misch metal vs pyrophoric alloy

misch metal and pyrophoric alloy both are nouns.

Word	Noun	Adjective	Verb	Adverb
misch metal	Yes	No	No	No
pyrophoric alloy	Yes	No	No	No

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

misch metal: a pyrophoric alloy made from a mixture of rare-earth metals
pyrophoric alloy: an alloy that emits sparks when struck or scratched with steel; used in lighter flints

misch metal (noun)	pyrophoric alloy (noun)
a pyrophoric alloy made from a mixture of rare-earth metals	an alloy that emits sparks when struck or scratched with steel; used in lighter flints