Weight Loss Corrosion Studies of Al6061 / Quartz Metal Matrix Composites in Sea Water

Abstract

This paper deals with the corrosion characterization of Al6061- quartz particulate metal matrix composites (MMCs). Al6061 alloy is used as matrix. Commercially available alloy is used. Quartz is the wastage obtained after the removal of aluminium from its ore and contains silica, alumina, titanium dioxide and ferric oxide. Being ceramic material quartz remains inert and is hardly affected by the corrosion medium. Quartz particles of size 50-80 microns are used as reinforcement. Experiments were conducted to determine the corrosion rate of the samples in sea water procured from Arabian Sea in malpe, Udupi District, Karnataka. MMC's are prepared according to ASTM standards by liquid melt metallurgy technique using vortex method. Composites containing 2, 4, 6% by weight of Quartz and unreinforced matrix were tested using Arabian sea water at room temperature. Specimens are taken in the form of 20mm x 20mm cylinders. They were exposed to sea water for different intervals of time. Corrosion rates of all samples were calculated using the formula 534W/DAT mpy. The results were computerised and simulation curves were obtained. The composite was found to be more corrosive resistant than matrix alloy. In each test the corrosion resistance of both alloy composites was found to decrease with the exposure time. The decrease in the corrosion rates of composites when compared to that of matrix alloy is due to the physical barrier created by Quartz particles.