Electrochemical and x-ray studies of surface films on metals

The overall aim of the work presented in this thesis is the application of x-ray techniques to the study of surface films formed electrochemically on metals. The techniques studied were X-ray Diffraction (XRD), X-ray Energy Dispersive (XED) and Extended X-ray Absorption edge Fine Structure (EXAFS) and their application was problematic. In order to show the applicability of these techniques, several systems were studied, including zinc-phosphating of steel, oxide formation on tin electrodes, oxide formation on copper electrodes, structural changes in a Ni(OH)2 electrode during charging, and calomel formation on a mercury pool electrode. These systems were chosen because of their fundamental importance and technological applications. A comparison between the use of laboratory generated x-rays and those from a storage ring (Synchrotron Radiation) is provided. In particular, a comparison between x-ray data collected on three different detectors (linear position sensitive proportional counter detector (PSPC), curved position sensitive proportional counter detector (CPS), and scintillation counter detector (SC)), is made. The design of in-situ x-ray electrochemical cells is described; and a detailed study of the properties of some x-ray window materials (Mylar, Kevlar, Kapton, Polythene etc.) is produced. Finally, the development of a facility at the SERC Laboratory (Daresbury) via a team effort is described. this facility will provide the necessary instrumentation for in-situ studies of electrochemical, solid/liquid interfaces using synchrotron radiation. (DX86227)