electrodeposition

Electrodeposition is a process in which a material, typically a metal, is deposited as a solid coating onto a conductive substrate by passing an electric current through an electrolyte solution containing ions of the coating material. The substrate serves as the cathode, while a second electrode acts as the anode. When current is applied, metal ions in the bath are reduced at the cathode and form a coherent metal layer on the surface; at the anode, metal may dissolve to replenish ions or an inert material may be used.

The bath composition, temperature, pH, agitation, current density, and additives determine deposition rate, film thickness, grain structure, and coating quality. Common coatings include copper, nickel, zinc, tin, chromium, gold, and silver, applied for corrosion protection, wear resistance, electrical conductivity, and decorative finishes. Additives such as brighteners, leveling agents, and suppressors influence brightness, uniformity, and the ability to coat complex geometry—a property known as throwing power. Substrates typically undergo cleaning and surface preparation to ensure adhesion and to remove oxides and contaminants.

Electrodeposition can be performed in aqueous or non-aqueous electrolytes and may involve single-metal deposits or alloy and composite coatings (for example, nickel–phosphorus or nickel–silicon carbide). Process control aims for uniform thickness, adhesion, and intended microstructure, while waste treatment and emissions considerations address environmental and safety concerns. Compared with other coating methods, electrodeposition offers cost efficiency, scalable production, and strong adhesion, making it a dominant technique in metal finishing, electronics, automotive, and decorative industries.