Improvement in 316L steel surface features, corrosion and biocompatibility through novel CNT-assisted hydroxyapatite powder mixed-EDM process

Although coating the biomaterials with hydroxyapatite powder (HAp) mixed electro discharge machining (EDM) is required to improve their biological responses, the modified 316L stainless steel shows a low coating adhesion and cracked surface, which is prone to poor corrosion resistance and surface integrity. In addition, inferior biological responses are noticed, since a little amount of HAp is detected in the coating. The primary objective of this study is to assess the CNT reinforced HAp-based coating on a 316L stainless steel to improve the surface features, corrosion and biocompatibility. This study also establishes a link between the process variables and the material�s properties and shows the feasibility of multiple additive mixed EDM method. Following ASTM standard, several surface characterization tools were used to characterize the surface of the modified 316L stainless steel. CNT (0.4 g/l) added to the HAp mixed-EDM method results in a uniform and thin coating of 12.4 µm with shallow craters, nanopores and no cracks. A small corrosion rate of 0.00033 mm per annum is recorded. The presence of carbon incorporated Ca�P-based alloys in the coating ensures a high coating adhesion of 32.6 MPa and a high biocompatibility of more than 95 alive cells. © 2023, The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature.