Cold-sprayed AA2024/YSZ metal matrix composite coatings on AZ31B magnesium alloy: microstructure, interfacial adhesion, and tribological performance

Magnesium alloys are increasingly considered for lightweight structural applications in the automotive and aerospace sectors; however, their poor surface durability and limited wear resistance under sliding conditions restrict broader tribological use. In this study, coatings based on the AA2024 and reinforced with yttria-stabilized zirconia were applied to AZ31B magnesium alloy substrates using a low-pressure cold spray process to increase their surface hardness, interfacial adhesion, and tribological behavior. Coatings were produced with yttria-stabilized zirconia content of 5, 10, and 15 wt.% and then tested systematically. Microstructural and elemental analyses confirmed dense coatings with uniform ceramic dispersion and a mechanically interlocked coating–substrate interface. The hardness increased with increasing reinforcement content and reached a maximum value of 216 HV for the coating containing 15 wt.% yttria-stabilized zirconia (YSZ), while the porosity remained as low as 1.5%. Among the investigated compositions, the coating containing 10 wt.% YSZ exhibited the highest adhesion strength of 58.32 MPa, representing improvements of approximately 49.7% and 30.0% compared with the coatings containing 5 and 15 wt.% reinforcement, respectively. This composition also demonstrated superior tribological performance, achieving the lowest specific wear rate of 1.5 × 10−4 mm³/N·m, corresponding to a 78.6% reduction relative to the uncoated substrate. Surface roughness measurements and wear-track morphology further confirmed the enhanced wear stability through lower roughness values (Ra = 2.335 µm, Rq = 2.836 µm) and more uniform wear tracks. Thus, the current results indicate that the 10 wt% of YSZ with AA2024, making them promising for durable lightweight components subjected to sliding contact.