Optimized zirconia foam ceramic body shows promise for use as a thermal insulation material. The insulating media displays low density and thermal conductivity, good thermal shock resistance, high melting point, and mechanical strength

Blocker, E. W.

Paul, R. D.

English

NASA Technical Reports Server

November 1967	 Brief 67-10441 
NASA TECH BRIEF
	
A Ali 
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. 
Newly Developed Foam Ceramic Body Shows Promise as

Thermal Insulation Material at 3000° F 
.
.
The advances made in the area of aerospace propul-
sion systems have created urgent requirements for 
inorganic insulation materials with the inherent capa-
bility of insulating at temperatures of +3000'F. The 
present generation of high specific impulse engines 
generates severe radiative and convective heating en-
velopes as well as high vibratory stresses. These con-
ditions dictate the use of inorganic insulators that 
must fulfill specific requirements such as high melt-
ing temperatures, insulating efficiency, oxidation 
resistance, and high mechanical strength. These gen-
eral requirements may be used to define the proper-
ties of an ideal insulating material for aerospace 
vehicles. The insulating media must display low den-
sity and thermal conductivity, good thermal shock 
resistance, high melting point, and mechanical 
strength. 
A program was initiated with the specific objective 
of developing alkali metal peroxide and superoxide 
blown ceramic foams with lowered thermal conduc-
tivity. Cast ceramic bodies, composed of chemically-
blown and chemically-bonded zirconia foams, were 
also formulated and evaluated for their physical and 
mechanical, thermal, and optical properties. 
The results of the program are summarized as fol-
lows: An optimized foam ceramic body, designated 
Z76 (ZrP207), has been developed and evaluated. 
Study of the gross properties shows a uniform pore 
distribution and a narrow range of pore sizes. The 
as-cast surface of the body exhibited a smooth (matte) 
skin that was hard, and penetrated by small diameter 
holes connected to internal pores. Cut surfaces of the 
body show hemispherical depressions that appear as 
closed cells. An interesting phenomenon was the ar-
rangement of internal pores into a repeating hexag-
onal pattern.
The Z76 properties that have been evaluated are:

	
I. Density range	 0.96-1.80 g/cc 
2. Flexural strength 
(Modulus of 
rupture)	 237 psi 
3. Compressive strength 731 psi 
4. Thermal shock 
	
resistance	 Fair to poor 
5. Melting point	 3335° F 
6. Thermal conductivity 4.5 BTU/hr O F in/ft2 
at 1550°F 
7. Emittance 
(hemispherical) 0.78 at 317°F 
It was concluded that the Z76 foam ceramic ma-
terial developed under this program shows promise 
for use as a thermal insulation material. 
Note: 
Additional details are contained in Development 
of Alkali Metal Peroxide and Superoxide Blown 
Ceramic Foams, by E. W. Blocker and R. D. Paul, 
United Aircraft Corporation, April 5, 1966. This 
report is available from: 
Technology Utilization Officer 
Marshall Space Flight Center 
Huntsville, Alabama 35812 
Reference: B67-10441 
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: E. W. Blocker and R. D. Paul 
of United Aircraft Corporation 
under contract to 
Marshall Space Flight Center 
(M FS- l 1968)
Category 03 
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States 
Government nor any person 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 such use 
will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19670000441 2020-03-11T21:13:35+00:00Z


Newly developed foam ceramic body shows promise as thermal insulation material at 3000 deg F

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