Preparation Of NiAlZr Thin Film And Its Electrochemical Corrosion Behavior

In marine chemical industry,energy and other fields,a large number of metal components fail due to corrosion,which not only reduce the service life of equipment,but also cause a huge waste of materials.It is an effective way to prolong the life of materials to strengthen the surface of materials and improve its corrosion resistance.Because of its excellent mechanical properties and corrosion resistance,NiAl intermetallic compound are widely used as corrosion protection coating for marine engineering structure As an advanced surface strengthening technology,magnetron sputtering technology has the advantages of simple equipment,easy control,high efficiency and strong film adhesion.In this paper,considering that the stainless steel substrate is not resistant to chloride ion corrosion in marine environment,which requires corrosion and protection,it is proposed to prepare NiAlZr film on 316L stainless steel substrate by magnetron sputtering technology,and to explore the structure and corrosion resistance of the film prepared under different processes.The main results of this study are as follows:(1)NiAl composite target and Zr target were used as raw materials to prepare NiAlZr films.In order to obtain the best corrosion resistance film,the content of Zr element in the film was adjusted by changing the Zr target power,and the corrosion resistance of the films of different components was obtained.The results show that with the increase of Zr target power,the particles on the film surface gradually become larger and the film becomes rough.In addition,the material phase of the film is mainly composed of crystalline phase and amorphous phase,and the crystallinity of the film gradually increases with the increase of Zr target power,and the crystal phase mainly consists of Al2Zr3,Al3Zrz,AINi and AlNiZr.The charge transfer rate of the film adsorbed intermediates is effectively reduced by the phase structure of the film mixed with amorphous and nanocrystalline.According to the electrochemical impedance curve,dynamic potential polarization curve and its fitting data,when the sputtering power of NiAl composite target is 200W and the sputtering power of Zr target is 50 W,the corrosion resistance of the film is the best.At this time,the corrosion current density is 21.0 nA·cm-2,which is an order of magnitude higher than that of 338.0 nA·cm-2 of 316L stainless steel matrix.(2)The matrix temperature during magnetron sputtering also affects the growth mode,morphology,crystal structure and corrosion resistance of films.The corrosion resistance of films at different sputtering temperatures was investigated by changing the substrate temperature during the sputtering process.The results show that with the increase of the sputtering substrate temperature,the gap between the particles on the film surface became larger.Meanwhile,the crystallinity of the films are also affected by the sputtering temperature.With the increase of the sputtering temperature of the substrate,the crystallinity of the film gradually increases,from the amorphous phase at 200℃ to the three phases of Al32r2,Al2Zr3 and AINi at 400℃.The porosity of sputtering films at different substrate temperatures also varies,and increases with the increase of substrate temperature.The porosity also affects the corrosion resistance of the film.With the increase of the substrate temperature,the porosity of the film gradually increases,and the corrosion resistance of the prepared NiAlZr film gradually weakens.When the substrate temperature is 200℃,the minimum corrosion current of the film is 237.0 nA·cm-2,which is much higher than 338.0 nA·cm-2 of 316L.(3)The sputtering time is also an important factor affecting the corrosion resistance of films,and sputtering time also affects the morphology,crystal structure and porosity of film.The NiAlZr film with different sputtering time were obtained by changing the sputtering time.According to the study,with the increase of sputtering time,the crystallinity of the film is gradually enhanced.When the sputtering time is 30 min,the particles on the surface of the film is gradually minimized,and the columnar structure of the film section is the densest.The crystalline phase of the film was amorphous at 20 min,and the crystallinity of the film was enhanced at 40 min.The crystalline phase mainly consisted of Al3Zr2、Al2Zr3 and AlNi.The films prepared under different sputtering time showed the optimal corrosion resistance at the sputtering time of 30 min.Compared with 316L stainless steel substrate,the corrosion current of the film reached the minimum value of 95.0 nA·cm-2,which was much higher than that of 338.0 nA·cm-2 in 316L.