Low-Temperature High-Efficiency Preparation of TiB2 Micro-Platelets via Boro/Carbothermal Reduction in Microwave Heated Molten Salt

Abstract

A molten-salt and microwave co-facilitated boro/carbothermal reduction methodology was developed for low temperature high-efficiency synthesis of TiB2 powders. By using relatively inexpensive titanium oxide (TiO2), boron carbide (B4C) and amorphous carbon (C) as raw materials, single-phase TiB2 powders were prepared after 60 min at as low as 1150 °C or after only 20 min at 1200 °C. Such synthesis conditions were remarkably milder than those required by the conventional reduction routes using the identical reducing agent. As-synthesized TiB2 powders exhibited single-crystalline nature and well-grown hexagonal-platelet-like morphology. The achievement of low temperature high-efficiency preparation of high-quality TiB2 microplatelets in the present work was mainly attributable to the synergistic effects of molten-salt medium and microwave heating.

Low temperature controllable synthesis of transition metal and rare earth borides mediated by molten salt

“…[215][216][217][218] It also has been introduced by the corresponding author's group to an MSS process to replace the conventional furnace heating, leading to the development of an improved MSS technique, referred to as 'microwave-assisted molten salt synthesis (MA-MSS)'. [219][220][221][222][223][224][225] Table 7 summarises the studies on MA-MSS of metal boride-based powders. [219][220][221][222][223][224][225] As shown, by using microwave heating combined with MSM-BCRS, phase pure ZrB 2 nanorods, TiB 2 microplatelets and TaB 2 nanoflowers were successfully prepared in the NaCl-KCl eutectic salt after only 20 min at 1100-1200 °C.…”

Boron carbide amorphous solid with tunable band gap

“…Among these methods is the microwave-assisted carbothermal reduction, which is fast and cost-effective in synthesizing B x C nanomaterials, such as B 4 C boron carbide nanocrystalline powders [19,25] and carbon-rich BC 2 amorphous powders [26]. The carbothermal reduction technique has also been employed to synthesize metal nitrides [27], TiC powders [28], ZrB 2 powders [29], and TiB 2 powders [30]. Here, semiconducting boron carbon amorphous compounds with tunable bandgap were first synthesized using the microwaveassisted carbothermal reaction.…”

High Temperature Ceramic Materials

“…This Special Issue, “High Temperature Ceramic Materials”, released by Materials, is dedicated to original research articles from the ceramics/refractories communities, presenting some of the latest work in a few topical areas listed above. In total, 15 good quality articles have been included [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 ], the interesting points from each of which are briefly highlighted as follows.…”

“…Interestingly, the MSS technique also can be extended or modified to synthesise other types of high melting point ceramic materials with novel morphologies for both structural and functional applications. As demonstrated by Liu et al [ 7 ], by combining it with microwave heating, TiB 2 microplatelets can be synthesised at a lowered temperature and/or in a shorter time. On the other hand, by combining it with chemical vapour deposition, 1-D necklace-like SiC/SiO 2 heterojunctions can be prepared without using any catalyst [ 14 ].…”

“…In the past two decades, and in particular, in recent years, significant amounts of research work have been carried out aiming to improve their properties/performance; enhance their service lives; and to deal with several critical issues related to production cost, sustainability, and eco-friendliness. Some of these topical areas include: (1) exploration of new system of ceramics, (2) low temperature synthesis of high quality ceramic particles, (3) graphene and/or carbon nanotube reinforced ceramic composites, (4) "green" low-carbon refractory composites, (5) energy-saving lightweight ceramics, (6) novel catalytic synthesis of ceramic materials, (7) high/low thermal conductivity ceramics, (8) self-healing ceramic composites, (9) ultra-high temperature ceramics, (10) additive manufacturing of ceramics, (11) directionally solidified eutectic ceramics, (12) functional ceramic coatings, (13) plasma/cold/flash sintering, (14) recycling of waste materials, (15) new testing techniques, and (16) ceramic materials modelling/simulation. This Special Issue, "High Temperature Ceramic Materials", released by Materials, is dedicated to original research articles from the ceramics/refractories communities, presenting some of the latest work in a few topical areas listed above.…”