AVS 52nd International Symposium
    Vacuum Technology Wednesday Sessions
       Session VT-WeA

Paper VT-WeA10
Low Outgassing of Silicon-Based Coatings on Stainless Steel Surfaces for Vacuum Applications

Wednesday, November 2, 2005, 5:00 pm, Room 201

Session: Hydrogen, Outgassing, and Vacuum Systems
Presenter: D.A. Smith, Restek Corporation
Authors: D.A. Smith, Restek Corporation
M.E. Higgins, Restek Corporation
B.R.F. Kendall, Elvac Associates
Correspondent: Click to Email
Comparative tests of stainless steel vacuum chambers and components with and without silicon-based passivation coatings showed exceedingly low rates of gas evolution from the coated surfaces. A variety of approaches have been used to illustrate the low outgassing qualities of vacuum systems and vacuum components modified with an amorphous silicon deposition layer. For example, the samples are heated and cooled in turn while the outgassing rates are recorded at temperatures up to 250 degrees C. Base pressures ranged from 10-7 Torr to 2.5 x 10-10 Torr. In other experimentation, the outgassing characteristics of systems in the 10-5 to 10-7 Torr vacuum range are compared. The coatings are resilient, inert and capable of withstanding temperatures above 400 degrees C. As well as their obvious potential for reducing outgassing rates in vacuum chambers thereby allowing shorter pump-down times with smaller vacuum pump systems, they have proved useful in minimizing errors due to thermal desorption in experimental metal-envelope ionization gauges operating down to the low 10-10 Torr range.