phase change vs natural process

phase change and natural process both are nouns.

Word	Noun	Adjective	Verb	Adverb
phase change	Yes	No	No	No
natural process	Yes	No	No	No

As nouns, natural process is a hypernym of phase change; that is, natural process is a word with a broader meaning than phase change:

phase change: a change from one state (solid or liquid or gas) to another without a change in chemical composition
natural process: a process existing in or produced by nature (rather than by the intent of human beings)

Other hypernyms of phase change include action, activity, natural action.

phase change (noun)	natural process (noun)
a change from one state (solid or liquid or gas) to another without a change in chemical composition	a process existing in or produced by nature (rather than by the intent of human beings)