Characterization of ta-C film on micro arc oxidation coated titanium alloy in simulated seawater

• Published in: Diamond and related materials 2021-08, Vol.117, p.108483, Article 108483
• Main Authors: Lan, Nan, Yang, Wei, Gao, Wei, Guo, Peng, Zhao, Chen, Chen, Jian
• Format: Article
• Language: English
• Subjects: Cathodic coating (process); Ceramic bonding; Ceramic coatings; Coefficient of friction; Corrosion currents; Corrosion potential; Corrosion prevention; Corrosion resistance; Corrosive wear; Marine environment; Mechanical properties; Micro arc oxidation; Microstructure and properties; Morphology; Oxidation; Protective coatings; Seawater; Self lubrication; Simulation; TC4 alloy; Tetrahedral amorphous carbon; Titanium alloys; Titanium base alloys; Tribology
• ISSN: 0925-9635; 1879-0062
• DOI: 10.1016/j.diamond.2021.108483

The harsh marine environment puts forward higher performance requirements for titanium alloy parts, and it is urgent to develop advanced surface protection technology. In this paper, micro arc oxidation (MAO)/tetrahedral amorphous carbon (ta-C) composite coatings were fabricated via MAO processing and filtered cathodic vacuum arc (FCVA) system on TC4 titanium alloy. The surface morphologies, tribological properties and corrosion resistance in simulated seawater of the coatings were investigated. The results showed that, compared with the monolayer of MAO coating or ta-C film, the MAO/ta-C composite coating still showed porous characteristics and had an improved bonding force. Due to compact oxide ceramic coating of MAO coating and self-lubrication of ta-C film, the MAO/ta-C composite coating had the lowest friction coefficient (0.13) and width of wear scar (356.84 um) in all samples. The lowest corrosion current density (8.321 × 10−9 A/cm2) and highest corrosion potential (−0.012 V) in the simulated seawater solution confirmed the most effective corrosion protection provided by the MAO/ta-C coating. These research results could provide important support for promoting the application of titanium. [Display omitted] •MAO coating, ta-C film and MAO/ta-C composite coating were prepared on Ti substrates.•MAO/ta-C composite coating showed a compact microstructure.•MAO/ta-C composite coating showed best tribological behavior in simulated seawater.•MAO/ta-C composite coating showed excellent corrosion resistance in simulated seawater.