Formation Of Dense Oxide Layer Research Articles

Passivation of corrosion product layer on AM50 Mg by corrosion inhibitor

The influence of sodium dodecyl sulfate (SDS) on morphology and chemical composition of corrosion product layer formed on α-Mg matrix and cathodic Al-Mn intermetallic was systematically investigated by using FIB and TEM analysis for the first time to disclose the underlying inhibition mechanism. A porous corrosion bi-layer composed of crystalline MgO and Mg(OH) 2 was observed on both of α-Mg and Al-Mn intermetallic. It was found that a passive inner layer was deposited on α-Mg after immersion in SDS-containing NaCl solution, which can be ascribed to steady-state growth of magnesium and aluminum oxide under the protection of hydrophobic group of SDS. The inhibition mechanism of the inhibitor was mainly associated with formation of dense oxide layer on α-Mg matrix and preferential adsorption of SDS on the corrosion layer deposited on Al-Mn intermetallic.

Oxygen vacancy semiconductor: an additive to improve corrosion protective performance significantly

Semiconductors, based on their unique properties, are widely used in various fields such as in sensors, information and energy technologies, which are usually contact with metallic substances. Among them, oxygen vacancy semiconductors have a wide range of applications such as oxygen sensors, transparent electrodes, and oxygen separation membranes. Herein, the effect of oxygen vacancy semiconductor on facilitating the dense oxide layer formation at its metal interface was demonstrated, which might have a profound effect on many related areas. Corrosion of metal not only causes tremendous economic loss, but also leads to structural failure that brings about catastrophic consequences to human society and environment. In this manuscript, black TiO2 (BT) nanowires, a model of oxygen vacancy semiconductor, were prepared by chemical reduction of white TiO2 (WT) nanowires with NaBH4 and served as an additive in epoxy coatings to protect the metal substrates. The experimental results demonstrate that coatings containing BT nanowires exhibit superior ability to ordinary TiO2 nanowires in the formation of dense oxide layer at the steel/coating interface. Finally, the experimental results were discussed and the mechanism was proposed.

Assessment of tap water quality and corrosion scales from the selected distribution systems in northern Pakistan.

Corrosion deposits formed within drinking water distribution systems deteriorate drinking water quality and resultantly cause public health consequences. In the present study, an attempt was made to investigate the concurrent conditions of corrosion scales and the drinking water quality in selected water supply schemes (WSS) in districts Chitral, Peshawar, and Abbottabad, northern Pakistan. Characterization analyses of the corrosion by-products revealed the presence of α-FeOOH, γ-FeOOH, Fe3O4, and SiO2 as major constituents with different proportions. The constituents of all the representative XRD peaks of Peshawar WSS were found insignificant as compared to other WSS, and the reason could be the variation of source water quality. Well-crystallized particles in SEM images indicated the formation of dense oxide layer on corrosion by-products. A wider asymmetric vibration peak of SiO2 appeared only in Chitral and Abbottabad WSS, which demonstrated higher siltation in the water source. One-way ANOVA analysis showed significant variations in pH, turbidity, TDS, K, Mg, PO4, Cl, and SO4 values, which revealed that these parameters differently contributed to the source water quality. Findings from this study suggested the implementation of proper corrosion prevention measures and the establishment of international collaboration for best corrosion practices, expertise, and developing standards.