Biocompatibility of Ti – Al intermetallic coatings on titanium alloy Ti6Al4V

Abstract

Titanium alloy Ti6Al4V is the most common metal material in orthopaedics. However, it is characterized by high elasticity and bioinertness, which makes it difficult to osseointegrate on its surface and leads to aseptic loosening of the implant, has insufficient corrosion resistance and high wear, leading to the accumulation of metal ions and wear particles in the body of patients. To eliminate these shortcomings, a Ti – Al coating was prepared by electrospark processing of the Ti6Al4V alloy in an equimolar mixture of titanium and aluminum granules. The prepared TiAl coating consists of intermetallic phases: Ti3Al, TiAl, TiAl2, and TiAl3, which have higher tribological properties. Thus, the average value of the friction coefficient of the sample with a TiAl coating was 12% lower, and the reduced wear was 2.36 times less than the original Ti6Al4V alloy one in a simulating body fluid. In addition, the deposition of a TiAl coating on the Ti6Al4V alloy makes it possible to increase the corrosion resistance of its surface. Biomedical studies have shown that the deposition of a TiAl coating on a Ti6Al4V alloy increases the resistance of erythrocytes to the hemolytic agent action. Improving the biological activity of the alloy surface during ESA deposition of TiAl coating leads to normal growth of fibroblasts on it without signs of cytotoxity. Treatment of samples with adhered cell culture by a solution of trypsin-Versen led to a reduction in the density of cells in the coating by 42 %, while in the alloy by 60 %. This indicates a better fibroblast attachment to the surface of the Ti-Al coating, compared to the Ti6Al4V alloy.