Initial stages of metal-organic chemical-vapor deposition of ZrO2 on a FeCrAl alloy

The initial stages of metal-organic chemical-vapor deposition of ZrO2 on a model FeCrAl alloy was investigated using synchrotron radiation photoelectron spectroscopy, X-ray absorption spectroscopy, scanning Auger microprobe, and time of flight secondary mass spectrometry. The coatings were grown in ultra-high vacuum at 400 °C and 800 °C using the single source precursor zirconium tetra-tert-butoxide. At 400 °C the coatings mainly consist of tetragonal ZrO2 and at 800 °C a mixed ZrO2/Al2O3 layer is formed. The Al metal diffuses from the FeCrAl bulk to the metal/coating interface at 400 °C and to the surface of the coating at 800 °C. The result indicates that the reaction mechanism of the growth process is different at the two investigated temperatures.