표제지
목차
Abstract 7
제I장. 서론 9
제II장. 이론적 배경 12
1. 지르코니아(ZrO₂)의 특성 12
2. 마이크로웨이브 소결(microwave sintering) 16
III. 실험 방법 23
1. 시편준비 23
2. 시편분석 23
1) 소결 시간에 따른 밀도 변화 23
2) 시편 두께에 따른 밀도 변화 24
3) 밀도측정 24
4) 미세구조 관찰 25
IV. 실험결과 26
1. 소결 시간에 따른 밀도 변화 26
2. 시편 두께 및 승온속도에 따른 밀도 변화 31
V. 결론 37
References 38
감사의 글 41
Table 1. Composition of Y-TZP everest ZS Blank. 23
Table 2. Sintering schedule by conventional electric furnace. 23
Table 3. Sintering schedule by microwave furnace. 24
Table 4. Density change by conventional sintering time. 26
Table 5. Density change by microwave sintering time 26
Table 6. Density changes by thickness in conventional electric furnace. 31
Table 7. Density change by thickness in microwave furnace. 31
Table 8. Retrial sintering schedule in Microwave Furnace. 33
Table 9. Density changes by the temperature increasing speed of a) 20℃ /min, b)30℃ /min, c)40℃/min. 34
Fig. 1. Represention of stress-induced transformation toughening in Zirconia. 13
Fig. 2. Polymorphic phase transformations of zirconia. 14
Fig. 3. Heating pattern in a) Conventional and b)Microwave furnce. 16
Fig. 4. Interaction of microwave with materials. 18
Fig. 5. Schematic representation of different mechanisms of polarization. 19
Fig. 6. Density changes of zirconia with sintering time in conventional electric furnace. 27
Fig. 7. Density changes of zirconia with sintering time in microwave furnace. 27
Fig. 8. Density change temperature graph by microwave and conventional sintering time 28
Fig. 9. SEM micrographs of sintered zirconia in conventional furnace at a) 1500℃ and b) 1550℃for 1 hour 30
Fig. 10. SEM micrographs of sintered zirconia in Microwave furnace at a) 1450℃ and b) 1500℃ for 5 minutes. 30
Fig. 11. Density changes of zirconia with specimen thickness. 32
Fig. 12. Surface images of microwave sintered specimens by different heating rates (20~400℃). a) 30℃/min and b) 50℃/min. 33
Fig. 13. Density changes of Microwave sintered zirconia with specimen thickness. 35
Fig. 14. SEM micrographs of the fractured surface of conventional sintered zirconia at a) 1500℃ and b) 1550℃. 36
Fig. 15. SEM micrographs of the fractured surface of microwave sintered zirconia at a) 1450℃ and b) 1500℃. 36