pyrophoric alloy: an alloy that emits sparks when struck or scratched with steel; used in lighter flints
alloy: a mixture containing two or more metallic elements or metallic and nonmetallic elements usually fused together or dissolving into each other when molten
femtochemistry: the branch of chemistry that studies elementary (often very fast) chemical reactions as they occur; the experimental methods are often based on the use of femtosecond laser pulses