Shock wave transmitted through a solid exponential horn generates heat and pressure to convert part of a charge of graphite to diamonds. The shock wave is generated in the apparatus by a complex of magnetic fields and eddy currents

Estes, M. F.

Rasquin, J. R.

English

NASA Technical Reports Server

Capacitor 
[Bank	 I 
Voltage 1 Source 
;oil Within 
lastic Sheet 
:opper Plate 
II End of Horn 
)hite in Pocket
B 
Time
nd of Horn 
)f Graphite 
Anvil 
September 1970
	 CORRECTED COPY
	 Brief 70-10513 
NASA TECH BRIEF 
Manned Spacecraft Center	 . 
NASA Tech Briefs announce new technology derived from the U.S. space program. 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. 
Synthesis of Diamonds 
Clear or yellow industrial-grade diamonds can be 
synthesized from graphite with a novel and relatively 
light apparatus. 
A copper plate rests over the large (upper) end of
of graphite in the pocket; the heat and pressure thus 
generated convert at least part of the graphite to dia-
monds. The hammer, copper plate, horn, and anvil 
are assembled within a bolted frame. 
A
	
C 
Sections of Apparatus (A). Small End of Horn (B), and the Shape of the Current Pulse (C). 
a solid exponential horn made of hardened steel 
(Fig. 1A). A magnetic hammer, abutting the copper 
plate, functions with the plate to create a downward 
shock wave in the horn. Through the small, (bottom) 
end of the horn, fitting snugly in a small pocket in 
an anvil (Fig. 1B), the shock is transmitted to a charge
A bank of capacitors delivers a fast-rising current 
pulse (Fig. 1C) to the coil in the bottom of the mag-
netic hammer; the prototype's bank had a capacity 
of60F.Thecoil is separated from the copper plate 
by a plastic sheet to prevent arcing. The resultant 
complex of magnetic field, eddy currents, and mag-
I .....4 .... 
This document was prepared under the sponsorship of the National 	 Governmtht assumes any liability resulting from the use of the, 
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.
https://ntrs.nasa.gov/search.jsp?R=19700000495 2020-03-17T00:34:20+00:00Z
netic field, in and around the coil and the plate, tends Note: 
to drive apart the hammer and the plate (which are Requests for further information may be directed to: 
constrained within the frame). The shock wave travel-
-	 Technology Utilization Officer 
ing down the horn is velocity amplified and concen Code A&TS TU 
trated (because of the critical shape of the horn) so Marshall Space Flight Center 
that all energy arrives at the small end substantially
-	 -.	 Huntsville, Alabama 35812 
simultaneously. The shock wave entering the graphite Reference	 TSP70 10513 
and forming diamonds is in effect a very rapid pres- Patent status: sure front. .	 . 
The voltage applied to the capacitor bank
	 was
-	 Inquiries about obtaining rights for the commercial 
. 
varied. A 10007V charge was used to tamp the graphite use of this invention may be made to: 
in the pocket. Subsequent charges of 3000, 4000, and Patent Counsel 
5000 V produced yellow,, brighter yellow, and clear Mail Code A&TS-PAT. 
diamonds respectively. George C. Marshall Space Flight Center 
Marshall Space Flight Center, Alabama 35812 
Source: J. R. Rasquin and M. F. Estes 
Marshall Space Flight Center 
(MFS-20698) 
Brief 70-10513, Category 08


Synthesis of diamonds

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