Studies on Mechanical, Biocompatibility and Antibacterial Activity of Plasma Sprayed Nano/Micron Ceramic Bilayered Coatings on Ti–6Al–4V Alloy for Biomedical Application

Ceramic oxides such as alumina and zirconia are used to fabricate dental and orthopedic implants. However, their usage is limited as they fail due to low fracture toughness. To overcome this issue, ceramic coatings on metallic implants is attempted to have a combined effect of ceramics and metallic materials. This paper reports on the microstructure, phase analysis, mechanical properties, osseointegration and antibacterial activity of three different wear-resistant coatings developed on Ti–6Al–4V alloy which is used widely as orthopedic and dental implants. The powders of following compositions, i. Nanostructured Al₂O₃ + 13 wt% TiO₂/μ-TiO₂ BL coating (S1), ii. μ-Al₂O₃ + 13 wt% nanostructured TiO₂/μ-TiO₂ BL coating (S2), iii. Nanostructured Al₂O₃ + 13 wt% TiO₂/μ-YSZ BL coating (S3), were sprayed using atmospheric plasma spray process onto Ti–6Al–4V alloy. The coatings were characterized using X-ray diffraction (XRD), Scanning electron microscope (SEM), Profilometer and gonieometer to determine their phases, microstructure, surface roughness and contact angle. In addition, micro indentation hardness and scratch resistance were also evaluated. Amongst the three coatings, S2 exhibited higher hardness value with higher scratch resistance. The antibacterial activity was studied using colony formation on all three coatings. The antibacterial efficiency of S1 as well as S3 coatings was higher as seen from less number of bacterial colonies on the surface. The results of in-vitro studies on the biocompatibility of nano/micron alumina and zirconia ceramic coatings which were analyzed with hMSC’s, reveals that S1 is cytotoxic with less number of cell attachment when compared to S2 and S3.