Effects of Substrate Pulse Bias on Corrosion Behavior of Tetrahedral Amorphous Carbon Thin Films in Acidic and Chloride Solutions

Filtered cathodic vacuum arc (FCVA) deposition technology was applied to prepare tetrahedral amorphous carbon (taC) thin films with different substrate pulse biases. Their structure, adhesion strength, and corrosion behavior in 5 × 10−2 M hydrochloric (HCl), sodium chloride (NaCl), calcium chloride (CaCl2), lead (II) chloride (PbCl2), and mercury (II) chloride (HgCl2) solutions were studied with respect to the substrate pulse bias. Increasing the substrate pulse bias from 0 to 1000 V increased the graphitization of the taC thin films and thereby resulted in a 9.9% increase in their adhesion strength from 406 mN to 446 mN. The taC thin films exhibited the lowest (8.48 × 104 Ω to 11.55 × 104 Ω) and highest (146.89 × 104 Ω to 387.44 × 104 Ω) corrosion resistance in the PbCl2 and HgCl2 solutions, respectively, while they had higher corrosion in the HCl (62.07 × 104 Ω to 131.73 × 104 Ω) solution than in both the NaCl (143 × 104 Ω to 231.31 × 104 Ω) and CaCl2 (102.13 × 104 Ω to 351.92 × 104 Ω) solutions. Nevertheless, the taC thin films with higher substrate pulse biases had lower corrosion resistance in all the solutions used in this study. The substrate pulse bias emerged as a significant parameter in the FCVA deposition process, playing a crucial role in influencing the structure, adhesion strength, and corrosion resistance of taC thin films.