passivoitu

Passivoitu is Finnish for "passivated" and refers to the state of having undergone passivation, a surface treatment that forms a protective, often chemically inert layer on a material to reduce reactivity and corrosion. The term is used in metallurgy, electronics, and biomedical contexts.

In metallurgy and materials science, passivation forms a thin, dense oxide or other compound on a metal surface, increasing resistance to corrosion. Common examples include chromium oxide on stainless steels and aluminum oxide on aluminum. The protective film is typically nanometers to micrometers thick and is designed to be adherent and, to some extent, self-healing if damaged. Passivation can be achieved by chemical treatments (for example, nitric acid or citric acid baths), electrochemical procedures, or thermal oxidation. The choice of method depends on the metal, the desired film, and the operating environment.

Applications include stainless steels, titanium and nickel-based alloys, and medical or dental implants, where passivation reduces metal ion release and improves biocompatibility. However, passivation is not permanent; films can be damaged by abrasion, chlorides, or high temperatures and may require re-treatment or supplementary coatings.

In electronics and photovoltaics, passivation describes the deposition of thin insulating or dielectric layers on semiconductor surfaces to reduce surface states, protect against moisture, and improve electrical performance. Common materials are silicon dioxide, silicon nitride, and aluminum oxide. The term passivated or passivoitu is used to describe components that have received such layers, enhancing device reliability.

In summary, passivoitu indicates a surface that has been treated to form a protective, inert layer that reduces undesired reactions, with methods and effects varying by material and application.