高耐蚀性锌铁低磷三元合金电镀工艺的开发与研究 第一部分──电镀工艺及镀层、镀液性能

Development and research of high-resistance low-phosphorus zinc–iron–phosphorus ternary alloy electroplating process——Part I. Electroplating process and properties of bath and deposit

开发了一种锌铁低磷三元合金电镀工艺，镀液组成及工艺条件为：ZnCl270～100g／L，KCl 160～200g／L，CH，COO Na5—40g／L，CH3COOH2～10mL／L，FeCl25～10g／L，稳定卉45～30g/L，含磷细化剂0．5～20．0g／L，光亮剂15～25mL／L，室温，pH2．5～4．0，电流密度0．5～2．0A／dm^2。测试了镀液的深镀能力、光亮电流密度范围、缓蚀效果及耐老化性能。以热震法和弯曲法测试了镀层的结合力，采用扫描电镜和透射电镜分析了镀层的微观形貌。通过在5％（质量分数）NaCl溶液中的极化曲线测量以及中性盐雾试验，考察了镀层的耐蚀性。该新型锌铁磷三元合金工艺成本低、稳定，镀层耐热冲击和耐腐蚀的性能优良。

A process for electroplating low-phosphorus Zn-Fe-P temary alloy was developed. The bath composition and operation conditions are as follows： ZnCl2 70-100 g/L, KCl 160-200 g/L, CHaCOONa 5-40 g/L, CH3COOH 2-10 mL/L, FeCl2 5-10 g/L, stabilizing agent 5-30 g/L, phosphorus-containing refining agent 0.5-20.0 g/L, brightening agent 15-25 mL/L, room temperature, pH 2.5-4.0, and current density 0.5-2.0 A/dm^2. The throwing power, current density range for obtaining bright coatings, corrosion inhibition performance, and aging resistance of the plating bath were tested. The adhesion strength of the Zn-Fe-P coating was determined by thermal shock and bending tests. The microscopic morphology was analyzed by scanning electron microscopy （SEM） and transmission electron microscopy （TEM）. The corrosion resistance was examined by polarization curve measurement in 5wt% NaC1 solution and neutral salt spray （NSS） test. The novel Zn-Fe-P ternary alloy plating process features low cost and high stability, and the coatings obtained have good resistance to thermal shock and corrosion.