Polyacrylamide （PAM） film was electrosynthesized on mild steel by cyclic voltammetry using Ce （IV） salt-oxalic acid as supporting electrolyte. Polymerization was initiated by a free radical that was formed by the ...Polyacrylamide （PAM） film was electrosynthesized on mild steel by cyclic voltammetry using Ce （IV） salt-oxalic acid as supporting electrolyte. Polymerization was initiated by a free radical that was formed by the fast reaction of oxalic acid and Ce （IV）. The electrolysis of the reaction solution resulted in regeneration of Ce （IV）, which could oxidize oxalic acid to produce radicals. The effect of temperature on the yield of electroinitiated polymerization was performed. The potential sweep rates were changed to achieve the polymer film with different thickness. Protective properties of the PAM film for corrosion of mild steel in 1 M NaCI aqueous solution were investigated by potentiodynamic polarization curves and electrochemical impedance spectroscopy （EIS）. The structure of PAM film on mild steel was investigated by using physicochemical methods such as elemental analysis of C, H, N, physical chemical methods and FTIR spectrometer. The influence of scan repetition and scan rate on the formation of polymer film was studied at a current density of 1 mA/cm2. The results of these studies reveal that the corrosion resistance of the PAM-coated mild steel was significantly higher and the corrosion rate was considerably lower than that of uncoated steel. The PAM film was formed with lower sweep rate leading to more positive shift of corrosion potential and greater charge transfer resistance, reflecting higher inhibition for corrosion of the mild steel.展开更多
For a long time, chromate incorporated conversion coatings have been drawn special attention in corrosion protection of aircraft-used aluminum alloys. However, ever-increasing environmental pressures requires that non...For a long time, chromate incorporated conversion coatings have been drawn special attention in corrosion protection of aircraft-used aluminum alloys. However, ever-increasing environmental pressures requires that non-chromate conversion coatings be developed because of the detrimental carcinogenic effects of the chromate compounds. In recent years, the sol-gel coatings doped with inhibitors were developed to replace chromate conversion coatings, and showed real promise; A sol-gel coating was prepared and its anti-corrosion behavior was investigated using the potentiodynamic scanning （PDS） and the electrochemical impedance spectroscopy （EIS）. It is found that the sol-gel coating obtained by the hydrolysis and condensation of 3-glycidoxypropyltrimethoxysilane （GPTMS） and tetramethoxysilane （TMOS） is prone to form defects if cured at the room temperature, whereas if cured at a higher temperature （100℃）, these flaws can be avoided. Furthermore, it can be seen that addition of anti-foam agents and surfactants will reduce the faults if cured at the room temperature. Effects of the corrosion inhibitors, CeCl3 and mercaptobenzothiazole （MBT）, in the sol-gel coatings on 2024-T3 aluminum alloy were also investigated. Results show that the corrosion resistance of the sol-gel coatings containing CeCl3 proves to be better than that of the pure and MBT added sol-gel coatings by the electrochemical methods.展开更多
文摘Polyacrylamide （PAM） film was electrosynthesized on mild steel by cyclic voltammetry using Ce （IV） salt-oxalic acid as supporting electrolyte. Polymerization was initiated by a free radical that was formed by the fast reaction of oxalic acid and Ce （IV）. The electrolysis of the reaction solution resulted in regeneration of Ce （IV）, which could oxidize oxalic acid to produce radicals. The effect of temperature on the yield of electroinitiated polymerization was performed. The potential sweep rates were changed to achieve the polymer film with different thickness. Protective properties of the PAM film for corrosion of mild steel in 1 M NaCI aqueous solution were investigated by potentiodynamic polarization curves and electrochemical impedance spectroscopy （EIS）. The structure of PAM film on mild steel was investigated by using physicochemical methods such as elemental analysis of C, H, N, physical chemical methods and FTIR spectrometer. The influence of scan repetition and scan rate on the formation of polymer film was studied at a current density of 1 mA/cm2. The results of these studies reveal that the corrosion resistance of the PAM-coated mild steel was significantly higher and the corrosion rate was considerably lower than that of uncoated steel. The PAM film was formed with lower sweep rate leading to more positive shift of corrosion potential and greater charge transfer resistance, reflecting higher inhibition for corrosion of the mild steel.
基金National Natural Science Fundation of China (50499334)
文摘For a long time, chromate incorporated conversion coatings have been drawn special attention in corrosion protection of aircraft-used aluminum alloys. However, ever-increasing environmental pressures requires that non-chromate conversion coatings be developed because of the detrimental carcinogenic effects of the chromate compounds. In recent years, the sol-gel coatings doped with inhibitors were developed to replace chromate conversion coatings, and showed real promise; A sol-gel coating was prepared and its anti-corrosion behavior was investigated using the potentiodynamic scanning （PDS） and the electrochemical impedance spectroscopy （EIS）. It is found that the sol-gel coating obtained by the hydrolysis and condensation of 3-glycidoxypropyltrimethoxysilane （GPTMS） and tetramethoxysilane （TMOS） is prone to form defects if cured at the room temperature, whereas if cured at a higher temperature （100℃）, these flaws can be avoided. Furthermore, it can be seen that addition of anti-foam agents and surfactants will reduce the faults if cured at the room temperature. Effects of the corrosion inhibitors, CeCl3 and mercaptobenzothiazole （MBT）, in the sol-gel coatings on 2024-T3 aluminum alloy were also investigated. Results show that the corrosion resistance of the sol-gel coatings containing CeCl3 proves to be better than that of the pure and MBT added sol-gel coatings by the electrochemical methods.
