Study On Structure And Tribocorrosion Property Of TiSiCN Coating On Titanium By Arc Ion Plating

Ti6Al4V alloy is widely applied in the fields of navigation and ocean exploration due to its excellent combination of low density,high strength-to-weight ratio and excellent resistance to corrosion.However,the low hardness and poor wear resistance limit its application,and it is urgent to develop protective coating material combinng self-lubrication and wear-corrosion resistance to meet fast-developing naval vessel,bathyscaph and marine engineering equipment.TiSiN coating and the Ti₃SiC₂ MAX phase have been extensively studied.TiSiN coating exhibits super-high hardness,outstanding wear resistance.The Ti₃SiC₂ with particular lamellar structure is widely considered to have a similar structure with the graphite,and it exhibits excellent self-lubricating tribological properties under low-micrometer-scale frictional condition.In this study,the TiSiCN coatings are deposited on Ti6Al4 V by arc ion plating.The influence of the carbon contents on structure and tribocorrosion behavior is studied.In addition,the effects of bias voltage on microstructure and tribocorrosion property of the TiSiCN coating and the failure mechanism of the coating in corrosive medium are studied.1.The coatings consist of TiN,TiC and Ti（C,N）nanocrystallites,amorphous Si3N4,SiC and a little amorphous carbon.2.The coating with the carbon concentration of 11.9 at.% exhibits maximum hardness of 39.8 GPa and the best tribocorrosion resistance,which is attributed to the special nanocomposite structure,and the lower friction coefficient of the TiSiCN coating associated with the graphitization effect during sliding in atmosphere.3.The results of tribocorrosion indicate that the volume loss of TiSiCN coatings is ascribed to main wear loss and a little corrosion loss,and the synergy between wear and corrosion is a key factor in degenerating the TiSiCN coating.4.As the bias voltage increases,the TiSiCN coating shows a nanocystallite/amorphous structure,whereas the phase constitution and grain size change slightly,and the hardness and tribocorrsoion property also change correspondingly.5.When the bias voltage is-100 V,the coating has a composite structure of typical nanocystallite/amorphous,and a small amount of MAX phase of Ti₃SiC₂.6.The protection potential applied on the coating can effectively prevent the electrochemical corrosion of the coating.However,the applied protection potential will accelerate the degradation of the coating when the channel formed between the surface of the wear track and substrate.