Study of Corrosion Effect of Micronal® Phase Change Materials (PCM) with Different Metal Samples

Abstract

Micronal® is a material designed for temperature regulation applications and its performance has been investigated in buildings (Cabeza et al. Energy Buildings 39:113–119, 2007). This wax mixture, classified as organic paraffin, is contained in small vessels with the core PCM and a hard coating (Micronal PCM BASF, Intelligent temperature management for buildings, 2012). Micronal® is an ideal candidate to use in solar applications due to the low melting point (20.9–25.8 °C), high heat fusion (119 kJ/kg) and non-toxic behaviour. In the past, the behaviour of Micronal® between different materials for 722 days has been investigated (Browne et al. Energy Procedia91:113–121, 2016). This experiment has been carried out to study the compatibility of the commercial PCM Micronal® with various common container materials following the ASTM G1-01. The container materials tested were copper, brass, aluminium, stainless steel and mild steel for a period of 1073 days. Stainless steel sample was determined to be the most suitable due to its negligible corrosion rate. Aluminium, copper and brass can encapsulate Micronal; however caution is advised as the maximum corrosion rate was found to be 0.70 mg/cm2year, 2.44 mg/cm2year and 2.26 mg/cm2year, respectively. Furthermore, SEM imaging has been used for a greater insight into the initial stages of corrosion which are not initially visible to the naked eye. From the results, it can be observed that copper, brass and aluminium samples have been corroded by pitting and this is well matched to the gravimetric analysis. No corrosion was observed in stainless steel samples.