A description is given of a device and process for making industrial diamonds. The device is composed of an exponential horn tapering from a large end to a small end, with a copper plate against the large end. A magnetic hammer abuts the copper plate. The copper plate and magnetic hammer function together to create a shock wave at the large end of the horn. As the wave propagates to the small end, the extreme pressure and temperature caused by the wave transforms the graphite, present in an anvil pocket at the small end, into diamonds

Estes, M. F.

Rasquin, J. R.

English

NASA Technical Reports Server

REPLY TO
ATTN OF:
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
WASHINGTON. D.C. 20546 H73-19H57
,„
Onclas
00/15 64776
TOt KSI/Scientific & Technical Information Division
Attention: Miss Winnie M. Morgan
FROM? GP/Office of Assistant General Counsel for
Patent Matters
SUBJECT: Announcement of NASA-Owned U.S. patents in STAR
In accordance with the procedures agreed upon by Code GP
and Code KSI, the attached NASA-owned U.S. Patent is being
forwarded for abstracting and announcement in NASA STAR.
The following information is provided:
U.S. patent No. :
Government or
Corporate Employee :_
Supplementary Corporate
Source (if applicable) :.
NASA Patent Case No. :
NOTE « If this patent covers an invention made by a corporate
employee of a NASA Contractor, the foilowing is applicable:
Ves
 / / No /J^ /
Pursuant to Section 305(a) of the National Aeronautics and
Space Act, the name of the Administrator of NASA appears on
the first page of the patent; however, the name of the actual
j.nventor (author) appears at the heading of column No. 1 of
the Specification, following the words "... with respect to
an invention of .
Elizabeth A. Carter
Enclosure
Copy of patent cited above
NASA-HQ
https://ntrs.nasa.gov/search.jsp?R=19730010730 2020-03-17T08:24:22+00:00Z
United States Patent
Rasquin et al.
[in 3,714,332
[45] Jan. 30, 1973
[54] PROCESS FOR MAKING DIAMONDS
[75] Inventors: John R. Rasquin, Madison; Marvin
F. Estes, Lacey Springs, both of Ala.
[73] Assignee: The United States of America as
represented by the Administrator of
the National Aeronautics and Space
Administration
[22] Filed: April 21, 1971
[21] Appl. No.: 136,086
Related U.S. Application Data
[62] Division of Ser. No. 3,418, Jan. 16, 1970, Pat. No.
3,632,242.
[52] U.S. Cl 423/446, 423/625
[51] Int. Cl COlb 31/06
[58] Field of Search 423/446, 409, 625; 425/77
[56] References Cited
UNITED STATES PATENTS
3,238,019 3/1966
3,401,019 9/1968
3,488,153 1/1970
DeCarli 423/446
Cowan et al 423/446
Bundy 423/446
FOREIGN PATENTS OR APPLICATIONS
822,363 8/1956 Great Britain 423/446
Primary Examiner—Edward J. Meros
Attorney—L. D. Woffard, Jr. et al.
[57] ABSTRACT
Apparatus and process for the production of diamond
is disclosed. The apparatus includes an exponential
horn tapering from a large end to a small end. A
copper plate is mounted against the large end of the
horn and a magnetic hammer abuts the copper plate.
The magnetic hammer and copper plate function to
create a shock wave in the exponential horn. An anvil
having a small pocket formed therein is mounted ad-
jacent to the small end of the exponential horn so that
the small end rests in the pocket. The anvil, horn and
hammer are all secured together by bolts or other
suitable means and, in operation, graphite is placed in
the anvil pocket. The magnetic hammer generates a
shock wave in the exponential horn and because of
the horn shape, which is critical, the velocity of the
shock wave is amplified and the shock wave energy
concentrated so that all of the energy in the shock
wave arrives simultaneously at the small end of the
horn. This energy is transferred to the graphite in the
anvil pocket and results in pressure and temperature
levels that causes the graphite to be transformed, in
part at least, to diamonds.
4 Claims, 3 Drawing Figures
/TJ3-JW7
PATENTED JAN30 1973 3,714,332
14
YS////////////////A
ui
a:(T
o
o
300/4 Sec.
FIG. I TIME (T)
FIG. 2
JOHN R. RASQUIN
MARVIN F. ESTES
INVENTORS
28 30
F I G . 3 BY
ATTORNEY
3,714,332
1 2
PROCESS FOR MAKING DIAMONDS To date, diamonds of gem quality have not been
This application is a division of application Ser. No. made, but synthesized industrial diamonds have been
3,418 filed Jan. 16, 1970, now U. S. Pat. No. found superior to natural diamonds for use as a grit in
3,632,242. polishing compounds. This is because the synthetic
r,™ „ .»,,,^»,^.«», 5 diamonds are single crystals, roughly octahedral inORIGIN OF THE INVENTION
 shape wUh many *cutjg edges ,* myakjng grft from
The invention described herein was made by an em- naturally occurring diamonds it is necessary to crush
ployee of the United States Government and may be the diamonds and this crushing operation results in
manufactured and used by or for the Government for many elongated slivers and flats which reduce the effi-
governmental purposes without the payment of any ' ciency of the grit produced.
royalties thereon or therefor. A primary object of this invention is to provide a sim-
plified technique and apparatus for the production of
BACKGROUND OF THE INVENTION industrial grade synthetic diamonds. Synthetic
1 Field of the Invention 15 diamonds are produced by the application of tremen-
The invention relates to the art of making industrial dous heat and pressure to carbon materials, but the
type diamonds and in particular, the invention is a sim- equipment presently used to generate this great heat
plified technique for making such diamonds with a sim- and Pressure is very massive and expensive. The
pie, but effective apparatus. Industrial grade diamonds present jnvention can be made much simpler and
are a very important item in the American economy as 20 srnaller because it utilizes a greatly amplified shock
indicated by the fact that industrial diamonds have wave to produce the necessary pressure. Since the pres-
been classified by the United States Department of sure build-up is extremely rapid, enough heat is
Defense as a special strategic material. There are two generated by the shock along with the pressure to result
sources of industrial grade diamonds; those occurring in the Production of diamonds from graphite,
naturally and obtained by mining, and synthetic 25 The apparatus employed includes an exponential
diamonds. One application of industrial diamonds is in horn of solid hardened steel that tapers from a large
the making of diamond powder used in grinding wheels end to a smal1 e"d. A magnetic hammer is positioned
for sharpening sintered metal carbide cutting tools used adjacent the large end of the exponential horn with a
in the metal working industries and other industries c°PPer Plate portioned between the horn and mag-
wherein mass production techniques are utilized. 30 netic l«"«™«- An anvil having a small pocket substan-
Diamond powder is suspended in oil, water or grease tlallv ec»ual in size to the sma" end of the exponential
and used in polishing and lapping operations. A defi- horn is "ranged below the small end of the horn so that
ciency of these industrial diamonds could no doubt the sma11 end flts into the Pocket' Pure graphite to be
cause a serious slow down in the modern metal working „ converted into diamonds is placed in the pocket of the
industry and possibly curtail the mass production of 35 anvil and then the l^mnier, copper plate, exponential
many items. Better quality industrial diamonds are used horn and anvl1 are a" secured together by a suitable
for drills of various types ranging in size from large ones supporting frame work.
for drilling oil wells and the like to small precision type The magnetic hammer is connected to a capacitor
drills like those used by a dentist.
 40
 bank and Volta8e source that delivera an electrical
2 Discussion of Prior Art discharge in the form of a fast rising current pulse for
There have been many attempts in the past to make operating the hammer and generating a mechanical
synthetic diamonds and until recently such attempts shock wave in the exponential horn that is directed to
met with little success. It was only within the last twen- the graphite in the anvil. The shock wave generated in
ty-five or so years that synthetic diamonds have been 45 the large end of the exponential horn travels through
made successfully. Principal efforts in the past to make the norn- and due to the shape of the horn, the shock
synthetic diamonds were by J. B. Hannay and Henri wave is velocity amplified and concentrated so that
Moissan. In 1880 or thereabouts Hannay alledgedly substantially all of the energy in the shock wave arrives
made diamonds by heating a mixture of hydrocarbons, simultaneously in the small end of the horn contacting
hone oil and lithium at a red heat in sealed wrought- 50 the graphite. As a result of this, a high speed pressure
iron tubes. Thereafter around 1890 Moissan dissolved front IS aPPlled or transferred to the graphite which
sugar charcoal in molten iron and quenched the solu- generates sufficient heat and pressure therein to con-
tion in cold water to crystallize the carbon under the vert a Part of the «raPhite to diamond grit,
great internal pressures supposedly generated by con- BRIEF DESCRIPTION OF THE DRAWINGS
traction as the mass cooled. Efforts to repeat these two "
methods have not met with success. FIG. 1 is a partially cross sectioned elevational view
In 1955 the General Electric Company in Schenec- of an apparatus for practicing the invention;
tady, New York, successfully made industrial grade FIG. 2 is a chart illustrating the shape of the current
diamonds by subjecting carbonaceous materials to pulse applied to the magnetic hammer; and
pressures in excess of 1,500,000 pounds per square 60 FIG. 3 is an enlarged view illustrating the arrange-
inch and simultaneously to temperatures above rnent of the small end of the exponential horn and the
5,000°F. Industrial diamonds were made on a large graphite in the anvil pocket.
scale by 1960 and up to one-tenth of a carat was
 DETA1LED DESCRIPTION OF THE INVENTIONproduced in a single run. In this same general time ,,
frame diamonds were made by a few other firms includ- The apparatus illustrated in FIG. 1 consists of a mag-
ing the DeBeers Adamant Laboratory in Johannesburg, netic hammer 10 connected to a capacitor bank 12 and
South Africa. voltage source 14 through electrical transmission lines
3,714,332
3 4
16. The magnetic hammer has a large coil in the lower be driven apart if not held together by the supporting
end thereof (not shown) and a copper plate 18 is frame work discussed above. By utilizing an electrical
mounted in abutting relation to the lower end of the discharge in which the rise time of the current pulse ap-
magnetic hammer. The copper plate and the hammer plied to the coil is very rapid, the reaction just
are separated by a sheet of plastic material 20, mylar 5 discussed will result in the generation of a shock wave
for example, to prevent any arcing that might occur in exponential horn 22. As the shock wave travels down
between the copper plate and the magnetic hammer the horn it is velocity amplified and concentrated, due
during the operation of the apparatus. An exponential to the shape of the horn, so that all of the energy arrives
horn 22 is positioned immediately below the copper at the small end of the horn substantially simultane-
plate. Horn 22 has a large end 24 that tapers down to a ously. The shock wave then leaves the hom and enters
small end 26 that fits into a pocket 28 formed in an into the graphite. The shock wave entering the graphite
anvil 30. The horn is fabricated from extremely hard is in effect a very rapid pressure front which corn-
steel, preferably a maraging steel having a Rockwell presses and heats the graphite sufficiently to promote
hardnessof 50. ., the formation of diamonds from the graphite.
The curvature of horn surface 23 is determined by In tests conducted with the apparatus, a small shock
the equation y=ceal where x and y are customary points wave was first generated to pack the graphite in the
on a plane defined by two coordinate axes, c is a con- anvil pocket and then a second shock wave was used to
stant, e is the transcendal number used as the base of produce the diamonds.
the system of natural logarithms, and a represents a 20 Several test runs were made with the apparatus using
constant. The shape of the horn must exactly duplicate different voltages. The capacitor bank employed had a
that shape which is obtained when the above equation capacity of 360 microfarads. The energy applied to the
is, by appropriate mathematical manipulations, rotated apparatus from the capacitor bank can be determined
about the jt-axis to obtain a body of revolution. This by the equation J = % CV* where J is the energy in
shape is critical and it has been found, as will be 25 joules, C is the capacitance in farads and V is the volt-
discussed hereafter, that even small variations in shape age applied to the capacitor bank. The graphite was
will result in a loss of efficiency in transmitting and con- packed in each test run by a 1,000 volt discharge and
centrating the energy of the shock wave generated in then a larger voltage was applied. When 3,000 volts
the large end of the horn. When diamonds are to be were used to charge the capacitor bank only yellow
made, pure graphite 32 is positioned in the pocket un- 30 diamonds were produced. However, a 4,000 volt
derneath the small end of the horn. discharge resulted in diamonds that were a brighter yel-
The apparatus is held together by means of two low and at 5,000 volts clear diamonds were produced,
plates, lower plate 34 and upper plate 36, the upper In the test using 5,000 volts a portion of the small end
plate having a hole 38 formed in the center thereof for . of the exponential horn was broken away. The horn
passage of electrical transmission lines from the mag- was placed in a lath and smoothed up so that it ap-
netic hammer. The two plates are secured together by a proached its original shape. However, subsequent tests
plurality of elongated rods 40 and 42 which are employing high voltages resulted only in a low yield of
threaded at each end to accept nuts 44. Any desired yellow diamonds. This leads to the conclusion that the
number of elongated rods could be used to assemble
 4Q shape of the exponential horn is critical,
the apparatus, four being used in the apparatus shown The apparatus described herein could be utilized to
and in the actual model successfully tested. make other crystalline materials by replacing the gra-
The operation of the device is as follows: assuming phite with other materials. For example, sapphire could
that the apparatus has been assembled in the manner be made from aluminum oxide (Al,).
shown in FIG. 1 and graphite has been placed in the 45 What is claimed is:
pocket of the anvil. The capacitor bank is charged from 1. A method of making diamonds comprising the
the voltage source and an electrical discharge current steps of:
pulse having characteristics like that illustrated in the confining a predetermined amount of pure graphite
chart of FIG. 2, is applied to the coil (not shown) of the in a pocket in an anvil, and
magnetic hammer. The useful portion of the pulse or 50 directing a pressure front into the graphite by posi-
wave is the first 75 microseconds. The coil is positioned tioning an exponential horn having a large end and
so as to be adjacent the copper plate. Magnetic ham- a small end, the shape of said horn being deter-
mers are known devices and one such hammer which is mined by the equation y=ce"*, so that the small
very similar to that used in this apparatus is described end of the horn is in contact with the graphite and
in U. S. Pat. No. 3,360,972 issued on Jan. 2, 1968. The 55 generating a shock wave in the large end of the
discharge from the capacitor bank flows through the horn that is velocity amplified and concentrated so
coil in the magnetic hammer generating an intense that all of the energy in the shock wave arrives
magnetic field thereabouts. The magnetic field simultaneously at the end of the horn in contact
generated by the coil in the magnetic hammer induces with the graphite whereby a pressure front is trans-
powerful eddy currents in copper plate 18 that are op- 60 ferred to the graphite that compresses and heats
posite in direction to the current in the coil of the mag- the graphite to a level that promotes the formation
netic hammer. The eddy currents also generate a strong of diamonds.
magnetic field and the magnetic field developed by the 2. The method recited in claim 1 which further in-
eddy currents in the copper plate is such that it reacts eludes the step of actuating a magnetic hammer to
against the magnetic field generated by the coil in the generate the shock wave in the horn,
magnetic hammer. In effect the magnetic hammer and 3. A method of synthesizing diamonds from graphite
copper plate tend to be driven apart and would in fact comprising the step of:
3,714,332
confining a quantity of graphite in a pocket in an an-
vil,
positioning a tapered exponential horn having a large
end and a small end, the shape of said horn being
determined by the equation y=ce", so that the
small end thereof contacts the graphite,
generating a first shock wave in the large end of the
horn that travels through the horn and is velocity
amplified and concentrated thereby to transmit a
pressure front to the graphite for settling the gra-
phite in the anvil pocket,
10
generating a second and more intense shock wave in
the large end of the horn that travels through the
horn and is velocity amplified and concentrated
thereby to transmit a second pressure front to the
graphite that compresses and heats the graphite to
a level that promotes the formation of diamonds.
4. The method recited in claim 3 wherein a magnetic
hammer is used to generate a shock wave in the ex-
ponential horn.
15
20
25
30
35
40
45
50
55
60
65


Process for making diamonds

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server