Diamond Like Carbon Research Papers (original) (raw)

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- Engineering, Materials Science, Technology, Plasma Processing

A novel technique for synthesizing a diamond-like carbon (DLC) film by pulsed laser deposition (PLD) is proposed. In the technique, additional lasers irradiated the plume in order to increase the density of the ionic carbon. By irradiating with an ArF excimer laser, the emission intensity of the atomic carbon was increased greatly. By irradiating with the third harmonic output and the fundamental output of an Nd:YAG laser, the emission intensity of the atomic and ionic carbon also increased greatly. The sp3 content increased from 51% without to 76% with two additional irradiation of the fundamental output of two Nd:YAG laser beams. The differences in the binding energy and surface morphology between the films with and without the irradiation of the additional lasers to the plume were observed by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM), respectively.

- by Tatsuya Shinozaki
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- Carbon, Atomic Force Microscopy, Pulsed Laser Deposition, Diamond Like Carbon
- by Mohammed Zikry
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- Materials Engineering, Mechanical Engineering, Microstructure, Modeling
- by Chung-Kwei Lin
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- Materials Engineering, Condensed Matter Physics, Carbon, Surface Roughness
- by Yu. S. Ponosov
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- Materials Engineering, Low Frequency, High Frequency, Diamond Like Carbon

Potential applications of diamond-like carbon (DLC) coatings range from precision tools and biomedical implants to micro mechanical devices and engine components. Where uniform coatings are required on substrates with complex geometries, plasma enhanced chemical vapour deposition (PECVD) is often a preferred deposition method. As a non-line of sight process, the geometry of the substrate is often considered negligible. For this reason analysis of PECVD coatings, such as amorphous carbon, has mostly been concerned with reactor deposition variables, such as bias voltage, pressure and gas ratios. Samples are therefore usually prepared and positioned to minimise the influence of other variables. By depositing nominally similar DLC films on silicon samples positioned horizontally and vertically on the reactor cathode plate it was possible to examine the variations in the coating characteristics and mechanical properties that occur due to the geometry of the substrate being coated. Topographic measurements and analysis of bonding structures revealed significant heterogeneity in the coatings. Electron microscopy showed variation in surface structure as well as thickness disparities of up to 50% in the vertical sample. Atomic force microscopy showed roughness, Ra, varied from 0.37 nm to 15.4 nm between samples. Raman spectroscopy highlighted variations in the sp2/sp3 bonding ratios whilst micro wear tests demonstrated how these variations reduce the critical load performance. These effects are explained in terms of the deposition mechanisms involved and are related to variation in deposition species and geometrical field enhancements within the deposition chamber. Improved understanding of these local variations will aid in the optimization of coatings for complex substrate geometries.

- by Benjamin Jones
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- Plasma Physics, Surface Science, Thin Films and Coatings, Raman Spectroscopy
- by Alison Crossley
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- Engineering, Technology, Raman Spectroscopy, Titanium
- by Prashant Kumta
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- Materials Engineering, Mechanical Engineering, Diamond Like Carbon, Medical Device
- by Mihail Ionescu
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- Biomaterials, Macrophages, Multidisciplinary, Surface Roughness
- by P. Cossari and +3
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- Engineering, Technology, Atomic Force Microscopy, Physical sciences
- by R. Mansano and +1
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- Materials Engineering, Chemical Engineering, Raman Spectroscopy, Manufacturing Engineering

ABSTRACT In this paper, the unique properties of thin diamond-like layers are presented. Diamond-like carbon (DLC) films have been developed as colour coatings for a range of substrates. They can be used in a wide variety of applications, including jewellery and other applications where colours need to be combined in a tough, hard-wearing, aesthetically appealing and biocompatible application. DLC films were synthesised by the radio frequency plasma activated chemical vapour deposition (RFPACVD) technique, running at 13.56 MHz. The possibility of the repeatable manufacturing of such coatings makes them a new possible material in jewellery. The coatings have been examined using a range of characterisation tools, including X-ray elemental microanalysis, Raman spectroscopy, atomic force microscopy, colourimetric analysis, ellipsometry and the measurement of nanohardness and adhesion. The examinations show that the technology can be applied in many fields. An example of the jewellery application is afforded by the UK Millennium Medal, created by the well-known English artist Wendy Ramshaw OBE, who worked closely with our team.

- by Alessio Mezzi
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- Engineering, Technology, Atomic Force Microscopy, Physical sciences
- by Mariano Anderle
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- Materials Engineering, Chemical Engineering, Scanning Electron Microscopy, X Rays
- by Julie Cairney and +1
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- Materials Engineering, Chemical Engineering, Cultural Studies, Raman Spectroscopy
- by Sylvain J Ballandras
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- Engineering, Acoustics, Silicon, Crystallization
- by Hasan Mahmud
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- Materials Engineering, Condensed Matter Physics, Magnesium, Silicon Carbide
- by Bojan Podgornik
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- Materials Engineering, Mechanical Engineering, Carbon, Wear

Chemical vapour deposition (CVD) is used to grow diamond and diamond like carbon (DLC) films. The condition under which the formation of sp3 carbon takes place is a metastable one. There is a requirement of seed material to start the formation of diamond phase, and moreover there are substrates which favour its growth. There is still much scope of research in understanding the metastable synthesis of diamond. Such coatings need to be physically characterised and mechanically polished down to very smooth top surface for any meaningful industrial application. The work plan of the present thesis can be divided into six categories:
1. The nucleation and growth of CVD diamond is first investigated using conventional diamond micron-grit suspension seeding of silicon substrates.
2. Secondly, emphasis was given on the detonation nanodiamond (DND) seeding technique for understanding the metastable growth process of the sp3 phase. It was found that CVD growth conditions lead to capillary rise in pressure inside the vacuum chamber, which thereby replicates high pressure high temperature (HPHT) environment, thus contradicts the prevailing knowledge of metastable diamond synthesis of CVD diamond.
3. Such CVD as-grown diamond films were then characterised using different tools, like XRD, Raman, SEM, XPS etc.
4. Since, 915 MHz microwave frequency was used to grow CVD diamond, it led to coating non-uniformity, over large areas. So, such large area diamond deposition characteristics were then necessary to study.
5. Next, polishing was done on such large area diamond coatings with evaluation of its efficacy.
6. Separately, diamond like nanocomposite (DLN) coating was also deposited by a separate PECVD reactor and characterised for knee implant bio-coating application.
In the first chapter of the thesis introductory remarks have been made on the issues involving each of the above six subjects. Second chapter describes the experimental techniques adapted in the thesis work. The third chapter discusses the results obtained from these experiments to address each of the above six sub-categories. The final and fourth chapter concludes the thesis work highlighting the important observations of this PhD study.

- by Awadesh Mallik
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- Diamonds, Diamond Like Carbon, Nucleation and Growth, CVD grown Diamond films
- by Hasan Mahmud and +1
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- Condensed Matter Physics, Thin Films and Coatings, Tribology, Immersion and Experience
- by Ryan Evans and +1
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- Mechanical Engineering, Thin Film, Diamond Like Carbon, Chromium

The aim of the present work is to identify an environmentally clean coating process that will present lower influence in the Ti–6Al–4V fatigue strength. Axial fatigue tests of Ti–6Al–4V alloy TiN, CrN and WC:H (tungsten containing diamond-like carbon) Physical Vapor Deposition (PVD) coated was evaluated. Decrease in fatigue life was observed for coated specimens in comparison to base metal. Scanning Electron Microscopy technique was used to observe crack origin sites and coating thickness. DLC coating provides higher Ti–6Al–4V alloy PVD coated fatigue strength due to lower defects presence and the chromium interlayer, which acts as a barrier to fatigue crack propagation.

- by Ronaldo Ruas
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- Mechanical Engineering, Civil Engineering, Scanning Electron Microscopy, Fatigue
- by Yin-Yu Chang
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- Engineering, Technology, Physical sciences, Diamond Like Carbon

This review focuses on low-pressure plasma modification methods to produce hydrophobic coatings and surface modifications on biomaterials. Plasma-deposited fluoropolymer, siloxane, and diamond-like carbon (DLC) coatings are reviewed in terms of process developments, monomers used, stability and aging properties, and their behavior in adsorption of proteins, cell attachment, and bacterial adhesion. These hydrophobic coatings are stable with correct selection of monomers and process conditions, but the plasma polymerized siloxane and fluorocarbons have been mainly applied in biochip and test kits rather than in blood-contact applications. Similarly, the surface characteristics and interfacial bonding of DLC coatings play a crucial role in their successful implementation

- by Kim S Siow
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- Biomaterials Engineering, Plasma Physics, Biomedical Engineering, Biomaterials
- by Narendra Dahotre
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- Materials Engineering, Condensed Matter Physics, Metal matrix composite, Surface Roughness
- by Bojan Podgornik
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- Materials Engineering, Mechanical Engineering, Lubrication, Wear
- by wen meng
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- Materials Engineering, Mechanical Engineering, Carbon, Wear
- by Sébastien Equey
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- Mechanical Engineering, Tribology, Atomic Force Microscopy, Diamond Like Carbon
- by Huiwen Liu
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- Raman Spectroscopy, PHOTOELECTRON SPECTROSCOPY, Atomic Force Microscopy, Multidisciplinary
- by Dimitar Mitev
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- Materials Engineering, Chemical Engineering, FTIR spectroscopy, Manufacturing Engineering
- by Sébastien Equey
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- Materials Engineering, Mechanical Engineering, Wear, Phosphorus
- by Joze Vizintin
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- Mechanical Engineering, Lubrication, Fretting, Tribology
- by Andy Horsewell
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- Materials Engineering, Condensed Matter Physics, Diamond Like Carbon, Functionally Graded
- by Jean-yves Rauch
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- Materials Engineering, Condensed Matter Physics, Diamond Like Carbon, Plasma Enhanced Chemical vapour deposition (PECVD)
- by Gustaaf Schoukens
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- Mechanical Engineering, Tribology, Diamond Like Carbon, Polyethylene
- by M. Griepentrog
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- Materials Engineering, Mechanical Engineering, Wear, Diamond Like Carbon
- by Stefania Bruschi
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- Materials Engineering, Mechanical Engineering, Sheet Metal Forming, Lubrication
- by sam zhang
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- Materials Engineering, Condensed Matter Physics, Transmission Electron Microscopy, Diamond Like Carbon
- by Tomi Laurila
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- Materials Engineering, Analytical Chemistry, Electrochemistry, Carbon Nanotubes
- by F. Rogemond and +2
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- Engineering, Thermodynamics, Technology, PHOTOELECTRON SPECTROSCOPY
- by Yin-Yu Chang
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- Materials Engineering, Condensed Matter Physics, Titanium, Surface Coatings
- by Alex A Volinsky
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- Engineering, Technology, Microstructure, Raman Spectroscopy
- by Juan Matthews
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- Materials Engineering, Condensed Matter Physics, Carbon, RADIATION DAMAGE