Research On The Microstructure And Properties Of TiAlCN Films Deposited With Combining Multi-arc Ion Plating And Magnetron Sputtering Technique

A series of TiAlCN films with different aluminum target currents and pulsed negative biases,TiAIN and TiCN films were deposited on the(100)silicon and AISI 304 stainless steel substrates in an Ar+N2 mixture atmosphere by combining multi-arc ion plating and magnetron sputtering technique.Effects of the aluminum target current and pulsed negative bias on the chemical composition,surface morphology,surface roughness,phase structure,mechanical and corrosion resistance properties of TiAlCN films in a NaCl 3.5 wt.%solution were investigated by means of scan electron microscopy,energy dispersion spectroscopy,X-ray diffraction,X-ray photoelectron spectroscopy,nano-indentation tester and electrochemical workstation.Meanwhile,The relationship between the microstructure and properties of TiAIN,TiCN and TiAlCN films was also compared and analyzed.The results show that:(1)Chemical compositions of the as-deposited TiAlCN films with different aluminum target currents and pulsed negative biases are distributed uniformly.As the aluminum target current and pulsed negative bias increased within a certain range,surface defects of films,such as particles and pinholes,are gradually reduced and well-distributed,improving the surface morphology,refining the structure and increasing the compactness,which enhances the average hardness,elastic modulus and corrosion resistance in a NaCl 3.5 wt.%solution.When the target current and negative bias voltage are 60 A and-200 V,respectively,the TiAlCN film gives rise to the maximum average hardness as well as elastic modulus,and obtaining the favorable corrosion resistance performance in NaCl solution in the light of its fewer surface defects,smooth and dense structure,and finer crystal grains.(2)Compared with the microstructure of TiAlN,TiCN and TiAlCN films,the macroparticles pollution on the surface of TiAIN films is more serious while that of TiCN and TiAlCN films are relatively light,but there are some defects in the TiAIN and TiAlCN films.XRD and XPS analysis results suggest that their composite structure are composed of fcc-TiN type solid solution hard phase and crystal/amorphous soft phase,presenting(111)textured growth,and the TiAlCN film displays slight preferred orientation and fined microstructure in comparison with the TiAIN and TiCN films.(3)Under the same process conditions,the average hardness and elastic modulus of TiAIN,TiCN and TiAlCN films are 29 GPa and 320 GPa(TiAIN),21.6 GPa and 300 GPa(TiCN),36.8 GPa and 410 GPa(TiAlCN),respectively,which are higher than that of SS304(4.8 GPa and 150 GPa)significantly.(4)The potentiodynamic polarization tests show that the corrosion potential of TiAIN,TiCN and TiAICN-coated SS304 shifts to positive values and the corrosion current density decreases sharply.Compared with TiAlN and TiCN films,the optimal TiAlCN film has lower corrosion rate and more excellent corrosion resistance in a NaCl 3.5 wt.%solution with a corrosion current density(icott)of 0.129 ?A.cm-2 and a polarization resistance(Rp)of 430.5 k?.cm2,respectively.(5)Electrochemical impedance spectroscopy(EIS)of films-coated SS304 in a NaCl 3.5 wt.%solution indicate that the penetration behavior of corrosive ions through the diffusion paths formed by the film's defects and the local corrosion process stemming from galvanic couplings(substrate-film)in consequence of the corrosion medium existing at the film/substrate interface are key factors affecting the electrode corrosion reaction kinetic process.In contrast,the TiAlCN film has fewer surface defects,fine crystal grains and the higher film compactness,expressing a better protective effect on the substrate resulted from the higher Rpo and Rct values.