Ancient Greeks and Chinese found in nature a kind of natural magnetized stone, called "magnetite." This stone can magically suck up a small piece of iron, and always swing in the same direction. Early voyagers identified the direction of the magnet as the earliest compass at sea. After thousands of years of development, today's magnet has become a powerful material in our life. Through the synthesis of different materials alloy can reach the same effect with the magnetite, but also can improve the magnetic force. Artificial magnets appeared in the 18th century, but the process of making stronger magnetic materials was slow until the Alnico was made in the 1920s. Ferrite was subsequently made in the 1950s, and rare earth magnets were made in the 1970s [Rare Earth magnets including NdFeB and SmCo]. At this point, magnetic technology has been rapid development, the magnetic material also makes the components more miniaturized.

What is magnetization (orientation) direction?

Most magnetic materials can be magnetized in the same direction to saturation, a direction called "magnetization direction" (orientation). Magnets without orientation (also called isotropic magnets) are much weaker than magnets with oriented magnets (also called anisotropic magnets).

What is the standard "North Pole" industrial definition?

The "North Pole" is defined as the magnet's north pole pointing to the North Pole of Earth after its random rotation. Similarly, the south pole of the magnet is also pointing to the south pole of the earth. How to identify the magnet's north pole without marking?

Obviously the eyes alone can not tell. You can use a compass close to the magnet, the pointer pointing to the north pole of the earth points to the south pole of the magnet.

How to handle and store magnet safely?

Always be careful because the magnets stick together and can get your fingers caught. When the magnets are adsorbed to each other, the magnets themselves may be damaged due to collisions (knocking corners or cracking a crack). Keep the magnet away from objects susceptible to magnetization, such as floppy disks, credit cards, computer monitors, watches, cell phones, medical devices and more. Keep the magnet away from pacemakers.

Larger size magnets should have plastic or cardboard spacers between each piece to ensure that the magnets can be easily separated. Magnets should be stored in a dry, constant temperature environment.

How to do magnetic separation?

Only the material that can be adsorbed on the magnet can play the role of blocking the magnetic field, and the thicker the material, the better the effect of magnetic isolation. What is the strongest magnet?

At present, the highest performance magnet is a rare earth magnet, while in rare earth magnets NdFeB is the most powerful magnet. However, in the environment of 200 degrees Celsius or above, samarium-cobalt is the most powerful magnet.