I want to know because I want to evolve my Pikachu to a Raichu, but before I do I want to know if I need to switch out Pikanium Z for Electrium Z.
Nah, Pikanium Z is only usable on Pikachu:
This item can be used on Pikachu in order to turn its Volt Tackle move into the Catastropika Z-Move
Hope I helped. :) Source