Chemical machining of nanocrystalline Ni

Chemical machining of nanocrystalline Ni has been studied for the first time. Mass loss as a function of machining time in aqueous FeCl3 solutions was measured. Machining rates in nanocrystalline Ni were approximately an order of magnitude higher than conventional polycrystalline Ni for the same FeCl3 concentrations. While the system obeys first-order reaction kinetics, there were significant differences in the surface morphology depending on the FeCl3 concentration. Scanning electron microscopy of samples machined at low concentration showed deep pitting, while those machined at higher concentrations exhibited the desired uniform mass loss. Present results show that room temperature machining operations can be successfully applied to nanocrystalline Ni.