Abstract : The faradaic and non-faradaic reactivity of lithium in the thionyl chloride battery system has been studied using AES, XPS, and SEM/EDAX. The passivating film has been characterized as lithium chloride and found to contain substantial quantities of aluminum and sulfur. XPS results show definitely that in battery discharged lithium sulfur occluded within the passive film is present in multiple oxidation states, including sulfide. The reactivity of the lithium metal surface with O2, CO2, CO, and N2 was studied. The 'black spots' were synthesized and analyzed as a lithium oxynitride. A model for ion transport across the passivating lithium chloride film was postulated and its implications discussed. The current interrupt method was tested on a model system. An A/D interface and associated software was developed to enable rapid, accurate data acquisition.
AES and XPS measurements of silicon nitride films with refractive indices ranging from 1.93 to 2.08 have been made. The films studied were grown on silicon (100) substrates by CVD using varying mixtures of silane and ammonia. Earlier AES studies of similar silicon nitride films have suggested that these films are microscopic mixtures of Si and Si3N4. We present XPS data which show that there is no measurable ’’free’’ silicon (i.e. the level of ’’free’’ silicon is ≲3 at. %) in the silicon nitride films with refractive indices ≲2.02. AES data show an increase in oxygen content corresponding to a decrease in refractive index of the silicon nitride films. These AES measurements agree qualitatively with measurements of the physical properties of silicon oxynitride films.
With the recent advances in surface analytical instrumentation, a methodology now exists which enables optical thin films to be studied in considerable detail. Scanning Auger spectroscopy with argon ion etching capabilities in conjunction with scanning electron microscopy, backscatter electron microscopy, optical microscopy, and light element energy dispersive x-ray spectroscopy have been successfully used at the University of Dayton to study coating defects and radiation induced damage in a variety of specimens. A brief description of the capabilities and limitations of some of these techniques will be given. Ball cratering, a relatively obscure technique by which underlying layers in an optical stack can be exposed, has proven to be a power- ful tool which has extended the range of the above mentioned analytical techniques. Some examples of adhesion failures, crack phenomena, substrate and film failures, and Auger depth profiling will be presented.
The Faradaic and non-Faradaic reactivity of lithium in the thionyl chloride battery system has been studied using AES, XPS, and SEM/EDAX. The passivating film has been characterized as lithium chloride and found to contain substantial quantities of aluminum and sulfur. XPS results show definitely that in battery discharged lithium sulfur occluded within the passive film is present in multiple oxidation states, including sulfide. The reactivity of the lithium metal surface with O/sub 2/, CO/sub 2/, CO, and N/sub 2/ was studied. The 'black spots' were synthesized and analyzed as a lithium oxynitride. A model for ion transport across the passivating lithium chloride film was postulated and its implications discussed. The current interrupt method was tested on a model system. An A/D interface and associated software was developed to enable rapid, accurate data acquisition.
The primary goal of this research was to determine the effect of environment upon toughening and strength in commercially available transformation-toughened ceramics (partially stabilized ZrO{sub 2} (PSZ) and dispersion toughened Al{sub 2}O{sub 3} (DTA)). Emphasis was on understanding the mechanism(s) responsible for environmentally induced strength degradation in the temperature range of 25 to 1050{degree}C. Dynamic fatigue techniques (four-point flexural strength as a function of stressing rate) were used in a three-phase plan to investigate fracture strength and slow crack growth in environments containing controlled amounts of water vapor. Similar measurements were also conducted in inert atmospheres (dry N{sub 2}) to distinguish intrinsic effects from environmentally derived effects. In addition, the effects of aging (extended exposure at elevated temperatures and selected atmosphere conditions) on the candidate materials at low temperatures were studied. The activities pursued and the results obtained are described in this report. 40 refs., 53 figs., 22 tabs.
