Preparation And Properties Of Ti/TiN,Ti/TiN/TiC-Cu Thin Films By Ion Source Assisted HiPIMS

Titanium nitride(TiN)as a kind of hard film,has the advantages of high hardness,good adhesion,and strong decorative.It is used in various tools,such as precision parts and integrated circuits.It has important application value in these fields.However,when the TiN film is deposited by the conventional magnetron sputtering process,the film has structural defects due to the"shading effect"in the sputtering process.In addition,although the hardness of the hard film is high,it is usually at the expense of the toughness of the film,and the poor toughness of the film may cause problems such as cracking or peeling of the film.In view of the above shortcomings of magnetron sputtering and the requirements for the comprehensive performance of the film.In this paper,the design of thin film prepared by ion source assisted high power impulse magnetron sputtering(Hi PIMS).The effects of bias voltage and ion source on the structure and properties of Ti/TiN films were investigated.At the same time,in order to further improve the wear resistance of Ti/TiN films,Ti/TiN/TiC-Cu multilayer films were prepared on the basis of the film system,and the effect of Cu content on the properties of the films was studied.The main finds are as follows:(1)As the bias voltage increases,the energy of the ions increases and the bombardment effect is also enhanced.It is good for reducing the"shading effect"and increasing the density of the film.The porosity and structural defects of the films decrease.When the bias voltage is-200 V,the preferred orientation of the TiN film is(111).At the same time,the grain size of the TiN film is the smallest,compared with other preparation parameters.When the Ti/TiN/TiC-Cu film is prepared,the Cu content increases with the increase of the Cu target current,but the Ti/C atomic ratio does not change much,and the elements are evenly distributed.The results of microstructure analysis show that the surface morphology of Ti/TiN film is“triangle”and“cauliflower-like”,and the density is different.The cross-section morphology is columnar structure.However,the surface morphology of the Ti/TiN/TiC-Cu film is“granular”,because the surface TiC-Cu layer is not a single-phase layer,and the doping of Cu element inhibits the nucleation and growth of the grain.The cross-sectional structure is not a columnar structure.(2)From the point of view of the mechanical properties of the film,regardless of whether there is ion source assisted deposition,when the bias voltage is-200 V,the film has the highest hardness.It can conclude that the hardness of the TiN film can be improved with the proper bias,when it is prepared by physical vapor deposition.At the same time,the assistent of the ion source can further improve the toughness of the film.Therefore,the application of negative bias and ion source assisted deposition can simultaneously improve the hardness and toughness of the TiN film.Ti/TiN/TiC-Cu multilayer films with different Cu contents are prepared on the basis of Ti/TiN films.The proper amount of Cu doped TiC can effectively improve the wear resistance of the film.When the Cu target current is 0.1 A and the Cu content is about 8%,the film has the best wear resistance and the friction coefficient is stable at 0.25.The mechanism of wear are adhesive wear and abrasive wear,and there are a large number of adhesive pits and furrows at the wear scar.(3)The corrosion resistance of the film prepared by physical vapor deposition is closely related to the structure and density of the film.The denser the film,the less the defects,and the longer the corrosion propagation path of the corrosive medium in the film,the less likely it is to contact the substrate and cause corrosion of the substrate.The corrosion resistance of the film can be effectively improved by changing the bias voltage and the ion source.When the bias voltage is-400 V with the ion source assisted Hi PIMS,the corrosion current density of the Ti/TiN film is as low as 7.918×10-8 A/cm~2,and the electrochemical impedance value is as high as 7.5×105?cm~2.The corrosion resistance of the Ti/TiN/TiC-Cu multilayer film to the substrate is not significantly improved,which is related to the film structure and the electrochemical properties of the Cu element.