Remind me on metal treatments:
-Stainless steel can be nitride treated, but it is counterproductive to the stainless quality being previous to treatment good rust resistant and the nitride actually hurts that quality by introducing ferrous sulfate,
-Steel can be nitride treated, and that is a very positive quality,
-Lightweight alloy/aluminum cannot be nitride treated but, also, aren't prone to rust to begin with.
Therefore, only the slide and steel guts of an alloy/steel mixed gun are nitride treated. The alloy grip is not. The wear of these two different metals is either galling or the steel literally removing material from the alloy by friction.
Will the alloy grip crack however is a question of the force of the caliber recoil, not the mix of the two metals causing the galling or material friction.