Powder mixed electrical discharge texturing of AISI 316 for biomedical applications: an in-depth comparative study of various dielectrics and electrode materials

Biomedical materials have extreme popularity in osseo-integration applications, particularly for orthopaedic and dentistry implants, owing to their unique specialties. However, the implants of AISI 316L stainless steel (SS) material cannot fulfil the need of the application mentioned above due to poor bond adhesion between bone and natural tissues of the environment. Therefore, it is necessary to perform surface treatment before experiencing it in any living cell. Surface modification is an approach that can increase the surface morphology of the material and make it a bio-friendly material. Various methods can modify surfaces; among them, electric discharge texturing (EDT) is a newly developed approach. EDT is the next step of electric discharge machining and provides excellent roughness results when there is an urgency to study the surface asperities of the material. However, the role of additives during EDT of SS 316L material is not examined yet. Thereof, the main intention of this work is to apply the concept of powder mixed EDT to assess the surface roughness (SR) against four input variables, including powder type (alumina, graphite, silicon carbide), electrode type (aluminium, copper, brass), dielectric type (kerosene oil, transformer oil, canola oil), and pulse time ratio (0.5, 1.0, 1.5). Taguchi L9 orthogonal design has been operated to analyse the impact of machine inputs on the output response. The results showed that kerosene oil is better than other dielectrics in providing the lowest values of SR. At a 0.5 value of pulse time ratio, an excellent surface finish is attained when brass is selected as electrode material. The results were witnessed through evidence collected by an optical microscope, scanning electron microscope, and surface profilometry. In the end, the optimal setting has been suggested and validated through confirmation trials.