EXPERIMENTAL INVESTIGATION OF TITANIUM COATING FOR CORROSION RESISTANCE ON STAINLESS STEEL GRADE ASTM 304L AND 316L FOR MEDICAL APPLICATION

Abstract

This research study investigates the surface enhancement of austenitic stainless steels ASTM 304L and 316L for biomedical implant applications through a titanium dioxide (TiO₂) thin film deposited by physical vapor deposition (PVD). This study aims to determine whether a TiO₂ coating can improve corrosion resistance in physiologically relevant environments while maintaining or enhancing key mechanical characteristics required for load-bearing medical components. Uncoated and coated specimens of both grades were evaluated using electrochemical corrosion testing, mechanical testing (hardness and compressive strength), and microstructural/chemical characterization by scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDS). The TiO₂-coated samples exhibited a clear improvement in corrosion behavior compared with the uncoated substrates, indicating a more protective surface and reduced susceptibility to degradation. Mechanical results showed a modest increase in surface hardness and a slight improvement in compressive performance after coating, suggesting that the deposited layer contributed to better surface integrity without compromising bulk response. Among the investigated materials, TiO₂-coated 316L demonstrated superior overall performance relative to TiO₂-coated 304L, consistent with the higher intrinsic corrosion resistance of 316L and the effectiveness of the coating–substrate combination. SEM examination revealed a uniform, dense coating morphology with no visible cracking or delamination, while EDS confirmed the presence and continuity of the TiO₂ layer. These findings support PVD-deposited TiO₂ as a practical route to improve the corrosion resistance and surface performance of stainless steel alloys intended for biomedical implant service.