Characterization and Properties of Amorphous Nanocomposites

Electrodeposition has recently been used to produce various fine-structure metals. One of the major challenges in fuel cell electrocatalysis is to replace platinum by inexpensive nonnoble metals. The nickel–tungsten alloy can be particularly attractive because of its low-cost and cease of synthesis. Due to their hardness, they can successfully substitute hard chromium coatings, which are formed in the environmentally hazardous process based on hexavalent chromium. Thus, the application of this kind of alloys as surface coatings will rather expand. In this study, we will focus on Nickel-tungsten composites that were electrodeposited on stationary working electrodes from a nickel sulfate, sodium tungstate, and di-sodium tartrate-based bath under different operating conditions. The microstructures of the deposits were studied by X-ray diffraction, the morphology by scanning electron microscope (SEM), atomic force microscope (AFM) and scanning tunneling microscope (STM), and the approximate composition by energy dispersive spectroscopy (EDS), XRF and ICP. Different Ni-W phases, either amorphous or crystalline, were associated with different plating conditions.

Keywords:

Electrodeposition , Nanocomposites , Nickel , STM/AFM