Research On The Superhard Self-lubrication And Non-adhered To Aluminum Properties Of TiMo(C)N Composite Coating Prepared By Multi-arc Ion Plating

In recent years,the state has vigorously promoted the manufacturing mode of energy saving and environmental protection,and the concept of modern advanced manufacturing technology has gradually formed.CNC machining technology is developing rapidly in the direction of high precision,high efficiency,dry cutting and green.Traditional hard coatings(such as Ti N,Cr N,Ti Al N,etc.)cannot meet the machining requirements of most materials,such as titanium and its alloy,aluminum and its alloy,nickel base superalloy,hardened steel,stainless steel,etc.TiMoN coating has received extensive attention due to its high hardness and better self-lubricating properties.Doping C can further improve the hardness and self-lubricating properties of the coating.In this work,a series of Ti Mo(C)N coatings were deposited on the surface of high-speed-steel substrates by multi-arc ion plating.By adjusting the pulse bias duty cycle,C₂H₂ flow rate and deposition pressure,Ti Mo(C)N coatings with different properties were obtained.Generally,the duty cycle has a great influence on the surface morphology of the coating.In this experiment,the increase of duty cycle not only optimized the surface quality,but also reduced the coefficient of friction(COF)and the wear rate of TiMoCN coatings.Due to the combined lubricating effect of MoO₃ and sp2 C,the coating obtains the lowest COF of 0.18and specific wear rate 1.0×10^-6 mm³/N·m,shows better self-lubricating effect and the best wear resistance when the duty cycle is 80%.However,the duty cycle has little effect on the hardness of TiMoCN coatings.The variation of duty cycle resulting the hardness changing in the range of 30.2-33.1 GPa.After that,in order to obtain the coating with super-hard self-lubricating and non-adhered to Al properties,the C₂H₂ flow rate was adjusted firstly.With the increase of C₂H₂ flow rate,the hardness of the coating increases slightly at first,and then decreases significantly,and the highest hardness of 30.7 GPa is obtained at C₂H₂ flow rate 50 sccm.With the increase of C₂H₂flow rate,the non-adhered Al property of the coating increased.When the C₂H₂ flow rate increases to 75 sccm,Ti Mo(C)N coating shows better non-adhered to Al property.In contrast,a large amount of Al is adhered on the surface of TiMoN coating.Although MoO₃ and sp2 C have lubricating effect,the lubricating effect of MoO₃ cannot play an effective role in the non-adhered to Al performance of the coating,and the high content of sp2 C can effectively improve the non-adhered Al performance of the coating.With the increase of C₂H₂ flow rate,the graphitization degree of amorphous carbon in the coating increases,then elevating the content of sp2 C,and resulting a better non-adhered Al property.Then we adjust the deposition pressure to obtain the superhigh hardness coating.With the increase of deposition pressure,the hardness of the coating decreases,while the COF and the specific wear rate increases.Due to the grain boundary effect of the nanocomposite structure,the strengthening effect of Ti₂N hard phase and the solid solution effect of C andMoatoms,TiMoCN coating shows super-high hardness of 40.1 GPa at deposition pressure of 0.04-0.05Pa.And the coating also perform low friction coefficient of 0.33,lowest wear rate of 0.53×10^-6 mm³/N·m,and better self-lubricating effect.