Zn-Fe合金镀层耐蚀性研究

Study on corrosion Resistauce of Zn-Fe Alloy Deposit

通过改变工艺条件,可以从碱性溶液中获得含 Fe0.4～0.8%的 Zn-Fe合金镀层。试验表明这种镀层的耐蚀性是普通镀锌层的2倍。含 Fe 量不同的镀层其耐蚀性也不同。含 Fe 在0.4～0.8%的镀层在5%NaCl 溶液中在稳定电位条件下处于钝化区,而且镀层的极化电阻比较大,是镀锌层的2倍以上,而镀锌层在同样溶液中处于活化溶解区,有很大的溶解电流,而且极化电阻较小。腐蚀后形貌观察也表明 Zn-Fe 合金镀层与镀锌层的特征不同,呈花球状形貌。正是由于上述差异决定了 Zn-Fe 合金镀层的耐蚀性是优良的。

Zn-Fe alloy deposit containing 0.4 to 0.8wt% Fe has been achieved in alkaline zincate solution by changing electroplating conditions.Neutral salt spray test shows that the corrosion resistance of Zn-Fe alloy desposit is superior to that of zinc coat- ing.Corrosion resistance of Zn-Fe alloy is found to be dependant on Fe content in the alloy.Coating with 0.4 to 0.8wt% Fe has a passivation range under stable pote- ntial conditions when it immerses in 5% NaC1 solution and polarization resistance of deposit is great.In the same solution,Zn coating remains in an anodic activation di- ssolve range.The corrosion dissovle current is great and the polarization resistance weak.The morphology observation after corrosion shows tha tthe characteristics of Zn- Fe alloy deposit is different from that of Zn deposit,which is in bloom-ball morph- ology.