摘要
Electroless Ni-P/nano-CeO2 composite coating was prepared in acidic condition, and its microstructure and corrosive property were compared with its CeO2-free counterpart.Scanning electronic microscopy(SEM), transmission electronic microscopy(TEM), X-ray diffraction spectrometer(XRD), and differential scanning calorimeter(DSC) were used to examine surface morphology and microstructure of the coating.Corrosive investigation was carried out in 3%NaCl+5%H2SO4 solution.The results showed that Ni-P coating had partial amorphous structure mixed with nanocrystals, whereas the Ni-P/CeO2 coating had perfect amorphous structure.In high temperature condition, Ni3P precipitation and Ni crystallization occurred in both coatings but at different temperatures, whereas the Ni-P/CeO2 coating had sintered phase of NiCe2O4 spinels.The anticorrosion property and passivity were improved in the CeO2-containing coating due to its less liability to undergo local-cell corrosion than its CeO2-free counterpart.During the co-deposition process, some Cen+(n=3, 4) ions may be adsorbed to the metal/solution interface, hinder nickel's crystal-typed deposition and promote phosphorous deposition.The nano-CeO2 doping finally resulted in the coating' perfect amorphous structure and good anti-corrosive property.
Electroless Ni-P/nano-CeO2 composite coating was prepared in acidic condition, and its microstructure and corrosive property were compared with its CeO2-free counterpart.Scanning electronic microscopy(SEM), transmission electronic microscopy(TEM), X-ray diffraction spectrometer(XRD), and differential scanning calorimeter(DSC) were used to examine surface morphology and microstructure of the coating.Corrosive investigation was carried out in 3%NaCl+5%H2SO4 solution.The results showed that Ni-P coating had partial amorphous structure mixed with nanocrystals, whereas the Ni-P/CeO2 coating had perfect amorphous structure.In high temperature condition, Ni3P precipitation and Ni crystallization occurred in both coatings but at different temperatures, whereas the Ni-P/CeO2 coating had sintered phase of NiCe2O4 spinels.The anticorrosion property and passivity were improved in the CeO2-containing coating due to its less liability to undergo local-cell corrosion than its CeO2-free counterpart.During the co-deposition process, some Cen+(n=3, 4) ions may be adsorbed to the metal/solution interface, hinder nickel's crystal-typed deposition and promote phosphorous deposition.The nano-CeO2 doping finally resulted in the coating' perfect amorphous structure and good anti-corrosive property.
基金
supported by the National Natural Science Foundation of China (29233011)
the Natural Science Foundation of Jiangsu Province (07KJD430246)