Electrical Field Assisted Sintering (EFAS) has shown impressive results in obtaining nanostructured materials, but how does it work?In this collaboration with Prof. van Benthem's Laboratory, we are addressing the thermodynamic effects of an electric field during sintering, and correlating this with unique in-situ TEM analysis of the process. By measuring the grain boundary energy by calorimetry in a novel approach developed by our laboratories, we have recently observed that the grain boundaries generated from the EFAS and from conventional sintering are indeed energetically significantly different. Magnesium aluminate and tin dioxide are among the studied materials, but much is still to be done.
Improving the Control of Densification in Nanoceramics using ThermodynamicsCeramic materials often exhibit novel physical and chemical properties as their sizes approach nanometer dimensions. These new properties have inspired a variety of new applications in several fields, ranging from nanosensors to cathode materials for fuel cells and lithium batteries. As well, the possibility is opened for the development of new materials in response to the current energy problems such as the U.S. increasing demand for energy, dependence on foreign oils, and climate change. However, the optimization of nanoceramic processing is still a challenge, and understanding the fundamental concepts requires further research. Within this project, Prof. Castro focuses on the larger volume fraction of interfaces present in nanoceramics to improve processing control. This work is supported by NSF DMR CERAMICS 1055504.
Nanostructured materials are likely to play a large role in future nuclear reactors and radioactive waste storage due to their strength and potential resistance to structural damage from radiation. However, this potential is hindered by significant gaps in the understanding of interfaces' properties and their role in the overall performance of the nanocrystalline structures. The lack of reliable thermodynamical data of nanomaterials makes it extremely difficult to predict and fully exploit nanomaterials' properties in high-radiation environments, this being one of the major reasons why the stability of the nanomaterials is still a big unresolved question. The goal of this project is to investigate nanomaterials with potential interest for nuclear components [the aluminate based spinels (MAl2O4, M = Mg, Ni, or Zn), investigate zirconia based materials (ZrO2 doped with Mg, Y, or Ca), and establish the link between composition, interface thermodynamics, and radiation resistance, aiming to enable a better understanding of the nature of enhanced performance in nanocrystalline ceramics. Thereafter, we will exploit the achieved knowledge as a foundation in order to design a new nanocomposite ceramic capable of withstanding high radiation exposition by using elements of interface engineering on a thermodynamic basis. This project is in collaboration with the Los Alamos National Laboratory and is supported by the US Department of Energy, division of Basic Energy Sciences. Materials Design Institute also support a parallel research.
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