corroding vs pitting

corroding and pitting both are nouns.

Word	Noun	Adjective	Verb	Adverb
corroding	Yes	No	No	No
pitting	Yes	No	No	No

As nouns, pitting is a hyponym of corroding; that is, pitting is a word with a more specific, narrower meaning than corroding:

corroding: erosion by chemical action
pitting: the formation of small pits in a surface as a consequence of corrosion

Other hyponyms of corroding include indentation, roughness, rust, rusting.

corroding (noun)	pitting (noun)
erosion by chemical action	the formation of small pits in a surface as a consequence of corrosion