Crystalline diamond particles into diamond-like carbon films: The influence of the particle sizes on the electrochemical corrosion resistance

Crystalline diamond (CD) particles are incorporated into diamond-like carbon (DLC) films in order to prevent CD–DLC electrochemical corrosion. In this paper, the influence of the diamond particle sizes on the electrochemical corrosion resistance of CD–DLC films was investigated. The films were grown over 304 stainless steel using plasma enhanced chemical vapor deposition. CD particles with 4 nm, 250 nm, 500 nm and 2–3 µm in diameter were incorporated into DLC during the deposition process. The investigation of CD–DLC electrochemical corrosion behavior was performed using potentiodynamic method. The results show that both protection efficiency and impedance increase with the decrease of ID/IG ratio. It means the increase of sp3 bonds in DLC films reduces its electrochemical corrosion, improving the electrochemical protection efficiency and the impedance. Our results pointed out that CD–DLC films are promising corrosion protective coatings in aggressive solutions.