Temperatures diamond-like carbon

One of such unique coatings is Diamond Like Carbon (DLC). The conventional synthesis of synthetic diamonds requires extremely high temperatures and pressures. By PECVD, Diamond Like Carbon is created under mild conditions by the decomposition of methane in H2/CH4 mixture. The applications of DLC are numerous coatings for cutting tools, optical fibres, electronic devices for reading magnetic tapes, or even protective coatings in chemical reactors. 

Graphite is probably the most widely used lamellar solid lubricant. Unlike M0S2, graphite has a lower friction and lower wear in the presence of moisture than in vacuum. Therefore, graphite is not recommended for vacuum or high-temperature applications. But another form of carbon, amorphous hydrogenated carbon films (also called diamond-like carbon), has the reverse behavior It works extremely well in vacuum, but its friction coefficient is increased by the presence of moisture [37]. 

Chiang KT, Yang L, Wei R, Coulter K (2008) Development of Diamond-Like Carbon-Coated Electrodes for Corrosion Sensor Applications at High Temperatures. Thin solid films 517 1120-1124. 

By using chemical vapour deposition (CVD) technology at a relatively low temperature, Nissin Electric, Kyoto, Japan, claims it is able to apply diamond-like carbon coatings to materials such as plastics and rubber, improving their properties of friction, abrasion resistance and insulation. 

During carbonization of PAN, an extensive-random network of graphitic ribbons is formed which heis a stable configuration. I n addition, it is speculated that some tetrahedral (sp (diamond) bonds are formed (which would account for the hardness of these materials). 1 1 The presence of diamond structure in a similar material, diamond-like carbon, is well established (see Ch. 14). The diamond structure is reviewed in Ch. 2, Sec. 3.0. These two factors, ribbon network and tetrahedral bonds, would preventfurther ordering ofthe staicture, regardless of the graphitization temperature. 

A 1 jim thick diamond-like carbon film is deposited at 500 °C on a Ti alloy substrate. The film with elastic modulus Ef = 500 GPa and Poisson ratio Ui = 0.2, is essentially free of any internal stress at the deposition temperature. When cooled to the temperature 20 °C, however, an equibiaxial compressive mismatch stress of 5 GPa is expected to exist in the film as a consequence of thermal mismatch with the substrate. An unbonded circular patch, 30 gm in diameter, developed at the film-substrate interface during film deposition. Determine whether the film buckles upon cooling to 20 °C If so, determine the temperature at which buckling begins. 

Figure 32 The C—H vibrational spectra of a DLC film before and after 1-hr thermal annealing at different temperatures (three upper curves) and after restoration (lower curve) [73]. (Reproduced from Journal of Non-Crystalline Solids, 227-230, Ivanov-Omskii, V. L, Bonded and non-bonded hydrogen in diamond-like carbon, pp. 627-630. Copyright 1998, with permission from Elsevier... 

Liu WJ, Guo XJ, Chang CL, Lu JH. Diamond-like carbon thin films synthesis by low temperature atmospheric pressure plasma method. Thin Solid Eilms 2009 517(14) 4229-32. 

Diamond oxidation occurs at 1,070 K preferentially at grain boundaries, local defects, and in the diamond-like carbon phase [86, 87], Molecular oxygen adsorption happens to the clean (111) and (110) surfaces of diamond at room temperature [88]. Thermal desorption produces CO from both surfaces. Apart firom a low-temperature desorption peak, TDS shows two CO desorption peaks at 1,060 and 1,300 K for the C(lll)—(2 x 1) surface, whereas only one desorption peak presents in the 1,030-1,160 K range for the C(llO) surface. 

Ni, W., Cheng, Y. T., Weiner, A. M. and Perry, T. A. Tribological Behavior of Diamond-Like-Carbon (DLC) Coatings Against Aluminum Alloys at Elevated Temperatures, Sat/aee and Coatings Technology, Vol. 201,2006, pp. 3229-34. 

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