Kyllästetys

Kyllästetys is a Finnish noun derived from the verb kyllästää, meaning to saturate. It refers to the act or state of becoming saturated, i.e., of filling a material or medium with as much of a substance as it can hold. In Finnish technical usage the term is most often linked to two contexts: chemical saturation and wood preservation.

In chemistry and materials science, kyllästys denotes the saturation of a solution or a medium with a solute. A solution is saturated at a given temperature when it contains the maximum amount of dissolved substance; adding more solute leads to precipitation or undissolved material. This concept is fundamental in processes such as crystallization, extraction, and environmental modeling, where solubility limits determine behavior and outcomes.

In wood science and construction, kyllästys most commonly refers to painekyllästys, a process in which wood is impregnated with preservatives under pressure. During the process, a preservative solution is forced into the wood to enhance durability and resistance to decay and insect attack. The resulting product, called kyllästetty puu (pressure-treated wood), is widely used for outdoor structures such as fences, decks, and posts. Preservative retention and penetration depth are controlled by standards and depend on wood species and intended use; modern formulations are typically copper-based and are selected for environmental and safety considerations.

Käytön kontekstista riippuen kyllästetystä voidaan puhua myös yleismielessä, jolloin se tarkoittaa jonkin aineen saavuttamaa täysi kyllästyneisyyttä.