cast iron vs pearlite

cast iron and pearlite both are nouns.

Word	Noun	Adjective	Verb	Adverb
cast iron	Yes	No	No	No
pearlite	Yes	No	No	No

cast iron (noun)	pearlite (noun)
an alloy of iron containing so much carbon that it is brittle and so cannot be wrought but must be shaped by casting	a lamellar mixture of cementite and ferrite formed during the cooling of austenite; a constituent of steel and cast iron