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以硅酸钠和硝酸为原料,采用溶胶-凝胶法制备了硝酸钠/氧化硅(NaNO3/SiO2)复合定形相变材料,分析了材料的组成、物相、热稳定性和相变性能.结果表明,原位生成的NaNO3作为相变物质分散在载体SiO2的多孔网络结构中形成定形相变材料,仅是NaNO3与SiO2的物理复合,制备和焙烧过程中都没有产生新物质.材料在低于600℃时具有良好的热稳定性,融熔热和结晶热分别为144.1和142.6 k J/kg,融熔和结晶温度分别为302.3和301.2℃.经100次热循环后,材料的相变热和相变温度基本保持不变.
NaNO3 / SiO2 composite phase change materials were prepared by sol-gel method using sodium silicate and nitric acid as raw materials. The composition, phase, thermal stability and phase transition properties of the materials were analyzed. The results show that the NaNO3 generated in situ is dispersed in the porous network structure of SiO2 carrier to form a phase change material, which is only a physical composite of NaNO3 and SiO2, and no new material is produced during the preparation and calcination. It has good thermal stability at 600 ℃, and the heat of fusion and crystallization are 144.1 and 142.6 kJ / kg respectively, and the melting and crystallization temperatures are 302.3 and 301.2 ℃, respectively. After 100 cycles of thermal cycling, the phase transformation Heat and phase transition temperature remained unchanged.