Electrochemical micromachining of NiTi shape memory alloy with ethylene glycol–NaCl electrolyte containing ethanol

• Published in: Journal of manufacturing processes 2020-05, Vol.53, p.223-228
• Main Authors: Ao, Sansan, Li, Kangbai, Liu, Weidong, Qin, Xiangyang, Wang, Tai, Dai, Yu, Luo, Zhen
• Format: Article
• Language: English
• Subjects: Electrochemical micromachining (EMM); NaCl-containing ethylene glycol solution; NiTi shape memory alloy (NiTi SMA)
• ISSN: 1526-6125; 2212-4616
• DOI: 10.1016/j.jmapro.2020.02.019

NiTi shape memory alloys (SMAs) have found several applications in vast areas of engineering. But because of the excellent properties, it is hard to machine NiTi SMAs by traditional machining methods. Electrochemical micromachining (EMM) is a potential processing technology for NiTi SMAs, however previous investigations have not got a desired machining quality. In this study, EMM has been used to fabricate micro-structures on NiTi SMAs with a water-free electrolyte. Ethanol, a typical polar solvent, was added to an ethylene glycol-NaCl electrolyte solution to promote machining quality. The ethanol can adjust the formation of TiCl4 layer thus the formation of oxide film is limited. If ethanol was not added to the electrolyte, there will be excessive TiO2 formed on the surface. When 20 vol.% ethanol was added to the electrolyte solution, improved surface roughness was obtained. But if excessive ethanol is added, the machining accuracy and surface quality will be affected because processed section is more comfortable to be dissolved.