Cadmium comes from kadmia, "earth," discovered in 1817. It's found in nature with zinc. It is an excellent neutron-absorbing metal that can be made into rods to slow the chain fission reaction in nuclear reactors and is useful in zinc-cadmium batteries. Its sulphides are brightly colored and used to make cadmium yellow pigments.

USES:

1. Used to manufacture alloys: Cadmium can be made into many alloys as an element of alloy group, such as hard copper alloys containing cadmium of 0.5%~1.0%, with high tensile strength and wear resistance. Cadmium (98.65%) nickel (1.35%) alloy is the bearing material for aircraft engines. Cadmium is found in many low melting point alloys, up to 12.5% in wood fusible alloys.

2. Cadmium has a large thermal neutron capture cross section so alloys containing silver (80%) indium (15%) cadmium (5%) can be used as control rods in atomic reactors.

3. Cadmium compounds have been widely used in the manufacture of pigments, plastic stabilizers, phosphors, pesticides, paints, etc.

4. Used for electroplating, etc. Cadmium oxidation potential is high, so it can be used as a protective film of iron, steel and copper, widely used in electroplating anticorrosion, but because of its high toxicity, this use has a decreasing trend.

5. For rechargeable batteries: Nickel-cadmium, silver-cadmium and li-cadmium batteries have the advantages of small volume and large capacity

6. Cadmium is also used in the manufacture of electrical alloy, for example, the electrical contacts in electrical switches are mostly made of silver cadmium oxide material, which has the advantages of good conductivity, small arc burning, good fusion welding resistance and so on. It is widely used in household electrical switches, automobile relays and so on. However, because cadmium is toxic and affected by the EU "Waste Electronic and Electrical Equipment Directive" (WEEE) and "On the restriction of the use of certain hazardous substances in electronic and electrical equipment" (RoHS) two directives, the silver cadmium oxide materials in electrical switches are gradually replaced by environmental protection materials such as silver tin oxide, silver nickel materials.