Fig. 7: Surface alteration and microstructure evolution of the LuPO4 after steam corrosion.

SEM images taken at the top surface of the LuPO4 sample post vapor corrosion at 1400 °C for 60 h: a a lower magnification and b a higher magnification image of corroded region (inset is an image of the pristine surface), c a high-resolution image of newly formed microstructure. d SEM image of the cross-section of the coupon post vapor corrosion. e SEM image and EDS maps of the top surface of the sample post-vapor corrosion. f A high-resolution SEM image and EDS maps of the cross-section of the coupon post-vapor corrosion.