No.4（2009）11.Application of DLC films for marine elements

Masahiro Kawaguchi, Aya Shimizu, Tetsuto Kajiyama, Sadayuki Watanabe,
Kazuo Morikawa, Yasuyuki Yukawa

  DLC (diamond-like carbon) films have the extraordinary properties of high hardness, low-friction, high wear resistance and so on. Recently, DLC films are utilized in a wide range of friction and wear applications such as cutting tools, mechanical automobile components, die surfaces and hard-disks. On the other hand, DLC films have almost no applications in mechanical components for marine technology although they have good chemical stability. This is caused by presence of pin holes on DLC film surfaces. Particularly the growth of pin holes on the film surface, which implies the degradation of protective ability during the deposition process, causes serious fractures of mechanical components in marine surroundings. In this study, corrosion and wear test of a steel surface coated by the films are accomplished in order to classify the protective ability of the films in marine surroundings. From the results of this study, not only the number of pin holes but also the relative radius of pin holes decrease with increasing deposition time, i.e., the thickness of DLC films. Longer deposition times definitely restrain the growth of pin holes of the films. In addition, the corrosion and wear properties of steel surface in a NaCl solution which simulates marine surroundings are improved by the deposition of DLC films. The size of pin hole expected by SEM (Scanning Electron Microscope) and EDX (Energy Dispersive X-ray Spectroscopy) is discussed in this paper.

Keywords

DLC, pin hole, Plasma Based Ion Implantation and Deposition (PBII&D)

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