Study On The Preparation Technology And Corrosion Resistance Of Nano-Boron Nitride Doped Silane Film

Silanization of metal surface has the advantages of less process and no pollution.As a new environmental protection process,silanization has become a research hotspot in the field of metal protection.However,single silane film has defects such as surface cracks,pores and so on,which cannot play a long-term protective effect on metals.Hexagonal boron nitride(BN)has been widely used in industrial applications because of its high insulation and permeability resistance,and has become a favorable material for anticorrosion applications.The purpose of this paper is to modify silane films by doping hexagonal boron nitide to make up for the defects of silane films and enhance the corrosion resistance of metals.The film formation and corrosion resistance mechanism of silane composite films are also discussed.Dopamine-modified boron nitride(mBN)was obtained by non-covalent modification of dopamine,and mBN/BTESPT composite film was prepared by bifunctional silane bis-[?-(triethoxy silicon)-propyl]-tetrasulfide(BTESPT)as film forming agent.The mBN was characterized by infrared spectroscopy,thermogravimetric analysis and scanning electron microscopy(SEM).The results showed that PDA was successfully modified on the surface of the BN.The silane films were characterized by infrared spectrum analysis and scanning electron microscopy(SEM).The results show that there is mBN on the surface of mBN/BTESPT silane films,and the doping of mBN increases the thickness of the silane films.The contact angle test and binding force test were used to characterize the properties of silane films.It was found that MBN enhanced the hydrophobicity of silane films,and the two kinds of silane films had better binding force.The corrosion resistance of mBN/BTESPT silane membrane is better than that of single silane membrane by electrochemical test,neutral salt spray test and acid-base corrosion test.The electrical conductivity of monofilane ?-glycidyl ether oxypropyl trimethoxy silane(KH560)hydrolysis was measured.The results showed that the electrical conductivity increased firstly and then decreased with the hydrolysis time.The optimum preparation parameters of KH560 silane film on the surface of 40 Cr steel were determined by two orthogonal experiments.mBN/KH560 silane films were prepared by doping KH560 silane with mBN.The results showed that mBN adhered to the surface of KH560 silane films by SEM observation and infrared spectroscopy.The silane films were characterized by contact Angle test and binding force test.It was found that the composite silane films had better hydrophobicity,and both kinds of silane films showed good binding force.Through electrochemical test,neutral salt spray test and acid-base corrosion test,it was found that doping mBN enhanced the corrosion resistance of KH560 silane film.mBN/KH560/BTESPT bilayer silane composite films were prepared by two-step film forming method.Micro-particles were found in mBN/KH560/BTESPT silane films by SEM characterization,and the film thickness increased compared with that of single silane films.The properties of silane films were characterized by contact angle test and binding force test.The results show that the two kinds of silane films reach hydrophobic surface,and the silane films have good binding force.The chemical bonds and element morphologies of silane films were analyzed by infrared spectroscopy and X-ray photoelectron spectroscopy(XPS).The results show that mBN and silane are covalent bonded.The corrosion resistance of KH560/BTESPT silane film was characterized by Tafel polarization curve,neutral salt spray test and acid-base corrosion test.It was found that the corrosion resistance of KH560/BTESPT silane film was better than that of single silane film,and the double-layer film modified by mBN could play a better corrosion protection effect on metal.