Full metadata record
| DC Field | Value | Language |
|---|---|---|
| dc.contributor | Department of Industrial and Systems Engineering | en_US |
| dc.contributor.advisor | To, Sandy (ISE) | en_US |
| dc.contributor.advisor | Yip, Lenny (ISE) | en_US |
| dc.creator | Kwok, Fung Ming | - |
| dc.identifier.uri | https://theses.lib.polyu.edu.hk/handle/200/14603 | - |
| dc.language | English | en_US |
| dc.publisher | Hong Kong Polytechnic University | en_US |
| dc.rights | All rights reserved | en_US |
| dc.title | Theoretical and experimental investigation of magnetic field assisted hot filament chemical vapour deposition for diamond coated tools | en_US |
| dcterms.abstract | This research presents an innovative approach to diamond coating by integrating magnetic fields into the Hot Filament Chemical Vapor Deposition (HFCVD) process. This novel method addresses the traditional challenges of HFCVD, such as slow growth rates and inconsistent film uniformity, by leveraging magnetic fields to enhance efficiency and quality in diamond coating technology. | en_US |
| dcterms.abstract | The study begins by optimizing key parameters of the HFCVD process, including methane concentration, substrate temperature, and chamber pressure. Through experimental design, response surface methodology, and parameter optimization, significant improvements in film uniformity and growth kinetics were achieved. After obtaining the optimum coating parameters for diamond film in HFCVD, an application of magnetic field in HFCVD is demonstrated. Notably, applying a 400 mT magnetic field increased diamond nucleation rates by 45% and overall growth rates by nearly 45%, crucial for producing high-quality, consistent films for industrial applications. Incorporating a magnetic field during the HFCVD process also enhanced the structural and morphological characteristics of the diamond films. The magnetic field facilitated the formation of larger, more uniform columnar grains with a dominant (111) crystallographic orientation, known for superior mechanical strength and thermal conductivity. These properties are advantageous for high-performance applications, such as cutting tools and thermal management systems. The research further explored the impact of rotational dynamics in the magnetic field system during deposition. Rotating the magnetic field at speeds up to 2 RPM significantly improved the uniformity and thickness of the diamond films, addressing issues related to non-uniform magnetic influence and plasma stability common in static configurations. Additionally, various magnetic field configurations, including balanced and unbalanced setups, were investigated. The South-North (SN) orientation proved particularly effective in promoting uniform grain size and consistent coating thickness. | en_US |
| dcterms.abstract | Complementing the experimental work, comprehensive Finite Element Modelling (FEM) was employed to analyse the effects of magnetic fields on temperature distribution and reactive gas flow within the HFCVD reactor. The simulations demonstrated that the magnetic field optimized the distribution of reactive species, improved plasma stability, and ensured a uniform temperature profile across the substrate, providing predictive insights into optimal conditions for diamond film growth. | en_US |
| dcterms.abstract | This study significantly advances HFCVD technology by demonstrating the potential of magnetic field assistance in diamond coating. It promises to reduce production costs, increase productivity, and enhance the performance of cutting tools, particularly in specialized applications. The successful integration of this technology offers high levels of efficiency and quality, reshaping the landscape of cutting tool manufacturing and beyond. | en_US |
| dcterms.extent | xviii, 179 pages : color illustrations | en_US |
| dcterms.isPartOf | PolyU Electronic Theses | en_US |
| dcterms.issued | 2026 | en_US |
| dcterms.educationalLevel | Ph.D. | en_US |
| dcterms.educationalLevel | All Doctorate | en_US |
| dcterms.accessRights | open access | en_US |
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