Unravelling the roles of ceramic composition and content in electrochemical corrosion of cold-sprayed Ti matrix composite coatings

● Wear- and corrosion-resistant titanium matrix composite coatings were fabricated via cold spraying. ● The electrochemical performance of the coatings is determined by the ceramic composition and content, together with coating microstructure. ● Electrically conductive WC particles promote localized galvanic corrosion of the coatings. ● Al 2 O 3 has no influence on the electrochemical performance of the coatings. ● Corrosion models were proposed for ceramic-reinforced titanium matrix composite coatings. Titanium matrix composite coatings with enhanced wear and corrosion resistance were fabricated by cold spraying with varying contents of single-phase WC, dual-phase WC, or Al 2 O 3 as reinforcement. The electrochemical performance, corrosion products, phase composition, surface and cross-sectional microstructure of composite coatings were compared after corrosion tests. Results show that the galvanic corrosion between anodic W 2 C phase and Ti leads to severe damage to the coating surface and the coupling of WC phase and Ti causes the corrosion of Ti. Al 2 O 3 has no influence on electrochemical corrosion behavior. The corrosion mechanism models of cold-sprayed titanium matrix composite coatings were proposed.