Thermal‐ and electron‐stimulated chemistry of a cyclotriphosphazene lubricant on a magnetic disk with a hard carbon overcoat

1995 ◽  
Vol 13 (4) ◽  
pp. 1867-1871 ◽  
Author(s):  
Jong‐Liang Lin ◽  
John T. Yates
Keyword(s):  
Hard Carbon ◽  
Carbon Overcoat ◽  
Magnetic Disk

Study of Tribochemical Processes on Hard Disks Using Photoemission Electron Microscopy

1999 ◽  
Vol 121 (4) ◽  
pp. 961-967 ◽  
Author(s):  
Simone Anders ◽  
Thomas Stammler ◽  
Walton Fong ◽  
Chao-Yuan Chen ◽  
David B. Bogy ◽  
...  
Keyword(s):  
Hard Disks ◽  
Chemical Modifications ◽  
Hard Carbon ◽  
Carbon Overcoat ◽  
Chemical Changes ◽  
X Ray ◽  
Tribochemical Processes ◽  
Carbon Coated ◽  
Photoemission Electron ◽  
Wear Tests

The interface between hard disk and slider involves mechanical and tribochemical processes between the hard carbon overcoat of the disk, the lubricant, and the carbon coated or uncoated slider surface. These processes have been studied by two related X-ray techniques—Near Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy and Photoemission Electron Microscopy (PEEM) using X-rays. NEXAFS allows studying the elemented composition and chemical bonding in a material, whereas PEEM combines this ability with imaging of the sample. Lubricated and unlubricated disks were worn under various conditions using carbon coated and uncoated sliders. The wear tracks on the hard disks were investigated using PEEM to find chemical and elemental changes caused by the wear. Local NEXAFS spectra taken in wear tracks using the PEEM microscope show no chemical changes on unlubricated disks, just a reduction of the hard carbon overcoat thickness. On lubricated disks remarkable chemical modifications of the lubricants caused by the wear are observed if the disks failed the wear tests. The chemical changes are manifested in a formation of various new carbon-oxygen (mostly carboxylic) bonds in the wear tracks and in a strong reduction of the amount of fluorine and carbon. The chemical modifications were only found inside the wear tracks and are clearly caused by the wear. It was found that lubricant degradation is not solely a mechanical process of molecule scission but accompanied by oxidation reactions. The chemical changes were strongly correlated to the tribological behavior of the disks: the worse the disks performed in the wear tests, the stronger were the chemical modifications.

scholarly journals Corrosion of Thin Film Magnetic Disk: Galvanic Effects of the Carbon Overcoat

1989 ◽  
Vol 136 (1) ◽  
pp. 42-46 ◽  
Author(s):  
V. Brusic ◽  
M. Russak ◽  
R. Schad ◽  
G. Frankel ◽  
A. Selius ◽  
...  
Keyword(s):  
Thin Film ◽  
Carbon Overcoat ◽  
Magnetic Disk

PREPARATION OF ULTRA THIN CARBON OVERCOAT FOR MAGNETIC RECORDING MEDIUM BY HOT FILAMENT PLASMA CVD

2002 ◽  
Vol 16 (06n07) ◽  
pp. 973-977 ◽  
Author(s):  
S. FUJIMAKI ◽  
T. OHNO ◽  
Y. KOKAKU ◽  
Y. HONDA
Keyword(s):  
Low Pressure ◽  
High Density ◽  
Thin Coating ◽  
Plasma Cvd ◽  
Hard Carbon ◽  
Carbon Overcoat ◽  
Discharge System ◽  
Hot Filament ◽  
Filament Plasma ◽  
Density Plasma

The deposition process of carbon coating by plasma CVD was studied for the development of a high-density magnetic disk with an ultra thin overcoat of about 4nm thickness. A hot filament discharge system was installed to disk production equipment for the simultaneous deposition of a carbon thin coating on both sides of the disk. The hot filament high-density plasma, in a low-pressure atmosphere of 0.5Pa, was found to be more advantageous, compared with other CVD sources, such as radio frequency plasma, in deposition of the hard carbon thin coating on a negatively biased substrate with ion incidence to the sample. Ion impinging on the substrate was evaluated by calculating its contribution ratio, roughly, from growth rate and bias current density, then examined in relation to the hardness of the carbon thin coatings. In conclusion, hot filament plasma, as a stable CVD source, enables the deposition of the hard carbon overcoat at over 10GPa at the rate of about 1 nm/s, by generating high-density plasma in a low-pressure atmosphere.

Microstructures in Lubricant Thin Layers at the Magnetic Disk Surface, Observed Using Cryogenic Atomic Force Microscopy

2006 ◽  
Vol 59 (6) ◽  
pp. 394
Author(s):  
Teiji Kato ◽  
Takayuki Nakakawaji
Keyword(s):  
Atomic Force Microscopy ◽  
Disk Surface ◽  
Thin Layers ◽  
Solid Surfaces ◽  
Carbon Overcoat ◽  
Magnetic Disk ◽  
Force Microscopy ◽  
Atomic Force ◽  
Pfpe Lubricant ◽  
Atomically Flat

Cryogenic Atomic Force Microscopy (AFM) was used to observe perfluoropolyether (PFPE) lubricant molecules at atomically flat solid surfaces and at a magnetic disk surface to understand the lubricity of ultra-thin (1 nm) lubricant layers at the hard disk surface. Molecular imaging of PFPE lubricant molecules reveals the formation of reversed micelle structures at comparatively non-polar solid surfaces such as gold or the carbon overcoat of magnetic disks.

ChemInform Abstract: Corrosion of Thin Film Magnetic Disk: Galvanic Effects of the Carbon Overcoat.

ChemInform ◽  
1989 ◽  
Vol 20 (18) ◽  
Author(s):  
V. BRUSIC ◽  
M. RUSSAK ◽  
R. SCHAD ◽  
G. FRANKEL ◽  
A. SELIUS ◽  
...  
Keyword(s):  
Thin Film ◽  
Carbon Overcoat ◽  
Magnetic Disk

Preparation of high-crystallinity synthetic graphite from hard carbon-based carbon black

2021 ◽  
Vol 127 (2) ◽  
Author(s):  
Min Il Kim ◽  
Jong Hoon Cho ◽  
Jin Ung Hwang ◽  
Byong Chol Bai ◽  
Ji Sun Im
Keyword(s):  
Carbon Black ◽  
Hard Carbon ◽  
High Crystallinity ◽  
Synthetic Graphite ◽  
Carbon Based

Soybean roots-derived N, P Co-doped mesoporous hard carbon for boosting sodium and potassium-ion batteries

Carbon ◽  
2021 ◽  
Vol 178 ◽  
pp. 233-242
Author(s):  
Shi Tao ◽  
Wei Xu ◽  
Jihui Zheng ◽  
Fanjun Kong ◽  
Peixin Cui ◽  
...  
Keyword(s):  
Potassium Ion ◽  
Hard Carbon ◽  
Soybean Roots ◽  
Sodium And Potassium ◽  
Co Doped

scholarly journals Enabling 6C Fast Charging of Li‐Ion Batteries with Graphite/Hard Carbon Hybrid Anodes

2020 ◽  
pp. 2003336
Author(s):  
Kuan‐Hung Chen ◽  
Vishwas Goel ◽  
Min Ji Namkoong ◽  
Markus Wied ◽  
Simon Müller ◽  
...  
Keyword(s):  
Li Ion Batteries ◽  
Hard Carbon ◽  
Fast Charging ◽  
Li Ion

scholarly journals Combination of solid state NMR and DFT calculation to elucidate the state of sodium in hard carbon electrodes

2016 ◽  
Vol 4 (34) ◽  
pp. 13183-13193 ◽  
Author(s):  
Ryohei Morita ◽  
Kazuma Gotoh ◽  
Mika Fukunishi ◽  
Kei Kubota ◽  
Shinichi Komaba ◽  
...  
Keyword(s):  
Solid State ◽  
Solid State Nmr ◽  
Dft Calculation ◽  
Magic Angle Spinning ◽  
The State ◽  
Mas Nmr ◽  
Magic Angle ◽  
Multiple Quantum ◽  
Hard Carbon ◽  
Angle Spinning

We examined the state of sodium electrochemically inserted in HC prepared at 700–2000 °C using solid state Na magic angle spinning (MAS) NMR and multiple quantum (MQ) MAS NMR.

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