Pyrophoric Metal

a metal whose finely powdered form ignites on exposure to air, Pyrophoric forms have been obtained for many metals, including Fe, Co, Ni, Cr, Mn, Ti, and V. The term “pyrophoric” is also used for alloys that produce a spark under friction or slight impact; these alloys all consist of cerium in combination with other rare-earth elements. Pyrophoric alloys are used, for example, as flints in cigarette lighters.