Microstructure, oxidation behaviour and mechanical properties of Fe2O3 doped yttria-partially-stabilized zirconia coatings produced on metallic substrates by electrophoretic deposition

• Yttria-partially-stabilized zirconia were deposited on Fecralloy substrates using electrophoretic deposition.
• α-Fe2O3 powder was used as a sintering dopant.
• The morphology of thermally grown α-alumina scale is different from that of oxidized bare Fecralloy.
• Fe2O3-doped 3Y-PSZ top coats can reduce the TGO scale thickness.
• The early formation of stable α-Al2O3 phase was responsible for the thinner TGO scale.

In this paper, we have reported the use of electrophoretic deposition followed by sintering to produce ytria partically-stabilized zirconia (Y-PSZ) coatings on Fecralloy substrates. With the aim to reduce the sintering temperature, the Fe2O3 was added to Y-PSZ to promote sintering of Y-PSZ coatings. After sintering of the coatings at 1150 °C, the formation of alumina as thermally grown oxide (TGO) scale was observed. The morphology of alumina TGO scale was found to be very different as compared to the TGO scale of oxidized bare Fecralloy substrate. The thickness of TGO scale in Fe2O3 doped 3Y-PSZ coatings was found to decrease with Fe2O3 addition. For both 3 mol.% yttria-partially-stabilized zirconia (3Y-PSZ) and 4.5 mol.% yttria-partially-stabilized zirconia (4.5Y-PSZ) coatings, Young's modulus (Y) and hardness (H) increased with Fe2O3 addition. However, no significant difference in Y and H was observed between 3Y-PSZ and 4.5Y-PSZ coatings over the range of Fe2O3 addition.