titanium niobium oxides by changcheng john wang a thesis submitted to the faculty of alfred ...

124 Pages·2014·3.03 MB·English

by  Changcheng John Wang

TITANIUM NIOBIUM OXIDES
BY
CHANGCHENG JOHN WANG
A THESIS
SUBMITTED TO THE FACULTY OF
ALFRED UNIVERSITY
IN PARTIAL FULFILLMENT OF THE REQUIREMENTS
FOR THE DEGREE OF
MASTER OF SCIENCE
IN
MATERIALS SCIENCE AND ENGINEERING
ALFRED, NEW YORK
JUNE, 2014
Alfred University theses are copyright protected and
may be used for education or personal research only.
Reproduction or distribution in part or whole is
prohibited without written permission from the author.
Signature page may be viewed at Scholes Library,
New York State College of Ceramics, Alfred University,
Alfred, New York.
TITANIUM NIOBIUM OXIDES
BY
CHANGCHENG JOHN WANG
B.S. ALFRED UNIVERSITY (2009)
SIGNATURE OF AUTHOR
APPROVED BY
NATHAN MELLOTT, ADVISOR
DOREEN D. EDWARDS, ADVISORY COMMITTEE
SCOTT MISTURE, ADVISORY COMMITTEE
CHAIR, ORAL THESIS DEFENSE
ACCEPTED BY
DOREEN D. EDWARDS, DEAN
KAZUO INAMORI SCHOOL OF ENGINEERING
ACKNOWLEDGMENTS
I would like to thank my advisor, Dr. Nathan Mellott, for his guidance and advice
throughout the graduate studies. His patience and persistence allow me to continuously
improve. I would also like to thank my thesis committee members, Dr. Scott Misture and
Dr. Doreen Edwards. Their suggestions during the research are greatly appreciated.
Several classmates in Dr. Mellott’s lab helped me, including Brian Adams, Anthony
Munto and Dimple Pradhan. Mr. Swavek Zdzieszynski and Gerald L. Wynick also
provided their assistance in the characterizations. I would also like to thank Terry Guild,
Hyojin Lee, Jaime Babcock and NYSCC physical plant, John Rich, Martha Mueller, Pat
LaCourse, Catlin Aramburu, Natalie Skwarek and Francesca Maiden.

This work is partially funded by US DOE Renewable Energy Labs.
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TABLE OF CONTENTS
Page
Acknowledgments .................................................................................................... iii
Table of Contents ..................................................................................................... iv
List of Tables ............................................................................................................ vi
List of Figures ......................................................................................................... vii
Abstract ..................................................................................................................... x
I INTRODUCTION ................................................................................................... 1
A. Motivation and Statement of Objectives ....................................................................... 1
B. Material Systems of Interest .......................................................................................... 1
1. Titanium Dioxides ..............................................................................................................1
2. Niobium Oxides ..................................................................................................................2
3. Titanium Niobium Oxides ..................................................................................................2
C. Sol-gel Processing ......................................................................................................... 3
1. Introduction ........................................................................................................................3
2. Advantages and Disadvantages of Sol-Gel Processing .......................................................5
3. Oxide Systems formed by Sol-Gel Processing ...................................................................5
D. X-Ray Diffraction .......................................................................................................... 6
1. Introduction ........................................................................................................................6
2. Principles ............................................................................................................................7
3. Applications of X-ray Diffraction .......................................................................................7
4. Rietveld Refinement ...........................................................................................................8
5. Quantification ................................................................................................................... 10
6. Limitations ........................................................................................................................ 10
II EXPERIMENTAL METHODS ........................................................................... 12
A. Processing .................................................................................................................... 12
B. Sample Analysis Equipment ........................................................................................ 13
1. DTA/TGA ......................................................................................................................... 13
2. HTXRD ............................................................................................................................ 13
3. MDI Jade and Bruker Topas ............................................................................................. 14
III RESULTS ............................................................................................................... 15
A. 100:0 ............................................................................................................................ 15
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B. 75:25 ............................................................................................................................ 20
C. 50:50 ............................................................................................................................ 25
D. 25:75 ............................................................................................................................ 31
E. 0:100 ............................................................................................................................ 35
IV DISCUSSION ........................................................................................................ 41
A. Thermal Analysis ......................................................................................................... 41
1. 100:0 ................................................................................................................................. 41
2. 75:25 ................................................................................................................................. 42
3. 50:50 ................................................................................................................................. 42
4. 25:75 ................................................................................................................................. 43
5. 0:100 ................................................................................................................................. 44
B. Ti:Nb Metal Ion Ratio Influence on Phase Assemblage .............................................. 45
C. Crystallization Temperature Influence on Phase Assemblage..................................... 48
D. Phase Transformation Temperatures Influence on Phase Assemblage ....................... 50
E. Phase Diagram Comparison ........................................................................................ 53
V CONCLUSIONS .................................................................................................... 57
VI FUTURE WORK .................................................................................................. 58
REFERENCES ................................................................................................................ 59
APPENDIX ...................................................................................................................... 74
A. Appendix A: XRD Patterns from Rietveld Refinement for 100:0 ............................... 77
B. Appendix B: Numerical Values of Lattice Parameters for 100:0 ................................ 79
C. Appendix C: XRD Patterns from Rietveld Refinement for 75:25 ............................... 84
D. Appendix D: Numerical Values of Lattice Parameters for 75:25 ................................ 86
E. Appendix E: XRD Patterns from Rietveld Refinement for 50:50 ............................... 94
F. Appendix F: Numerical Values of Lattice Parameters for 50:50 ................................ 95
G. Appendix G: XRD Patterns from Rietveld Refinement for 25:75 ............................. 101
H. Appendix H: Numerical Values of Lattice Parameters for 25:75 .............................. 103
I. Appendix I: XRD Patterns from Rietveld Refinement for 0:100 .............................. 109
J. Appendix I: Numerical Values of Lattice Parameters for 0:100 ............................... 110
v
LIST OF TABLES
Page
Table I. Mole Percentage of Each Sample Set ............................................................. 12
Table II. Phase Identification of 100:0 as a Function of Temperature ........................... 17
Table III. Phase Identification of 75:25 as a Function of Temperature ........................... 23
Table IV. Phase Identification of 50:50 as a Function of Temperature ........................... 28
Table V. Phase Identification of 25:75 as a Function of Temperature. .......................... 33
Table VI. Phase Identification of 0:100 as a Function of Temperature ........................... 38
Table VII. Shannon Ionic Radii for Ti4+, Nb4+ and Nb5+ with Coordination Number of 6
......................................................................................................................... 45
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LIST OF FIGURES
Page
Figure 1. Illustration of sol-gel process (after Pierre). ...................................................... 4
Figure 2. Sample preparations for different sample sets. ................................................ 13
Figure 3. Differential thermal analysis (DTA) and thermogravimetric analysis (TGA) of
100:0 sample. .................................................................................................. 15
Figure 4. High temperature x-ray diffraction patterns of 100:0 powders from 200ºC to
1100C. ........................................................................................................... 16
Figure 5. High temperature x-ray diffraction patterns of 100:0 powders at 300ºC, 600ºC
and 1100ºC (A: TiO2 Anatase, R: TiO2 Rutile). ............................................. 17
Figure 6. Comparison of 100:0 ex-situ (top) vs. in-situ (bottom) XRD patterns. ........... 18
Figure 7. Crystallite size as a function of temperature for 100:0. ................................... 19
Figure 8. Relative phase percentage as a function of temperature for 100:0. ................. 20
Figure 9. Differential thermal analysis (DTA) and thermogravimetric analysis (TGA) of
75:25 sample. .................................................................................................. 21
Figure 10. High temperature x-ray diffraction patterns of 75:25 powders from 200°C to
1100°C. ........................................................................................................... 22
Figure 11. High temperature x-ray diffraction patterns of as prepared 75:25 powders at
700ºC, 900ºC and 1100ºC (A: TiO Anatase, R: TiO Rutile, : Ti Nb O ,
2 2 2 10 29
▲: TiNb2O7). .................................................................................................. 23
Figure 12. Crystallite size as a function of temperature for 75:25. ................................... 24
Figure 13. Relative phase percentage as a function of temperature for 75:25. ................. 25
Figure 14. Differential thermal analysis (DTA) and thermogravimetric analysis (TGA) of
50:50 sample. .................................................................................................. 26
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Figure 15. High temperature x-ray diffraction patterns of 50:50 powders from 200ºC to
1100°C. ........................................................................................................... 27
Figure 16. High temperature x-ray diffraction patterns of 50:50 powders at 200ºC, 800ºC
and 1100°C (A: TiO2 Anatase, R: TiO2 Rutile, ▲: TiNb2O7). ....................... 28
Figure 17. Crystallite size as a function of temperature for 50:50. ................................... 29
Figure 18. Relative phase percentage as a function of temperature for 50:50. ................ 30
Figure 19. Differential thermal analysis (DTA) and thermogravimetric analysis (TGA) of
25:75 sample. .................................................................................................. 31
Figure 20. High temperature x-ray diffraction patterns of 25:75 powders from 200ºC to
1100 °C. .......................................................................................................... 32
Figure 21. High temperature x-ray diffraction patterns of 25:75 powders at 400ºC, 800ºC
and 1100°C (: Nb2O5 monoclinic, : Nb2O5 orthorhombic, ▲: TiNb2O7). .. 33
Figure 22. Crystallite size as a function of temperature for 25:75. ................................... 34
Figure 23. Relative phase percentage as a function of temperature for 25:75. ................ 35
Figure 24. Differential thermal analysis (DTA) and thermogravimetric analysis (TGA) of
0:100 sample. .................................................................................................. 36
Figure 25. High temperature x-ray diffraction patterns of 0:100 powders from 200ºC to
1100ºC. ............................................................................................................ 37
Figure 26. High temperature x-ray diffraction patterns of 0:100 powders from 400ºC,
700ºC and 1100 °C (: Nb2O5 monoclinic, : Nb2O5 orthorhombic). ............ 38
Figure 27. Crystallite size as a function of temperature for 0:100. ................................... 39
Figure 28. Relative phase percentage as a function of temperature for 0:100. ................ 40
Figure 29. Phase diagram of TiO2-Nb2O5. ........................................................................ 55
Figure 30. Phase assemblage based on Ti:Nb ratio and temperature. .............................. 56
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Figure 31. Microstrain via Williamson-Hull Plot. ............................................................. 75
Figure 32. Measured, calculated, and difference profiles for various scenarios. ............. 76
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