Synthesis, infrared stealth and corrosion resistance of organically modified silicate–polyaniline/carbon black hybrid coatings

Hybrid coatings based on organically modified silicate–polyaniline/carbon black (Ormosil-PANI/CB) were synthesized through a sol–gel technique with different carbon black (10–30 wt%) and PANI/CB (10–30 wt%) contents. These hybrid films were deposited via spin coating onto an aluminum alloy in order to improve the corrosion protection and to act as infrared stealth coatings. The effects induced by the PANI/CB composites on the chain dynamic, thermal properties, infrared stealth, and anticorrosion performances of the coated samples were investigated. The rotating-frame spin–lattice relaxation times and scale of the spin–diffusion path length indicated that the configuration of the hybrid films was highly cross-linked and dense. Thermal properties of these Ormosil-PANI/CB hybrids have been improved over the pure Ormosil analyzed by thermal gravimetric analysis (TGA). The thermal extinction of the hybrid coatings increased with the increase in the carbon black and PANI/CB content. Potentio-dynamic and salt-spray analysis revealed that the hybrid films provided an exceptional barrier and corrosion protection in comparison with untreated aluminum alloy substrates.

Figures (a) and (b) shows the mid-wave (3–5 μm) and long-wave infrared (8–12 μm) thermal images of PE and Ormosil-PANI/CB(10)-30 hybrid mixed with PE. The surface temperature (maximum and average) decreased significantly for Ormosil-PANI/CB(10)-30 composite (572 and 325 °C) in comparison with the value of PE (700 and 496 °C). Figure (c) shows optical micrograph results before and after 168 h of salt-spray tests for the AA 2024-T3 and Ormosil-PANI/CB(10)-30 coating on AA 2024-T3. The corrosion of aluminum alloy was significantly inhibited by the presence of Ormosil-PANI/CB hybrid coatings.Figure optionsDownload as PowerPoint slide