植酸封闭对钢芯铝绞线表面Ni-P镀层耐蚀性的影响

Effects of Phytic Acid Sealing on Corrosion Resistance of Electroless Ni-P Plating Layer on Aluminum Cable Steel Reinforced

在钢芯铝绞线中的铝股线表面化学镀镍磷可以改善其在沿海工业大气中的耐蚀性,但工艺流程较复杂。在铝股线表面不经过二次浸锌工艺直接化学镀Ni-P后再进行植酸封闭改性,通过红外光谱(FTIR)、扫描电镜(SEM)和能谱(EDS)对镀层进行形貌和成分分析,通过在1 mol/L H_2SO_4+3%Na Cl混合溶液中的浸蚀试验和Tafel极化曲线比较镀层的耐蚀性。结果表明:经植酸封闭后,铝股线表面的Ni-P镀层更均匀,外层由于植酸与镀层相互作用,局部出现细小孔洞,但腐蚀介质不易渗入基体;腐蚀电位正移,腐蚀电流变小,腐蚀前后形貌变化不大,结合力仍很好,植酸封闭后镀层的耐蚀性更好。

In order to improve the corrosion resistance of aluminum cable steel reinforced(ACSR),electroless Ni-P plating was conducted on the aluminum stranded wires without the second dip galvanizing technique and then followed by phytic acid sealing.The morphology and composition of the plating layer were analyzed by FTIR,SEM and EDS.In addition,the corrosion resistance of the plating layer was compared by etching experiments and Tafel polarization curves in 1 mol/L H_2SO_4 + 3%NaCl mixed solution.Results showed that Ni-P chemical plating layer sealed by phytic acid was more uniform.On the partial layer surface,fine small boles due to the interaction between phytic acid and plating layer emerged,which made less corrosive medium into the substrate.Therefore,the corrosion potential moved positively and the corrosion current was decreased.Furthermore,little change in morphology happened and interface bonding strength remained good before and after corrosion.After the phytic acid sealing,the corrosion resistance of the plating layers became better.