This document is downloaded from DR‑NTU (https://dr.ntu.edu.sg) Nanyang Technological University, Singapore. Fabrication and characterization of graphene and carbon nanotube reinforced bioceramic nanocomposites Hu, Huanlong 2019 Hu, H. (2019). Fabrication and characterization of graphene and carbon nanotube reinforced bioceramic nanocomposites. Doctoral thesis, Nanyang Technological University, Singapore. https://hdl.handle.net/10356/136922 https://doi.org/10.32657/10356/136922 This work is licensed under a Creative Commons Attribution‑NonCommercial 4.0 International License (CC BY‑NC 4.0). Downloaded on 04 Oct 2021 06:24:45 SGT FABRICATION AND CHARACTERIZATION OF GRAPHENE AND CARBON NANOTUBE REINFORCED BIOCERAMIC NANOCOMPOSITES HU HUANLONG SCHOOL OF MECHANICAL AND AEROSPACE ENGINEERING NANYANG TECHNOLOGICAL UNIVERSITY 2019 FABRICATION AND CHARACTERIZATION OF GRAPHENE AND CARBON NANOTUBE REINFORCED BIOCERAMIC NANOCOMPOSITES Hu Huanlong School of Mechanical and Aerospace Engineering A thesis submitted to the Nanyang Technological University in partial fulfillment of the requirement for the degree of Doctor of Philosophy 2019 Acknowledgements Acknowledgments First of all, I would like to express my sincere gratitude to my supervisor, Prof. Khor Khiam Aik, and my co-supervisor, Assoc. Prof. Li Hua for their continuum guidance and encouragement during the past years. Thank you Prof. Khor for your insightful comments and advice that the meetings and discussions with you always give me a lot of thinking and inspirations. You not only help me touch deeper knowledge in the present research area, but also taught me life truths that will be beneficial for my life. Thank you Prof. Li for keeping me on the track. Besides my supervisors, I would like to thank my Thesis Advisory Committee members, Assoc. Prof. Dong Zhili and Assoc. Prof. Su Peichen for their valuable comments and encouragements. I also appreciate the friendship and technical help from my seniors Dr. Li Ruitao, Dr. Li Zhong, Dr. Xu Jinling, and Dr. Yu Ligen. The technicians in MAE Materials Labs are also appreciated. Thank you Mr. Leong Kwok Phui, Ms. Yong Mei Yoke, Ms. Sandy Yeong Peng Neo and Mr. Thomas Lew for the technical support. Last but not least, I would like to thank my parents for their selfless love and support in the past 29 years. Thank you for raising me up and encouraging me to pursue my dreams. i Table of contents Table of contents ACKNOWLEDGMENTS .......................................................................................................... I TABLE OF CONTENTS ........................................................................................................... II ABSTRACT……..................................................................................................................... V ABBREVIATIONS .............................................................................................................. VIII FIGURE CAPTIONS.............................................................................................................. IX TABLE CAPTIONS ............................................................................................................. XVI CHAPTER 1 INTRODUCTION .............................................................................................. 1 1.1 BACKGROUND .......................................................................................................................................1 1.2 OBJECTIVES AND SCOPE ..........................................................................................................................3 CHAPTER 2 LITERATURE REVIEW ....................................................................................... 6 2.1 BONE AND BIOCERAMICS ........................................................................................................................6 2.1.1 Bone.........................................................................................................................................6 2.1.2 Bioceramic and hydroxyapatite.............................................................................................8 2.2 NANOCARBON REINFORCED COMPOSITES............................................................................................... 12 2.2.1 Introduction ......................................................................................................................... 12 2.2.2 Properties of graphene and carbon nanotube .................................................................. 15 2.2.3 Graphene and carbon nanotube dispersion in ceramic matrix ........................................ 17 2.2.4 Reinforcing efficiency and mechanisms of nanocarbon reinforced ceramics ................. 18 2.2.5 Fabrication of nanocarbon reinforced bioceramic composites ........................................ 23 2.3 SUMMARY ......................................................................................................................................... 34 CHAPTER 3 METHODOLOGY ........................................................................................... 35 3.1 RAW MATERIALS................................................................................................................................. 35 3.2 MIXING PROCEDURE ........................................................................................................................... 35 3.3 DENSIFICATION PROCESS...................................................................................................................... 36 3.4 CHARACTERIZATION TECHNIQUES .......................................................................................................... 36 ii Table of contents CHAPTER 4 EFFECTS OF REDUCED GRAPHENE OXIDE CONTENT AND MIXING METHOD ON REDUCED GRAPHENE OXIDE REINFORCED HYDROXYAPATITE COMPOSITES ............................... 40 4.1 CHARACTERIZATION OF RAW POWDERS.................................................................................................. 40 4.2 EFFECT OF REDUCED GRAPHENE OXIDE CONTENT ..................................................................................... 43 4.2.1 Mixing of rGO and HA powders .......................................................................................... 44 4.2.2 SPS behaviors of mixed rGO-HA composites ..................................................................... 45 4.2.3 Characterization of sintered composites ........................................................................... 46 4.3 EFFECT OF MIXING METHOD ................................................................................................................. 57 4.3.1 Mixing of rGO with HA by BM method .............................................................................. 58 4.3.2 Characterization of SPSed rGO-HA composites mixed by different methods.................. 59 4.4 SUMMARY ......................................................................................................................................... 64 CHAPTER 5 EFFECT OF CARBON MORPHOLOGY ON NANOCARBON REINFORCED HYDROXYAPATITE COMPOSITES ......................................................................................... 65 5.1 EFFECT OF NANOCARBONS’ SHAPE AND SIZE ON NANOCARBON REINFORCED HYDROXYAPATITE COMPOSITES ... 65 5.1.1 Morphologies of mixed CNT-HA and GO-HA powders ...................................................... 65 5.1.2 Characterization of densified rGO-HA, CNT-HA, and GO-HA composites........................ 69 5.2 HYBRIDS OF REDUCED GRAPHENE OXIDE AND CARBON NANOTUBE REINFORCED HYDROXYAPATITE BIOCERAMICS 74 5.2.1 Mixing of rGO, CNT and HA powders ................................................................................. 75 5.2.2 Characterization of SPSed rGO/CNT – HA composites...................................................... 77 5.3 SUMMARY ......................................................................................................................................... 81 CHAPTER 6 TRIBOLOGICAL AND FATIGUE BEHAVIORS OF HYDROXYAPATITE REINFORCED WITH REDUCED GRAPHENE OXIDE AND CARBON NANOTUBE .......................................................... 83 6.1 INTRODUCTION................................................................................................................................... 83 6.2 MICRO-SCALE TRIBOLOGICAL BEHAVIOR ................................................................................................. 84 6.2.1 Wear rate and wear track morphology ............................................................................. 84 6.2.2 Coefficient of friction ........................................................................................................... 87 iii Table of contents 6.2.3 Mechanical properties of the worn surface ....................................................................... 88 6.2.4 Raman Spectrum ................................................................................................................. 91 6.2.5 Wear track microstructure.................................................................................................. 95 6.2.6 Mechanism......................................................................................................................... 102 6.3 NANO-SCALE TRIBOLOGICAL BEHAVIOR ................................................................................................ 103 6.3.1 Experimental setup...........................................................................................................