Sandia National Laboratories' surface cleaning and processing R&D program provides coordinated engineering and scientific assessment of traditional and advanced technologies. We recognize that success in controlling interfacial processes is based on an understanding of the initial state of the surface as well as the chemical and physical processes that take place as the interface is modified or ages. We provide the information required to specify surface preparation, surface processing, and contamination control procedures for integration into a component manufacturing process. This program supports a wide range of both fundamental and applied research for the nuclear weapons complex, other U.S. Department of Energy and U.S. Department of Defense customers, and numerous industrial partners.
Surface Cleaning: We focus on quantifying how clean a given surface must be to ensure successful incorporation into a given component. Post-cleaning characterization allows us to determine the extent of cleanliness for the cleaning method(s) in question. These often involve alternate aqueous and nonaqueous solution cleaning chemistries as well as less traditional dry methods including RF plasma and UV ozone. Because cleaning methods are highly materials dependent, we routinely consider the compatibility of the process with the materials system into which the surface will be incorporated. Cleaning efficacy is routinely evaluated using electron (AES and SEM), ion (SIMS), and photon (XPS, FTIR, and Raman) spectroscopies. The selected cleaning approach then is optimized to enable and simplify the component manufacturing process.
Surface Processing: Details of the chemical and physical properties of a surface can greatly impact interfacial phenomena that occur during component manufacture and use. We have engineered a range of surface-processing options that involve solution chemical etching, electrochemical cycling, electrodeposition, controlled atmosphere thermal annealing, and RF plasma sputtering. The resulting surface properties are readily discerned with the use of vacuum-based electron, ion, and photon spectroscopies. Sandia has developed a laboratory in which high-pressure gas phase, high-temperature, and solution environments can be interfaced directly to a commercial electron spectrometer. The specific analytical techniques that are applied include x-ray, ultraviolet and Auger (photo-) electron spectroscopies, and ion scattering and secondary ion mass spectrometries. When performed contiguously with the processing environment, these techniques provide high sensitivity, contaminant-free characterization of the surface during any stage of the process. This approach is well suited for air and moisture-sensitive materials as well as contaminant-free processing.