How do you get armor for metal gear Zeke in Metal Gear Solid peace walker

Hi there! Any of the Cocoon battles will give you armor. Just make sure that you do not damage the armor in any way. The best way to do that is to NOT hit the AI pod, because the armor is very close to it, and will likely be hit as well.
The best way that I've found, is to first destroy the ventilation ducts underneath Cocoon. At that point there will be vents that pop out of the front near the turrets. You should then destroy those and all of the turrets on the sides - this will help you avoid damaging the armor AND will allow you to unlock all of the AI parts' memory boards inside the AI pod. If you successfully void the armor pieces, then you should get it once you finish the mission.