Measurement of Outgassing Rates of Steels

Area of Science:

• Materials Science
• Vacuum Technology
• Surface Science

Background:

• Steels are vital for vacuum systems due to their mechanical, corrosion, and vacuum properties.
• Low outgassing rates are essential for high and ultrahigh vacuum applications.
• Material manufacturing and pretreatment significantly influence steel outgassing rates.

Purpose of the Study:

• To detail the experimental protocol for the rate-of-pressure rise (RoR) method.
• To measure the outgassing rates of stainless steel and mild steel.
• To evaluate the effect of heat pretreatment on reducing steel outgassing.

Main Methods:

• Detailed description of the design and execution of the RoR method.
• Utilized a spinning rotor gauge to minimize measurement errors.
• Measured outgassing rates of steel samples before and after heat pretreatment.

Main Results:

• The RoR method enables routine measurement of extremely low outgassing rates (10^-11 Pa m^3 s^-1 m^-2).
• Heat pretreatment was effective in reducing the outgassing rates of both stainless and mild steels.
• The method is applicable to relatively small material samples.

Conclusions:

• The RoR method is a reliable technique for measuring hydrogen outgassing from steels in vacuum applications.
• Heat pretreatment is a viable strategy for enhancing the vacuum properties of common steels.
• Accurate outgassing rate measurement is critical for optimizing vacuum system performance.