铝元素对锌镀层耐蚀性的影响

研究了用复合电沉积法制备的锌铝镀层在微酸性腐蚀介质中的耐蚀性。试验结果证明,氢氧化铝也能改善镀层的耐蚀性,但不如铝粉的作用显著。EPMA和ICP显示含氢氧化铝和含铝粉镀层中的铝呈均匀分布状态,但前者铝的含量为50ppm,后者为0.15wt％。x-射线衍射法揭示溶液中的氢氧化铝能使镀层的结晶细致,晶面择优取向程度增加。当镀液中含有铝粉时,所得镀层的结晶晶面的择优程度更大,结构则成为层状的。因此,氢氧化铝和铝粉是通过提高镀层的晶面择优取向程度,从而改善了其耐蚀性能。

The Effect of Aluminium Element on Corrosion Resistance of Zinc Composite Coating

The effect of aluminium element on corrosion resistance of zinc composite coating was investigated. The experimental results show that A1(OH)3 can also improve corrosion resistance of the coating but not so as marked as aluminium particles. EPM A and ICP tests show that Al element are uniformly dispersed in zinc coatings containing A1(OH)3 or Al particles, though aluminium content in the former is 50 ppm and in the latter, 0.15wt%. x-ray diffraction reveals that the preferred orientation degree of (101) plane of zinc crystal in the coating obtained from bath containing A1(OH )3 colloid is increased. For the coating obtaine from bath containing Al particles, its (101) crystal plane preferred orientation degree is much higher an its structure is laminate. Therefore, A1(OH )3 colloid and Al particles are able to increase degree of preferred orientation of the (101) plane of zinc crystal in the zinc composite coatings, so that improving the corrosion resistance of the coating.