Nanomechanical properties and microstructure of ZrO2/Al2O3 plasma sprayed coatings

Nanocomposite coatings were prepared by atmospheric plasma spraying process using the Yttria-stabilized zirconia (YSZ) power mixed 5 wt.% nano-Al2O3. The mechanical properties of the nanocomposite coatings were studied by nanoindentation and the microstructures were studied by SEM and TEM. Compared to the microcomposite coatings prepared with YSZ powers without nano-Al2O3, the nanocomposite coatings can better tolerate applied loads and has higher hardness and elastic modulus values, better elastic recovery, and excellent microstructure. Associated with the investigation of the microstructure, the nano-Al2O3 is shown to play a major role in the grain refinement, densification, and microcrack formation, and be beneficial for better mechanical properties of the coatings.