When we use decorative chromium plating additives, the workpiece can obtain a bright chromium plating layer with good coverage.Sometimes the brightness of the chrome plating layer on the workpiece is very poor. What is the reason?
Bigolly Technology has made analysis based on field experience and characteristics of decorative chromium plating additives Cr-9 for product,it mainly includes the following four points:
1. The ratio of chromic anhydride to sulfuric acid in the plating solution is not within the process range.In general decorative chromium plating process, the ratio of chromic anhydride to sulfuric acid is 200:1.With the increase of the concentration of chromic anhydride, the conductivity of the coating increases, and the covering capacity of the coating also increases, but the current efficiency of the cathode decreases.When the sulfuric acid is insufficient, the chromium coating is relatively rough; When the sulfuric acid content is high, there is no chromium in the low current density area of the coating.Therefore, their content and proportion should be strictly controlled in the production process.
2. The current density does not match.The current density of chromium plating has a great relationship with the performance of the bath and the appearance of the coating.When the current density is low, the current efficiency of chromium plating is low, and the brightness of the coating is also poor.Bigolly suggested that the current density during chrome plating should be controlled above 15A/dm2.
3. The concentration of trivalent chromium in the plating solution is too high.When the concentration of trivalent chromium in the plating solution is high, the colloid film formed on the chromium layer is thick and dense, the sulfuric acid is difficult to dissolve, and the chromium layer can only grow on the original grains, resulting in rough, dark and lusterless coating crystals.
4. Iron, copper, zinc and other impurities in the plating solution are too high.The iron ions in the plating solution mainly come from the accumulation of workpiece dropping and workpiece dissolution.When the iron impurity content in the bath is greater than 8g/L, the conductivity of the bath decreases, the current is unstable, and the bright range of the coating decreases.However, when the copper impurity in the plating solution is greater than 5g/L and the zinc impurity is greater than 3g/L, the coating coverage and bright range will be significantly reduced.
Therefore, when using decorative chromium plating additives, we should pay attention to the above four points to ensure that the workpiece coating has good brightness.If you are interested in decorative chromium plating additives, please contact the Bigolly customer service for free samples and detailed technical information!
If you want to know more about chrome plating, you can check "Industry News".
