Wear characterization of functionally graded Al–SiC composite coatings produced by Friction Surfacing

Aluminium–SiC functionally graded composite coatings were produced using a Friction Surfacing multi-layering approach. SiC particles with a median size of 118.8, 37.4 and 12.3 μm were packed inside AA6082-T6 aluminium rods and used as consumables. AA2024-T3 plates were used as substrates. By performing successive fully overlapped depositions with increasing SiC concentration or particle size, a gradient along the coating thickness was produced. Several strategies to incorporate SiC particles were investi, as well as, their influence on coating properties, particle distribution and homogeneity. Results indicate that the smaller particles were more easily embedded in the aluminium matrix during deposition. The multi-layer coating presents a composition gradient, as SiC area fraction gradually increases from 5% to 30%. The use of reinforcements enabled to increase coating surface hardness in 30%, while the wear rate was reduced in 13%. Coating wear occurs by delamination, based on the combination of abrasive and adhesive mechanisms. Evidence of three-body abrasive wear was found in the reinforced coatings due to the detachment of SiC particles.