Methods of Preparation of Amorphous Boron

Zhigach, A. F.; Stasinevich, D. C.

doi:10.1007/978-3-642-66620-9_13

Cited by 6 publications

(4 citation statements)

References 27 publications

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“…It is thought that dissociation occurs through the formation of atomic hydrogen molized on the hydride surface [10]. The mass spectrum H + of the anodic products shows that, upon heating in the temperature range 200−500°C, atomic hydrogen with a maximum of 320°C is mainly desorbed.…”

Section: Mghmentioning

confidence: 99%

A practical application of thermal desorption mass spectrometry for studying inhibitors and corrosion products

2008

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In the present review, examples of the practicality of applying thermal desorption mass spectrometry (TDMS) to study inhibitors and corrosion products are given. It is shown that the highly informative aspect of the method allows regularities of the processes occurring in volume, on surfaces, and in near-surface layers of steels and alloys to be established. The TDMS method makes it possible to identify adsorbed and chemisorbed inhibitors and corrosion products, as well as products of their destruction.

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Section: Mghmentioning

confidence: 99%

A practical application of thermal desorption mass spectrometry for studying inhibitors and corrosion products

2008

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“…The reduction is very quick and highly exothermic; finely divided material may react explosively [7].…”

Section: Productionmentioning

confidence: 99%

“…The optimum ratio B 2 O 3 : Mg is about 1.8 : 3 [7]. Reaction is carried out in vertical steel retorts shielded from oxygen by a flow of argon.…”

Section: Productionmentioning

confidence: 99%

Boron and Boron Alloys

Baudis

Fichte²

2000

Ullmann's Encyclopedia of Industrial Chemistry

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The article contains sections titled: 1. Boron 1.1. Structure and Polymorphism 1.2. Physical Properties 1.3. Chemical Properties 1.4. Production 1.5. Chemical Analysis, Storage, Safety 1.6. Uses, Economic Aspects 2. Ferroboron and Other Boron Master Alloys 2.1. Physical Properties 2.2. Chemical Properties 2.3. Raw Materials 2.4. Production 2.4.1. Carbothermic Production 2.4.2. Aluminothermic Production 2.5. Quality Specifications for Commercial Grades 2.6. Storage and Shipment 2.7. Chemical Analysis 2.8. Pollution Control 2.9. Uses 2.10. Economic Aspects 2.11. Toxicology and Industrial Hygiene

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“…Presently, the most popular method for the syn thesis of this hydride is the thermal cleavage of etherate {AlH 3 •xEt 2 O}, which was obtained by the Schlesinger reaction 1 (Eq. (1)) in the presence of small amounts of lithium tetrahydridoaluminate and tetrahydridoborate (10)(11)(12)(13)(14)(15) wt.% of aluminum hydride) followed by crystal lization of nonsolvated aluminum hydride (hereinafter, NAH) from solutions in an ether-ArH mixed solvent. 2 3 LiAlH 4 solv + AlCl 3 (1) It has been shown 3 that the concentration of alumi num hydride in a 1 : 1 (v/v) Et 2 O-ArH solution should not exceed 4 g L -1 for the process to occur successfully.…”

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confidence: 99%

“One-step” synthesis of nonsolvated aluminum hydride

2009

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The direct reaction of lithium tetrahydroaluminate with aluminum chloride in an ethertoluene mixture at temperatures ≥90 °С was studied. Under these conditions, nonsolvated aluminum hydride is formed in a yield ≥80%. The product formed represents agglomerates with the highly developed surface and has satisfactory hydrolytic and thermal stability but an increased lithium chloride content (0.25-2.2 wt.%). The decrease in the percentage of this impurity to 0.2 wt.% is achieved by using chloroalanes AlH 3-n Cl n •xOEt 2 (n ≤ 1) instead of aluminum chloride along with vigorous stirring and an increase in the synthesis-crystalliza tion temperature to ≥100 °С. The use of compounds based on magnesium tetrahydroaluminate, LiAlH 4 •Mg(AlH 4 ) 2 or LiCl•Mg(AlH 4 ) 2 , as modifying agents increases the thermal stability of the hydride and decreases the agglomeration of the crystals.The problems associated with the search for efficient hydrogen sources and materials for its storage are among the most important in the context of hydrogen power engineering. Diverse types and classes of substances that can be used as sources and/or accumulators of this gas have been considered and studied over the recent years. First of all, these are simple and complex hydrides of light metals containing the largest amount of hydrogen per mass unit. Among them, aluminum hydride can be recog nized as one of the most efficient in chemical and physi cochemical properties, because its thermolysis requires low energy expenses but produces 10 wt.% hydrogen, while twice as large amount of hydrogen is evolved upon hydrolysis.Unfortunately, aluminum hydride in the nonsolvated state is one of the most inaccessible and expensive binary hydrides. Presently, the most popular method for the syn thesis of this hydride is the thermal cleavage of etherate {AlH 3 •xEt 2 O}, which was obtained by the Schlesinger reaction 1 (Eq. (1)) in the presence of small amounts of lithium tetrahydridoaluminate and tetrahydridoborate (10-15 wt.% of aluminum hydride) followed by crystal lization of nonsolvated aluminum hydride (hereinafter, NAH) from solutions in an ether-ArH mixed solvent. 2 3 LiAlH 4 solv + AlCl 3 •xEt 2 O solv 4 AlH 3 •xEt 2 O solv + 3 LiCl solid (1) It has been shown 3 that the concentration of alumi num hydride in a 1 : 1 (v/v) Et 2 O-ArH solution should not exceed 4 g L -1 for the process to occur successfully. The concentration can be increased to 5-6 g L -1 with addition of a large amount of LiAlH 4 and LiBH 4 (up to 25-45 wt.% each of aluminum hydride). 3 All further attempts to increase the concentration resulted in the spontaneous precipitation of the "dead" solvate {AlH 3 •0.33 Et 2 O} n (see Ref. 4) and a simultaneous decrease in the yield of the nonsolvated material and deterioration of its quality.Some increase in the hydride concentration (more exactly, effective concentration (С eff AlH 3 ) determined from its amount calculated from the reaction stoichio metry and related to the total weight of solvents used in crystallization) was achieved 5 b...

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Methods of Preparation of Amorphous Boron

Cited by 6 publications

References 27 publications

A practical application of thermal desorption mass spectrometry for studying inhibitors and corrosion products

A practical application of thermal desorption mass spectrometry for studying inhibitors and corrosion products

Boron and Boron Alloys

“One-step” synthesis of nonsolvated aluminum hydride

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