The effect of silica concentration on the tribological properties of micro-arc oxidation coatings on aluminum alloy

To enhance the reliability and durability of the aluminum alloy pistons for automobile engines, the micro-arc oxidation (MAO) and silica lubricating oil additive were introduced to construct a durable anti-friction and wear-resistant route. The Raman spectrum and time-of-flight secondary ion mass spectrometry (TOF-SIMS) were carried out to analyze the effect of silica concentration on the performance of MAO coatings. Results showed a wearable MAO coating with elevated adsorption performance (Si-O, and Si-OH bonds, η-Al 2 O 3 , γ-Al 2 O 3 ) and a complex network structure (Si-O-Al) were prepared on the surface of ZL109. Friction and wear tests illustrated the construction of a friction- and wear-resistant mechanism from a dense layer of MAO coatings, a possible silica third-body coating, and carbonaceous films generated at the friction-pair interface. The friction coefficient was reduced by 54 percent, and the wear loss on the MAO coating was reduced by 90 percent. Surface engineering strategies have shown promising applications in automobile engines.