The main factors affecting the adhesion of chrome plating

The pre-plating treatment includes the main processes of oil removal, sand blowing and activation. 1) Oil removal. The oil stains on the surface of the plated parts cause the chromium layer to be unable to deposit or the plating layer in the oil stains during electroplating, and the oil removal treatment is required 2) sand blowing. If the passivation film on the surface of the plated part is not completely removed, it will cause the chromium layer to deposit difficult or relatively loose and easy to fall off. Sandblasting can effectively remove the passivation layer on the metal surface, and can make the surface rough, strengthen the mechanical bite force, thereby helping to improve the mechanical bonding between the coating and the substrate. But sandblasting will increase the stress of the workpiece, and it is not suitable for some parts that require high surface roughness or matching accuracy.

3) Activation. The activation process is the key to titanium alloy electroplating. It makes the oxide film on the surface of the titanium alloy removed, and at the same time generates a thin conversion film or metal bottom layer, so that the titanium substrate is not re-oxidized before electroplating, and at the same time, it can make the metal bottom layer get good The deposited coating. This work is to place the plated parts in a mixture of concentrated HC1 and H2SO4 for hydrogenation treatment to combine the titanium surface with hydrogen to form a gray to black continuous film. This film can protect the substrate from oxidation before electroplating. It can ensure good coating adhesion.