ELECTROLESS PLATING OF NI-MO-P ALLOY

Abstract

Electroless plating of Ni-Mo-P alloy coatings is described from a solution containing sodium pyrophosphate and ammonium chloride as ligands. Application of these ligands allowed using relatively large sodium molybdate concentrations in the solution (8…16 mM), while the high electroless plating rate (up to 20 μm/h) was preserved and semibright coatings were obtained. Depending on the sodium molybdate concentration in the solution, Ni-Mo-P alloys contained 3.5…7.4 at.% of molybdenum in the metallic state. Phosphorus was included into the alloy in the form of nickel phosphide NiP. According to the XRD data. the Ni-Mo-P coatings had a nanocrystalline structure with the coherent scattering region size of 25…34 nm.