postplating

Postplating refers to a set of finishing operations applied after an initial plating deposit has been laid down, with the aim of improving performance, appearance, or compatibility with subsequent processes. It encompasses chemical, electrochemical, and mechanical treatments that condition the plated surface without removing the underlying layer. Postplating is used across metal finishing, electronics, automotive, aerospace, and jewelry manufacturing.

Common postplating operations include cleaning and rinsing to remove residual chemicals and particulates, drying to prevent water spots, and surface brightening or polishing to achieve desired luster and smoothness. Sealing or passivation, such as chromate conversion coatings on zinc or zinc alloys, is used to enhance corrosion resistance. Heat treatments or bake cycles are applied to relieve internal stresses, stabilize the deposit, and drive out absorbed hydrogen that can cause embrittlement or popcorning in subsequent steps. Depending on the application, additional steps may include chemical stabilization, leveling or burnishing, and application of protective topcoats or polymer seals to improve wear resistance or environmental protection.

Industry considerations for postplating include compatibility with the base plating chemistry, service environments, and downstream processes (for example, solderability in electronics or paint adhesion in automotive parts). Process control typically covers deposit thickness, uniformity, adhesion, surface roughness, and corrosion resistance, with testing such as adhesion tests or salt spray exposure informing quality assurance.

See also: electroplating, passivation, chrome plating, chromate conversion coating.