scholarly journals Thermal Decomposition of Tricresyl Phosphate on Ferrous Surfaces

2021 ◽  
Vol 125 (9) ◽  
pp. 5076-5087
Author(s):  
Arash Khajeh ◽  
Fakhrul Hasan Bhuiyan ◽  
Jon-Erik Mogonye ◽  
Rose A. Pesce-Rodriguez ◽  
Stephen Berkebile ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Tricresyl Phosphate

scholarly journals The sensitiveness of explosives - Build-up of detonation of lead azide in various media

1948 ◽  
Vol 241 (831) ◽  
pp. 238-248
Keyword(s):  
Thermal Decomposition ◽  
Mass Flow ◽  
Diethylene Glycol ◽  
Dibutyl Phthalate ◽  
Testing Temperature ◽  
Lead Azide ◽  
Tricresyl Phosphate ◽  
Self Heating ◽  
Boiling Points ◽  
The Masses

Two mechanisms have been proposed for the build-up of detonation by solid explosives: ( a ) In the self-heating mechanism, when heat is evolved during thermal decomposition of the explosive faster than it can be conducted away, the temperature of the mass and the consequent rate of decomposition rise more and more. Ultimately the whole mass deflagrates more or less violently. The mathematical condition for self-heating has been formulated, but experiments show that a further condition is required for transition from deflagration to detonation, which has not yet been formulated mathematically. ( b ) In the mass-flow mechanism, when the gas evolved during chemical decomposition of the explosive becomes comparable with the molecular mass flow required for stable detonation in the explosive, thermal decomposition changes into detonation. To test these mechanisms measurements of delay to detonation were made with loose masses of lead azide, both Service and dextrinated, ranging from 10 to 200 mg. using previously described apparatus. The azides were wetted with measured volumes of liquids with various boiling points, including: water, benzene, quinoline, diethylene glycol, glycerol, dibutyl phthalate, benzyl benzoate, nujol, tricresyl phosphate, and the effect on the detonation was observed. Mixtures of benzene with nujol and with dibutyl phthalate were also investigated. Comparative measurements were made on the deflagration of cyclonite in the same apparatus, both dry and with added liquids. The effect of liquids on the detonation of lead azide when heated was found to belong broadly to one of two classes: (i) For liquids with the boiling points considerably below the temperature at which the test was being carried out, detonation followed after a longer delay than in the absence of liquid. There was evidence that the liquid first evaporated, and then normal detonation of the azide grains took place in the vapour phase thus formed. This behaviour was shown by the following liquids: liquid b.p. (°C) azide range of testing temperatures (°C) benzene 80 dextrinated 270-340 Service 325-350 water 100 dextrinated 270-340 Service 310-370 quinoline 238 dextrinated 300-350 diethylene glycol 244 dextrinated Service 260-350 320-360 A noteworthy feature was that the threshold detonation temperature was lower when the grains of azide were surrounded by various vapours in place of air (see also tables 22 and 24). azide vapour lowering of threshold temperature compared with air 10 mg. dextrin benzene 23° water 30° diethylene glycol 22° dibutyl phthalate (raised 5°) 10 mg. Service benzene no effect water (raised 3°) diethylene glycol 5° dibutyl phthalate 6° (ii) For liquids with boiling points considerably above the temperature of test, no detonation was observed. However, under certain circumstances a new phenomenon was observed, in that the lead azide ‘deflagrated’ in a manner closely resembling the behaviour of the (self-heating) deflagration of an explosive such as cyclonite. This is quite different from the sharp detonation obtained with loose azide in air, when the masses are small. When the boiling point was in the neighbourhood of the testing temperature, or with mixtures of liquids with boiling points above and below the testing temperature, both classes of behaviour were observed, according to the conditions of test. Further, the temperature coefficient of the induction period for azide wetted with these intermediate liquids suggested that detonation occurred after the liquid had been displaced by nitrogen produced by thermal decomposition of some of the lead azide. From the experimental results, it is concluded that ( a ) With the masses used, lead azide will detonate only when the grains are surrounded by gas or vapour. ( b ) Lead azide can deflagrate by a self-heating mechanism even under conditions where it will not detonate, e.g. when wetted by a liquid of very high boiling point such as tricresyl phosphate. These conclusions support the view that the 'normal’ mechanism of detonation of lead azide is controlled not by self-heating but by some process such as mass flow. When this normal mechanism fails to operate explosion may still occur by self-heating.

Applications of Photoelectron Microscopy

1976 ◽  
Vol 34 ◽  
pp. 506-507
Author(s):  
William J. Baxter
Keyword(s):  
Electron Microscopy ◽  
Thermal Decomposition ◽  
Chemical Composition ◽  
Ultraviolet Radiation ◽  
Thin Layer ◽  
Edge Effects ◽  
Electron Optics ◽  
Surface Layers ◽  
Crystalline Orientation ◽  
Fluorescent Screen

In this form of electron microscopy, photoelectrons emitted from a metal by ultraviolet radiation are accelerated and imaged onto a fluorescent screen by conventional electron optics. image contrast is determined by spatial variations in the intensity of the photoemission. The dominant source of contrast is due to changes in the photoelectric work function, between surfaces of different crystalline orientation, or different chemical composition. Topographical variations produce a relatively weak contrast due to shadowing and edge effects.Since the photoelectrons originate from the surface layers (e.g. ∼5-10 nm for metals), photoelectron microscopy is surface sensitive. Thus to see the microstructure of a metal the thin layer (∼3 nm) of surface oxide must be removed, either by ion bombardment or by thermal decomposition in the vacuum of the microscope.

Preparation and characterisation of vanadium pentoxide supported rhodium catalyst

1988 ◽  
Vol 46 ◽  
pp. 946-947
Author(s):  
A. Legrouri
Keyword(s):  
Aqueous Solution ◽  
Thermal Decomposition ◽  
Physicochemical Properties ◽  
Surface Area ◽  
Vanadium Pentoxide ◽  
High Purity ◽  
Gas Adsorption ◽  
Rhodium Catalyst ◽  
Optical Methods ◽  
Reducible Oxides

The industrial importance of metal catalysts supported on reducible oxides has stimulated considerable interest during the last few years. This presentation reports on the study of the physicochemical properties of metallic rhodium supported on vanadium pentoxide (Rh/V2O5). Electron optical methods, in conjunction with other techniques, were used to characterise the catalyst before its use in the hydrogenolysis of butane; a reaction for which Rh metal is known to be among the most active catalysts.V2O5 powder was prepared by thermal decomposition of high purity ammonium metavanadate in air at 400 °C for 2 hours. Previous studies of the microstructure of this compound, by HREM, SEM and gas adsorption, showed it to be non— porous with a very low surface area of 6m2/g3. The metal loading of the catalyst used was lwt%Rh on V2Q5. It was prepared by wet impregnating the support with an aqueous solution of RhCI3.3H2O.

Observations of the Thermal Decomposition of Brucite

1968 ◽  
Vol 26 ◽  
pp. 446-447
Author(s):  
P. L. Burnett ◽  
W. R. Mitchell ◽  
C. L. Houck
Keyword(s):  
Thermal Decomposition ◽  
Magnesium Oxide ◽  
Basal Plane ◽  
Magnesium Ions ◽  
A Value ◽  
Reaction Proceeds

Natural Brucite (Mg(OH)2) decomposes on heating to form magnesium oxide (MgO) having its cubic ﹛110﹜ and ﹛111﹜ planes respectively parallel to the prism and basal planes of the hexagonal brucite lattice. Although the crystal-lographic relation between the parent brucite crystal and the resulting mag-nesium oxide crystallites is well known, the exact mechanism by which the reaction proceeds is still a matter of controversy. Goodman described the decomposition as an initial shrinkage in the brucite basal plane allowing magnesium ions to shift their original sites to the required magnesium oxide positions followed by a collapse of the planes along the original <0001> direction of the brucite crystal. He noted that the (110) diffraction spots of brucite immediately shifted to the positions required for the (220) reflections of magnesium oxide. Gordon observed separate diffraction spots for the (110) brucite and (220) magnesium oxide planes. The positions of the (110) and (100) brucite never changed but only diminished in intensity while the (220) planes of magnesium shifted from a value larger than the listed ASTM d spacing to the predicted value as the decomposition progressed.

A magnetic super lattice

1987 ◽  
Vol 45 ◽  
pp. 360-361 ◽  
Author(s):  
M.D. Bentzon ◽  
J. v. Wonterghem ◽  
A. Thölén
Keyword(s):  
Thermal Decomposition ◽  
Oleic Acid ◽  
Magnetic Fluid ◽  
Magnetic Particles ◽  
Carbon Film ◽  
Thick Layer ◽  
Amorphous Iron ◽  
Super Lattice ◽  
Carrier Liquid ◽  
Median Diameter

We report on the oxidation of a magnetic fluid. The oxidation results in magnetic super lattice crystals. The “atoms” are hematite (α-Fe2O3) particles with a diameter ø = 6.9 nm and they are covered with a 1-2 nm thick layer of surfactant molecules.Magnetic fluids are homogeneous suspensions of small magnetic particles in a carrier liquid. To prevent agglomeration, the particles are coated with surfactant molecules. The magnetic fluid studied in this work was produced by thermal decomposition of Fe(CO)5 in Declin (carrier liquid) in the presence of oleic acid (surfactant). The magnetic particles consist of an amorphous iron-carbon alloy. For TEM investigation a droplet of the fluid was added to benzine and a carbon film on a copper net was immersed. When exposed to air the sample starts burning. The oxidation and electron irradiation transform the magnetic particles into hematite (α-Fe2O3) particles with a median diameter ø = 6.9 nm.

Supersonic jet spectrometry of chemical species resulting from thermal decomposition of polystyrene and polycarbonate

1992 ◽  
Vol 64 (19) ◽  
pp. 931A-940A ◽  
Author(s):  
Totaro Imasaka ◽  
Masami Hozumi ◽  
Nobuhiko Ishibashi
Keyword(s):  
Thermal Decomposition ◽  
Supersonic Jet ◽  
Chemical Species

Influence of thermal decomposition behavior of titanium precursors on (Ba,Sr)TiO3 thin films

2001 ◽  
Vol 11 (PR3) ◽  
pp. Pr3-675-Pr3-682 ◽  
Author(s):  
Y. S. Min ◽  
Y. J. Cho ◽  
D. Kim ◽  
J. H. Lee ◽  
B. M. Kim ◽  
...  
Keyword(s):  
Thin Films ◽  
Thermal Decomposition ◽  
Thermal Decomposition Behavior ◽  
Decomposition Behavior

THERMAL DECOMPOSITION OF IODINE DOPED POLYACETYLENE

1983 ◽  
Vol 44 (C3) ◽  
pp. C3-203-C3-205
Author(s):  
S. Pekker ◽  
G. Mihály
Keyword(s):  
Thermal Decomposition
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