Preparation And Resistance Corrosion Properties Research Of Fe-based Amorphous Metallic Coating By HVOF Spraying

Iron-based amorphous materials because there was no grain and grain boundary,and has excellent resistance to pitting and crevice corrosion resistance in the Marine environment,which is expected to be as the surface of the key components such as ocean ships,oil drill pipe anti-corrosion coating.Supersonic flame spraying flow of flame temperature is lower,and the particle residence time is short,which is beneficial to make the preparation of amorphous structure and compact structure of amorphous coating.By using supersonic flame spraying technology in the stainless steel substrate surface prepare iron-based amorphous coating,using SEM,TEM,XRD and EDS methods as characterization methods.Testing the microhardness,friction,wear properties and electrochemical corrosion properties of iron-based amorphous coating.Compared with commonly used 304 stainless steel and hard chromium plating,we obtained the following results:(1)The amorphous coating after supersonic flame spraying has higher density and fewer pores.The results of XRD show that the coating is basically amorphous.TEM test identify that the coating structure is composed of some nanocrystalline + amorphous particles.During the spraying process,some nanocrystalline particles appeard in the coating.(2)Above 635 ℃,crystallization phenomenon occurs in iron-based amorphous coating,the crystalline phase,however,is mainly composed of(Fe,Cr)solid solution.During the crystallization process,Cr element enrichment and depletion of Fe elements appeared;Within 635 ℃,amorphous coating microstructure is stable,which can maintain its anti-corrosion and wear-resisting performance.(3)by the method of orthogonal experiment,the preparation of iron base amorphous coating process parameters are optimized and the optimized process parameters are: 26 L/h,kerosene flow oxygen flow 900 L/min,the spray distance is 380 mm,and the feeding amount is 1.2 RPM,optimize the process parameters of preparing coating which has the best micro-hardness and wear resistance,its micro-hardness and wear resistance significantly better than the 304 stainless steel substrate,and close with WC coating.(4)Testing the corrosion resistance of amorphous coating in 3.5% NaCl solution,and compared with 304 stainless steel,hard-chrome plating.The results show that the pitting resistance of iron-based amorphous coating is significantly better than that of 304 stainless steel and electroplating Cr.And the rise of temperature in corrosive medium is immune to its corrosion resistance.(5)Solution pH gain the most popular influence on the formation of amorphous coatingsurface passivation film.In neutral and acidic conditions,the passivation film which can completely formed.However,in alkaline condition,the passivation film is difficult to form,which leading to the poor alkali corrosion resistance.This topic is based on supersonic flame spraying technology,and realize the iron-based amorphous coating rapid and efficient preparation.What’s more,we focuses on the electrochemical corrosion behavior of amorphous coating in the seawater environment,illustrates the protection mechanism of the coating,which will provide theoretical and experimental basis for the development of ocean engineering advanced surface protection technology.