Radiation resistant material, made of polyimide polymers and S-glass cloth, is used in ball bearing retainers for extreme environments. Material displays satisfactory wear resistance, lubricity, and stability. Results of comparative tests with fluorocarbon materials are given

Desau, P. O.

Emmons, W. F.

English

NASA Technical Reports Server

November 1970	 Brief 70-10576 
Itty CO,
AEC-NASA TECH BRIEF 
TES 
- AEC-NASA Tech Briefs announce new technology derived fróm the research and delment pogram of the U.S.AEC
-or - 
from AEC-NASA interagency efforts.Jhey are issued to encourage commercial application. Tech Briefs are available on a 
subscription basis from the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia 22151. 
Requests for individual copies or questions relating to the Tech Brief program may be directed to the Technology Utilizatin 
Division, NASA, Code UT, Washington, D.C. 20546. 
Low-Temperature Radiation-Resistant Material

for Ball-Bearing Retainers 
A new material, made of polyimide polymers and 
S-glass (alumina-silica-magnesia) cloth and developed 
in the nuclear-rocket program, may replace fiberglass-
reinforced polytetrafluoroethylene in ball-bearing 
retainers for extreme environments. The fluorocarbon 
material weakens badly at cryogenic temperatures and 
after nuclear radiation doses exceeding 10 9 erg/g. 
The new material shows satisfactory wear resistance, 
lubricity, and stability. 
The S-glass cloth is wound on a mandrel of preset 
diameter matched in size with the bearing retainer. 
The cloth is impregnated with polybenzimidazole 
(PBI), in powder-slurry form, placed between and over 
the windings. The laminate is cured in five heat cycles 
ranging from 70° to 700°F at pressure between 0 and 
100 lb/i,1 2 (gage). The cured part is machined to final 
size. 
Polybenzimidazole has greater thermal stability than 
the fluorocarbons because of a greater degree of 
chain condensation. A major advantage in the use 
of S-glass is its freedom from elements such as boron 
that could become involved in nuclear reactions.
The following results were typical of comparative 
tests of the PBl and fluorocarbon materials: (1) while 
irradiation increased PBI's strength by 15%, it reduced 
the latter's by 81%; (2) while the PB!'s rate of wear 
was slightly inferior at from 8500 to 12,200 rpm in 
liquid hydrogen, it was still acceptable; (3) after irra-
diation to 2 x 1010: erg/g, a retainer made of PBl 
was tested successfully for 3 hr at 24,000 rpm. 
Note: 
Requests for further information may be directed to: 
Technology Utilization Officer 
AEC-NASA Space Nuclear Propulsion Office 
U.S. Atomic Energy Commission 
Washington, D.C. 20545 
Reference: B70-10576 
Patent status: 
No patent action is contemplated by AEC or NASA.

Source: P. o. Desau and W. F. Emmons of

Aerojet-General Corp.

under contract to

Space Nuclear Propulsion Office

(NUC-10058) 
Category 04 
This document was prepared under the sponsorship of the Atomic 
Energy Commission and/or the National Aeronautics and Space 
Administration. Neither the United States Government nor any per-
son acting on behalf of the United States Government assumes any
liability resulting from the use of the information contained in this 
document, or warrants that the use of any information, apparatus, 
method, or process disclosed in this document may not infringe pri-
vately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19700000558 2020-03-17T00:39:19+00:00Z


Low-temperature radiation-resistant material for ball-bearing retainers

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server