Chemical and Mechanical Characterization of Thermal-Multilayered Al2O3 Atomic Layer Depositions on AISI 316L Stainless Steel

Abstract

In this work, three different nanometric, multilayered Al2O3 coatings, obtained by alternating two different deposition temperatures, have been applied on AISI 316L stainless steel by atomic layer depositions. The coating morphology has been investigated using atomic force microscopy (AFM) and scanning electron microscopy. Thickness analysis has been performed using AFM and glow discharge optical emission spectrometry (GDOES). In-depth compositional profiles have been performed using GDOES. The corrosion protection has been investigated using polarization curves in aggressive NaCl electrolyte. All variations of the coatings appeared to be adherent to the substrate with thickness in the range of the nominal values. Compositional analysis confirmed the presence of the Al2O3 layers. Vickers indentations used to evaluate coating adhesion showed that all coatings have a good adhesion to the substrate and in particular the amorphous/crystalline 20-nm-thick coating showed almost no sign of coating delamination. All samples show a higher corrosion resistance when compared with bare AISI 316L.