemical etching
Chemical etching is a process for removing material from a surface by using a chemical solution. The chemical solution dissolves the material, which causes it to be removed from the surface.
Chemical etching is often used to create patterns on magnets. The patterns
Here are some frequently asked questions and short answers about methods of preparing magnets:
What are the different methods of preparing magnets?
There are many different methods of preparing magnets, but the most common are:
Powder metallurgy: This method involves mixing powdered magnetic material with a binder and then pressing it into a mold. The resulting magnet is then sintered, which is a process of heating it to a high temperature without melting it.
Injection molding: This method is similar to powder metallurgy, but instead of using a powder, it uses a liquid magnetic material. The liquid is injected into a mold and then allowed to cool and harden.
Sintering: This method involves heating a magnetic material to a high temperature without melting it. This causes the material to form crystals, which give it its magnetic properties.
Dyeing: This method involves coating a magnetic material with a dye that makes it magnetic. The dye is usually a ferromagnetic material, such as iron oxide.
What are the advantages and disadvantages of each method?
The advantages and disadvantages of each method of preparing magnets vary depending on the specific material and application. However, some general advantages and disadvantages include:
Powder metallurgy: This method is relatively inexpensive and can be used to produce a wide variety of shapes and sizes of magnets. However, it can be time-consuming and the magnets produced may not be as strong as those produced by other methods.
Injection molding: This method is faster and more efficient than powder metallurgy, and it can be used to produce complex shapes. However, it is more expensive and the magnets produced may not be as strong.
Sintering: This method is relatively simple and inexpensive, and it can be used to produce strong magnets. However, it is not suitable for all materials and the magnets produced may not be as uniform as those produced by other methods.
Dyeing: This method is simple and inexpensive, and it can be used to produce magnets of any shape or size. However, the magnets produced are not as strong as those produced by other methods and they may not be suitable for all applications.
Which method is best for a particular application?
The best method for a particular application depends on the specific material, shape, size, and strength requirements. In general, powder metallurgy is a good choice for applications where cost is a major factor, injection molding is a good choice for applications where speed and efficiency are important, sintering is a good choice for applications where strength is important, and dyeing is a good choice for applications where flexibility is important.
What are some of the latest developments in methods of preparing magnets?
Some of the latest developments in methods of preparing magnets include:
The development of new materials: New materials are being developed that have improved magnetic properties. These materials can be used to produce stronger and more efficient magnets.
The development of new manufacturing techniques: New manufacturing techniques are being developed that can produce magnets more quickly and efficiently. These techniques can also be used to produce magnets with more complex shapes and sizes.
The development of new applications: New applications for magnets are being developed all the time. These applications require magnets with specific properties, which is driving the development of new materials and manufacturing techniques.
Which of the following is not a method of preparing magnets?
(A) Sintering
(B) Casting
(C) Electroplating
(D) All of the above
The most common method of preparing magnets is:
(A) Sintering
(B) Casting
(C) Electroplating
(D) None of the above
Sintering is a process of:
(A) Heating a material to a high temperature until it melts and then cooling it slowly
(B) Heating a material to a high temperature until it melts and then cooling it quickly
(C) Heating a material to a high temperature until it becomes a liquid and then cooling it slowly
(D) Heating a material to a high temperature until it becomes a liquid and then cooling it quickly
Casting is a process of:
(A) Pouring molten metal into a mold and then allowing it to cool and solidify
(B) Pouring molten metal into a mold and then allowing it to cool and solidify under pressure
(C) Pouring molten metal into a mold and then allowing it to cool and solidify under vacuum
(D) None of the above
Electroplating is a process of:
(A) Coating a material with a thin layer of metal by passing an electric current through a solution containing the metal ions
(B) Coating a material with a thin layer of metal by spraying the metal ions onto the material
(C) Coating a material with a thin layer of metal by dipping the material into a solution containing the metal ions
(D) None of the above
Which of the following is not a type of magnet?
(A) Permanent magnet
(B) Temporary magnet
(C) Electromagnet
(D) All of the above
A permanent magnet is a magnet that:
(A) Keeps its magnetism even when there is no external magnetic field present
(B) Loses its magnetism when there is no external magnetic field present
(C) Can be either permanent or temporary
(D) None of the above
A temporary magnet is a magnet that:
(A) Keeps its magnetism even when there is no external magnetic field present
(B) Loses its magnetism when there is no external magnetic field present
(C) Can be either permanent or temporary
(D) None of the above
An electromagnet is a magnet that:
(A) Is created by passing an electric current through a coil of wire
(B) Is created by placing a material in a magnetic field
(C) Is created by heating a material to a high temperature
(D) None of the above
Which of the following is not a property of magnets?
(A) Attraction to iron
(B) Repulsion to other magnets
(C) Ability to align with a magnetic field
(D) All of the above
The ability of a magnet to attract iron is due to the:
(A) Magnetic field of the magnet
(B) Electric field of the magnet
(C) Chemical composition of the magnet
(D) None of the above
The ability of a magnet to repel other magnets is due to the:
(A) Magnetic field of the magnet
(B) Electric field of the magnet
(C) Chemical composition of the magnet
(D) None of the above
The ability of a magnet to align with a magnetic field is due to the:
(A) Magnetic field of the magnet
(B) Electric field of the magnet
(C) Chemical composition of the magnet
(D) None of the above
Which of the following is not a use of magnets?
(A) In motors
(B) In generators
(C) In compasses
(D) All of the above
Magnets are used in motors to:
(A) Create a rotating magnetic field
(B) Create a stationary magnetic field
(C) Create an electric current
(D) None of the above
Magnets are used in generators to:
(A) Create a rotating magnetic field
(B) Create a stationary magnetic field
(C) Create an electric current
(D) None of the above
Magnets are used in compasses to:
(A) Point north
(B) Point south
(C) Point east
(D) None of the above
Which of the following is not a type of magnetic material?
(A) Iron
(B) Steel
(C) Nickel
(D) All of the above
Iron is a magnetic material because it:
(A) Contains iron atoms
(B
