People first encountered magnets in ancient times. Very quickly, natural magnets (pieces of magnetic iron ore) ceased to satisfy the needs of mankind. Then the first technologies for the manufacture of artificial magnets appeared. Since then, these technologies have leaped forward.
Instructions
Step 1
All materials capable of magnetization are divided into hard magnetic and soft magnetic. The difference between them is that soft magnetic materials quickly lose their magnetic properties, while hard magnetic materials retain them for a long time.
Step 2
It is enough to run an iron block several times over a strong magnet for it to magnetize itself. If you quickly open and close the iron scissors several times, they will begin to attract needles or iron filings. This effect can be used if the needle falls into a narrow gap, and there is no permanent magnet at hand to reach it.
Step 3
A permanent magnet made by magnetizing ordinary iron does not retain its properties for long. It is enough to hit it on a hard surface or heat it above 60 degrees for it to demagnetize again.
Step 4
Various additives to iron that turn it into steel can greatly change its magnetic properties. Quenchable steel is a magnetically hard material and can form the basis for a strong magnet. Hardened steel is used to make files, hacksaw blades, etc. The stainless steel from which kitchen utensils and cutlery are made cannot be hardened or magnetized.
Step 5
At home, a permanent magnet can be made from hardened steel using an inductor. The coil must be sized so that the magnet blank fits completely inside it. If you are using mains power, be sure to include a fuse to avoid short circuits.
Step 6
In addition to iron, other materials are used in the industrial production of permanent magnets, for example, alnico, an alloy of aluminum, nickel and cobalt. But most often ferrites are used - a pressed mixture of iron oxide powder with various additives. Ferrite magnets can be formed into almost any shape at the stage of creation, they are cheap to manufacture and easy to use.
Step 7
The strength of a magnet is measured by devices called magnetometers. The strongest are magnets made from a sintered mixture of iron, boron and the rare element neodymium. It can take up to 150 kilograms to separate two small magnets made of this material.
