elektroplatointi

Elektroplatointi, or electroplating, is a method to deposit a metal coating on a conductive workpiece by controlled electrolysis in an electrolyte containing dissolved metal ions. The coating can improve corrosion resistance, hardness, wear protection, appearance, or electrical properties, and is widely used on automotive parts, hardware, electronics, and jewelry.

In practice, the workpiece serves as the cathode, while the plating metal or a soluble anode supplies metal ions. When direct current passes through the bath, metal ions are reduced and deposit onto the cathode, forming a thin, adherent layer. The thickness is governed by current density, plating time, bath composition, temperature, and agitation. Pretreatment steps such as cleaning, degreasing, etching, and activation are essential to ensure adhesion and surface quality. Masking may be used to protect areas not intended for plating.

Common coating metals include copper for a conductive seed layer; nickel for hardness and corrosion resistance; chromium for bright finishes and hardness; zinc for sacrificial protection; and tin, gold, or silver for electronics and decorative finishes. Plating baths may be based on cyanide-containing solutions, which require careful handling and environmental controls; alternative cyanide-free formulations are increasingly used.

Variants of electroplating include barrel plating and rack plating, which differ in how parts are immersed in the bath. Environmental, health, and safety considerations influence process design, waste treatment, and regulatory compliance. Electroplating remains a versatile method for enhancing performance and aesthetics across many industries.