Unity's power says "Destroy 1 Equipment card. If you do put 1 golem into play."
Can this be used on an allies equipment (with their permission of course)?
Yes. Technically you don't need their permission.
Even better. LOL.
Just be careful, destroy too many of Argent Adept's instruments or Absolute Zero's modules and they might get testy with you.
AZ was going to be testy anyway. But AA might have his own reason(s) for wanting to blow up his instruments.