Toughness characterization of DLC and Ti doped DLC

• Main Author: Tey, Xiang Wei.
• Other Authors: Sam Zhang Shanyong
• Format: Final Year Project
• Language: English
• Published: 2010
• Subjects: DRNTU::Engineering::Mechanical engineering
• Online Access: http://hdl.handle.net/10356/39689
• Institution: Nanyang Technological University

Abstract As DLC and DLC based ceramic thin films are increasingly finding their way in engineering applications, thin film toughness assessment becomes important. However, it has not been thoroughly explored. This project will give a systematical investigation into assessing the toughness of diamond-like carbon (DLC) and Ti doped DLC (nc-TiC/a-C) using existing qualitative and quantitative methods. Ti doped DLC contains both nanocrystalline titanium carbide (nc-TiC) phase and amorphous carbon (a-C) as the matrix. Preparation of the DLC and Ti doped DLC were prepared based on their substrate and power density respectively. Relationship between the hardness, microstructure and toughness of the two thin ceramic films will be looked into. Insights from the experimental results showed how fracture toughness of DLC changes with substrate bias. The fracture toughness of DLC films decreases with substrate bias. Also, by the incorporation of Ti element which forms the nanocrystalline phase in the DLC matrix. It was observed that the fracture toughness varies as the peak of the nc-TiC(220) increases. It also showed the problems and difficulty in using both models of the energy-based method in calculating the fracture toughness of the nanocomposite thin film samples. The studies showed that more work would need to be done into the experimental and theoretical procedures of measuring fracture toughness of thin films.