Effect of pressure on the phase transition behavior of ammonium nitrate
Ammonium nitrate (AN) is used as oxidizer in solid propellants, explosives, gas generator systems and also as a fertilizer. AN crystallizes in five polymorphic phases that appear at different temperatures. Phase transition of AN from one polymorphic phase to another is very important as an oxidizer...
Gespeichert in:
| Veröffentlicht in: | Физика и техника высоких давлений |
|---|---|
| Datum: | 2004 |
| Hauptverfasser: | , , |
| Format: | Artikel |
| Sprache: | Russisch |
| Veröffentlicht: |
Донецький фізико-технічний інститут ім. О.О. Галкіна НАН України
2004
|
| Online Zugang: | https://nasplib.isofts.kiev.ua/handle/123456789/168071 |
| Tags: |
Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
|
| Назва журналу: | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| Zitieren: | Effect of pressure on the phase transition behavior of ammonium nitrate / T.K. Mondal, N.C. Shivaprakash, K. Rajanna // Физика и техника высоких давлений. — 2004. — Т. 14, № 2. — С. 86-89. — Бібліогр.: 10 назв. — англ. |
Institution
Digital Library of Periodicals of National Academy of Sciences of Ukraine| _version_ | 1859716151477534720 |
|---|---|
| author | Mondal, T.K. Shivaprakash, N.C. Rajanna, K. |
| author_facet | Mondal, T.K. Shivaprakash, N.C. Rajanna, K. |
| citation_txt | Effect of pressure on the phase transition behavior of ammonium nitrate / T.K. Mondal, N.C. Shivaprakash, K. Rajanna // Физика и техника высоких давлений. — 2004. — Т. 14, № 2. — С. 86-89. — Бібліогр.: 10 назв. — англ. |
| collection | DSpace DC |
| container_title | Физика и техника высоких давлений |
| description | Ammonium nitrate (AN) is used as oxidizer in solid propellants, explosives, gas generator systems and also as a fertilizer. AN crystallizes in five polymorphic phases that appear at different temperatures. Phase transition of AN from one polymorphic phase to another is very important as an oxidizer and also as fertilizer. During its use as an oxidizer, whether pressure plays any role in phase transition is described in this paper. High Pressure−Differential Thermal Analysis (HP−DTA) system is used for this study.
|
| first_indexed | 2025-12-01T08:11:54Z |
| format | Article |
| fulltext |
Физика и техника высоких давлений 2004, том 14, № 2
86
PACS: 61.66.–f, 62.50+P, 81.30.–t
T.K. Mondal, N.C. Shivaprakash, K. Rajanna
EFFECT OF PRESSURE ON THE PHASE TRANSITION BEHAVIOR
OF AMMONIUM NITRATE
Department of Instrumentation, Indian Institute of Science
Bangalore − 560012, India
Received October 14, 2002
Ammonium nitrate (AN) is used as oxidizer in solid propellants, explosives, gas generator
systems and also as a fertilizer. AN crystallizes in five polymorphic phases that appear at
different temperatures. Phase transition of AN from one polymorphic phase to another is
very important as an oxidizer and also as fertilizer. During its use as an oxidizer, whether
pressure plays any role in phase transition is described in this paper. High Pres-
sure−Differential Thermal Analysis (HP−DTA) system is used for this study.
Introduction
AN is used as oxidizer in solid propellants, explosives and gas generator sys-
tems. Drawbacks of AN as a rocket fuel are low performance, low burning rates
and phase transition that influence the material properties. These drawbacks and
the development of the ammonium perchlorate-filled composites decreased the
interest in AN for application in solid propellants in sixties and seventies [1]. New
interest in AN was born when smokeless low-sensitive and ecologically harmless
propellants were required, stimulating further research for understanding the
phase behavior. Another primary application of AN is fertilizer. In the ortho-
rhombic IV stage, ammonium nitrate is effective as a fertilizer, but when the
compound changes phase, it is no longer viable as a fertilizing substance [2].
Ammonium nitrate crystals undergo various structural changes as the temperature
increases. AN crystallizes in five polymorphic phases that appear at different tem-
peratures [3−7]. Phase transition of AN from one polymorphic phase to another is
very important as an oxidizer even at higher pressure. During its use as an oxi-
dizer, whether pressure plays any role in phase transition is described in this paper.
Method
HP-DTA system is used for this study. This is a technique by which the ther-
mally induced transformations in materials, in other words any thermal effect in
the sample e.g. as a result of a phase transition or a chemical reaction, produced a
Физика и техника высоких давлений 2004, том 14, № 2
87
characteristic signal whose dependence on time just represents the measuring
curve of this method [8]. Pressure is generated by a hydraulic system. The applied
oil pressure is read by a thin-film pressure transducer with a high stability and
having operating range 0−4 GPa absolute. A piston cylinder is used for sample
holder [9]. Inside the cylinder pyrophyllite is used for sample and reference mate-
rial holders. Chromel-alumel thermocouples are used to measure temperature and
the temperature difference. To compensate for the heat losses from the cell a
guard heater is introduced outside the piston cylinder. The temperature is main-
tained at the theoretical value computed from the heat transfer equations for the
piston cylinder block. A pulse width modulation circuit is introduced to maintain
the zero value between the experimental and set value. An ON/OFF control is in-
troduced for the guard heater. With the help of heat transfer equations the theo-
retical value of temperature close to the guard heater is calculated and is consid-
ered as set temperature for it. The ON/OFF control circuit tries to bring down the
difference between the experimental and the set value to zero. The pressure con-
trol is achieved by using a valve assembly. Temperature is calibrated with the
thermocouple output. The conversion of the sample thermocouple output to the
corresponding temperature and comparison with set temperature are done by the
software. The determination of the heat of transition or the mass of the reactive
sample from the area of the curve peak is a widely used procedure in DTA [8]
which can be written simply as
∆Hmc = kA∆Ts ,
where ∆H is the heat of transition in J/kg, m is the mass of reactive sample in kg, c
is the chart speed in m/s, k is the calibration coefficient and A is the curve peak
area in m2, ∆Ts is the differential temperature sensitivity in K/m. The calibration
coefficient is related to the geometry and thermal conductivity of the sample
holder and is usually determined by calibration of the system with compounds
having known heats of transition. To check the system sensitivity, the both cavi-
ties are filled with alumina powder and heated. Benzoic acid is used to show the
repeatability of calibration coefficient and temperature calibration. The pressure is
calibrated by the phase transition of bismuth, ytterbium and benzoic acid.
Results and discussion
During the use of AN as an oxidizer, the temperature automatically raises be-
cause of burning the fuel. In the present study, three phase transitions of AN and
the melting of the same are observed.
On heating from room temperature, humid ammonium nitrate transformed
from phase IV into phase III (315 K), then phase III into phase II (355 K) and
phase II−I (401 K) [8]. The DTA curves for this are shown in Fig. 1. The standard
DTA curve reported in literature [8] is also shown in the same figure. The DTA
curves obtained in our experiment under higher pressure are shown in Fig. 2.
When pressure is applied both the phase transition IV to III and III to II correspond-
ing to 315 K and 355 K shift to higher temperatures. The transition from phase IV
Физика и техника высоких давлений 2004, том 14, № 2
88
Fig. 1. The DTA curves of humid AN (- - - – literature, ___ – experimental)
Fig. 2. Plot of temperature vs differential temperature of AN under pressure
(orthorhombic, space group ‘pmmn’) to phase III (orthorhombic, space group
‘pnma’). In the phase III to phase II transition, orthorhombic phase goes to
tetragonal phase.
The shifting of the both peaks to higher temperature can be explained as fol-
lows. According to a model of Amoros [10] for phase IV the planar nitrate groups
oscillate around an axis in direction of c. Three axes a, b and c are the lattice pa-
rameters correspondingly in the x, y and z direction. The nitrate groups lie linearly
in the ‘a’ direction at ambient temperature (Fig. 3). Stronger oscillations with in-
creasing temperature cause the strong expansion of ‘b’. As the nitrate groups de-
viate more and more from the linear position in direction of ‘a’, this parameter
shrinks slightly. With an increasing parameter ‘b’ and a decreasing ‘a’, the basis
of elementary cell approaches tetragonality, which is reached with the transition
IV/II twisting the nitrate groups into the 45° position. But as pressure increases
the nitrate group comes closer, the oscillatory path reduces as the repulsion starts.
This can be seen as peaks shifts towards higher temperature so that the pressure
effect is nullified by adding more heat.
Fig. 3. Oscillation and twist of the nitrate groups on heating
Физика и техника высоких давлений 2004, том 14, № 2
89
Conclusion
Both temperature and pressure have effects on the phase transition of AN. This
has been observed in the high pressure-differential thermal analysis system.
1. M.J. Herrmann, W. Engel, Propellants Explosives Pyrotechnics 22, 143 (1997).
2. S. Yamamoto, Y. Shinnaka, J. Phys. Soc. Japan 37, 724 (1974).
3. B.W. Lucas, M. Ahtee, A. Hewat, Acta Cryst. B35, 1038 (1979).
4. B.W. Lucas, M. Ahtee, A. Hewat, Acta Cryst. B36, 2005 (1980).
5. C.S. Choi, J.E. Mapes, E. Prince, Acta Cryst. B28, 1357 (1972).
6. M. Ahtee, K.L. Smolander, H.W. Lucas, A.W. Hewat, Acta Cryst. C39, 651 (1983).
7. C.S. Choi, H.J. Prask, Acta Cryst. B39, 414 (1983).
8. W.M. Wesley, Thermal analysis, John Willey & Sons, New York (1974).
9. P.W. Bridgman, Phys. Rev. 60, 351 (1941).
10. J.L. Amoros, P. Alonso, M. Canut, Bol. Real Soc. Esp. Hist. Nat. G56, 77 (1958).
|
| id | nasplib_isofts_kiev_ua-123456789-168071 |
| institution | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| issn | 0868-5924 |
| language | Russian |
| last_indexed | 2025-12-01T08:11:54Z |
| publishDate | 2004 |
| publisher | Донецький фізико-технічний інститут ім. О.О. Галкіна НАН України |
| record_format | dspace |
| spelling | Mondal, T.K. Shivaprakash, N.C. Rajanna, K. 2020-04-20T18:45:36Z 2020-04-20T18:45:36Z 2004 Effect of pressure on the phase transition behavior of ammonium nitrate / T.K. Mondal, N.C. Shivaprakash, K. Rajanna // Физика и техника высоких давлений. — 2004. — Т. 14, № 2. — С. 86-89. — Бібліогр.: 10 назв. — англ. 0868-5924 PACS: 61.66.–f, 62.50+P, 81.30.–t https://nasplib.isofts.kiev.ua/handle/123456789/168071 Ammonium nitrate (AN) is used as oxidizer in solid propellants, explosives, gas generator systems and also as a fertilizer. AN crystallizes in five polymorphic phases that appear at different temperatures. Phase transition of AN from one polymorphic phase to another is very important as an oxidizer and also as fertilizer. During its use as an oxidizer, whether pressure plays any role in phase transition is described in this paper. High Pressure−Differential Thermal Analysis (HP−DTA) system is used for this study. ru Донецький фізико-технічний інститут ім. О.О. Галкіна НАН України Физика и техника высоких давлений Effect of pressure on the phase transition behavior of ammonium nitrate Article published earlier |
| spellingShingle | Effect of pressure on the phase transition behavior of ammonium nitrate Mondal, T.K. Shivaprakash, N.C. Rajanna, K. |
| title | Effect of pressure on the phase transition behavior of ammonium nitrate |
| title_full | Effect of pressure on the phase transition behavior of ammonium nitrate |
| title_fullStr | Effect of pressure on the phase transition behavior of ammonium nitrate |
| title_full_unstemmed | Effect of pressure on the phase transition behavior of ammonium nitrate |
| title_short | Effect of pressure on the phase transition behavior of ammonium nitrate |
| title_sort | effect of pressure on the phase transition behavior of ammonium nitrate |
| url | https://nasplib.isofts.kiev.ua/handle/123456789/168071 |
| work_keys_str_mv | AT mondaltk effectofpressureonthephasetransitionbehaviorofammoniumnitrate AT shivaprakashnc effectofpressureonthephasetransitionbehaviorofammoniumnitrate AT rajannak effectofpressureonthephasetransitionbehaviorofammoniumnitrate |