| In this paper,Zr-Si normal temperature blocking agent was developed.The blocking agent does not contain free F-.The process is:ammonium fluorozirconate 7 g/L,sodium silicate 1 g/L,polyethylene glycol 0.2 g/L,sodium dodecyl sulfate 0.8 g/L,sulfosalicylic acid 0.6 g/L,blocking time 10 min,blocking temperature 25°C,pH 5.5.By SEM analysis,the pores on the surface of the Zr-Si closed sample disappeared.Through EDS and XPS analysis,Zr-Si closed sample contains Si,Zr,F elements,mainly ZrO2,SiO2,Al2SiO5 and other complex compounds deposited in the micropores to close;The corrosion resistance of the Zr-Si closed sample is improved by electrochemical test analysis.The medium temperature sealing agent with zinc acetate as the main salt has been developed.It does not contain nickel or fluorine.The specific process is:zinc acetate 9g/L,manganese acetate 4 g/L,calcium acetate 4 g/L,magnesium acetate 2 g/L,triethanolamine 20 g/L,sorbitol 0.3 g/L,thiourea 2 g/L,succinic acid 1.5 g/L,ammonium acetate 3 g/L;blocking time 40 min,blocking temperature 70°C,pH 6.0.By SEM analysis,the surface of the zinc acetate blocked sample show a petal crystal structure.Through EDS and XPS analysis,the surface of the zinc acetate blocked sample contains Zn,Mn,Ca,Mg elements,mainly ZnAl2O4,MgAl2O4,calcium oxides,manganese oxides and other complex compounds to close the micropores.Through electrochemical test analysis,the corrosion resistance of the zinc acetate blocked sample is improved.The effect of rare earth elements on Zr-Si and zinc acetate blocking is investigated.After the addition of the rare earth element,the self-corrosion potential of the closed sample becomes larger;the corrosion current density becomes smaller;the radius of the impedance arc becomes larger,which increases the corrosion resistance of the aluminum alloy.Through EDS and XPS analysis,the surface of the closed sample contains Ce and La elements,mainly to form CeO2,Ce2O3,La2O3 and La2（C2O4）3 deposited on the pores and surface of the oxide film. |
