Outgassingtasoja

Outgassingtasoja is a conceptual framework used in materials science and vacuum engineering to categorize the outgassing behavior of materials in vacuum environments. The term combines outgassing with the Finnish plural suffix -tasoja, meaning levels or tiers.

Definition and purpose: Outgassingtasoja classifies materials by their propensity to release volatile compounds when exposed to vacuum, bakeouts, or elevated temperatures. The framework typically assigns a level such as low, moderate, or high based on standardized test results, helping engineers compare materials for vacuum-sensitive applications.

Measurement and criteria: Testing follows established standards (for example, ASTM E595 or NASA outgassing protocols) to quantify parameters like total mass loss (TML), collected volatile condensable materials (CVCM), and the outgassing rate. The outgassing rate is often reported in molecules per square centimeter per second. Materials with lower outgassing levels are preferred for spacecraft, optical components, and high-vacuum systems to minimize contamination and pressure rise.

Applications: The classification informs material selection, bakeout requirements, and long-term performance predictions for vacuum chambers, telescope optics, semiconductor fabrication equipment, and other environments where outgassing could affect performance or cleanliness. It also supports risk assessment, vendor qualification, and quality control in manufacturing.

Limitations: Levels depend on test conditions such as temperature, duration, and atmospheric exposure; real-world performance can vary due to aging, in-service contamination, or operation at different temperatures.

See also: Outgassing, vacuum technology, material testing, ASTM E595, NASA outgassing guidelines.