Characterization of Ni-P and Fe-P by X-ray absorption spectroscopy

Due to the lack of long range order and hence the absence of grain boundaries, amorphous alloys have unusual physical properties. For example, they have excellent corrosion resistance. One of the major problems in studying the corrosion behavior of amorphous alloys in aqueous solutions is that the passive oxide layers formed are usually very thin (typically a few nanometers), and are formed under the presence of a high electric field. Generally, ex situ surface analysis methods are used for investigation which involve vacuum conditions and beams of electrons or ions in the absence of electric field and electrolyte which could significantly alter the passive layers. Raman spectroscopy on the other hand could be employed in situ, however it has certain limitations as well. XANES probes electron transmissions from core levels (the 1s level for the K edge) to unoccupied levels and is thus sensitive to the valance and coordination of the absorbing atom.