Electrodeposition of protective organosilane films from a thin layer of precursor solution

Organosilane films were electrochemically deposited onto aluminium alloy AA 2024-T3 for corrosion protection from a thin electrolyte layer (TEL). Compared with those electrodeposited from a bulk solution, silane films electrodeposited from a TEL compartment exhibit improved corrosion performance and enhanced film formation. These phenomena were explained by the increased OH− ions generation rate under a TEL due to the facilitated oxygen diffusion. Silane films electrodeposited at a “critical electrolyte thickness” (CET) provide the best protection resistance, accompanying with the highest deposition current. The negative effect below the CET was interpreted by the insufficient amount of dissolved oxygen in the TEL.

► Thin electrolyte layer (TEL) is used to electrodeposit organosilane films. ► Silane films deposition is facilitated under a TEL. ► Silane films electrodeposited from a TEL exhibit improved corrosion performance. ► These phenomena are believed as a result of faster generation of OH- catalyst.