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• Corrosion of AZ31 Mg alloy in 0.05 M NaCl solution was examined. • Na 2 MoO 4 inhibitor provides reliable inhibition of AZ31 alloy. • The chemical composition of the molybdate-based protective layer was studied. • Inhibition effect is provided by a surface film of mixed Mo(VI)–Mo(V)–Mo(VI) species. In this work, corrosion inhibition of the AZ31 magnesium alloy was investigated in NaCl solutions containing different amounts of sodium molybdate inhibitor. Electrochemical, hydrogen evolution, microscopic, and spectroscopic experiments were utilized to examine the mechanism of corrosion inhibition by molybdates. The results showed that Na 2 MoO 4 inhibitor provides reliable inhibition at high concentrations (150 mM). Surface examination by Raman and XPS spectroscopy confirmed the formation of a protective surface layer of mixed Mo(VI, V, IV) species. Based on these results, the mechanism of corrosion inhibition of the AZ31 alloy by aqueous molybdates was proposed. [ABSTRACT FROM AUTHOR]

• Visual and instrumental analysis of corrosion of a cooling system of injection molding machines was performed. • Inappropriate selection of materials resulted in galvanic corrosion of the system. • Decomposition of antibacterial agent increased corrosion damage due to release of Cl–. • Mechanism of corrosion failure of a cooling system of injection molding machines was proposed. High-pressure injection molding is an important industrial process, which requires a precise cooling stage. In this work, we analyzed the reasons for the corrosion failure of the cooling circuit of molds in the molding plant. The cooling circuit was inspected visually and collected samples were further analyzed in a laboratory using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The main problems were an improper selection of the antibacterial agent and materials of the cooling circuit. Based on the performed analyses, a possible mechanism of the corrosion attack was proposed and recommendations to decrease the number of corrosion-related failures and services were formulated. [ABSTRACT FROM AUTHOR]

The degradation profile of Mg alloys in biomedical environments can be controlled by applying various types of surface coatings. Phosphate chemical conversion coatings (CaP) and polylactic acid (PLA) biopolymer coatings are biocompatible and promising for the corrosion protection of Mg alloys. The aim of this work was to investigate the physicochemical properties and corrosion performance of inorganic, organic, and mixed inorganic-organic coatings. Three types of surface modification, CaP, PLA, and a combined CaP-PLA coating were obtained on the surface of the magnesium alloy WE43. Scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and infrared spectroscopy were employed to characterize the surface and interfacial morphology, along with the composition of the coatings before and after corrosion experiments. The protective performance of obtained coatings was examined by electrochemical impedance spectroscopy and immersion testing in Hank's solution. Coated samples showed significantly improved corrosion resistance. The values of polarization resistance based on impedance measurements were 164; 8688; 69,410; and 228,369 Ω cm2 for WE43 alloy, CaP, PLA, and CaP-PLA coatings, respectively. The results allowed to propose the mechanism of the coatings growth and their further corrosion degradation. A two-component CaP-PLA coating provided reliable corrosion resistance in Hank's solution for 14 days. [ABSTRACT FROM AUTHOR]