氧化钙对钢铁黑磷化液的影响

Effect of Calcium Oxide on Black Phosphating Bath for Steel-iron

为了获得氧化钙含量适宜的锌钙系黑磷化液,采用X射线荧光光谱法(XRF)分析黑磷化液成分,研究了黑磷化膜的结构和膜层生长速度,利用电化学工作站测试磷化液的极化性能。结果表明:在磷化过程中随氧化钙含量增大,磷化液的Ca2+浓度变化显著。黑磷化膜的Ca元素含量随磷化时间延长而增长,氧化钙能调节黑磷化膜的生长速度,促使晶粒细化,膜层致密。当CaO达到0.50 mol/L时,膜层钙含量为6.32%,Zn含量为14.62%,晶体的粒径约为3～5μm,单位面积磷化膜的膜层重量约2.3 mg/cm2,黑磷化液的极化性能变弱。

The effect of calcium oxide（CaO） on phosphating was studied to obtain feasible black phosphating bath of Zn-Ca system.The components of the phosphating bath were analyzed by X-ray fluorescence（XRF）.The structure and growth rate of the phosphating film had been studied,and polarization curves of Q235 steel in the phosphating bath had been tested.Results showed that the concentration of Ca^2＋ in the phosphating bath changed dramatically with increasing of CaO,The diameter of the crystals decreased obviously and the film becames compact.The content of Ca and the growth rate of the film increased with prolong of phosphating time.When 0.50 mol/L CaO was added,the black phosphating coating with 6.32% Ca and 14.62% Zn was gained,the diameters of crystals were 3～5 μm,the weight of coating was 2.3 mg/cm^2,and the polarization capability of the phosphating bath becames lower.