ZnO-SnO2-SiO2 3원계 시스템의 상태도 실험과 열역학 모델링

학위논문 (석사) -- 서울대학교 대학원 : 공과대학 재료공학부(하이브리드 재료), 2020. 8. 정인호.The development of an accurate thermodynamic database to calculate the thermodynamic properties and phase equilibria in complex systems plays an important role in the development of many ceramic and metallurgical processes. Thermodynamic database is developed by the comprehensive critical evaluation and optimization of all the thermodynamic property and phase diagram data. As part of a large thermodynamic database development for glassmaking and metallurgical applications, the entire ZnO-SnO2-SiO2 system was critically evaluated and optimized. Due to the lack of phase diagram experiment data in the ZnO-SnO2, SnO2-SiO2, and the ternary ZnO-SnO2-SiO2 system, the phase equilibria in the binary and ternary systems were determined using the classical quenching experiments and differential thermal analysis (DTA) followed by X-ray diffraction (XRD) analysis and electron probe micro-analysis (EPMA). Sealed platinum capsules were employed for preventing the evaporation of ZnO and SnO2 in the experiments. In the course of the optimization, the melting temperature of SnO2 was re-evaluated. The phase diagrams of ZnO-SnO2, SnO2-SiO2, and ZnO-SnO2-SiO2 systems were constructed for the first time. By using the construct thermodynamic database containing the Gibbs energy functions of all phases in the ternary system, phase equilibria and the thermodynamic properties within the ternary system could be accurately calculated. All the thermodynamic calculations and optimization in the present study were carried out using the FactSageTM thermochemical software.Chapter 1. Introduction 1 1.1. Research Objective 1 1.2. Organization 2 Chapter 2. Thermodynamic Optimization and the CALculation of PHAse Diagrams (CALPHAD) Approach 4 2.1. Thermodynamic Optimization 4 2.2. Thermodynamic Models 7 2.2.1. Stoichiometric Compounds 7 2.2.2. Liquid Solution 9 2.2.3. Metallic and Gas Phases 11 Chapter 3. Key Phase Diagram Experiments and the Thermodynamic Optimizations of Binary ZnO-SnO2, ZnO-SiO2, and SnO2-SiO2 Systems 18 3.1. Introduction 19 3.2. Phase Diagram Experiment 19 3.2.1. Starting Materials 19 3.2.2. Differential Thermal Analysis 20 3.2.3. Quenching Experiments 21 3.2.4. Phase Characterizations 22 3.3. The ZnO-SiO2 System 22 3.4. Study of the ZnO-SnO2 System 23 3.4.1. Literature Review 23 3.4.2. Key Phase Diagram Experiments 24 3.4.3. Thermodynamic Optimization 26 3.5 Study of the SnO2-SiO2 System 27 3.5.1. Literature Review 27 3.5.2. Key Phase Diagram Experiments 28 3.5.3. Thermodynamic Optimization 30 Chapter 4. A Coupled Phsae Diagram Experiment and Thermodynamic Optimization of the ZnO-SnO2-SiO2 System 45 4.1. Introduction 45 4.2. Literature Review 45 4.3. Phase Diagram Experiments 45 4.3.1. Materials Preparation 46 4.3.2. Differential Thermal Analysis 47 4.3.3. Quenching Experiments 48 4.3.3.1. Phase Diagram at Sub-Solidus Temperature (1200oC) 48 4.3.3.2. Ternary Eutectic Compositions 49 4.3.3.3. Isothermal Phase Diagram at 1600oC 50 4.3.3.4. Quenching Experiments Above 1650oC 51 4.3.3.5. Others 52 4.5. Thermodynamic Modeling 52 Chapter 5. Conclusion 73 Appendix. Re-optimization of the Sn-O Phase Diagram and the Preliminary Studies on the Binary Phase Diagrams Containing SnO2 75 Appendix-1. Introduction 75 Appendix-2. Redefinition of the Melting Point of SnO2 75 Appendix-2.1. Literature Review 76 Appendix-2.2. The SnO2-Al2O3 System 77 Appendix-2.2.1. Experimental Method 77 Appendix-2.2.2. Results and Discussion 78 Appendix-2.2.3. Re-deterimination of the Melting Temperature of SnO2 78 Appendix-2.2.4. Thermodynamic Modeling of the SnO2-Al¬2O3 System 80 Appendix-3. Re-optimization of the Sn-O Phase Diagram 81 Appendix-4. Binary Systems Containing SnO2 82 Appendix-4.1. CaO-SnO2 System 82 Appendix-4.2. MgO-SnO2 System 83 Appendix-4.3. CoO-SnO2 System 84 Appendix-4.4. MnO-SnO2 System 85 Appendix-4.5. ZrO2-SnO2 System 85 Bibliography 101Maste