Hard amorphous carbon films

Hard amorphous carbon films may either be fully amorphous or contain tiny diamond crystallites. Hydrogen-free films may be deposited on surfaces from graphite by laser ablation or ion sputtering. Hydrogen-containing films are also possible. 

During the past few years the microhardness technique has frequently been applied to the characterization of super-hard-surfaced polymers obtained by ion implantation and to plasma-deposited hard amorphous carbon films (Balta Calleja Fakirov, 1997). These products represent an entirely new class of materials that are lightweight and have the flexibility of polymers combined with a surface microhardness and wear resistance greater than those of metallic alloys (Lee et al., 1996). 

Hard amorphous carbon films is a synonym for DLC films See DLC films... 

R.G. Lacerda, P. Hammer, F. Alvarez, F.C. Marques, Influence of stress on the electron core level energies of noble gases implanted in hard amorphous carbon films. Diam. Relat. Mater. 10(3-7), 956-959 (2001)... 

The wear and degradation of DLC overcoats on a hard disk is a complex process, dependent not only on the head-to-disk material interface but also the environment in which the disk drive operates. Heat and humidity play an important role. Marchon et al. [19,20] have shown that friction and wear rates of amorphous carbon films are dependent on the at-... 

Stress-free Amorphous-Tetrahedral Carbon Films with Hardness Near that of Diamond, Appl. Phys. Lett., Vol. 71,1997, pp. 3820-3822. 

Plasma Synthesis The use of plasma methods has lead to a new range of materials having unique properties. An example is the family of amorphous elemental hydrides (eg cr-C H Of -Si H or-P H) which contain a variable proportion of H from almost zero to 50 atomic %. The carbon films, known variously as "hard carbon", "diamond-like carbon", " a-carbon" etc (9 ) - These layers are of considerable interest because of their optical and abrasion-resistant properties etc (Table I). The properties of these Gr-carbon films, can be tailored by modifying the plasma parameters. 

Extreme hardness is associated with low hydrogen content. These hard carbon films are often referred to as amorphous diamond ... 

Laser ablation of a graphite target (refer to Figure 14) can produce carbon ion plasma. The resulting films are diamond like if the laser power exceeds a certain threshold. The diamond like film is found to consist of a nano-scale mixture of diamond grains embedded in an amorphous carbon matrix. It has the advantage of high hardness yet moderate internal stress. Cuomo et al. compared the ion beam sputtered... 

TetrahedraUy bonded amorphous carbon (ta-C), often conveniently referred to as amorphous diamond (surely an oxymoron), has been a subject of considerable interest because of a hardness comparable to crystalline diamond, a high thermal conductivity (which makes it potentially useful for electronic components), optical transparency and chemical inertness [8]. It differs from a-Si and a-Ge in that it generally has a mixture of sp and sp bonding in the network, but there has been much progress in depositing ta-C films that approach pure sp bonding. Thus a satisfactory model of pure ta-C is needed to serve as a benchmark. 

Standard computer hard disk surfaces (substrates used in this experiment were industrial hard disk surfaces that have been sputter-coated with nominally 100 A of hydrogenated amorphous carbon) can be coated by dip coating with nm thin films of perfluoropolyethers, such as Fomblin ZDOL, from solutions in perfluorohexane. For films thicker than several nm dewetting occurs spontaneously over a period of days to weeks due to the autophobic effect [43]. 

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