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Tribological and microstructural comparison of HIPped PM212 and PM212/Au self-lubricating compositesThe feasibility of replacing the silver with the volumetric equivalent of gold in the chromium carbide-based self-lubricating composite PM212 (70 wt percent NiCo-Cr3C2, 15 percent BaF2/CaF2 eutectic) was studied. The new composite, PM212/Au has the following composition: 62 wt percent NiCo-Cr3C2, 25 percent Au, 13 percent BaF2/CaF2 eutectic. The silver was replaced with gold to minimize the potential reactivity of the composite with possible environmental contaminants such as sulfur. The composites were fabricated by hot isostatic pressing (HIPping) and machined into pin specimens. The pins were slid against nickel-based superalloy disks. Sliding velocities ranged from 0.27 to 10.0 m/s and temperatures from 25 to 900 C. Frictions coefficients ranged from 0.25 to 0.40 and wear factors for the pin and disk were typically low 10(exp -5) cu mm/N-m. HIPped PM212 measured fully dense, whereas PM212/Au had 15 percent residual porosity. Examination of the microstructures with optical and scanning electron microscopy revealed the presence of pores in PM212/Au that were not present in PM212. Though the exact reason for the residual porosity PM212/Au was not determined, it may be due to practice morphology differences between the gold and silver and their effect on powder metallurgy processing.
Document ID
19930029508
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Bogdanski, Michael S.
(Case Western Reserve Univ. Cleveland, OH, United States)
Sliney, Harold E.
(NASA Lewis Research Center Cleveland, OH, United States)
Dellacorte, Christopher
(NASA Lewis Research Center Cleveland, OH, United States)
Date Acquired
August 15, 2013
Publication Date
November 1, 1992
Publication Information
Publication: Lubrication Engineering
Volume: 48
Issue: 11
ISSN: 0024-7154
Subject Category
Chemistry And Materials (General)
Accession Number
93A13505
Funding Number(s)
PROJECT: RTOP 505-63-5A
CONTRACT_GRANT: DE-AI01-91CR-50306
Distribution Limits
Public
Copyright
Other

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