The behaviour of FeCrAl alloy with a silica-rich ceramic coating SiO2–Al2O3 under high temperature oxidation conditions and thermal shocks

Single- and five-layer protective SiO2–Al2O3 coatings were deposited on an FeCrAl alloy. TEOS and TBA were used as precursors in a silica-rich sol. The deposited coatings improve the alloyʹs resistance to high-temperature oxidation and to thermal shocks (the protection effectiveness is as high as 80%). As a result of diffusion from the core during annealing at 1200 °C, the composition of the sampleʹs surface layer changes whereby the latter becomes enriched in aluminium. The composition of the forming aluminosilicates is situated between mullite and sillimanite (XPS measurements) and they are characterized by a small degree of crystallinity (XRD).