Study of the influence of voltage variation on the surface texturing of Ti-6Al-4V using electrolytic plasma technique for orthopaedic implant applications

Osseointegration is a process consisting of the formation of bone tissue on the implant surface, so that the osseointegration process occurs, a surface with surface roughness (Ra) is required in isotropic microtopography with a size of 1-100 nm. The plasma treatment can be done to reach the Ra parameter. This study aims to discuss the treatment of Plasma Electrolytic Process (PEP) with the principle of physiochemical erosion using electrolytic cells on Ti-6Al-4V alloy implants, to form a plasma layer in the form of spark discharge and Vapour Gas Envelope (VGE). Samples made of Ti-6Al-4V are tested with several parameters including different electrolytes and different applied voltages are investigated, and the results of the formation of VGE which influences the surface characterization are evaluated. The results show that the process of PEP with electrolyte consist of 50% H₃PO₄ + 10% NaClO4 + 1% HF and 10% ethylene glycol + 2% NH4F at a voltage of 90-130 V produces VGE and non- homogeneous spark discharge resulting in a surface with microporous structures with increasing surface roughness and micro-hardness indicating the formation of an oxide layer.