Moving Forward Every Day — 3/29/2010
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Moving Forward Every Day – We hope that all members who wish to participate can learn and make progress every day: If the concentration of trivalent chromium in the chromium plating solution is too high, how can it be removed? We welcome active discussions on this topic, so that those who already know the answers can reinforce their knowledge, while those who don’t can improve their understanding, thereby achieving the goal of learning together and improving together. To facilitate scoring, it is recommended to hide visible replies. The event lasts for one week; posts submitted after that period do not need to be hidden, and moderators will no longer rate them
To reduce the content of trivalent chromium in the chromium plating solution, electrolysis must be carried out using a high current intensity on both the small cathode surface and the large anode surface. Trivalent chromium is oxidized to hexavalent chromium at the anode. The specific method involves heating the solution to 80°C, using a thin iron rod as the cathode, with the anode area being ten to several times that of the cathode; the anode current density should be 1.8–2 A/dm². The electrolysis time depends on the amount of trivalent chromium present; the higher the temperature, the better the effect of removing trivalent chromium.
To reduce the content of trivalent chromium in the chromium plating solution, electrolysis must be carried out with a high current intensity on a small cathode surface and a large anode surface. Trivalent chromium is oxidized to hexavalent chromium at the anode. The specific method involves heating the solution to 80°C, using a thin iron rod as the cathode, with the anode area being ten to several times that of the cathode; the anode current density is 1.8–2 A/dm². The electrolysis time depends on the amount of trivalent chromium present; the higher the temperature, the better the effect of removing trivalent chromium. 1# Green Hand
To reduce the content of trivalent chromium in the chromium plating solution, electrolysis must be carried out with a high current intensity on the small cathode surface and the large anode surface.
To reduce the content of trivalent chromium in the chromium plating solution, electrolysis must be carried out with a high current intensity on a small cathode surface and a large anode surface. Trivalent chromium is oxidized to hexavalent chromium at the anode. The specific method involves heating the solution to 80°C, using a thin iron rod as the cathode, with the anode area being ten to several times that of the cathode; the anode current density is 1.8–2 A/dm². The electrolysis time depends on the amount of trivalent chromium present; the higher the temperature, the better the effect of removing trivalent chromium.
To reduce the content of trivalent chromium in the chromium plating solution, electrolysis must be carried out with a high current intensity on a small cathode surface and a large anode surface. Trivalent chromium is oxidized to hexavalent chromium at the anode. The specific method involves heating the solution to 80°C, using a thin iron rod as the cathode, with the anode area being ten to several times that of the cathode; the anode current density is 1.8–2 A/dm². The electrolysis time depends on the amount of trivalent chromium present; the higher the temperature, the better the effect of removing trivalent chromium
Answer: To reduce the content of trivalent chromium in the chromium plating solution, electrolysis must be carried out with a high current intensity on a small cathode surface and a large anode surface. Trivalent chromium is oxidized to hexavalent chromium at the anode. The specific method involves heating the solution to 80°C, using a thin iron rod as the cathode, with the anode area being ten to several times that of the cathode; the anode current density is 1.8–2 A/dm². The electrolysis time depends on the amount of trivalent chromium present; the higher the temperature, the better the effect of removing trivalent chromium.
During the chromium plating process, it is inevitable that trivalent chromium is generated in the plating electrolyte due to the reduction of chromic anhydride at the cathode. At the start of electrolysis with the newly prepared chromium plating solution, the concentration of trivalent chromium gradually increases from zero, eventually reaching equilibrium due to the oxidation of trivalent chromium at the anode. Trivalent chromium is the main component in forming the colloidal film, but its content must also be appropriate in order to obtain a chromium layer of good quality. When the content of trivalent chromium is too high, the resulting colloidal film becomes very dense, which reduces the area covered by a shiny coating; the resulting coating is grayish and rough, similar to the coating obtained when the sulfuric acid content is low or the temperature is low. When the content of trivalent chromium is too low, the colloidal film is discontinuous, leading to an uneven coating – in some areas, no coating is even present – a situation similar to that that occurs when the sulfuric acid content is too high. In a properly functioning chromium plating electrolyte, the concentration of trivalent chromium ranges from 1 to 3 grams per liter (expressed as Cr2O3). The concentration of trivalent chromium is determined by the ratio of the anode current density to the cathode current density; it is advisable to keep this ratio at 0.5, meaning that the anode area should be twice that of the cathode area.
This post was last edited by j16119 on 2010-3-28 at 22:55. Electrolysis is carried out with a high current intensity on the small cathode surface and the large anode surface; trivalent chromium is oxidized to hexavalent chromium at the anode. The solution is heated to 80°C, a thin iron rod is used as the cathode, the anode area is ten to several times that of the cathode, and the anode current density is 1.8–2 A/dm². The electrolysis time depends on the amount of trivalent chromium present; the higher the temperature, the better the effect of removing trivalent chromium
To reduce the content of trivalent chromium in the chromium plating solution, electrolysis must be carried out with a high current intensity on a small cathode surface and a large anode surface. Trivalent chromium is oxidized to hexavalent chromium at the anode. The specific method involves heating the solution to 80°C, using a thin iron rod as the cathode, with the anode area being ten to several times that of the cathode; the anode current density is 1.8–2 A/dm². The electrolysis time depends on the amount of trivalent chromium present; the higher the temperature, the better the effect of removing trivalent chromium
If the concentration of trivalent chromium in the chromium plating solution is too high, how can it be removed? Answer: To reduce the amount of trivalent chromium in the plating solution, electrolysis must be carried out using a high current intensity on both the small cathode surface and the large anode surface. Trivalent chromium is oxidized to hexavalent chromium at the anode. The specific method involves heating the solution to 80°C, using a thin iron rod as the cathode, with the anode area being ten to several times that of the cathode; the anode current density should be 1.8–2 A/dm². The electrolysis time depends on the amount of trivalent chromium present; the higher the temperature, the better the effect of removing trivalent chromium.