Analysis of machinability of pure-cobalt disc for magnetron deposition using WEDM

Abstract

Cobalt layers prepared by magnetron sputtering are investigated because of their ferromagnetic properties at room temperature for a potential increase in capacity and speed of current memory media. Deposition of magnetically active material is limited by maximum thickness of the used cobalt disc, which was, in this case, set to 3 mm by the device manufacturer. However, the purchased disc had a thickness of 4.3 mm and therefore it was not possible to perform a deposition. For the purpose of halving, we selected an unconventional technology of Wire electrical discharge machining (WEDM), which does not use mechanical energy for material cutting; due to this technology, the workpiece is not affected by mechanical forces. After successful halving of disc, the morphology of machined surface was analyzed using electron microscopy, and subsequently, a detailed analysis of chemical composition energy-dispersive X-ray detector (EDX) was performed in several locations on the sample. Next, the topography was examined and the profile and surface parameters of quality of machined surface were evaluated including a 3D colour-filtered surface image.