UNLV Theses, Dissertations, Professional Papers, and Capstones 5-1-2015 High Pressure Behavior of Mullite-Type Oxides: Phase Transitions, Amorphization, Negative Linear Compressibility and Microstructural Implications Patricia Kalita University of Nevada, Las Vegas Follow this and additional works at: https://digitalscholarship.unlv.edu/thesesdissertations Part of the Ceramic Materials Commons, Condensed Matter Physics Commons, and the Engineering Science and Materials Commons Repository Citation Kalita, Patricia, "High Pressure Behavior of Mullite-Type Oxides: Phase Transitions, Amorphization, Negative Linear Compressibility and Microstructural Implications" (2015). UNLV Theses, Dissertations, Professional Papers, and Capstones. 2369. http://dx.doi.org/10.34917/7645928 This Dissertation is protected by copyright and/or related rights. It has been brought to you by Digital Scholarship@UNLV with permission from the rights-holder(s). You are free to use this Dissertation in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s) directly, unless additional rights are indicated by a Creative Commons license in the record and/or on the work itself. This Dissertation has been accepted for inclusion in UNLV Theses, Dissertations, Professional Papers, and Capstones by an authorized administrator of Digital Scholarship@UNLV. For more information, please contact [email protected]. HIGH PRESSURE BEHAVIOR OF MULLITE-TYPE OXIDES: PHASE TRANSITIONS, AMORPHIZATION, NEGATIVE LINEAR COMPRESSIBILITY AND MICROSTRUCTURAL IMPLICATIONS by Patricia E. Kalita Bachelor of Sciences in Physics University of Nevada Las Vegas 2006 Master of Sciences in Physics University of Nevada Las Vegas 2008 A dissertation submitted in partial fulfillment of the requirements for the Doctor of Philosophy – Physics Department of Physics and Astronomy College of Sciences Graduate College University of Nevada, Las Vegas May 2015 Copyright by Patricia E. Kalita, 2015 All Rights Reserved We recommend the dissertation prepared under our supervision by Patricia E. Kalita entitled High Pressure Behavior of Mullite-Type Oxides: Phase Transitions, Amorphization, Negative Linear Compressibility and Microstructural Implications is approved in partial fulfillment of the requirements for the degree of Doctor of Philosophy - Physics Department of Physics and Astronomy Andrew Cornelius, Ph.D., Committee Chair Yusheng Zhao, Ph.D., Committee Member Leonard Zane, Ph.D., Committee Member Stanislav Sinogeikin, Ph.D., Committee Member Hartmut Schneider, Ph.D., Committee Member Wanda Taylor, Ph.D., Graduate College Representative Kathryn Hausbeck Korgan, Ph.D., Interim Dean of the Graduate College May 2015 ii ABSTRACT Even though mullite occurs rarely in nature, it is perhaps one of the most important phases in both traditional and advanced ceramics. Existing and emerging applications of mullite and mullite-type materials include: high-temperature composites, aerospace materials, ballistic shielding for military applications and even non-linear optical materials. There are many uncertainties regarding the basic physical properties of mullite-type materials, particularly in terms of their high-pressure structural stability and mechanical behavior that are important to address for emerging applications of mullites as engineering materials. This work is the first reported comprehensive investigation of the high –pressure structural behavior of several different mullites and synthetic mullite-type oxides. The materials investigated are representatives of different structural and chemistry branches of the mullite family. The goal is to elucidate how the most fundamental building blocks of mullite oxides accommodate high pressure compression. Mullites and mullite-type oxides are investigated at extreme pressures using synchrotron x-ray diffraction and laser Raman spectroscopy. These experiments enable the extraction of the materials’ structure and its modifications in a function of increasing pressure: deformation of polyhedra, phase transitions, formation and breaking of bonds. The experimental techniques used here are ideally suited to provide a synergical interplay in the study of oxides under high-pressure conditions: Raman spectroscopy is a technique for investigating short range order phenomena while x-ray diffraction accesses structural changes occurring at the long range order. The following phenomena are discussed: phase transitions, equations of state, pressure-driven amorphization, and the very rare effect of negative linear compressibility. The unprecedented discovery of negative linear compressibility in mullite-type oxides presented here opens the door to military applications as incompressible optical materials. iii ACKNOWLEDGEMENTS I would like to express my deepest appreciation to my outstanding committee chair and advisor, Prof. Andrew Cornelius for continuously supporting my research endeavors and giving me independence in taking the research project in new directions. I would also like to express my deepest gratitude to Dr. Stanislav Sinogeikin for being an extraordinary mentor in my research at the Advanced Photon Source. In addition a big thank you goes to Prof. Hartmut Schneider for introducing me to the fascinating world of mullite materials. Many heartfelt thanks go to my entire committee: Prof. Andrew Cornelius, Dr. Stanislav Sinogeikin, Prof. Hartmut Schneider, Prof. Wanda Taylor, Prof. Leonard Zane, and Prof. Yusheng Zhao. Work at UNLV is supported by DOE award no. DEFG36-05GO08502. UNLV HiPSEC is supported by the US DOE, NNSA, under Agreement DEFC08- 01NV14049. Portions of this work were performed at HPCAT (Sector 16), Advanced Photon Source (APS), Argonne National Laboratory. HPCAT operations are supported by DOE-NNSA under Award No. DE- NA0001974 and DOE-BES under Award No. DE-FG02-99ER45775, with partial instrumentation funding by NSF. APS is supported by DOE-BES, under Contract No. DE- AC02-06CH11357. Use of the APS was supported by DOE-BES, Contract W-31-109-ENG- 38.). FAME-Tech Labs, UNLV are supported by DOEEERE under Award No. DE-FG 3606GO8636 and Award No. EE-0000269. The author acknowledges the use of the gas-loading facility of GSECARS–COMPRESS. iv DEDICATION I dedicate this dissertation work to my family and friends for their encouragements, cheerleading and all the support throughout the process. I special feeling of gratitude goes to Prof. Kris Lipinska who has the attitude and the substance of a genius: she continually and convincingly conveyed a spirit of adventure and excitement in regard to research and scholarship and in doing so made it possible for me to successfully complete this endeavor. v TABLE OF CONTENTS ABSTRACT ................................................................................................................................. III ACKNOWLEDGEMENTS.......................................................................................................... IV DEDICATION ............................................................................................................................... V TABLE OF CONTENTS ............................................................................................................. VI LIST OF TABLES ........................................................................................................................ IX LIST OF FIGURES ....................................................................................................................... X CHAPTER 1 - INTRODUCTION .............................................................................................. 1 CHAPTER 2 – BACKGROUND ................................................................................................. 4 2.1. DESCRIPTION OF MULLITES AND THEIR APPLICATIONS............................... 4 2.1.1. Alumino-Silicate Mullites ........................................................................................................ 4 2.1.1.1. Objectives of high-pressure studies of alumino-silicate mullites. ............................................. 5 2.1.1.2. Previous studies of aluminosilicate mullites and of sillimanite. ................................................ 5 2.1.2. Boron Mullite .......................................................................................................................... 6 2.1.3. PbMBO4 Synthetic Mullites ..................................................................................................... 8 2.1.4. How Do the Investigated Materials Relate to Each Other? ...................................................... 9 2.2. RAMAN SPECTROSCOPY ........................................................................................... 11 2.2.1. A Brief History of the Raman Effect ....................................................................................... 12 2.2.2. What is the Raman Effect? .................................................................................................... 14 2.2.3. Limitations of Raman Spectroscopy. ...................................................................................... 16 2.2.4. States of a System – Vibration of a Diatomic Molecule.......................................................... 17 2.2.5. Classical Light Scattering - Rayleigh Theory ........................................................................... 22 2.2.6. Theory of Raman Scattering - Overview