High pressure generation by MASS 318-90 type apparatus
MASA-K
75-0011
Kazuaki Masaki·, Hiroshi Sawamoto, Eiji Ohtani, and Mineo Kumazawa
Department of Earth Sciences. Nagoya University. Nagoya. Japan
Michihide Machida, Shin Mizukusa, and Noboru Nakayama
Government Industrial Research Institute. Nagoya. Japan
(Received 8 August 1974; and in final form, 16 September 1974)
MASS 318-90 type apparatus is developed to generate pressures up to 500 kilobar
in a volume of 7.5 mm 3• The geometry, operational mechanism, and the result of
the pressure-generating experiment are described in detail.
INTRODUCTION
A group of new mechanisms, MASS (multiple-anvil sliding
system), has been presented by one of the authors l for the
generation of high pressure. The novel mechanisms are
quite different from the ordinary ones we already know,
in the sense that the massive supported anvils displace
forwards, backwards, or laterally in association with the
sliding between anvils, and the volume of the material
surrounded by a set of anvils is reduced without any gap or
gasket between anvils.
Although the theoretical advantages of the MASS over
the other types of apparatus has been discussed, 1 no one
has sufficient experience how to utilize the new mechanisms
practically. Further, there are many different types of MASS
mechanisms, and also several different ways of driving
them. 2 Therefore, we have been making e.,--q>eriments on
the different types of mechanisms using different ways of
operation: CN5-90 in a PY3 type guide block up to TI
point3 ; CNS-90 and BS5-90 in a PY3 guide block and
OC8-90 and OB8-90 in a couple of PY3 guide blocks up
to Bi 1II-V point4; CNS-90 and BS5-60 in a tetrahedral
press up to Pb pointS; 3R8-90 in a cubic press up to Bi
II1-V point 6 ; and 318-90 in a cubic press up to GaAs
point. 7 The pressures mentioned above do not show the
technical limitation of pressure generated by each type of
MASS and by the way of driving them. The present pressure
values are restricted by the small tonnage sately applied
to the MASS through the guide blocks or the press available
for each of the particular experiments.
By accumulating the technical experiences in the practical
use of the MASS mechanisms, we came to believe that the
new mechanisms were definitely useful for scientifi.c studies
under very high pressure. Actually, high pressures up to
300-400 kilobar combined with high temperature could be
maintained for one hour. An example is the success in the
decomposition of Mg 2Si0 4 to MgO (periclase) and SiO:
(stishovite) at 330 kilbbar and lOOO°C. 8
.
The purpose of this paper is to present the mechanis~
and operation of a very practical MASS 318-90 apparatus
driven by means of a cubic press for scientific use on the
routine basis, and the results of the pressure generation up
to about 500 kilobar.
84
Rev. Sci. Instrum., Vol. 46, No.1, January 1975
THE GEOMETRY AND OPERATIOt:-lAL
MECHANISM OF MASS 318-90
The geometrical assembly of the MASS 318-90 mechanism is shown in Fig. 1. The two truncated cubes (~
anvils), six rectangular prisms (W anvils), and twelve
rectangular plates (compressible pads) are assembled together to form a cube. At the central part of this assembly,
a bipyramidal space is present for the material to be compressed. When the size of this cube-shaped assembly is
reduced by a couple of RH3 type guide blocks 2 or by a
cubic press, the volume of the pressure medium is reduced
in association with the reduction of thickness of the compressible pads, and also with sliding between two anvils in
contact.
The schematic illustration of the cross section of the
assembly is shown in Fig. 2, which helps the ex-planation
of the operational mechanism. When the assembly is
isotropically compressed, the pressure medium is uniaxially
compressed by an active advancement of a couple of N
anvils. The W anvils displace outward, giving rise to
the stroke of N anvils and also the laterally supporting
pressure on each anvil to reduce the stress in the anvils.
FIG. 1. Gcometry of MASS 3T8-90 mcchanism. Perspective view
showing Lhe anvil arran~el1lent (left), and external vicw of thl' assembly in culic' (ri!;ht). N- normal anvil; W-wed~e anvil; cp-compressihle pad (two pads arc comhined together forl1lin~ an L-shapcd
angle for comprehensive illustration).
Copyright
®
1975 by the American Institute of Physics
.
84
f
85
Kazuaki Masaki et al.: High pressure generation
85.
he
(01
{)
-
pressurizing state
pressurized state
FIG. 2. Operational mechanism of MASS 318-90 driven by means of a
cubic press. An imaginary cross section is shown for the sake of simplicity. N-normal anvil; \V-wedge anvil; cp~ompressible pad;
pm-pressure medium; hc- head of a cubic press. Arrows show the
displacement of the components.
The displacement and the lateral support of anvils are ..
controlled by the thickness change of the compressible pads.
Therefore, the effective compressibility of the pads should
be at the optimum value in order to attain better pressuregenerating efficiency without any failure of anvils. The
guiding criterion of determining the effective compressibility of the pads follows the "compressibility matching"
principle proposed in a previous paper.2 However, the trial
and error adjustment of the compressibility of the pads
should be made to reach an optimum compressibility,
because we do not always have sufficient quantitative data
on the deformation of anvils, compressible pads, and
pressure medium.
By assuming that the anvils are rigid, the relation between
the volume of the pressure medium and the stroke of the
anvils, or the change of overall size of the 3I8-90 assembly,
is given by
(a)
FIG. 4. (a) Geometry of
pressure megium with a
sample cell. The pressure
medium surrounded by two
N anvils and six \V anvils is
a combination of two pyramids at the starting state.
(b) ~ross section of the
pressure medium . A mica
sheet is inserted between
anvils in contact in order to
keep electric insulation and
also to reduce friction between anvils. (c) Cross section at the ultimate compression. This state never
takes place, but this figure
shows the situation in which
the volume of the pressure
medium does not reduce to
zero, leaving six small
pyramids S.
(b)
(1)
where -V is the volume of the pressure medium, L is the
overall size of an assembly, I is the size of an N anvil, and a
is the truncated edge length (TEL) of an N anvil. Equation
(1) is shown by a broken line, ABCD, in Fig. 3.
Tl>e overall size of the assembly, L, reduces from the
maximum values of 21 to 21- (V1/3)a, an ultimate limit due
::>
42.1
EO
42.5
"0
CII
E
43.0
/,;
::J
43.5
44.0
(mrrr"3)
.................._-.
~ 03
~
CII
L.
::J
III
III
CII
(mm)
8
6
"-
to contact of two N anvils. Even at the smallest limit of
L, V is not completely zero because of the six spaces [S of (c)
in Fig. 4J remaining among anvils. However, sufficient
volume reduction to generate very high pressure is reached
before the ultimate limit. Although the trace in Fig. 3 is not
applied accurately to the actual system because anvils are
not rigid bodies, the operational situation of the present type
apparatus is well described by it. The prescribed relation
of V to L in the present experiment for TEL=4 mm is shown
by a trace B -+ C in Fig. 3.
EXPERIMENTS
a.
'0
CII
E
3
.
,,
,
,,
o
>
l~ 03
912
o
4
/c
,,
,,
,,
2
o
~--------------------------~--~o
2l
2L-'ja
overall
size, L
FIG. 3. Relation of the volume reduction of the pressure medium to the
overall size of the assembly. l is a size of N anvil and a is TEL.
Rev. Sci. Instrum., Vol. 46, No.1, January 1975
The size of the pressure medium is an important factor
for the users of the high pressure instruments. Clearly
smaller volume is advantageous to generate high pressure .
On the other hand, larger volume is advantageous for
pressure generation combined with high temperature at
the expense of pressure. We specify the volume of the
pressure medium nominally by indicating the truncated
edge length (TEL) of N anvils. Although we made the test
experiments on five cases, TEL=3, 4, 6, to, and 12 mm, the
descriptions of experiments and their results are mostly
made on ~he case ·TEL=4 mm.
Kazuaki Masaki et al.: High pressure generation
86,
86
TAlllE 1. :\faterial and si7.e of lhe components used for the presen t
MASS 318-90 assembly driven by a cuhic press.
Component
N anvil
Wanvil
Compressible pad
Pressure medium
~[aterial
4
Size
cemented tun~sten carbide with 5% cobalt
for binder
hardened tool steel JIS
SKH-2, HRC=60
laminated plate made of
sheet of mica and paper
pyrophyllite, heat treated
at 700°C for 30 min
mica
Lubrication and
insulation sheet
Head of cubic
hardened die steel JIS
press
SKD-ll, HRC=45
.
22X22X22 mm'
TELa=4 mm
..
.?:
<J
22X19X19 mm'
2X22X(190r21) mm'
)
o
o
6. Electric resistance vs
applied force for ZnS.
FIG.
7.5 b mm', thickness
=l.63 b mm
thickness=O.l mm
Ll
o
a:
01
2
o
40X40 mm 2
-1
o
a TEL: truncated edge length.
Size at the starling state.
40
80
b
. .1
If
f
,
..
I
Table I shows the size and typical material of each component used in the present test runs of generating high
pressure. The compressibility of the pads is changed by the
thickness fraction of mica to paper. In order to keep the
electric insulation and to reduce the friction between anvils,
a sheet of mica of .....,0.1 mm thick (lubrication and insulation
sheet) is inserted between two anvils in contact.
When the size specifications in Table I are used, the
overall size of the assembled cube of MASS 318-90 is
43.3 X 43.3 X 43.3 mm 3 including the thickness of lubrication
and insulation sheets. In the present e:q>eriment, the
assembly was compressed by a cubic press9 with six hydraulic
rams at Government Industrial Research Institute, :-J"agoya.
A ~ressure calibrant with electric leads of Au foil 0.03 mm
thick is embedded in a pyrophyllite pressure medium. The
electric leads are connected to a couple of _ anvils and then
to anvil surfaces of the cubic press. The electric resistance
of the calibrant was measured by means of a two-probe
method, and re€Orded on the Y axis of an X - Y recorder.
The force applied to each face of the 318-90 assembly is read
by the oil pressure on the ram, and is recorded on the X
axis of the recorder.
RESULTS AND DISCUSSION
The pressure generated in a medium was calibrated by
means of the resistance change associated with the phase
transitions in the following calibrants lo . ll : Bi I-II = 26
4
3
!
.!
o
.
0
<J
UI
<J
.,.,
?:
o
FIG. 7. Electric resistance vs
applied force for GaP.
~
o
a:
01
o
160 200
kilobar; 'Bi III-V=77 kilobar; Pb I-II = 130 kilobar; ZnS
(semiconductor-metal) = 190 kilobar; GaAs (semiconductor-metal) = 190 kilobar; and GaP (semiconductor-metal)
=400 kilobar. The reported transition pressures of calibrants
above were those re-evaluated and adjusted to fit Drickamer's new scale. 12 The metallic transition in GaP was
recently studied by Onodera et at.,13 and was supposed to be
400 kilobar or a little higher on the basis of Drickamer's
new scale. In this paper we temporarily adopt 400 kilobar
for the transition pressure in GaP.
Figures 5, 6, and 7 show examples of large resistance
drops of several orders of magnitude, which are identified
with the transitions to the metallic phases mentioned above .
Two or three runs were made, usually on each calibrant,
and the calibration curve was constructed in Fig. 8 by
plotting the relationship between the transition pressure
and the applied force to each ram of the cubic press.
The other calibration points available are the second
resistance drop in GaAs at 230 kilobar,lO resistance maximum
in CdS at 330 kilobarll and resistance maximum in ZnS at
420 kilobar.1I
In order to detect the second resistance drop in GaAs,
additional compressions of GaAs were made very carefully
in a silver chloride cell to reduce the effect of shear stress.
However, the resistance drop takes place in too many steps
. to iden tilY the second one, as shown by a typical example
of Fig. 5.
4
FIG. 5. Electric resistance vs
applied force for GaAs. ·
120
Load ( t o ns )
2
~
.
~
0
tr
o
2'"
-I
0
~
\.
-I
o
40
80
120
160 200
Load (Ions)
Rev. Sci. Instrum., Vol. 46, No.1, January 1975
o
40
80
120
160
Load (Ians )
200
87
87
Kazuaki Masaki et al.: High pressure generation
I
o ZnS
v
400
(a)
.a 300
x:
...::J
.
~
III
III
.,
200
...
~
Cl..
e
100
40
80
120
Load
160
(b)
200 240
(tons)
FIG. 8. Relation between the generated pressure and the applied
force to each ram of a cubic press.
A reliable resistance maximum in CdS is not observed
clearly in the present experiments, although many runs were
tried with different materials, different cell geometries, and
also different ways of connecting the electric leads to the
calibrant. The electric resistance increased with the applied
force above 30 kilobar, and it certainly decreased after
passing through a ma:dmum, as indicated by Samara and
Drickamer,u However, the resistance maximum is observed
at a force lower than that expected from the pressure value
of 330 kilo bar and the calibration curve obtained by the
other calibration points. When the applied force is kept
constant, the resistance decreased with time at the pressure
around 300 kilobar. Therefore, the appearance of the
resistance maximum is probably due to the superposition
of this time-dependent nature of the resistivity. Since we
do not understand the present situation, the calibration
point of the resistance maximum in CdS is omitted from
Fig. 8.
The electric resistance maximum in ZnS was observed
in only one of three runs (TEL=4 nun), presumably
because the maximum is so small. Though the result was
not certain enough, this calibration point was also plotted
in Fig. 8 for comparison.
A smooth curve fitted to the data in Fig. 8 apparently
shows that pressures up to 500 kilobar are reached.
When the compressibility matching is well established,
no serious failure of anvils takes place. The W anvil sutTers
from small plastic deformation at the corner in contact with
the pressure medium. However, the extent of the deformation is usually so small that the same corner of an anvil is
Rev. Sci. Instrum., Vol. 46, No.1, January 1975
FIG. 9. Photograph showing typical failure of normal anvil.
used repeatedly, especially for runs below 200 kilobar.
Even after a run up to 500 kilobar, they are used two or
three times. Further, the \V anvil has eight corners tq be
used, and thus it is essentially used many times, unless
serious cracking takes place due to an inadequate operation.
The N anvils never show any visible failure below 200
kilobar. However, when the generated pressure exceeds 300
or 400 kilobar, and the anvils are repeatedly used , the central
part of the truncated face of the ~ anvil is plastically
dished by about 0.05 mm in some cases.
In some cases, cracks developed in J anvils, especially
after repeated and inadequate usage withou t good compressibility matching. Two different types of cracking are distinguished: (a) radial cracks running from the edge of the
truncated face to the opposite corner of an anvil, and (b)
tipoff cracks running superficially along the edges of the
truncated face and three major edges of I anvil (Fig. 9).
The failure of the first type apparently indicates the insufficiency of the lateral support on the anvil. The second
type of cracks may be developed during the decompression
process, due to the internal stress accumulated by the plastic
deformation of the anvil at the truncated face.
An apparent counterplan to prevent or to reduce t~ese
anvil failures is the increase of lateral support by making
the pad less compressible at the expense of pressuregenerating efficiency.
Calibration curves for ditTcrcnt values of TEL arc also
shown in Fig. 8. Since the -operalional conditions arc not
always the same for ditTerent TEL, the quantitative comparison is a little diflicult. However, there is stich a clear
-
.
..1
'88
•
- - - - - - - - - - -- - - -- - --y----.
88
Kazuaki Masaki et al.: High pressure generation
relation that the smaller volume makes it possible to attain
higher efficiency of pressure generation.
As will be inferred from Fig. 2, the MASS 318 is similar
to Drickamer's modification of the opposed anvil type
apparatus. The W anvils play almost the same roles as the
pyrophyllite gasket of the Drickamer's apparatus. lf However, the operational mechanism is quite different. If MASS
3I8 and Drickarner's.apparatus are compared, the advantage
of the MASS 318 over Drickamer's apparatus is apparent
in many respects. ' (1) The large volume, especially the
thicker pressure medium, is compressed by retaining action
of W anvils; (2) More lateral support and its control are
easily made on the active N anvils by means of the combined
role of the subordinate W anvils with enough rigidity and
of the compressible pads; (3) Shapes of the components '
are simple and making the supply of the components easy
both in cost and manufacturing; (4) A cubic press, which
has already been installed at many high pressure laboratories, is used to drive the apparatus. Further, there is no
gasket, and the scaling up of the MASS apparatus is
possible, and thus higher pressure in a larger volume may
be generated by means of larger force.
Through the technical experiences of the previous and
the present works, we are convinced that MASS 318-90
apparatus has arrived at the state of routine use for scientific
work at high pressure up to 500 kilobar in a volume in the
order of 10 mm3 • The present limitation on the pressure and
pressurized volume attainable is not a technical one but the
force safely available by the cubic press used in the present
work. It may be quite feasible to produce a high pressure
in the order of 1 Mbar in the near future by means of the
MASS 318-90 type apparatus.
Rev. ScI. Instrum., Vol. 46, No.1, January 1975
ACKNOWLEDG MENTS
Three (K. M., H . S., and M. K.) of the present authors
express their thanks to Drs. O. Fukunaga and T. Fujita of
Government Inorganic Material Institute for help in the
test runs at their institute. The authors would also like
to thank Prof. N. Kawai and Dr. A. Onodem of Osaka
University for their unpublished manuscript on the electric
transition in GaP.
The present work is supported financially by the Ministry
of Education (No. 842012), Japanese Geodynamic Committee and also by the Mitsubishi Foundation.
·Present address : Department of Civil Engineering, Aichi Institute of
Technology, Aichi, Japan.
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.
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