A study of Fe-Al coating as transition layer on FeCrAl substrate by pack aluminizing

Al2O3 is a promising tritium permeation barrier coating material due to its excellent thermodynamic stability and tritium permeation resistance. However, the thermal mismatch between Al2O3 and FeCrAl alloy will affect the coating performance. Fe-Al coating can act as a transition layer between the Al2O3 coating and FeCrAl alloy which can reduce the difference in thermal expansion coefficient. The process parameters and coating properties of Fe-Al coating prepared on FeCrAl alloy by pack aluminizing have been investigated by energy dispersive spectrometer, scanning electron microscope, electron back scatter diffraction and deuterium permeation experiment. The Fe-Al coating is primarily composed of Fe2Al5 phase. The growth kinetic equation of the Fe-Al coating under different aluminizing temperature below 700 C-degrees and the growth kinetics equation of the Fe-Al coating under different aluminizing time were obtained.