Mechanical properties of in situ Al2O3 formed Al–Si composite coating via atmospheric plasma spraying

In this study, mechanically alloyed Al–12Si/SiO2 composite powder was deposited onto an aluminum substrate by atmospheric plasma spraying. The composite coating consisting of in situ formed Al2O3 reinforced hypereutectic Al–18Si matrix alloy was achieved. The produced coatings were extensively analyzed with respect to X-ray diffraction (XRD). The XRD patterns of the coatings include Al, Si and Al2O3 phase formation. Mechanical properties of layers were examined by Dynamic Ultra-micro hardness test machine for estimating Young’s modulus due to load–unload sensing analysis. The hardness and Young’s modulus of the composite coatings sprayed at different plasma current and the distance were measured under 200, 400, 600, 800 and 1000 mN of applied peak loads by indentation technique. The effects of spray distance and arc current on the hardness and Young’s modulus have been investigated. Additionally, it was observed that the arc current and spray distance strongly influence the mechanical properties of the coatings.