Corrosion performance of Ti₃SiC₂, Ti₃AlC₂, Ti₂AlC and Cr₂AlC MAX phases in simulated primary water conditions

The response of Ti₃SiC₂, Ti₃AlC₂, Ti₂AlC and Cr₂AlC MAX phases under simulated primary water has been explored for the first time. Samples were tested for 28 days in 300 °C water with the addition of 2 ppm LiOH. The Ti-based MAX phases formed oxides of TiO and TiFeO₃. X-ray diffraction and scanning electron microscopy showed no evidence of a passive Al or Si-based layer forming during testing. A-layer dissolution was observed to cause delamination of the layered structure. In contrast, Cr₂AlC showed little change during autoclave testing, suggesting that a thin passivating chromia layer was formed.