Ternary chloride salt–porous ceramic composite as a high-temperature phase change material

In this study, a ternary salt/porous Si3N4 composite was prepared as a high-temperature shape-stabilized phase change material by pressure impregnation. In this composite, the ternary salt composed of 50 wt% sodium chloride (NaCl), 30 wt% potassium chloride (KCl), and 20 wt% magnesium chloride (MgCl2) was acted as the high-temperature phase change material. A porous Si3N4 ceramic was acted as the skeleton material and heat transfer enhancer. The porosity infiltration ratio of the pores reached 89.19%, demonstrating the good chemical compatibility of Si3N4 with chloride salts. The thermal conductivity of the composite was over six times greater than that of pure ternary salts. The thermal physical properties of the composite were stable even after 300 thermal cycles. The coefficients of thermal conductivity obtained by theoretical analysis and calculation were compared to the experimental values. All the results showed that this composite is a promising candidate as a shape-stabilized high-temperature phase change heat storage material.