onThis article presents the results obtained for the atmospheric corrosion of copper after 3 years of exposure at different sites within the region of Valparaiso, Chile. Frames were installed with samples at seven sites located close to the coast and inland. They were accompanied by devices to measure atmospheric chloride and sulphur dioxide content and weather stations to obtain data on temperature, humidity, amount of rainfall and wind speed. The results show a correlation between corrosion rate and the environmental and meteorological conditions in the area, and with the morphology and electrochemical properties of the corrosion product formed on the copper surface. The sites gave corrosivity categories of C5, C4, C3 and C2. The behaviour of corrosion rate was modelled using power function models and neural networks. The main corrosion products were cuprite, posnjankite, covelite and atacamite. O (M) Covelite, CuS (t) Cuprite, Cu 2 O (M) Covelite, CuS (t) Valparaíso Cuprite, Cu 2 O (M) Covelite, CuS (M) Atacamite, Cu 2 Cl(OH) 3 (M) Brochantite, Cu 4 (SO 4 )(OH) 6 (t) Atacamite, Cu 2 Cl(OH) 3 (M) Covelite, CuS (M) Cuprite, Cu 2 O (t) Thenardite, Na 2 SO 4 (t) M, major; m, minor; t, traces.

The present study evaluated the activity of extract obtained from the peel of Fuji apples (Malus Domestica) harvested in the region of Valparaiso, Chile, as a potential corrosion inhibitor for carbon steel in a saline medium. The total phenol and flavonoid content in the extract was measured and its main components were identified using HPLC-MS. The inhibition efficiency of the extract was evaluated by mass loss measurements, Tafel polarisation curves and electrochemical impedance spectroscopy, obtaining an inhibition percentage of around 90% at a concentration of 1000 ppm of extract. Adsorption of the extract's components on the surface of the steel followed the Langmuir adsorption isotherm model, implying a physisorption mechanism based on thermodynamic parameters and from the ΔG 0 ads value, which was calculated at -15.16 KJ/mol. SEM was used to verify the presence of an organic layer on the steel, corroborating the adsorption of the organic components from the extract blocking active sites on the steel.

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Atmospheric corrosion of copper, exposed on a tropical island in the South-Central Pacific Ocean, was reported and compared with those of a very similar study at the same site conducted 20 years earlier. The new measurements—taken over three years of exposure, from 2010 to 2013—quantified corrosion by mass loss, characterized corrosion products by X-ray diffraction (DRX) and Raman techniques, observed the attack morphology by Scanning Electron Microscope (SEM), and evaluated the patina resistance using electrochemical techniques. The results showed a copper corrosivity category of C4, and the main copper patina compound, cuprite, was porous, nonhomogeneous, and thin. Electrochemical measurements showed cuprite layer growth as a function of the exposure time, and the morphology did not favor corrosion protection. Finally, when comparing the results to those of a study 22 years previous, the copper corrosion rates increased only slightly, even with increased contaminants associated with growing local populations and continuous tourism on the island.

The effect of microencapsulation of dihydrogen ammonium phosphate (MAP) in the generation of fire-resistant coatings was studied in the presence of tannins extracted from Pinus radiata. MAP was encapsulated to avoid interaction with sodium carbonate (Na2CO3), which, upon contact with fire, generates unwanted gases. Thus, a fireproof (or intumescent) protective film was produced in the presence of the tannins. Microcapsules were polymerized with melamine and characterized by Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), and scanning electron microscopy (SEM)-Energy-Dispersive X-ray Spectroscopy (EDS). The microcapsules were spherical with diameters between 0.7 and 1 µm. The as-produced microcapsules were mixed with tannin extract and the properties of their films were evaluated on wood and structural steel substrates; their fire resistance on medium density fiberboard was also evaluated. Flame resistance tests showed a carbonization index of 26.86% using microcapsules (3% w/w); this is better than commercial coatings. The film properties were similar to commercial coatings, but the adherence was slightly decreased due to agglomeration and also film flexibility.