Journal of the American Ceramic Society Awards Symposium: JACerS Awards Symposium Session I
Program Organizers: William Fahrenholtz, Missouri University of Science and Technology
Wednesday 8:00 AM
October 17, 2018
Location: Greater Columbus Convention Center
Session Chair: William Fahrenholtz, Missouri University of Science and Technology
8:00 AM Introductory Comments
8:20 AM Invited
Scaling Effects in Ferroelectrics: An Old Problem Surpassed by New Materials: Jon Ihlefeld1; 1University of Virginia
Ferroelectrics constitute a technologically important class of electronic ceramics that have enabled advances in many commercial areas: high volumetric density capacitive energy storage, medical ultrasound transducers, and non-volatile computer memory, among many others. As technological advances have driven decreased sizes of virtually every electronic component, size limits have been approached where the properties materials begin to change. In ferroelectrics, these changes include decreased polarizations, decreased permittivities, and increased coercivities. Most of these property changes are detrimental to achieving the desired performance. The causes of these changes can be separated into intrinsic and extrinsic effects. This talk will highlight the state of understanding of extrinsic scaling effects. We will then discuss how a recently discovered ferroelectric material, hafnium oxide, overcomes many of these size scaling challenges and is poised to enable a new generation of ferroelectric-based devices extending size scaling to regimes not thought possible less than 10 years ago.
8:50 AM Invited
Defect Mechanisms in BaTiO3-BiMO3 Ceramics: Nitish Kumar1; Eric Patterson2; TIll Frömling3; Edward Gorzkowski2; Peter Eschbach4; Ian Love4; Michael Müller5; Roger De Souza5; Julie Tucker4; Steven Reese4; David Cann4; 1The University of New South Wales,; 2US Naval Research Laboratory; 3Technische Universität Darmstadt; 4Oregon State University; 5RWTH Aachen
The addition of BiMO3 to p-type BT is accompanied by significant improvement in insulation properties, often leading to an n-type behavior in BT-BiMO3 ceramics. It will be shown that donor doping can originate primarily due to two factors—the presence of secondary phases which modifies the stoichiometry of the perovskite phase to become rich in high valence cations, and an increased oxygen vacancy concentration. It was proposed that these defects had an effect of shifting the conductivity minima to higher pO2 values in the Kröger-Vink diagram, as a means to explain both the higher resistivity values and shift to n-type behavior while still showing a near-intrinsic activation energy. For BT-25BZT, a thorough examination of oxygen stoichiometry determined that oxygen vacancy concentrations ranged between 4.0 and 6.3%. A robust defect chemistry model for BT- BiMO3 ceramics is expected to aid in engineering the material for high performance capacitor applications.
9:20 AM Invited
Toward Tunable and Bright Deep-red Persistent Luminescence of Cr3+ in Garnets: Jian Xu1; Jumpei Ueda1; Setsuhisa Tanabe1; 1Kyoto University
Recently, the potential applications of deep-red or NIR persistent phosphors have expanded from night vision security signs to new generation excitation-free & autofluorescence-free biomedical imaging. Cr3+ doped persistent phosphors are considered to be highly desirable candidates since the 3d3 electron configuration of Cr3+ ions allows a narrow-band emission around 700 nm due to the 2E→4A2 spin-forbidden transition (R-line) or a broad-band emission due to the 4T2→4A2 spin-allowed transition, both of which match well with the biological transparent window. Herein, we take several Cr3+ doped garnet hosts as a vivid example to introduce how to design suitable persistent phosphors utilizing the “crystal field engineering” of Cr3+ emission based on Tanabe-Sugano (d3) diagram and how to choose proper lanthanide ions as co-doping sensitizers to further enhance the Cr3+ persistent luminescence by constructing the host referred binding energy (HRBE) diagram as a powerful theoretical prediction tool.
9:50 AM Break
10:20 AM Invited
Cements in the 21st Century: Challenges, Perspectives, and Opportunities: Joseph Biernacki1; Jeffrey Bullard2; Gaurav Sant3; Kevin Brown4; Fredrik Glasser5; Scott Jones2; Tyler Ley6; Richard Livingston7; Luc Nicoleau8; Jan Olek9; Florence Sanchez4; Rouzbeh Shahsavari10; Paul Stutzman2; Konstantine Sobolev11; Tracie Prater12; 1Tennessee Technolgoical University; 2NIST; 3UCLA; 4Vanderbilt University; 5University of Aberdeen ; 6Oklahoma State University; 7University of Maryland; 8BASF; 9Purdue University; 10Rice University; 11University of Wisconsin Milwaukee; 12NASA
Since its widespread use in concrete began over 100 years ago, the chemical composition and physical properties of portland cement have changed only incrementally in response to competing pressures of constructability and cost. These same demands remain today, but newer global megatrend forces are pushing the industry toward more automated construction sustainable concrete materials that generate lower CO2 and have longer service life. These demands are causing the industry to develop construction technologies and cement binder systems that go well outside the bounds for traditional portland cement. This presentation examines the relationship between global megatrends and cement production and use. Seven scientific or technological pathways are identified that will be critical for enabling the needed transformational changes in cement and concrete construction: (1) additive manufacturing, (2) designer admixtures, (3) curated data repositories, (4) computational design, (5) big data and smart materials, (6) alternative binder compositions, and (6) next-generation instrumentation.
10:50 AM Invited
Rate Controls on Silicate Dissolution in Aqueous Environments: Gaurav Sant1; Mathieu Bauchy1; 1University of California Los Angeles
The dissolution of silicates is of importance in engineered, geological and biological systems. Recently, a pioneering combination of nanoscale-resolved measurements of dissolution rates using vertical scanning interferometry and molecular dynamics simulations has revealed that silicate dissolution is foundationally dependent on the rigidity (connectivity) of their atomic networks. An Arrhenius-like expression captures the dependence between silicate dissolution rates and the average number of constraints placed on a central atom in a network and highlights that the energy required for the rupture of a unit constraint is 25 ± 3 kJ/mol across a range of silicate glasses and crystals that feature different levels of polymerization. This understanding helps rationalize dissolution processes within a consistent thermodynamic framework based on the energy of bond rupture, and, harmonizes our understanding of the origins of silicate reactivity, and alterations therein in applications ranging from silicate cements, to damage induced in structural materials in radiation exposure environments.
11:20 AM Invited
Ceramic Waste Form Performance and Degradation: Mechanistic Understandings: Jie Lian1; 1Rensselaer Polytechnic Institute
Effective management of short-lived Cs-137 and Sr-99 radionuclides as the major heat generators and long-lived highly volatile I-129 and Cl-36 is critical for the sustainable development of nuclear energy systems. This talk discusses the recent development of advanced ceramic waste forms for critical radionuclides I, Cs and Cl and their long term performance. Advanced technologies such as spark plasma sintering are used to incorporate and consolidate the critical radionuclides into the dense ceramic waste forms. The thermal stability of the designed waste forms and their chemical durability as evaluated by water dissolution are conducted to achieve mechanistic understanding of waste form performance. In-situ synchrotron X-ray diffraction and environmental scanning electron microscopy observations are also performed to understand the phase transformation and dissolution behaviors. The impacts and implication of the designed ceramic waste forms on effective management of environmental wastes, particularly highly volatile iodine and chlorine, are further highlighted.