Differential thermal analysis of a lunar soil simulant, 'Minnesota Lunar Simulant-1' (MLS-1) was performed. The MLS-1 was tested in as-received form (in glass form) and with another silica. The silica addition was seen to depress nucleation events which lead to a better glass former

Setzer, A.

Tucker, D.

English

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NASA
Technical
Memorandum
NASA TM-103563
i
l
#
P
(NASA- TM- 103563)
ANALYSIS OF LUNAR
12 p
DIFFERENTIAL THERMAL
SOIL SI_ULANT (iIASA)
CSCL 03B
"3/vl
DIFFERENTIAL THERMAL ANALYSIS OF LUNAR
SOIL SIMULANT
N92-15951
Unclas
0061945
By D. Tucker, and A. Setzer
Materials and Processes Laboratory
Science and Engineering Directorate
December 1991
National Aeronautics and
Space Administration
George C. Marshall Space Flight Center
MSFC- Form 3190 (Rev. May 1983)
https://ntrs.nasa.gov/search.jsp?R=19920006733 2020-03-17T14:19:32+00:00Z

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1. AGENCY USE ONLY (Leave blank) 2. REPORT DATE 3. REPORT TYPE AND DA'TES COVERED
December 1991 Technical Memorandum
4. TITLE AND SUBTITLE 15. FUNDING NUMBERS
Differential Thermal Analysis of Lunar Soil Simulant
6. AUTHOR(S)
D. Tucker and A. Setzer
7. PERFORMINGORGANIZATIONAME(S)AND ADDRESS(ES)
George C. Marshall Space Flight Center
Marshall Space Flight Center, Alabama 35812
9. SPONSORING/MONITORINGA ENCYNAME(S)AND ADDRESS(ES)
National Aeronautics and Space Administration
Washington, DC 20546
8. PERFORMING ORGANIZATION
REPORT NUMBER
10. SPONSORING/MONITORING
AGENCY REPORT NUMBER
NASA TM-I03563
11. SUPPLEMENTARYNOTES
Prepared by Materials and Processes Laboratory, Science and Engineering Directorate
lZa. DISTRIBUTION / AVAILABILITY STATEMENT
Unclassified - Unlimited
12b. DISTRIBUTION CODE
13. ABSTRACT (Maximum 200 words)
Differential thermal analysis of lunar soil simulant known as "Minnesota Lunar Simulant-l"
(MLS-1) was performed. The MLS-1 was tested in the as-received form, in glass form, and with
additional silica. The silica addition was seen to depress nucleation events which leads to a better
glass former.
14. SUBJECT TERMS
Differential Thermal Analysis (DTA), Lunar Simulant, Fiberglass
17. SECURITY CLASSIFICATION
OF REPORT
Unclassified
18. SECURITY CLASSIFICATION
OF THIS PAGE
Unclassified
19. SECURITY CLASSIFICATION
OF ABSTRACT
Unclassified
15. NUMBER OF PAGES
12
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NTIS
; 20. LIMITATION OF ABSTRACT
NSN 7540-01-280-5500 Standard Form 298 (Rev 2-89)

TABLE OF CONTENTS
INTRODUCTION ........................................................................................................................
EXPERIMENTAL AND RESULTS ..........................................................................................
DISCUSSION AND CONCLUSIONS .......................................................................................
REFERENCES ...........................................................................................................................
Page
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PRECEDING PAGE BLANK NOT FILMED
LIST OF ILLUSTRATIONS
Figure
1.
2.
3.
4.
5.
Title
MLS-1 DTA curve ...................................................................................................
MLS-1 glass ...............................................................................................................
E-glass DTA curve ...................................................................................................
MLS-1 55-percent SiO2 .........................................................................................
MLS-1 55-percent SiO2 glass ................................................................................
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iv
TECHNICAL MEMORANDUM
DIFFERENTIAL THERMAL ANALYSIS OF LUNAR SOIL SIMULANT
INTRODUCTION
The use of lunar regolith for the production of structural materials could greatly reduce the
cost for construction and long-term habitation of a lunar colony. One lunar product, fiberglass (both
discontinuous and continuous forms), promises ease of manufacture and wide applicability.1 Con-
tinuous fiberglass can be utilized as reinforcement in structural composites, including pressure
vessels, glass cables, and woven thermal insulation. Discontinuous (chopped or blown) could be
used as insulation or composite reinforcement. The chemistry of lunar soils is similar to that of ter-
restrial basalt. 2 3 Glass fibers have been produced using a simulated lunar basalt. 4 One aspect of
glass fiber production which is critical to fiber strength is suppression of critical nuclei formation dur-
ing the drawing process. It has been shown that the presence of even a small amount of crystalline
material can be deleterious to basalt fiber strength. 5 One method of investigating crystallization is to
use differential thermal analysis (DTA). Crystallization events will show up as exotherms on a DTA
plot. As part of an ongoing study, DTA was used to test some of the thermal characteristics of a
lunar simulant which is being used to produce continuous glass fiber.
EXPERIMENTAL AND RESULTS
The simulant used in this study is known as Minnesota lunar simulant-1 (MLS-1). This
material was provided by the University of Minnesota Space Sciences Laboratory. The major ele-
ment chemistry of MLS-1 is shown in table 1 along with a comparison with Apollo sample 10084.
DTA was used to characterize the melting point of MLS-1, as well as the crystallization
behavior of glass made from MLS-1. The simulant was heated to 1,100 °C at a rate of 5 °C/min and
then to 1,450 °C at a rate of 1 °C/min. Figure 1 shows the resulting curve from this DTA run. An
endotherm is exhibited at 1,200 °C which indicates the MLS-1 melting point. The melting point was
verified by heating a sample to 1,200 °C in a tube furnace and visually observing the phase transi-
tion.
For crystallization studies, MLS-1 was heated in a platinum crucible to 1,450 °C in a box fur-
nace for 24 hours, then poured onto an aluminum plate to form a glass. The glass was then crushed
using a mortar and pestle to facilitate loading into the DTA sample holder. The glass sample was
then heated to 1,300 °C at a rate of 5 °C/min. Figure 2 is a DTA curve of the MLS-1 glass. The first
crystallization exotherm appears at approximately 350 °C and is followed by other exotherms up to
1,000 °C. Figure 3 is a DTA heating curve of E-glass produced for comparison. Note the absence of
exotherms in this curve.
The MLS-1 was next doped with silica such that the weight percent of silica was raised from
44 to 55 percent. This was done to aid the glass formation process of MLS-1. The DTA curve for this
material is shown in figure 4. One can see that the melting point was lowered to 1,150 °C along with
the appearance of two small exotherms at approximately 800 °C and 1,000 °C. These exotherms may
be due to reactions of the silica with constituents in the MLS-1. This material was also made into a
glassand thenheatedin the DTA. Figure 5 showstheDTA curve for the silica dopedMLS-1 glass.
It can be seen that the crystallization exotherms between 200 °C and 1,000 °C are no longer present.
However, there is an exotherm present at approximately 1,280 °C.
DISCUSSION AND CONCLUSIONS
In order for a normally crystalline material to be spun into a glass fiber, it is necessary to
rapidly cool or quench the fiber from at or above the melting point to near room temperature such that
recrystallization does not occur. This quench must be extremely rapid, e.g., on the order of hundreds
of °C/s, to avoid nucleation events. A true glass, however, may be cooled at slower rates and avoid
crystallization. This means that a glass fiber can be formed over a wide range of temperatures,
known as the working range of the glass. The materials tested in this study, although capable of
forming glass, are not good glass formers. This is evidenced by the DTA results which showed that
nucleation occurred readily in the MSL-1 glass. Doping the MLS-1 with silica did suppress the low
temperature crystallization events, however, a higher temperature exotherm occurred, which is most
likely due to sintering of silica.
Thus, it will be necessary to provide a rapid quench during fiber formation to obtain suitable
fiber characteristics (e.g., tensile strength and flexibility). This is particularly important for fiber
diameters of less than 20 micrometers, since recrystallized material would serve as comparatively
large, high-stress sites for failure.
Further work is planned in order to determine the origin of the exotherms noted in figure 2.
This would entail producing standards by mixing known amounts of silica with titania, iron oxide, and
alumina and performing DTA analyses on these compounds. Reactions between these materials
should provide insight into what is occurring in the MLS-1 glass.
It can be concluded from this work that MLS-1, though capable of forming a glass fiber, is not
a good glass former. Doping with silica will be necessary to reduce the crystallization events and
increase the working range of the glass.
|
Table 1. Major element chemistry of MLS-1 and Apollo 10084.
Element
(%) Average Maximum Minimum 10084
Be 1.00 1.22 0.87
Zn 122 141 97
Cu 445 706 214
Sc 50 61 41
Co 64 84 53
Pb 18 20 10
Ni 97 163 53
Th 14 15 13
Cr 173 366 89
Rb 4 10 1
V 761 952 506
Zr 47 113 19
Y 27 28 13
Ba 95 117 62
Sr 212 253 173
p/m Average Maximom Minimum
SiO2 43.86 45.90 41.70 42.55
TiO2 6.32 7.43 4.82 7.71
A1203 13.68 15.60 11.76 13.47
F e O 13.40 14.40 12.00 15.16
Fe203 2.60 4.10 0.90
MgO 6.68 8.44 5.57 7.98
MnO 0.198 0.218 0.182 0.208
CaO 10.13 11.48 9.04 11.99
Na20 2.12 2.27 1.97 0.445
K20 0.281 0.348 0.167 0.147
P205 0.20 0.45 0.02 0.140
CO2 0.0015 0.0018 0.0014
-I
0
ii
@
"I"
2
0
-2
-3
-4
"s
i
L
iiiiiiiiiIIIIIL Ii
" /
.5 ¸
0 300 600 900 1200 1500
Temperature (C)
Figure 1. MLS-I DTA curve.
4
O
U.
e
//
........... • .... %,, ......... J
_i I
-2.... : i_X ........I_:
. \.,.,, _
-4 _ ............................
-6 ......................................................................
-8
0 300 600 900 1200
Temperature (C)
Figure 2. MLS'I glass.
1500
O@
"I-
4
3 _
2 _ = = = .....
-2
-3
0 300 600 900 1200 1500
Temperature (C)
Figure 3. E-glass DTA curve.
v
O
i
i1
o
-2
-4
k_
i\ I -----'-_
i 1 • _1 .... i
\
_r
_6 ¸
0 300 600 900 1200 1500
Temperature (C)
Figure 4. MLS-1 55-percent SiO2.
5
A0
g
@
4
2
0
-2
-4
0 300 600 900 1200 1500
Temperature (C)
Figure 5. MLS-1 55-percent SiO2 glass.
REFERENCES
1. Criswell, D.R.: "Lunar Materials." Second Princeton Conference on Space Manufacturing
Facilities--Space Colonies, May 7-9, 1975.
2. McKenzie, J.D., and Claridge, R.C.: "Glass and Ceramics From Lunar Materials." AIAA
Proceedings, 1979, pp. 135-140.
3. Alton, J.H., Galindo, C. Jr., and Watts, L.A.: "Guide to Using Lunar Soil and Simulants for
Experimentation." Lunar Bases and Space Activities of the 21st Century, 1985, pp. 497-506.
4. Chemical and Engineering News, June 4, 1973, p. 49; April 29, 1974, p. 29.
5. Subramanian, R.V., Yang, T.J.Y., and Austin, H.F.: "'Reinforcement of Polymers by Basalt
Fibers." SAMPE Quarterly, June 1977, pp. 1-10.
7
APPROVAL
DIFFERENTIAL THERMAL ANALYSIS OF LUNAR SOIL SIMULANT
By D. Tucker and A. Setzer
The information in this report has been reviewed for technical content. Review of any
information concerning Department of Defense or nuclear energy activities or programs has been
made by the MSFC Security Classification Officer. This report, in its entirety, has been determined
to be unclassified.
Director, Matertgls and Processes Laboratory
";_'U.S. GOVERNMENT PRINTING OFFICE 1992--631-060/60024


Differential thermal analysis of lunar soil simulant

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