Verterium cortenide

From Memory Alpha, the free Star Trek reference.

Verterium cortenide is a densified composite material used to construct the inner layer of Federation starship warp coils. Verterium cortenide is produced from the minerals polysilicate verterium and monocrystal cortenum.

In 2372, USS Voyager crew member Michael Jonas sabotaged the ship's magnetic constrictors at the behest of Seska, forcing the crew to vent plasma to avert a warp core breach. The plasma burned off the inner layer of the nacelles, requiring Voyager to seek a source of replacement verterium cortenide. One such source was Hemikek IV, where Kazon-Nistrim forces were laying in wait. (VOY: "Lifesigns", "Investigations")