利用磷化渣配制复合磷化液

Preparation of Composite Phosphating Solution Using Phosphate Residue

采用固体废物磷化渣配制成复合磷化液，并用所配制的复合磷化液对A3钢试件进行磷化处理，形成磷化膜。通过正交实验确定了配制复合磷化液的较佳配方为：磷化液基础液加入量0．2L／L、氧化锌加入量5g／L、碳酸钠加入量6g／L、硝酸加入量12．5mL／L、浓磷酸加入量2．5mL／L、硫酸铜加入量0．3g／L。复合磷化液为浅绿色透明溶液，pH为4．0，总酸度为40，游离酸度为10，磷化温度为65℃，磷化时间为300～600s。所形成的磷化膜厚度为16．0μm，单位质量为26．875g／m^2，粗糙度为1．425μm，维氏硬度为124．27kgf／mm^2。磷化膜硫酸铜点滴时间为35s，耐盐水时间为8h，耐盐雾时间为4h，其物理性质和耐蚀性能均较佳。

A kind of composite phosphating solution was prepared using solid phosphate residue. Then it was used in the phosphating treatment of A3 steel sample to form phosphating coat. The optimum compositions for the composite phosphating solution were determined through the orthogonal experiments as follows： basic phosphating solution 0.2 L/L, zinc oxide 5 g/L, sodium carbonate 6 g/L, nitric acid 12.5 mL/L, concentrated phosphoric acid 2.5 mL/L and copper sulphate 0.3 g/L. The composite phosphating solution is a light green transparent solution with pH 4.0, TA 40 and FA 10. When phosphating temperature is 65 ℃ and phosphating time is 300 -600 s, the phosphating coat can form with 16.0 p,m of thickness, 26. 875 g/m^-2 of unit mass, 1. 425 μm of roughness and 124.27 kgf/mm^2 of HV hardness. The corrosion time of the phosphating coat is 35 s for CuSO4 drops, 8 h for salt water and 4 h for salt spray. It indicates that the physical properties and corrosion resistance of the phosphating coat are good.