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Alloys of tungsten and molybdenum with iron group metals have attracted considerable attention due to their speci¯c magnetic, electrical, mechanical, thermal and corrosion resistance properties. Among them, nickel and tungsten (Ni-W) alloys are particularly interesting because they exhibit good corrosion resistance in diferent aqueous media and high hardness and ductility. Therefore, they have been studied as candidates to protect structural metals such as steels and copper. In this work a detailed characterization by X-ray absorption spectroscopy of electrodeposited Ni-W coatings prepared by pulsating electrodeposition on steel and copper substrates is presented. X-ray Difraction, Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) results are also presented. These results are discussed in terms of the good hardness and ductility that the coatings present. Diferent Ni-W coatings were prepared with diferent pulse programs in order to determine the efect of the preparation conditions on the ¯nal structures that were formed. Both XANES and EXAFS experiments at both Ni-K and W-L3 edges were studied at the XAFS2 beamline of the Laboratorio Nacional de Luz Sincrotron (LNLS),Campinas, Brazil. Experiments were performed in °uorescence mode at room temperature. The results indicate that two main phases are found in the bulk structure: a W-rich amorphous phase and Ni-rich crystalline phases. The crystalline phases consist of crystalline domains of 7-8 nm in size of Ni(W) (fcc) solid solution (12% W content). The amorphous phase exhibits a less compact Ni-W structure and a higher W content. We have found that in both phases the W is under a metalic state without evidence of signi¯cant amounts of tungsten carbide, tungstates or citrate-tungsten complexes. The good hardness and ductility of the coatings can be related to the structure consisting of a W-rich Ni-W matrix composite reinforced by the 7-8 nm crystalline domains of the Ni(W) solid solution.