Chemical nature of phosphorus in Ni–P deposits

The composition of the as-plated Ni–P deposits, obtained by reduction of nickel ions with hypophosphite, is described as a metastable two-phase system containing Ni and Ni2P, with few, if any, elementary phosphorus as a solid solution in nickel. On heating, Ni2P reacts with nickel to form Ni3P. These results contradict recently published findings claiming an initial state containing a single-phase polycrystalline nickel in which the phosphorus is substitutionally dissolved in the fcc lattice of nickel. A possible explanation is given of the reason for the occurrence of a liquidlike structure.