Transcript SHOCK-ASSISTED SOLID SOLID SYNTHESIS: STRUCTURE OF

SHOCK-ASSISTED SOLIDSOLID SYNTHESIS:
STRUCTURE OF REACTION ZONE
S. V. Buravova, Yu. A. Gordopolov, N. A. Denisova,
and I. V. Saikov
Institute of Structural Macrokinetics and Materials Science, Russian
Academy of Sciences, Chernogolovka, Moscow, 142432 Russia
e-mail: [email protected]
1. M.F.Gogulja, I.M.Voskoboynikov, A.J.Dolgoborodov, et al.
Interaction of sulfur and aluminum behind shock waves. Chemical
Physics, 1992,v. 11, №2, (A method of optical pyrometry)
Al/S
Profile of pressure
in the indicator
liquid ССl, for
samples 55 Аl/S
(1 and 2); sulfurs
(3); aluminum (4)
Dependence of brightness
temperatures in time. Р~34.6
(18.2) GPа.
At the beginning stages of measurements, the temperature
decreases. And in samples with large particles of aluminum the
temperature rise is observed.
2. M.F.Gogulja, M.A.Brazhnikov, About characteristic times of chemical
reactions in heterogeneous systems at dynamic loading, Chemical Physics, 1994, v. 13,
11, 88-101
Change of intensity of radiation
(=740 nanometers) the pressed
powder of sulfur on contact border
with LiF (1) and glycerin (2)
Change of intensity of radiation (=740
nanometers) pressed powder Al on contact
border with LiF, 1-large, 2 – fine.
At the first moments of record, high level of radiation shows
hot spots during shock loading solid – solid heterogeneous
system.
3. SULFIDES. S.S.Batsanov, M.A.Brazhnikov, G.V.Simakov, I.I.Maxim. Physics of
burning and explosion, 1994.
M.F.Gogulja, I.M.Voskoboynikov, A.J.Dolgoborodov, N.S.Dorokhov,
M.A.Brazhnikov, Chemical physics, 1991, v. 10, 3, p. 420 ; т 30, №3, pp. 107-112.
Degree of transformation
Μg/S (43/57) - 0.2 at pressure 24 GPа
Al/S (55/45) - 0.5 at pressure 27 GPа.
Effective brightness temperatures
Μg/S(24 GPа)- 28000 Al/S (27) -3000К, Ti/S (28 GPа) - 2250К
Sn/S 1480 - 3320 (at pressure 32.4 - 57.5 GPа)
Time of chemical reaction is comparable with resolving time of a
pyrometer (20 - 50 nanoseconds).
4. Silicides. N.N. Thadhani, R.A. Graham, T. Royal, E. Dundar, M.U.
Anderson and G.T. Holman, Shock-induced chemical reaction in titaniumsilicon powder mixtures of different morphologies: Time-resolved pressure
measurements and materials analysis., Appl. Phys. 1997, v. 82, N 3, p.11131128
System Ti+Si. Reaction occurs only in mixtures
containing particles of the average size (at pressure 1.5
GPа). Mixtures with large and fine particles
Systems Mo+Si and Nb+Si. Reactions are not initiated
at pressures up to 7 GPа.
.
5. Ni+AL D.E.Eakins, N.N. Thadhani. Discrete particle simulation of shock
wave propagation in a binary Ni+Al powder mixture, J. Appl. Phys., v. 101,
043508 1 - 043508 11 (2007)
A synthesis takes place at 8-10 GPА,
it exceeds yield strength. Under the
conditions a shock wave is split into
an elastic precursor and plastic wave
Shock wave propagation
In mixtures with 80 % and 60 % density, the high
pressure zone moves after the precursor
following to wide area low amplitude pressure to
networks of elastic harbingers. The distance
between them is 300 micron for 80 % density,
100 microns for 60 %, and completely absent for
45 % density.
•6. S.S. Batsanov, Features of the solid - solid transformations initiated by shock
waves, Successes of Chemistry, 2006, v. 75, (7), pp. 669
•N.N. Thadhani, R.A. Graham, T. Royal, E. Dundar, M.U. Anderson and G.T.
Holman, Shock-induced chemical reaction in titanium-silicon powder mixtures of
different morphologies: Time-resolved pressure measurements and materials analysis,
Appl. Phys. 1997, v. 82, N 3, p.1113-1128
Sn+S
Nb+Si
Sn+Te
Cu + Al
15 GPа
20 GPа
45 GPа
32 GPа
S+Al
Ti+Ni
Ti+C
Fe+S
15 GPа
3.2 GPа
15 GPа
28 GPа
Ni+Al
Al+Fe2O3
Ti+Si
It was experimentally proved that
(1)Superfast chemical reaction takes place;
(2) reaction is initiated in local the “hot spots”;
(3) degree of transformation is insignificant
(4) shock wave is split into an elastic precursor and plastic wave
5.4-15 GPа
5 GPа
1.5 GPa
7. Low – velocity wave regime of explosive transformation.
A.F.Beljaev, V.K.Bobolev, A.I.Korotkov, A.A.Sulimov, S.V.Chujko.
Burning transition of the condensed systems in explosion. 1973
Both shock wave and reaction zone
(low -velocity detonation) propagate
stationary up to 40 - 50 diameters of
a charge
Figure I illustrates transition of low –
velocity detonation into a high-speed
one depending on the charge diameter
(tetryl = 0.92)
Figure II illustrates dependence of a low –
velocity detonation on density (ten, plexiglass
capsule)
of mass velocity for the case low – velocity detonation
in high density charge
8. Profile
The basic role of a metallic capsule is
pressure maintenance at the certain level.
Low-velocity regime of explosive transformation with subsonic
speed is caused by movement of the plastic wave without jump at
the front.
The plastic wave in trotyl extends with subsonic speed.
Mechanical activated mixture of Al + teflon has the same profile of mass
velocity
9.Wide zone of reaction is the basic feature of low-velocity
detonation.
The distance between fronts is 40 mm at 1400
km/s and does not vary in time.
For a charge with high density the distance
between fronts is 5 - 10 mm at 1000 km/s
Chemical reaction arises behind a compression wave with a significant delay.
The heat release is 30 - 35 % of normal detonation energy
10. Area of low-velocity detonations propagation is 7-15 kbars.
This is an area where the shock wave is split on elastic and
plastic waves.
Oscillogram of mass velocity in the pressed trotyl.
a - shock wave (10 kbar); b - elastic and plastic wave
(р=5 kbar)
11. Similarity and distinction of reactions during synthesis
and decomposition.
(1) Reaction occurs in hot spots
(2) Not full degree of transformation during
synthesis and heat release at decomposition
(3) Shock wave slits on elastic and plastic ones
Main distinctions
Ultrafast reaction (nanoseconds) during synthesis
and
the slow development of the reaction during low –
velocity detonation (up to dozens micro seconds)
12.
Conclusion
It is necessary to study structure of a full reaction
zone including afterburning one during solid –
solid synthesis
The aim of the work is to attract attention to the problem
13. Gogulja M.F., Бражников. М.А. About characteristic times of
chemical reaction in heterogeneous systems at dynamic loading.
Chemical physics, 1994, т. 13, N 11, 88 - 101
Mg/S
Unique work .
Time measurement made 6
microns.
After sharp decrease of
temperature growth of
temperature that testifies to
afterburning process takes
place.
Change brightness temperatures of the sample on border of section, 1-3
stoichiometry 43/57; 4-5 - 63/37; 1,4 (LiF); 2 - (H2 O); 3, 5 - ПММА;
the shaped line is received on =720 nanometers; continuous - on =420
nanometers.