ferrocerium vs pyrophoric alloy

ferrocerium and pyrophoric alloy both are nouns.

Word	Noun	Adjective	Verb	Adverb
ferrocerium	Yes	No	No	No
pyrophoric alloy	Yes	No	No	No

As nouns, pyrophoric alloy is a hypernym of ferrocerium; that is, pyrophoric alloy is a word with a broader meaning than ferrocerium:

ferrocerium: a pyrophoric alloy of iron with cerium; used for lighter flints
pyrophoric alloy: an alloy that emits sparks when struck or scratched with steel; used in lighter flints

ferrocerium (noun)	pyrophoric alloy (noun)
a pyrophoric alloy of iron with cerium; used for lighter flints	an alloy that emits sparks when struck or scratched with steel; used in lighter flints