Accession Number : ADA310448

Title :   Reaction of Perfluoroalkylpolyethers (PFPE) with 440C Stainless Steel in Vacuum Under Sliding Conditions at Room Temperature.

Descriptive Note : Technical paper,

Corporate Author : NATIONAL AERONAUTICS AND SPACE ADMINISTRATION CLEVELAND OH LEWIS RESEARCH CEN TER

Personal Author(s) : Mori, Shigeyuki ; Morales, Wilfredo

PDF Url : ADA310448

Report Date : JAN 1989

Pagination or Media Count : 12

Abstract : Reactions of the perfluoroalkylpolyethers (PFPE) Fomblin Z25, Demnum S200, and Krytox 16256 were studied during sliding contact with stainless steel (440C) specimens under ultra-high-vacuum conditions. All three fluids reacted with the steel specimens during sliding. Fomblin, which has acetal linkages, decomposed under the sliding conditions and generated gaseous products, namely, COF2 and fluorinated carbons, which were detected by a quadruple mass spectrometer. Gaseous products were not detected for the Demnum and Krytox fluids. The amount of gaseous products from Fomblin increased with increasing sliding speed. At the end of the sliding experiments, the wear scar and the deposits on the specimens were examined by small-spot-size x-ray photo-emission spectroscopy. The oxide layer on the specimen surface was removed during sliding, and metal fluorides were formed on the worn surface. The surfaces of the wear scar and the deposits were covered with adsorbed PFPE. On the basis of these results, it was concluded that the decomposition reaction of Fomblin began when the fluid contacted the fresh metal surface formed during sliding.

Descriptors :   *VACUUM, *STAINLESS STEEL, *FLUORINATION, *FLUORINE COMPOUNDS, *SLIDING CONTACTS, VELOCITY, METALS, LAYERS, QUADRUPOLE MOMENT, CARBON, ROOM TEMPERATURE, GASES, SURFACES, OXIDES, X RAY PHOTOELECTRON SPECTROSCOPY, WEAR, FLUIDS, MASS SPECTROMETERS, LINKAGES, DECOMPOSITION, FLUORIDES, ALKYL RADICALS, ULTRAHIGH VACUUM, POLYETHERS, ACETAL RESINS.

Subject Categories : Polymer Chemistry
      Inorganic Chemistry
      Organic Chemistry
      Properties of Metals and Alloys
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE