**3. Conclusions**

Solid solutions of Cr and B in Ni were obtained after 40 h of MA from the elemental powders with a minimum particle size of 95 nm and with an acicular morphology. Due to the high ductility of the mixture and the high deformation energy obtained at the maximum milling time, the nanoparticles were grouped in conglomerates of the order or microns. Different coating thickness were obtained in the Ni plating and composites coatings in function of process time, obtaining a differential in thickness between the Ni pure and Ni-composite in the order of 5.47–8.26 microns and which corresponds with the increase of thickness added by the Ni-Cr-B particles, representing a more dispersion and concentration of particles proportional with the deposition time. High hardness and better wear resistance were obtained in all the composite samples independent of the process time and the particles concentration at the surface, resulting a composite coating with low friction coefficient for lubricant applications and high hardness for wear requirements. Corrosion resistance was improved in the Ni-Cr-B composites coatings lightly with respect to the Ni coating assuming that the composite coating was conformed of a Ni matrix and that the presence and concentration of Ni-Cr-B nanoparticles were not representative to improve the corrosion resistance with respect to Ni coating. We are considering the application of a heat treatment at the composite coating to increase the corrosion resistance.
