Preparation Of FeNiCoCrAl High-Entropy Alloy Films By Magnetron Sputtering And The Microstructure And Properties Of The Films

The design concept of high-entropy alloys is based on the preparation of five or more elements in nearly molar ratio.Due to the high mixing entropy,high-entropy alloys tend to form simple solid solution structures.High entropy alloys have good mechanical properties,high temperature resistance,and corrosion resistance.High-entropy alloy has great research and application potential in the field of thin films.In this paper,FeNiCoCrAl high entropy alloy thin films were prepared by RF magnetron sputtering using different sputtering parameters(sputtering time,sputtering power)on the single crystal silicon(100).Annealing experiments(1000°C,5h,10 h,and 15h)were performed on the film to explore the effects of different annealing time on the films.Experiments were performed using field emission electron scanning electron microscopy(FESEM)and spectrometer(EDS),X-ray diffraction(XRD),and nanoindentation to measure the composition,microstructure,and hardness of the high-entropy alloy targets,films,and annealed films.Get the following results:The film composition tends to be uniform with the increase of sputtering power and time,and the film composition is the most close to the equimolar ratio under the sputtering condition of 120 W and 90 min.The films prepared under all conditions are amorphous.The surface of the film obtained by the sputtering is smooth.The film and single-crystal silicon substrate are densely bonded with clear boundaries.The film thickness increases with increasing sputtering power.When the power reaches 120 W,the film thickness reaches a maximum of 300 nm.The hardness of the film decreases with increasing sputtering time and power.At 80 W 30min the hardness reaches a maximum of 212.3Gpa.After annealing,the Al content in the film components increased.The ideal annealing time is 10 h,at this time,the film is still a high entropy alloy film.The films all undergo crystallization transformation,and form a simple solid solution composed of FCC phase and BCC phase.The hardness of the film after annealing was significantly lower than that before.Under the same sputtering conditions,the film hardness increased with the increase of sputtering time,and reached a maximum of 82.55 Gpa at 120 W and 60 min annealing for 15h.