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In the present study, the oxidation resistance of magnesium alloyed with Gd and Ce was investigated. The high‐temperature oxidation resistance of Mg–3.5Gd–xCe (x = 0, 0.2, 0.4, 0.7 and 1.0 wt%) alloys was evaluated at temperatures between 550°C and 650°C. Results indicate that adding less than 0.7 wt% Ce resulted in high oxidation resistance, whereas the Ce addition exceeding 0.7 wt% deteriorated the oxidation resistance. The high oxidation resistance phenomenon is attributed to the formation of compact oxide films primarily composed of MgO, Gd2O3, and a small amount of CeO2 on the surface of Mg–3.5Gd–0.2Ce and Mg–3.5Gd–0.4Ce alloys. These compact oxide films can prevent the matrix from experiencing further oxidation. The deteriorated oxidation resistances of Mg–3.5Gd–0.7Ce and Mg–3.5Gd–1Ce alloys were found to be due to the severe internal oxidation caused by the distributed Mg12Ce phases along the grain boundaries. [ABSTRACT FROM AUTHOR]

This work studied the high-temperature oxidation resistance properties of Mg alloys with Gd and Ca. The oxidation property of Mg-3.5Gd-xCa (x = 0, 0.5, 1.0 and 3.0 wt%) alloys followed parabolic oxidation kinetics at 500 °C. A stable oxide film was formed on the alloy surface and limited further oxidation. The oxide film was composed of Gd2O3, MgO and MgCO3 for Mg-3.5Gd and was mainly CaO and CaCO3 with increasing Ca content for Mg-3.5Gd-xCa alloys. The high oxidation affinity of Ca caused it to be oxidized preferentially and the fast diffusion of Ca in Mg alloys provided a source for the continuous oxidation of Ca at the surface. The parabolic rate constant, grains size and surface roughness of the oxide film increased with the increasing Ca content in Mg-3.5Gd-xCa alloy. The understanding of multi-element alloying on the oxidation behavior of Mg alloy is helpful for the design of multi-element oxidation-resistant Mg alloys. [ABSTRACT FROM AUTHOR]

Oxidation behaviours of Mg- x Y ( x  = 0.5, 1.0, 1.7, 3.7 and 5.5 wt%) alloys were investigated below melting temperature (550–625 °C) in dry air. The corrosion protection properties of the high-temperature oxide films on Mg- x Y alloy matrix in 3.5 wt% NaCl solution were explored. The results showed that oxidation resistance of the Mg-Y alloys increased as a function of addition of Y. Mg-5.5Y alloy exhibited the highest oxidation resistance. The oxidation behaviours of the Mg-Y alloys depended on Y content and the oxidation temperature. Importantly, the oxide films of the Mg-Y alloys were transformed from a loose MgO-rich film to a compact Y 2 O 3 -rich counterpart that suppressed inward diffusion of oxygen and thus prevented further oxidation. Owing to the higher diffusion rate of Mg 2+ ions compared to that of Y 3+ ions in the oxide film, Y 2 O 3 was primarily forming at metal/oxide interface, and MgO was formed at oxide/air interface. Hydrogen evolution tests indicated that the formation of such compact Y 2 O 3 -rich film was beneficial for improving the corrosion resistance of Mg-Y alloys in 3.5 wt% NaCl solutions. However, due to the existence of a large fraction of Mg 24 Y 5 , the protective role of Y 2 O 3 -rich films was deteriorated in oxidized Mg-5.5Y alloy. [ABSTRACT FROM AUTHOR]

This paper studies the effect of the existing state of Y element on the high temperature oxidation resistance of magnesium alloys. Different levels of Al element were added into Mg–2.5Y alloy to obtain different existing state of Y. The oxidation rate of Mg–2.5Y–2.5Al alloy is the highest among Mg–2.5Y, Mg–2.5Y–2.5Al and Mg–2.5Y–4.2Al alloys at 500 °C. An effective and protective Y 2 O 3 /MgO composite oxide film was formed on the surface of Mg–2.5Y alloy after oxidized at 500 °C for 360 min. The results show that the dissolved Y element in the matrix was beneficial to improve the oxidation resistance of magnesium alloys. Once Y element transformed to the high temperature stable Al 2 Y compound, its ability in preventing oxidation would disappear. The formation of Al 2 Y compound severely deteriorated the oxidation resistance of Mg–2.5Y alloy. In addition, the dissolved Al can also cause the rise of oxidation resistance at a certain extent. [ABSTRACT FROM AUTHOR]

The oxidation of water to produce oxygen gas is related to a variety of energy storage systems. Thus, the development of efficient, cheap, durable, and scalable electrocatalysts for oxygen evolution reaction (OER) is of great importance. Here, a high-performance OER catalyst, nitrogen and sulfur codoped graphite foam (NSGF) is reported. This NSGF is prepared from commercial graphite foil and directly applied as an electrocatalytic electrode without using a current collector and a polymeric binder. It exhibits an extremely low overpotential of 0.380 V to reach a current density of 10 mA cm−2 and shows fast kinetics with a small Tafel slope of 96 mV dec−1 in 0.1 m KOH. This electrocatalytic performance is superior or comparable to those of previously reported metal-free OER catalysts. [ABSTRACT FROM AUTHOR]

Oxidation properties of Mg-Y-Sn, Mg-Y and Mg-Sn alloys at 500 °C and corrosion behavior of the oxidized alloys were investigated. The results showed that Mg-Y-Sn and Mg-Y alloys exhibit better oxidation resistance compared with pure Mg and AZ31. Y-enriched oxide films were formed on the surfaces of Mg-Y-Sn and Mg-Y alloys after being oxidized at 500 °C for 6 h and the films are mainly composed of Y 2 O 3 and MgO according to X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analysis. The compact surface oxide film can effectively protect the matrix from oxidizing. Simultaneously, the electrochemical corrosion and immersion tests showed that corrosion resistance of the oxidized Mg-Y-Sn and Mg-Y alloys has been enhanced compared with the initial unoxidized alloys. Y plays a decisive role in improving the protective property of the oxide film. [ABSTRACT FROM AUTHOR]