无机水合盐混合物的热物性研究

Study on the thermal property of inorganic hydrated salt mixture

制备了54种二元混合无机水合盐试样,通过差式扫描量热仪测得重结晶试样的相变温度和相变潜热。结果表明:十水硫酸钠和十水碳酸钠不同配比的无机水合盐混合物,潜热值均低于其组分各自的潜热值,并且有些配比存在严重的过冷和相分离问题;当试样中含有七水硫酸镁时,不能和其他无机水合盐形成良好的二元共晶体,潜热值很低;三水醋酸钠中加入少量的十水碳酸钠可以大幅度地改善三水醋酸钠的过冷问题,相变潜热仍维持在较高值;十水硫酸钠和三水醋酸钠以5∶5的配比制备的二元混合无机水合盐潜热值达297.9J/g,若再加入适当的添加剂可进一步改善其过冷度和相分离问题,可以成为优良的相变材料,应用于相变换热器领域。

54 kinds of binary mixed inorganic hydrated salt samples were prepared.The phase change temperature and phase change latent heat of recrystallization were measured by DSC instrument.The results showeed that the latent heat of inorganic mixtures of Na2SO4·10H2O and Na2CO3·10H2O in different proportions were lower than that of their single component.And some of the proportions had serious problems of undercooling and phase separation.When the sample contains MgSO4·7H2O,it cannot form binary eutectic with other inorganic hydrate salts, and the latent heat value was very low.Adding a small amount of Na2CO3·10H2O in CH3COONa·3H2O can greatly improve the supercooling of CH3COONa·3H2O,and the phase change latent heat was still at a higher value.The latent heat value of binary mixed inorganic hydrate salts of Na2SO4·10H2O and CH3COONa·3H2O prepared by the ratio of 5∶5was 297.9J/g.If they were added in appropriate additives,they can further improve its supercooling and phase separation.Then they can be good phase change materials and were applied to the field of phase change heat exchanger.