rusting vs erosion

rusting and erosion both are nouns.

Word	Noun	Adjective	Verb	Adverb
rusting	Yes	No	No	No
erosion	Yes	No	No	No

As nouns, erosion is a hypernym of rusting; that is, erosion is a word with a broader meaning than rusting:

rusting: the formation of reddish-brown ferric oxides on iron by low-temperature oxidation in the presence of water
erosion: erosion by chemical action

Other hypernyms of rusting include corroding, corrosion, oxidation, oxidisation, oxidization.

rusting (noun)	erosion (noun)
the formation of reddish-brown ferric oxides on iron by low-temperature oxidation in the presence of water	(geology) the mechanical process of wearing or grinding something down (as by particles washing over it), also figuratively
	erosion by chemical action
	a gradual decline of something
	condition in which the earth's surface is worn away by the action of water and wind