In Operando SPM: variable pressure and temperature

Materials behavior is often dominated by highly localized phenomena, and the ability to probe those properties for engineering devices is critical. Often these devices are operating in environments with large differences in temperature and pressure: from the high vacuum and cold of space to the high temperature and high pressure inside a deep water oil well. Here, a transducer capable of measuring the nanomechanical properties under a wide range of temperatures and pressures is proposed, in conjunction with a rapid scanning stage, and variable pressure chamber for the mapping of material properties from cryogenic to 1000C and from milliTorr to kiloTorr. This will combine cutting edge data acquisition, thorough system calibration, and transducer design in Phase I, for the production of a next generation nanomechanical measurement instrument occurring in Phase II. Scanning probe modes will include quantitative stiffness/modulus mapping, force-volume, conductance, and thermal resistance mapping. Stiffness mapping will be achieved using a small amplitude force and displacement signal to measure the true contact stiffness/modulus. Force-volume measurements will be performed using the throw integral to the transducer, allowing approach distances as high as a micrometer or as low as a few nanometers. Conductance mapping can be achieved by biasing the sample or the probe, while thermal resistance and simple calorimetry are accomplished using a very low mass thermal sensor. In addition, the system will be capable of nanomechanical testing in both forward (indentation, compression) and reverse (tensile) modes. Many researchers in energy related fields have expressed a clear need for state of the art technology instrumentation to study the limits of materials. The broader impacts of such an SPM platform proposed here is that researchers from a variety of research areas; catalysis, mechanics of materials under extreme conditions, solid oxide fuel cells, and solar cells, will be able to utilize these new capabilities. Summary for Members of Congress: Materials engineering is backbone of the new industrial revolution, providing the structure to American products; from advanced semiconductors, fuel cells, and batteries to nanocomposite tires and single crystal turbine blades. A high temperature, variable pressure nanomechanical SPM provides researchers the equipment required for 21st century materials exploration.