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采用直流电弧等离子体方法制备超细纯Mg及Mg-Ti粉体。运用X射线衍射(XRD),透射电子显微镜(TEM),压力成分温度(PCT)方法和TG/DTA技术研究粉体吸放氢前后的相组成、微观结构和吸放氢性能。结果表明,大部分超细Mg和Mg-Ti颗粒呈六角形,颗粒大小在50700nm范围内。根据范特霍夫方程计算由PCT曲线获得的吸氢平台压力,Mg-Ti粉的氢化焓约为67kJ/mol H2,显著高于纯镁粉的氢化焓78.6kJ/mol H2。TG/DTA分析表明,氢化后Mg-Ti粉的放氢起始温度为386°C,低于氢化纯镁粉的放氢温度(423°C)。通过电弧蒸发法直接向Mg中添加Ti而获得的Mg-Ti超细粉体可以显著改善镁的储氢热力学性能。
Ultrafine pure Mg and Mg-Ti powders were prepared by DC arc plasma method. The phase composition, microstructure and hydrogen storage and desorption properties of the powders before and after hydrogen absorption and desorption were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), pressure component temperature (PCT) and TG / DTA techniques. The results show that most of the ultrafine Mg and Mg-Ti particles are hexagonal with a particle size in the range of 50700 nm. The pressure of hydrogen absorption platform obtained from PCT curve was calculated according to van der Hoeff equation. The hydrogenation enthalpy of Mg-Ti powder was about 67 kJ / mol H2, which was significantly higher than the hydrogenation enthalpy of pure magnesium powder of 78.6 kJ / mol H2. TG / DTA analysis showed that the initial hydrogen release temperature of Mg-Ti powder after hydrogenation is 386 ° C, which is lower than that of hydrogenated pure magnesium powder (423 ° C). The superfine Mg-Ti powder obtained by adding Ti directly to Mg by arc evaporation method can remarkably improve the thermodynamic properties of Mg.