US3647331A

US3647331A - Ultrahigh pressure-temperature apparatus

Info

Publication number: US3647331A
Application number: US18143A
Authority: US
Inventors: Tatsuo Kuratomi
Original assignee: Individual
Current assignee: Individual
Priority date: 1969-03-10
Filing date: 1970-03-10
Publication date: 1972-03-07
Anticipated expiration: 1989-03-07
Also published as: JPS503025B1; DE2011010A1; US3727028A

Abstract

An improvement in ultrahigh pressure-temperature apparatus in which adiabatic, electrically nonconductive, thermostable cylinders are utilized to protect the outer portions of the apparatus from the pressures and temperatures generated within the innermost parts of the apparatus.

Description

D United States Patent 1151 3,647,33 1

Kuratomi 1 Mar. 7, 1972 [54] ULTRAHIGH PRESSURE- 3,096,544 7/1963 Lunblad ..18/D1G. 26 TEMPERATURE APPARATUS 3,201,828 8/1965 Fryklund ...18/DlG. 26 3,061,877 11/1962 Custers et al. ,..l8/DlG. 26 [721 f; ga i g; 3,383,737 5/1968 Greger ...18/DIG. 26 gas 3,407,445 10/1968 Strong ...1s/1)1c. 26 [22] Filed: Mar. 10, 1970 3,249,964 5/1966 Shaler ...18/DlG. 26 2,941,252 6/1960 Bovenkerk ...18/D1G. 26 [21] 18143 3,313,004 4/1967 Vahldiek et al ..l8/DlG. 26

[30] Foreign Application Priority Data Primary ExaminerJ. Spencer Overholser Assistant Examiner-Donald M. Gurley M .1 ,1 69 J ..4417548 at 0 9 apan I Attorney-K. W. Brownell [52] U.S.Cl. ..425/77, 425/DlG. 26, 425/78,

425/406 ABS IRACT [51] Int. Cl. ..B30b 11/00, B30b 11/32 An im provement 1n ultrah1gh pressure-temperature apparatus 0t 26, R, R in adiabatic electrically nonconductive thermostable cylinders are utilized to protect the outer portions of the ap [56] References Cited paratus from the pressures and temperatures generated within UNITED STATES PATENTS the innermost parts Of the apparatus.

3,350,743 1 1/ 1967 lshizuka ..18/DlG. 26 3 Claims, 3 Drawing Figures PATENTEDMAR 71972 3,647,331

FIG!

I PIP/0R ART NTOR. TATJUO K TOM/ ULTRAI-IIGH PRESSURE-TEMPERATURE APPARATUS BACKGROUND OF THE INVENTION This invention relates to ultra-higbpressure-temperature apparatus.

Ultra-high-pressure-temperature apparatus capable of producing and maintaining pressures of the order of 40,000 to 100,000 atmospheres and temperatures of the order of 1,000 to 2,500 C. is desirable to effect, control and study reactions occurring under these conditions. The reactions of various materials subjected to such pressures and temperatures can be employed for research study purposes or to obtain physical and chemical changes which desirably alter the characteristics of the materials. For example, new compounds are known to be formed by subjecting old materials to very high pressures. Ultra-high-pressure-temperature apparatus is also useful for studying the changes in phase of various materials which occur at very high pressures, or for studying the compressibility or electrical, optical or magnetic properties of various materials. An example of a change occurring under these conditions which is of considerable practical utility is the catalytic conversion of nondiamond carbon to the diamond form.

Prior art high-pressure-temperature apparatus of this type comprises generally (1) a pair of opposed punch assemblies, each of the punch assemblies terminating in a tapered electrically conductive piston; (2) means for exerting pressure on the punch assemblies, whereby an electrically conductive object positioned between the opposed pistons can be subjected to high pressure; (3) a lateral pressure-resisting annulus, positioned between the opposed pistons and provided with a substantially central aperture circumferentially surrounding the object to be subjected to high pressure, the annulus having a pressure-resisting inner wall surface; (4) means for passing electrical current through the pistons and the object to be subjected to high pressure, whereby to produce a high temperature within the object simultaneously with the high pressure; and (5) thermal and electrical insulating gaskets positioned in the aperture of the lateral pressure-resisting annulus and circumferentially surrounding the tapered pistons.

A typical prior art apparatus is illustrated in FIG. 1, wherein a lateral pressure-resisting annulus 4 having apressure-resisting inner wall surface 5 is shown surrounding object 7. Opposed tapered electrically conductive pistons 6 and 6 are urged toward object 7 by conventional means (not shown) to produce high pressure in object 7. Thermally and electrically insulating gaskets 8 and 8 are provided to separate pistons 6 and 6 from annulus 4, but not from object 7. Electricity is then passed through piston 6, object 7 and piston 6, thus heating object 7 by internal resistance heating. Annulus 4 is strengthened and reinforced with several layers of steel rings.

Apparatus of this type is frequently capable of pressures in excess of 80,000 atmospheres and temperatures in excess of 2,000 C., and further details of its construction and operation are described in the prior art, for example US. Pat. No. 2,941,248. Such apparatus is subject to the disadvantage, however, that the pressure-resisting annulus 4 and pistons 6 and 6 bear much of the pressure and heat of the reaction within object 7, with the result that these parts are subject to fracture and frequently need replacement. Furthermore, it is difficult to enlarge any given annulus 4 to accommodate a larger object 7, inasmuch as the inner walls 5 of cylinder 4 are tapered toward its center.

SUMMARY OF THE INVENTION It is, therefor, an object of this invention to provide a new and improved high-pressure-temperature apparatus of the type described which overcomes the above-noted problems of the prior art. These and other objects are achieved by providing the pressure-resisting inner wall surface of the pressure-resisting annulus with a vertical cylindrical shape, and in combination therewith, an adiabatic, electrically nonconductive, thermostable hollow cylinder positioned within the aperture of the lateral pressure-resisting annulus and circumferentially surrounding the object to be subjected to high pressure (e.g., a reaction chamber for the conversion of nondiamond carbonaceous material to diamond). The outer portions of the apparatus are thus protected from the pressures and temperatures within the innermost parts of the apparatus. Further details and preferred embodiments are indicated below.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional schematic diagram of the central portion of conventional high-pressure-temperature apparatus as described above.

FIG. 2 is a sectional schematic diagram of the central portion of apparatus according to the present invention.

FIG. 3 is a sectional view of the apparatus of FIG. 2, taken along line 3-3 ofFIG. 2.

DETAILED DESCRIPTION Referring now to FIGS. 2 and 3 of the drawings, the apparatus of the present invention will now be described in detail.

Lateral pressure-resisting annulus l 1 having a vertical cylindrical shape for its pressure-resisting inner wall surface surrounds circumferentially the object 20 to be subjected to high pressure. Materials which can be used for annulus 11 include ultrahard alloys, high-speed steel and die steel; these materials themselves are known in the art. Above and below object 20 are opposed punch assemblies (not shown), terminating in tapered electrically conductive pistons 12 and 12'. It should be noted that references herein to above," below, lateral"and the like are merely indicative of orientation when the apparatus is arranged with the pistons 12 and 12' in a vertical configuration, and the apparatus need not be so arranged. This designation is convenient, however, in indicating the relative orientation of the various parts of the apparatus herein described. Materials which can be used for pistons 12 and 12' include die steels and ultrahard alloys such as cemented tungsten carbide. One such alloy which is commercially available contains 94 percent tungsten carbide and 6 percent cobalt.

Within the aperture of lateral pressure-resisting annulus 11 and circumferentially surrounding object 20 is an adiabatic, electrically nonconductive, thermostable hollow cylinder 15. Preferred materials for cylinder 15 include thorium oxide, zirconium oxide, hafnium oxide and mixtures thereof. In order that temperatures of 2,500 C. can be generated within object 20, the material for hollow cylinder 15 must have a melting point of at least 2,600 C. and be adiabatic and electrically nonconductive. Materials with sufficiently high melting points and electrical resistivities include the following:

Material Melting Point Thorium Oxide 3,300" C. Magnesium Oxide 2,825 C. Zirconium Oxide 2,700" C. Calcium Oxide 2,630 C. Hafnium Oxide 2,800 C.

Of these materials, however, calcium oxide and magnesium oxide are not preferred because of their comparatively high thermal conductivities. Calcium oxide has the further disadvantage of reacting with carbon at temperatures above 2,000 C. to form calcium carbide. The carbonization reaction advances rapidly and continuously, whereas the carbides of thorium and zirconium, for example, form thin filmy protective coatings on the inner face of hollow cylinder 15, so that further carbonization does not occur.

In a preferred embodiment of this invention, there is provided a pair of adiabatic thermostable discs 19 and 19', disc 19 being positioned above object 20, between object 20 and piston 12; and disc 19' being positioned below object 20, between object 20 and piston 12'. Discs 19 and 19' are of such diameter, however, as to allow the passage of electrical current from one piston to the other piston'through object 20.

This is.preferably accomplished by providing (1) a pair of electrically

conductive rings

17 and 17 surrounding discs 19 and 19', respectively, and in electrical contact withpistons l2 and 12', respectively; and (2) a pair of electrically conductive discs 18 and 18', disc 18 being positioned above object 20, between object 20 and disc 19; and disc 18 being positioned below object 20, between object 20 and disc 19'. Discs l8 and 18 are simultaneously in electrical contact with rings 17 and 17', respectively, on the one hand, and object 20 on the other. Thus electrical current can pass from piston 12 to ring 17 to disc 18 to object 20 to disc 18 to ring 17 to piston 12, while pistons 12 and 12' are shielded by adiabatic

thermostable discs

19 and 19 from the heat and pressure generated in object 20. Preferred materials for adiabatic

thermostable discs

19 and 19 include thorium oxide, zirconium oxide, hafnium oxide, and mixtures thereof.

A still more preferred embodiment of this invention includes a second adiabatic, electrically nonconductive, thermostable, hollow cylinder 14 positioned within the aperture of the lateral pressurerresisting annulus 1 l, and circumferentially surrounding (l) the first adiabatic, electrically nonconductive, thermostable, hollow cylinder 15; (2) the adiabatic, thermostable discs 19 and 19'; (3) the electrically conductive rings 17 and 17'; (4) the electrically conductive discs 18 and 18'; and (5) the object 20 to be subjected to high pressure, Preferred materials for adiabatic, electrically nonconductive, thermostable, hollow cylinder 14 include zirconium oxide, pyrophyllite, and mixtures thereof.

A still more preferred embodiment of this invention includes a metallic hollow cylinder 13, positioned within the aperture of the lateral pressure-resisting annulus 11 and circumferentially surrounding the second adiabatic, electrically nonconductive, thermostable, hollow cylinder 14. Cylinder 13 should be of a metallic material of great hardness and tenacity so as to reduce the high pressures-generated within the apparatus (by urging pistons 12 and 12' towards object 20), and thereby subject annulus 11 to less stress than would otherwise be the case. Thus annulus 11 is able to maintain its hardness and tenacity without being melted or worsened in quality by the full heat and pressures generated within object 20. Preferred materials for cylinder 13 include ultrahard alloys, high-speed steel, die steel and ceramic-metallic (cermet) alloys.

By the use of cylindrical shapes for the pressure-resisting inner wall surface of pressure-resisting annulus 11 and for cylinders l3, l4 and 15, these innermost parts which bear the greatest heat and pressure of the apparatus can easily be replaced, if need be. The cylindrical shape also aids in the transmission of pressures from

pistons

12 and 12 to object 20.

Thermal and electrical insulating gaskets l6 and 16, preferably of pyrophyllite, surround pistons 12 and 12', respectively, to complete the portion of the apparatus shown.

I claim:

1. In a high-pressure-temperature apparatus for subjecting an object to high pressure, comprising: (a) a pair of opposed,

tapered, electrically conductive pistons; (b)a lateral, pressure-resisting annulus, positioned between the opposed pistons and coaxial therewith, provided with a substantially central aperture circumferentially surrounding the object to be subjected to high pressure, the annulus having a pressureresisting inner wall surface; and (c) a thermal and electrical insulating gasket positioned in the aperture of the lateral pressure-resisting annulus and circumferentially surrounding the tapered pistons, the invention which comprises the provision of a vertical cylindrical shape for the pressure-resisting inner wall surface of the pressure-resisting annulus, and in combination therewith l) a first adiabatic, electrically nonconductive, thermostable, hollow cylinder, positioned within the aperture of the lateral, pressure-resisting annulus, and circumferentially surrounding the object to be subjected to high pres sure, said first adiabatic, electrically nonconductive, thermostable, hollow cylinder consisting essentially of thorium oxide, zirconium oxide, hafnium oxide, or mixtures thereof; (2) a pair of adiabatic, thermostable discs, one disc being positioned above and one disc being positioned below the object to be subjected to high pressure, between said object and the opposed pistons; said discs being of such diameter as to allow the passage of electrical current from one piston to the other piston through the object to be subjected to high pressure, said adiabatic, therrnostable discs consisting essentially of thorium oxide, zirconium oxide, hafnium oxide, or mixtures thereof; (3) a pair of electrically conductive rings, each ring surrounding one of the adiabatic thermostable discs and being in electrical contact with one of the opposed pistons; (4) a pair of electrically conductive discs, one electrically conductive disc being positioned above and one electrically conductive disc being positioned below the object to be subjected to high pressure, between said object and the adiabatic therrnostable discs, each of said electrically conductive discs being electrically in contact with one of the electrically conductive rings and with the object to be subjected to high pressure; (5) a second adiabatic, electrically nonconductive, thermostable, hollow cylinder, positioned within the aperture of the lateral pressure resisting annulus and circumferentially surrounding (a) the first adiabatic, electrically nonconductive, thermostable, hollow cylinder; (b) the adiabatic, thermostable discs; (c) the electrically conductive rings; (d) the electrically conductive discs; and (e) the object to be subjected to high pressure; said second adiabatic, electrically nonconductive, thermostable, hollow cylinder consisting essentially of zirconium oxide, pyrophyllite, or mixtures thereof; and (6) a metallic hollow cylinder, positioned within the aperture of the lateral pressure-resisting annulus and circumferentially surrounding the second adiabatic, electrically nonconductive, therrnostable, hollow cylinder.

2. The invention of claim 1 wherein the first adiabatic, electrically nonconductive, thermostable, hollow cylinder consists essentially of hafnium oxide.

3. The invention of claim 1 wherein the adiabatic, thermostable discs consist essentially of hafnium oxide.

Claims

1. In a high-pressure-temperature apparatus for subjecting an object to high pressure, comprising: (a) a pair of opposed, tapered, electrically conductive pistons; (b) a lateral, pressure-resisting annulus, positioned between the opposed pistons and coaxial therewith, provided with a substantially central aperture circumferentially surrounding the object to be subjected to high pressure, the annulus having a pressureresisting inner wall surface; and (c) a thermal and electrical insulating gasket positioned in the aperture of the lateral pressure-resisting annulus and circumferentially surrounding the tapered pistons, the invention which comprises the provision of a vertical cylindrical shape for the pressure-resisting inner wall surface of the pressure-resisting annulus, and in combination therewith (1) a first adiabatic, electrically nonconductive, thermostable, hollow cylinder, positioned within the aperture of the lateral, pressure-resisting annulus, and circumferentially surrounding the object to be subjected to high pressure, said first adiabatic, electrically nonconductive, thermostable, hollow cylinder consisting essentially of thorium oxide, zirconium oxide, hafnium oxide, or mixtures thereof; (2) a pair of adiabatic, thermostable discs, one disc being positioned above and one disc being positioned below the object to be subjected to high pressure, between said object and the opposed pistons; said discs being of such diameter as to allow the passage of electrical current from one piston to the other piston through the object to be subjected to high pressure, said adiabatic, thermostable discs consisting essentially of thorium oxide, zirconium oxide, hafnium oxide, or mixtures thereof; (3) a pair of electrically conductive rings, each ring surrounding one of the adiabatic thermostable discs and being in electrical contact with one of the opposed pistons; (4) a pair of electrically conductive discs, one electrically conductive disc being positioned above and one electrically conductive disc being positioned below the object to be subjected to high pressure, between said object and the adiabatic thermostable discs, each of said electrically conductive discs being electrically in contact with one of the electrically conductive rings and with the object to be subjected to high pressure; (5) a second adiabatic, electrically nonconductive, thermostable, hollow cylinder, positioned within the aperture of the lateral pressure resisting annulus and circumferentially surrounding (a) the first adiabatic, electrically nonconductive, thermostable, hollow cylinder; (b) the adiabatic, thermostable discs; (c) the electrically conductive rings; (d) the electrically conductive discs; and (e) the object to be subjected to high pressure; said second adiabatic, electrically nonconductive, thermostable, hollow cylinder consisting essentially of zirconium oxide, pyrophyllite, or mixtures thereof; and (6) a metallic hollow cylinder, positioned within the aperture of the lateral pressureresisting annulus and circumferentially surrounding the second adiabatic, electrically nonconductive, thermostable, hollow cylinder.