Polycarbide
From Tardis Wiki, the free Doctor Who reference
Polycarbide is a component, likely some type of plastic, of the Dalekanium metal used in the construction of Dalek casings. Bonded polycarbide is what makes Dalekanium.
The Doctor modified some energy blasters to pierce polycarbide, and even temporarily disable the Daleks' weapons. (DW: Doomsday)