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.