Additives
Chemicals such as wetting agents, leveling agents, brighteners, and grain refiners. Wetting agents are not electrochemically active. They are adsorbed on the surface of the substrate, and slow down the diffusion of the chemicals in the bath to the surface of the substrate. Brighteners, leveling agents, and most grain refiners, are electrochemically active. Current causes them to change and some of the additive gets incorporated into the deposit, while the rest stays in solution. The portion that stays in solution is called the breakdown product. Carbon treatment is required at some point, to remove the breakdown products, as stress will go out of control otherwise.

» More Electroplating Terms