An investigation on erosion behavior of nanostructured 7YSZ coatings at elevated temperature

• An in-house constructed elevated temperature erosion test facility was developed.
• The electrical properties of as-sprayed and eroded specimens were measured by impedance spectroscopy.
• The erosion mechanism is dominated by the spalling of the sprayed splats caused by the propagation of microcracks.

In this paper, an in-house constructed elevated temperature erosion test facility was developed to conduct the particle erosion tests of nanostructured 7YSZ coating with particles of different mass. The electrical properties of as-sprayed and eroded specimens were evaluated by impedance spectroscopy. The constant phase element parameter nc and Ac corresponding to the microcracks decreased and increased with increasing particle mass, respectively. This is due to the fact that the nucleation, propagation and coalescence of microcracks along the overlapped splat interfaces between lamellae decrease the homogeneity of the coating. The development of microcracks results in the spalling of the sprayed splats, which accounts for the material removal during the erosion process.