Influence of Fe powders replacing Cu powders on the thermal and mechanical properties of aluminate cementitious thermal energy storage materials at high temperature

Cost-effective thermal energy storage materials are vital to the application of solar thermal power plants . One focus of this paper is improving thermal and mechanical properties of the thermal energy storage materials; the second focus lies in reducing the investment cost. On the basis of aluminate cementitious composites with 1   wt% nano-SiO 2 , 1   wt% nano-Cu and 15   wt% Cu powders, we introduced different wt% (0, 5, 10, and 15) of Fe powders to gradually replace 15   wt% Cu powders. The samples were heated at 105, 350, and 900   °C, respectively. As a result, when the content of Fe powders substitution was 10   wt%, volume heat capacity, thermal conductivity and compressive strength of the composites after heat-treatment at 900   °C were up to 2.38   MJ   m −3   K −1 , 1.45   W   m −1   K −1 , and 73.8   MPa respectively, which were 26.6%, 26.1%, and 24.0% higher than those of the composites with 15   wt% Cu powders. At the same time, the investment of the composites with 10   wt% Fe powders substitution was reduced almost 62.0%, compared with that of the composites with 15   wt% Cu powders. In addition, XRD and MIP were employed to characteristic the mineral phases and the pore structures of the aluminate cementitious composites, respectively.