Synthesis, Characterization and Tribological Properties of Silicon Carbide Derived Carbon Layer
- 주제(키워드) carbon , tribology , tribology
- 발행기관 고려대학교 대학원
- 지도교수 임대순
- 발행년도 2014
- 학위수여년월 2014. 8
- 학위구분 박사
- 학과 일반대학원 신소재공학과
- 원문페이지 142 p
- 실제URI http://www.dcollection.net/handler/korea/000000052646
- 본문언어 영어
- 제출원본 000045808717
초록/요약
In the first part, Nanostructured carbide-derived carbons (CDCs) were synthesized from hexagonal SiC (α-SiC) and cubic SiC (β-SiC) powders via chlorination at temperatures between 900 and 1200 °C. The content of the sp2- and sp3-bonded carbon phases and their crystallinity were analyzed by Raman spectroscopy. The nanocrystalline phases of the synthesized CDCs were observed and characterized by transmission electron microscopy and electron energy-loss spectroscopy. Mechanical properties were measured with tribological tests. The morphology of CDCs showed interesting features that varied with the starting SiC powder. Diamond nanocrystals were more frequently observed in α-SiC-derived carbons than in β-SiC-derived carbons, and the rate of graphitization was affected by the SiC polytype, synthesis temperature and hydrogen content. A possible mechanism responsible for the observed results was also investigated. In the second part, carbide derived carbon layers were synthesized on silicon carbide with two different halogen reactants of chlorine gas and vaporized chloroform via chlorination time and temperature. The influence of the chlorination as a reactant on the carbon structure was analyzed with X-ray diffraction, Raman spectroscopy and X-ray photoelectron spectroscopy. Pore morphology and specific surface area was resolved using surface area and porosity analyzer. Tribological properties were measured with pin-on disk type tribometer. Chloroform treated CDCs overcome the present limitations and showed enhancement on properties. The surface roughness was greatly increased due to the chemical bond between CDC and decomposed chloroform. Consequently decrease of specific surface area and more graphitization was also observed, and the mechanical properties related on tribological properties were greatly improved.
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ABSTRACT i
LIST OF FIGURES vii
LIST OF TABLES xi
GLOSSARY OF ABBREVIATION xii
Chapter 1. Introduction 1
Chapter 2. Theoretical Background 7
2.1. Carbon 7
2.1.1. The Allotropes of Carbon 7
2.1.2. Graphite 13
2.1.3. Graphene 17
2.1.4. Diamond 19
2.2. Silicon Carbide 23
2.2.1. Historic Overview 23
2.2.2. Polytypes of SiC 25
2.2.3. Properties and Applications of SiC 28
2.3. Carbide Derived Carbon (CDC) 30
2.3.1. Historic Overview 30
2.3.2. Kinetics of Synthesis 31
2.2.3. Microstructures in CDC 38
2.2.4. Tribological Properties 44
Chapter 3. Experimental Procedure 48
3.1. Preparation of the Substrate Materials 48
3.1.1. Substrates for α- and β-SiCDCs 48
3.1.2. Substrates for Chlorine and Chloroform Treated CDCs 49
3-2. Synthesis of CDC 52
3.2.1. CDCs Derived from α- and β-SiC 52
3.2.2. CDCs Using Chlorine and Chloroform as a Reactant 56
3-3. Characterizations 60
3.3.1. Structural and Surface Morphology Analysis 60
3.3.2. Microstructural Analysis 60
3.3.3. Tribological Properties 67
Chapter 4. Results and Discussion 69
4.1. Effect of the Substrate Polytypes 69
4.1.1. Effect of Reaction Temperature 69
4.1.2. Effect of Hydrogen Concentration 79
4.1.3. Tribological Properties 86
4.1.4. Structural Analysis 88
4.2. Effect of Carbon Source in Chlorination Reactant 94
4.2.1. Thermal Decomposition of Chloroform 94
4.2.2. Microstructural Analysis 95
4.2.3. Tribological Properties 108
Chapter 5. Conclusions 114
References 116
Acknowledgment 127
