Desorption Process
Gas release from materials in high vacuum environments can degrade the pressure levels required for sensitive industrial processes. The outgassing rate of a polymer or metal determines how much gas is liberated per unit surface area per second. This parameter is critical for designing vacuum chambers used in semiconductor manufacturing and space exploration.
Measurement Method
Vacuum chambers equipped with mass spectrometers are used to quantify the gas release from a test specimen. By monitoring the pressure change over time in a known volume, researchers can calculate the outgassing rate of the sample. This measurement must account for the chamber’s own background release to ensure accurate results.
Temperature Influence
Thermal energy accelerates the release of trapped gases by increasing the diffusion rate within the material. A higher operating temperature leads to a much higher outgassing rate, requiring careful material selection for hot environments. This relationship is exponential, meaning that even a small temperature rise can significantly increase the gas load on vacuum pumps.
Mitigation Protocol
Baking materials at high temperatures under vacuum before installation is a common method for reducing gas release. This pre-treatment drives off volatile compounds, resulting in a lower outgassing rate during subsequent operation. Choosing low-outgassing materials, such as specific fluoropolymers and metals, is also essential for maintaining high vacuum integrity.
Additionally, surface treatments like electropolishing or the application of barrier coatings can further minimize the diffusion of hydrogen and other trapped gases from vacuum chamber walls.
