Research On Construction And Performance Of The ZrC_xN_1-x Coating On 316L Stainless Steel

ZrC_xN_1-x coatings were fabricated on 316L stainless steel ?316L SS? by radio-frequency?RF? magnetron sputtering. The microstructures, phase constitution, mechanical properties,corrosion resistance and hemocompatibility of ZrC_xN_1-x 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, hydrophilic-hydrophobic property test, and platelet adhension test. The influence of substrate temperature ?Ts? on the properties of ZrC_xN_1-x coatings was inspected specially.XPS results showed that the content of Zr-O and C-N bond decreased with increasing of the substrate temperature, while the content of Zr-N bond increased gradually and there was no obviously change in the content of Zr-C and C-C bond. XRD results showed that the ZrC_xN_1-x coatings prepared at Ts of 25? and 200? were amorphous. However, the ZrC_xN_1-x coatings were composed of Zr2CN nanocrystals when Ts was 400?. TEM analysis results further confirmed that the nanocrystals were homogeneous spherical grains with the diameter of 4 to 8nm. The ?111? planes could be seen easily, but the ?200? planes almost invisible,which consistented with the XRD results. The ?111? plane could be marked by Fourier transform spectra. The selected area electon diffraction ?SAED? results showed that the electron diffraction pattern of ZrC_xN_1-x coatings were diffraction rings, which indicated that the ZrC_xN_1-x coatings were face-centered cubic structure depending on the camera constant and diffraction ring radius. SEM results showed that a thin coating with a thickness of about 1.08?m was clearly observed over the 316L SS substrate at Ts of 400?, which was extremely dense and homogeneous. The deposition rate in this case was 7.2nm min-1. AFM results showed that the morphology of the coating was influenced by substrate temperature significantly. The surface roughness of the coating was firstly reduced and then raised with increasing of the temperature.Nanoindentation experiment results showed that ZrC_xN_1-x coatings had higher nano-hardness and elastic modulus than 316L SS substrate. The nano-hardness and elastic modulus of ZrC_xN_1-x coatings increased with the increasing deposition temperature. Scratch experiment results showed that ZrC_xN_1-x coatings possessed the strong adhesive strength with substrate when Ts increased to above 200?. Friction and wear test results showed that friction coefficient of the coatings changed rarely under different substrate temperature, which indicated that substrate temperature had no significant effect on tribological characteristics.The wear scar morphology showed that ZrC_xN_1-x coatings deposited at Ts of 200? and 400?had better adhesion to the 316L SS substrate.The potentiodynamic polarization test results showed that the ZrC_xN_1-x coatings deposited at Ts of 200? and 400? possessed better corrosion resistance than those deposited at Ts of 25?. Hydrophilic experiment results showed that surface modification could improve the hydrophilicity of 316L SS substrate. The contact angle of the ZrC_xN_1-x coatings decreased with the increasing of substate temperature. The dispersive component of the surface free energy of ZrC_xN_1-x coatings had no significant changes, which were prepared under different substrate temperatures. With the increasing of substrate temperature, the ratio of polar component of srface free energy increased obviously and the surface tension of ZrC_xN_1-x coatings decreased. Platelet adhesion experiments in vitro resulted that biocompatibility of ZrC_xN_1-x coating was better than 316L SS substrate, When Ts increased, the number and activated pattern of the platelets adhered to the ZrC_xN_1-x coatings were in less.That was owing to effects of surface roughness and surface erengy.