On Polishing and Erosion of Aluminum Substrates by a Jet of Alumina Slurry

Polishing of a nominally flat aluminum substrate using a fluid jet, carrying abrasive particles, was investigated. The effects of jet orientation and polishing duration were studied, on a fixed spot on the aluminum substrate. Stylus profilometry was used to examine the final surface along different directions. It was seen that the final erosion contour is strongly dependent on the jet orientation. The surface roughness was found to be dependent on the slurry parameters. On average, the average roughness (Ra) of the aluminum surface was reduced from 430 nm to 139 nm. Best polishing was obtained with the jet orientation of 30°. The process was simulated by using computational fluid dynamics (CFD), and it was concluded that dynamic pressure is the main parameter affecting erosion. Results apply to erosion as well as polishing of metal surfaces.