石墨泡沫/共晶盐复合相变材料的制备及其热物性

Preparation and thermal properties of graphite foam / eutectic salt composite as a phase change energy storage material

为强化二元硝酸共晶盐(NaNO3/KNO3)的导热性能,在共晶盐中添加石墨泡沫制出石墨泡沫/共晶盐复合相变材料;对共晶盐和复合相变材料的相变特性进行差示热分析;对石墨泡沫的导热系数和复合相变材料的有效导热系数进行测定,并用拉曼光谱对复合相变材料进行稳定性分析。结果表明,石墨基复合材料可以用熔融浸渗法制备,且制备样品的稳定性能良好。复合相变材料的相变温度(221.3°C)与共晶盐(222.4°C)相似,其相变潜热与基于复合材料中共晶盐含量的潜热值相近(下降3.74%)。受石墨骨架高热导率的影响,复合相变材料的导热能力明显提高,与纯共晶盐比增加了102倍。

A graphite foam/eutectic salt composite was prepared by the infiltration of the foam by a molten binary eutectic nitrate （ KNO3/NaNO3 ） to improve its thermal conductivity as a phase change energy storage material. The thermal properties and stability of the composite and the eutectic salt were investigated by differential scanning calorimetry and Raman spectroscopy. Results indicate that infiltration using a molten salt is an effective method to prepare the composite, The phase change temperature of the composite （ 221.3 ℃） is similar to that of the salt （222.4 ℃）, and its latent heat is 3.74% lower. The composite has a thermal conductivity 102 times higher than the pure eutectic salt, because of the high thermal conductivity of the graphite. The microstructure of the com- posite remains unchanged after 100 phase change cycles.