Corrosion protection of a thin aluminium layer deposited on polyester

Abstract

Organosilicon plasma polymer layers were deposited by surface dielectric barrier discharge (DBD) at atmospheric pressure, in an attempt to enhance the corrosion protection of a reflective aluminium (Al) layer applied on a polyester (PET) fabric. A number of tests were carried out to characterize the improvement of corrosion resistance – namely sodium carbonate (Na 2CO 3), water vapor and Kesternich tests – as a function of plasma treatment time, type of carrier gas, admixture of oxygen, amount of hexamethyldisiloxane (HMDSO) precursor supplied to plasma and post-plasma-treatment heating. Moreover, plasma-deposited protective films were characterized by the scanning electron microscopy (SEM), infrared spectroscopy (DRIFT FTIR), and X-ray photoelectron spectroscopy (XPS). While aluminium was consumed in the Na 2CO 3 corrosive solution within a few minutes for the untreated surface, the optimally performing plasma polymerized layers revealed an extraordinary corrosion resistance. Furthermore, the best protective organosilicon coatings showed only a 1–2% absolute reduction of reflection compared to the untreated fabric, over the complete solar spectrum (250–2500 nm).