Diffusion bonding method does not affect the mechanical properties of steel nor the strength of Teflon. It alleviates problems of adhesive outgassing, radiation damage, and delamination

Lalacona, F. P.

English

NASA Technical Reports Server

July 1969	 Brief 69-10237 
NASA TECH BRIEF	
-it 
NASA Tech Briefs are issued to summarize specific innovations derived from the U.S. space program, 
to encourage their commercial application. Copies are available to the public at 15 cents each 
from the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia 22151. 
Diffusion Bond Method of Joining Steel and a TFE-Bronze Composite 
The problem: 
To join a TFE-bronze composite and 4340 steel of 
Rc 39-41 in a time/temperature relationship that 
would neither affect the mechanical properties of the 
steel, nor the strength of the teflon. The TFE-bronze 
composite is to be the dry lubricant for gears of the 
steel which must operate in the hostile environment 
of space. Previous methods have involved adhesive 
bonding which has been less than satisfactory due to 
adhesive outgassing, radiation damage, and frequent
press, brought up to heat (580°F) and pressure (2500 
psi) for 15-to-20 minutes and allowed to cool to room 
temperature. 
Notes: 
I. This method, while offering a superior product, 
involves only 1-1/2 hours time in process whereas 
the use of adhesives takes approximately 26 hours 
(setup time and adhesive curing). 
2. The method shows promise in the field of dry 
lubrication for other than aerospace applications. 
3. No further documentation is available. 
4. Technical questions may be directed to: 
Technology Utilization Officer 
Marshall Space Flight Center 
Huntsville, Alabama 35812 
Reference: B69-10237 
Patent status: 
Inquiries about obtaining rights for the commercial 
use of this invention may be made to NASA, Code GP, 
Washington, D.C. 20546.
Source: Felix P. Lalacona
Marshall Space Flight Center 
(M FS-20482) 
•	 delamination during final machining of the gears. 
The solution: 
A diffusion bonding method that results in a product 
that is freed of outgassing and radiation problems by 
means of a diffuser at the TFE-steel interface. 
How it's done: 
Relatively standard procedures are used, with the 
exception of the interspaced diffuser. The parts to be 
joined are cleaned with methyl alcohol and the metal 
interfaces are copper flashed after which a coat of flux 
is treated with fine-mesh oxygen-free copper granules. 
The parts are then placed in a straightforward bonding
Category 03 
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Aeronautics and Space Administration. Neither the United States	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States	 will be free from privately owned rights.
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Diffusion bond method of joining steel and a TFE-bronze composite

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