Effect of a Mixture of Saccharin and 2-Butyne-1,4-diol on Electrodeposition of Nano-Grained Ni-Mo Alloys

Abstract

Single face centered cubic (fcc) phase nano-grained Ni-Mo alloys were fabricated by electrodeposition in aqueous citrate-ammonia electrolytes with different concentration of sodium molybdate (0.5–7 g/L) with the addition of a mixture of saccharin and 2-butyne-1,4-diol. The effect of the additives mixture on the surface morphology and roughness, composition and grain size of nano-grained Ni-Mo deposits was investigated. It is demonstrated that this additives mixture effectively reduced surface roughness by eliminating bumps and tiny holes. Additionally, the additives mixture significantly reduced the grain size, especially when the concentration of sodium molybdate is low. The minimum grain size achieved with the presence of additives mixture is 4.4 nm with a Mo content of 18.7 at.%. Energy dispersive spectroscopy results indicated that the mixture of additives has little influence on the composition of the derived nano-grained Ni-Mo alloy. Steady state partial polarization together with chronopotentiometry were employed to evaluate the modification of additives to the cathodic process. It is exhibited that electrochemical behavior with the presence of additives correlates well with their effect on composition and grain size of nano-grained Ni-Mo alloys.