Invited Paper TR+SE-WeM1
Seeing Things as They Really are: In Situ Studies of Materials in Application Environments and the Development of Temperature-Adaptive Nanocomposites

Wednesday, October 31, 2012, 8:00 am, Room 19

In the early 1940s, military pilots and those who serviced their planes were surprised by serious problems with ignition systems and diverse electrical troubles in their state of the art aircraft. Further study revealed that the graphite commutator brushes used in the electrical generator on the airplane (similar to the alternator in our automobiles) were the source of these technical difficulties, because they wore out 100 to 1000 times faster than expected. Over 70 years later, sensitivity of materials at contact interfaces to the extreme ambient environments aircraft are subjected to is still limiting aerospace capability. One of the reasons materials scientists haven’t overcome these problems sooner is because it is difficult to do materials science, at least the part where you correlate performance to structure and composition, when there is such a big difference between the operating environment and the environment in which analysis is conducted. All the materials tribologist can really do is post mortem forensics work on materials designed to get hot after they have cooled down to a convenient handling temperature. During that cooling down time, phase changes and grain growth occur, perhaps misleading the researcher on the compounds or phases yielding high or low friction at interfaces in relative motion. In this talk we will review innovative characterization techniques designed to provide the insight necessary to produce environmentally adaptive tribological coatings, especially materials designed to operate over broad ranges of humidity (i.e, earth to space) and temperature (i.e., ignition to supersonic flight). Characterization of temperature adaptive nanocomposite lubricant materials, such as MoN/Ag and VN/Ag via Raman spectroscopy will be reviewed in depth.