Microstructure and performance of compositionally graded Ta2O5/Ti thin films on Ti6Al4V alloy deposited by magnetron sputtering

Tantalum pentoxide (Ta2O5) ceramic is a promising material for modifying metal implants due to its superior wear resistance, chemical stability, and biocompatibility. However, the clinical application of Ta2O5 coatings may be limited by inadequate adhesion, resulting from performance mismatches between Ta2O5 coatings and metal substrates. In this study, a Ta2O5/Ti gradient film was developed on the Ti6Al4V titanium alloy substrate using magnetron sputtering, consisting of a Ti bonding layer, four Ta2O5-Ti composite interlayers with graded composition, and a Ta2O5 surface layer. The microstructure and properties of the Ta2O5/Ti gradient films were investigated, with a Ta2O5 monolayer coating as a reference. Results reveal that the gradient layers have higher density, lower surface roughness, diminished residual thermal stress, and improved adhesion, mechanical properties, and wear resistance compared to the Ta2O5 monolayer coating. However, the corrosion resistance of the Ta2O5/Ti gradient layer sample is inferior to that of the Ta2O5 monolayer coating sample, attributed to interphase corrosion between Ta2O5 and Ti within the interlayers. These significant findings offer a promising approach for enhancing the overall performance of Ta2O5 coating on Ti6Al4V titanium alloy surfaces, thereby opening avenues for widespread application in the biomedical industry. [Display omitted] •A Ta2O5/Ti gradient film was prepared on Ti6Al4V titanium alloy using magnetron sputtering.•The microstructure and performance of the Ta2O5/Ti gradient film were compared with those of the Ta2O5 monolayer film.•The Ta2O5/Ti gradient film exhibited lower surface roughness and greater compactness than the Ta2O5 film.•The Ta2O5/Ti gradient film showed better adhesion, mechanical, and tribological properties but lower corrosion resistance.