Preparation And Properties Of TiO₂/Cu-（AlSiTiCrNbV）N Composite Coatings

Titanium alloy is widely used in aerospace,navigation and other fields because of its high strength,excellent high temperature resistance and corrosion resistance.Although titanium alloy has many excellent properties,its wear resistance is poor compared with stainless steel and other alloys.In addition,the biological pollution of marine environment to titanium alloy also accelerates the loss of titanium alloy.In this paper,TiO₂/Cu-（AlSiTiCrNbV）N composite coating was prepared on the surface of titanium alloy by micro arc oxidation and magnetron sputtering.The surface morphology of the composite coating was observed by scanning electron microscope（SEM）,the element composition of the coating was analyzed by energy dispersive spectroscopy（EDS）,the composition of the coating was characterized by X-ray photoelectron spectroscopy（XPS）,and the porosity of the coating was calculated by image software.The wear resistance,corrosion resistance and antibacterial properties of the coating in simulated seawater environment were studied.The main conclusions are as follows:（1）Cu-（AlSiTiCrNbV）N films with Cu target power of 0,12,16 and 20 W were deposited on the surface of titanium alloy by magnetron sputtering.With the increase of Cu target power,the Cu content and thickness of films increase.The element of AlSiTiCrNbV high entropy alloy target mainly exist in the film in the form of nitrides.When the sputtering power of Cu target is 16 W,the friction coefficient of the film in simulated seawater reduces to 0.2,the friction coefficient curve fluctuates gently,and the wear width is 278.12μm.Compared with the titanium alloy and Cu films deposited at sputtering power of 0,12 and 20 W,the wear resistance of the Cu film deposited at sputtering power of 16 W is significantly improved.The（AlSiTiCrNbV）N film improves the corrosion resistance of titanium alloy,but with the addition of Cu in the film,its corrosion resistance decreases.When the sputtering power of Cu target is 16 W,the antibacterial properties of the films prepared on the surface of titanium alloy show that the absorbance of the bacterial solution is low,the bacterial survival rate is low and the bacterial adhesion is less.（2）TiO₂/Cu-（AlSiTiCrNbV）N composite coatings were prepared by adding 0,5,10,15 g/L copper sulfate into micro arc oxidation electrolyte.With the increase of copper sulfate concentration,the surface micropores of composite coating are reduced,showing a smoother and denser morphology,and the porosity is reduced.The composite coating prepared by adding 5g/L copper sulfate into the electrolyte has excellent wear resistance in simulated seawater,small wear width and depth;The corrosion resistance of the composite coating is significantly higher than that of single Cu-（AlSiTiCrNbV）N film,and the corrosion current density is reduced by 3 orders of magnitude;Because the TiO₂ layer and Cu-（AlSiTiCrNbV）N film contain Cu element,TiO₂/Cu-（AlSiTiCrNbV）N composite coating has good antibacterial property.（3）The deposition of Ti N,Cr N and Cu-（AlSiTiCrNbV）N film on the surface of TiO₂ layer that prepared by micro arc oxidation was compared.It was found that Ti N on TiO₂/Ti N composite coating is attached to TiO₂ layer in the form of sheet,and the microporous part of TiO₂ layer is covered by Ti N film;The pore diameter of TiO₂/Cr N composite coating is different,and part of Cr N is accumulated on the surface of TiO₂ layer as large particles;The TiO₂/Cu-（AlSiTiCrNbV）N composite coating has a flat and smooth surface,less holes,a low porosity and less particle accumulations.TiO₂/Cu-（AlSiTiCrNbV）N composite coating has lower friction coefficient and better wear resistance than TiO₂/Ti N composite coating and TiO₂/Cr N composite coating;The corrosion resistance of TiO₂/Ti N,TiO₂/Cr N and TiO₂/Cu-（AlSiTiCrNbV）N composite coatings is better than that of single Ti N,Cr N and Cu-（AlSiTiCrNbV）N coatings,and the corrosion resistance of TiO₂/Cr N composite coating is the best;For a single coating,Cu-（AlSiTiCrNbV）N has better antibacterial property than Ti N and Cr N coatings.The antibacterial property of TiO₂/Cu-（AlSiTiCrNbV）N composite coating is better than TiO₂/Ti N and TiO₂/Cr N composite coatings.