Nanocrystalline bulk Ni processed by inert gas condensation of powders followed by compaction has shown impressive mechanical properties with strength values as high as 50% of the theoretical shear strength. However, the process of warm compaction required for densification often leads to grain growth, and flaws in the microstructure. In this study, thin films of nanocrystalline Ni were processed by magnetron sputtering to bypass the compaction process and achieve a microstructure with very narrow grain size distribution. This paper presents the grain size distribution and other microstructural features of nanocrystalline Ni films.

Ni films were grown on Si and NaCl substrates, using argon plasma generated with the help of a plasma d.c. magnetron source equipped with a Ni target of 99.99% purity. The target power used was 200 W and the argon pressure was maintained at around 6 millitorr during deposition. A pulsed dc negative bias of 0 or 100 V was applied on the Si substrate.