Experimental investigation on suitability of electrolytes for electrochemical micromachining of titanium

Titanium is a potential material for MEMS and biomedical uses owing to its unique high strength to weight ratio and their excellent corrosion resistance property. Machining of titanium by conventional as well as non-conventional methods is a challenge due to its inherent mechanical and chemical properties. Machining of titanium in micro domain is a topic of great research interest. Electrochemical micromachining (EMM) technique could be possible alternative for machining of titanium especially in micro domain. This paper presents systematic investigation of suitability of electrolyte for anodic dissolution of titanium through electrochemical micromachining. In order to investigate the performance of electrolytes, seven different types of electrolytes have been selected. The nature of dissolution of titanium and influence of electrolyte has been studied by machining a set of through micro holes in pure commercial titanium with all these different types of electrolytes. Five electrolytes out of seven have been demonstrated successful anodic dissolution of titanium using EMM process parameters. Out of these five electrolytes, two non-aqueous electrolytes were further evaluated, based on various criteria, i.e. material removal rate, radial overcut and conicity of micro hole. Amongst the two non-aqueous electrolytes, electrolyte with combination of ethylene glycol and sodium bromide has demonstrated excellent results during titanium micromachining by EMM.