Synthesis of titanium boride (TiB)₂ nanocrystallites by solution-phase processing

Abstract

Nanocrystalline TiB 2 is prepared by reaction of NaBH 4 and TiCU. The initial solution-phase reaction affords an amorphous precursor powder from which 5-100 nm TiB 2 crystallites are obtained upon annealing at 900-1100 °C. Crystallite sizes depend on the annealing temperature and other processing parameters. Crystallite morphology is size dependent; crystallites smaller than 12-15 nm are cuboidal, whereas crystallites larger than 12-15 nm are hexagonal platelets. The procedure affords gram quantities of the smallest available TiB2 nanocrystallites.

Synthesis of nano-titanium diboride powders by carbothermal reduction

“…A number of processes exist for synthesizing TiB 2 powder such as direction reaction of Ti and B, 7 metal-thermal reduction, 8 arc-plasma method 9,10 and gasphase combustion (flame) method. 11 Normally, TiB 2 powder is commercially produced by reduction of titanium oxide with either boron oxide and carbon or an alkali metal and boron oxide. [15][16][17] Among above mentioned processing techniques, the carbothermal reduction process is commercially used by far the cheapest because of inexpensive raw materials and simple process.…”

Effect of NaCl on the synthesis of TiB2 powder by a self-propagating high-temperature synthesis technique

“…These excellent properties make it a potential material for applications as ballistic armour, coating on cutting tools, cathodes for electro-chemical processing of aluminium (Hall -Heroult process), high-temperature evaporation boats, high-temperature sleeves and as dispersoid in metal or ceramic matrix composites [1,2]. Several methods for the preparation of TiB 2 powders are reported, amongst them, the borothermic reduction of titania, carbothermic reduction of the TiO 2 and B 2 O 3 powder mixture, reduction of titania with boron carbide [2,3], reactions of elemental powders by powder metallurgical route, solution-phase processing route by reaction of NaBH 4 and TiCl 4 [4], gas-phase combustion synthesis process based on the gas-phase Na/TiCl 4 /BCl 3 flame reaction [5] and self-propagating high-temperature synthesis (SHS) technique are noteworthy. In the SHS process, once the combustion reaction is ignited, extremely high temperatures can be achieved within a very short time.…”

A convenient solid-state reaction route to nanocrystalline TiB2

“…Recently, various efforts have been made to synthesize TiB 2 at lower temperatures, control morphology or simplify reaction procedures. For example, Gu et al [6] prepared nanocrystalline titanium diboride via a benzene-thermal reaction of metallic sodium with amorphous boron powder and titanium tetrachloride at 400°C; Axelbaum et al [7] reported to synthesize nanometer-sized TiB 2 particles by gas-phase combustion reaction of sodium vapor with TiCl 4 and BCl 3 in a high-temperature flow reactor; Bates et al [8] reported a solution-phase reaction of NaBH 4 and TiCl 4 to produce an amorphous precursor powder, which was then annealed at 900-1100°C to obtain nanocrystalline TiB 2 .…”