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Title: Effect of HCl concentration on TiB{sub 2} separation from a self-propagating high-temperature synthesis (SHS) product

Abstract

This paper presents a synthesis of TiB{sub 2} powder via self-propagating high-temperature synthesis (SHS) method using a mixture of TiO{sub 2}, B{sub 2}O{sub 3} and Mg followed by acid leaching. In the acid leaching step, the MgO content in the SHS product was leached in different HCl concentrations. X-ray diffraction (XRD) analysis showed that when 9.3 M HCl was used, the leached SHS product was found similar to that of the commercial TiB{sub 2} powder. However, scanning electron microscopy (SEM) and BET surface area analysis revealed that the leached product was agglomerated and exhibited very high surface area.

Authors:
 [1];  [2];  [1]
  1. Metallurgical and Materials Engineering, Istanbul Technical University, Maslak, Istanbul 34469 (Turkey)
  2. Metallurgical and Materials Engineering, Istanbul Technical University, Maslak, Istanbul 34469 (Turkey). E-mail: bderin@itu.edu.tr
Publication Date:
OSTI Identifier:
21000592
Resource Type:
Journal Article
Resource Relation:
Journal Name: Materials Research Bulletin; Journal Volume: 42; Journal Issue: 2; Other Information: DOI: 10.1016/j.materresbull.2006.05.032; PII: S0025-5408(06)00246-7; Copyright (c) 2006 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; BORATES; BORON OXIDES; CERAMICS; CHEMICAL PREPARATION; HYDROCHLORIC ACID; LEACHING; MAGNESIUM OXIDES; SCANNING ELECTRON MICROSCOPY; SURFACE AREA; TITANIUM BORIDES; TITANIUM OXIDES; X-RAY DIFFRACTION

Citation Formats

Demircan, Umut, Derin, Bora, and Yuecel, Onuralp. Effect of HCl concentration on TiB{sub 2} separation from a self-propagating high-temperature synthesis (SHS) product. United States: N. p., 2007. Web. doi:10.1016/j.materresbull.2006.05.032.
Demircan, Umut, Derin, Bora, & Yuecel, Onuralp. Effect of HCl concentration on TiB{sub 2} separation from a self-propagating high-temperature synthesis (SHS) product. United States. doi:10.1016/j.materresbull.2006.05.032.
Demircan, Umut, Derin, Bora, and Yuecel, Onuralp. Thu . "Effect of HCl concentration on TiB{sub 2} separation from a self-propagating high-temperature synthesis (SHS) product". United States. doi:10.1016/j.materresbull.2006.05.032.
@article{osti_21000592,
title = {Effect of HCl concentration on TiB{sub 2} separation from a self-propagating high-temperature synthesis (SHS) product},
author = {Demircan, Umut and Derin, Bora and Yuecel, Onuralp},
abstractNote = {This paper presents a synthesis of TiB{sub 2} powder via self-propagating high-temperature synthesis (SHS) method using a mixture of TiO{sub 2}, B{sub 2}O{sub 3} and Mg followed by acid leaching. In the acid leaching step, the MgO content in the SHS product was leached in different HCl concentrations. X-ray diffraction (XRD) analysis showed that when 9.3 M HCl was used, the leached SHS product was found similar to that of the commercial TiB{sub 2} powder. However, scanning electron microscopy (SEM) and BET surface area analysis revealed that the leached product was agglomerated and exhibited very high surface area.},
doi = {10.1016/j.materresbull.2006.05.032},
journal = {Materials Research Bulletin},
number = 2,
volume = 42,
place = {United States},
year = {Thu Feb 15 00:00:00 EST 2007},
month = {Thu Feb 15 00:00:00 EST 2007}
}
  • Extensive comparisons have been conducted between experimental and theoretical results for the SHS combustion characteristics of a number of solid-solid systems. The heterogeneous flame propagation theory describes a premixed mode of bulk flame propagation supported by the nonpremixed reaction of dispersed nonmetal (or higher melting point metal) particles in the liquid metal, with finite-rate reaction at the particle surface and temperature-sensitive Arrhenius-type condensed-phase mass diffusivity. Systems examined are those of borides (TiB[sub 2], ZrB[sub 2], and HfB[sub 2]) and intermetallic compounds (NiAl, TiCo, and TiNi). By using a consistent set of physico-chemical parameters for these systems, satisfactorily quantitative agreement ismore » demonstrated for the effects of mixture ratio, degree of dilution, and particle size on the burning velocity. Experimental flammability limits are also predicted by the theory.« less
  • Since the discovery of the grain refinement effect of aluminum by titanium, especially with the existence of B or C in 1950, grain refiners are widely accepted in industry for microstructure control of aluminum alloys. Research on this topic is to obtain the highest grain refinement efficiency with the lowest possible addition of master alloy. It is widely accepted that the morphology and size of TiAl{sub 3} particles, which are known as heterogeneous nucleation centers, are important factors deterring the grain refinement efficiency. Fine TiAl{sub 3} particles are favorable. The grain refinement process shows a heredity phenomenon, which means thatmore » structural information from initial materials transfers through a melt to the final product. It is important to find the connection between microstructural parameters of the master alloy and the final product. To improve the quality of Al-Ti-B master alloys for the use as a grain refiner, a new method based on SHS (self-propagating high-temperature synthesis) technology has been developed in Samara State Technical University to produce the master alloys. SHS, as a new method for preparation of materials, was first utilized by Merzhanov in 1967. This method uses the energy from highly exothermic reactions to sustain the chemical reaction in a combustion wave. The advantages of SHS include simplicity, low energy requirement, and higher product purity. Because SHS reactions can take place between elemental reactants, it is easy to control product composition. The purposes of this investigation were to fabricate an SHS Al-5%Ti-1%B master alloy, to analyze its structure and to test its grain refining performance.« less
  • Molybdenum and tungsten disulfide nanoplates were produced by self-propagating high-temperature synthesis in argon atmosphere. This method provides an easy way to produce MoS{sub 2} and WS{sub 2} from nanoplates up to single- and several layers. The Raman peak intensities corresponding to in-plane E{sup 1}{sub 2g} and out-of-plane A{sub 1g} vibration modes and their shifts strongly depend on the thicknesses of the MoS{sub 2} and WS{sub 2} platelets indicating size-dependent scaling laws and properties. An electron beam irradiation of MoS{sub 2} and WS{sub 2} powders leads to an occurrence of pulsed cathodoluminescence (PCL) spectra at 575 nm (2.15 eV) and 550 nm (2.25 eV) characteristicmore » to their intrinsic band gaps. For the combination of MoS{sub 2} and WS{sub 2} nanopowders, a PCL shoulder at 430 nm (2.88 eV) was observed, which is explained by the radiative electron-hole recombination at the MoS{sub 2}/WS{sub 2} grain boundaries. The luminescence decay kinetics of the MoS{sub 2}/WS{sub 2} nanoplates appears to be slower than for individual MoS{sub 2} and WS{sub 2} platelets due to a spatial separation of electrons and holes at MoS{sub 2}/WS{sub 2} junction resulting in extension of recombination time.« less
  • High-purity tungsten was prepared by self-propagating high-temperature synthesis (SHS) process from a mixture of CaO{center_dot}WO{sub 3} and Mg. The complete reduction of CaO{center_dot}WO{sub 3} required a 33{percent} excess of magnesium over the stoichiometric molar ratio Mg/CaO{center_dot}WO{sub 3} of 3:1. The MgO and CaO in the product was leached with an HCl solution. The product tungsten had a purity of 99.980{percent} which was higher than that of the reactants. The high purity results because the non tungsten reactants and products are volatilized by the high temperatures generated during the rapid exothermic SHS reaction and are dissolved during HCl leaching of themore » product. {copyright} {ital 1996 Materials Research Society.}« less
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