Friction testing Combined With Online Monitoring
of Residual Gas

Project Funding:
Project Coordination:
AAC, Austria
Project Partners:
3 months

The perfluoro­poly­eth­ers (PFPE) are a class of fluids that are likely used as lubric­ants for space mech­an­isms. It is repor­ted that their perform­ance in the pres­ence of tribolo­gical condi­tions and in the pres­ence of vari­ous cata­lytic mater­i­als has caused seri­ous defi­cien­cies. In many cases, the PFPE fluids were extens­ively degraded and caused severe corro­sion prob­lems on metal surfaces.

AAC pod_QMS neu  CAM00041One explan­a­tion for the observed degrad­a­tion is that the fric­tion process removes the protect­ive native oxide from the metal surface and allows the fluid to contact the atom­ic­ally clean steel. A degrad­a­tion reac­tion leads to crack­ing of the organic PFPE and form­a­tion of metal fluor­ides. These fluor­ides, in turn, attack the PFPE fluid much faster than does the clean metal itself.

Tests have been made to answer the follow­ing ques­tions:

Do chem­ical reac­tions stop imme­di­ately after the tribolo­gical test is stopped, or is the process autocata­lytic going on?

Can a correl­a­tion in the resid­ual gas analysis and the qual­ity of the tribolo­gical contact be found?