NASA 

Technical 

Memorandum 

NASA TM - 86569 

ELECTRICAL PROPERTIES OF Al-In-Sn ALLOYS 

DIRECTIONALLY SOLIDIFIED IN HIGH AND 

LOW GRAVITATIONAL FIELDS 

Center Director's Discretionary Fund Final Report 

By P. A. Curreri, M. K. Wu, J. R. Ashburn, and 

W. K. Kaukler 

Space Science Laboratory 

Science and Engineering Directorate 

October 1986 

(HASA-TB-8650 '3) ELECTElCAL FICfEbTIES OF N87- 16900 Al-In-Sn ALLOkS CIHEC3ICNA1LY SCLIDIPiED IN 

hJGkI AND LCW 6BAVITATFChAL EIELCS Center 

Cirector's Discretionary Fund Einal Report 

(bASA) 21 p CSCL 11F G3/2t, 43842 

Unclas 

NASA 

National Aeronautics and 

Space Administration 

George C. Marshall Space Flight Center 

MSFC - Form 3190 (Rev. May 1983) 
NASA TM -86569 

AND 

I 

Electrical Properties of Al-In-Sn Alloys 

Directionally Solidified in High and Low Gravitational 

Fields - Center Director's Discretionary Fund Final Report 

I 

5. DATE 

October 1986 

6. PERFORMING ORGANIZATION CODE 

7. AUTHOR(S) P. A. Curreri, M. K. Wu,* 

J. R. Ashburn," and W. F. Kaukler** 

9. PERFORMING ORGANIZATION NAME AND ADDRESS 

1 

15. SUPPLEMENTARY NOTES 

Prepared by Space Science Laboratory , Science and Engineering Directorate. 

**Department of Chemistry, The University of Alabama in Huntsville. 

*Department of Physics, The University of Alabama in Huntsville. 

16. ABSTRACT 

8. PERFORMING ORGAN1 ZATION REPOR r # 

10. WORK UNIT NO. 

Al-In-Sn alloys have been directionally solidified in the NASA KC- 135 aircraft 

which flies a series of parabolas to generate high (high-g) and low gravity (low-g) 

forces parallel to the longitudinal growth axis. 

sections can be identified which were solidified in high-g and low-g. Measurements 

of the electronic properties of the samples reveal that: 

low-g sections is larger (about a factor of 10) than that of the high-g sections; 

(2) the low-g sections behave conductively like a semi-metal, while the high-g 

sections are essentially metallic; and (3) both high-g and low-g sections are 

superconducting but the superconducting transition temperature of the low- g 

sections is 1 K higher than that of the high-g sections. 

Thus, for a given sample, successive 

(1) the resistivity of the 

George C. Marshall Space Flight Center 

Marshall Space Flight Center, Alabama 35812 

12. SPONSORING AGENCY NAME AND ADDRESS 

National Aeronautics and Space Administration 

Washington, D. C. 20546 

17. KEY WORDS 18. DISTRIBUTION STATEMENT 

11. CONTRACT OR GRANT NO. 

'13. TYPE OF REPOR;' & PERIOD COVERED 

Technical Memorandum 

1.;. SPONSORING AGENCY CODE 

Alloy Directional Solidification, I 

19. SECURITY CLASSIF. (d thli rmpe) 20. SECURITY CLASSIF. (of thlm page) 21. NO. OF PAGES 

Unclassified Unclassified 20 

TECHNICAL REPORT STANDARD TITLE PAGE 

1. REPORT NO. f 2. GOVERNMENT ACCESSION NO. 13. RECIPIENT'S CATALOG NO. 

MSFC - Form 3292 (my 1969) 

F~~ =le by ~~ti~d ~~~u~d Information Service. Springfieid. Virginia 221 

22. PRICE 

NTIS 

Low Gravity, Al-In-Sn, 

Immiscible Alloy Solidification, 

Electronic Properties 

Unclassified - Unlimited 
ACKNOWLEDGMENTS 

The authors wish to thank M. H. RkCay for her invaluable contribution to the 

solidification study and J. Coston for the WDX analysis and the SEM work. We would 

also like to thank G. Workman, G. Smith, and D. Warden for their careful preparation 

of the samples. This work was supported by the Marshall Space Flight Center Director's Discretionary Fund and the Research Institute of the University of Alabama in 

Huntsville. 
TABLE OF CONTENTS 

Page 

INTRODUCTION .............................................................. 1 

EXPERIMENTALS .............................................................. 1 

RESULTS ..................................................................... 2 

DISCUSSION ................................................................. 3 

REFERENCES ................................................................. 6 

iii 
LIST OF ILLUSTRATIONS 

Figure 

1. 

2. 

3. 

4. 

5. 

6. 

7. 

8. 

Title 

Photomicrograph of Al- 18.9In- 14.6Sn along the longitudinal 

growth axis showing the microstructure of the sample up to 

the third low-g zone ................................................ 

Normalized resistance R ( Tc) /R( 300 K) as a function of temperature 

of Al- 18.9In- 14.6Sn sections solidified under different levels of 

acceleration ......................................................... 

Schematic plot illustrating the characteristic behavior of 

resistance as a function of temperature for semi-metal and 

for metal with superconducting transition at low temperature.. ....... 

Electrical resistance and magnetic susceptibility at low 

temperature of Al- 18.9In- 14.6Sn solidified under different 

levels of acceleration ................................................ 

Tc , R( 300 K) /R ( Tc) , and gravitational acceleration along the 

longitudinal growth axis as a function of sample position ............. 

Detail of the electrical resistance as a function of temperature 

near the superconducting transition temperature, Tc, at two 

measuring currents.................................................. 

Schematic plot showing the proposed model for the current 

conducting path for sample solidified in low g and in 

high g .............................................................. 

Superconducting transition temperature plotted versus Sn 

concentration and the phase diagram of In-Sn alloys 

(Tc data taken from Reference 9) .................................... 

Page 

8 

9 

10 

11 

12 

13 

14 

15 

iv 
TECHNICAL MEMORANDUM 

ELECTRICAL PROPERTIES OF Al-In-Sn ALLOYS DIRECTIONALLY 

SOLIDIFIED IN HIGH AND LOW GRAVITATIONAL FIELDS 

Center Director's Discretionary Fund Final Report 

INTRODUCTION 

The feasibility of producing high volume fraction immiscible alloys with finely 

dispersed microstructure by low-gravity solidification was demonstrated in 1974 r 11 . Ga-Bi samples solidified in free fall, with a gravity level of 10-4 g (g = 980 cm/s2), had 

much finer microstructure than the control samples solidified in normal gravity. It 

was also found that the electrical properties of the low-gravity solidified materials 

were significantly different from those of the control samples solidified under the 

same conditions except at one gravity [ 21. The potential to synthesize in space a 

new class of electronic materials was suggested by these initial experiments. However, extensive studies along this line in space are limited due to high cost and 

limited access to orbital experimentation facilities. 

In an attempt to gain more insight into the low-gravity processing on the 

material properties of immiscible alloys, we decided to carry out a systematic study 

of materials solidified directionally in a Bridgman furnace on NASA's KC-135 aircraft. 

The advantages of using KC-135 are that it is relatively inexpensive, has a short 

turnaround time, and provides the capability when combined with unidirectional 

solidification of having in one sample a series of identifiable sections grown in low-g 

or high-g [3-51. The material chosen in this study is the ternary Al-In-Sn alloy [6]. 

This alloy was chosen because the A1-In binary has been well studied and the addition of Sn to the A1-In binary would alter the interphase interfacial energy and the 

morphology of the solid-liquid interface and therefore the cast structure. 

would then help to identify the role of interphase interfacial energies during solidification with varying g levels. 

AI-In, Al-Sn, and In-Sn alloys have been extensively studied. Therefore, an extension of the study to the ternary system is a logical choice. 

studied in this report is the A1-18.9In-14.6Sn in weight percent. 

This study 

In addition, the electrical properties of the binary 

The specific material 

EXPERIMENTALS 

The Al-In-Sn alloys were directionally solidified in a high temperature Bridgmantype furnace with a water-cooled quench block. 

process samples during maneuvers of NASA's KC-135 aircraft. The aircraft flies a 

series of parabolas during which the onboard experiment experiences up to 30 s of 

Therefore, a sample which is being solidified experiences a repetitive sequence of 

low-g and high-g forces parallel to the longitudinal growth axis. The acceleration 

during processing is monitored by three accelerometers mounted on the furnace on 

orthogonal axes with one parallel to the longitudinal growth axis. For a typical 

maneuver during low-g, the acceleration on all axes averages below 10-2 g [ 71. 

During pullout and climb, the high-g acceleration parallel to the sample longitudinal 

The furnace system was used to 

. low gravity and up to 1.5 min of pullout and climb with up to 1.7 g acceleration. 
axis reaches 1.7 g while the acceleration on the other axes is less than 0.15 g. 

growth rate for the A1-18In-14Sn sample was 0.5 cm per minute. This results in 

low-g sections of about 2.5 mm alternating with high-g sections of about 7.5 mm. 

The samples were positioned relative to the thermal gradient of the furnace to allow 

about 2 cm of the sample to remain unmolten prior to directional solidification. 

The 

The solidified sample (8 cm long x 5 mm dia.) was first cut and mounted longitudinally, then polished using successively smaller grit. 

polished sample was examined under an optical microscope in reflected light to determine the location of the boundary where directional solidification was initiated. 

Growth rate and accelerometer data were then used to correlate position on the 

sample with gravitational acceleration during solidification. 

Al- 18.9In- 14.6Sn flight sample for which properties data are reported here is shown 

in Figure 1. Samples of different gravity level were sectioned using a diamond saw, 

and smaller samples of dimension 1 mm x 1 mm x 3 mm were cut and used for electrical and magnetic properties measurements. The conventional d. c. or a. c. fourprobe method was used for the electrical resistivity measurements. 

bridge operated at 40 Hz was used to measure the magnetic susceptibility. Transverse sections of different gravity level were mounted and polished for scanning 

electron microscope (SEM) study. 

employed to determine the chemical composition of the samples. 

The metallographically 

A photomicrograph of 

An a.c. inductance 

Wavelength dispersive x-ray (WDX) analysis was 

RESULTS 

Typical resistance, R, of samples solidified at different gravity levels is shown 

in Figure 2 as a function of temperature. It can be seen that the resistance of low-g 

samples is less temperature-dependent . of the samples measured which includes the sample section prior to directional solidification and In-Sn alloys of two selected compositions. The resistance ratio [ defined 

as R(300 K)/R(Tc) where Tc is the onset temperature of the superconducting transition] of high-g samples is larger than that of low-g samples. 

room temperature resistivity of the low-g samples is about a factor of 10 larger than 

that of the high-g samples. 

function of temperature for typical semi-metal and metal with a superconducting 

transition at low temperature. 

teristic curves in Figure 3 clearly indicate that the low-g sample behaves more like a 

semi-metal while the high-g sample is essentially metallic. 

Table 1 summarizes the electrical properties 

On the other hand, the 

Figure 3 is a schematic plot showing resistance as a 

Results given in Figure 2 in comparison to the characAll samples studied become superconducting with an onset temperature ranging 

from 7.8 K to 6.3 K. 

and magnetic susceptibility at low temperature for a high- and low-g sections. 

average transition width is 3 K, showing the inhomogeneous character of our material. 

Since our main interest lies in the comparison of the characteristics of the low-g and 

high-g samples, we have taken the onset temperature of the transition as Tc. 

resistance ratio, and the gravitational acceleration parallel to the growth axis during 

solidification as plotted versus sample position are shown in Figure 5. 

Figure 4 shows the temperature dependence of the resistance 

The 

Tc, 

In Figure 6, we have shown an example of the detailed resistive behavior of a 

sample (Section 7) at low temperature. 

both low-g and high-g samples in the temperature regime right before the complete 

superconducting transition. 

denly rises before the complete transition. 

the measuring currents. 

An unusual electrical anomaly is observed for 

The resistance first decreases on cooling and then sudThe magnitude of the anomaly depends on 

A measuring current larger than 10 mA is found to 

2 
completely suppress the anomaly, leaving only the lower temperature superconducting 

transition (where T, is defined). An external magnetic field of 300 G is also found 

to suppress the observed anomaly. It should be noted that such an anomaly is not 

characteristic of an inhomogeneous sample with broad superconducting transition. 

addition, such an anomaly was not observed in the ground processed In-Sn samples. 

In 

Microstructure and chemical composition analyses of the samples have been performed using a SEM fitted with a WDX analyzer. 

the samples consist of particles of 10 to 50 vm in size embedded in the aluminum 

matrix. 

dark and light particles in the light field SEN;. 

dark phase is about one-third of the particles. 

entirely of In and Sn. 

wt.% Sn and the Sn content does not change with g-level during solidification. 

the other hand, the Sn concentration of the light phase of the particles does appear 

to vary with gravity level. 

while its counterpart in high-g is mainly In-Sn with 75 wt.% Sn. A summary of the 

results is also given in Table 1. 

variation in overall composition as function of gravity level. 

The micrographs clearly show that 

It is found that there are two different phases in these particles, viewed as 

The apparent volume fraction of the 

These particles are made almost 

The dark phase of the particles consists of In-Sn with 25 

On 

The low-g light particle is mainly In-Sn with 25 wt.% Sn, 

WDX measurements at 200X magnification show little 

DISCUSSION 

The results given in Table 1 and Figure 5 clearly demonstrate that the accelerations during solidification greatly affect the electrical properties of the sample. 

The electrical behavior evidenced by small overall resistance ratio indicates that the 

samples studied are indeed inhomogeneous or polyphase. 

dominated by the scattering of electrons by the dispersion of second phase which is 

the precipitated In-Sn embedded in the aluminum matrix if we consider the connecting 

path of the electron is the aluminum matrix. 

of an alloy depend on its particle size and the interface between particles [ 81. 

Smaller particles will lead to an increase in the surface-to-volume ratio with a subsequent increase in electron scattering and interface effects. 

resistance ratio and the larger room temperature resistivity of the low-g sample over 

those of the high-g samples suggest that samples solidified at low-g may consist of 

finely dispersed particles. Unfortunately, we do not see any clear difference in 

particle size between low- g and high-g samples from photomicrographs. 

that the conducting path may be different for samples solidified at different gravity 

level. 

Their resistivities are 

It is known that the electrical properties 

The relatively smaller 

This suggests 

Based on the WDX composition analysis, it can be inferred from the phase 

diagram that low-g samples contain mainly f3 phase (25 wt.% Sn) In-Sn particles, 

while the high-g samples consist of small portions of 6 phase particles randomly 

distributed in the larger y phase (75 wt.% Sn) particles. 

unreasonable to assume that for the high-g samples, the connectivity of the conducting 

path is through the aluminum matrix, and for the low-g samples, it is through the 

precipitated In-Sn particles. This model is shown schematically in Figure 7. The 

observation of the resistive behavior of the ground processed In-Sn samples, which 

is similar to that of the low-g samples but different from that of the high-g samples, 

seems to support such an assumption. 

then the smaller dark particles and the larger light particles for the low-g and high-g 

samples, respectively. 

one-third that of the light particles. 

Therefore, it is not 

With this model, the scattering centers are 

As mentioned earlier, the size of the dark particles is about 

This corresponds to a factor of 10 reduction 

3 
in surface-to-volume [8] ratio for the dark particles. 

resistivity in low-g samples is then expected. This is consistent with the observed 

difference in room temperature resistivity and resistance ratio between the low- g and 

high-g samples. A photomicrograph study of the deep etched sample indeed shows 

that the precipitated particles are more dense in the low-g sections than in the high-g 

sections, but attempts to quantitatively verify the difference in the connectivity of 

the In-Sn phase have been thus far inconclusive. 

A factor of 10 increase in 

The superconductivity observed is attributed to the presence of the In-Sn 

phase. 

It was found that Tc of the quenched samples varies from 7.8 K to 5.5 K with Sn 

content [9]. 

while y phase alloys have Tc on the order of 6 K. 

perature of In-Sn alloys as a function of Sn content along with the In-Sn binary 

phase diagram is shown in Figure 8. 

low-g samples have Tc about one degree higher than that of the high-g samples, and 

our hypothesis based on WDX analysis that the low-g particles are essentially f3 phase 

while high-g sections contain mainly y phase particles. 

Superconductivity of the In-Sn system has been extensively studied [ 9- 111 . 

Peak Tc of 7.8 K occurs at the f3 phase with composition of 30 wt. % Sn, 

Superconducting transition temThis is consistent with our observations that 

The resistive anomaly observed at low temperature is rather unusual. The 

It suggests that the sample 

dependence of the anomaly on transport currents and external magnetic fields indicates that the anomaly is superconducting in origin. 

undergoes a normal + superconducting -+ normal -+ superconducting transition. It 

is known that a granular superconductor, in which the superconducting grains are 

coated with an insulating layer or imbedded in an insulating matrix, may exhibit 

reentrant superconductivity [ 12-14]. 

sample, it is very possible that there exist small superconducting grains coated with 

thin insulating film that have relatively larger Tc than that of the major In-Sn 

particles. 

temperature decreases, superconductivity appears in the small grains and phase 

matching between grains is established through Josephson coupling, resulting in the 

decrease in resistance. Upon further cooling, decoupling between the superconducting 

grains occurs when the resistance of the insulating film reaches a certain value and 

results in an increase in resistance. However, at a lower temperature where the 

major In- Sn particles become superconducting, a complete transition occurs through 

the connectivity of these particles. The facts that a magnetic field of 300 G and a 

current density of 1 A /cm2 completely suppressed the anomaly indicate that the 

superconductivity of these small grains is a weak coupling type. 

whether the exact origin of this superconductivity is due to the In-Sn micrograins or 

some unidentified phases (such as interfacial effects [ 151 between particles) is 

unknown. The absence of the anomaly in the ground processed In-Sn samples 

suggests that the presence of aluminum may play an important role. 

noted that such a "tricriticle transition" has been observed in an Au/Ge alternating 

ultra-thin layered film [ 161 . 

In view of the inhomogeneous nature of our 

The observed resistive behavior can then be understood as follows: as 

At this moment, 

It should be 

The observation of a preferential phase formation at different gravity of the 

Al-In-Sn system is surprising. 

being pursued, 

diagram is underway. 

More detailed compositional study of the samples is 

A careful analysis of the microstructure in relation to the phase 

The results will be presented in a separate paper. 

In conclusion, we have studied the ternary, Al- 18.9In-14.6Sn directionally 

Electrical properties measurements of the samples 

(1) Low-g samples behave more like a 

solidified in NASA KC- 135 aircraft. 

solidified at different g levels show that: 

4 
semi-metal while high-g samples are essenwy metallic. 

samples are superconducting but Tc of 1o.w-g samples is 1 K higher than that of 

high-g samples. 

observed in the samples studied. 

(2) Both low-g and high-g 

(3) A resistive anomaly attributed to reentrant superconductivity is 

I 

5 
REFERENCES 

1. 

2. 

3. 

4. 

5. 

6. 

7. 

8. 

9. 

10. 

11. 

12. 

13. 

14. 

15. 

16. 

6 

Reger, J. L. and Yates, I. C. , Jr. : 

D. C., 1974. 

AIAA Paper No. 74-207, Washington, 

Lacy, L. L. and Otto, G. H.: 

1974. 

AIAA Paper No. 74-208, Washington, D. C., 

Johnston, M. H., Curreri, P. A., Parr, R. A., and Alter, W. S. : Metall. 

Trans., Vol. 16A, 1985, p. 1683. 

Stefanescu, D. M., Curreri, P. A., and Fiske, M. R. : Metall. Trans. , Vol. 

17A, 1986, p. 1121. 

Lee, J. E., McCay, M. H., and Curreri, P. A.: Metall. Trans., A, in press, 

1986. 

(a) Campbell, A. N., Buchanan, L. B., Kuzmak, J. M., and Tuxworth, R. H. : 

J. Am. Chem. SOC., Vol. 74, 1952, p. 1952. (b) Grugel, R. N. and Hellawell, 

A.: Metall. Trans., Vol. 12A, 1981, p. 669. (c) Derby, B., Camel, D., and 

Favier, J. J.: J. Crystal Growth, Vol. 65, 1983, p. 280. 

Hendrix, J. C., Curreri, P. A., and Stefanescu, D. M.: AFS Trans., Vol. 

92, 1984, p. 435. 

Maeden, G. T. : Electrical Resistance of Metals, Plenum Press, New York, 1965. 

Wernick, J. H. and Matthias, B. T.: J. Chem. Phys., Vol. 34, 1961, p. 2194. 

Merriamm, M. F. and Von Nerzen, M.: Phys. Rev., Vol. 131, 1963, p. 637. 

Bartram, S. F., Moffatt, W. G., and Roberts, B. W.: J. Less-Common Metals, 

Vol. 62, 1978, p. 9. 

Abeles, B.: Phys. Rev., Vol. B15, 1977, p. 2828. 

Ambegaokar, V. and Baratoff, A.: Phys. Rev. Lett., Vol. 10, 1963, p. 486. 

Itskovish, I. F. and Shekhter, R. I.: Fiz. Nizk. Temp., Vol. 7, 1981, p. 

863. [Sov. J. Low Temp. Phys., Vol. 7, 1981, p. 4181. 

Geballe, T. H. and Chu, C. W.: Comm. Solid State Phys., Vol. 9, 1979, 

p. 115. 

Akihama, R. and Okamoto, Y. : Solid State Commun., Vol. 53, 1985, p. 655. 
TABLE 1. ELECTRICAL PROPERTIES OF Al- 18.9In- 14.6Sn 

Sn Content 

(wt . %) 

Sample No. ~(273 K) (VQ-cm) p(273 K)/p(Tc) Tc (K) (LPP) (DPP) G 

1 13.5 38.3 6.5 24 19 1 

2 121.2 1.54 7.4 26 25 Low 

3- 1 9.3 25.4 6.7 72 19 High 

3- 2 103.2 7.9 7.1 22 19 Low 

4 19.1 15.2 6.5 68 21 High 

5 123.6 5.6 7.8 26 19 Low 

6 14.9 4.7 6.7 50 21 High 

7- 1 731.7 0.78 7.3 21 26 Low 

7- 2 395.2 1.8 7.4 21 26 Low 

8 15.5 13.9 6.5 73 26 High 

9 

A1 

46.7 2.4 7.3 - - Low 

1.17 4.2 lo3 1.17 

In7sSn25 (6) 56.1 2.15 7.1 

1n25Sn75 (Y) 70.1 2.57 6.4 

LPP: Light Phase Particles 

DPP: Dark Phase Particles 

G: Level of Acceleration 

. 

7 
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3 

0 

.rl 

4 

rl 

a, 

k 

I 8 
1 .o 

0.8 

0.6 

0.4 

0.2 

0 

0 100 200 

TEMPERATURE (IC) 

300 

Figure 2. Normalized resistance R(Tc)/R(300 K) as a function of temperature of 

Al- 18.9In- 14.6Sn sections solidified under different levels of acceleration. 

9 
n 

Iai 

K 

0 50 100 150 200 250 300 

TEMPERATURE (K) 

Figure 3. Schematic plot illustrating the characteristic behavior of 

resistance as a function of temperature for semi-metal and for 

metal with superconducting transition at low temperature. 
. 

. 

1 .o 

0.8 

- 

!Z 0.6 2 

3 

ai 

a 

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X 

0.4 

0.2 

0 

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1 .o 

0.8 

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4 

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0 

0 

0 

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- 

0.6 E 

0.4 

0.2 

0 

Figure 4. Electrical resistance and magnetic susceptibility at low temperature 

of Al- 18.9In- 14.6Sn solidified under different levels of acceleration. 

11 
8 

*c 7 

(K) 

6 

1 

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0 10 20 30 40 50 

POSITION (mm) 

Figure 5. Tc, R(300 K) /R(Tc), and gravitational acceleration along 

the longitudinal growth axis as a function of sample position. 

12 
1 .o 

.97 

94 

.91 

Figure 6. 

7.1 7.2 7.3 

T(K) 

Detail of the electrical resistance as a function of temperature near 

the superconducting transition temperature, Tc, at two measuring currents. 

13 
LOW-G SAMPLE 

HIGH-G SAMPLE 

Figure 7. Schematic plot showing the proposed model for the current 

conducting path for sample solidified in low g and in high g. 
0 

0 

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15 
APPROVAL 

ELECTRICAL PROPERTIES OF Al-In-Sn ALLOYS DIRECTIONALLY 

SOLIDIFIED IN HIGH AND LOW GRAVITATIONAL FIELDS 

Center Director's Discretionary Fund Final Report 

By P. A. Curreri, M. K. Wu, J. R. Ashburn, and W. F. Kaukler 

The information in this report has been reviewed for technical content. 

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. 

Review 

I 

I Deputy Director , Space Science Laboratory 

16 * U.S. GOVERNMENT PRINTING OFF ICE 1986-730-067f40033