IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Vacuum Science & Technology Wednesday Sessions
       Session VST-WeA

Paper VST-WeA2
UHV Compatibility of Organic Materials

Wednesday, October 31, 2001, 2:20 pm, Room 125

Session: Gas Sorption Phenomena II
Presenter: M. Anderle, ITC-irst,, Italy
Authors: M. Anderle, ITC-irst,, Italy
C. Bellachioma, CERN, Switzerland
C. Benvenuti, CERN, Switzerland
E Broilo, CERN, Switzerland
S. Calatroni, CERN, Switzerland
P. Chiggiato, CERN, Switzerland
S. Clair, CERN, Switzerland
S. Elliott, CERN, Switzerland
J. Kenny, University of Perugia, Italy
W. Vollenberg, CERN, Switzerland
Correspondent: Click to Email
Polymers and composite materials present many attractive properties for the construction of vacuum components. They are easily formed, light, robust and electrically non conducting. However, their use for UHV applications is hindered by an important outgassing of volatile elements contained in their bulk. Furthermore,they are also prone to gas permeation when exposed to a pressure difference. An obvious improvement strategy consists in coating them with a metallic thin film to produce a hybrid material which should combine the structural properties of a polymer with the vacuum properties of a metal. Along this line,various organic materials have been coated with thin films of different metals by sputtering. It has been found that the benefits hoped for could not be fully achieved due to pin-holes in the metal coating, which are a consequence of the presence of dust grains and morphology irregularities on the surface to be coated. A quantitatve analysis of the results indicates that the outgassing through the pin-holes is enhanced by lateral gas diffusion in the polymer material. The mathematical formulation of the process and the experimental results obtained to date are presented and discussed.