Effect of pulse frequency on pulse anodising of AA 1100 aluminium alloy in sulphamic acid

Pulse anodising is a recent method for producing better quality of the oxide film on various alloys of aluminium. Various parameters like 'On' and Off' time, duty cycle and current density have been already studied using sulphamic acid electrolyte. In order to understand the influence of pulse frequency on the anodic oxide film of AA 1100 aluminium alloy in sulphamic acid, low medium and high frequencies were used. The properties of the pulse anodised oxide coatings were evaluated. The effect of pulse frequency at various current densities and duty cycles on the properties of the oxide film such as thickness, hardness, breakdown voltage has been investigated. All the properties of the oxide film formed by pulse anodising increase with increase of pulse frequency. Better quality of the oxide film is obtained at higher pulse frequencies.