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以Al作为相变材料,采用直接氮化法制备出一种核壳结构Al@Al N-Al_2O_3新型高温复合相变蓄热材料。利用X射线粉末衍射仪、扫描电子显微镜、能谱仪、拉曼光谱仪和差示扫描量热分析仪对材料进行表征。进一步研究锂盐助剂种类及反应时间对材料合成的影响,同时对材料的热循环性能进行测定。结果表明:在750℃条件下制备的复合材料达到预期的核壳结构,其相变材料含量64.6%,相变温度为662.3℃,蓄热密度高达326.3 kJ/kg。同时发现Li_2CO_3助剂的加入、反应时间的延长均可促进AlN的合成,从而使核壳结构更加稳定。经过20次热循环后,该材料仍表现出稳定的蓄热性能。
Al as phase change material, a novel high temperature composite phase change thermal storage material Al @ Al N-Al_2O_3 with core-shell structure was prepared by direct nitridation method. The materials were characterized by X-ray powder diffraction, scanning electron microscopy, energy dispersive spectroscopy, Raman spectroscopy and differential scanning calorimetry. The effects of lithium salt additives and reaction time on the material synthesis were further studied, and the thermal cycling properties of the materials were also measured. The results show that the composite prepared at 750 ℃ has the expected core-shell structure with phase change material content of 64.6%, phase transition temperature of 662.3 ℃ and heat storage density of 326.3 kJ / kg. At the same time, it was found that the addition of Li 2 CO 3 additive and the prolongation of reaction time can promote the synthesis of AlN, so that the core-shell structure is more stable. After 20 thermal cycles, the material still exhibits stable heat storage.