Isothermal equations of state for nanometer and micrometer nickel powders

The volume and pressure for nickel powders with nanometer and micrometer grains were measured using diamond anvil cell (DAC), energy dispersive X-ray diffraction and internal pressure standard of platinum metal in 0–50GPa pressure range. These experiment data were fitted with Birch’s and Bridgman’s equation of state, respectively, to yield the isothermal bulk modulus and its first derivative. It is found that the nanometer nickel powder is more compressible than the micrometer powder.