Surface topography and frictional wear behavior of plasma-sprayed ceria and alumina fused yttria-stabilized zirconia (CAFYZ) coated Al–Si Alloy

This study investigates the tribological performance of the plasma-sprayed Ceria and Alumina Fused Yttria-stabilized Zirconia (CAFYZ) Thermal Barrier Coatings (TBCs) over the Al 20 Cr 20 Ni 60 bond-coated Al-Si alloy for the piston application. The evaluation of surface morphology, thermogravimetric behavior, and tribological behavior for CAFYZ TBCs reveals that the addition of Ceria (CeO 2 ) from 2 to 6 wt% has significantly enhanced the thermal and wear resistance of the CAFYZ TBCs. The 6CAFYZ TBC reduced the crystallite size from 54.44 nm (AFYZ TBC) to 32.34 nm due to the formation of wet edges and improved microstructural integrity. It also enhanced the microhardness by 10.2 times (1298 HV) and the thermal stability by 2.2 times (1370.3 K) compared to the Al-Si alloy. The 6CAFYZ TBC improved the frictional wear resistance of the Al-Si alloy by 6.3 times, achieving a wear rate of 6.59 × 10 −5 g m −1 and a Coefficient of Friction (CoF) of 0.416 at an applied load of 10 N and a sliding velocity of 3 m s −1 . The worn surface analysis of CAFYZ TBCs reveals a transition in dominant wear mechanisms with increasing applied load and sliding velocity. The wear maps showed a clear transition in wear mechanisms from abrasive to adhesive with increasing CeO 2 content. Compared with literature, these coatings achieved lower wear rates and superior stability. The novelty of this work lies in demonstrating the dual improvement in frictional wear resistance and high-temperature durability in CeO 2 modified CAFYZ TBCs.