Effects of In-Situ Synthesis Nanoscale Ag/Ag₂MoO₄ Composite Lubricants on Tribological Properties of YSZ Coatings

In virtue of the intrinsic defects (micro- cracks and pores) of yttria-stabilized zirconia (YSZ) coatings fabricated by air plasma spraying, Ag/Ag₂MoO₄ were in-situ synthesized inside the pure YSZ coatings via vacuum impregnation process coupled with hydrothermal reaction. Results show that the generated Ag/Ag₂MoO₄ were spherical-like nanoparticles with the diameter of 78~111nm and YSZ-Ag/Ag₂MoO₄ composite coatings were successfully fabricated. The results of tribological tests present that the composite coatings possessed a lower friction coefficient and an extremely lower wear rate compared with the pure YSZ coatings at room temperature (RT) and 600 ℃. The excellent lubricating and were-resistant properties were ascribed to the formation of the smooth lubricating layers on the worn surfaces of composite coatings, thus effectively restraining the brittle fracture and abrasive wear of pure YSZ coatings.