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11.
The aim of this study was to investigate the structure and corrosion resistance of amorphous, amorphous‐crystalline, and crystalline Mg67Zn29Ca4 alloy for biodegradable applications. This paper presents a preparation method and results of the structural characterization and corrosion resistance analysis of the material. Samples were prepared in the form of 3 mm diameter rods. The structure of the alloy was examined with the use of X‐ray diffractometry and scanning electron microscopy. The thermal properties of the samples were examined with differential scanning calorimetry (DSC). Results of DSC analysis were used to determine heat treatment temperatures, allowing to obtain different fractures of crystalline phase in the material. Corrosion resistance of heat‐treated samples was investigated by immersion tests and electrochemical measurements performed in the simulated body fluid. The X‐ray diffraction results confirmed that the prepared Mg67Zn29Ca4 alloy's structure is fully amorphous. After heat treatment, samples with different fractions of amorphous phase in the structure were obtained. Immersion tests of the samples showed that the structure significantly influenced corrosion resistance in examined materials. It should be pointed out, that certain amounts of crystalline phase in amorphous matrix can greatly improve the corrosion resistance of Mg67Zn29Ca4 alloy. 相似文献
12.
In order to meet the growing demand of portable electronic devices and electric vehicles, enhancements in battery performance metrics are required to provide higher energy/power densities and longer cycle lives, especially for anode materials. Alloying anodes, such as Group IVA elements-based materials, are attracting increasing interest as anodes for next-generation high-performance alkali-metal-ion batteries (AMIBs) owing to their extremely high specific capacities, low working voltages, and natural abundance. Nevertheless, alloying-type anodes usually display unsatisfactory cycle life due to their intrinsic violent volumetric and structural changes during the charge–discharge process, causing mechanical fracture and exacerbating side reactions. In order to overcome these challenges, efforts have been made in recent years to manufacture multimetallic anodes that can accommodate the induced strain, thus showing high Coulomb efficiency and long cycle life. Meanwhile, much work has been conducted to understand the details of structural changes and reaction mechanisms taking place by in-situ characterization methodologies. In this paper, we review the various recent developments in multimetallic anode materials for AMIBs and shed light on optimizing the anode materials. Finally, the perspectives and future challenges in achieving the practical applications of multimetallic alloy anodes in high-energy AMIB systems are proposed. 相似文献
13.
《Calphad》2021
Existing alumina extraction and material production methods result in the formation of harmful ammonia gas or ammonia water originating from aluminum nitride (AlN) in dross. Therefore, in this study, aluminum dross was used as a denitration reagent to eliminate nitrogen oxides in flue gas and AlN in dross. Based on the proposed scheme, thermodynamic calculations were performed to investigate the denitrification effect and reduction of aluminum dross in flue gas. The results show that equilibrium concentrations of NO, NO2, and HF in the flue gas were influenced mainly by temperature; their concentrations increased with an increase in the temperature, reaching 4.4 × 10−20, 1.7 × 10−38, and 7.0 × 10−8 g/m3, respectively, at 923 K. The Gibbs free energy corresponding to the reaction of CO2 with Al/AlN in aluminum dross was −377/–120 kJ/mol. HF, originating from the reaction of NaF and water vapor, maintained an extremely low concentration of 6.99 × 10−8 g/m3 at 923 K. These results indicate that aluminum dross processing may clean the flue gas and increase the calorific value while eliminating the hazards of AlN. The results obtained herein will provide theoretical guidance toward new avenues of aluminum dross utilization. 相似文献
14.
Iryna Smokovych Manja Krüger Michael Scheffler 《Journal of the European Ceramic Society》2019,39(13):3634-3642
Silica-based coating systems were developed using polymer derived ceramics (PDCs) technology. Ceramic composites on the base of a SiO2 and SiNO matrix and homogeneously distributed Mo5SiB2, SiB6, Si and B fillers were manufactured. The coating systems have low porosity and provide a high oxidation resistance up to 100 h at 800 °C and 1100 °C in air. The influence of temperature and atmosphere of pyrolysis on the polymer precursor, the volume fraction of filler materials on the chemical composition of compacts as well as their high-temperature oxidation protection was investigated. 相似文献
15.
To improve the electrochemical properties of rare-earth–Mg–Ni-based hydrogen storage alloys, the effects of stoichiometry and Cu-substitution on the phase structure and thermodynamic properties of the ... 相似文献
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《Ceramics International》2020,46(7):8839-8844
In this work, B4C-covered zirconia-toughened alumina (ZTA) particles are prepared and oxidised at 1050 °C for different times (0, 2, 4, and 8 h) in air. The X-ray diffraction and electron probe micro-analysis results show that the covering layer is mainly composed of oxide B2O3 intermetallics, residual B4C particles, and Al18B4O33 whiskers. The scanning electron microscopy results show that the growth of Al18B4O33 whiskers on the ZTA particles enhances with increasing heat preservation time; the optimum holding time is determined to be 8 h Al2O3 in the ZTA particles diffuse into the covering layer and combine with B2O3 to form Al18B4O33 whiskers; the Al18B4O33 whiskers grow via the liquid-solid mechanism. 相似文献
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