A comprehensive review of the materials degradation phenomena in solid-liquid phase change materials for thermal energy storage

Phase Change Materials (PCMs) employ latent heat property for storage and management of thermal energy in various applications. In order to ensure efficient performances of PCMs, their compositional compatibility in terms of corrosiveness on container/encapsulation materials is as important as thermal characteristic. This compatibility is usually determined with respect to factors such as exposure time and temperature, flow and non-flow condition, and static and dynamic conditions. The basic understanding of how corrosion/degradation mechanisms proceed on PCMs’ container/encapsulation materials provides for extended serviceability of thermal management or storage systems. Therefore, this paper has reviewed the corrosion/degradation mechanisms of container/encapsulation materials subjected to organic, inorganic and metallic PCMs exposure under static-isothermal, static-thermal cycling, dynamic-isothermal conditions. Common materials for containers and encapsulation are Carbon Steels (CS), Copper (CP), Aluminium (AL) and Stainless Steels (SS) where CS and CP were mostly degraded due to PCMs’ corrosive attack. Aluminium is mostly faced with pitting based on galvanic effect of impurities contained while the challenge mostly encountered with stainless steels is alloying element depletion, especially chromium depletion which can change the thermal properties of the fluid. However, SS have shown to be the most resistant to corrosive attacks. Another material with potential for use as container material is SiC, a corrosion resistant material. Generally, degree of corrosion for these materials are in the order of SiC<SS<AL<CP<CS. Overview of methods so far investigated for combating corrosive attacks of PCMs on container/encapsulation materials have been highlighted and recommendations on areas of further research are provided.