Tribological Behavior of ZrO2-3Y2O3 Ceramics in Dry Reciprocating Sliding Against SiC Counterparts

In this study, the mechanical and tribological properties of 3 mol. % yttria-stabilized tetragonal ZrO₂ (3Y-TZP) prepared by spark plasma sintering (SPS) were investigated. Nanoindentation revealed a high hardness of 16.51 ± 0.86 GPa and an elastic modulus of 250 ± 8.8 GPa. The low scatter of these values provides strong evidence for a homogeneous, fine-grained microstructure. Vickers microhardness at a 5 N load was 1382 ± 14 and indentation fracture toughness (K IC , Niihara) was 5.2 ± 0.03 MPa·m¹ᐟ², confirming the material’s high mechanical resilience. Dry reciprocating sliding against a SiC counterface exhibited a stable coefficient of friction (COF) of 0.37–0.39, with a slight decrease to 0.37 at 25 N load attributed to the formation of a thin protective tribolayer. Wear track depth increased from ~0.8 µm (5 N) to ~2.8 µm (25 N), and width from ~1.400 µm to ~ 1.600 µm, while the specific wear rate rose only marginally from 9.28 × 10⁻ 8 to 5.05 × 10⁻⁷ mm³/N·m, demonstrating excellent wear resistance. SEM/EDX analysis revealed predominant abrasive wear with microcracking, alongside tribochemical oxidation layers rich in SiO₂ and carbon that contribute to surface protection. Stabilization of the tetragonal phase and a fine-grained microstructure are key factors enabling the superior hardness, elasticity, and tribological performance of 3Y-TZP for applications demanding low friction and high wear resistance.