title: Ultrathin Carbon with Interspersed Graphene/Fullerene-like Nanostructures: A Durable Protective Overcoat for High Density Magnetic Storage.
abstract: One of the key issues for future hard disk drive technology is to design and develop ultrathin (<2 nm) overcoats with excellent wear- and corrosion protection and high thermal stability. Forming carbon overcoats (COCs) having interspersed nanostructures by the filtered cathodic vacuum arc (FCVA) process can be an effective approach to achieve the desired target. In this work, by employing a novel bi-level surface modification approach using FCVA, the formation of a high sp(3) bonded ultrathin (~1.7 nm) amorphous carbon overcoat with interspersed graphene/fullerene-like nanostructures, grown on magnetic hard disk media, is reported. The in-depth spectroscopic and microscopic analyses by high resolution transmission electron microscopy, scanning tunneling microscopy, time-of-flight secondary ion mass spectrometry, and Raman spectroscopy support the observed findings. Despite a reduction of ~37% in COC thickness, the FCVA-processed thinner COC (~1.7 nm) shows promising functional performance in terms of lower coefficient of friction (~0.25), higher wear resistance, lower surface energy, excellent hydrophobicity and similar/better oxidation corrosion resistance than current commercial COCs of thickness ~2.7 nm. The surface and tribological properties of FCVA-deposited COC was further improved after deposition of lubricant layer.
authors.affiliation: Department of Electrical and Computer Engineering, National University of Singapore, 117583 Singapore.
authors.forename: Neeraj
authors.initials: N
authors.lastname: Dwivedi
authors.affiliation: Department of Electrical and Computer Engineering, National University of Singapore, 117583 Singapore.
authors.forename: Nalam
authors.initials: N
authors.lastname: Satyanarayana
authors.affiliation: Department of Electrical and Computer Engineering, National University of Singapore, 117583 Singapore.
authors.forename: Reuben J
authors.initials: RJ
authors.lastname: Yeo
authors.affiliation: Graphene Research Centre and Department of Chemistry, National University of Singapore, 117543 Singapore.
authors.forename: Hai
authors.initials: H
authors.lastname: Xu
authors.affiliation: Graphene Research Centre and Department of Chemistry, National University of Singapore, 117543 Singapore.
authors.forename: Kian
authors.initials: K
authors.lastname: Ping Loh
authors.affiliation: Institute of Materials Research and Engineering (IMRE), A*STAR (Agency for Science, Technology, and Research), 3 Research Link, 117602 Singapore.
authors.forename: Sudhiranjan
authors.initials: S
authors.lastname: Tripathy
authors.affiliation: Department of Electrical and Computer Engineering, National University of Singapore, 117583 Singapore.
authors.forename: Charanjit S
authors.initials: CS
authors.lastname: Bhatia