Abstract
Hard carbon thin films were synthesized on Si (100) and quartz substrates by the Pulsed Laser Deposition (PLD) technique in vacuum or methane ambient to study their suitability for applications requiring high mechanical resistance. The deposited films’ surface morphology was investigated by scanning electron microscopy, crystalline status by X-ray diffraction, packing and density by X-ray reflectivity, chemical bonding by Raman and X-ray photoelectron spectroscopy, adherence by “pull-out” measurements and mechanical properties by nanoindentation tests. Films synthesized in vacuum were a-C DLC type, while films synthesized in methane were categorized as a-C:H. The majority of PLD films consisted of two layers: one low density layer towards the surface and a higher density layer in contact with the substrate. The deposition gas pressure played a crucial role on films thickness, component layers thickness ratio, structure and mechanical properties. The films were smooth, amorphous and composed of a mixture of sp3-sp2 carbon, with sp3 content ranging between 50% and 90%. The thickness and density of the two constituent layers of a film directly determined its mechanical properties.
Highlights
Bulk carbon has two crystalline forms: diamond and graphite
We present in premiere a study on the influence of the deposition pressure on the thickness and density of such bi-layer structures for films deposited with the same number of pulses, and how their proportion can influence the overall physical properties of the carbonaceous coating
Initial deposition experiments were conducted with substrates kept at room temperature (RT)
Summary
Bulk carbon has two crystalline forms: diamond and graphite. Bonds between carbon atoms are simple (sp hybridization), whilst in graphite atoms are linked by a double bond, one σ and one π (sp hybridization) [1]. Amorphous carbon structures with atoms bonded mainly by simple bonds can be obtained. This type of carbon is known in the literature as “diamond-like carbon” (DLC) [2]. The carbon films are usually used in the mechanical and metallurgical industries as protective coatings for cutting blades, magnetic disks, and engine parts, as well as in the glass industry for scratch proof surfaces, and in medicine as protective coatings for implants and prostheses [5]. Carbon films can be found in the literature with the denominations ta-C (tetrahedral amorphous carbon) for films with more than 90% sp content, a-C (amorphous carbon) for coatings with sp between 30% and 80%
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
