Abstract
The α-rhombohedral and β-rhombohedral crystal structures of pure elemental boron powders have been synthesized via gas phase thermal dissociation of BCl3 by H2 on a quartz substrate. The parameters affecting the crystal structures of the final products and the process efficiency, such as BCl3/H2 molar ratio (1/2 and 1/4) and reaction temperature (1173 K to 1373 K [900 °C to 1100 °C]), have been examined. The experimental apparatus of original design has enabled boron powders to be obtained at temperatures lower than those in the literature. The surface/powder separation problem encountered previously with different substrate materials has been avoided. Boron powders have been synthesized with a minimum purity of 99.99 pct after repeated HF leaching. The qualitative analysis of exhaust gases has been conducted using a Fourier transform infrared spectroscope (FTIR). The synthesized powders have been characterized using an X-ray powder diffractometer (XRD) and scanning electron microscope (SEM) techniques. The results of the reactions have been compared with equilibrium predictions performed using the FactSage 6.2 (Center for Research in Computational Thermochemistry, Montreal, Canada) thermochemical software.
Original language | English |
---|---|
Pages (from-to) | 568-574 |
Number of pages | 7 |
Journal | Metallurgical and Materials Transactions B: Process Metallurgy and Materials Processing Science |
Volume | 42 |
Issue number | 3 |
DOIs | |
Publication status | Published - Jun 2011 |
Funding
This work was supported by the National Boron Research Institute of Turkey (BOREN) with the Project No: 2009-C¸ 0241. The authors would like to express their appreciation to Assistant Professor Dr. Bora Derin for his help in using the FactSage 6.2 thermochemical software.
Funders | Funder number |
---|---|
National Boron Research Institute of Turkey | |
Ulusal Bor Araştırma Enstitüsü | 2009-C¸ 0241 |