A Visual Encyclopedia of the Periodic Table

65

that can be used to make a permanent

magnet. Large permanent magnets are

made from a tough alloy of cobalt, nickel,

and aluminium, called alnico. A radioactive

form of cobalt, called cobalt-60, is produced

in nuclear reactors. This form is widely

employed to irradiate food, a process by

which food is exposed to a tiny dose of

radiation to kill harmful germs. Cobalt can

also produce a deep shade of blue: cobalt

blue paints and dyes are formed by reacting

aluminium with cobalt oxide.

Uses

This intense

colour does not

fade easily over

time or upon

exposure to light.

This magnet

can work at

temperatures as

high as 800°C

(1,400°F).

This symbol shows that

this fruit has been treated

with radioactive cobalt-60.

This blue glass

is manufactured

using cobalt

compounds.

These blades made of

a cobalt alloy stay hard

even when very hot.

Jet engine turbine

Tough and lightweight

artificial joints can be

made from an alloy of

cobalt and chromium.

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Cobalt

blue paints

have been

in use since

3000 bce.

This part of

the joint is screwed

into the hip bone.

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Cobalt-60 is an isotope, or form, of this

element. It is created artificially in nuclear

reactors. Because of its radioactivity, it

is useful in some cancer treatments.

FORMING AN ISOTOPE

A neutron is fired at

the cobalt-59 nucleus. Added neutron

Cobalt-59 is a

stable atom with

59 neutrons.

Cobalt-60 is a

radioactive atom

with 60 neutrons.

Per manent magnet

064-065_Cobalt.indd 65 05/01/17 2:49 pm