Tribological Behavior of Al₂O₃-ZrO₂ + 3Y₂O₃ Composites

This study investigates the tribological behavior of composites based on Al 2 O 3 –ZrO 2 stabilized with 3 mol. % Y 2 O 3 (ZTA – zirconia-toughened alumina), prepared using spark plasma sintering (SPS) technology. The composites were characterized in terms of microstructure, mechanical properties, and wear resistance in a dry ball-on-flat configuration. SEM analysis confirmed a homogeneous and fine-grained microstructure without porosity, with Al 2 O 3 grain sizes of 200–400 nm and ZrO₂ grain sizes of 100–200 nm. Measurements revealed high Vickers hardness (1566.7 ± 133.6 MPa), fracture toughness (6.4 ± 0.29 MPa·m¹ᐟ²), nanoindentation hardness (25.94 ± 2.35 GPa), and Young’s modulus (365.9 ± 18.2 GPa). The coefficient of friction ranged from 0.40 to 0.53 depending on the load, and the specific wear rate was extremely low (4.81 × 10⁻⁷ to 5.08 × 10⁻⁷ mm³/Nm). Analysis of the wear track revealed predominantly abrasive wear without significant fragmentation or delamination. The results demonstrate that optimized microstructure, proper phase stabilization, and a high degree of densification enable the preparation of composites with an excellent combination of hardness, toughness, and tribological resistance. These materials are suitable for demanding applications in industry, energy, and biomedicine.