Parameter optimization of electrophoretically deposited graphene oxide coating on the frictional characteristics of AISI 52100 alloy steel

Abstract

Wear-resistant coatings help to extend the life of materials by improving their tribological properties. Among the various coating methods, electrophoretic deposition (EPD) is a simpler, low cost and effective coating method in which the charged particles in colloidal suspension are deposited on the substrate. Graphene oxide (GO) has been coated by different deposition methods, but the optimization of EPD coating factors for improving frictional characteristics has been studied limitedly. This work aims to optimize various parameters of EPD coating such as voltage, deposition time, concentration and sintering temperature for a lower tribological response. Experiments were conducted using the L16 orthogonal array created by the Taguchi optimization method. After sintering the samples, tribological tests were done using a Pin-on-Disc apparatus. The influence of coating parameters and the optimum combination of the factors for a lower coefficient of friction (COF) was found and experimentally validated. A crack density study has been done to study the influence of porosity on frictional characteristics. Results showed that the COF of the optimum GO-coated substrate (0.152) was lowered by 71.33% while comparing with the COF of uncoated substrate (0.53) under the same test conditions.