heat barrier vs thermal barrier

heat barrier and thermal barrier both are nouns.

Word	Noun	Adjective	Verb	Adverb
heat barrier	Yes	No	No	No
thermal barrier	Yes	No	No	No

As nouns, heat barrier and thermal barrier are synonyms defined as:

heat barrier and thermal barrier: a limit to high speed flight imposed by aerodynamic heating

heat barrier (noun)	thermal barrier (noun)
a limit to high speed flight imposed by aerodynamic heating	a limit to high speed flight imposed by aerodynamic heating