Dalekanium

Dalekanium is the name of two, probably different, materials, one being what the Daleks' armour is made of (many stories), the other being an unstable explosive used to penetrate Dalek casings. The term itself is probably a neologism to describe a product of the Daleks.

The Armour
The dalekanium which the Dalek armour is made of is sometimes refered to as "bonded polycarbide" (e.g. DW: Doomsday).