Study On Water Vapor Corrosion And High Temperature Tribological Properties Of Ti₂ALN Thin Films

The Ti2AlN thin films with MAX phase structure have great application potential in wear resistance,life extension and corrosion protection due to its good mechanical properties and excellent high temperature oxidation resistance.Although there have been many research achievements in thin film preparation,high temperature corrosion,room temperature friction and wear,etc.,related research on N2 flow rate,high temperature and high pressure water vapor corrosion,high temperature friction and wear is still not perfect.Therefore,in this paper,Ti2AlN thin films were prepared by magnetron sputtering and vacuum annealing,the effect of N2 flow on the thin film structure and basic mechanical properties was analyzed,and the thin film’s resistance to water vapor corrosion and high temperature friction and wear were studied.Show:(1)Under vacuum annealing conditions at 750℃,the prepared thin films can form Ti2AlN when the N2 flow rate is 4,5,and 6 sccm;where the N2 flow rate is 4,5 sccm,the Ti2AIN thin films have the(002)preferred orientation,while the latter the orientation degree is higher,and the Ti2AlN thin film has no preferred orientation when the N2.flow rate is 6 sccm.The(002)preferentially oriented thin films have similar surface morphology and minimum roughness,but the hardness and elastic modulus of the thin film without preferred orientation are higher.(2)The Ti2AlN thin films undergoes oxidative corrosion in a water vapor environment of 360℃ and 18.6MPa.As the corrosion time increases,the oxidative corrosion continues to increase,and the corrosion weight increases linearly with time.The corrosion rate of the(002)preferentially oriented thin films are relatively slow,and they are mainly uniform corrosion,and the corrosion products are mainly TiO2.The corrosion weight gain rate of the unoriented thin film is relatively fast.In addition to uniform corrosion,pitting is also produced.The corrosion product is still mainly TiO2.(3)The coefficient of friction of Ti2AlN thin films decrease with the increase of ambient temperature,and the specific wear rate increases with the increase of ambient temperature before 600℃.When the temperature reaches 600℃,the specific wear rate decreases.The coefficient of friction of the(002)preferentially oriented thin films are relatively lower in each temperature section,while the specific wear rate of the thin film without preferred orientation is the lowest in each temperature section.In addition,the wear of the Ti2AlN thin films are mainly attributable to abrasive wear at low temperatures and to oxidative wear at high temperatures.