| In this paper, the Al-Nd layer coating was electrodeposited on Q235 steel surface in Al Cl3-Na Cl-KCl molten salts with diferent content of Nd2O3. Effects of the diferent content of Nd on properties of Al-Nd alloy coating was studied. The microstructure, phase composition and corrosion resistance of the layers were investigated by SEM, XRD as well as electrochemical curve. The result showed that with adding Nd2O3 in molten salts, the aluminum grains deposited on the surface of coating became from spherical and needle-like structure to unform and dense and layered alloy structure; the contents of Nd in Al-Nd alloy coating had a significant impact on properties of the alloy coating and the alloy phase was composed of Al and Al3 Nd. Furthermore,when the content of Nd was 0.74% in Al-Nd alloy coating, the performances of corrosion resistance of coatings were best.The Al-Nd ceramic coatings was obtained in Al-Nd alloy coatings by micro-arc oxidation(MAO) in electrolyte solution. The influences of the content of Nd in the coating, the concentration of Na2 Si O3, Na OH and different additives on the microstructure, phase composition and corrosion resistance of ceramic coatings were investigated by SEM, XRD as well as electrochemical curve. The results indicated that the contents of Nd in Al-Nd alloy coating had a great influence on properties of ceramic coatings. What’s more, with the increase of Nd content in the coating, the microstructure of ceramic coatings was became from smooth to porous strcture; the aperture increased; the phenomenon of micro-arc oxidation and the MAO “volcanic pile” morphology became more and more obvious. In addition, when the content of Nd was 0.74% in Al-Nd alloy coating, the discharge holes were smaller and the corrosion resistance of ceramic coatings was the best. The performances of ceramic coatings could be significantly improved when Na OH, K2Cr2O7, H2O2, Na2WO4 and Na2B4O7·10H2O were added into Na2 Si O3 electrolyte. |
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