Effect Of Surface Etching And Anodic Oxidation On The Corrosion And Antibacterial Properties Of Ti-Cu Alloy

Titanium and titanium alloys are widely used in biomedical materials,especially in orthopedics and dentistry,because of their excellent mechanical and biological properties.Inflammation and infection caused by implants are important problems in the clinical application of titanium alloy.Copper is a trace element in human body,in addition,it is one of the elements with strong antibacterial property in inorganic antibacterial agents.In this paper,Ti-3Cu and Ti-5Cu titanium copper alloy were prepared by adding Cu element into pure titanium.The effects of surface treatment on the physical and chemical properties of titanium copper alloy were studied by scanning electron microscopy(SEM),X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),Vickers hardness tester,contact angle tester and laser confocal microscope.The effects of surface treatment on the corrosion resistance of titanium copper alloy were studied by inductively coupled plasma mass spectrometry and electrochemical workstation.The effect of surface treatment on the antibacterial properties of the alloy was evaluated by plate counting,bacterial dying and bacterial morphology observation.The main research is as follows:The surface selective etching of Ti-3cu and Ti-5cu alloy was carried out with the mixed acid solution of hydrofluoric acid,nitric acid and water at the ratio of 1:2:50.After the etching,the number of the second phase increased significantly,the surface roughness slightly increased,the contact angle decreased,and the hydrophilicity slightly increased.The results of electrochemical experiments showed that the corrosion resistance of the alloy decreased slightly after the surface acid treatment,and the concentration of copper ions dissolved in a short time increased significantly,and the release rate of copper ions became stable after 7 days.After acid etching,the antibacterial rate of ti-3cu alloy(79%)and Ti-5cu alloy(87%)were increased to more than 99%,and the long-term antibacterial performance was maintained.The coloring effect of titanium alloy surface can be changed by adjusting the anodizing voltage and time.The anodizing film of Ti-5cu is generally darker than that of pure titanium.It is found that the oxidation voltage is the main factor affecting the color.Prolonging the anodizing time can deepen the color of the oxide film without changing the primary color.The results of XRD and XPS show that the anodizing treatment can form the oxides of titanium and copper on the surface of the alloy;with the increase of voltage and oxidation time,the roughness becomes larger,the hydrophilicity becomes better,corrosion resistance of alloy increases first and then decreases slightly,and the dissolution concentration of copper ions increases;The results of antibacterial experiment show that anodizing treatment can not give pure titanium antibacterial property,but significantly improve the antibacterial property of titanium copper alloy.After different anodizing treatment,the antibacterial rate of Ti-5cu alloy is more than 99%.Under scanning electron microscope,the bacterial cell wall on the surface of the sample is damaged and the morphology is poor.