Paper AS-TuP7
XPS Analysis of a Complex Metal Oxide Coatings on Stainless Steel: Depth Profiling

Tuesday, October 21, 2008, 6:30 pm, Room Hall D

A low-temperature process was used for depositing complex metal oxide films onto stainless steel (SS304). Some films contained Fe, Cr, Si, and Ca, others contained Sm and Ce, and still others had Fe and Zr. The coating process consisted of dipping the SS coupons once or several times into a patented liquid followed by a thermal treatment at temperatures comparatively lower than those experienced during more conventional CVD or PVD coating processes. This liquid plus thermal treatment coating process produced surface films ranging from 50 to 500 nanometers (nm), depending on the number of dipping steps. Coated parts have been tested in a variety of environments ranging from corrosive to abrasive and have shown enhanced surface properties leading to better performance. Thermo Fisher Scientific’s K-Alpha XPS instrument was used for characterizing the through-depth composition of these films. This instrument has a micro-focused mono-chromatic Al ka x-ray source (spot size 30-400 microns), Ar ion sputter gun, and a charge compensation system utilizing both low energy electrons and low energy Ar ions. Depth profiles were obtained on these relatively thick films (500 nm) at high acquisition rates by acquiring the data at low energy resolution (i.e. high pass energy). Post-profiling data processing allowed the low resolution data to be transformed to high energy resolution using the Avantage Data Processing software (v.3.85) and special energy de-convolution routines. This method allowed rapid data acquisition along with detailed determination of through-depth chemistry via high energy resolution core level data. The post-processed data will be compared to Auger depth profiles and XPS data obtained using high energy resolution data acquisition at much slower acquisition rates. Research sponsored by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of FreedomCAR and Vehicle Technologies, as part of the High Temperature Materials Laboratory User Program, Oak Ridge National Laboratory, managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract number DE-AC05-00OR22725.