Effect of Fe2O3 doping on sintering of yttria-stabilized zirconia

This paper reports the effect of Fe2O3 doping on the densification and grain growth in yttria-stabilized zirconia (YSZ) during sintering at 1150 °C for 2 h. Fe2O3 doped 3 mol% YSZ (3YSZ) and 8 mol% YSZ (8YSZ) coatings were produced using electrophoretic deposition (EPD). For 0.5 mol% Fe2O3 doping, both 3YSZ and 8YSZ coatings during sintering at 1150 °C has similar densification. However, a significant grain growth occurred in 8YSZ during sintering, whereas grain size remains almost constant in 3YSZ. XRD results suggest that Fe2O3 addition substitutionally and interstitially dissolved into the lattice of 3YSZ and 8YSZ. In addition, colour of 3YSZ and 8YSZ changes differently with doping of Fe2O3. A Fe3+ ion interstitial diffusion mechanism is proposed to explain the densification and grain growth behaviour in the Fe2O3 doped 3YSZ and 8YSZ. A retard grain growth observed in the Fe2O3 doped 3YSZ is attributed to Fe3+ segregation at grain boundary.