A facile one-step electrodeposition method was used to fabricate a hierarchical papillae-covered SHPS on an Al substrate with enhanced corrosion resistance (corrosion inhibition efficiency ~99.96%) and lotus-like self-cleaning effect.

This paper presents a facile, low-cost, one-step approach to fabricate a superhydrophobic surface via electrodepositing aluminum in an ethanol solution containing cerium nitrate hexahydrate and myristic acid. The wettability, morphology and chemical composition of the as-prepared surfaces were characterized by water contact angle (WCA), scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), and Fourier transform infrared spectroscopy (FTIR). The highest WCA of the as-prepared surface after the one-step electrodeposition process reaches 162.1°. Water droplet adhesion force, water stream reflecting, water droplet bouncing, and self-cleaning properties were investigated respectively. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) tests demonstrated that the as-prepared superhydrophobic surface greatly improved the corrosion resistance of the aluminum substrate. The corrosion current density (I_corr) of the as-prepared superhydrophobic surface is smaller by more than 3 orders of magnitude. The presented method is facile, low-cost, and relatively environmentally friendly, and has promising applications in anticorrosion and anticontamination fields.

Synthesized carboxymethyl hydroxypropyl chitosan (CHPCS) containing both carboxymethyl and hydroxypropyl groups was investigated as a corrosion inhibitor for mild steel in 1.0 M HCl solution using weight loss, open circuit potential (OCP), potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. It was found that the compound behaved like a mixed-typed corrosion inhibitor that simultaneously inhibited the anodic dissolution and hydrogen evolution reactions. The compound inhibited corrosion at a low concentration and reached an inhibition efficiency of 95.3% in 1000 ppm (by weight). It was also found that the equivalent circuit model of one time constant was used during EIS analysis. The absorption of CHPCS on the metallic surface obeyed the Langmuir isotherm with a negative value of the free energy of adsorption ΔG. Scanning electron microscopy (SEM) was carried out to corroborate the test results. The potential of zero charge revealed that the corrosion inhibition mechanism involved physisorption and chemisorption processes.