Microstructure And Properties Of Ti-CU Films Deposited By CO-Sputtering Of HPPMS And DCMS

Nitric oxide(NO)possesses the abilities of inhibition of platelet adhesion and activation,promotion of endothelialization and inhibition of smooth muscle cell proliferation.NO producing materials could improve the biocompatibility of blood contact materials,such as vascular stent,by releasing NO.Cu ions released from biomedical materials can catalyze NO-donor(SNAP)to generate NO to improve the blood compatibility of implanted devices.On the other hand,Titanium(Ti)is becoming increasingly wide used as a biomaterial for cardiovascular appliances,due to its well chemically inert.Based on this,this thesis foused on developing Ti-Cu films with catalytic release of NO.Ti-xCu films with Cu contents ranging from 1.6 to 69.8 at.%were fabricated using a combination of direct current magnetron sputtering(DCMS)and high power impulse magnetron sputtering(HPPMS).To perform a thorough multianalytical characterization,the microstructure and chemical composition of films were systematically analyzed by X-ray diffraction,transmission electron microscopy,and X-ray photoelectron spectroscopy.XRD and HRTEM results showed that,the films with Cu content less than 5 at.%show Ti crystalline phase,the crystalline phases of Ti and Cu formed in the films with Cu contents in the range of 16.3 to 38.4 at.%,while the films above 50.8 at.%Cu present amorphous structure and nanocrystalline.The polarization test results indicate that the Ti-xCu films coated SS with lower Cu content(3.1?-38.4 at.%)possess better corrosion resistance than uncoated SS.However,with the increases of Cu contents,the corrosion resistance decreased and the pure Cu coated SS surface showed the least corrosion resistance.Cu ions release rate detected by ICP-AES shows that the amorphous films with 54.9 at.%or high Cu release significantly higher amounts of Cu ions than the films with Cu contents of less than 38.4 at.%,suggesting that the corrosion behavior of the films significantly affected the Cu release behavior of the films.The platelet adhesion indicated that the Ti-Cu films can inhibit platelet adhesion after cultured with SNAP,and the amount of platelets of the films with higher Cu content is less than the films with lower content.Moreover,the Ti-Cu film with 54.9 at.%Cu exhibited excellent antibacterial abilities,which was attributed to the release of copper ions.It is clear that higher corrosion resistance of films results in the lower copper ion release rate.The Ti-xCu films with controlled copper release displays a promising candidate to deposit on the surfaces of blood contacting materials,such as implanted cardiovascular devices.