New advances on maskless electrochemical texturing (MECT) for tribological purposes

Surface texturing can be applied to improve tribological performance of mechanical contacts, in particular in the case of lubricated systems. The purpose of this work was to improve an alternative method for surface texturing based on electrochemical dissolution without previous masking of the workpiece named maskless electrochemical texturing (MECT). Electrochemical dissolution combines high speed, good reproducibility and high cost-benefit ratio, which are important factors when an industrial application of surface texturing is pursued. The use of electrical discharge machining (EDM) for the manufacturing of the MECT tools enabled different microtexture patterns to be produced. The cathodic tool was an AISI 430 ferritic stainless steel plate containing a pattern of microholes and covered with an insulating paint layer. The effect of important parameters such as the gap between electrodes, the applied voltage and the texturing time were evaluated. Different texturing patterns containing dots, trace-dots and chevrons were successfully obtained using a NaCl solution electrolyte. Tribological tests textured surfaces under starved liquid lubrication showed friction and wear reduction, when compared with a smooth surface.