Abstract:

To address the issues of low thermal conductivity and leakage in paraffin (PW) phase change materials, porous aluminum metal foams were fabricated as a supporting framework using the ice template method. PW was then infiltrated into these metal foams via vacuum impregnation, resulting in chemically stable phase change composites (PCCs). The morphology, leakage resistance, thermal cycling stability, thermal response performance, and thermal conductivity of the PCCs were evaluated. Results showed that increasing the aluminum framework ratio significantly reduced leakage, enhancing the leakage resistance of the PCCs. The thermal physical properties were further analyzed, revealing that the inclusion of metal foams did not alter the phase transition temperature of PW, with stable melting and solidification peaks at 61 ℃ and 51 ℃, respectively. However, as the aluminum framework ratio increased, the enthalpy of phase transformation of the PCCs decreased. After 50 phase change cycles, the melting and solidification enthalpy values of the PCCs remained largely stable, with PW@30Al samples retaining enthalpy values of 116 J/g and 118 J/g, respectively, demonstrating excellent thermal cycling stability and phase transition reversibility. Additionally, the thermal conductivity of the PCCs improved progressively with a higher aluminum framework ratio, resulting in a faster thermal response. The thermal conductivity of PW@30Al samples increased from 0.2 W/(m·K) for pure PW to 3.1 W/(m·K), representing approximately a 15-fold increase. These findings suggest that the prepared PCCs have significant potential for applications in phase change heat storage and thermal management.

Key words: metal foam, phase change materials, thermal cycle stability, thermal conductivity, phase change heat storage