Sandwich-like electrochemical micromachining of micro-dimples using a porous metal cathode

Micro-dimples are widely used in tribology as a surface texture to improve the interfacial performance of mechanical components, thus reducing friction, wear, vibration, and noise. Electrochemical micromachining is a popular method for fabricating micro-dimples. Sandwich-like electrochemical micromachining can be used to produce micro-dimples, but these tend to be shallow because of the gas bubbles and insoluble electrolytic products that accumulate on the enclosed electrochemical reaction unit. In this study, a porous metal cathode is used to remove the electrolytic products and generate deep micro-dimples by using an open reaction unit instead of an enclosed one. The experimental results show that a porous metal cathode can remove gas bubbles and some nonconductive insoluble electrolytic products, leading to deep micro-dimples. Moreover, the smaller the pore size of the metal cathode, the better the dimensional uniformity of the micro-dimples.