Post-plating Treatment

Electroplating is the final process of electroplating engineering. No matter how good the plating is, how high the quality of the coating is, if the post-treatment is improper, it will be all kinds of color stains on the surface of the coating or make the coating surface discoloration, and even the existence of stress, causing the coating rupture or fall off and other accidents, so it is necessary to carry out post-treatment, to ensure that the surface of the coating is smooth and intact, to ensure the quality of the plating products.

Generally speaking, after plating, appropriate treatment should be done to meet the requirements of use. After plating, at least several times of washing should be done in order to remove the acid, alkali, salt and other chemicals left on the surface of the coating. Then to shake dry, dry, prevent rust or discoloration immediately, different metal plating parts have different post-treatment methods. Such as galvanized layer to passivation treatment, therefore, plating after treatment and plating before treatment is equally important. It is an important measure to ensure product quality.

After electroplating, the coating is treated to enhance various properties of the coating, such as corrosion resistance, resistance to discoloration, etc., including dehydration, passivation, sealing, dehydrogenation and other processes.

Dehydration: including scalding dry, shake dry, drying, adding dehydrating agent

Passivation: Improve the corrosion resistance and discoloration resistance of the coating. Common passivation colors are silver white, blue white, five color, black.

Closed: enhanced coating anti-discoloration

Dehydrogenation: enhance the toughness of the substrate metal and coating

Dehydrogenation

When parts are pickling, cathode plate deoiling and electroplating, hydrogen may ooze in the lattice of coating and substrate metal, resulting in lattice distortion, increased internal stress and brittleness.

Prevent hydrogen penetration in the production process: pickling process time selection, mechanical rust removal, cathode movement, after plating hydrogen removal, before the parts dehydrogenation are not passivated, in addition to hydrogen parts to re galvanized, and then passivated.

High strength steel (HRC28 and above), spring parts and other parts of electrogalvanizing, chromium plating after hydrogen removal treatment.

Process of hydrogen removal:

190-230 ℃

More than 3 hours

Carburizing and tin welding parts temperature 140℃-160℃

Hydrogen removal should be carried out immediately after plating, and the parts should be scrapped after more than 4 hours.

Other steel parts must be dehydrogenated within 4 hours after electroplating.

Spring parts, thin-wall parts (wall thickness less than 0.5mm), high-strength steel parts, must be dehydrogenated.

Copper and copper alloy parts can be free of hydrogen removal.

For parts that cannot be heated too high, a lower temperature (140℃-160℃) can be used to extend the time of hydrogen removal.