표제지
목차
Abstract 6
제1장 서론 16
제2장 이론적 배경 19
2.1. 스테인리스강의 부동태 19
2.1.1. 부동태 피막의 성장모델 19
2.1.2. 부동태 피막 손상 21
2.2. 스테인리스강의 부식 형태 27
2.2.1. 균일부식 27
2.2.2. 공식 29
2.2.3. 갈바닉 부식 33
2.2.4. 틈부식 36
2.2.5. 입계부식 36
2.2.6. 환경기인균열 40
2.3. 스테인리스강의 특성에 영향을 미치는 원소 45
2.3.1. 몰리브데넘 45
2.3.2. 니켈 45
2.3.3. 크롬 47
2.3.4. 질소 47
2.3.5. 탄소 48
2.3.6. 망간 49
2.3.7. 황 49
2.3.8. 타이타늄 50
2.4. 선박 연료유에 대한 배출가스 규제 52
2.5. 탈황장비의 종류 및 부식메커니즘 56
2.5.1. 건식 스크러버 56
2.5.2. 습식 스크러버 58
2.6. 탈황장치의 부식 원인 67
2.6.1. 황산 노점 부식 67
2.6.2. 염소이온의 영향 69
2.6.3. 퇴적물의 영향 71
2.7. 슈퍼오스테나이트 스테인리스강의 개발 73
제3장 시편 및 실험방법 76
3.1. 스테인리스강의 재료 및 환경 변수 76
3.2. 동전위 분극실험 79
3.3. 순환동전위 분극곡선 84
제4장 실험결과 및 고찰 87
4.1. 천연해수에서 동전위 분극특성 87
4.2. 천연해수에서 순환동전위 분극특성 110
4.3. 탈황장치모사용액에서 동전위 분극특성 139
4.4. 탈황장치모사용액에서 순환동전위 분극특성 158
제5장 결론 184
참고문헌 186
Chapter 2 15
Table 2.5.1. Washwater discharge criteria 61
Chapter 3 15
Table 3.1.1. Chemical composition of natural seawater 77
Table 3.1.2. Chemical composition of green death solution 78
Chapter 4 15
Table 4.1.1. Alpha(α) value calculation process after potentiodynamic polarization experiment with temperature for UNS S31603 and UNS N08367 in... 106
Table 4.2.1. Alpha(α) value calculation process after cyclic potentiodynamic polarization experiment with temperature for UNS S31603 and UNS... 135
Table 4.3.1. Alpha(α) value calculation process after electrochemical experiment with temperature for UNS S31603, UNS N08367 in modified green... 155
Table 4.4.1. Alpha(α) value calculation process after CPDP experiment with temperature for UNS S31603, UNS N08367 in modified green death solution 180
Chapter 2 8
Fig. 2.1.1. Potential distribution between metal and solution (m : metal, f : film, s : solution, mf : metal/film interface, fs : film/solution interface) 20
Fig. 2.1.2. The passivation film growth mechanism of place exchange model (a) Metal before film formation, (b) Oxygen adsorption, (c) Oxygen and... 22
Fig. 2.1.3. Passive film growth mechanism of point defect model (2) film formation, (5) The reaction that causes the disappearance of the... 23
Fig. 2.1.4. Passive film growth model by water adsorption and dehydrogenation (a) Dissolution and dehydrogenation of cations, (b) (a) Reaction continues,... 24
Fig. 2.2.1. Corrosion rate of stainless steel in sulfuric acid solution at 20℃ 28
Fig. 2.2.2. Sulfuric acid concentration and temperature for corrosion rate of 25 g/m²·d for 300 series stainless steel 30
Fig. 2.2.3. Corrosion rate of 300 series and 400 series stainless steels in boiled phosphoric acid 31
Fig. 2.2.4. Pits growth mechanism 32
Fig. 2.2.5. Galvanic series measured under marine environment 34
Fig. 2.2.6. Corrosion in Fe-stainless steel galvanic pairs 35
Fig. 2.2.7. Intergranular corrosion behavior of 304 stainless steel 38
Fig. 2.2.8. Intergranular carbide precipitation and chromium depletion region 39
Fig. 2.2.9. Schematic diagram of the stress-tensile curve when stress corrosion cracking occurs 41
Fig. 2.2.10. Stress corrosion cracking mechanism in aqueous solution containing chlorine ions 42
Fig. 2.3.1. Effect of nickel content on stress corrosion cracking of 18~20 Cr stainless steel wire in magnesium chloride solution at 154℃ 46
Fig. 2.4.1. Sulfur content regulation in flue gas by the International Maritime Organization 54
Fig. 2.5.1. Dry type scrubber system 57
Fig. 2.5.2. Open loop type scrubber system 59
Fig. 2.5.3. Closed loop type scrubber system 63
Fig. 2.5.4. Hybrid loop type scrubber system 66
Fig. 2.6.1. Effect of temperature on dew point corrosion by sulfuric acid and hydrochloric acid 68
Fig. 2.6.2. Corrosion process by chlorine 70
Fig. 2.6.3. Mechanism of corrosion by deposit 72
Chapter 3 9
Fig. 3.2.1. Potentiodynamic polarization experiment apparatus 80
Fig. 3.2.2. Electrochemical experiment equipment and monitoring display (FR/VSP, BioLogic Science instrument) 81
Fig. 3.2.3. 3D analysis microscope 82
Fig. 3.2.4. Scanning electron microscope (SEM) apparatus 83
Fig. 3.3.1. Cyclic potentiodynamic experiment polarization apparatus 86
Chapter 4 10
Fig. 4.1.1. Potentiodynamic polarization curves for UNS S31603 and UNS N08367 with temperature in seawater 88
Fig. 4.1.2. Comparison of corrosion current density by Tafel analysis after potentiodynamic polarization experiment for UNS S31603 and UNS... 92
Fig. 4.1.3. Comparison of pitting potential after potentiodynamic polarization experiment for UNS S31603 and UNS N08367 in sea water 94
Fig. 4.1.4. Appearance and corrosion area ratio after potentiodynamic polarization experiment with temperature for UNS S31603 and UNS N08367 in sea water 95
Fig. 4.1.5. Surface morphologies after potentiodynamic polarization experiment with temperature for UNS S31603 and UNS N08367 in sea water 97
Fig. 4.1.6. Maximum damage depth after potentiodynamic polarization experiment with temperature for UNS S31603 and UNS N08367 in sea water 100
Fig. 4.1.7. Depth histogram and surface roughness after potentiodynamic polarization experiment with temperature for UNS S31603 and UNS... 102
Fig. 4.1.8. Corrosion rate after potentiodynamic polarization experiment with temperature for UNS S31603 and UNS N08367 in sea water 103
Fig. 4.1.9. Alpha(α) value after potentiodynamic polarization experiment with temperature for UNS S31603 and UNS N08367 in sea water 107
Fig. 4.2.1. Example interpretation of cyclic potentiodynamic polarization curves for UNS N08367 in seawater(→←, Scan direction)[이미지참조] 111
Fig. 4.2.2. Cyclic potentiodynamic polarization curves for UNS S31603 and UNS N08367 with temperature in seawater (Open symbol : Forward... 112
Fig. 4.2.3. Comparison of corrosion current density by Tafel analysis after cyclic potentiodynamic polarization experiment for UNS S31603 and UNS... 115
Fig. 4.2.4. Comparison of pitting potential after cyclic potentiodynamic polarization experiment for UNS S31603 and UNS N08367 in sea water 116
Fig. 4.2.5. Repassivation and anodic to cathodic transition potential at reverse scan after cyclic potentiodynamic polarization experiment for UNS N08367 in... 118
Fig. 4.2.6. Enclosed area in hysteresis loop at reverse scan after cyclic potentiodynamic polarization experiment for UNS N08367 in sea water 121
Fig. 4.2.7. Appearance after cyclic potentiodynamic polarization experiment with temperature for UNS S31603 and UNS N08367 in sea water 124
Fig. 4.2.8. Surface morphologies after cyclic potentiodynamic polarization experiment with temperature for UNS S31603 and UNS N08367 in... 126
Fig. 4.2.9. Maximum damage depth after cyclic potentiodynamic polarization experiment with temperature for UNS S31603 and UNS N08367 in... 128
Fig. 4.2.10. Depth histogram and surface roughness after cyclic potentiodynamic polarization experiment with temperature for UNS S31603 and UNS... 131
Fig. 4.2.11. Corrosion rate after cycic potentiodynamic polarization experiment with temperature for UNS S31603 and UNS N08367 in sea water 133
Fig. 4.2.12. Alpha(α) value after cyclic potentiodynamic polarization experiment with temperature for UNS S31603 and UNS N08367 in sea water 136
Fig. 4.3.1. Potentiodynamic curves after electrochemical experiment for UNS S31603 and UNS N08367 in modified green death solution 140
Fig. 4.3.2. Results of Tafel analysis after electrochemical experiment for UNS S31603 and UNS N08367 in modified green death solution 142
Fig. 4.3.3. Schematic diagrams of the bipolar model and the passive film mechanism formed on stainless in green death solution 143
Fig. 4.3.4. Schematic diagrams of the selective dissolution and re-deposition mechanism on stainless steel in green death solution 145
Fig. 4.3.5. Appearance and corrosion area ratio after electrochemical experiment with temperature for UNS S31603 and UNS N08367 in modified green... 147
Fig. 4.3.6. Surface morphologies after electrochemical experiment with temperature for UNS S31603 and UNS N08367 in modified green death solution 149
Fig. 4.3.7. Surface damage depth after electrochemical experiment with temperature for UNS S31603 and UNS N08367 in modified green death solution 151
Fig. 4.3.8. Corrosion rate(mm/yr) after electrochemical experiment with temperature for UNS S31603 and UNS N08367 in modified green death solution 153
Fig. 4.3.9. Alpha(α) value after electrochemical experiment with temperature for UNS S31603, UNS N08367 in modified green death solution 156
Fig. 4.4.1. Schematic diagram and corrosion mechanism of CPDP curves for stainless steel with Mo and Cr 159
Fig. 4.4.2. Cyclic potentiodynamic polarization curves for UNS S31603 and UNS N08367 in modified green death solution (Open symbol : Forward... 162
Fig. 4.4.3. Comparison of corrosion current density by Tafel analysis after CPDP experiment for UNS S31603 and UNS N08367 in modified green... 164
Fig. 4.4.4. Difference between reverse scan, anodic to cathodic transition potential and corrosion potential after CPDP experiment for UNS S31603 and... 166
Fig. 4.4.5. Comparison of flade potential and critical current density after CPDP experiment with temperature for UNS S31603 and UNS N08367 in... 168
Fig. 4.4.6. Corrosion area ratio after CPDP experiment with temperature for UNS S31603 and UNS N08367 in modified green death solution 170
Fig. 4.4.7. Surface morphologies after CPDP experiment with temperature for UNS S31603 and UNS N08367 in modified green death solution 171
Fig. 4.4.8. Maximum surface damage depth after CPDP experiment with temperature for UNS S31603 and UNS N08367 in modified green... 174
Fig. 4.4.9. 3D anlysis and depth histogram of surface roughness after CPDP experiment with temperature for UNS S31603 and UNS N08367 in... 176
Fig. 4.4.10. Corrosion rate after CPDP experiment with temperature for UNS S31603 and UNS N08367 in modified green death solution 178
Fig. 4.4.11. Alpha(α) value after CPDP experiment with temperature for UNS S31603, UNS N08367 in modified green death solution 181