Nano-Y₂O₃ modified APS Al30Si coatings: Simultaneous β-Si refinement and porosity reduction toward enhanced wear resistance

To improve the wear resistance of Al 30Si coatings, nano-Y₂O₃-reinforced Al 30Si (Y₂O₃/Al-30Si) coatings were fabricated on 6063 aluminum alloy substrates by atmospheric plasma spraying (APS). The effect of nano-Y 2 O 3 addition on the coating was studied in detail. The results show that nano-Y₂O₃ reduced the porosity of the Al 30Si coatings from 8.2 % to 3.1 %. Nano-Y₂O₃ can provide heterogeneous nucleation sites for primary silicon (β-Si) phases, enabling the Y₂O₃/Al-30Si coating to achieve a 57.4 % reduction in β-Si phase size. Correspondingly, the microhardness, elastic modulus and fracture toughness of the coating increased by 11.0 %, 11.2 % and 48.9 %, respectively. Under the present test conditions, the Y₂O₃/Al-30Si coating exhibited a lower coefficient of friction and a 27.2 % reduction in wear volume. Both the Y₂O₃/Al-30Si and Al 30Si coatings exhibited abrasive, oxidative, and fatigue wear mechanisms.