chromeplating

Chromeplating is an electroplating process that deposits a thin layer of chromium onto a base metal or substrate. The resulting finish provides enhanced hardness, wear resistance, and corrosion resistance, as well as a distinct bright appearance in decorative uses. Two broad types are recognized: decorative chrome plating, which yields a highly reflective, aesthetically pleasing surface; and hard chrome plating, which produces a thicker, harder coating designed for wear protection and functional components.

Substrate preparation is critical: parts are thoroughly cleaned, degreased, and activated; nonferrous substrates often receive a nickel strike to promote adhesion. The chromium layer is deposited from an electrolytic bath containing chromium in hexavalent form (Cr(VI)). The anodes are chromium metal and the cathode is the workpiece; current is passed to drive chromium deposition. Baths are carefully controlled for temperature, agitation, pH, and evolving hydrogen; brightening agents create the glossy finish. Decorative chrome typically uses thin deposits; hard chrome is thicker and harder, with different bath chemistries and plating conditions. After deposition, parts are rinsed and may undergo sealing, passivation, or post-polishing.

Because hexavalent chromium compounds are toxic and carcinogenic, chrome plating operations are subject to strict occupational exposure limits and environmental controls. Methods to reduce Cr(VI) use include process automation, ventilation, and switching to trivalent chromium baths, though the latter can be less forgiving and require different pretreatment and process controls.

Common applications include automotive trim and bumpers, bicycle parts, faucets and hardware, cutting tools and bearings, and aerospace components.