Study on Thick Chromium Film of Special Steel by Arc Ion Plating and Its Properties
In order to extend the service life of gun barrels by improving the wear resistance and high temperature oxidation resistance of their inner walls,it was proposed to apply thick chromium films on special steel substrates by arc ion plating technology.The surface morphology and mechanical proper-ties of the film were studied by scanning electron microscopy(SEM),a nano-indentation instrument,a scratch instrument,a friction and wear testing machine,a energy dispersive spectrometer(EDS)and a X-ray diffractometer(XRD)under different processing parameters.The anti-oxidation behavior of thick chromium films under different oxidation temperature and time was also studied.The results showed that when the bias pressure was-80 V,the deposition temperature was 350℃ and the thick-ness was 50 μm.The surface of the film,uniform and dense,has reduced the wear rate of the special steel substrate to 24.07％and increased its hardness by 5.23 times.After 1 h oxidation at 1 100 ℃,there were only Cr and Cr2O3 characteristic peaks on the surface of the film,and the thickness of the generated oxide layer was only about 6.4 μm with a 17 μm Cr-Fe diffusion layer formed at the joint of the substrate,which helped to improve the firmness of the film layer.With the increase of the oxidation cycle period,the weight of the oxide film on the surface of the film was not obvious,and that of the thick chromium film after 5 h cycle oxidation at 800℃ was 49.293 g/m2,which was only 17.93％of the special steel substrate.The experiments showed that the thick chromium film has good wear resist-ance,and the oxide layer formed at high temperature can effectively inhibit the diffusion of the O ele-ment to the substrate,and can play a certain role in protecting the inner wall of the tube.
arc ion platingbarrelthick chromium filmmechanical characteristicresistance to high temperature oxidation
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