All materials capable of magnetization, divided into hard magnetic and soft magnetic. The difference between them is that the soft magnetic materials rapidly lose their magnetic properties, while the hard magnetic retain them long enough.
Quite a few times to hold the iron block strong magnet that he himself had magnetized. If several times to quickly open and close the iron scissors, they will begin to pull the needle or iron filings. This effect can be used if a needle fell in the narrow gap and the permanent magnet, to get it, not at hand.
A permanent magnet is made by magnetizing an ordinary iron, retains its properties for long. Enough to strike them on a hard surface or heat above 60 degrees so it is again demagnetized.
Various additives to iron, converting it into steel, can greatly change the magnetic properties. Steel capable of hardening, is a hard magnetic material and can be the basis for a strong magnet. Made of hardened steel, make files, hacksaw blade, etc. Stainless steel, used to make kitchen utensils and Cutlery, can not be either quenched or magnetization.
At home permanent magnet can be made of hardened steel with coil inductance. The coil should be of such size that the blank for the magnet is completely fit inside it. If you use current from the power supply, avoid short circuit, be sure to include in the diagram the fuse.
In addition to iron, in the industrial manufacture of permanent magnets used and other materials, for example, Alnico — alloy of aluminum, Nickel and cobalt. But the most commonly used ferrites — compressed mixture of a powder of iron oxides with various additives. Ferrite magnets on the stage of creation can be given almost any shape, they are cheap to manufacture and convenient to use.
The strength of a magnet is measured by instruments called magnetometers. The strongest magnets are made of sintered mixture of iron, boron and the rare element neodymium. To divide two small magnet of this material, you may want a weight of 150 pounds.
If you decide to make a permanent magnet at home, strictly observe safety precautions when working with electricity. Remember that high voltage is dangerous to life, and a short-circuit may cause fire.
Advice 2 : How to make a powerful magnet
The creation of a powerful electromagnets is a difficult technical task. In industry, as indeed in everyday life magnets of great power is required. In some States, even working trains on a magnetic cushion. The machine is with electromagnetic motor soon massively and we will be under the brand name "E-mobility". But how are the magnets of great power?
It is worth noting that the magnets are divided into several classes. There are permanent magnets is, as a rule, pieces of a specific metal alloy, possessing a certain magnetism without outside influence. But there are also electromagnets. This technical devices in which a magnetic field is generated by conducting electric current through a special coil.
Of the permanent magnets to the category of powerful can be attributed only to neodymium. With a relatively small size, they are simply stunning magnetic characteristics. First, their magnetic properties, they lose only 1% for a hundred years. Second, despite its relatively small size, they have a huge magnetic force. Neodymium magnets are made artificially. To create the necessary rare earth metal neodymium. Also used iron and boron. The resulting alloy is magnetized in a magnetic field. In the end, the neodymium magnet is ready.
In industry, widely used in powerful electromagnets. Their design is much more complicated than that of permanent magnets. To create a strong electromagnet required coil consisting of windings of copper wire and iron core. Magnetic force in this case depends on the current drawn through the coil and number of turns of wire in the winding. It is worth noting that at a certain current strength the magnetization of the iron core undergoes saturation. Therefore, the most powerful industrial magnets are manufactured without him. Instead, you add an additional number of turns of wire. The most powerful industrial magnets with iron core the number of turns of wires rarely exceeds ten thousand per meter, and used the current is two amperes.
Advice 3 : How to increase the magnet
Any permanent magnet can be justmagnetit, placing it in a certain way in the external magnetMr. box. The strengthening of the electro -magnets is due to the increase in the winding current or the number of its turns.
You will need
- - a set of permanent magnets;
- - current source;
- - insulated wire.
Use a permanent magnet. Place it in an external magnetMr. field, which is stronger than the magnetfield strength of the magnet. You can create another, more powerful permanent magnetom, and possible electromagnetOhm. Continue to hold the magnet in this field for some time and its magnetnye properties will improve. For each magnetand its strengthening depends on many factors, so the performance of this method it is impossible to predict.
To strengthen the permanent magnet, combine it with the other magnetAMI, in this case the field will increase proportionally to the number of magnets. Magnets connect to each other so that like poles were oriented the same way. Because they will start, so they need to stick together.
When reaching a certain temperature a magnet- ing properties of the permanent magnetand disappear. This point is called the Curie point. But cooling the magnetand to a temperature substantially below the Curie point does not increase its power, since this transition is the phase, that is, hopping.
Electromagnet is a core of electrical steel wrapped around it with insulated wire. Increase magneting power in two ways. First – increase the current supplied to the coil. In this case, the magnettion of the induction field will increase in proportion to the increase of the current in the coil magnet. But if the current in the winding exceeds the value of short-circuit current, it will burn out, then the electromagnet fails. Therefore, to increase the current supplied to the electromagnet to be very careful. The increase in current strength is effected by increasing the EMF of the power source.
If that's not enough, strengthen the electromagnet in another way – increase the number of coil windings without increasing its length. To do this, put a second row of wires, and if need the third. The magnetic induction field will increase proportionally to the increase in the number of turns on the coil of the electromagnet.