Adhesion and Transfer of Polytetrafluoroethylene to Tungsten Studied by Field Ion Microscopy.
Abstract
Mechanical contacts between polytetrafluoroethylene (PT FE) and tungsten field ion tips were made in situ in the field ion microscope. Both load and force of adhesion were measured for varying contact times and for clean and contaminated tungsten tips. Strong adhesion between the PTFE and clean tungsten was observed at contact times greater than 2-1/2 min (forces of adhesion were greater than three times the load). For times less than 2-1/2 min, the force of adhesion was immeasurably small. The increase in adhesion with contact time after 2-1/2 min can be attributed to the increase in true contact area by creep of PTFE. No adhesion was measurable at long contact times with contaminated tungsten tips. Neon field ion micrographs taken after the contacts show many linear and branched arrays which appear to represent PTFE that remains adhered to the surface even at the high electric fields required for imaging.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1972
- Accession Number
- ADA307403
Entities
People
- Donald H. Buckley
- William A. Brainard
Organizations
- Glenn Research Center