Role of point defects in the thermal decomposition of ammonium perchlorate

1968 ◽  
Vol 307 (1490) ◽  
pp. 303-315 ◽  
Keyword(s):  
Electrical Conductivity ◽  
Thermal Decomposition ◽  
Single Crystals ◽  
Ammonium Perchlorate ◽  
Point Defects ◽  
Defect Structure ◽  
Electrical Conductance ◽  
Charge Carriers ◽  
Point Defect Structure

The thermal decomposition of ammonium perchlorate has usually been described in terms of chemical reactions with the point defect structure of the solid ignored. Both the isothermal and adiabatic decompositions have been reinvestigated over the temperature range 200 to 450°C. There is a good correlation between the isothermal d. c. electrical conductance of single crystals, and of conductance as a function of temperature with the extent of decomposition, indicating that charge carriers play a significant role in the thermal decomposition. The study of the electrical conductivity as a function of temperature has resulted in the assignment of a probable defect structure to ammonium perchlorate: cationic Frenkel type below 250°C and Schottky disorder at higher temperatures. This suggests an explanation for the phenomenon of only 30% decomposition below 250°C and 100% above this temperature.

Role of silver compounds in promoting the thermal decomposition of ammonium perchlorate

1986 ◽  
Vol 1 (3) ◽  
pp. 235-251 ◽  
Author(s):  
Andrew K. Galwey ◽  
Mohamed A. Mohamed ◽  
David S. Cromie
Keyword(s):  
Thermal Decomposition ◽  
Ammonium Perchlorate ◽  
Silver Compounds

The low temperature thermal decomposition of ammonium perchlorate: nitryl perchlorate as the reaction intermediate

1984 ◽  
Vol 396 (1811) ◽  
pp. 425-440 ◽  
Keyword(s):  
Thermal Decomposition ◽  
Low Temperature ◽  
Ammonium Perchlorate ◽  
Bond Formation ◽  
Covalent Bond ◽  
Subsequent Reaction ◽  
Temperature Decomposition ◽  
Covalent Bond Formation ◽  
Localized Reaction

We identify nitryl perchlorate as the essential intermediate in the low temperature thermal decomposition of ammonium perchlorate AP. Evidence supporting this identification includes the analytical detection of an oxidized nitrogenous species in partly reacted AP and the ability of ammonium nitrate and several other nitrates to markedly reduce the induction period to decomposition of AP and to accelerate the subsequent reaction. It is also shown that the measured rate of the reaction of pure AP is in very satisfactory agreement with that estimated to result from this amount of NO 2 ClO 4 present. This mechanism differs from those currently accepted, in which the controlling process is believed to involve the transfer of either a proton or an electron. Our proposal is based on the known instability of NO 2 ClO 4 at reaction temperature ( ca . 500 K), the enhanced reactivity compared to the ionic alkali perchlorates being ascribed to covalent bond formation O 2 NO─ClO 3 . Subsequent reactions of the products of breakdown of this species, NO + , ClO 3 - and 2O or O 2 , are regarded as capable of oxidizing reactant NH 4 + (→NO 2 + ), thus regenerating the intermediate. Localized reaction in migrating ‘particles’ of fluid NO 2 ClO 4 , advancing through the reactant and leaving a residue of porous NH 4 ClO 4 , explains the unusual, incomplete low temperature decomposition that is characteristic of AP. The article reports comparative kinetic data for the decomposition of pure AP and the reaction initiated by various added nitrates. Rate studies are complemented by scanning electron microscope examinations of the geometry of interface development and the structure of the decomposed salt. From these and analytical results the role of nitryl perchlorate in AP decomposition is discussed.

Point Defects and Protonic Conduction in A3B'B”2O9 Compounds

1994 ◽  
Vol 369 ◽  
Author(s):  
Yang Du ◽  
A.S. Nowick
Keyword(s):  
Electrical Conductivity ◽  
Ir Spectra ◽  
Point Defects ◽  
Defect Structure ◽  
Complex Perovskite ◽  
Divalent Ions ◽  
Protonic Conduction ◽  
Protonic Conductors ◽  
Lower Activation ◽  
Perovskite Type

AbstractWe have investigated the defect structure and protonic transport properties of nonstoichiometric complex perovskite-type compounds of the type A3B'1+xNb2-xO9-δ. where A and B' are both divalent ions. Protons are incorporated by treatment in H2O vapor and their presence is manifested by the appearance of an OH band in the IR spectra, as well as by the large increase in electrical conductivity to produce excellent protonic conductors, with lower activation energies. A non-classical isotope effect, in which the Arrhenius plots for D+ and H+ cross over, can be explained by a modification of the classical ART hopping theory.

Anomalous Strain Rate Sensitivity of Flow Stress in Ni3Ge Single Crystals. The role of Point Defects

2017 ◽  
Vol 60 (3) ◽  
pp. 494-501
Author(s):  
Yu. V. Solov’eva ◽  
V. A. Starenchenko ◽  
O. D. Pantyukhova ◽  
S. V. Starenchenko ◽  
A. N. Solov’ev ◽  
...  
Keyword(s):  
Flow Stress ◽  
Strain Rate ◽  
Single Crystals ◽  
Strain Rate Sensitivity ◽  
Point Defects ◽  
Rate Sensitivity

Die elektrische Leitfähigkeit hydratisierter Sulfate zwei- und dreiwertiger Kationen.

1976 ◽  
Vol 31 (10) ◽  
pp. 1313-1316
Author(s):  
Heinz P. Fritz ◽  
Dagmar Laschka
Keyword(s):  
Electrical Conductivity ◽  
Hydrogen Bonds ◽  
Proton Conductivity ◽  
Activation Energies ◽  
Charge Carriers ◽  
Elektrische Leitfähigkeit

The electrical conductivity of polycrystalline pellets of ZnSO4 · 7 H2O, MgSO4 · 7 H2O, CuSO4 · 5 H2O, KAl(SO4)2 · 12 H2O, NH4Al(SO4)2 · 12 H2O and KCr(SO4)2 · 12 H2O was measured. By coulometry the role of protons as charge carriers was determined. A correlation is given between the strength of hydrogen bonds and the activation energies for the proton conductivity.

Ruthenium Doped Gadolinium Titanate: Effects of a Variable Valent Acceptor on Ionic and Electronic Conduction

1992 ◽  
Vol 293 ◽  
Author(s):  
M.A. Spears ◽  
H.L. Tuller
Keyword(s):  
Electrical Conductivity ◽  
Thermoelectric Power ◽  
Defect Structure ◽  
Oxygen Vacancies ◽  
Ionic Conduction ◽  
Electronic Conductivity ◽  
Electronic Conduction ◽  
Defect Band ◽  
Electron Migration

AbstractWe have investigated ruthenium doped gadolinium titanate, Gd2(RuxTi1-x)2O7-δ with 0 ≤ x ≤ 0.2, to determine the role of variable valent Ru in influencing the defect structure and transport properties of the pyrochlore host. We have developed a defect chemical model to interpret electrical conductivity, thermoelectric power, and thermogravimetry data. We have found that Ru acts as an acceptor compensated in large part by oxygen vacancies, resulting in enhanced ionic conduction at low values of x. For larger values (x ≈ 0.05), electronic conductivity predominates which we attribute to electron migration by hopping through a Ru-derived defect band.

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