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In Situ Synchrotron Studies of Oxide Ceramics to 3,000°C

MATERIALS SEMINAR
Department of Materials Science & Engineering
Tuesday November 19, 2019
2:15 – 3:15PM ~ SERF 307
Please join us for refreshments at 2:10


"In Situ Synchrotron Studies of Oxide Ceramics to 3,000°C"

Speaker: Dr. Waltraud Kriven
Willett Professor Materials Science & Engineering
University of Illinois at Urbana-Champaign-Champaign, IL

Abstract:
A quadrupole halogen lamp furnace (QLF) capable of heating to 2,000°C in air has been developed in our laboratory, in collaboration with Dr. Julius Schneider at the Ludwig Maximillian University in München, Germany. A conical nozzle levitator (CNL) developed by Dr. Richard Weber at Materials Modification in Chicago, Illinois is capable of in situ XRD measurements of oxides to 3,000°C in air or controlled atmosphere. These two instruments were used at the Advanced Photon Sources (APS) at the Argonne National Laboratory, and the QLF was used at the National Synchrotron Light Source II (NSLSII) at Brookhaven National Laboratory to carry out the following experiments: (i) Thermal expansion measurements in 3-D (ii) Solid state phase transformations (iii) Solid state chemical reactions (iv) In situ determination of phase diagrams. 
    A variety of ceramic and mineral examples are provided to illustrate the seven crystal systems (cubic, tetragonal, orthorhombic, rhombohedral, hexagonal, monoclinic and triclinic). Computer software (Program CTEAS) has been developed to visualize the thermal evolution in 3-D for individual {hkl} planes, principal strain directions and whether they are increasing or decreasing. When a crystal undergoes a phase transformation upon heating, the 3D crystal structural, lattice correspondence between the parent and product phases can be identified from the continuity of thermal expansion for planes in the parent phase which approximately “become” planes in the product phase. The example is given of a peritectic reaction in the binary HfO2-Ta2O5 system where Hf6Ta2O17 decomposes on heating into liquid HfO2-Ta2O5 solid solution plus HfO2 at 2242 ± 16 °C. A Z = 4, pseudo-sub-cell is identified which is common to the parent and product phases, which, coupled with vector analysis identifies a lattice correspondence between them, and hence possible orientation relationship. 
A systematic approach to the rapid production of the high temperature, ternary HfO2-Ta2O5-TiO2 phase diagrams is presented. This study highlights the combined use of: (i) in-situ high temperature X-ray diffraction on heating to 2,000°C in the QLF, as well as on cooling of liquidi from 3000 ˚C in air in the CNL, and (ii) extraction of common atomic motifs with associated material symmetry analysis. The HfO2-Ta2O5-TiO2 ternary phase diagram has four congruently melting compounds: HfO2, Ta2O5, TiO2 and TiTa2O7 and two incongruently melting compounds: Hf6Ta2O17 and HfTiO4. There are no ternary congruently melting compounds. Finally, ten invariant reactions were identified in this phase space.


Biography:
Waltraud M. Kriven received a PhD in 1976 in Solid State Chemistry from the University of Adelaide in South Australia. The B.Sc. (Hons) and Baccalaureate degrees were in Physical and Inorganic Chemistry, and Biochemistry, also in Adelaide. Dr. Kriven spent one year as a Post-Doctoral Teaching and Research Fellow in the Chemistry Dept. at the University of Western Ontario in Canada. She then spent three years (1977-1980) jointly at the University of California at Berkeley, and at the Lawrence Berkeley Laboratory. There, Dr. Kriven conducted post-doctoral research in transmission electron microscopy of ceramics and was a Lecturer, teaching Phase Equilibria in the senior undergraduate Ceramics Program of the Dept. of Materials Science and Mineral Engineering. For (1980-1984) Dr. Kriven was a Visiting Scientist at the Max-Planck-Institute in Stuttgart, Germany. Since 1984, Professor Kriven has been at the University of Illinois at Urbana-Champaign. She is a Full Professor and has held joint faculty positions in the Materials Research Laboratory (initially) and the Department of Materials Science and Engineering. She is also an Affiliate Professor in the Department of Mechanical Science and Engineering at UIUC.
Professor Kriven has internationally recognized expertise in the areas of geopolymers, phase transformations in inorganic compounds and their applications in structural ceramic composites, and low temperature synthesis of oxide ceramic powders. In addition, she has made extensive contributions to oxide composites design, microstructure characterization by electron microscopy techniques and phase equilibria. Professor Kriven has been elected an Academician to the World Academy of Ceramics (2005), Fellow of the American Ceramic Society (1995) and Fellow of the Australian Ceramic Society (2009). In 2017 she was chosen for the James A. Mueller Award in the Engineering Division of the American Ceramic Society. Professor Kriven was a Past-Chair and Counselor to the Engineering Ceramics Division of the American Ceramic Society. She has organized ongoing 20 annual symposia on geopolymers and 5 annual symposia on Phase Transformations in Ceramics: Science and Applications for the American Ceramic Society and MS&T Conferences, as well as several international symposia on geopolymers.


Faculty Host: Dr. Claudia Rawn
 

Tuesday, November 19 at 2:10pm to 3:15pm

Science and Engineering Research Facility (SERF), 307
1414 Circle Dr, Knoxville, TN 37996

Event Type

Lectures & Presentations

Topic

Engineering

Audience

Current Students, Faculty & Staff

Tags

MSE Seminar

Department

Materials Science and Engineering

Hashtag

#KrivenSeminar

Contact Name

Ashley Cole

Contact Email

acole14@utk.edu

Contact Phone

865-974-5336

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