Microstructure and Wear Resistance of Plasma-Sprayed Al2O3-TiO2-CeO2/YSZ Composite Coatings

Yttria-stabilized zirconia(YSZ) was introduced into the Al2O3-TiO2-CeO2 coating prepared by plasma spraying to improve the wear resistance of the coating and prolong the service life of the weathering steel. The nano-agglomerated powder was prepared by mechanical ball milling and spray-drying technology, powder was sprayed on the surface of Q355 steel substrate by atmospheric plasma sparing (APS), the Al2O3-TiO2-CeO2/YSZ composite coating was prepared, and the effects of YSZ on the phase, microstructure, and tribological properties of the composite coating were studied. The results show that nano-agglomerated powders with micron size (average size 55 μm) can be prepared by spray-drying technology, and after high-temperature sintering, the nano-agglomerated powders are denser and form the α-Al2O3 phase. The composite coating prepared by plasma spraying has a bimodal structure, and after adding YSZ, the phases in the coating are mainly α-Al2O3, γ-Al2O3, and t-ZrO2, the grain size is fine, and the porosity is reduced. The specific wear rate is only 4.4 × 10−5 mm3 N−1·m−1, the relative wear resistance is 6.3 times higher than that of the substrate, and the wear mechanism of the coating is mainly slight adhesive wear and abrasive wear, which shows excellent friction and wear properties at room temperature.