Pokovení

Pokovení, or plating, is the deposition of a thin metallic layer onto a substrate to modify surface properties. It encompasses electroplating (galvanické pokovení), electroless plating, and vacuum-deposition methods such as physical vapor deposition (PVD) and chemical vapor deposition (CVD). The goal is to improve corrosion resistance, wear resistance, electrical conductivity, reflectivity, or appearance.

Common plating methods and metals. Electroplating uses an electrolytic cell in which the substrate is the cathode and metal ions in solution are reduced onto its surface. Metals such as nickel, chromium, copper, zinc, gold, and silver are widely used, often as decorative or functional coatings or as alloys like nickel–phosphorus. Electroless plating achieves coating without external current by chemical reduction, providing uniform coverage on complex shapes; typical systems include nickel–phosphorus and nickel–boron. PVD and CVD coatings are applied in vacuum or controlled atmospheres and yield hard, wear-resistant surfaces such as titanium nitride (TiN) or diamond-like carbon, as well as decorative metallic finishes.

Process and quality aspects. Key steps include substrate cleaning, degreasing, activation, deposition under controlled temperature and time, and post-treatment such as rinsing and drying. Thickness typically ranges from sub-micrometer decorative layers to several tens of micrometers for wear protection; measurement and adhesion testing ensure quality. Surface finish can be bright, matte, or colored depending on the plating chemistry.

Environmental and safety considerations. Plating baths may contain hazardous substances, including cyanides and heavy metals, requiring proper handling, containment, and waste treatment. Regulatory regimes increasingly favor safer alternatives and emissions controls.

Applications. Pokovení is widely used in automotive, electronics, tooling, and jewelry industries to extend service life, improve performance, or achieve specific aesthetic qualities.