[/caption] Show A permanent magnet is a magnet because of the orientation of its domains. Domains are the small magnetic field inherent in the crystalline structure of ferromagnetic materials. Ferromagnetic materials are the only substances capable of being made into magnets they are normally iron, nickel, or alloys that are made or rare-earth metals. A magnet is created when certain condition cause separate domains in a ferromagnetic item to be all aligned in the same direction. However the method used in most cases weak magnets can only be made. This is normally by direct contact with a naturally magnetic material or by running an electric current through it. However in the case of a field produced by rubbing it against a strong magnet is too weak and will fade over time as the domains return to their original positions. The main way that permanent magnets are created is by heating a ferromagnetic material to a key high temperature. The temperature is specific to each kind of metal but it has the effect of aligning and “fixing” the domains of the magnet in a permanent position. It is conjectured that this same process inside the Earth is what creates natural permanent magnets. Permanent magnets are important for their industrial uses especially when it comes to power generation and electric motors. The induction process for turbines and generators needs permanent magnets to turn mechanical motion into energy. They are also important for electric motors in many electronics using the reverse of the induction of electric current to make mechanical energy. As you can see without the permanent magnet we would not be able to take full advantage of the capabilities of electricity in modern devices. We have written many articles about permanent magnets for Universe Today. Here’s an article about bar magnets, and here’s an article about super magnets. If you’d like more info on permanent magnets, check out these articles from Hyperphysics and Practical Physics. We’ve also recorded an entire episode of Astronomy Cast all about Magnetism. Listen here, Episode 42: Magnetism Everywhere. References: Okay, we’ve established that magnets are amazing. They’re used in everything from car engines to computers. And of course, they hold your latest straight “A” report card or artistic masterpiece to your family’s fridge. We’ve also reviewed how magnets work, what a magnetic field is, and how to tell which pole is which. But how are they made, and what are they made of, exactly? What’s IN a magnet?  The rest of the magnets we see today are created—manmade. There is a group of materials known as ferromagnetic materials. This group includes iron, cobalt, nickel, and some alloys of rare earth elements (mainly neodymium and samarium). These ferromagnetic materials can be made magnetic by exposing them to a magnetic field using electric current. Using a magnetizing fixture that directs current through the non-magnetized part, electrons in these metals are lined up, or polarized, making the material magnetic. You can learn more about the polarization process here. Some manmade magnets will maintain their magnetic properties forever*. These are referred to as permanent magnets. Some will only be magnetic when in the presence of an external magnetic field, such as from a permanent magnet. These “temporary” magnets are called soft magnets. *Permanent magnets can lose their strong magnetism when heated to a Curie Temperature. Heating a permanent magnet to its Curie Temperature causes the aligned electrons to spin out of alignment, decreasing the object’s magnetism. Once the object’s temperature is reduced, it can be re-magnetized by the same process outlined above. Check out the Curie temperatures for the substances listed below: Another type of manmade magnet is the electromagnet. Electromagnets are created when a current of electricity moves through a coil of wire. The coil is magnetic as long as it is receiving the electrical current. But pull the plug on the electricity, and you’ll pull the plug on the magnetism, too. While you’d need highly specialized machinery to create most manmade magnets, you can create your own simple electromagnet or conduct in-depth electromagnet projects at home or in school! Tags: cobalt , content of magnet , Curie temperature , electromagnets , ferromagnets , iron , lodestone , magnet materials , magnetic materials , magnetic metals , magnets , manmade magnets , natural magnets , nickel , steel Share This: What are permanent magnets answer?Solution : Permanent magnets : Those magnets which can retain their magnetic properties for a long time at room temperature are called permanent magnets. <br> Electromagnets : A ferromagnetic substance placed inside a current carrying solenoid acts as an electromagnet.
How the magnets are made?There are several processes for making magnets, but the most common method is called Powder Metallurgy. In this process, a suitable composition is pulverized into fine powder, compacted and heated to cause densification via “liquid phase sintering”. Therefore, these magnets are most often called sintered magnets.
What are permanent magnets simple definition?Definition of permanent magnet
: a magnet that retains its magnetism after removal of the magnetizing force.
How is permanent magnet made Class 10?A permanent magnet is made from steel.
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Magnetism of Class 10.. |
What are permanent magnets How are they made?
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