Investigation of the effect of different surface modifications applied to Ti6Al4V alloy on hydroxyapatite coatings produced by EPD method

Titanium (Ti) and its alloys are among the metallic implant materials with high specific strength. Therefore, it is one of the most popular metallic implant materials for biomaterial applications and widely used in orthopedic applications. Due to its high corrosion resistance, the most widely used Ti alloy is Ti6Al4V alloy in the field of biomaterials. Although Ti6Al4V alloy has high corrosion resistance, its strength may decrease under corrosive conditions. The ions released to the surrounding tissue due to the dissolution of Ti and alloying elements can cause very serious problems such as aseptic loosening, loss of color in the tissue, infections, and wounds in the tissues due to the incomplete compatibility of the implant with the bone tissue. In order to eliminate this problem, various surface modifications such as chemically, electrochemically and thermally. and coating processes are applied to Ti6Al4V alloy One of the most frequently applied methods is coating the implant surface with Hydroxyapatite (HA) to increase bioactivity and biocompatibility. However, coating problems may arise due to the inability of ceramic-based coatings to adhere adequately to metallic surfaces In this thesis study, hydroxyapatite with electrophoretic deposition (EPD) method was deposited on Ti6Al4V substrates whose surface properties were changed with different surface modification processes, and the effect of the surface modifications on the HA coating was investigated. For this purpose, in the presented thesis, thermally, chemically, and electrochemically surface modifications in various parameters were carried out on Ti6Al4V samples. Then, surface roughness measurement, contact angle test and SEM/EDS analyzes were performed to determine the effect of surface modification processes. In addition, HA coating on Ti6Al4V alloys with various parameters was performed by EPD method and the most suitable EPD parameter was determined. Then, HA coatings were applied to the samples with various surface modifications in the parameter determined by the EPD method. In order to determine the effect of surface modification process after coating, SEM/EDX analysis and scratch test were performed, and characterization processes were completed. According to the characterization results, it has been determined that the surface modification processes have a positive effect on the quality of the HA coating by changing the roughness and hydrophilicity of the substrate surface.