High-performance ceramic coatings for additive manufacturing biofunctional titanium alloy by regulating precipitation orientation

Abstract

To prepare high-performance plasma electrolytic oxidation (PEO) coatings with excellent wear resistance and antibacterial activity on biofunctional alloys, Ti-Cu alloy was fabricated by additive manufacturing (AM) technique with controlled crystalline orientation of precipitates to enhance Cu ions release during PEO. In contrast to ingot metallurgical (IM) Ti-Cu alloy with Ti2Cu-(103)-oriented, the Ti2Cu-(110)-oriented in AM-Ti-Cu alloy exhibits a lower work function and inferior corrosion resistance due to its low atomic close-packing. This facilitates the release of Cu ions by promoting valence electron escape from the 4 s energy level during PEO to promote forming a higher content copper oxide (CuO). Subsequent to the PEO treatment, the AM-PEO coating contains more CuO (44.44 wt%) compared to the IM-PEO coating (3.6 wt%), resulting in better corrosion resistance and a lower friction coefficient (0.13 for AM-PEO and 0.34 for IM-PEO). The antibacterial efficacy of AM-PEO coating reached 99.62 %. This study highlights the advantage of regulating precipitate phase orientation in AM processes as an innovative approach to efficiently fabricate functional PEO coatings for alloys.