Ammonium perchlorate, thermal

Fig 25 The Effects of Gamma-Ray 235U Fission Spectrum Neutron, and Combined Gamma-Ray and Neutron Irradiation on Whole Crystals of Ammonium Perchlorate Thermally Decomposed at 227° (Ref 224)... 

Because of the use of ammonium perchlorate as a soHd oxidizer for rocket propeUants, the thermal decomposition has been much studied (29—32). Three separate activation energies have been observed for AP decompositions an activation energy of 123.8 kJ/mol (29.6 kcal/mol) is found below 240°C of 79.1 kj/mol (18.9 kcal/mol) above 240°C and finally, of 307.1 kj/mol (73.4 kcal/mol) between 400—440°C (33,34). Below 300°C, the equation... 

The ammonium perchlorate solution is spray-dried to the desired crystal size at air temperatures below 150°C and crystal temperatures of about 110°C. This procedure provides a pure product having a controlled grain size. Prior mechanical and thermal treatment affects the isothermal... 

The Thermal Decomposition of Ammonium Perchlorate — A Literature Review , U of Miami. Dept of Chem Special Report 6 (1968), AD 673542 43) O, Svejka, CzechP 129074... 

Although the thermal-ignition theory was developed for double-base propellants, several investigators have attempted to correlate the ignition characteristics of composite propellants using this approach. Baer and Ryan (Bl) have correlated ignition data for a polysulfide-ammonium perchlorate... 

A considerable amount of research has been conducted on the decomposition and deflagration of ammonium perchlorate with and without additives. The normal thermal decomposition of pure ammonium perchlorate involves, simultaneously, an endothermic dissociative sublimation of the mosaic crystals to gaseous perchloric acid and ammonia and an exothermic solid-phase decomposition of the intermosaic material. Although not much is presently known about the nature of the solid-phase reactions, investigations at subatmospheric and atmospheric pressures have provided some information on possible mechanisms. When ammonium perchlorate is heated, there are three competing reactions which can be defined (1) the low-temperature reaction, (2) the high-temperature reaction, and (3) sublimation (B9). 

The thermal reactions of ammonium perchlorate (AP) are unusually complicated. On account of the importance of this compound as a solid propellant and also its intrinsic interest, an intensive and widespread series of studies has been completed using various experimental approaches. The main kinetic characteristics of the reactions involved and the mechanistic explanations of these observations are largely agreed. There have been two detailed reviews of the literature to mid-1968 [59,357]. 

Fig. 17. Unified reaction scheme for the thermal decomposition of ammonium perchlorate, proposed by Jacobs et al. [59,925,926], In the low temperature reaction, the interaction occurs between adsorbed species (a) whereas the high temperature reaction and sublimation process involved volatilization intermediates (g). X] and X2 represent mixtures of intermediates.

Materials for a batch of ammonium perchlorate castable propellant were charged into a mechanical mixer. A metal spatula was left in accidentally, and the contents ignited when the mixer was started, owing to local friction caused by the spatula. A tool-listing safety procedure was instituted [1]. The literature on the kinetics of thermal decomposition has been reviewed critically [2],... 

The polymeric hydrocarbon also acts as a binder of the particles, holding them together so as to formulate a propellant grain. Ammonium perchlorate (AP) is a typical crystalline oxidizer and hydroxy-terminated polybutadiene (HTPB) is a typical polymeric fuel. When AP and HTPB are decomposed thermally on the propellant surface, oxidizer and fuel gases are produced, which diffuse into each other and react to produce high-temperature combustion gases. 

P.W.M. Jacobs 8c A. Russell-Jones, "The Thermal Decomposition and Ignition of Ammonium Perchlorate + Copper Chromite , Ibid, pp 457-62 16) P.A. Urtieu 8c A.K. 

Another type of testing, that of electrostatic sensitivity, has been demonstrated in some cases to be more properly a delicate test of the ignitability of the material under localized thermal stress which correlates best to the friction sensitivity of the system under test rather than to electrostatic hazards. On the other hand, electrostatic tests done in the supposed atmosphere above a propellant mixer were reduced in absolute value by more than an order of magnitude when the ammonium perchlorate dust actually present was introduced in the test since this altered the potential path for spark discharge within the system. 

The most important attributes of this invention are high impulse performance coupled with high exit temperature on primary combustion and favorable boron species in the primary motor exhaust. The system is also insensitive to impact and possesses excellent thermal stability at elevated temperatures. Additionally, the system is readily castable since the addition of solid oxidizers is not required. Further, high flexibility in the ballistic properties of the gas generator can be achieved by the addition of solid oxidizers such as ammonium nitrate, ammonium perchlorate, hydroxylammonium perchlorate, potassium perchlorate, lithium perchlorate, calcium nitrate, barium perchlorate, RDX, HMX etc. The oxidizers are preferably powdered to a particle size of about 10 to 350 microns [13]. 

Another constituent of perchlorate explosives, ammonium perchlorate, unlike ammonium chlorate, is stable. It is also dissimilar to potassium perchlorate in being an explosive in the pure state, like ammonium nitrate. The greater specific gravity of ammonium perchlorate gives to explosives with which it is mixed a greater power than that of similar ammonium nitrate explosives. The former are also more sensitive than chlorate explosives to friction and impact and to thermal ignition. 

The recent experiments by Galwey and Jacobs [7a] were mainly dedicated to examining the thermal decomposition of ammonium perchlorate above ca. 350°C. They found the decomposition differs in several respects from that below this temperature, complete decomposition occurs, whereas at low temperatures a residue of ammonium perchlorate always remains as described above. 

Recently Freeman, Anderson and Campisi [11] examined the effects of X-rays on the chemical reactivity of ammonium perchlorate in the solid state. They found that pre-exposure of ammonium perchlorate to high energy radiation greatly affects the way it decomposes thermally. 

An electron spin resonance study by Hyde and Freeman [12] revealed that ammonia radical ion NH form when ammonium perchlorate is exposed to X-rays. This radical ion was found to be stable in the ammonium perchlorate lattice up to 120°C. It is not formed during thermal decomposition and is not present in ammonium perchlorate sublimate. 

The introduction of silver ions which act as electron traps enhances the radiation-induced changes in the thermal decomposition of ammonium perchlorate. Irradiated samples containing silver show thermal decomposition similar to samples without silver, but which received a considerably greater radiation dose. 

The same authors [7b] examined the thermal decomposition of ammonium perchlorate with charcoal (see also Vol. III). At temperatures below 240°C the... 

Oxygen Taliani Test of Gamma-Irradiated Propellants ARP, AHH, and CDT , NPP-TMR-172, Naval Propint Plant, Indian Head (1959) 78) E.S. Freeman et al, The Effects of X-Ray and Gamma Ray Irradiation on the Thermal Decomposition of Ammonium Perchlorate in the Solid State , JPhysChem 64, 1727 (1960) also PATR 2673 (1960) 79) G. Todd E. Parry,... 

P.W. Levy, "Thermal Decomposition of Irradiated Orthorhombic Ammonium Perchlorate , Nature, 1287 (1966) 164) T.C. Castorina et... 

Levy P.J. Herley, Effects of Radiation on the Thermal Decomposition Induction Period in Ammonium Perchlorate and other Pseudostable Materials , JChemPhys 75, 191 (1971) 209) V.V. Boldyrev, Radiolysis of Crystalline... 

Herley et al, Effect of Fast Neutron, Gamma-ray and Combined Radiations on the Thermal Decomposition of Ammonium Perchlorate Single Crystals , JChemPhys 60, 2340 (1974)... 

Herley et al, Recent Radiation Effect Studies on Ammonium Perchlorate. Part II The Effect of Fast Neutron, Gamma Ray and Combined Radiation on the Thermal Decompositions of- Ammonium Perchlorate Powder—Aluminum Particle Mixtures , Ibid, paper 2.2b, pp 301—15 (1975) 242) W.D. Hutchinson, Neutron Effects on Solid Propellants , Ibid, paper 2.6, pp 281-99 (1975) 243) R.A. Benham F.H. Mathews,... 

Thermal Decomposition of Ammonium Perchlorate During Gamma-Ray Irradiation , Defense Nuclear Agency Rept DNA 4032P-3,... 

Insights on the Thermal Decomposition of Ammonium Perchlorate from Studies on Very Large Single Crystals , Proc 8th Intern Symp on Reactivity of Solids, Gottenberg, Sweden (1976)... 

Al Fakir, M. S., Progr. Astronaut. Aeronaut., 1981, 76, 5512—564 Admixture of lithium perchlorate [1] or zinc perchlorate [2] leads to decomposition with explosion at 290° or ignition at 240°C, respectively. The role of ammine derivatives of lithium and magnesium perchlorates in catalysing the thermal decomposition of ammonium perchlorate has been studied [3], and lithium perchlorate has a strong catalytic effect on the burning rate [4]. 

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