Influences of the phosphorus content on physicochemical properties of nickel–phosphorus deposits

Dependence of physicochemical properties, including crystalline information, morphology, microhardness, paramagnetism, roughness factor and hydrogen evolution ability, for Ni–P deposits on the phosphorus content, varying from 0 to 28 at.%, were systematically examined in this work. In general, the microhardness was gradually increased with the P content but an obvious decrease was observed when the Ni–P deposit contained sulfur (S). Nickel–phosphorus deposits with the P content above 12 at.% showed an amorphous structure while the deposits containing 4–12 at.% of P exhibited a poor crystalline structure. Morphologies of these deposits were found to be a function of the P content. The ferromagnetism of Ni was gradually transformed into paramagnetism with the introduction of P into the Ni matrix. The rate of hydrogen evolution reached a maximum at the P content of 8 at.%. This deposit exhibited the maximal roughness factor (Ra) and the highest specific activity (i/Ra) of H2 evolution.