Fabrication And Corrosion Properties Of Silane/Carbon Nanotube Composite Film On Stainless Steel Surface

With the widely application of the metal material in various industries, thephenomenon of metal material corrosion cause more and more attention of people. Insea water, the problem of metal material corrosion particularly serious as the highconcentration of chloride ions in sea water. Metal material corrosion mainly fromsome point in the interface,then the corrosion area spend to the whole substratesurface,so that the metal materials lose the original performance.Therefore,thetreatment of metal surface can effectively improve the performance of the substratesurface,prevent the happening of the metal corrosion.The most mature and effective method of metal surface treatment in the lastcentury was the chromic acid salt、phosphate processing on the metal surface, but itwas forbidden as the chromic acid salt、phosphate processing exist some defect,suchas high toxicity and pollute the environment.Therefore, it is badly in need of a simplyoperation and environment friendly metal surface treatment process to replacechromate process. Because of easily filming and environment pollution-free,silanecoupling agent become a hot spot in the field of corrosion.Studies show that metalsurface modified by the silane coating can effectively prevent metal erosion. But thesilane film exist some hole,crack,the protective effect on metal doesn’t last.By addingthe rare earth metal elements or nanoparticles in silane solution can improve theshortcomings of single silane film, so as to improve the corrosion resistance ofcoating.In this paper,we use double-[3-(triethoxy silicon propyl] tetrasulfide (BTESPT)as the research object,by doping carbon nanotubes prepared the MWCNT/BTESPTsilane composite membrane,and study the protective effect for the matrix by electrochemical testing technology. The electrochemical impedance spectroscopytesting show that MWCNT/BTESPT silane composite membrane improve thecorrosion resistance of stainless steel substrate obviously;and the potentiodynamicpolarization curve test show that MWCNT/BTESPT silane composite membranelayer has good compactness and stability, and protect the effect of the metal substrate;The immersion test show that MWCNT/BTESPT silane composite membrane canblock the penetration of corrosive medium, make the protection of the metal substrateeffect is more durable. The addition of carbon nanotubes improve the defects of thecoating obviously, improve the density of the membrane layer, inhibit the corrosionreaction effectively.In order to improve the dispersion of carbon nanotubes, in the experiment we usedopamine coated carbon nanotubes made DA-MWCNT which has good dispersion,adding dopamine modified carbon nanotubes to the BTESPT silane solution, preparedBTESPT/DA-MWCNT silane composite membrane, and via electrochemical testmethod to study the corrosion resistance of the composite membrane layer. Themorphology of dopamine modified carbon nanotubes is studied via transmissionelectron microscope; The potentiodynamic polarization tests show BTESPT/DA-MWCNT composite membrane layer has better compactness, the electrochemicalimpedance spectroscopy test show that composite membrane layer improve thecorrosion resistance of the substrate more effective. The immersion test show that theBTESPT/DA-MWCNT composite membrane layer has better stability and long-termprotection. The addition of dopamine enhanced the adhesion between compositemembrane and metal substrate,so as to improve the corrosion resistance of the matrix.In this paper,we introduce TiO2particles which have photocathodeprotection,then coated with dopamine modified carbon nanotubes,add to the silanesolution, achieved BTESPT/DA-MWCNT/TiO2composite film layer successfully,and the protective effect of composite membrane was studied by electrochemicaltesting technology. The electrochemical impedance spectroscopy test show thatBTESPT/DA-MWCNT/TiO2composite film layer with higher impedance, improve the corrosion resistance of the matrix greatly; The potentiodynamic polarizationcurves show that BTESPT/DA-MWCNT/TiO2composite film layer has bettercompactness; the potential of the metal decrease significantly under the ultravioletlight. The immersion test show that membrane layer prevent the penetration ofcorrosive medium effectively, composite membrane layer have a better protection forthe matrix..