Hráefnisönd

Hráefnisönd, literally “breath of material,” is a term used in Icelandic technical discourse to describe the release of volatile compounds from a material under certain conditions. It corresponds to the English concept of outgassing or off-gassing and is of particular concern in vacuum systems, semiconductor manufacturing, aerospace engineering, and materials science. Outgassing can degrade vacuum performance, contaminate surfaces, alter optical properties, or affect chemical reactions in enclosed environments.

Causes and mechanisms: Outgassing arises from desorption of adsorbed species on a surface, diffusion of trapped gases from within the bulk, and evaporation of volatile constituents at elevated temperatures. The amount and composition depend on the material type (polymers, adhesives, coatings, ceramics, metals), surface area, storage history, exposure to moisture, and processing conditions.

Measurement and implications: To quantify outgassing, methods such as mass spectrometry, thermal desorption spectroscopy, or GC-MS are used in controlled tests. Results are often reported as the outgassed mass or rate (for example ng/cm²·h) and as partial pressures in vacuum environments. High outgassing can lead to contamination of sensors, optics, or surfaces, and can limit the achievable vacuum level.

Mitigation and control: Approaches include selecting low-outgassing materials, thorough bake-out and preconditioning before assembly, surface treatments or coatings, and careful storage. Design choices that minimize exposed surface area and the use of cleanroom-compatible processes also help reduce outgassing effects.