Carbon overcoat

Magneto-optic and magnetic disc materials DyCo, TbFeCo, garnets, sputtered magnetic media (CoNiCr alloys and their carbon overcoats). 

Yamamoto, T., Hyodo, H., Tsuchitani, S., and Kaneko, R., Ultrathin Amorphous Carbon Overcoats by Filtered Cathodic Arc Deposition, IEEE Trans. Magn., Vol. 39, 2003, pp. 2201-2204. 

Fig. 13. Increase of Co concentration above the carbon overcoat on CoCr/C disks exposed to temperatures up to 90 °C and RH up to 90% [154]. (Reprinted by permission of The IEEE).

Figure 1.11. Spreading profiles of Zdol (M — 2,500 g/mol) on different carbon overcoats at 20 min, 7 h, 24 h, and 46 h after coating the films [60],...

We constructed stability diagrams from Eq. (1.25) using our data for the surface energies of various PFPEs and carbon overcoats, which are shown in Figure 1.27 [7]. These stability diagrams provide molecular criteria for the uniformity of films (or dewetting). 

A hard disk typically consists of an Al-Mg alloy (or glass substrates), a NiP undercoat, magnetic layer, carbon overcoat, and a very thin layer of lubricant, as illustrated in Fig. 1.1. Since the Al-Mg alloy is mechanically soft, a hard undercoat is applied to provide adequate impact resistance to the head-disk interactions. The magnetic layer where the information is stored is typically sputtered directly onto a bare NiP/Al-Mg disk substrate. A carbon overcoat is sputtered to enhance wear and/or corrosion resistance. Finally, a molecularly thin layer of PFPEs (the subject of this chapter) along with airbearing is added to further reduce both the wear of the overcoat and stiction between the head and disk. 

R. Z. Lei, Fundamental Studies of Molecular Interactions between Lubricants and Contaminants on Amorphous Carbon Overcoats, Ph.D. thesis, Carnegie Mellon Univ., Pittsburgh, PA, 2002. 

P. H. Kasai and A. M. Spool, Z-DOL and carbon overcoat Bonding mechanism, IEEE Trans. Magn. 37 929-933 (2001). 

Lubricani Carbon overcoat CoPtCrb magnetic layer 6 A ruthenium layer CoPtCrb magnetic layer Cr underlayer... 

C. M. Ma, X. Kim, M.C. Jhon, M.S. Simulation of ultra-thin lubricant films spreading over various carbon overcoats. J. Appl. Phys. 2000, 87 (9), 6164-6166. 

C.M. Mate, Nanotribology of lubricated and unlubricated carbon overcoats on magnetic disks studied by friction force microscopy, Surf. Coat. Technol., 62, 373-379, 1993. 

Composition of deposited layers Thickness of deposited layers Defect characterization Particle identification Process residue identification Lubricant type and thickness Carbon overcoat composition Magnetic layer composition Magnetic layer thickness Defect/contamination identification Failure analysis... 

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