Post-treatment of chrome plating: electrochemical removal method of chrome plating

The parts are used as anodes and put into 10%-20% sodium hydroxide or potassium hydroxide solution, and the cathodes are nickel plates or nickel-plated steel plates. The working specifications are as follows:

The voltage is 5～12V, the current density is 5～15A/dm2, or higher, the temperature is room temperature; but when acceleration is needed, it must be heated to 70～80℃. The acting time depends on the thickness of the coating, ranging from a few minutes to a few hours.

The following phenomena indicate that the withdrawal effect has been completed:

①The pointer on the voltmeter swings suddenly and the voltage suddenly increases;

②Oxygen no longer escapes from the anode (parts); chromium is used as the anode during electrolysis and dissolves into chromate, which is easily soluble in water and the solution turns yellow.

Steel and cast iron parts still maintain their original polished surface after dechroming by these methods; brass and copper parts become darker in color and need to be polished again.

Regardless of the method used, after removing the chromium, the parts should be rinsed carefully with running cold water, then immersed in hot water, dried, and heated at a temperature of 150～180℃ for 1～2h. Get rid of the gas, then chrome plating. Chrome plating with color light must be polished first, and chrome without color light must be cleaned with emery cloth.