In situ small-angle neutron scattering study of La2Zr2O7 and SrZrO3 ceramics for thermal barrier coatings

Ex and in situ (⩽1300 °C) small-angle neutron scattering (SANS) experiments on annealed layers of air-plasma sprayed La2Zr2O7 and SrZrO3 for thermal barrier coatings are presented. The deposits exposed at 1200 °C up to 100 h showed a stable microstructure of large pores. Medium-size (≈10–50 nm) intragranular pores sinter during the exposure. The in situ SANS revealed that this process starts at 1000 °C. In contrast to La2Zr2O7, the creation of nanopores starting at 900 °C was detected in the SrZrO3 layer. These nanopores began to disappear at 1100 °C.