Effect of HA ratio on the morphology and characteristics of Ti-HA composite coatings on Ti6Al4V-ELI synthesized via mechanical milling

Abstract

Ti-6Al-4V-ELI titanium alloy is useful in biomedical applications due to its mechanical characteristics. To improve properties, alloy surfaces was coated with various methods. In this work, titanium–hydroxyapatite(Ti-HA) composite coatings were deposited on Ti-6Al-4V-ELI through mechanical milling(MM). Coatings’ phase analysis, surface morphology, wear, corrosion, and in vitro performance were examined. The results show that average coating thickness varied between 190 and 305 µm. The substrate has a specific wear rate of 7.22×10⁻⁴ mm³/Nm, while Ti5HA has the lowest rate among composite coatings at 2.7×10⁻⁴ mm³/Nm. Coated surfaces demonstrated better corrosion resistance than bare substrate in electrochemical tests conducted in Ringer's and phosphate buffered saline (PBS) physiological solutions. Ti5HA has the lowest I_corr (0.119 μA/cm²) in Ringer's solution, while Ti10HA has the lowest I_corr (0.245 μA/cm²) in PBS solution. Apatite layer development was seen on all coated surfaces following 7 and 14 days of in vitro experiments.