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Table of content
List of abbreviations ... 5 Introduction ... 7 I. Literature survey ... 9 1. Development of biomaterials ... 9 2. Biomaterials market ... 122.1 Demand for the joint replacements ... 12
3. Hip joint anatomy ... 14
3.1 Bone structure and function ... 15
3.2 Cartilage structure and function ... 19
3.3 Reasons of hip joint damage ... 21
4. Hip joint implant ... 22
4.1 Development of hip joint implant ... 25
5. Materials used for hip joint implant ... 28
5.1 Metals and alloys ... 31
5.1.1 Titanium alloys... 34
5.2 Polymers ... 37
5.3 Ceramics ... 39
6. Revision surgeries of hip joint implant ... 40
7. Directions in surface modifications of titanium alloys ... 42
7.1 Micro-arc oxidation ... 45
7.1.1 MAO coatings growth mechanism and discharge classification ... 46
7.1.2 Application of MAO process for metallic biomaterials ... 49
II. Aim of the study ... 53
III. Material and methods ... 54
1. Substrate - Ti6Al7Nb alloy ... 54
2. Preparation of Ti6Al7Nb samples for MAO processing ... 54
3. Coatings deposition ... 54
4. Characterization of the coatings ... 56
4.1 Microstructure, morphology and chemical composition of the coatings ... 56
4.1.1 Scanning electron microscopy (SEM) ... 56
4.1.2 X-ray diffractometry (XRD) ... 57
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4.1.4 Energy dispersive X-ray spectroscopy (EDXS) ... 58
4.2 Nanoindentation test ... 59
4.3 Scratch test ... 59
4.4 Roughness measured by profilometer ... 59
4.5 Contact angle measurement ... 59
4.6 FIB-SEM tomography ... 60 4.7 Bioactivity ... 60 4.8 Cell cultures ... 61 4.8.1 Fluorescence microscopy ... 61 4.8.2 Confocal microscopy ... 62 4.8.3 Proliferation assay ... 62
4.8.4 Scanning electron microscopy (SEM) ... 62
4.8.5 FIB-SEM tomography ... 63
IV. Results and discussion ... 64
1. Study of MAO reaction time ... 64
1.1 Microstructure, chemical and phase composition ... 64
1.2 Roughness and wettability ... 69
1.3 In vitro cell culture ... 70
2. Study of the electrolyte composition in MAO process ... 75
2.1 Microstructure, chemical and phase composition ... 75
2.2 Thickness and roughness ... 81
2.3 Transmission electron microscopy ... 83
2.4 Nanoindentation and scratch tests ... 88
2.5 FIB-SEM tomography of the coating ... 90
2.6 Bioactivity ... 92
2.7 In vitro cell culture ... 95
2.8 FIB-SEM tomography of the cell-coating interface ... 101
V. Summary and conclusions ... 103
