Isothermal compression of nitrogen doped zirconia/zirconium oxonitride Zr7O11N2 and equation of states

The compressibility of nitrogen doped zirconia ( β ′ zirconium oxonitride, Zr7O11N2) has been measured at room temperature up to 10 GPa in hydrostatic pressure medium, using a diamond anvil cell and X-ray powder diffraction. A least squares fit of the third order Birch–Murnaghan equation of state to the experimental V ( p ) -data resulted in a bulk modulus of B 0 = 254 GPa and its first pressure derivative of B 0 ′ = 14 ( ! ) . The obtained B 0 -value exceeds that of undoped monoclinic ZrO2 (212 GPa) and is comparable with that of the cubic (267 GPa) or the first orthorhombic high-pressure modification (oI, 243 GPa), which are discussed as potential hard materials. The exceptionally high value for B 0 ′ arises as consequence of vacancy ordering and preferred compression.