Al@AlN-Al2O3高温复合相变蓄热材料的制备与性能研究

PREPARATION AND RESEARCH OF Al@AlN-Al_2O_3 COMPOSITE PHASE CHANGE THERMAL STORAGE MATERIAL AT HIGH TEMPERATURE

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。

A novel core-shell Al@AlN-A12O3 composite phase change thermal storage material at high temperature was prepared with Al as PCM by a direct reaction between Al and nitrogen. The products were studied by X-ray powder diffractometer, scanning electron microscope, energy dispersive spectrometer, Raman spectrometer analyzer and differential scanning calorimeter. The effects of the type of lithium and reaction time on the synthesis of AlN shell were further investigated. The thermal cycling performance of the materials was determined at the same time.The results showed that the composite material reache the expected core shell at 750℃. The percentage content of A1 is about 64.6% and the heat storage density of such materials could reach to 326.3 kJ/kg with a phase change temperature of 662.3 ℃. It＇s also found that Li2CO3 as an additive could obviously accelerate the formation of AIN than LiNO3, and relative long reaction time is favorable for improving the stability of the core-shell structure of the Al@AlN-A12O3 materials. After 20 thermal cycles, the materials still show good thermal stability.