[표제지 등]

제출문

요약문

SUMMARY

List of Table

List of Figure

List of Figures in Appendix

칼라

목차

제1장 서론 27

제2장 국내외 기술 개발 현황 29

제3장 상대국과의 공동연구 역할분담체계 33

제4장 공동연구기관 및 연구책임자의 연구수행능력 34

제5장 공동연구개발수행 내용 및 결과 35

1절 연구의 배경 35

2절 이론적 배경 및 문헌고찰 39

1. 플라즈마 질화기구 39

가. 질화층의 특성 및 경화이론 43

2. CVD의 정의와 특징 48

3. Plasma Assisted CVD의 특징 49

4. 기상내 이동현상론 52

5. 플라즈마(Plasma) 58

6. 분자 운동 62

가. 평균 자유 경로와 충돌단면 62

나. 플라즈마내의 자유전자의 운동에너지 64

다. 플라즈마 쉬스(Sheath) 68

7. 박막의 밀착력 73

가. 밀착력 측정법 77

8. 전기화학적 부식시험법 82

가. 부동태화 금속에 대한 anode 분극곡선의 측정 82

(1) test approach 83

(2) potentiostat 84

(3) 기준전극 84

(4) counter 전극 85

(5) 분극 scan rate 85

9. 마모 86

가. 기계공학적 거시마찰기구 86

(1) 코팅층경도의 영향 86

(2) 코팅층 두께와 표면 거칠기의 영향 89

(3) 접촉계면간의 debris의 영향 89

나. 기계공학적 미세마찰기구 91

다. 코팅된 표면에서의 기계적 마찰기구 91

(1) 경질코팅층상의 미세박막형성 91

(2) 연질코팅층의 산화 93

라. 물질전이 기구 93

3절 실험장치 및 방법 94

1. Plasma nitriding 및 MO-PACVD 장치 94

2. 시편준비 96

3. 금속유기화합물 전구체 96

4. 실험방법 96

가. 플라즈마 질화 96

나. Ti(NCO)층 제조 99

다. nitrided+Ti(NCO)층 제조 100

라. 물성평가 101

4절 실험결과 및 고찰 103

1. 플라즈마 질화 103

2. Ti(NCO)화합물층 제조 116

가. precursor vol.%의 영향 116

나. 가스 조성비 변화의 영향 116

다. 기판온도의 영향 128

라. 코팅층 대 시간과의 관계 128

마. 전원 공급장치의 영향 133

3. nitrided+Ti(NCO) 복합층 제조 133

4. 내마모성 평가 140

5. 내식성 평가 146

6. 밀착력 측정 150

7. 현장적용 시험 152

8. 유체거동의 컴퓨터 시뮬레이션[원문불량;p.130] 152

가. Method of solution 158

나. 계산결과 159

부록 : 국제공동 연구기관인 폴란드 Warsaw University of Technology 연구결과(Reports on the nitriding and oxycarbonitriding of titanium and its alloys) 169

1. Introduction 170

2. Experimental Procedure 170

3. Results and discussion[원문불량;p.149] 172

4. Conclusions 182

References 186

제6장 공동 연구개발 목표 달성도 및 대외기여도 187

제7장 공동 연구개발 결과의 활용계획 188

제8장 참고문헌 189

[title page etc.]

SUMMARY

Contents

1. Introduction 27

2. Current status of technical development in domestic and foreign countries 29

3. Co-operative work plan 33

4. Research capabilities of counterpart 34

5. Co-operative work and results 35

5-1. Background of research 35

5-2. Theory and literature survey 39

5-2-1. Mechanism of plasma nitriding 39

5-2-1-1. Characteristics of nitrided layers and theory of hardening 43

5-2-2. Characteristics of CVD 48

5-2-3. Characteristics of Plasma Assisted CVD 49

5-2-4. Transport phenomena in gaseous phases 52

5-2-5. Plasma 58

5-2-6. Molecular dynamics 62

5-2-6-1. Mean free path and collision cross section 62

5-2-6-2. Kinetic energy of free electrons in plasma 64

5-2-6-3. Plasma sheath 68

5-2-7. Adhesion of thin films 73

5-2-7-1. Determination of adhesion 77

5-2-8. Electrochemical corrosion tests 82

5-2-8-1. Determination of anodic polarization curve 82

5-2-8-1-1. Test approach 83

5-2-8-1-2. Potentiostat 84

5-2-8-1-3. Standard electrode 84

5-2-8-1-4. Counter electrode 85

5-2-8-1-5. Polarization scan rate 85

5-2-9. Wear 86

5-2-9-1. Mechanism of macroscopic wear 86

5-2-9-1-1. Effect of coated layer hardness 86

5-2-9-1-2. Effects of layer thickness and surface roughness 89

5-2-9-1-3. Effect of interface debris 89

5-2-9-2. Microscopic wear 91

5-2-9-3. Wear at coated surface 91

5-2-9-3-1. Thin film formation of hard coated layer 91

5-2-9-3-2. Oxidation of soft coated layer 93

5-2-9-4. Mechanism of material transfer 93

5-3. Experimental methods and apparatus 94

5-3-1. Plasma nitriding and MO-PACVD apparatus 94

5-3-2. Sample preparation 96

5-3-3. Metallo-organic precursor 96

5-3-4. Experimental methods 96

5-3-4-1. Plasma nitriding 96

5-3-4-2. Synthesis of Ti(NCO) layer 99

5-3-4-3. Synthesis of nitrided+Ti(NCO) 100

5-3-4-4. Characterization 101

5-4. Experimental results 103

5-4-1. Plasma nitriding 103

5-4-2. Synthesis of Ti(NCO) layer 116

5-4-2-1. Effect of precursor vol.% 116

5-4-2-2. Effect of gas composition 116

5-4-2-3. Effect of substrate temperature 128

5-4-2-4. Coated layer vs. time 128

5-4-2-5. Effect of power supply 133

5-4-3. Synthesis of nitrided+Ti(NCO) composite layer 133

5-4-4. Wear resistance 140

5-4-5. Corrosion resistance 146

5-4-6. Adhesion 150

5-4-7. Trial test 152

5-4-8. Computer simulation on fluid flow[원문불량;p.130] 152

5-4-8-1. Method of solution 158

5-4-8-2. Computed results 159

Appendix 169

1. Introduction 170

2. Experimental Procedure 170

3. Results and discussion[원문불량;p.149] 172

4. Conclusions 182

References 186

6. Achievement and scientific benefits 187

7. Application plans 188

8. References 189

Table 1. Mechanical methods to determine adhesion 75

Table 2. Non-mechanical methods to determine adhesion 75

Table 3. Chemical composition of tested specimens 97

Fig. 1. Mechanism of plasma nitriding. 41

Fig. 2. General structure of plasma nitrided layer. 44

Fig. 3. Fe-N phase diagram. 46

Fig. 4. Mean free path. 54

Fig. 5. Parameter between molecules. 57

Fig. 6. Collision cross sections for electrons in Ar gas. 63

Fig. 7. Cross section for the reaction of O+ ions with N₂ to produce NO++N(이미지참조) 65

Fig. 8. Electron (Te) and gas temperature (Tg) in an air arc as a function of pressure.(이미지참조) 67

Fig. 9. Schematic illustration of sheaths that form between a plasma discharge and the surrounding apparatus walls for systems having (A) a large anode and (B) a small anode. 70

Fig. 10. Schematic representation of the positive space-charge sheath that develop over a cathode. 72

Fig. 11. Schematic representation of a charge exchange reactions in the cathode fall region of a glow discharge. 74

Fig. 12. The five regions in which separation can take place. 76

Fig. 13. Benjamin and Weaver's Mode 79

Fig. 14. The scratch adhesion test represented as the sum of three contribution : as indentation term, an internal stress term and a friction term. 81

Fig. 15. Macromechanical contact condition for different mechanism which influence friction. 87

Fig. 16. Macromechanical contact condition for different wear mechanism. 88

Fig. 17. A hard slider on a soft counterface results in ploughing(a), which can be inhibited by using a hard coating on the substrate, as shown in (b), a soft microfilm on top of the hard coating results in decreased friction, as in (c). 90

Fig. 18. The velocity accomodation in a coated sliding contact may take place in (1) the counterface... 92

Fig. 19. Schematic diagram of the universal apparatus (1. power supply 2. heater 3. substrate holder 4. evaporator 5. MFC 6. dosing device 7. vent 8. pressure sensor 9. rotary pump 10. diffusion pump) 95

Fig. 20. Molecular structure of Ti(OC₃H7(이미지참조))₄ 98

Fig. 21. Effect of H₂／N₂ ratio on layer thickness(SKD11, T＝450℃, P＝4.9mabar, t＝2hr) 104

Fig. 22. Effect of H₂／N₂ ratio on hardness(SKD11, T＝450℃, P＝4.9mbar, t＝2hr) 105

Fig. 23. Effect of temperature on layer thickness(SKD11, H₂／N₂＝95%:5%, P＝4.9mbar, t＝4hr) 106

Fig. 24. SEM micrographs of samples plasma nitrided at various temperatures. 108

Fig. 25. Effect of pressure on layer thickness.(SKD11, H₂／N₂＝95%:5%, T＝450℃, t＝4hr) 109

Fig. 26. Effect of treating time on layer thickness.(SKD11, H₂／N₂＝95%:5%, T＝450℃, P＝4.9mbar) 110

Fig. 27. Effect of heat treating on diffusion layer thickness.(SKD11, H₂／N₂＝95%:5%, T＝450℃, P＝4.9mbar) 111

Fig. 28. Effect of heat treating time on diffusion layer thickness.(SKD61, H₂／N₂＝95%:5%, T＝450℃, P＝4.9mbar) 112

Fig. 29. Effect of heat treating on diffusion layer thickness.(SKH9, H₂／N₂＝95%:5%, T＝450℃, P＝4.9mbar) 113

Fig. 30. Effect of heat treating on hardness after plasma nitriding(SKD11, H₂:N₂＝95%:5%, T＝450℃, P＝4.9mbar, t＝2hr) 114

Fig. 31. Variation of hardness of heat treated samples after plasma nitriding.(SKD11, H₂:N₂＝95%:5%, T＝450℃, P＝4.9mbar) 115

Fig. 32. Effect of heat treating on layer thickness(SKD 11, H₂／N₂＝95%:5%, T＝450℃, P＝4.9mbar) 117

Fig. 33. Effect of H₂／N₂ ratio on hardness of Ti(NCO) layer formed on SKD11, SKD61 and SKH9 steels (T＝500℃) 118

Fig. 34. Auger profile at the surface of Ti(NCO) layer.(SKD11, H₂／N₂ ratio＝1:1, T＝500℃) 120

Fig. 35. Auger depth profile of Ti(NCO) layer.(SKD11, H₂／N₂ ratio＝1:1, T＝500℃) 121

Fig. 36. Auger depth profile of Ti(NCO) layer.(SKD11, H₂／N₂ ratio＝7:3, T＝500℃) 122

Fig. 37. Auger depth profile of Ti(NCO) layer.(SKD11, H₂／N₂ ratio＝3:7, T＝500℃) 123

Fig. 38. Auger profile at the final point of depth.(SKD11, H₂／N₂ ratio＝3:7, T＝500℃) 124

Fig. 39. Surface topography of Ti(NCO) layers(T＝500℃) : (a) H₂／N₂＝7:3, (b) H₂／N₂＝1:1, (c) H₂／N₂＝3:7 126

Fig. 40. Effect of temperature on hardness of Ti(NCO) layer formed on SKD11, SKD61 and SKH9 steels(H₂／N₂＝1:1). 129

Fig. 41. Surface topography of Ti(NCO) layers(H₂／N₂＝1:1) : (a) T＝450℃ (b) T＝500℃ (c) T＝550℃ 130

Fig. 42. Variation of the radiation intensity of selected spectral lines as a function of the cathode temperature. 131

Fig. 43. Coating thickness vs. time. 132

Fig. 44. Effect of frequency on hardness of Ti(NCO) layers. 134

Fig. 45. Effect of duty on hardness of Ti(NCO) layers. 135

Fig. 46. Effect of plasma power on hardness of Ti(NCO) layers. 136

Fig. 47. Surface topography of Ti(NCO) layers obtained at various H₂／N₂ ratios using pulsed power. 137

Fig. 48. Surface topography of Ti(NCO) layers obtained at various temperatures using pulsed power. 138

Fig. 49. X-ray diffractograms of (a) the nitrided layer, (b) Ti(NCO) layer without nitriding and (c) nitrided+Ti(NCO) layer on SKD11 steel. 139

Fig. 50. SEM micrographs of (a) Ti(NCO) layer and (b) nitrided+Ti(NCO) layer on SKD11 steel. 141

Fig. 51. Surface roughness of (a) Ti(NCO) layer and (b) nitrided+Ti(NCO) layer. 142

Fig. 52. EPMA analysis of the nitrided+Ti(NCO) layer produced on SKD11 steel. 143

Fig. 53. Results of measurement(measurment) of friction coefficient of (a) nitrided layer (b) nitrided+Ti(NCO) layer obtained on SKD11 steel. 144

Fig. 54. Linear wear occurring on SKD11 steel Ti(NCO) layer and nitrided+Ti(NCO) layer at 400Mpa load. 145

Fig. 55. Potentiodynamic curves of Ti(NCO) coated samples obtained with various H₂／N₂ ratios(T＝500℃). 147

Fig. 56. Potentiodynamic curves of Ti(NCO) coated samples obtained at various temperatures (H₂／N₂＝1:1). 148

Fig. 57. Potentiodynamic curves of the base material, nitrided layer, Ti(NCO) layer and nitrided+Ti(NCO) layer obtained on SKD11 steel. 149

Fig. 58. Optical micrographs of the scratch tracks (a) Ti(NCO) layer (b) nitrided+Ti(NCO) layer. 151

Fig. 59. Land wear of end mill vs. milling time. 153

Fig. 60. Top view of end mills after milling(left:nitrided+Ti(NCO) coated, right:uncoated) 154

Fig. 61. Schematic diagram of the reaction chamber and boundary conditions[원문불량;p.130] 156

Fig. 62. Predicted streamlines for the chamber without inlet tube. 160

Fig. 63. Predicted temperature distributions for the chamber without inlet tube. 161

Fig. 64. Predicted streamlines for the chamber with inlet tube. 162

Fig. 65. Predicted temperature profile for the chamber with inlet tube. 163

Fig. 66. Predicted streamlines for the chamber with inlet tube and funnel 164

Fig. 67. Predicted temperature distributions for the chamber with inlet tube and funnel. 165

Fig. 68. Predicted streamlines for the chamber with inlet tube and shower head 166

Fig. 69. Predicted temperature distributions for the chamber with inlet tube and shower head. 167

Fig. 1. Microstructures of cross sections of the surface layers produced on the OT4-0 alloy by isothermal plasma nitriding (a), cyclic plasma nitriding (b), oxycarbonitriding (c) and cyclic oxycarbonitriding (d). (×500) 173

Fig. 2. Anodic polarization curves of the corrosion resistance of layers produced in isothermal plasma nitriding, cyclic plasma nitriding, isothermal oxycarbonitriding, cyclic oxycarbonitriding and base metal in 1.8 M H₂SO₄ solution. 174

Fig. 3. Topography of the surface layers produced on the OT4-0 alloy by isothermal plasma nitriding (a), cyclic plasma nitriding (b), oxycarbonitriding (c) and cyclic oxycarbonitriding. (1cm＝10㎛) 176

Fig. 4. Anodic polarization curves of the corrosion resistance of layers produced in various methods and base metal measured in the 0.5 M NaCl. 177

Fig. 5. Chemical composition of the nitrided (a), carbonitrided (b) layers formed on the OT4-0 alloy. 178

Fig. 6. Linear wear of the nitrided, carbonitrided, oxycarbonitrided layers and base metal under loads 100 MPa (a) and 200 MPa (b). 179

Fig. 7. Anodic polarization curves of layers produced by isothermal and cyclic plasma nitriding before and after the sterilization process in a special solution... 180

Fig. 8. Distribution of titanium, carbon, nitrogen and oxygen in the surface zone of nitrided (a) and oxycarbonitrided (b) layers. 183

Fig. 9. Fibroblast growth on the nitrided and oxycarbonitrided layers. 184

Fig. 10. Polarization curves of nitrided layers on the OT4-0 alloy produced at different parameters : a) T＝730℃, t＝1h, b) T＝1000℃, t＝4h compared with (c) OT4-0 titanium alloy. 185