Preparation And Characterization Of Zr-C Coatings With Different Carbon Contents

ZrC coatings were deposited on 316 L stainless steel(316L SS)by radio-frequency(RF)magnetron sputtering technology in the paper.The microstructures,phase constitution,mechanical properties,corrosion resistance and hemocompatibility of ZrC coatings were systematically investigated by X-ray photoelectron spectroscopy(XPS),X-ray diffraction(XRD),transmission electron microscope(TEM),scanning electron microscope(SEM),atomic force microscopy(AFM),nanoindentation techniques,scratch test,wear test,electrochemical measurments,and platelet adhesion test.The effects of carbon content on the microstructure and properties and mechanism of performance changing of ZrC coatings were explored.SEM results showed that the thickness of ZrC coating was about between 0.40?m and 0.50?m.The surface topography showed that the surface of the ZrC coatings were smooth without defects such as dents and scratches.The XRD results showed that 316 L SS and ZrC coatings were face-centered cubic structures.In addition,the ZrC grain has preferred orientation growth of(111).Besides,the ZrC grains refined gradually with increasing of the carbon content.The TEM results showed that the ZrC coatings exhibited in the form of spherocrystal and(111)lattice fringes were most frequently observed,which consistented to the results of XRD.The XPS results showed that there were Zr and C elements and a little O and N elements in the ZrC coatings.The content of C-C bond increased and arrangement of extranuclear electronic of Zr tended to be Zr3 d in Zr-O bond with increasing of C content in the analysis of C1 s and Zr3 d.AFM results showed that the morphology of the coating was influenced by the carbon content.The surface roughness of the coating was firstly reduced and then raised with increasing of the carbon content.Nano-indentation results showed that the nanohardness of 316 L SS could be improved by the deposition of ZrC coatings effectively.In addition,the nanohardness of 316 L SS increased with the increasing of C content which attributed to the refinement of ZrC grain.Scratch experiment results showed that ZrC coatings possessed strong adhesion strength when the C content was 18% and 24%.The adhesion strength decreased when C content increased.The abrasive resistance test showed the abrasive resistance of 316 L SS could be improved by the deposition of ZrC coatings effectively.The electrochemical corrosion experiment indicated that the ZrC coatings could improve the corrosion resistance of 316 L SS effectively.Platelet adhesion experiments and dynamic blood coagulation experiment in vitro indicated that biocompatibility of ZrC coatings was better than 316 L SS substrate.The number and activated pattern of the platelets adhered to the ZrC coatings were in the growth with the higher C content.That was owing to effects of surface roughness.