Solid state reactions in electroceramic systems [Elektronische Ressource] / von Andriy Lotnyk

Sujets

• Physik

Informations

• Publié par: martin-luther-universitat_halle-wittenberg
• Publié le: 01 janvier 2007
• Nombre de lectures: 35
• Langue: English
• Poids de l'ouvrage: 37 Mo

Extrait

Solid state reactions in electroceramic systems
Dissertation
zur Erlangung des akademischen Grades
doctor rerum naturalium (Dr. rer. nat.)
vorgelegt der
Naturwissenschaftlichen Fakultät II
der Martin-Luther-Universität Halle-Wittenberg
von Herrn Andriy Lotnyk
geb. am 16.03.1980 in Kupjansk (Ukraine)
Gutachter:
1. Prof. Dr. Dietrich Hesse, MPI für Mikrostrukturphysik, Halle, Germany
2. Prof. Dr. Hans-Peter Abicht, Martin-Luther-Universität Halle-Wittenberg, Halle, Germany
3. Dr. Vincenzo Buscaglia (Head of Group), National Research Council, Genoa, Italy
Halle (Saale), 26 April 2007
verteidigt am 6 November 2007
urn:nbn:de:gbv:3-000012648
[http://nbn-resolving.de/urn/resolver.pl?urn=nbn%3Ade%3Agbv%3A3-000012648]Dedicated to my lovely wife Svitlana and my son VolodymyrContents
1 Introduction 1
2 Literature review 4
2.1 Thin film solid state reactions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1.1 Thermodynamic model . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.1.2 Nucleation-controlled model . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.1.3 Kinetic model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.2 Synthesis of BaTiO ceramics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
2.2.1 Crystal structure and some properties of TiO . . . . . . . . . . . . . . . . 82
2.2.2 Crystal structure of BaCO , BaTiO and Ba TiO . . . . . . . . . . . . . . 103 3 2 4
A. BaCO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
B. BaTiO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
C. Ba TiO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122 4
2.2.3 Formation of BaTiO from BaCO and TiO by solid state reactions . . . . 133 3 2
2.2.4 Ti-rich barium titanates . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
A. Phase diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
B. Crystal structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
2.3 The system SrO-TiO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192
2.4 The system CaO-TiO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202
2.5 The system MgO-TiO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212
2.6 Modeling of powder reactions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
3 Experimental and investigation procedures 24
3.1 Sample preparations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
3.2 X-ray diffraction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
3.2.1 Basic principles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
3.2.2 XRD analysis performed in this work . . . . . . . . . . . . . . . . . . . . 27
3.3 Transmission electron microscopy . . . . . . . . . . . . . . . . . . . . . . . . . . 30
3.3.1 Basic concepts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
3.3.2 TEM sample preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
3.4 Atomic force microscopy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
4 Results 34
4.1 Solid state reactions of BaCO and BaO with TiO (rutile) . . . . . . . . . . . . . 343 2
4.1.1 Solid-solid reaction of BaCO with TiO (rutile) . . . . . . . . . . . . . . 343 2
A. Some properties of BaCO thin films . . . . . . . . . . . . . . . . . . . 343Contents ii
B. Phase formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
4.1.2 Vapour-solid reaction of BaO with TiO (rutile) . . . . . . . . . . . . . . . 412
A. Phase formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
◦B. Initial stage of vapour-solid reaction at 900 C . . . . . . . . . . . . . . 44
4.1.3 Orientation relationships . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
A. Orientation of Ba TiO . . . . . . . . . . . . . . . . . . . . . . . . . . 462 4
B. Orientation of BaTiO . . . . . . . . . . . . . . . . . . . . . . . . . . . 483
C. Orientations of Ti-rich phases . . . . . . . . . . . . . . . . . . . . . . . 57
4.2 Solid state reactions of BaCO and BaO with TiO (anatase) . . . . . . . . . . . . 583 2
4.2.1 Epitaxial growth of TiO anatase thin films . . . . . . . . . . . . . . . . . 582
A. TiO film growth on (100) SrTiO and (100) LaAlO . . . . . . . . . . 582 3 3
B. TiO film growth on (110) SrTiO and (110) LaAlO . . . . . . . . . . 612 3 3
C. Origin of the epitaxy between TiO (anatase) and SrTiO /LaAlO . . . . 642 3 3
4.2.2 Phase formation and orientation relationships . . . . . . . . . . . . . . . . 66
A. Phase formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
B. Orientation relationships . . . . . . . . . . . . . . . . . . . . . . . . . 67
4.3 Solid state reactions of other alkaline-earth oxides with TiO (rutile) . . . . . . . . 712
4.3.1 Vapour-solid reaction of SrO with TiO (rutile) . . . . . . . . . . . . . . . 712
4.3.2 Vapour-solid reaction of CaO with TiO (rutile) . . . . . . . . . . . . . . . 732
A. Phase formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
B. Orientation relationships . . . . . . . . . . . . . . . . . . . . . . . . . 75
4.3.3 Vapour-solid reaction of MgO with TiO (rutile) . . . . . . . . . . . . . . 772
5 Discussion 79
5.1 The reaction systems BaCO -TiO and BaO-TiO . . . . . . . . . . . . . . . . . . 793 2 2
5.1.1 Phase formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
A. Solid-solid reaction of BaCO with TiO . . . . . . . . . . . . . . . . . 793 2
B. Vapour-solid reaction of BaO vapour with TiO . . . . . . . . . . . . . 822
5.1.2 Orientation relationships . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
A. Orientation of Ba TiO on TiO (rutile) . . . . . . . . . . . . . . . . . 842 4 2
B. Orientations of BaTiO on TiO (rutile) . . . . . . . . . . . . . . . . . 843 2
C. Orientations of BaTiO on TiO (anatase) . . . . . . . . . . . . . . . . 893 2
D. Orientations of Ti-rich phases on TiO (rutile) . . . . . . . . . . . . . . 902
◦5.1.3 Reaction of BaO vapour with TiO surfaces at 900 C . . . . . . . . . . . 912
A. Reaction mechanism . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
B. Void formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
5.2 The reaction systems SrO-TiO , CaO-TiO and MgO-TiO . . . . . . . . . . . . . 932 2 2
5.2.1 Orientation of SrTiO on TiO (rutile) . . . . . . . . . . . . . . . . . . . . 933 2
5.2.2 Orientation of CaTiO on TiO (rutile) . . . . . . . . . . . . . . . . . . . . 933 2
5.2.3 Orientation of MgTiO on TiO (rutile) . . . . . . . . . . . . . . . . . . . 943 2Contents iii
5.3 Factors influencing the first-phase selection in complex oxide thin film systems . . 95
6 Conclusions 98
Bibliography Bib 1
Appendix A 1
Eidesstattliche Erklärung
Acknowledgments
Curriculum Vitae
List of publications
Conference contributions1 Introduction
Solid state reactions in ceramic materials are investigated since many years under both fundamental
1–4and technological points of view. Under working conditions, many devices consisting of multi-
phase or multilayered ceramics are often subjected to high temperatures. As a result, interfacial
solid state reactions may occur between the components. Such reactions occurring on the nano-
meter scale may affect the desired properties of the devices, because chemical and physical pro-
perties of interfaces are changed. Thus, in order to optimise the properties of the existing materials
as well as to produce new materials with desired properties, advanced knowledge of thin film solid
state reactions is required.
Model experiments are well suited to study various aspects of complex solid state reactions.
In this approach, instead of using polycrystalline materials, one reactant is a bulk single crys-
tal. In such model experiments, the formation and orientation of the reaction products can well
be characterised by several structural techniques such as X-ray diffractometry (XRD) and trans-
mission electron microscopy (TEM). This approach has successfully been used by several research
5–11groups to study interfacial reaction mechanisms and reaction kinetics in oxides. In the present
work, solid state reactions in different oxide systems, viz. BaCO -TiO , BaO-TiO , SrO-TiO ,3 2 2 2
CaO-TiO and MgO-TiO , are investigated.2 2
In the first two systems, BaCO -TiO and BaO-TiO , the solid state reaction of solid BaCO3 2 2 3
and BaO vapour with TiO substrates of different crystallographic structure (anatase and rutile)2
are studied in a thin film geometry. In particular, phase formation, phase sequence and orientation
of the reaction phases are analysed. The main goal of this part of the Ph.D. work was to study the
mechanism of BaTiO formation in vacuum and in air. The solid state reaction between BaCO3 3
and TiO raw materials is still one of the main industrial ways for BaTiO production. The BaTiO2 3 3
forming process usually occurs via an intermediate Ba TiO compound. There are many experi-2 4
mental works which describe the formation of BaTiO . At the beginning of the 1990s, Niepce and3
12Thomas have proposed a model based on spherical TiO particles surrounded by BaCO . For2 3
this arrangement, they have predicted that it is possible to prevent the formation of the Ba TiO2 4
phase by co