blending vs merging

blending and merging both are nouns.

Word	Noun	Adjective	Verb	Adverb
blending	Yes	No	No	No
merging	Yes	Yes	No	No

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

Other hyponyms of blending include confluence, conflux, homogenisation, homogenization.

blending (noun)	merging (noun)
a gradation involving small or imperceptible differences between grades	a flowing together
the act of blending components together thoroughly	the act of joining together as one

blending (adjective)	merging (adjective)
	flowing together