A Research Institute in Osaka, Japan, has developed a new dyeing technology of titanium alloy, which utilizes the EDM process in water.

Titanium alloys are rapidly used in building materials, bicycles, watches and glasses due to their high strength and excellent corrosion resistance. In order to adapt to this kind of use and increase its added value, experts are studying various dyeing methods of titanium alloys, such as atmospheric oxidation, anodic oxidation, chemical oxidation, etc. These methods require special corrosive solution and other processes for dyeing. According to the processing conditions, various dyed surfaces can be obtained at the same time by EDM in water.

The underwater electrical discharge machining (EDM) process is to cut the rough surface of the workpiece properly and finish it. On the one hand, removing the surface layer, on the other hand, dyeing at the same time, the dyeing process which used to require two processes can be reduced to one process. The principle of dyeing by this process is that the exposed metal surface is discharged and the oxides produced by the electrolysis are dyed. Because the number of oxides ultimately determines the dyeing tone, by controlling the average processing voltage, not only all color phases can be formed, but also the color can be changed in any part.