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Materials Science & Engineering News

Seminar September 1, 2017 John McCloy

Reconstructing Vitrified Wallbuilding Technology for pre-Viking Fort Site, Sweden

Nuclear waste must be deposited in such a manner that it does not cause significant impact on the environment or human health. In some cases, the integrity of the repositories will need to sustain for tens to hundreds of thousands of years. In order to ensure such containment, nuclear waste is frequently converted into a very durable glass. It is fundamentally difficult, however, to assure the validity of such containment based on short-term tests alone. To date, some anthropogenic and natural volcanic glasses have been investigated for this purpose. However, glasses produced by ancient cultures for the purpose of joining rocks in stonewalls have not yet been utilized in spite of the fact that they might offer significant insight into the long-term durability of glasses in natural environments. Therefore, a project has been initiated with the scope of obtaining samples and characterizing their environment, as well as to investigate them using a suite of advanced materials characterization techniques. It will be analyzed how the hillfort glasses may have been prepared, and to what extent they have altered under in-situ conditions. The ultimate goals are to obtain a better understanding of the alteration behavior of nuclear waste glasses and its compositional dependence, and thus to improve and validate models for nuclear waste glass corrosion. The presentation summarizes the first stages of the project, and also presents some early findings on fusion of amphibolite and on the process for joining the granite-gneiss stones in the hillfort walls of Broborg, Sweden.

Krishnan Raja: “Solid Solutions of Transition Metal Diborides: Ultra high temperature ceramics and hydrogen evolution catalysts”

Abstract:  Transition metal diborides have very high melting point, metal like electrical conductivity, and good
thermal shock resistance. Therefore, these materials are being investigated as high temperature
electrode materials for use in magneto-hydrodynamic (MHD) direct power extraction from coal fired
plasma. These electrodes will be subject to extreme environmental conditions, including
temperatures in excess of 1500 °C. ZrB2-HfB2 solid solutions potentially meet the requirements to
resist these extreme environments and still function well as an electrode coating material. Due to
their high chemical stability in wide range of aqueous solutions, transition metal borides are
investigated as electro-catalysts for hydrogen evolution reactions. This presentation will describe the
ongoing research activities on metal rich solid solutions of ZrB2-HfB2 system as electrode materials
for MHD direct power extraction and hydrogen evolution.

Bio:  Dr. Raja has been with the University of Idaho, Moscow since August 2011. Currently he is an associate professor of Chemical and Materials Engineering. Dr. Raja is a licensed professional engineer in the Idaho State, and a NACE International (National Association of Corrosion Engineers, USA) certified materials selection and design specialist. He has more than 100 peer reviewed publications in journals and conference proceedings that have been cited more than 2,600 times with an h-index of 23. He was a recipient of a DARPA (Defense Advanced Research Projects Agency) young faculty award in the year 2012. His research Interests are design and synthesis of high temperature and auxetic ceramics, environmental degradation of materials, and synthesis and characterization of materials for energy conversion and storage.