The compressibility of nanocrystalline nickel

To determine if there is a crystallite size dependence of the bulk modulus of nickel, and to look for possible new high pressure phases, nanocrystalline nickel was studied under high pressure. X-ray diffraction data, using a synchrotron source, was collected under nonhydrostatic and quasi-hydrostatic conditions from 0 to 55 GPa. Analysis of the data from nonhydrostatically compressed nickel yields a bulk modulus, K, of 217.5±14 GPa, while the bulk modulus as determined from quasi-hydrostatic compression is, 185.4±10 GPa. For both cases, the pressure derivative of the bulk modulus, K′, was held constant at 4. No phase transitions were observed for either nonhydrostatic or quasi-hydrostatic compression over the pressure range of these experiments.