| For the technical shortcomings that low ionization rate of deposited particles in magnetron sputtering possess and the high-temperature molten drop easily mixed into the deposited particles in multi-arc ion plating,this topic is based on the basic theory of gas discharge in plasma,and constructs dual power pulsed ( DPP ) electric field environment.The gas discharge can be introduced into the glow-arc transition discharge region (strong glow and weak arc ) between the glow discharge and the arc discharge,which has a large electric field strength and current density.In this discharge region,enhancement of the bombardment strength with positive ions on the cathode target surface and the effects of Joule thermal effect inside the cathode target,realize the escape-target mode of collision enhanced heat emission and obtain deposited particles with higher ionization rate and density than that of the magnetron sputtering.At the same time,atomic ionization in the early weak-ionized period can reduce voltage in the later strong-ionized period,and improve the time-averaged deposition rate by decreasing the ratio of ions being attracted back toward the target. Weak-ionized period provides ions bombardment on the surface of the substrate and increases the diffusion energy of the deposited particles in the later strong-ionized period,which provides favorable conditions for preparing films with dense and refined structure.In this paper, several sets of TiN films were prepared mainly at three discharge regions of different volt-ampere characteristics and different peak target current density at DPP electric field mode. Through the study of the microstructure,mechanical,tribological and corrsion resistant properties of films,the following conclusions were drawn:TiN film deposited by DPP electric filed at glow-arc transition region showed lower thick-ness ratio (1.9) ,the approximative time-averaged deposition rate (31nm/min) and higher real-time deposition rate (155.4nm/min ) than that of dc electric filed at glow region,which explained that deposited particles obtained by DPP electric filed at glow-arc transition region had high ionization rate and quantity.Meanwhile,TiN film deposited at glow-arc transition region had surface roughness of 24nm and columnar cross-section structure.lt improved TiN film with a loose columnar structure deposited at glow region,and avoided TiN film with a rough surface (Rms=165nm) at arc region due to high-energy arc discharge easily inducing molten metal particles onto the film surface.TiN film deposited by DPP electric filed at glow-arc transition region had the hardness of 27GPa, the elastic modulus of 309 GPa,the critical load of 19N,the specific wear rate of 1.4425×10-14m3/N·m and the corrosion rate of 0.003mm/a.The deposition of TiN films was investigated by DPP electric field mode at different peak target current densities at the glow-arc transition region.The results showed that:TiN films deposited at a peak current density of 0.87A/cm2 had dense surface and columnar cross-section structure.Through the study of mechanical properties,tribological properties and corrosion resistance,it was also found that the hardness of TiN films increased from 10.2GPa at the current density of 0.27A/cm2 to 29.5GPa at the current density of 0.87A/cm2.At the same time,the wear resistance of films increased,the average coefficient of friction and wear rate were decreased from 0.9,1.383×10-13m3/N·m to 0.67,2.7×10-15m2/N·m,respectively.In addition, corrosion current density and corrosion rate were respectively decreased from 3.4×10-8A/cm2,1.78×10-4mm/a to 1.1 × 10-8A/cm2,5.52×10-5mm/a at current density of 0.87A/cm2. |
PDF Full Text Request