Sarin Research Group
In-Situ High Temperature Materials Research
Ceramic materials are attractive for many high temperature applications , including thermal protection systems for combustors or aero-engines, for stationary gas turbines, and for re-entry space vehicles, heavy duty burner tubes, heat exchangers, hot gas filters, catalytic converter supports, and chemical reactors. Most, if not all, of the above applications are directly geared towards improving energy efficiency of high temperature processes or reducing their impact on the environment (e.g. reducing NOx emissions). These materials must meet stringent property requirements which are dictated by the specifics of the applications and may include resistance to chemical attack, high temperature stability, high temperature oxidation resistance, high strength/weight ratios, thermal expansion match with other components, etc.
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Materials for High Temperature Applications
A wide spectrum of materials for advanced high temperature applications are being researched and include both oxide ceramics as well as diborides. Different investigations have explored (a) the oxidation behavior of ultra-high temperature ceramics (UHTC) and their composites through novel experiments, (b) fine-tuning of thermal expansion of materials (e.g. mullite, pollucite) (c) anisotropic thermal expansion properties of low symmetry crystalline oxide ceramic phases, as well as (d) the kinetics of microstructure evolution of templated mullite fibers as a function of composition and temperature. One unique aspect of these studies has been the evaluation of the materials and their properties in situ, at high temperatures in their anticipated work environment.
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Phase Transformation Systems in Oxide Ceramics
There is a genuine need to understand the phase transformation behavior of ceramic oxide materials at high temperatures. The phase transformation property of some materials is useful in selected technological applications, however, an in-depth understanding of the mechanism of phase transformations in crystalline ceramic oxide materials can be invaluable in designing novel materials with advanced functionalities for future applications including (a) energy generation (b) aerospace (c) defense (d) sensors and actuators, (e) automobiles and (f) biomedical applications.
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Instrumentation for In-Situ High Temperature Characterization of Material Properties
Ceramics are the materials of choice for use in extremely demanding high temperature applications. It is important to understand the behavior and performance of ceramic materials in their anticipated working environment. In order to characterize material properties in situ, at high temperature in air, different instruments were developed and include (a) the Curved Image Plate Detector for rapid, high resolution, synchrotron X-ray diffraction (XRD) data acquisition, (b) a quadrupole lamp furnace (QLF) which allows high temperature XRD experiments to be conducted in air up to 2000°C and (c) high temperature tensile testing apparatus for monofilament fibers. The performance, reliability, accuracy and the reproducibility of the methods and the instruments were demonstrated using standard materials.