Novel synthesis of metastable HCP nickel by water quenching

It is shown for the first time that water quenching from 1100 °C could yield the metastable HCP Ni phase. The lattice parameters of HCP Ni obtained by water quenching are surprisingly smaller than those reported for either Ni ₃C, NiCl₂ or Ni synthesized by chemical routes. Our current findings may partially clarify discrepancies around stability of HCP Ni. In addition, NiO was not formed when quenching from 1100 °C but only when quenching from 950 °C. It is therefore logical to assume that the metastable Ni HCP phase is less prone to oxygen attack as compared to the expanded FCC phase.