Plasma sprayed coatings for containment of Cu-Mg-Si metallic phase change material

The performance of Y2O3-stabilized ZrO2 (YSZ), Y2O3, and Al2O3 plasma sprayed coatings are investigated for their ability to prevent attack of Haynes 230 by a near-eutectic Cu-Mg-Si metallic phase change material (PCM) in a closed environment at 820°C. Areas where coatings failed were identified with optical and scanning electron microscopy, while chemical interactions were clarified through elemental mapping using electron microprobe analysis. Despite its susceptibility to reduction by Mg, the Al2O3 coating performed well while the YSZ and Y2O3 coating showed clear signs of failure. Due to a lack of reliable melting in the PCM, these results are attributed to the evolution of gaseous Mg leading to the formation of MgO and MgAl2O4. •Cu-Mg-Si near eutectic PCM is incompatible with Haynes 230 nickel alloy.•YSZ and Y2O3 coatings did not protect Haynes 230 from Cu-Mg-Si near eutectic PCM despite stability of Y2O3 compared to MgO.•Al2O3 protected Haynes 230 from PCM but showed signs of mechanical degradation due to formation of MgAl2O4.