+ View the NASA Portal NEPP Website Search   Powered By Google Your Path: Home » Parts » Parts Experts   Parts Publications Index   Parts Publications by Area of Emphasis   Parts Links Parts Experts   Parts Manufacturers   Focused Parts Issue Portals & NPSL   GSFC Parts Engineering Resources and Contacts   GSFC Specifications and Qualified Parts List Directory   Search         BACK to Publication List Chlorine contamination diffusion in silicones File Name: Chlorine contamination diffusion in silicones.doc | Date Submitted: 03/05/02   File Size: 791KB Document Author Alexander Teverovsky - ateverov@pop300.gsfc.nasa.gov GSFC on-site Contractor Phone: 301 286-9691 | FAX: None On File [Additional User Information] Download "Chlorine contamination diffusion in silicones" (791KB) Now.   Description: In this study the diffusion coefficient of chlorine contamination in silicones has been estimated using two techniques.   Abstract: Using the diffusion cell technique and autoclave tests of aluminum corrosion test structures it is shown that silicones are much more permeable for volatile chlorine containing contaminants than for nonvolatile.  The estimated diffusion coefficient at 121 °C is less than (4 – 7) ´10-11 cm2/s for nonvolatile chlorides (NaCl) and (4-9)´10-9 cm2/s for volatile ones (HCl).  The activation energy of diffusion is estimated to be 0.3-0.4 eV in the first case and approximately 0.1 eV in the second.  Due to the different permeability for volatile and nonvolatile chlorides, silicones provide protection in moisture environments as conformal coatings on boards and are much less effective as buffer layers in plastic encapsulated devices   Related Project(s): EPAC (Electronic Packaging) EPAR (Electronic Parts)   Related Area(s) of Emphasis: Development of Innovative Qualification Methods     NEPP Program Manager: Michael J. Sampson Responsible NASA Official: Michael J. Sampson Webmaster: Carl M. Szabo, Jr.       Last Updated: November 29, 2007