Electrochemical etching of stainless steel through laser masking

A new micro patterning process without the need for a mask is proposed in this paper. It is a combination of laser masking and electrochemical etching. In electrochemical etching through laser masking (EELM), selective electrochemical dissolution of stainless steel is achieved in a 2 M sodium nitrite electrolyte. The micro-patterned surface layer of stainless steel is formed by laser marking using an ytterbium pulsed fiber laser. After the laser masking process, the patterned surface of stainless steel is selectively dissolved under an appropriate electrochemical etching condition because the laser-marked area can temporarily act as a barrier during electrochemical etching. The characteristics of the laser-marked surfaces have been investigated by scanning electron microscopy (SEM), x-ray diffractometry (XRD) and x-ray photoelectron spectroscopy (XPS). The polarization curve has been used to evaluate electrochemical dissolution behaviors. The EELM process enables the electrochemical micro-machining of stainless steel without photolithography technology; thus, it can be applied in micro fabrication, micro patterning and surface texturing.