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Formation of Boric Acid by Surface Oxidation of Amorphous Boron Powder: Characterization and Quantitative Estimation

Nandi A. K., Ghosh M., Newale S. P., Jadhav A. J., Prasanth H., Pandey R. K.

Central European Journal of Energetic Materials

2012

Vol. 9, nr 4

387-398

Amorphous Boron Powder (ABP) is used as a fuel in air breathing propulsion systems due to its high gravimetric and volumetric heat value. ABP is sensitive to air and undergoes slow oxidation during storage and handling, leading to the formation of a boric acid layer on the particle surface. This paper describes an analytical method for the estimation of boric acid in ABP. In-house samples obtained from the pilot plant of this laboratory, as well as commercial samples, were assayed for their boric acid content. The study is substantiated by characterization of the ABP samples by SEM with EDX and FTIR. The ageing characteristics of in-house boron powder was also studied.

Wpływ cząsteczek wody w B2O3 na właściwości niedomieszkowanych monokryształów InAs otrzymywanych metodą Czochralskiego

Orłowski W., Hruban A., Mirowska A., Strzelecka S.

Materiały Elektroniczne

2009

T. 37, nr 2

15-21

Opracowano warunki otrzymywania metodą Czochralskiego z hermetyzacją cieczową (Liquid Encapsulated Czochralski - LEC) bardzo czystych niedomieszkowanych monokryształów InAs typu n o ruchliwości elektronów μ > 22000 cm ² / Vs i koncentracji elektronów n < 3 x10^16 cm -³ w 300 K. Zbadano wpływ zawartości cząsteczek wody w topniku (B2O3) stosowanym do hermetyzacji stopionego wsadu na parametry elektryczne kryształów oraz na zawartość w nich domieszek resztkowych. Zbadano również wpływ czasu wygrzewania stopionego wsadu przed procesem krystalizacji na własności otrzymanych kryształów.

The aim of this work was to find out technological conditions that allow obtaining high purity undoped InAs single crystals with carrier concentration below 3xl0^16 cm -³ and carrier mobility over 22000 cm ² / Vs. Synthesis by injection method and Liquid Encapsulated Czochralski (LEC) crystal growth were applied. The influence of water content in B2O3 encapsulant (applied during injection synthesis and LEC growth) on electrical properties of InAs crystals and especially on dopants concentration was investigated. The influence of charge annealing duration before crystallization process on InAs crystals properties was also investigated.

Synthesis and Characterization of Solid Acid in System SnO2/B2O3

Viter V. N., Nagorny P. G.

Polish Journal of Chemistry

2008

Vol. 82, nr 11

2081-2087

SnO2/B2O3 materials with Sn/B molar ratio 1:1; 1:2 and 1:3 were synthesized from SnCl4, H3BO3 and (NH2)2CO. The samples contain SnO2 with different cristallinity and anamorphous borate phase. Their thermal transformations were investigated by DTA method. The surface acidity was investigated by TPR method using conversion of 2-methyl-3-butyn-2-ol (MBOH). The temperature maximum of MBOH dehydration for SnO2/B2O3 materials is close to that for ZrO2/SiO2 catalyst. On the surface of SnO2/B2O3 mainly strong acid sites were detected. In the case of B2O3/SiO2 (aerosil), samples have mainly weak acid sites. The surface of pure SnO2 has amphoteric sites. IR spectroscopy and MAS NMR spectra of 11B showed that SnO2/B2O3 materials had three- and four-coordinated B atoms.