Effect of bath stabiliser on performance of electrodeposited Ni-W coatings

The paper describes the influence of the addition of a stabiliser agent on the composition of the bath and the performance of the electrodeposited nickel-tungsten (Ni-W) coatings under working conditions. The effects of the working temperature (65 degrees C) and the addition of a stabiliser on the complexes of Ni and W present in a Ni-W electrolyte were analysed. It has been qualitatively demonstrated that an increase in temperature slightly modifies the speciation curves of Ni and W complexes, and the introduction of a stabiliser does not modify the formation of the metal complex, allowing the electrolyte to be stable during long periods of time. The deposit obtained in an aged electrolyte has a high resistance to corrosion and a good resistance to wear and the hardness can be elevated to similar to 1200 HV after the application of a heat treatment.