Abstract

Nanocrystalline Ni (Ninc) obtained by mechanical milling may present improved mechanical properties paired with high abrasion resistance. Different sintering processes were used to consolidate Nanocrystaline Ni: hot pressed (HP) and hot-isostatic pressed (HIP). The microstructure, mechanical properties, and tribological were evaluated to compare the processes. X-ray diffraction patterns showed that HIP-consolidated specimens had larger crystallite sizes and 37% less microstrain when compared to the HP specimens. The nanohardness of the HIP specimens was also carried out and it was 50% lower than that of HP specimens, whereas its coefficient of friction found was 25% higher. These results show the advantages of the HP process over the HIP since the high pressure. The low sintering temperature of HP inhibited the grain growth, which leads excellent mechanical and tribological properties of Ni.