Study On The Preparation And Properties Of Ta Based Coating On 6061 Aluminum Alloy

6061 aluminum alloy with excellent comprehensive performance has been widely used in the field of marine ships.However,its poor corrosion resistance in the harsh marine environment limits its further development in the field of ships.In this paper,in order to improve mechanical properties and anticorrosion performance of 6061 aluminum alloy,Ta_xC_1-x,TaC_xN_1-x and TaSi_xN_1-x coatings were prepraed on its surface by radio-frequency magnetron sputtering.The composition,surface and cross-sectional morphology,and microstructure of the coatings were charactered by means of X-ray photoelectron spectroscopy(XPS),scanning electron microscopy(SEM),atomic force microscope(AFM),multi-functional X-ray diffractometer(XRD)and transmission electron microscope(TEM).The comprehensive mechanical properties of the coatings were characterized by the nanoindentation,scratch and friction test.The anticorrosion performance of the coating was investigated by electrochemical tests.Ta_xC_1-x coatings were prepared under different substrate bias,the influence of substrate bias on theirs microstructure and properties was studied.XPS results indicated that Ta-C bonds could be found in the Ta_xC_1-x coating.SEM images showed that the deposition rate of the Ta_xC_1-x coating decreased with increasing substrate bias.AFM results showd that the surface roughness of the Ta_xC_1-x coating decreased first and then increased with the increase of the substrate bias voltage.XRD results revealed that the Ta_xC_1-x coating with face-centered cubic(FCC)structure was obtained at-150V and it displayed(111)preferential orientation.TEM results show that nanocrystalline TaC spherulites with the size of 3-5nm are distributed in the amorphous.The mechanical properties tests revealed that Ta_xC_1-x coating had best comprehensive mechanical properties under-150V substrate bias.The electrochemical experiment results indicated that Ta_xC_1-x coating displayed the best anticorrosion performance.TaC_xN_1-xcoatings were prepared using various nitrogen-argon volume mixture ratios.The influences of nitrogen-argon volume mixture ratios on their structures,morphologies as well as properties were dicussed.XPS results displayed that the Ta-C and Ta-N bonds mainly existed in TaC_xN_1-x coatings.SEM results indicated that the deposition rate of the coatings decreased with the increase of nitrogen-argon ratio,and the thickness of the coating was uniform and its structure was dense.It could be concluded from AFM results that the TaC_xN_1-xcoating had minimum surface roughness when argon to nitrogen volume mixture ratio was16:4.XRD and TEM results showed that the TaC_xN_1-xcoatings were amorphous.The mechanical tests showed that the TaC_xN_1-x coating had highest nanohardness and elastic modulus,best wear resistance and bonding strength when the argon-nitrogen volume mixture ratio was 16:4.Meanwhile,the TaC_xN_1-x coating had the best corrosion resistance.TaSi_xN_1-x coatings with different Si content were prepared by adjusting the ratio of Si and Ta.XPS results showed that there were Ta-Si bonds and Ta-N bonds in the TaSi_xN_1-x coatings.SEM images showed that the coatings with uniform and dense structures could be observed and the increase of Si/Taresulted in increasing of deposition rate.AFM images indicated that the coating had minimum surface roughness when Si/Tawas 1:4.XRD and TEM figures revealed that the TaSi_xN_1-x coatings were mainly composed of non-crystal phase.The nanohardness of the coating was highest when Si/Tawas 1:4,meanwhile,the coating had the best wear resistance and anticorrosion performance and highest bonding strength.