Investigating the potential of electrical discharge machining for antibacterial coating of titanium implants

摘要

Titanium and titanium alloys are some of the best materials for medical implants owing to their excellent properties including biocompatibility, corrosion resistance and high fatigue strength among others. However, many implants have to be removed after implantation because of bacterial infection. Coating titanium implants with copper or silver has demonstrated antibacterial abilities and has therefore been widely applied to solve this problem. Ion implantation, physical vapour deposition, magnetron sputtering and many other different methods are used to coat these materials. However, until now, there is no method that allows for concurrent machining and coating of the antibacterial layer. Electrical Discharge Machining (EDM) has demonstrated its potential on surface modification owing to the fact that the material from tool electrode and/or powder mixed in dielectric fluid is implanted on the workpiece thereby changing its characteristics. In this study, the suitability of EDM for coating copper and silver on titanium alloy is investigated. Titanium alloy samples are machined using a high precision EDM machine and later analysed for surface quality and chemical composition.