Simultaneously improved bio-tribological and biological corrosion properties of taC film coated on Ti6Al4V by sealing with ALD

Abstract

The failure of the implant biomedical materials in the physiological environment mainly depends on the synergistic effect of the corrode and wear. The implant-bone interface is the critical position where the corrosion and wear are often occurred. Most of the work have focused on developing films with anti-corrosion and anti-wear while ignoring the inherent shortcomings in deposition methods. The present paper is therefore focused on investigating the anti-corrosion and bio-tribological performance of the taC composite, in which taC film was firstly fabricated on the Ti6Al4V substrate via hybrid arc ion plating (AIP) system, then a TiO2 layer was deposited on taC surface through atomic layer deposition (ALD). Structural, biological corrosion resistance and bio-tribological properties of the composites were systematically investigated. Results show that the wear resistance of Ti6Al4V is enhanced by the designing taC composite: the friction coefficients of Cr/taC-TiO2 and Ti/taC-TiO2 are decreasing by 6.5 times in relation to the Ti6Al4V substrate; The wear rates of Cr/taC-TiO2 and Ti/taC-TiO2 are 1.7 × 10−6 mm3/Nm and 6.5 × 10−7 mm3/Nm respectively, which are lower than that of Ti6Al4V. Excellent anti-corrosion property was achieved by TiO2 sealed specimen, as evidenced by an order of magnitude higher corrosion potential and notable reduced corrosion current density compared to bare substrate. This is due to the high sealing efficiency of TiO2 layer to reduce the porosity of the taC film when compared with the Cr/taC and Ti/taC film. These composite films on Ti6Al4V substrates, which simultaneously prove an excellent wear resistance and good corrosion resistance, thus could have prospective application in biomedical implants.