Vacuum impregnation process produces metal-reinforced ceramics with only 3 percent void space volumes. Method may be used to produce metal-reinforced ceramics for high temperature or structural applications such as furnace supports and armor

Landingham, R. L.

English

NASA Technical Reports Server

May 1972
	 B72-10234 
.1,	 AEC-NASA TECH BRIEF _G 
AEC-NASA Tech Briefs announce new technology derived from the research and development program of the U.S. 
AEC or from AEC-NASA interagency efforts. They are issued to encourage commercial application. Tech Briefs are 
available on a subscription basis from the National Technical Information Service, Springfield, Virginia 22151. Requests 
for individual copies or questions relating to the Tech Brief program may be directed to the Technology Utilization 
Office, NASA, Code KT, Washington, D.C. 20546. 
Improved Method for Producing Metal-Reinforced Ceramics 
The problem: 
To devise a method for producing metal-rein-
forced or metal-filled ceramics which have minimal 
or no porosity. Generally metal-reinforced ceramics 
are made by sintering a compacted mixture of metal 
and ceramic powders. During the sintering process an 
oxide film forms on the metal. This film prevents the 
free flow of the molten metal and inhibits complete 
infiltration of the ceramic matrix. This method pro-
duced metal-reinforced ceramics with 10 to 15 per cent 
void space volumes. The void spaces decrease the effec-
tive cross sectional area and act as stress concentrators. 
This limits the use of metal-filled ceramics to applica-
tions not requiring high material strength and impact 
resistance. Completely filled metal-reinforced ceramics 
would be inherently stronger and more resistant to 
brittle fracture. 
The solution: 
A vacuum impregnation process produces metal-
reinforced ceramics with only 3 per cent void space 
volumes. 
How it's done: 
A ceramic powder is pressed to form a porous com-

pact of the desired shape. The compact and a quantity 
of filler metal are placed in a vacuum chamber. The
chamber is heated to a temperature above the melting 
point of the metal (generally to 1.5 times the metal 
melting temperature) and is evacuated to a pressure 
below 10-6 torr. The vacuum evaporates the oxide film
from the metal surface allowing the molten metal to

flow freely into the void spaces of the ceramic compact.

Aluminum-filled boron carbide ceramic bodies 
produced by the vacuum impregnation process exhibit
porosity of 3 per cent with an estimated aluminum con- 
tent of 35 to 40 per cent by volume. Studies of several 
metal-ceramic systems indicate that a vacuum of less 
than 10-6 torr is essential to achieve satisfactory infiltra- 
tion of the void spaces. 
The method described may be used to produce 
metal-reinforced ceramics for high temperature or struc- 
tural applications such as furnace supports and armor. 
Note:
Requests for further information may be directed 
to:
Mr. Glenn K. Ellis 
Technology Utiiztion Officer 
Office of Information Services 
U.S. Atomic Energy Commission 
Washington, D.C. 20545 
Reference: TSP72-1 0234 
Patent Status: 
Inquiries concerning rights for commerical use of 
this information may be made to: 
Mr. George H. Lee, Chief 
Chicago Patent Group 
U.S. Atomic Energy Commission 
Chicago Operations Office 
9800 South Cass Avenue 
Argonne, Illinois 60439 
Source: R.L. Landingham
Lawrence Radiation Laboratory
under contract to
Atomic Energy Commission 
(AEC-10070) 
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Administration. Neither the United States Government nor any per- 	 method, or process disclosed in this document may not infringe pri-
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Improved method for producing metal-reinforced ceramics

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