The phase stability and thermophysical properties of InFeO3(ZnO)m (m = 2, 3, 4, 5)

The phase stability and thermophysical properties of InFeO3(ZnO)m (m = 2, 3, 4, 5) compounds were investigated, which are a general family of homologous layered compounds with general formula InFeO3(ZnO)m (m = 1–19). InFeO3(ZnO)m (m = 2, 3, 4, 5) ceramics were synthesized using cold pressing followed by solid-state sintering. They revealed an excellent thermal stability after annealing at 1450 °C for 48 h. No phase transformation occurred during heating to 1400 °C. InFeO3(ZnO)3 exhibited a thermal conductivity of 1.38 W m−1 K−1 at 1000 °C, which is about 30% lower than that of 8 wt.% yttria stabilized zirconia (8YSZ) thermal barrier coatings. The thermal expansion coefficients (TECs) of InFeO3(ZnO)m bulk ceramics were in a range of (10.97 ± 0.33) × 10−6 K−1 to (11.46 ± 0.35) × 10−6 K−1 at 900 °C, which are comparable to those of 8YSZ ceramics.