In the production process of alkaline galvanizing, sometimes the coating brightness of the workpiece is not enough, and the operator will add more alkaline galvanizing brightener to improve the brightness of the galvanizing layer.And sometimes the coating is not bright, even if the alkaline galvanized brightener is added, the brightness of the coating is not improved, why is this?
The brightness of the galvanized layer of the workpiece is not enough. Sometimes it is not that the concentration of the alkaline galvanized brightener is insufficient.There may also be the following reasons:
1. Improper operation of the plating solution.If the temperature of the plating solution is too high or the cathode current density is too small, the adsorption of the brightener is relatively weak, and the brightness of the coating will be darker.Therefore, we need to select the appropriate current density at the appropriate temperature to refine the crystallization of the coating and improve the brightness.
2. The proportion of zinc alkali in the bath is wrong.When the zinc content in the bath is too high and the alkali content is too low, the brightness of the galvanized layer will be uneven, and sometimes the phenomenon of yin and yang surfaces will appear.Therefore, we should strictly control the concentration of zinc and alkali in the alkali-zinc bath to keep the bath with good electrochemical properties and obtain an excellent zinc coating.
3. There are too many metal impurities in the plating solution.There is no other strong complexing agent in the alkaline zinc plating solution, and the plating solution is more sensitive to impurities.It is easy to accumulate metal impurities such as copper, lead, iron, and cadmium in the production process.When lead>15mg/L, copper>50mg/L and iron>50mg/L in the bath, the zinc coating will appear dark, black or black stripes.Therefore, in the production process, we should regularly use sodium sulfide or zinc powder to treat metal impurities in the electroplating solution.
Therefore, in the process of galvanizing production, the brightness of the galvanized layer of the workpiece is not enough, not necessarily because the concentration of alkaline galvanizing brightener is insufficient.The operating conditions of the bath and the influence of metal impurities should be considered.If you are interested in alkaline galvanizing brightener,