korrutus

Korrutus is a process in materials engineering that involves applying a layer of material onto the surface of a substrate to alter its properties. The resulting layer, or coating, can serve protective, functional, or decorative purposes. The term is used in Finnish and Estonian language contexts and is commonly translated as coating or plating in English.

Common coating methods include electroplating, where an electric current drives metal ions to deposit on a conductive surface; hot-dip galvanizing, in which parts are submerged in molten metal; and electroless plating, which deposits metal without external power. Thin-film coatings are produced by physical vapor deposition or chemical vapor deposition; powder and spray coatings apply organic or inorganic materials.

Coatings may be metallic, ceramic, polymeric, or composite. Substrates range from steel and aluminum to plastics and ceramics. Applications span corrosion protection and wear resistance in automotive and industrial equipment, electrical and electronic components, tool surfaces, architectural finishes, and consumer goods. Decorative coatings, such as chrome or nickel finishes, are also common.

Key considerations include adhesion between coating and substrate, coating thickness, uniformity, and defect control. Environmental and safety constraints address waste management, emissions, and the use of hazardous chemicals. Quality assessment often involves nondestructive testing, adhesion tests, and thickness measurements.

Historically, coating practices date to ancient metalworking, but modern plating and surface finishing expanded rapidly during the 19th and 20th centuries with the development of electrochemistry and industrial processes. Ongoing advances seek higher performance, lower environmental impact, and new coating chemistries for emerging applications.