Pinnoite

Pinnoite is a Finnish term for a surface coating or plating applied to a substrate to modify its properties. In a broader sense, pinnoite covers any process that deposits a layer on a material’s surface to achieve protective, functional, or decorative effects. Coatings can be metallic, such as zinc, nickel, or chromium layers, or non-metallic, including paints, polymer films, or ceramic oxides.

Coatings are applied by a range of processes. Metallic coatings include electroplating and electroless plating, as well as hot-dip galvanizing. Non-metallic coatings include liquid paints, powder coatings, ceramic layers, and polymeric films. Advanced coatings are produced by physical vapor deposition (PVD) or chemical vapor deposition (CVD), and by thermal spraying.

Typical thicknesses span from a few micrometres to several hundred micrometres, depending on function and process. Before coating, surfaces are cleaned and pre-treated (degreasing, etching, pickling, priming) to ensure adhesion. The adhesion and performance of a pinnoite depend on surface roughness, cleanliness, and compatibility of materials.

Common applications include automotive components, fasteners, machinery, electronics, construction materials, and medical devices. Pinnoite aims to improve corrosion resistance, reduce wear and friction, alter electrical or optical properties, and provide aesthetic finishes.

Quality is controlled with tests for adhesion (for example, standardized adhesion tests), thickness measurement (X-ray fluorescence or profilometry), hardness, and corrosion performance (salt spray or cyclic tests). Environmental considerations include reducing hazardous substances; chromium(VI) plating is restricted in many regions, with chromium(III) plating and non-chromium coatings gaining prominence.

See also: galvanizing, electroplating, powder coating.